WorldWideScience

Sample records for aura tropospheric emission

  1. Satellite observations of peroxyacetyl nitrate from the Aura Tropospheric Emission Spectrometer

    Science.gov (United States)

    Payne, V. H.; Alvarado, M. J.; Cady-Pereira, K. E.; Worden, J. R.; Kulawik, S. S.; Fischer, E. V.

    2014-11-01

    We present a description of the algorithm used to retrieve peroxyacetyl nitrate (PAN) concentrations from the Aura Tropospheric Emission Spectrometer (TES). We describe the spectral microwindows, error analysis, and the utilization of a priori and initial guess information provided by the GEOS-Chem global chemical transport model. The TES PAN retrievals contain up to one degree of freedom for signal. In general, the retrievals are most sensitive to PAN in the mid-troposphere. Estimated single-measurement uncertainties are on the order of 30 to 50%. The detection limit for a single TES measurement is dependent on the atmospheric and surface conditions as well as on the instrument noise. For observations where the cloud optical depth is less than 0.5, we find that the TES detection limit for PAN is in the region of 200 to 300 pptv. We show that PAN retrievals capture plumes associated with boreal burning. Retrievals over the Northern Hemisphere Pacific in springtime show spatial features that are qualitatively consistent with the expected distribution of PAN in outflow of Asian pollution.

  2. Evidence of Convective Redistribution of Carbon Monoxide in Aura Tropospheric Emission Sounder (TES) and Microwave Limb Sounder (MLS) Observations

    Science.gov (United States)

    Manyin, Michael; Douglass, Anne; Schoeberl, Mark

    2010-01-01

    Vertical convective transport is a key element of the tropospheric circulation. Convection lofts air from the boundary layer into the free troposphere, allowing surface emissions to travel much further, and altering the rate of chemical processes such as ozone production. This study uses satellite observations to focus on the convective transport of CO from the boundary layer to the mid and upper troposphere. Our hypothesis is that strong convection associated with high rain rate regions leads to a correlation between mid level and upper level CO amounts. We first test this hypothesis using the Global Modeling Initiative (GMI) chemistry and transport model. We find the correlation is robust and increases as the precipitation rate (the strength of convection) increases. We next examine three years of CO profiles from the Tropospheric Emission Sounder (TES) and Microwave Limb Sounder (MLS) instruments aboard EOS Aura. Rain rates are taken from the Tropical Rainfall Measuring Mission (TRMM) 3B-42 multi-satellite product. Again we find a correlation between mid-level and upper tropospheric CO, which increases with rain rate. Our result shows the critical importance of tropical convection in coupling vertical levels of the troposphere in the transport of trace gases. The effect is seen most clearly in strong convective regions such as the Inter-tropical Convergence Zone.

  3. Satellite observations of ethylene (C2H4) from the Aura Tropospheric Emission Spectrometer: A scoping study

    Science.gov (United States)

    Dolan, Wayana; Payne, Vivienne H.; Kualwik, Susan S.; Bowman, Kevin W.

    2016-09-01

    We present a study focusing on detection and initial quantitative estimates of ethylene (C2H4) in observations from the Tropospheric Emission Spectrometer (TES), a Fourier transform spectrometer aboard the Aura satellite that measures thermal infrared radiances with high spectral resolution (0.1 cm-1). We analyze observations taken in support of the 2008 Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) mission and demonstrate the feasibility of future development of C2H4 into a TES standard product. In the Northern Hemisphere, C2H4 is commonly associated with boreal fire plumes, motor vehicle exhaust and petrochemical emissions. It has a short lifetime (∼14-32 h) in the troposphere due to its reaction with OH and O3. Chemical destruction of C2H4 in the atmosphere leads to the production of ozone and other species such as carbon monoxide (CO) and formaldehyde. Results indicate a correlation between C2H4 and CO in boreal fire plumes. Quantitative C2H4 estimates are sensitive to assumptions about the plume height and width. We find that C2H4 greater than 2-3 ppbv can be detected in a single TES observation (for a fire plume at 3 km altitude and 1.5 km width). Spatial averaging will be needed for surface-peaking profiles where TES sensitivity is lower.

  4. Tropospheric and Stratospheric Ozone From Assimilation of Aura Data

    Science.gov (United States)

    Stajner, I.; Wargan, K.; Chang, L.; Hayashi, H.; Pawson, S.; Froidevaux, L.; Livesey, N.; Bhartia, P. K.; Bowman, K.

    2006-05-01

    Ozone is an atmospheric trace gas with multiple impacts on the environment. Global ozone fields are needed for air quality predictions, estimation of the ultraviolet radiation reaching the surface, climate-radiation studies, and ozone may also have an impact on longer-term weather predictions. We estimate global ozone fields in the stratosphere and troposphere by combining the data from the EOS Aura satellite with an ozone model using data assimilation. Ozone exhibits a large temporal variability in the lower stratosphere. Our previous work showed that assimilation of satellite data from limb-sounding geometry helps constrain ozone profiles in that region. We assimilated ozone data from the Aura Microwave Limb Sounder (MLS) and the Ozone Monitoring Instrument (OMI) into the ozone system at NASA's Global Modeling and Assimilation Office (GMAO). Ozone is transported within a general circulation model (GCM) which includes parameterizations for stratospheric photochemistry, tropospheric chemistry, and a simple scheme for heterogeneous ozone loss. The focus of this study is on the representation of ozone in the lower stratosphere and tropospheric ozone columns. We plan to extend studies of tropospheric ozone distribution through assimilation of ozone data from the Tropospheric Emission Spectrometer (TES). Comparisons with ozone sondes and occultation data show that assimilation of Aura data provides a good representation of ozone gradients and variability in the lower stratosphere. We proceed by separating the contributions to temporal changes in the ozone field into those that are due to the model and those that are due to the assimilation of Aura data. We discuss the impacts of Aura data and their role in the representation of ozone variability in the lower stratosphere and troposphere.

  5. Connecting Surface Emissions, Convective Uplifting, and Long-Range Transport of Carbon Monoxide in the Upper Troposphere: New Observations from the Aura Microwave Limb Sounder

    Science.gov (United States)

    Jiang, Jonathan H.; Livesey, Nathaniel J.; Su, Hui; Neary, Lori; McConnell, John C.; Richards, Nigel A. D.

    2007-01-01

    Two years of observations of upper tropospheric (UT) carbon monoxide (CO) from the Aura Microwave Limb Sounder are analyzed; in combination with the CO surface emission climatology and data from the NCEP analyses. It is shown that spatial distribution, temporal variation and long-range transport of UT CO are closely related to the surface emissions, deep-convection and horizontal winds. Over the Asian monsoon region, surface emission of CO peaks in boreal spring due to high biomass burning in addition to anthropogenic emission. However, the UT CO peaks in summer when convection is strongest and surface emission of CO is dominated by anthropogenic source. The long-range transport of CO from Southeast Asia across the Pacific to North America, which occurs most frequently during boreal summer, is thus a clear imprint of Asian anthropogenic pollution influencing global air quality.

  6. A joint data record of tropospheric ozone from Aura-TES and MetOp-IASI

    Science.gov (United States)

    Oetjen, Hilke; Payne, Vivienne H.; Neu, Jessica L.; Kulawik, Susan S.; Edwards, David P.; Eldering, Annmarie; Worden, Helen M.; Worden, John R.

    2016-08-01

    The Tropospheric Emission Spectrometer (TES) on Aura and Infrared Atmospheric Sounding Interferometer (IASI) on MetOp-A together provide a time series of 10 years of free-tropospheric ozone with an overlap of 3 years. We characterise the differences between TES and IASI ozone measurements and find that IASI's coarser vertical sensitivity leads to a small (< 5 ppb) low bias relative to TES for the free troposphere. The TES-IASI differences are not dependent on season or any other factor and hence the measurements from the two instruments can be merged, after correcting for the offset, in order to study decadal-scale changes in tropospheric ozone. We calculate time series of regional monthly mean ozone in the free troposphere over eastern Asia, the western United States (US), and Europe, carefully accounting for differences in spatial sampling between the instruments. We show that free-tropospheric ozone over Europe and the western US has remained relatively constant over the past decade but that, contrary to expectations, ozone over Asia in recent years does not continue the rapid rate of increase observed from 2004 to 2010.

  7. Global tropospheric NO2 profiles obtained from a cloud-slicing technique applied to the Aura OMI observations

    Science.gov (United States)

    Choi, S.; Joiner, J.; Lamsal, L. N.; Marchenko, S. V.; Krotkov, N. A.

    2016-12-01

    Nitrogen dioxide (NO2) is an important trace species in the troposphere; it has adverse human health effects and also contributes to the formation of tropospheric ozone, a criteria pollutant and climate agent. We derive tropospheric NO2 volume mixing ratio (VMR) profiles by applying a cloud slicing technique to data from the Ozone Monitoring Instrument (OMI) on the Aura satellite. In the cloud-slicing approach, the slope of the above-cloud NO2 column versus the cloud scene pressure is proportional to the NO2 VMR. We apply this technique to OMI O2-O2 cloud scene pressures and above-cloud NO2 vertical column densities from a differential optical absorption spectroscopy (DOAS) algorithm. We derived a global seasonal climatology of tropospheric NO2 VMR profiles in cloudy conditions and compare the results with aircraft profiles measured during the NASA Intercontinental Chemical Transport Experiment Phase B (INTEX-B) campaign in 2006. An analysis of our cloud slicing NO2 profiles indicates signatures of uplifted and transported anthropogenic NOx in the middle troposphere as well as lightning-generated NOx in the upper troposphere. We expect that this technique can be applied to future geostationary missions including the NASA Earth Ventures Instrument (EVI) 1 selected mission Tropospheric Emissions: Monitoring of Pollution (TEMPO) over North America, the Korean Geostationary Environment Monitoring Spectrometer (GEMS) over the Asia-Pacific region, and the European Space Agency (ESA) Sentinel-4 over Europe.

  8. Science Accomplishments from a Decade of Aura OMI/MLS Tropospheric Ozone Measurements

    Science.gov (United States)

    Ziemke, Jerald R.; Douglass, Anne R.; Joiner, Joanna; Duncan, Bryan N.; Olsen, Mark A.; Oman, Luke D.; Witte, Jacquelyn C.; Liu, X.; Wargan, K.; Schoeberl, Mark R.; Strahan, Susan E.; Pawson, Steven; Bhartia, Pawan K.; Newman, Paul A.; Froidevaux, Lucien; Cooper, Owen R.; Haffner, David P.

    2014-01-01

    Measurements of tropospheric ozone from combined Aura OMI and MLS instruments have yielded a large number of new and important science discoveries over the last decade. These discoveries have generated a much greater understanding of biomass burning, lightning NO, and stratosphere-troposphere exchange sources of tropospheric ozone, ENSO dynamics and photochemistry, intra-seasonal variability-Madden-Julian Oscillation including convective transport, radiative forcing, measuring ozone pollution from space, improvements to ozone retrieval algorithms, and evaluation of chemical-transport and chemistry-climate models. The OMI-MLS measurements have been instrumental in giving us better understanding of the dynamics and chemistry involving tropospheric ozone and the many drivers affecting the troposphere in general. This discussion will provide an overview focusing on our main science results.

  9. The Aura Mission

    Science.gov (United States)

    Schoeberl, Mark R.

    2008-01-01

    Aura was designed to probe the chemistry of the troposphere as well as the stratosphere. Two instruments, the Microwave Limb Sounder, the Tropospheric Emission Spectrometer (TES) and the Ozone Monitoring Instrument (OMI) have provided some remarkable information on pollution, long range pollution transport and strat-trop exchange. This talk will review some of the more startling observations and some new science that we are seeing in the Aura data.

  10. The Aura Mission

    Science.gov (United States)

    Schoeberl, Mark R.

    2008-01-01

    Aura was designed to probe the chemistry of the troposphere as well as the stratosphere. Two instruments, the Microwave Limb Sounder, the Tropospheric Emission Spectrometer (TES) and the Ozone Monitoring Instrument (OMI) have provided some remarkable information on pollution, long range pollution transport and strat-trop exchange. This talk will review some of the more startling observations and some new science that we are seeing in the Aura data.

  11. Methane from the Tropospheric Emission Spectrometer (TES)

    Science.gov (United States)

    Payne, Vivienne; Worden, John; Kulawik, Susan; Frankenberg, Christian; Bowman, Kevin; Wecht, Kevin

    2012-01-01

    TES V5 CH4 captures latitudinal gradients, regional variability and interannual variation in the free troposphere. V5 joint retrievals offer improved sensitivity to lower troposphere. Time series extends from 2004 to present. V5 reprocessing in progress. Upper tropospheric bias. Mitigated by N2O correction. Appears largely spatially uniform, so can be corrected. How to relate free-tropospheric values to surface emissions.

  12. NO2 Total and Tropospheric Vertical Column Densities from OMI on EOS Aura: Update

    Science.gov (United States)

    Gleason, J.F.; Bucsela, E.J.; Celarier, E.A.; Veefkind, J.P.; Kim, S.W.; Frost, G.F.

    2009-01-01

    The Ozone Monitoring Instrument (OMI), which is on the EOS AURA satellite, retrieves vertical column densities (VCDs) of NO2, along with those of several other trace gases. The relatively high spatial resolution and daily global coverage of the instrument make it particularly well-suited to monitoring tropospheric pollution at scales on the order of 20 km. The OMI NO2 algorithm distinguishes polluted regions from background stratospheric NO2 using a separation algorithm that relies on the smoothly varying stratospheric NO2 and estimations of both stratospheric and tropospheric air mass factors (AMFs). Version 1 of OMI NO2 data has been released for public use. An overview of OMI NO2 data, some recent results and a description of the improvements for version 2 of the algorithm will be presented.

  13. NO2 Total and Tropospheric Vertical Column Densities from OMI on EOS Aura: Update

    Science.gov (United States)

    Gleason, J.F.; Bucsela, E.J.; Celarier, E.A.; Veefkind, J.P.; Kim, S.W.; Frost, G.F.

    2009-01-01

    The Ozone Monitoring Instrument (OMI), which is on the EOS AURA satellite, retrieves vertical column densities (VCDs) of NO2, along with those of several other trace gases. The relatively high spatial resolution and daily global coverage of the instrument make it particularly well-suited to monitoring tropospheric pollution at scales on the order of 20 km. The OMI NO2 algorithm distinguishes polluted regions from background stratospheric NO2 using a separation algorithm that relies on the smoothly varying stratospheric NO2 and estimations of both stratospheric and tropospheric air mass factors (AMFs). Version 1 of OMI NO2 data has been released for public use. An overview of OMI NO2 data, some recent results and a description of the improvements for version 2 of the algorithm will be presented.

  14. A Global Climatology of Tropospheric and Stratospheric Ozone Derived from Aura OMI and MLS Measurements

    Science.gov (United States)

    Ziemke, J.R.; Chandra, S.; Labow, G.; Bhartia, P. K.; Froidevaux, L.; Witte, J. C.

    2011-01-01

    A global climatology of tropospheric and stratospheric column ozone is derived by combining six years of Aura Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) ozone measurements for the period October 2004 through December 2010. The OMI/MLS tropospheric ozone climatology exhibits large temporal and spatial variability which includes ozone accumulation zones in the tropical south Atlantic year-round and in the subtropical Mediterranean! Asia region in summer months. High levels of tropospheric ozone in the northern hemisphere also persist in mid-latitudes over the eastern North American and Asian continents extending eastward over the Pacific Ocean. For stratospheric ozone climatology from MLS, largest ozone abundance lies in the northern hemisphere in the latitude range 70degN-80degN in February-April and in the southern hemisphere around 40degS-50degS during months August-October. The largest stratospheric ozone abundances in the northern hemisphere lie over North America and eastern Asia extending eastward across the Pacific Ocean and in the southern hemisphere south of Australia extending eastward across the dateline. With the advent of many newly developing 3D chemistry and transport models it is advantageous to have such a dataset for evaluating the performance of the models in relation to dynamical and photochemical processes controlling the ozone distributions in the troposphere and stratosphere.

  15. Global Free-tropospheric NO2 Abundances Derived Using a Cloud Slicing Technique from AURA OMI

    Science.gov (United States)

    Choi, S.; Joiner, J.; Choi, Y.; Duncan, B.N.; Vasilkov, A.; Krotkov, N.; Bucsela, E.J.

    2014-01-01

    We derive free-tropospheric NO2 volume mixing ratios (VMRs) by applying a cloud-slicing technique to data from the Ozone Monitoring Instrument (OMI) on the Aura satellite. In the cloud-slicing approach, the slope of the above-cloud NO2 column versus the cloud scene pressure is proportional to the NO2 VMR. In this work, we use a sample of nearby OMI pixel data from a single orbit for the linear fit. The OMI data include cloud scene pressures from the rotational-Raman algorithm and above-cloud NO2 vertical column density (VCD) (defined as the NO2 column from the cloud scene pressure to the top of the atmosphere) from a differential optical absorption spectroscopy (DOAS) algorithm. We compare OMI-derived NO2 VMRs with in situ aircraft profiles measured during the NASA Intercontinental Chemical Transport Experiment Phase B (INTEX-B) campaign in 2006. The agreement is generally within the estimated uncertainties when appropriate data screening is applied. We then derive a global seasonal climatology of free-tropospheric NO2 VMR in cloudy conditions. Enhanced NO2 in the free troposphere commonly appears near polluted urban locations where NO2 produced in the boundary layer may be transported vertically out of the boundary layer and then horizontally away from the source. Signatures of lightning NO2 are also shown throughout low and middle latitude regions in summer months. A profile analysis of our cloud-slicing data indicates signatures of lightning-generated NO2 in the upper troposphere. Comparison of the climatology with simulations from the global modeling initiative (GMI) for cloudy conditions (cloud optical depth less than10) shows similarities in the spatial patterns of continental pollution outflow. However, there are also some differences in the seasonal variation of free-tropospheric NO2 VMRs near highly populated regions and in areas affected by lightning-generated NOx.

  16. Five blind men and the elephant: what can the NASA Aura ozone measurements tell us about stratosphere-troposphere exchange?

    Directory of Open Access Journals (Sweden)

    Q. Tang

    2012-03-01

    Full Text Available We examine whether the individual ozone (O3 measurements from the four Aura instruments can quantify the stratosphere-troposphere exchange (STE flux of O3, an important term of the tropospheric O3 budget. The level 2 (L2 Aura swath data and the nearly coincident ozone sondes for the years 2005–2006 are compared with the 4-D, high-resolution (1° × 1° × 40-layer × 0.5 h model simulation of atmospheric ozone for the same period from the University of California, Irvine chemistry transport model (CTM. The CTM becomes a transfer standard for comparing individual profiles from these five, not-quite-coincident measurements of atmospheric ozone. Even with obvious model discrepancies identified here, the CTM can readily quantify instrument-instrument biases in the tropical upper troposphere and mid-latitude lower stratosphere. In terms of STE processes, all four Aura datasets have some skill in identifying stratosphere-troposphere folds, and we find several cases where both model and measurements see evidence of high-O3 stratospheric air entering the troposphere. In many cases identified in the model, however, the individual Aura profile retrievals in the upper troposphere and lower stratosphere show too much noise, as expected from their low sensitivity and coarse vertical resolution at and below the tropopause. These model-measurement comparisons of individual profiles do provide some level of confidence in the model-derived STE O3 flux, but it will be difficult to integrate this flux from the satellite data alone.

  17. Tropospheric Emission Spectrometer (TES) Data

    Data.gov (United States)

    National Aeronautics and Space Administration — TES focuses on the troposphere, the layer of atmosphere that stretches from the ground to the altitude at which airplanes fly. With very high spectral resolution,...

  18. An Intercomparison of Tropospheric Ozone Retrievals Derived from Two Aura Instruments and Measurements in Western North America in 2006

    Science.gov (United States)

    Doughty, D. C.; Thompson, A. M.; Schoeberl, M. R.; Stajner, I.; Wargan, K.; Hui, W. C. J.

    2011-01-01

    Two recently developed methods for quantifying tropospheric ozone abundances based on Aura data, the Trajectory-enhanced Tropospheric Ozone Residual (TTOR) and an assimilation of Aura data into Goddard Earth Observing System Version 4 (ASM), are compared to ozone measurements from ozonesonde data collected in April-May 2006 during the INTEX Ozonesonde Network Study 2006 (IONS-06) campaign. Both techniques use Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) observations. Statistics on column ozone amounts for both products are presented. In general, the assimilation compares better to sonde integrated ozone to 200 hPa (28.6% difference for TTOR versus 2.7% difference for ASM), and both products are biased low. To better characterize the performance of ASM, ozone profiles based on the assimilation are compared to those from ozonesondes. We noted slight negative biases in the lower troposphere, and slight positive biases in the upper troposphere/lower stratosphere (UT/ LS), where we observed the greatest variability. Case studies were used to further understand ASM performance. We examine one case from 17 April 2006 at Bratt's Lake, Saskatchewan, where geopotential height gradients appear to be related to an underestimation in the ASM in the UT/LS region. A second case, from 21 April 2006 at Trinidad Head, California, is a situation where the overprediction of ozone in the UT/LS region does not appear to be due to current dynamic conditions but seems to be related to uncertainty in the flow pattern and large differences in MLS observations upstream.

  19. Aura OMI observations of changes in SO2 and NO2 emissions at local, regional and global scales

    Science.gov (United States)

    Krotkov, N. A.; McLinden, C. A.; Li, C.; Lamsal, L. N.; Celarier, E. A.; Marchenko, S. V.; Swartz, W.; Bucsela, E. J.; Joiner, J.; Duncan, B. N.; Boersma, K. F.; Veefkind, P.; Levelt, P.; Fioletov, V.; Dickerson, R. R.; He, H.; Lu, Z.; Streets, D. G.

    2015-12-01

    Space-based pollution monitoring from current and planned satellite UV-Vis spectrometers play an increasingly important role in studies of tropospheric chemistry and also air quality applications to help mitigate anthropogenic and natural impacts on sensitive ecosystems, and human health. We present long-term changes in tropospheric SO2 and NO2 over some of the most polluted industrialized regions of the world observed by the Ozone Monitoring Instrument (OMI) onboard NASA's Aura satellite. Using OMI data, we identified about 400 SO2 "hot spots" and estimated emissions from them. In many regions emissions and their ambient pollution levels have decreased significantly, such as over eastern US, Europe and China. OMI observed about 50% reduction in SO2 and NO2 pollution over the North China plain in 2012-2014 that can be attributed to both government efforts to restrain emissions from the power and industrial sectors and the economic slowdown. While much smaller, India's SO2 and NO2 emissions from coal power plants and smelters are growing at a fast pace, increasing by about 200% and 50% from 2005 to 2014. Over Europe and the US OMI-observed trends agree well with those from available in situ measurements of surface concentrations, deposition and emissions data. However, for some regions (e.g., Mexico, Middle East) the emission inventories may be incomplete and OMI can provide emission estimates for missing sources, such as SO2 sources observed over the Persian Gulf. It is essential to continue long-term overlapping satellite data records of air quality with increased spatial and temporal resolution to resolve point pollution sources using oversampling technique. We discuss how Aura OMI pollution measurements and emission estimates will be continued with the US JPSS and European Sentinel series for the next 20 years and further enhanced by the addition of three geostationary UV-VIS instruments.

  20. Global Assimilation of EOS-Aura Data as a Means of Mapping Ozone Distribution in the Lower Stratosphere and Troposphere

    Science.gov (United States)

    Wargan, Krzysztof; Olsen, M.; Douglass, A.; Witte, J.; Strahan, S.; Livesey, N.

    2012-01-01

    Ozone in the lower stratosphere and the troposphere plays an important role in forcing the climate. However, the global ozone distribution in this region is not well known because of the sparse distribution of in-situ data and the poor sensitivity of satellite based observations to the lowermost of the atmosphere. The Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) instruments on EOS-Aura provide information on the total ozone column and the stratospheric ozone profile. This data has been assimilated into NASA s Global Earth Observing System, Version 5 (GEOS-5) data assimilation system (DAS). We will discuss the results of assimilating three years of OMI and MLS data into GEOS-5. This data was assimilated alongside meteorological observations from both conventional sources and satellite instruments. Previous studies have shown that combining observations from these instruments through the Trajectory Tropospheric Ozone Residual methodology (TTOR) or using data assimilation can yield useful, yet low biased, estimates of the tropospheric ozone budget. We show that the assimilated ozone fields in this updated version of GEOS-5 exhibit an excellent agreement with ozone sonde and High Resolution Dynamics Limb Sounder (HIRDLS) data in the lower stratosphere in terms of spatial and temporal variability as well as integrated ozone abundances. Good representation of small-scale vertical features follows from combining the MLS data with the assimilated meteorological fields. We then demonstrate how this information can be used to calculate the Stratosphere - Troposphere Exchange of ozone and its contribution to the tropospheric ozone column in GEOS-5. Evaluations of tropospheric ozone distributions from the assimilation will be made by comparisons with sonde and other in-situ observations.

  1. Tropospheric Emissions: Monitoring of Pollution (TEMPO)

    Science.gov (United States)

    Zoogman, P.; Liu, X.; Suleiman, R. M.; Pennington, W. F.; Flittner, D. E.; Al-Saadi, J. A.; Hilton, B. B.; Nicks, D. K.; Newchurch, M. J.; Carr, J. L.; hide

    2016-01-01

    TEMPO (Tropospheric Emissions: Monitoring of Pollution) was selected in 2012 by NASA as the first Earth Venture Instrument, for launch between 2018 and 2021. It will measure atmospheric pollution for greater North America from space using ultraviolet and visible spectroscopy. TEMPO observes from Mexico City, Cuba, and the Bahamas to the Canadian oil sands, and from the Atlantic to the Pacific, hourly and at high spatial resolution (approximately 2.1 kilometers N/S by 4.4 kilometers E/W at 36.5 degrees N, 100 degrees W). TEMPO provides a tropospheric measurement suite that includes the key elements of tropospheric air pollution chemistry, as well as contributing to carbon cycle knowledge. Measurements are made hourly from geostationary (GEO) orbit, to capture the high variability present in the diurnal cycle of emissions and chemistry that are unobservable from current low-Earth orbit (LEO) satellites that measure once per day. The small product spatial footprint resolves pollution sources at sub-urban scale. Together, this temporal and spatial resolution improves emission inventories, monitors population exposure, and enables effective emission-control strategies. TEMPO takes advantage of a commercial GEO host spacecraft to provide a modest cost mission that measures the spectra required to retrieve ozone (O3), nitrogen dioxide (NO2), sulfur dioxide (SO2), formaldehyde (H2CO), glyoxal (C2H2O2), bromine monoxide (BrO), IO (iodine monoxide),water vapor, aerosols, cloud parameters, ultraviolet radiation, and foliage properties. TEMPO thus measures the major elements, directly or by proxy, in the tropospheric O3 chemistry cycle. Multi-spectral observations provide sensitivity to O3 in the lowermost troposphere, substantially reducing uncertainty in air quality predictions. TEMPO quantifies and tracks the evolution of aerosol loading. It provides these near-real-time air quality products that will be made publicly available. TEMPO will launch at a prime time to be the

  2. Tropospheric Emissions: Monitoring of Pollution (TEMPO)

    Science.gov (United States)

    Chance, Kelly; Liu, Xiong; Suleiman, Raid M.; Flittner, David E.; Al-Saadi, Jassim; Janz, Scott J.

    2014-06-01

    TEMPO, selected by NASA as the first Earth Venture Instrument, will measure atmospheric pollution for greater North America from space using ultraviolet and visible spectroscopy. TEMPO measures from Mexico City to the Canadian oil sands, and from the Atlantic to the Pacific, hourly and at high spatial resolution. TEMPO provides a tropospheric measurement suite that includes the key elements of tropospheric air pollution chemistry. Measurements are from geostationary (GEO) orbit, to capture the inherent high variability in the diurnal cycle of emissions and chemistry. The small product spatial footprint resolves pollution sources at sub-urban scale. Together, this temporal and spatial resolution improves emission inventories, monitors population exposure, and enables effective emission-control strategies. TEMPO takes advantage of a GEO host spacecraft to provide a modest-cost mission that measures the spectra required to retrieve O3, NO2, SO2, H2CO, C2H2O2, H2O, aerosols, cloud parameters, and UVB radiation. TEMPO thus measures the major elements, directly or by proxy, in the tropospheric O3 chemistry cycle. Multi-spectral observations provide sensitivity to O3 in the lowermost troposphere, reducing uncertainty in air quality predictions by 50 %. TEMPO quantifies and tracks the evolution of aerosol loading. It provides near-real-time air quality products that will be made widely, publicly available. TEMPO makes the first tropospheric trace gas measurements from GEO, by building on the heritage of five spectrometers flown in low-earth-orbit (LEO). These LEO instruments measure the needed spectra, although at coarse spatial and temporal resolutions, to the precisions required for TEMPO and use retrieval algorithms developed for them by TEMPO Science Team members and currently running in operational environments. This makes TEMPO an innovative use of a well-proven technique, able to produce a revolutionary data set. TEMPO provides much of the atmospheric measurement

  3. Tropospheric Emissions: Monitoring of Pollution Overview

    Science.gov (United States)

    Chance, Kelly; Liu, Xiong; Suleiman, Raid M.; Flittner, David; Al-Saadi, Jay; Janz, Scott

    2015-01-01

    TEMPO is now well into its implementation phase, having passed both its Key Decision Point C and the Critical Design Review (CDR) for the instrument. The CDR for the ground systems will occur in March 2016 and the CDR for the Mission component at a later date, after the host spacecraft has been selected. TEMPO is on schedule to measure atmospheric pollution for greater North America from space using ultraviolet and visible spectroscopy. TEMPO measures from Mexico City to the Canadian oil sands, and from the Atlantic to the Pacific, hourly and at high spatial resolution. TEMPO provides a tropospheric measurement suite that includes the key elements of tropospheric air pollution chemistry. Measurements are from geostationary (GEO) orbit, to capture the inherent high variability in the diurnal cycle of emissions and chemistry. The small product spatial footprint resolves pollution sources at sub-urban scale. Together, this temporal and spatial resolution improves emission inventories, monitors population exposure, and enables effective emission-control strategies. TEMPO takes advantage of a GEO host spacecraft to provide a modest cost mission that measures the spectra required to retrieve O3, NO2, SO2, H2CO, C2H2O2, H2O, aerosols, cloud parameters, and UVB radiation. TEMPO thus measures the major elements, directly or by proxy, in the tropospheric O3 chemistry cycle. Multi-spectral observations provide sensitivity to O3 in the lowermost troposphere, substantially reducing uncertainty in air quality predictions by 50 percent. TEMPO quantifies and tracks the evolution of aerosol loading. It provides near-real-time air quality products that will be made widely, publicly available. TEMPO provides much of the atmospheric measurement capability recommended for GEO-CAPE in the 2007 National Research Council Decadal Survey, Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond. Instruments from Europe (Sentinel 4) and Asia (GEMS) will

  4. Tropospheric emissions: Monitoring of pollution (TEMPO)

    Science.gov (United States)

    Zoogman, P.; Liu, X.; Suleiman, R. M.; Pennington, W. F.; Flittner, D. E.; Al-Saadi, J. A.; Hilton, B. B.; Nicks, D. K.; Newchurch, M. J.; Carr, J. L.; Janz, S. J.; Andraschko, M. R.; Arola, A.; Baker, B. D.; Canova, B. P.; Chan Miller, C.; Cohen, R. C.; Davis, J. E.; Dussault, M. E.; Edwards, D. P.; Fishman, J.; Ghulam, A.; González Abad, G.; Grutter, M.; Herman, J. R.; Houck, J.; Jacob, D. J.; Joiner, J.; Kerridge, B. J.; Kim, J.; Krotkov, N. A.; Lamsal, L.; Li, C.; Lindfors, A.; Martin, R. V.; McElroy, C. T.; McLinden, C.; Natraj, V.; Neil, D. O.; Nowlan, C. R.; O`Sullivan, E. J.; Palmer, P. I.; Pierce, R. B.; Pippin, M. R.; Saiz-Lopez, A.; Spurr, R. J. D.; Szykman, J. J.; Torres, O.; Veefkind, J. P.; Veihelmann, B.; Wang, H.; Wang, J.; Chance, K.

    2017-01-01

    TEMPO was selected in 2012 by NASA as the first Earth Venture Instrument, for launch between 2018 and 2021. It will measure atmospheric pollution for greater North America from space using ultraviolet and visible spectroscopy. TEMPO observes from Mexico City, Cuba, and the Bahamas to the Canadian oil sands, and from the Atlantic to the Pacific, hourly and at high spatial resolution ( 2.1 km N/S×4.4 km E/W at 36.5°N, 100°W). TEMPO provides a tropospheric measurement suite that includes the key elements of tropospheric air pollution chemistry, as well as contributing to carbon cycle knowledge. Measurements are made hourly from geostationary (GEO) orbit, to capture the high variability present in the diurnal cycle of emissions and chemistry that are unobservable from current low-Earth orbit (LEO) satellites that measure once per day. The small product spatial footprint resolves pollution sources at sub-urban scale. Together, this temporal and spatial resolution improves emission inventories, monitors population exposure, and enables effective emission-control strategies. TEMPO takes advantage of a commercial GEO host spacecraft to provide a modest cost mission that measures the spectra required to retrieve ozone (O3), nitrogen dioxide (NO2), sulfur dioxide (SO2), formaldehyde (H2CO), glyoxal (C2H2O2), bromine monoxide (BrO), IO (iodine monoxide), water vapor, aerosols, cloud parameters, ultraviolet radiation, and foliage properties. TEMPO thus measures the major elements, directly or by proxy, in the tropospheric O3 chemistry cycle. Multi-spectral observations provide sensitivity to O3 in the lowermost troposphere, substantially reducing uncertainty in air quality predictions. TEMPO quantifies and tracks the evolution of aerosol loading. It provides these near-real-time air quality products that will be made publicly available. TEMPO will launch at a prime time to be the North American component of the global geostationary constellation of pollution monitoring

  5. Validation of Aura Microwave Limb Sounder O3 and CO Observations in the Upper Troposphere and Lower Stratosphere

    Science.gov (United States)

    Livesey, N. J.; Filipiak, M. J.; Froidevaux, L.; Read, W. G.; Lambert, A.; Santee, J. L.; Jiang, J. H.; Pumphrey, H. C.; Waters, J. W.; Cofield, R. E.; hide

    2008-01-01

    Global satellite observations of ozone and carbon monoxide from the Microwave Limb Sounder (MLS) on the EOS Aura spacecraft are discussed with emphasis on those observations in the 2 15 - 100 hPa region (the upper troposphere and lower stratosphere). The precision, resolution and accuracy of the data produced by the MLS "version 2.2" processing algorithms are discussed and quantified. O3 accuracy is estimated at approx.40 ppbv +5% (approx.20 ppbv +20% at 215 hPa) while the CO accuracy is estimated at approx.30 ppbv +30% for pressures of 147 hPa and less. Comparisons with expectations and other observations show good agreements for the O3 product, generally consistent with the systematic errors quoted above. In the case of COY a persistent factor of approx.2 high bias is seen at 215 hPa. However, the morphology is shown to be realistic, consistent with raw MLS radiance data, and useful for scientific study. The MLS CO data at higher altitudes are shown to be consistent with other observations.

  6. Validation of Aura Microwave Limb Sounder O3 and CO Observations in the Upper Troposphere and Lower Stratosphere

    Science.gov (United States)

    Livesey, N. J.; Filipiak, M. J.; Froidevaux, L.; Read, W. G.; Lambert, A.; Santee, J. L.; Jiang, J. H.; Pumphrey, H. C.; Waters, J. W.; Cofield, R. E.; Cuddy, D. T.; Daffer, W. H.; Drouin, B. J.; Fuller, R. A.; Jarnot, R. F.; Jiang, Y. B.; Knosp, B. W.; Li, Q. B.; Perun, V. S.; Schwartz, M. J.; Snyder, W. V.; Stek, P. C.; Thurstans, R. P.; Wagner, P. A.; Avery, M.

    2008-01-01

    Global satellite observations of ozone and carbon monoxide from the Microwave Limb Sounder (MLS) on the EOS Aura spacecraft are discussed with emphasis on those observations in the 2 15 - 100 hPa region (the upper troposphere and lower stratosphere). The precision, resolution and accuracy of the data produced by the MLS "version 2.2" processing algorithms are discussed and quantified. O3 accuracy is estimated at approx.40 ppbv +5% (approx.20 ppbv +20% at 215 hPa) while the CO accuracy is estimated at approx.30 ppbv +30% for pressures of 147 hPa and less. Comparisons with expectations and other observations show good agreements for the O3 product, generally consistent with the systematic errors quoted above. In the case of COY a persistent factor of approx.2 high bias is seen at 215 hPa. However, the morphology is shown to be realistic, consistent with raw MLS radiance data, and useful for scientific study. The MLS CO data at higher altitudes are shown to be consistent with other observations.

  7. Monitoring Air Quality from Space using AURA Data

    Science.gov (United States)

    Gleason, James F.; Chance, Kelly V.; Fishman, Jack; Torres, Omar; Veefkind, Pepijn

    2003-01-01

    Measurements from the Earth Observing System (EOS) AURA mission will provide a unique perspective on air quality monitoring. Ozone, nitrogen dioxide, formaldehyde and aerosols from the Ozone Monitoring Instrument (OMI) and carbon monoxide from the Tropospheric Emission Spectrometer (TES) will be simultaneously measured with the spatial resolution and coverage needed for improving our understanding of air quality. AURA data products useful for air quality monitoring will be given.

  8. Validation of Aura MLS retrievals of temperature, water vapour and ozone in the upper troposphere and lower-middle stratosphere over the Tibetan Plateau during boreal summer

    Science.gov (United States)

    Yan, Xiaolu; Wright, Jonathon S.; Zheng, Xiangdong; Livesey, Nathaniel J.; Vömel, Holger; Zhou, Xiuji

    2016-08-01

    We validate Aura Microwave Limb Sounder (MLS) version 3 (v3) and version 4 (v4) retrievals of summertime temperature, water vapour and ozone in the upper troposphere and lower-middle stratosphere (UTLS; 10-316 hPa) against balloon soundings collected during the Study of Ozone, Aerosols and Radiation over the Tibetan Plateau (SOAR-TP). Mean v3 and v4 profiles of temperature, water vapour and ozone in this region during the measurement campaigns are almost identical through most of the stratosphere (10-68 hPa), but differ in several respects in the upper troposphere and tropopause layer. Differences in v4 relative to v3 include slightly colder mean temperatures from 100 to 316 hPa, smaller mean water vapour mixing ratios in the upper troposphere (215-316 hPa) and a more vertically homogeneous profile of mean ozone mixing ratios below the climatological tropopause (100-316 hPa). These changes substantially improve agreement between ozonesondes and MLS ozone retrievals in the upper troposphere, but slightly worsen existing cold and dry biases at these levels. Aura MLS temperature profiles contain significant cold biases relative to collocated temperature measurements in several layers of the lower-middle stratosphere and in the upper troposphere. MLS retrievals of water vapour volume mixing ratio generally compare well with collocated measurements, excepting a substantial dry bias (-32 ± 11 % in v4) that extends through most of the upper troposphere (121-261 hPa). MLS retrievals of ozone volume mixing ratio are biased high relative to collocated ozonesondes in the stratosphere (18-83 hPa), but are biased low at 100 hPa. The largest relative biases in ozone retrievals (approximately +70 %) are located at 83 hPa. MLS v4 offers substantial benefits relative to v3, particularly with respect to water vapour and ozone. Key improvements include larger data yields, reduced noise in the upper troposphere and smaller fluctuations in the bias profile at pressures larger than 100

  9. SVD analysis of Aura TES spectral residuals

    Science.gov (United States)

    Beer, Reinhard; Kulawik, Susan S.; Rodgers, Clive D.; Bowman, Kevin W.

    2005-01-01

    Singular Value Decomposition (SVD) analysis is both a powerful diagnostic tool and an effective method of noise filtering. We present the results of an SVD analysis of an ensemble of spectral residuals acquired in September 2004 from a 16-orbit Aura Tropospheric Emission Spectrometer (TES) Global Survey and compare them to alternative methods such as zonal averages. In particular, the technique highlights issues such as the orbital variation of instrument response and incompletely modeled effects of surface emissivity and atmospheric composition.

  10. Tropospheric methanol observations from space: constraints on the seasonality of biogenic emissions

    Science.gov (United States)

    Wells, K. C.; Millet, D. B.; Cady-Pereira, K. E.; Shephard, M. W.; Xiao, Y.; Razavi, A.; Clerbaux, C.

    2011-12-01

    Methanol is the most abundant non-methane organic compound in the atmosphere, and is an important precursor of atmospheric pollutants such as CO and formaldehyde. The recent development of methanol retrievals from nadir-viewing satellite-based platforms offers powerful new information for quantifying methanol emissions on a global scale. This study uses methanol observations from the Tropospheric Emission Spectrometer (TES) on the Aura satellite and the Infrared Atmospheric Sounding Interferometer (IASI) on the MetOp-A satellite, in conjunction with aircraft data, to investigate methanol emissions from major plant functional types in the GEOS-Chem global chemical transport model (driven with MEGAN biogenic emissions). We first evaluate the TES methanol retrievals by comparing to simulation results and flight observations from several North American field campaigns. Results show that the retrieval performs well when the degrees of freedom for signal are above 0.5. We analyze one full year of TES and IASI observations and find a persistent model underestimate in springtime, and make recommendations for an improved seasonal distribution of biogenic methanol emissions over temperate regions of the globe.

  11. An Ozone Profile Climatology based on Ozone-sondes and AURA MLS Data with Added Profiles for Ozone Hole Conditions and Wave One Parameterization for Tropical Tropospheric Ozone.

    Science.gov (United States)

    Labow, G. J.; Ziemke, J. R.; Stauffer, R. M.; McPeters, R. D.

    2016-12-01

    An updated ozone profile climatology has been created for use in satellite and/or ground based ozone retrievals. This climatology was formed by combining 12 years of data from the Microwave Limb Sounder (MLS) with data from balloon sondes. The MLS instrument on Aura has excellent latitude coverage and measures ozone daily from the upper troposphere to the lower mesosphere at 3.5 km resolution. This climatology consists of monthly average ozone profiles for ten degree latitude zones covering pressure altitudes (Z* pressure altitude coordinates) from 0 to 65 km. Ozone below 8 km (below 13 km at tropical latitudes) is based on ozonesondes, while ozone above 16 km (21 km at tropical latitudes) is based on MLS measurements. Sonde and MLS (V4.2) data are blended in the transition region. This climatology features two distinct profiles for the southern hemisphere (60-90S) from August to December. The profiles labeled "Hole" correspond to measurements taken inside the polar vortex while the profiles in the file labeled "No Hole" are averages taken from measurements outside the vortex. The filtering criteria for determining a profile inside/outside the vortex was done by analyzing the 50hPa ozone values. The 50hPa values are where the chemical depletion process is greatest and thus are a good indicator of the vortex boundary. We also include a representation of the observed zonal wave one tropospheric ozone feature in the tropics. Because ozonesonde stations are sparse in this region, we derive the tropospheric column ozone residual by subtracting the MLS stratospheric column from the Ozone Monitoring Instrument (OMI) total column. We then combine the result with ozonesonde data. A function is fitted to the data in several dimensions to better depict the climatology of both the tropospheric column and vertical distribution of tropospheric ozone in the tropics.

  12. Emission Ratios for Ammonia and Formic Acid and Observations of Peroxy Acetyl Nitrate (PAN and Ethylene in Biomass Burning Smoke as Seen by the Tropospheric Emission Spectrometer (TES

    Directory of Open Access Journals (Sweden)

    Vivienne H. Payne

    2011-11-01

    Full Text Available We use the Tropospheric Emission Spectrometer (TES aboard the NASA Aura satellite to determine the concentrations of the trace gases ammonia (NH3 and formic acid (HCOOH within boreal biomass burning plumes, and present the first detection of peroxy acetyl nitrate (PAN and ethylene (C2H4 by TES. We focus on two fresh Canadian plumes observed by TES in the summer of 2008 as part of the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS-B campaign. We use TES retrievals of NH3 and HCOOH within the smoke plumes to calculate their emission ratios (1.0% ± 0.5% and 0.31% ± 0.21%, respectively relative to CO for these Canadian fires. The TES derived emission ratios for these gases agree well with previous aircraft and satellite estimates, and can complement ground-based studies that have greater surface sensitivity. We find that TES observes PAN mixing ratios of ~2 ppb within these mid-tropospheric boreal biomass burning plumes when the average cloud optical depth is low ( < 0.1 and that TES can detect C2H4 mixing ratios of ~2 ppb in fresh biomass burning smoke plumes.

  13. Extending the satellite data record of tropospheric ozone profiles from Aura-TES to MetOp-IASI

    Directory of Open Access Journals (Sweden)

    H. Oetjen

    2014-07-01

    Full Text Available We apply the Tropospheric Emission Spectrometer (TES ozone retrieval algorithm to Infrared Atmospheric Sounding Instrument (IASI radiances and characterise the uncertainties and information content of the retrieved ozone profiles. This study focuses on mid-latitudes for the year 2008. We validate our results by comparing the IASI ozone profiles to ozone sondes. In the sonde comparisons, we find a positive bias in the IASI ozone profiles in the UTLS region of up to 14% on average. For the described cases, the degrees of freedom for signal are on average 3.2, 0.3, 0.8, and 0.9 for the columns 0 km–top of atmosphere, (0–6 km, (0–11 km, and (8–16 km, respectively. We find that our biases with respect to sondes and our degrees of freedom for signal for ozone are comparable to previously published results from other IASI ozone algorithms. In addition to evaluating biases, we validate the retrieval errors by comparing predicted errors to the sample covariance matrix of the IASI observations themselves. For the predicted vs. empirical error comparison, we find that these errors are consistent and that the measurement noise and the interference of temperature and water vapour on the retrieval together mostly explain the empirically derived random errors. In general, the precision of the IASI ozone profiles is better than 20%.

  14. Global free tropospheric NO2 abundances derived using a cloud slicing technique applied to satellite observations from the Aura Ozone Monitoring Instrument (OMI

    Directory of Open Access Journals (Sweden)

    S. Choi

    2014-01-01

    Full Text Available We derive free-tropospheric NO2 volume mixing ratios (VMRs and stratospheric column amounts of NO2 by applying a cloud slicing technique to data from the Ozone Monitoring Instrument (OMI on the Aura satellite. In the cloud-slicing approach, the slope of the above-cloud NO2 column vs. the cloud scene pressure is proportional to the NO2 VMR. In this work, we use a sample of nearby OMI pixel data from a single orbit for the linear fit. The OMI data include cloud scene pressures from the rotational-Raman algorithm and above-cloud NO2 vertical column density (VCD (defined as the NO2 column from the cloud scene pressure to the top-of-the-atmosphere from a differential optical absorption spectroscopy (DOAS algorithm. Estimates of stratospheric column NO2 are obtained by extrapolating the linear fits to the tropopause. We compare OMI-derived NO2 VMRs with in situ aircraft profiles measured during the NASA Intercontinental Chemical Transport Experiment Phase B (INTEX-B campaign in 2006. The agreement is generally within the estimated uncertainties when appropriate data screening is applied. We then derive a global seasonal climatology of free-tropospheric NO2 VMR in cloudy conditions. Enhanced NO2 in the free troposphere commonly appears near polluted urban locations where NO2 produced in the boundary layer may be transported vertically out of the boundary layer and then horizontally away from the source. Signatures of lightning NO2 are also shown throughout low and middle latitude regions in summer months. A profile analysis of our cloud slicing data indicates signatures of uplifted and transported anthropogenic NO2 in the middle troposphere as well as lightning-generated NO2 in the upper troposphere. Comparison of the climatology with simulations from the Global Modeling Initiative (GMI for cloudy conditions (cloud optical thicknesses > 10 shows similarities in the spatial patterns of continental pollution outflow. However, there are also some

  15. Global Free Tropospheric NO2 Abundances Derived Using a Cloud Slicing Technique Applied to Satellite Observations from the Aura Ozone Monitoring Instrument (OMI)

    Science.gov (United States)

    Choi, S.; Joiner, J.; Choi, Y.; Duncan, B. N.; Bucsela, E.

    2014-01-01

    We derive free-tropospheric NO2 volume mixing ratios (VMRs) and stratospheric column amounts of NO2 by applying a cloud slicing technique to data from the Ozone Monitoring Instrument (OMI) on the Aura satellite. In the cloud-slicing approach, the slope of the above-cloud NO2 column versus the cloud scene pressure is proportional to the NO2 VMR. In this work, we use a sample of nearby OMI pixel data from a single orbit for the linear fit. The OMI data include cloud scene pressures from the rotational-Raman algorithm and above-cloud NO2 vertical column density (VCD) (defined as the NO2 column from the cloud scene pressure to the top-of-the-atmosphere) from a differential optical absorption spectroscopy (DOAS) algorithm. Estimates of stratospheric column NO2 are obtained by extrapolating the linear fits to the tropopause. We compare OMI-derived NO2 VMRs with in situ aircraft profiles measured during the NASA Intercontinental Chemical Transport Experiment Phase B (INTEX-B) campaign in 2006. The agreement is generally within the estimated uncertainties when appropriate data screening is applied. We then derive a global seasonal climatology of free-tropospheric NO2 VMR in cloudy conditions. Enhanced NO2 in the free troposphere commonly appears near polluted urban locations where NO2 produced in the boundary layer may be transported vertically out of the boundary layer and then horizontally away from the source. Signatures of lightning NO2 are also shown throughout low and middle latitude regions in summer months. A profile analysis of our cloud slicing data indicates signatures of uplifted and transported anthropogenic NO2 in the middle troposphere as well as lightning-generated NO2 in the upper troposphere. Comparison of the climatology with simulations from the Global Modeling Initiative (GMI) for cloudy conditions (cloud optical thicknesses > 10) shows similarities in the spatial patterns of continental pollution outflow. However, there are also some differences in

  16. A Tropospheric Emission Spectrometer HDO/H2O Retrieval Simulator for Climate Models

    Science.gov (United States)

    Field, R. D.; Risi, C.; Schmidt, G. A.; Worden, J.; Voulgarakis, A.; LeGrande, A. N.; Sobel, A. H.; Healy, R. J.

    2012-01-01

    Retrievals of the isotopic composition of water vapor from the Aura Tropospheric Emission Spectrometer (TES) have unique value in constraining moist processes in climate models. Accurate comparison between simulated and retrieved values requires that model profiles that would be poorly retrieved are excluded, and that an instrument operator be applied to the remaining profiles. Typically, this is done by sampling model output at satellite measurement points and using the quality flags and averaging kernels from individual retrievals at specific places and times. This approach is not reliable when the model meteorological conditions influencing retrieval sensitivity are different from those observed by the instrument at short time scales, which will be the case for free-running climate simulations. In this study, we describe an alternative, categorical approach to applying the instrument operator, implemented within the NASA GISS ModelE general circulation model. Retrieval quality and averaging kernel structure are predicted empirically from model conditions, rather than obtained from collocated satellite observations. This approach can be used for arbitrary model configurations, and requires no agreement between satellite-retrieved and model meteorology at short time scales. To test this approach, nudged simUlations were conducted using both the retrieval-based and categorical operators. Cloud cover, surface temperature and free-tropospheric moisture content were the most important predictors of retrieval quality and averaging kernel structure. There was good agreement between the D fields after applying the retrieval-based and more detailed categorical operators, with increases of up to 30 over the ocean and decreases of up to 40 over land relative to the raw model fields. The categorical operator performed better over the ocean than over land, and requires further refinement for use outside of the tropics. After applying the TES operator, ModelE had D biases of 8

  17. Interrelated variations of O3, CO and deep convection in the tropical/subtropical upper troposphere observed by the Aura Microwave Limb Sounder (MLS during 2004–2011

    Directory of Open Access Journals (Sweden)

    L. Froidevaux

    2012-07-01

    Full Text Available The interrelated geographical and temporal variability seen in more than seven years of tropical and subtropical upper tropospheric (215 hPa ozone, carbon monoxide and cloud ice water content (IWC observations by the Aura Microwave Limb Sounder (MLS are presented. Observed ozone abundances and their variability (geographical and temporal agree to within 10–15 ppbv with records from sonde observations. MLS complements these (and other observations with global coverage and simultaneous measurements of related parameters. Previously-reported phenomena such as the ozone "wave one" feature are clearly seen in the MLS observations, as is a double peak in ozone abundance over tropical East Africa, with enhanced abundances in both May to June and September to November. While repeatable seasonal cycles are seen in many regions, they are often accompanied by significant interannual variability. Ozone seasonal cycles in the southern tropics and subtropics tend to be more distinct (i.e., annually repeatable than in the northern. By contrast, carbon monoxide shows distinct seasonal cycles in many northern subtropical regions, notably from India to the Eastern Pacific. Deep convection (as indicated by large values of IWC is typically associated with reductions in upper tropospheric ozone. Convection over polluted regions is seen to significantly enhance upper tropospheric carbon monoxide. While some regions show statistically significant correlations among ozone, carbon monoxide and IWC, simple correlations fall well short of accounting for the observed variability. The observed interrelated variations and metrics of annual and interannual variability described here represent a new resource for validation of atmospheric chemistry models.

  18. Interrelated variations of O3, CO and deep convection in the tropical/subtropical upper troposphere observed by the Aura Microwave Limb Sounder (MLS during 2004–2011

    Directory of Open Access Journals (Sweden)

    L. Froidevaux

    2013-01-01

    Full Text Available The interrelated geographic and temporal variability seen in more than seven years of tropical and subtropical upper tropospheric (215 hPa ozone, carbon monoxide and cloud ice water content (IWC observations by the Aura Microwave Limb Sounder (MLS are presented. Observed ozone abundances and their variability (geographic and temporal agree to within 10–15 ppbv with records from sonde observations. MLS complements these (and other observations with global coverage and simultaneous measurements of related parameters. Previously-reported phenomena such as the ozone "wave one" feature are clearly seen in the MLS observations, as is a double peak in ozone abundance over tropical East Africa, with enhanced abundances in both May to June and September to November. While repeatable seasonal cycles are seen in many regions, they are often accompanied by significant interannual variability. Ozone seasonal cycles in the southern tropics and subtropics tend to be more distinct (i.e., annually repeatable than in the northern. By contrast, carbon monoxide shows distinct seasonal cycles in many northern subtropical regions, notably from India to the Eastern Pacific. Deep convection (as indicated by large values of IWC is typically associated with reductions in upper tropospheric ozone. Convection over polluted regions is seen to significantly enhance upper tropospheric carbon monoxide. While some regions show statistically significant correlations among ozone, carbon monoxide and IWC, simple correlations fall well short of accounting for the observed variability. The observed interrelated variations and metrics of annual and interannual variability described here represent a new resource for validation of atmospheric chemistry models.

  19. Evaluation of a regional air quality forecast model for tropospheric NO2 columns using the OMI/Aura satellite tropospheric NO2 product

    Directory of Open Access Journals (Sweden)

    J. K. Vaughan

    2010-09-01

    Full Text Available Results from a regional air quality forecast model, AIRPACT-3, are compared to OMI tropospheric NO2 integrated column densities for an 18 month period over the Pacific Northwest. AIRPACT column densities are well correlated (r=0.75 to cloud-free (2 for monthly averages without wildfires, but are poorly correlated (r=0.21 with significant model over-predictions for months with wildfires when OMI and AIRPACT are compared over the entire domain. AIRPACT predicts higher NO2 in some northwestern US urban areas, and lower NO2 in the Vancouver, BC urban area, when compared to OMI. Model results are spatially averaged to the daily OMI swath. The Dutch KNMI (DOMINO and NASA (Standard Product retrievals of tropospheric NO2 from OMI (Collection-3 are compared. The NASA product is shown to be significantly different than the KNMI tropospheric NO2 product. The average difference in tropospheric columns, after applying the averaging kernels of the respective products to the model results, is shown to be larger in the summer (±50% than winter (±20%.

  20. Updated SO2 Emission Estimates over China using OMI/Aura Observations and the CHIMERE CTM

    Science.gov (United States)

    van der A, R. J.; Balis, D.; Koukouli, M.; Theys, N.; Ding, J.; Zyrichidou, I.; Mijling, B.

    2016-12-01

    As part of EU FP7 Monitoring and Assessment of Regional air quality in China using space Observations, Project Of Long-term sino-european co-Operation, MarcoPolo, project, http://www.marcopolo.eu/, updated sulphur dioxide, SO2, emissions for the time period 2005 to 2015 inclusive are presented here. Monthly mean OMI/Aura anthropogenic SO2, observations over Eastern China for the domain 102°E to 132°E and from 15°N to 55°N form the basis of the new emission inventory, which is provided on a spatial resolution of 0.25°x0.25°. The 2010 Multi-resolution Emission Inventory for China (MEIC), http://www.meicmodel.org/. SO2 emissions, in Mg/month, form the baseline apriori inventory, coupled with the multi-scale model for air quality forecasting and simulation, CHIMERE, http://www.lmd.polytechnique.fr/chimere/, v2013b, which is providing the SO2 field. The pre-2010 trend in resulting emissions show that these appear to be stable in time, with a slight negative, possibly not significant, trend nonetheless; from the monthly mean aposteriori emissions, for the entire domain, pre-2010, the change appears to be of the order of -0.51±0.38Tg, whereas post-2010, -1.64±0.37Tg. From the seasonal emissions, those estimates remain similar at -0.34±0.49Tg and -1.26±0.33Tg respectively. The largest differences between apriori and aposteriori become vastly significant from year 2014 onwards, confirming similar studies that monitor the decrease in SO2 emissions over China from space.

  1. Status of Tropospheric Emissions: Monitoring of Pollution (TEMPO)

    Science.gov (United States)

    Chance, K.; Liu, X.; Suleiman, R. M.; Flittner, D. E.; Al-Saadi, J. A.; Janz, S. J.

    2016-12-01

    TEMPO is now in the Assembly, Integration and Test (AI&T) phase, having passed its Key Decision Point C, Critical Design Reviews (CDRs) for the instrument and the ground systems, and the Test Readiness Review (TRR). The TEMPO instrument is scheduled for delivery in August 2017. The request for proposals to host TEMPO on a commercial geostationary satellite is scheduled for release by May 2017, with host selection hopefully completed by the end of calendar 2017. TEMPO is thus on schedule to measure atmospheric pollution for greater North America from space using ultraviolet and visible spectroscopy. TEMPO measures from Mexico City and Cuba to the Canadian oil sands, and from the Atlantic to the Pacific, hourly and at high spatial resolution. It provides a measurement suite that includes the key elements of tropospheric air pollution chemistry. Measurements are from geostationary (GEO) orbit, to capture the high variability in the diurnal cycle of emissions and chemistry. The small spatial footprint resolves pollution sources at sub-urban scale. Together, this temporal and spatial resolution improves emission inventories, monitors population exposure, and enables effective emission-control strategies.TEMPO takes advantage of a GEO host spacecraft to provide a mission that measures the spectra required to retrieve O3, NO2, SO2, H2CO, C2H2O2, H2O, aerosols, cloud parameters, and UVB radiation. TEMPO thus measures the major elements, directly or by proxy, in the tropospheric O3 chemistry cycle. Multi-spectral observations provide sensitivity to O3 in the lowermost troposphere, substantially reducing uncertainty in air quality predictions. TEMPO quantifies and tracks the evolution of aerosol loading. It provides near-real-time air quality products that will be made widely, publicly available.TEMPO provides much of the atmospheric measurement capability recommended for GEO-CAPE in the 2007 National Research Council Decadal Survey, Earth Science and Applications from Space

  2. Analysis of CO in the tropical troposphere using Aura satellite data and the GEOS-Chem model: insights into transport characteristics of the GEOS meteorological products

    Directory of Open Access Journals (Sweden)

    Junhua Liu

    2010-12-01

    Full Text Available We use the GEOS-Chem chemistry-transport model (CTM to interpret the spatial and temporal variations of tropical tropospheric CO observed by the Microwave Limb Sounder (MLS and the Tropospheric Emission Spectrometer (TES. In so doing, we diagnose and evaluate transport in the GEOS-4 and GEOS-5 assimilated meteorological fields that drive the model, with a particular focus on vertical mixing at the end of the dry season when convection moves over the source regions. The results indicate that over South America, deep convection in both GEOS-4 and GEOS-5 decays at too low an altitude early in the wet season, and the source of CO from isoprene in the model (MEGAN v2.1 is too large, causing a lag in the model's seasonal maximum of CO compared to MLS CO in the upper troposphere (UT. TES and MLS data reveal problems with excessive transport of CO to the eastern equatorial Pacific and lofting in the ITCZ in August and September, particularly in GEOS-4. Over southern Africa, GEOS-4 and GEOS-5 simulations match the phase of the observed CO variation from the lower troposphere (LT to the UT fairly well, although the magnitude of the seasonal maximum is underestimated considerably due to low emissions in the model. A sensitivity run with increased emissions leads to improved agreement with observed CO in the LT and middle troposphere (MT, but the amplitude of the seasonal variation is too high in the UT in GEOS-4. Difficulty in matching CO in the LT and UT implies there may be overly vigorous vertical mixing in GEOS-4 early in the wet season. Both simulations and observations show a time lag between the peak in fire emissions (July and August and in CO (September and October. We argue that it is caused by the prevailing subsidence in the LT until convection moves south in September, as well as the low sensitivity of TES data in the LT over the African Plateau. The MLS data suggest that too much CO has been transported from fires in northern Africa to the UT

  3. Utilizing Tropospheric Emission Spectrometer (TES) Special Observations to Study Air Quality Over Megacities: A Case Study of Mexico City

    Science.gov (United States)

    Osterman, G. B.; Neu, J. L.; Cady-Pereira, K.; Fu, D.; Payne, V.; Pfister, G.

    2016-12-01

    Since the beginning of 2013, the Tropospheric Emission Spectrometer (TES) on the NASA Aura spacecraft has been making special "transect" observations over 19 large cities across the globe. In all there are over 50 transect observations of each city, allowing for studying the chemistry of the troposphere during different seasons and differing atmospheric conditions. The cities that have been observed include, Beijing, Delhi and Mexico City. In addition, the TES group at JPL has been developing new data products using combined radiances from other satellite instruments. They have produced an ozone data product using a combination of TES and Ozone Monitoring Instrument (OMI) radiances. There has also been progress in creating an ozone product from combining OMI and Atmospheric Infrared Sounder (AIRS) radiances using the TES retrieval framework. This product offers the possibility of better spatial coverage than the TES or TES/OMI products. We have selected an observation from October 13, 2013 over Mexico City for doing a case study where high values of ozone were seen in the lower troposphere in retrievals from TES and TES/OMI. Other trace gases measured by TES, carbon monoxide, methanol, and formic acid were also enhanced over the city. TES was also able to capture downwind conditions where the trace gases were no longer enhanced except for formic acid and peroxyacetyl nitrate which showed elevated values. We will utilize trajectory analysis, the TES data as well as combined TES-OMI retrievals, the new combined AIRS-OMI retrievals of ozone to examine this case in more detail to understand possible broader scale effects of Mexico City pollution. Model results will be utilized to provide further context in understanding the atmospheric conditions being studied. We feel the TES special observations of megacities will provide an opportunity to study the effects of local sources versus broader regional sources on pollutions of these large cities.

  4. Emission sources contributing to tropospheric ozone over Equatorial Africa during the summer monsoon

    Science.gov (United States)

    Bouarar, I.; Law, K. S.; Pham, M.; Liousse, C.; Schlager, H.; Hamburger, T.; Reeves, C. E.; Cammas, J.-P.; Nédéléc, P.; Szopa, S.; Ravegnani, F.; Viciani, S.; D'Amato, F.; Ulanovsky, A.; Richter, A.

    2011-12-01

    A global chemistry-climate model LMDz_INCA is used to investigate the contribution of African and Asian emissions to tropospheric ozone over Central and West Africa during the summer monsoon. The model results show that ozone in this region is most sensitive to lightning NOx and to Central African biomass burning emissions. However, other emission categories also contribute significantly to regional ozone. The maximum ozone changes due to lightning NOx occur in the upper troposphere between 400 hPa and 200 hPa over West Africa and downwind over the Atlantic Ocean. Biomass burning emissions mainly influence ozone in the lower and middle troposphere over Central Africa, and downwind due to westward transport. Biogenic emissions of volatile organic compounds, which can be uplifted from the lower troposphere to higher altitudes by the deep convection that occurs over West Africa during the monsoon season, lead to maximum ozone changes in the lower stratosphere region. Soil NOx emissions over the Sahel region make a significant contribution to ozone in the lower troposphere. In addition, convective uplift of these emissions and subsequent ozone production are also an important source of ozone in the upper troposphere over West Africa. Concerning African anthropogenic emissions, they only make a small contribution to ozone compared to the other emission categories. The model results indicate that most ozone changes due to African emissions occur downwind, especially over the Atlantic Ocean, far from the emission regions. The import of Asian emissions also makes a considerable contribution to ozone concentrations above 150 hPa and has to be taken into account in studies of the ozone budget over Africa. Using IPCC AR5 (Intergovernmental Panel on Climate Change; Fifth Assessment Report) estimates of anthropogenic emissions for 2030 over Africa and Asia, model calculations show larger changes in ozone over Africa due to growth in Asian emissions compared to African emissions

  5. Emission sources contributing to tropospheric ozone over equatorial Africa during the summer monsoon

    Directory of Open Access Journals (Sweden)

    I. Bouarar

    2011-05-01

    Full Text Available A global chemistry-climate model LMDz_INCA is used to investigate the contribution of African and Asian emissions to tropospheric ozone over central and West Africa during the summer monsoon. The model results show that ozone in this region is most sensitive to lightning NOx and to central African biomass burning emissions. However, other emission categories also contribute significantly to regional ozone. The maximum ozone changes due to lightning NOx occur in the upper troposphere between 400 hPa and 200 hPa over West Africa and downwind over the Atlantic Ocean. Biomass burning emissions mainly influence ozone in the lower and middle troposphere over central Africa, and downwind due to westward transport. Biogenic emissions of volatile organic compounds, which can be uplifted from the lower troposphere into higher altitudes by the deep convection that occurs over West Africa during the monsoon season, dominate the ozone changes in the upper troposphere and lower stratosphere region. Convective uplift of soil NOx emissions over the Sahel region also makes a significant contribution to ozone in the upper troposphere. Concerning African anthropogenic emissions, they make a lower contribution to ozone compared to the other emission categories. The model results indicate that most ozone changes due to African emissions occur downwind, especially over the Atlantic Ocean, far from the emission regions. The influence of Asian emissions should also be taken into account in studies of the ozone budget over Africa since they make a considerable contribution to ozone concentrations above 150 hPa. Using IPCC AR5 (Intergovernmental Panel on Climate Change; Fifth Assessment Report estimates of anthropogenic emissions for 2030 over Africa and Asia, the model calculations suggest largest changes in ozone due to the growth of emissions over Asia than over Africa over the next 20 years.

  6. Evaluating a Priori Ozone Profile Information Used in TEMPO (Tropospheric Emissions: Monitoring of Pollution) Tropospheric Ozone Retrievals

    Science.gov (United States)

    Johnson, Matthew Stephen

    2017-01-01

    A primary objective for TOLNet is the evaluation and validation of space-based tropospheric O3 retrievals from future systems such as the Tropospheric Emissions: Monitoring of Pollution (TEMPO) satellite. This study is designed to evaluate the tropopause-based O3 climatology (TB-Clim) dataset which will be used as the a priori profile information in TEMPO O3 retrievals. This study also evaluates model simulated O3 profiles, which could potentially serve as a priori O3 profile information in TEMPO retrievals, from near-real-time (NRT) data assimilation model products (NASA Global Modeling and Assimilation Office (GMAO) Goddard Earth Observing System (GEOS-5) Forward Processing (FP) and Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA2)) and full chemical transport model (CTM), GEOS-Chem, simulations. The TB-Clim dataset and model products are evaluated with surface (0-2 km) and tropospheric (0-10 km) TOLNet observations to demonstrate the accuracy of the suggested a priori dataset and information which could potentially be used in TEMPO O3 algorithms. This study also presents the impact of individual a priori profile sources on the accuracy of theoretical TEMPO O3 retrievals in the troposphere and at the surface. Preliminary results indicate that while the TB-Clim climatological dataset can replicate seasonally-averaged tropospheric O3 profiles observed by TOLNet, model-simulated profiles from a full CTM (GEOS-Chem is used as a proxy for CTM O3 predictions) resulted in more accurate tropospheric and surface-level O3 retrievals from TEMPO when compared to hourly (diurnal cycle evaluation) and daily-averaged (daily variability evaluation) TOLNet observations. Furthermore, it was determined that when large daily-averaged surface O3 mixing ratios are observed (65 ppb), which are important for air quality purposes, TEMPO retrieval values at the surface display higher correlations and less bias when applying CTM a priori profile information

  7. Migraine aura

    DEFF Research Database (Denmark)

    Charles, Andrew; Hansen, Jakob Møller

    2015-01-01

    PURPOSE OF REVIEW: The migraine aura is a dramatic spontaneous change in brain activity resulting in a variety of transient neurological symptoms. The purpose of this review is to address recent advances in the understanding of aura and its role in migraine. RECENT FINDINGS: The formal...... classification of migraine aura is becoming both broader and more detailed. Traditionally viewed as a primary event that triggers a migraine attack, studies regarding the timing of aura relative to other symptoms of migraine indicate that it may not in fact play a primary role in initiating an attack. Careful...... recording and analysis of visual aura symptoms provides new insight into the initiation and propagation of the underlying brain phenomenon, and the different regions of visual cortex that produce different visual perceptions. Migraine with aura may have different responses to acute and preventive therapies...

  8. SHADOZ in the Aura Era

    Science.gov (United States)

    Witte, J. C.; Thompson, A. M.; Oltmans, S. J.; Schoeberl, M. R.; Bhartia, P. K.; Froidevaux, L.; Schmidlin, F.; Calpini, B.; Shiotani, M.; Fujiwara, M.; Posny, F.; Vomel, H.; Chow, K. K.; Coetzee, G. R.; Kelder, H.

    2007-01-01

    We present comparisons of observed tropical and sub-tropical ozone from the Southern Hemisphere Additional Ozonesondes (SHADOZ) project with satellite measurements using Aura's Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) instruments. Satellite products of total and derived tropospheric column ozone from OMI and profiles of ozone in the UT/LS region from MLS are used.

  9. Monitoring of the Canadian Oil Sands from the Aura Satellite

    Science.gov (United States)

    McLinden, C. A.; Shephard, M. W.; Fioletov, V.; Cady-Pereira, K. E.; Krotkov, N. A.; Boersma, K. F.; Li, C.; Luo, M.; Joiner, J.; Bhartia, P. K.

    2014-12-01

    Two instruments on-board the NASA Aura satellite, the Ozone Monitoring Instrument (OMI) and Tropospheric Emission Spectrometer (TES), have been used to monitor air pollution over the Canadian oil sands region. Between them they provide a unique perspective on the distributions, evolution, and sources of several key pollutants. This presentation will detail some highlights from these Aura-based oil sands studies: (i) the evolution of OMI-measured nitrogen dioxide and sulfur dioxide enhancements over the past decade, including comparisons with other nearby sources, (ii) two years of ammonia, carbon monoxide, methanol, and formic acid observations from TES special-observation transects, and (iii) preliminary insights into emissions derived from these observations.

  10. Emission sources contributing to tropospheric ozone over Equatorial Africa during the summer monsoon

    Directory of Open Access Journals (Sweden)

    I. Bouarar

    2011-12-01

    Full Text Available A global chemistry-climate model LMDz_INCA is used to investigate the contribution of African and Asian emissions to tropospheric ozone over Central and West Africa during the summer monsoon. The model results show that ozone in this region is most sensitive to lightning NOx and to Central African biomass burning emissions. However, other emission categories also contribute significantly to regional ozone. The maximum ozone changes due to lightning NOx occur in the upper troposphere between 400 hPa and 200 hPa over West Africa and downwind over the Atlantic Ocean. Biomass burning emissions mainly influence ozone in the lower and middle troposphere over Central Africa, and downwind due to westward transport. Biogenic emissions of volatile organic compounds, which can be uplifted from the lower troposphere to higher altitudes by the deep convection that occurs over West Africa during the monsoon season, lead to maximum ozone changes in the lower stratosphere region. Soil NOx emissions over the Sahel region make a significant contribution to ozone in the lower troposphere. In addition, convective uplift of these emissions and subsequent ozone production are also an important source of ozone in the upper troposphere over West Africa. Concerning African anthropogenic emissions, they only make a small contribution to ozone compared to the other emission categories. The model results indicate that most ozone changes due to African emissions occur downwind, especially over the Atlantic Ocean, far from the emission regions. The import of Asian emissions also makes a considerable contribution to ozone concentrations above 150 hPa and has to be taken into account in studies of the ozone budget over Africa. Using IPCC AR5 (Intergovernmental Panel on Climate Change; Fifth Assessment Report estimates of anthropogenic emissions for 2030 over Africa and Asia, model calculations show larger changes in ozone over Africa due to

  11. Photochemistry of the African troposphere: Influence of biomass-burning emissions

    Science.gov (United States)

    Marufu, L.; Dentener, F.; Lelieveld, J.; Andreae, M. O.; Helas, G.

    2000-06-01

    The relative importance of biomass-burning (pyrogenic) emissions from savannas, deforestation, agricultural waste burning, and biofuel consumption to tropospheric ozone abundance over Africa has been estimated for the year 1993, on the basis of global model calculations. We also calculated the importance of this emission source to tropospheric ozone in other regions of the world and compared it to different sources on the African regional and global scales. The estimated annual average total tropospheric ozone abundance over Africa for the reference year is 26 Tg. Pyrogenic, industrial, biogenic, and lightning emissions account for 16, 19, 12, and 27%, respectively, while stratospheric ozone input accounts for 26%. In the planetary boundary layer over Africa, the contribution by biomass burning is ˜24%. A large fraction of the African biomass-burning-related ozone is transported away from the continent. On a global scale, biomass burning contributes ˜9% to tropospheric ozone. Our model calculations suggest that Africa is the single most important region for biomass-burning-related tropospheric ozone, accounting for ˜35% of the global annual pyrogenic ozone enhancement of 29 Tg in 1993.

  12. About AURA

    National Research Council Canada - National Science Library

    Consejo Editor

    2016-01-01

    On 22 October 2015 the Uruguayan Association of Academic Journals (AURA) was established. The opening ceremony was held in the Sala Maestro Julio Castro of the National Library, with the presence of 60 founding members. (...)

  13. Present and future impact of aircraft, road traffic and shipping emissions on global tropospheric ozone

    Directory of Open Access Journals (Sweden)

    B. Koffi

    2010-06-01

    Full Text Available In this study, the LMDz-INCA climate-chemistry model and up-to-date global emission inventories are used to investigate the "present" (2000 and future (2050 impacts of transport emissions (road traffic, shipping and aircraft on global tropospheric ozone. For the first time, both impacts of emissions and climate changes on transport-induced ozone are investigated. The 2000 transport emissions are shown to mainly affect ozone in the Northern Hemisphere, with a maximum increase of the tropospheric column of up to 5 DU, from the South-Eastern US to Central Europe. The impact is dominated by road traffic in the middle and upper troposphere, north of 40° S, and by shipping in the northern lower troposphere, over oceanic regions. A strong reduction of road emissions and amoderate (B1 scenario to high (A1B scenario increase of the ship and aircraft emissions are expected by the year 2050. As a consequence, LMDz-INCA simulations predict a drastic decrease in the impact of road emissions, whereas aviation would become the major transport perturbation on tropospheric ozone, even in the case of avery optimistic aircraft mitigation scenario. The A1B emission scenario leads to an increase of the impact of transport on zonal mean ozone concentrations in 2050 by up to +30% and +50%, in the Northern and Southern Hemispheres, respectively. Despite asimilar total amount of global NOx emissions by the various transport sectors compared to 2000, the overall impact on the tropospheric ozone column is increased everywhere in 2050, due to a sectoral shift in the emissions of the respective transport modes. On the opposite, the B1 mitigation scenario leads to asignificant reduction (by roughly 50% of the ozone perturbation throughout the troposphere compared to 2000.

    Considering climate change, and according to scenario A1B, a decrease of the O3 tropospheric burden is simulated by 2050 due to climate change (−1.2%, whereas an increase

  14. Global NOx emission estimates derived from an assimilation of OMI tropospheric NO2 columns

    Directory of Open Access Journals (Sweden)

    K. Sudo

    2012-03-01

    Full Text Available A data assimilation system has been developed to estimate global nitrogen oxides (NOx emissions using OMI tropospheric NO2 columns (DOMINO product and a global chemical transport model (CTM, the Chemical Atmospheric GCM for Study of Atmospheric Environment and Radiative Forcing (CHASER. The data assimilation system, based on an ensemble Kalman filter approach, was applied to optimize daily NOx emissions with a horizontal resolution of 2.8° during the years 2005 and 2006. The background error covariance estimated from the ensemble CTM forecasts explicitly represents non-direct relationships between the emissions and tropospheric columns caused by atmospheric transport and chemical processes. In comparison to the a priori emissions based on bottom-up inventories, the optimized emissions were higher over eastern China, the eastern United States, southern Africa, and central-western Europe, suggesting that the anthropogenic emissions are mostly underestimated in the inventories. In addition, the seasonality of the estimated emissions differed from that of the a priori emission over several biomass burning regions, with a large increase over Southeast Asia in April and over South America in October. The data assimilation results were validated against independent data: SCIAMACHY tropospheric NO2 columns and vertical NO2 profiles obtained from aircraft and lidar measurements. The emission correction greatly improved the agreement between the simulated and observed NO2 fields; this implies that the data assimilation system efficiently derives NOx emissions from concentration observations. We also demonstrated that biases in the satellite retrieval and model settings used in the data assimilation largely affect the magnitude of estimated emissions. These dependences should be carefully considered for better understanding NOx sources from top-down approaches.

  15. Impact of road traffic emissions on tropospheric ozone in Europe for present day and future scenarios

    Science.gov (United States)

    Mertens, Mariano; Kerkweg, Astrid; Grewe, Volker; Jöckel, Patrick

    2016-04-01

    Road traffic is an important anthropogenic source of NOx, CO and non-methane hydrocarbons (NMHCs) which act as precursors for the formation of tropospheric ozone. The formation of ozone is highly non-linear. This means that the contribution of the road traffic sector cannot directly be derived from the amount of emitted species, because they are also determined by local emissions of other anthropogenic and natural sources. In addition, long range transport of precursors and ozone can play an important role in determining the local ozone budget. For a complete assessment of the impact of road traffic emissions it is therefore important to resolve both, local emissions and long range transport. This can be achieved by the use of the newly developed MECO(n) model system, which on-line couples the global chemistry-climate-model EMAC with the regional chemistry-climate-model COSMO-CLM/MESSy. Both models use the same chemical speciation. This allows a highly consistent model chain from the global to the local scale. To quantify the contribution of the road traffic emissions to tropospheric ozone we use an accounting system of the relevant reaction pathways of the different species from different sources (called tagging method). This tagging scheme is implemented consistently on all scales, allowing a direct comparison of the contributions. With this model configuration we investigate the impact of road traffic emissions to the tropospheric ozone budget in Europe. For the year 2008 we compare different emission scenarios and investigate the influence of both model and emission resolution. In addition, results of a mitigation scenario for the year 2030 are presented. They indicate that the contribution of the road traffic sector can be reduced by local reductions of emissions during summer. During winter the importance of long range transport increases. This can lead to increased contributions of the road traffic sector (e.g. by increased emissions in the US) even if local

  16. Synergistic use of OMI NO2 tropospheric columns and LOTOS-EUROS to evaluate the NOx emission trends across Europe

    NARCIS (Netherlands)

    Curier, R.L.; Kranenburg, R.; Segers, A.J.S.; Timmermans, R.M.A.; Schaap, M.

    2014-01-01

    In this study trends in the tropospheric NO2 concentrations during 2005-2010 across Europe were derived from the synergistic use of OMI NO2 tropospheric columns and the chemistry transport model LOTOS-EUROS and were compared to reported NOx emissions. The chemistry transport model captures a large

  17. Impacts of Boreal wildfire emissions on Arctic tropospheric ozone: a multi-model analysis

    Science.gov (United States)

    Arnold, Steve; Emmons, Louisa; Monks, Sarah; Law, Kathy; Tilmes, Simone; Turquety, Solene; Thomas, Jennie; Bouarar, Idir; Raut, Jean-Christophe; Flemming, Johannes; Huijnen, Vincent; Mao, Jingqiu; Duncan, Bryan; Steenrod, Steve; Strode, Sarah; Yoshida, Yasuko

    2013-04-01

    Observations suggest that the Arctic has warmed rapidly in the past few decades compared with observed global-mean temperature increases. Model calculations suggest that changes in short-lived pollutants such as ozone and aerosol may have contributed significantly to this warming. Arctic tropospheric budgets of short-lived pollutants are impacted by long-range transport of gases and aerosols from Europe, Asia and N. America, but also by Boreal wildfires in summer. Our understanding of how Boreal fires impact Arctic budgets of climate-relevant atmospheric constituents is limited, and is reliant on sparse observations and models of tropospheric chemistry. In particular, the role of Boreal fires in the Arctic tropospheric ozone budget is poorly constrained, and has been the subject of some controversy, with different studies suggesting both minor and major roles for fires as a source of Arctic ozone. A better understanding of Boreal fire influence on Arctic ozone and aerosol is essential for improving the reliability of our projections of future Arctic and Northern Hemisphere climate change, especially in light of proposed climate-fire feedbacks which may enhance the intensity and extent of high latitude wildfire under a warming climate. Here we use results from the POLARCAT Model Intercomparison Project (POLMIP) and observations collected in the Arctic troposphere as part of International Polar Year in 2008, to evaluate simulated Arctic tropospheric ozone and how it is influenced by Boreal fire emissions in a series of state-of-the-art global atmospheric chemical transport models. By following large plumes exported from Siberian and North American Boreal fire regions in both the models and observations, we show that different models produce a wide range of influence on Arctic tropospheric ozone from fires, despite using identical emissions and having broadly consistent transport patterns. We demonstrate that the different models display highly varied NOy partitioning

  18. Impacts of Global Emissions of CO, NOx, and CH4 on China Tropospheric Hydroxyl Free Radicals

    Institute of Scientific and Technical Information of China (English)

    SU Mingfeng; LIN Yunping; FAN Xinqiang; PENG Li; ZHAO Chunsheng

    2012-01-01

    Using the global chemistry and transport model MOZART,the simulated distributions of tropospheric hydroxyl free radicals (OH) over China and its sensitivities to global emissions of carbon monoxide (CO),nitrogen oxide (NOx),and methane (CH4) were investigated in this study.Due to various distributions of OH sources and sinks,the concentrations of tropospheric OH in east China are much greater than in west China.The contribution of NO + perhydroxyl radical (HO2) reaction to OH production in east China is more pronounced than that in west China,and because of the higher reaction activity of non-methane volatile organic compounds (NMVOCs),the contributions to OH loss by NMVOCs exceed those of CO and take the dominant position in summer.The results of the sensitivity runs show a significant increase of tropospheric OH in east China from 1990 to 2000,and the trend continues.The positive effect of double emissions of NOx on OH is partly offset by the contrary effect of increased CO and CH4 emissions:the double emissions of NOx will cause an increase of OH of 18.1%-30.1%,while the increases of CO and CH4 will cause a decrease of OH of 12.2%-20.8% and 0.3%-3.0%,respectively.In turn,the lifetimes of CH4,CO,and NOx will increase by 0.3%-3.1% with regard to double emissions of CH4,13.9%-26.3% to double emissions of CO and decrease by 15.3%-23.2% to double emissions of NOx.

  19. Tropospheric Emission Spectrometer (TES) Satellite Validations of Ammonia, Methanol, Formic Acid, and Carbon Monoxide over the Canadian Oil Sands

    Data.gov (United States)

    U.S. Environmental Protection Agency — The URLs link to the data archive of the Troposphere Emission Spectrometer (TES) retrievals. These include the transects included in the Canadian Tar Sands study. A...

  20. The impact of global aviation NOx emissions on tropospheric composition changes from 2005 to 2011

    Science.gov (United States)

    Wasiuk, D. K.; Khan, M. A. H.; Shallcross, D. E.; Lowenberg, M. H.

    2016-09-01

    The impact of aviation NOx emissions from 2005 to 2011 on the chemical composition of the atmosphere has been investigated on the basis of integrations of the 3-D global chemical and transport model, STOCHEM-CRI with the novel CRIv2-R5 chemistry scheme. A base case simulation without aircraft NOx emissions and integrations with NOx emissions from aircraft are inter-compared. The sensitivity of the global atmosphere to varying the quantity and the geographical distribution of the global annual aviation NOx emissions is assessed by performing, for the first time, a series of integrations based on changing the total mass and distribution of aircraft NOx emissions derived from air traffic movements recorded between 2005 and 2011. The emissions of NOx from the global fleet based on actual records of air traffic movements between 2005 and 2011 increased the global tropospheric annual mean burden of O3 by 1.0 Tg and decreased the global tropospheric annual mean burden of CH4 by 2.5 Tg. The net NOy and O3 production increases by 0.5% and 1%, respectively between 2005 and 2011 in total. At cruise altitude, the absolute increase in the modelled O3 mixing ratios is found to be up to 0.7 ppb between 2005 and 2011 at 25°N-50°N.

  1. The influence of the vertical distribution of emissions on tropospheric chemistry

    Directory of Open Access Journals (Sweden)

    A. Pozzer

    2009-07-01

    Full Text Available The atmospheric chemistry general circulation model EMAC (ECHAM5/MESSy atmospheric chemistry is used to investigate the effect of height dependent emissions on tropospheric chemistry. In a sensitivity simulation, anthropogenic and biomass burning emissions are released in the lowest model layer. The resulting tracer distributions are compared to those of a former simulation applying height dependent emissions. Although the differences between the two simulations in the free troposphere are small (less than 5%, large differences are present in polluted regions at the surface, in particular for NOx (more than 100% and non-methane hydrocarbons (up to 30%, whereas for OH the differences at the same locations are somewhat lower (15%. Global ozone formation is virtually unaffected by the choice of the vertical distribution of emissions. Nevertheless, local ozone changes can be up to 30%. Model results of both simulations are further compared to observations from field campaigns and to data from measurement stations. The two simulations show no significant differences when compared to aircraft observations. In contrast, for measurements from surface stations, the simulation with emissions in the lowest model layer gives a 20% lower correlation to the observations compared to the simulation with height dependent emissions.

  2. Net radiative forcing due to changes in regional emissions of tropospheric ozone precursors

    Science.gov (United States)

    Naik, Vaishali; Mauzerall, Denise; Horowitz, Larry; Schwarzkopf, M. Daniel; Ramaswamy, V.; Oppenheimer, Michael

    2005-12-01

    The global distribution of tropospheric ozone (O3) depends on the emission of precursors, chemistry, and transport. For small perturbations to emissions, the global radiative forcing resulting from changes in O3 can be expressed as a sum of forcings from emission changes in different regions. Tropospheric O3 is considered in present climate policies only through the inclusion of indirect effect of CH4 on radiative forcing through its impact on O3 concentrations. The short-lived O3 precursors (NOx, CO, and NMHCs) are not directly included in the Kyoto Protocol or any similar climate mitigation agreement. In this study, we quantify the global radiative forcing resulting from a marginal reduction (10%) in anthropogenic emissions of NOx alone from nine geographic regions and a combined marginal reduction in NOx, CO, and NMHCs emissions from three regions. We simulate, using the global chemistry transport model MOZART-2, the change in the distribution of global O3 resulting from these emission reductions. In addition to the short-term reduction in O3, these emission reductions also increase CH4 concentrations (by decreasing OH); this increase in CH4 in turn counteracts part of the initial reduction in O3 concentrations. We calculate the global radiative forcing resulting from the regional emission reductions, accounting for changes in both O3 and CH4. Our results show that changes in O3 production and resulting distribution depend strongly on the geographical location of the reduction in precursor emissions. We find that the global O3 distribution and radiative forcing are most sensitive to changes in precursor emissions from tropical regions and least sensitive to changes from midlatitude and high-latitude regions. Changes in CH4 and O3 concentrations resulting from NOx emission reductions alone produce offsetting changes in radiative forcing, leaving a small positive residual forcing (warming) for all regions. In contrast, for combined reductions of anthropogenic

  3. Pollution over Megacity Regions from the Tropospheric Emission Spectrometer (TES)

    Science.gov (United States)

    Cady-Pereira, K. E.; Payne, V.; Hegarty, J. D.; Luo, M.; Bowman, K. W.; Millet, D. B.

    2015-12-01

    The world's megacities, defined as urban areas with over 10 million people, are growing rapidly in population and increasing in number, as the migration from rural to urban areas continues. This rapid growth brings economic opportunities but also exacts costs, such as traffic congestion, inadequate sanitation and poor air quality. Monitoring air quality has become a priority for many regional governments, as they seek to understand the sources and distribution of the species contributing to the local pollution. Hyperspectral infrared instruments orbiting the Earth can measure many of these species simultaneously, and since they measure averages over their footprints, they are less sensitive to proximity to strong point sources than in situ measurements, and thus provide a more regional perspective. The JPL TES team has selected a number of megacities as Special Observation targets. These observations, or transects, are sets of 20 closely spaced (12 km apart) TES observations carried out every sixteen days. We will present the TES ozone (O3), peroxyacetyl nitrate (PAN), ammonia (NH3), formic acid (HCOOH) and methanol (CH3OH) data collected over Mexico City, Lagos (Nigeria) and Los Angeles from 2013 through 2015, and illustrate how the seasonality in the TES measurements is related to local emissions, biomass burning and regional circulation patterns, and we will reinforce our arguments with MODIS AOD and TES CO data. One of the transects over Mexico City in October demonstrates very nicely the synergy obtained from simultaneous measurements of multiple trace species. We will also discuss the spatial variability along the transects and how it is related to topography and land use.

  4. Migraine with Aura

    Science.gov (United States)

    Migraine with aura Overview By Mayo Clinic Staff Migraine with aura (also called classic migraine) is a headache that strikes after or along with sensory disturbances called aura. These disturbances can include flashes of light, blind ...

  5. The influence of the vertical distribution of emissions on tropospheric chemistry

    Directory of Open Access Journals (Sweden)

    J. Van Aardenne

    2009-12-01

    Full Text Available The atmospheric chemistry general circulation model EMAC (ECHAM5/MESSy atmospheric chemistry is used to investigate the effect of height dependent emissions on tropospheric chemistry. In a sensitivity simulation, anthropogenic and biomass burning emissions are released in the lowest model layer. The resulting tracer distributions are compared to those of a former simulation applying height dependent emissions. Although the differences between the two simulations in the free troposphere are small (less than 5%, large differences are present in polluted regions at the surface, in particular for NOx (more than 100%, CO (up to 30% and non-methane hydrocarbons (up to 30%, whereas for OH the differences at the same locations are somewhat lower (15%. Global ozone formation is virtually unaffected by the choice of the vertical distribution of emissions. Nevertheless, local ozone changes can be up to 30%. Model results of both simulations are further compared to observations from field campaigns and to data from measurement stations.

  6. Tropospheric ozone changes, radiative forcing and attribution to emissions in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP

    Directory of Open Access Journals (Sweden)

    D. S. Stevenson

    2013-03-01

    Full Text Available Ozone (O3 from 17 atmospheric chemistry models taking part in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP has been used to calculate tropospheric ozone radiative forcings (RFs. All models applied a common set of anthropogenic emissions, which are better constrained for the present-day than the past. Future anthropogenic emissions follow the four Representative Concentration Pathway (RCP scenarios, which define a relatively narrow range of possible air pollution emissions. We calculate a value for the pre-industrial (1750 to present-day (2010 tropospheric ozone RF of 410 mW m−2. The model range of pre-industrial to present-day changes in O3 produces a spread (±1 standard deviation in RFs of ±17%. Three different radiation schemes were used – we find differences in RFs between schemes (for the same ozone fields of ±10%. Applying two different tropopause definitions gives differences in RFs of ±3%. Given additional (unquantified uncertainties associated with emissions, climate-chemistry interactions and land-use change, we estimate an overall uncertainty of ±30% for the tropospheric ozone RF. Experiments carried out by a subset of six models attribute tropospheric ozone RF to increased emissions of methane (44±12%, nitrogen oxides (31 ± 9%, carbon monoxide (15 ± 3% and non-methane volatile organic compounds (9 ± 2%; earlier studies attributed more of the tropospheric ozone RF to methane and less to nitrogen oxides. Normalising RFs to changes in tropospheric column ozone, we find a global mean normalised RF of 42 mW m−2 DU−1, a value similar to previous work. Using normalised RFs and future tropospheric column ozone projections we calculate future tropospheric ozone RFs (mW m−2; relative to 1750 for the four future scenarios (RCP2.6, RCP4.5, RCP6.0 and RCP8.5 of 350, 420, 370 and 460 (in 2030, and 200, 300, 280 and 600 (in 2100. Models show some coherent responses of ozone to climate change

  7. Tropospheric Ozone Changes, Radiative Forcing and Attribution to Emissions in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)

    Science.gov (United States)

    Stevenson, D.S.; Young, P.J.; Naik, V.; Lamarque, J.-F.; Shindell, D. T.; Voulgarakis, A.; Skeie, R. B.; Dalsoren, S. B.; Myhre, G.; Berntsen, T. K.; hide

    2013-01-01

    Ozone (O3) from 17 atmospheric chemistry models taking part in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) has been used to calculate tropospheric ozone radiative forcings (RFs). All models applied a common set of anthropogenic emissions, which are better constrained for the present-day than the past. Future anthropogenic emissions follow the four Representative Concentration Pathway (RCP) scenarios, which define a relatively narrow range of possible air pollution emissions. We calculate a value for the pre-industrial (1750) to present-day (2010) tropospheric ozone RF of 410 mW m-2. The model range of pre-industrial to present-day changes in O3 produces a spread (+/-1 standard deviation) in RFs of +/-17%. Three different radiation schemes were used - we find differences in RFs between schemes (for the same ozone fields) of +/-10 percent. Applying two different tropopause definitions gives differences in RFs of +/-3 percent. Given additional (unquantified) uncertainties associated with emissions, climate-chemistry interactions and land-use change, we estimate an overall uncertainty of +/-30 percent for the tropospheric ozone RF. Experiments carried out by a subset of six models attribute tropospheric ozone RF to increased emissions of methane (44+/-12 percent), nitrogen oxides (31 +/- 9 percent), carbon monoxide (15 +/- 3 percent) and non-methane volatile organic compounds (9 +/- 2 percent); earlier studies attributed more of the tropospheric ozone RF to methane and less to nitrogen oxides. Normalising RFs to changes in tropospheric column ozone, we find a global mean normalised RF of 42 mW m(-2) DU(-1), a value similar to previous work. Using normalised RFs and future tropospheric column ozone projections we calculate future tropospheric ozone RFs (mW m(-2); relative to 1750) for the four future scenarios (RCP2.6, RCP4.5, RCP6.0 and RCP8.5) of 350, 420, 370 and 460 (in 2030), and 200, 300, 280 and 600 (in 2100). Models show some

  8. Comparison between the first Odin-SMR, Aura MLS and CloudSat retrievals of cloud ice mass in the upper tropical troposphere

    Science.gov (United States)

    Eriksson, P.; Ekström, M.; Rydberg, B.; Wu, D. L.; Austin, R. T.; Murtagh, D. P.

    2007-08-01

    Emerging microwave satellite techniques are expected to provide improved global measurements of cloud ice mass. CloudSat, Aura MLS and Odin-SMR fall into this category and first cloud ice retrievals from these instruments are compared. The comparison is made for partial ice water columns above 12 km, following the SMR retrieval product. None of the instruments shows significant false cloud detections and a consistent view of the geographical distribution of cloud ice is obtained, but differences on the absolute levels exist. CloudSat gives the lowest values, with an overall mean of 2.12 g/m2. A comparable mean for MLS is 4.30 g/m2. This relatively high mean can be an indication of overestimation of the vertical altitude of cloud ice by the MLS retrievals. The vertical response of SMR has also some uncertainty, but this does not affect the comparison between MLS and CloudSat. SMR observations are sensitive to cloud inhomogeneities inside the footprint and some compensation is required. Results in good agreement with CloudSat, both in regard of the mean and probability density functions, are obtained for a weak compensation, while a simple characterisation of the effect indicates the need for stronger compensation. The SMR mean was found to be 1.89/2.62/4.10 g/m2 for no/selected/strongest compensation, respectively. Assumptions about the particle size distribution are a consideration for all three instruments, and constitute the dominating retrieval uncertainty for CloudSat. The comparison indicates a retrieval accuracy of about 40% (3.1±1.2 g/m2). This number is already very small compared to uncertainties of cloud ice parametrisation in atmospheric models, but can be decreased further through a better understanding of main retrieval error sources.

  9. Influence of future climate and cropland expansion on isoprene emissions and tropospheric ozone

    Directory of Open Access Journals (Sweden)

    O. J. Squire

    2013-07-01

    Full Text Available Over the 21st century, changes in CO2 levels, climate and land use are expected to alter the global distribution of vegetation, leading to changes in trace gas emissions from plants, including, importantly, the emissions of isoprene. This, combined with changes in anthropogenic emissions, has the potential to impact tropospheric ozone levels, which above a certain level are harmful to animals and vegetation. In this study we use a biogenic emissions model following the empirical parameterisation of the MEGAN model, with vegetation distributions calculated by the Sheffield Dynamic Global Vegetation Model (SDGVM to calculate potential future (2095 changes in isoprene emissions caused by changes in climate, land use, and the inhibition of isoprene emissions by CO2. From the present day (2000 value of 467 Tg C yr-1, we find that the combined impact of these factors causes a net decrease in isoprene emissions of 259Tg C yr-1 (55% with individual contributions of +78 Tg C yr-1 (climate change, −190 Tg C yr-1 (land use and −147 Tg C yr-1 (CO2 inhibition. Using these isoprene emissions and changes in anthropogenic emissions, a series of integrations is conducted with the UM-UKCA chemistry-climate model with the aim of examining changes in ozone over the 21st century. Globally all combined future changes cause a decrease in the tropospheric ozone burden of 27 Tg (7% from 379 Tg in the present day. At the surface, decreases in ozone of 6–10 ppb are calculated over the oceans and developed northern hemispheric regions due to reduced NOx transport by PAN and reductions in NOx emissions in these areas respectively. Increases of 4–6 ppb are calculated in the continental Tropics due to cropland expansion in these regions, increased CO2 inhibition of isoprene emissions, and higher temperatures due to climate change. These effects outweigh the decreases in tropical ozone caused by increased tropical isoprene emissions with climate change. Our land use

  10. Influence of future climate and cropland expansion on isoprene emissions and tropospheric ozone

    Directory of Open Access Journals (Sweden)

    O. J. Squire

    2014-01-01

    Full Text Available Over the 21st century, changes in CO2 levels, climate and land use are expected to alter the global distribution of vegetation, leading to changes in trace gas emissions from plants, including, importantly, the emissions of isoprene. This, combined with changes in anthropogenic emissions, has the potential to impact tropospheric ozone levels, which above a certain level are harmful to animals and vegetation. In this study we use a biogenic emissions model following the empirical parameterisation of the MEGAN model, with vegetation distributions calculated by the Sheffield Dynamic Global Vegetation Model (SDGVM to explore a range of potential future (2095 changes in isoprene emissions caused by changes in climate (including natural land use changes, land use, and the inhibition of isoprene emissions by CO2. From the present-day (2000 value of 467 Tg C yr−1, we find that the combined impact of these factors could cause a net decrease in isoprene emissions of 259 Tg C yr−1 (55% with individual contributions of +78 Tg C yr−1 (climate change, −190 Tg C yr−1 (land use and −147 Tg C yr−1 (CO2 inhibition. Using these isoprene emissions and changes in anthropogenic emissions, a series of integrations is conducted with the UM-UKCA chemistry-climate model with the aim of examining changes in ozone over the 21st century. Globally, all combined future changes cause a decrease in the tropospheric ozone burden of 27 Tg (7% from 379 Tg in the present-day. At the surface, decreases in ozone of 6–10 ppb are calculated over the oceans and developed northern hemispheric regions, due to reduced NOx transport by PAN and reductions in NOx emissions in these areas respectively. Increases of 4–6 ppb are calculated in the continental tropics due to cropland expansion in these regions, increased CO2 inhibition of isoprene emissions, and higher temperatures due to climate change. These effects outweigh the decreases in tropical ozone caused by increased

  11. Observations of Volcanic SO2 and HCl from Aura MLS

    Science.gov (United States)

    Read, W. G.; Froidevaux, L.; Santee, M. L.; Livesey, N. J.

    2009-12-01

    The Microwave Limb Sounder (MLS) on board the Aura satellite has been taking composition measurements of the Earth's upper troposphere, stratosphere and mesosphere for the past 5 years. During this time period, MLS has observed volcanic emissions from Manam, Anatahan, Soufriere Hills, Okmok, Kasatochi, Redoubt,and Sarychev eruptions. The eruptions from these volcanoes injected SO2 and HCl into the lower stratosphere. MLS makes vertically resolved measurements of these gases and therefore can determine the injection height of these volcanoes. We will provide a survey of the eruptions MLS has observed to date and compare results to SO2 columns seen by the Ozone Monitoring Instrument (OMI), also on the Aura satellite. Aura MLS however, can only make measurements along its orbit track twice daily which limits its usefulness for hazards detection or determining the amount of injected SO2. The utility of these measurements for hazard detection will be greatly enhanced in the next generation MLS instrument envisioned for the third tier decadal survey Global Atmospheric Composition Mission (GACM). The future mission will provide 50 km^2 near global coverage with 4--6 observations per day.

  12. Status of the first NASA EV-I Project, Tropospheric Emissions: Monitoring of Pollution (TEMPO)

    Science.gov (United States)

    Chance, K.; Liu, X.; Suleiman, R. M.; Flittner, D. E.; Al-Saadi, J. A.; Janz, S. J.

    2013-12-01

    TEMPO is the first NASA Earth Venture Instrument. It will measure atmospheric pollution for greater North America from space using ultraviolet and visible spectroscopy. TEMPO measures from Mexico City to the Canadian tar sands, and from the Atlantic to the Pacific, hourly and at high spatial resolution (2 km N/S × 4.5 km E/W at the center of its field of regard). The status of TEMPO including progress in instrument definition and implementation of the ground system will be presented. TEMPO provides a minimally-redundant measurement suite that includes all key elements of tropospheric air pollution chemistry. Measurements are from geostationary (GEO) orbit, to capture the inherent high variability in the diurnal cycle of emissions and chemistry. The small spatial footprint resolves pollution sources at sub-urban scale. Together, this temporal and spatial resolution improves emission inventories, monitors population exposure, and enables effective emission-control strategies. TEMPO will be delivered in 2017 for integration onto a NASA-selected GEO host spacecraft for launch as early as 2018. It will provide the spectra required to retrieve O3, NO2, SO2, H2CO, C2H2O2, H2O, aerosols, cloud parameters, and UVB radiation. TEMPO thus measures the major elements, directly or by proxy, in the tropospheric O3 chemistry cycle. Multi-spectral observations provide sensitivity to O3 in the lowermost troposphere, substantially reducing uncertainty in air quality predictions. TEMPO quantifies and tracks the evolution of aerosol loading. It provides near-real-time air quality products that will be made widely, publicly available. Additional gases not central to air quality, including BrO, OClO, and IO will also be measured. TEMPO and its Asian (GEMS) and European (Sentinel-4) constellation partners make the first tropospheric trace gas measurements from GEO, building on the heritage of six spectrometers flown in low-earth-orbit (LEO). These LEO instruments measure the needed

  13. Global Health Benefits from Reductions in Background Tropospheric Ozone due to Methane Emission Controls

    Science.gov (United States)

    West, J. J.; Mauzerall, D. L.; Fiore, A. M.; Horowitz, L. W.

    2005-05-01

    Increases in background ozone throughout the troposphere are partially attributed to rising anthropogenic methane concentrations, which are projected to continue to increase in the future. Because methane is long-lived and affects background ozone, controls on methane emissions would reduce surface ozone concentrations fairly uniformly around the globe. Epidemiological research indicates that exposure to ozone increases incidence of respiratory ailments and premature mortality. In addition, exposure to ozone reduces agricultural yields and damages natural ecosystems. We use the MOZART-2 global atmospheric chemistry and transport model to estimate the effects on global surface ozone of perturbations in methane emissions. We consider a baseline scenario for 2000 and the 2030 A2 scenario (emissions from the IPCC AR-4 2030 atmospheric chemistry experiments), and examine the impact on ozone of decreasing anthropogenic methane emissions relative to this baseline by 20%. Using the simulated spatially-distributed decreases in surface ozone concentrations resulting from these reductions in methane emissions, we estimate the global benefits to human health in the methane emission reduction scenario. We focus on human mortality, and consider the sensitivity of our estimates to different assumptions of health effect thresholds at low ozone concentrations.

  14. Methane emissions from terrestrial plants over China and their effects on methane concentrations in lower troposphere

    Institute of Scientific and Technical Information of China (English)

    XIE Min; LI Shu; JIANG Fei; WANG TiJian

    2009-01-01

    Methane (CH4) is the most important greenhouse gas and reactive trace gas in the atmosphere. Re-cently, it has been reported that terrestrial plants can emit CH4 under aerobic conditions, which may call for reevaluation of the inventory of CH4 emissions in China. In this paper, those emissions over China and their effects on CH4 concentrations in lower troposphere were investigated. Firstly, based on the work of Keppler et al., the aerobic plant CH4 emission model (PLANTCH4) for China was established.And by using the database of normalized difference vegetation index (NDVI) derived from NOAA/AVHRR, the distribution of net primary productivity (NPP) over China was simulated, and thereby, for the first time, the amount and distribution of the newly identified source in China were estimated.Secondly, with the aid of the three-dimensional atmospheric chemistry model system (MM5-CALGRiD),the effects of the emissions were studied. The results show that the annual aerobic plant CH4 emis-sions over China amount to 11.83 Tg, i.e. nearly 24% of Chinese total CH4 emissions. And the major fraction (about 43%) comes from forests. When those emissions are considered in modeling, computed countrywide mean surface concentration of CH4 is 29.9% higher than without them, with a maximum increase of 69.61 ug- m-3 in the south of Yunnan Province. In conclusion, to study CH4 emissions from terrestrial plants over China may have important implications for correctly estimating the contribution of China to global CH4 budget, and may call for a reconsideration of the role of CH4 in global and re-gional environment and climate change.

  15. Summertime upper tropospheric nitrous oxide over the Mediterranean as a footprint of Asian emissions

    Science.gov (United States)

    Kangah, Yannick; Ricaud, Philippe; Attié, Jean-Luc; Saitoh, Naoko; Hauglustaine, Didier A.; Wang, Rong; El Amraoui, Laaziz; Zbinden, Régina; Delon, Claire

    2017-04-01

    The aim of this paper is to study the transport of nitrous oxide (N2O) from the Asian surface to the eastern Mediterranean Basin (MB). We used measurements from the spectrometer Thermal and Near infrared Sensor for carbon Observation Fourier transform spectrometer on board the Greenhouse gases Observing SATellite (GOSAT) over the period of 2010-2013. We also used the outputs from the chemical transport model LMDz-OR-INCA over the same period. By comparing GOSAT upper tropospheric retrievals to aircraft measurements from the High-performance Instrumented Airborne Platform for Environmental Research Pole-to-Pole Observations, we calculated a GOSAT High-performance Instrumented Airborne Platform for Environmental Research standard deviation (SD error) of 2.0 ppbv for a single pixel and a mean bias of approximately -1.3 ppbv (approximately -0.4%). This SD error is reduced to 0.1 ppbv when we average the pixels regionally and monthly over the MB. The use of nitrogen fertilizer coupled with high soil humidity during the summer Asian monsoon produces high N2O emissions, which are transported from Asian surfaces to the eastern MB. This summertime enrichment over the eastern MB produces a maximum in the difference between the eastern and the western MB upper tropospheric N2O (east-west difference) in July in both the measurements and the model. N2O over the eastern MB can therefore be considered as a footprint of Asian summertime emissions. However, the peak-to-peak amplitude of the east-west difference observed by GOSAT ( 1.4 ± 0.3 ppbv) is larger than that calculated by LMDz-OR-INCA ( 0.8 ppbv). This is due to an underestimation of N2O emissions in the model and to a relatively coarse spatial resolution of the model that tends to underestimate the N2O accumulation into the Asian monsoon anticyclone.

  16. MeSMarT - Measurements of Shipping Emissions in the Marine Troposphere

    Science.gov (United States)

    Kattner, Lisa; Mathieu-Üffing, Barbara; Chirkov, Maksym; Burrows, John; Matthias, Volker; Richter, Andreas; Schmolke, Stefan; Theobald, Norbert; Weigelt-Krenz, Sieglinde; Wittrock, Folkard

    2013-04-01

    A new project called MeSMarT (Measurements of shipping emissions in the marine troposphere) to estimate the influence of ship emissions on the chemistry of the atmospheric boundary layer over the North Sea has been established in cooperation with the German Bundesamt für Seeschifffahrt und Hydrographie (Federal Maritime and Hydrographic Agency). Over the last years discussions about ship emissions have increased and grown in importance due to the increase of commercial shipping as well as studies about their dangerous health effects. While industrial and traffic air pollution from ashore is decreasing because of technological improvements and stronger political regulations the impact of ship emissions becomes more relevant, especially in coastal areas and harbor cities. The establishment of a Sulfur Emission Controlled Area (SECA) for the North Sea and the Baltic Sea has been a first step to control and reduce ship emissions by consecutively regulating the sulfur content of fuels. The project MeSMarT aims to monitor background concentration as well as elevated signals of gases and particles related to ship emissions with various physical and chemical methods to cover a wide range of relevant pollutants and their spatial and seasonal distribution. SO2, NO2, NO, CO2 and O3 are measured with in situ techniques, SO2 and NO2 as well by remote sensing applying the MAXDOAS-technique. The data will also be compared with satellite measurements and passive sampling in order to find a method to observe the long-term effect of regulations like SECA. High volume filter samples will be taken and analyzed especially for sulfate, nitrate, organics and elemental composition to investigate possible sources, sinks and conversion of ship emission derived compounds. Measurements and sampling take place during ship campaigns primarily in the North Sea and will be complemented with stationary measurements located on a coastal site close to the main shipping routes through the German

  17. The influence of biogenic emissions from Africa on tropical tropospheric ozone during 2006: a global modeling study

    Directory of Open Access Journals (Sweden)

    J. E. Williams

    2009-08-01

    Full Text Available We have performed simulations using a 3-D global chemistry-transport model to investigate the influence that biogenic emissions from the African continent exert on the composition of the troposphere in the tropical region. For this purpose we have applied two recently developed biogenic emission inventories provided for use in large-scale global models (Granier et al., 2005; Lathière et al., 2006 whose seasonality and temporal distribution for biogenic emissions of isoprene, other volatile organic compounds and NO is markedly different. The use of the 12 year average values for biogenic emissions provided by Lathière et al. (2006 results in an increase in the amount of nitrogen sequestrated into longer lived reservoir compounds which contributes to the reduction in the tropospheric ozone burden in the tropics. The associated re-partitioning of nitrogen between PAN, HNO3 and organic nitrates also results in a ~5% increase in the loss of nitrogen by wet deposition. At a global scale there is a reduction in the oxidizing capacity of the model atmosphere which increases the atmospheric lifetimes of CH4 and CO by ~1.5% and ~4%, respectively. Comparisons against a range of different measurements indicate that applying the 12 year average of Lathière et al. (2006 improves the performance of TM4_AMMA for 2006 in the tropics. By the use of sensitivity studies we show that the release of NO from soils in Africa accounts for between ~2–45% of tropospheric ozone in the African troposphere, ~10% in the upper troposphere and between ~5–20% of the tropical tropospheric ozone column over the tropical Atlantic Ocean. The subsequent reduction in OH over the source regions allows enhanced transport of CO out of the region. For biogenic volatile organic C1 to C3 species released from Africa, the effects on tropical tropospheric ozone are rather limited, although this source contributes to the global burden of VOC by between ~2–4% and

  18. Aura status: a not so frequent aura.

    Science.gov (United States)

    João, Ana Alagoa; Goucha, Tomas B; Martins, Isabel P

    2014-12-01

    Migraine aura status is a variety of migraine aura with unvalidated research criteria. We conducted a systematic review of published cases and a retrospective analysis of 500 cases of migraine with aura to evaluate the applicability and clinical features of ICHD-III beta criteria, compared to a more liberal definition for its diagnosis: ≥3 aura episodes for up to three consecutive days. Many publications under this title correspond to persistent or formerly designated prolonged auras. Nine cases fulfilled ICHD-III beta status criteria. In our series, either 1.7% or 4.2% cases fulfilled ICDH-III beta or our definition, respectively. Regardless of the criteria, aura status patients were older at onset of status than those with typical aura, had a predominance of visual symptoms, normal neuroimaging and no sequelae. Status recurred in a few. Both criteria identify a similar population in terms of age, gender, main symptoms, imaging and outcome. Since patients with closely recurring auras might raise the same approach independently of the criteria, the use of more liberal criteria will allow more cases for detailed diagnosis and therapeutic analysis, eventually leading to the identification of subtypes. © International Headache Society 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  19. Vertical transport of ozone and CO during super cyclones in the Bay of Bengal as detected by Tropospheric Emission Spectrometer.

    Science.gov (United States)

    Fadnavis, S; Beig, G; Buchunde, P; Ghude, Sachin D; Krishnamurti, T N

    2011-02-01

    Vertical profiles of carbon monoxide (CO) and ozone retrieved from Tropospheric Emission Spectrometer have been analyzed during two super cyclone systems Mala and Sidr. Super cyclones Mala and Sidr traversed the Bay of Bengal (BOB) region on April 24-29, 2006 and November 12-16, 2007 respectively. The CO and ozone plume is observed as a strong enhancement of these pollutants in the upper troposphere over the BOB, indicating deep convective transport. Longitude-height cross-section of these pollutants shows vertical transport to the upper troposphere. CO mixing ratio ~90 ppb is observed near the 146-mb level during the cyclone Mala and near 316 mb during the cyclone Sidr. Ozone mixing ratio ~60-100 ppb is observed near the 316-mb level during both the cyclones. Analysis of National Centers for Environmental Prediction (NCEP) reanalysis vertical winds (omega) confirms vertical transport in the BOB.

  20. Summertime mid-to-upper tropospheric nitrous oxide over the Mediterranean as a footprint of Indian emissions

    Science.gov (United States)

    Kangah, Yannick; Ricaud, Philippe; Attié, Jean-Luc; Saitoh, Naoko; Hauglustaine, Didier; El Amraoui, Laaziz; Zbinden, Regina; Delon, Claire

    2016-04-01

    We used global scale thermal infrared measurements of mid-to-upper tropospheric nitrous oxide (N2O) from the Greenhouse gases Observing SATellite (GOSAT) and outputs from the 3D Chemical Transport Model LMDz-OR-INCA to assess the impact of the Indian subcontinent N2O emissions on the N2O field over the eastern Mediterranean Basin (MB) during summer. The use of nitrogen fertilizer coupled with high soil humidity during summer monsoon period produce high emissions of N2O in many south Asian countries and especially the Indian subcontinent. N2O is transported to the upper troposphere by updrafts associated to the monsoon and redistributed westward to the eastern Mediterranean via the Asian Monsoon Anticyclone. This summertime (June-July-August) enrichment in N2O in the eastern Mediterranean produces a maximum in the east-west difference of MB mid-to-upper tropospheric N2O anomaly representative for the period 2010-2013 with a maximum in July and a peak-to-peak amplitude of ~1.0 ± 0.3 ppbv observed by GOSAT consistently with LMDz-OR-INCA but less intense (~0.5 ppbv). This summertime enrichment of N2O over the eastern Mediterranean is consistent with the increase of the surface emissions and the convective precipitations over the Indian subcontinent during the summer monsoon period. N2O over the eastern Mediterranean can therefore be considered as a footprint of Indian summertime emissions.

  1. Tropospheric Ozone as a Short-lived Chemical Climate Forcer

    Science.gov (United States)

    Pickering, Kenneth E.

    2012-01-01

    Tropospheric ozone is the third most important greenhouse gas according to the most recent IPCC assessment. However, tropospheric ozone is highly variable in both space and time. Ozone that is located in the vicinity of the tropopause has the greatest effect on climate forcing. Nitrogen oxides (NOx) are the most important precursors for ozone In most of the troposphere. Therefore, pollution that is lofted upward in thunderstorm updrafts or NOx produced by lightning leads to efficient ozone production in the upper troposphere, where ozone is most important climatically. Global and regional model estimates of the impact of North American pollution and lightning on ozone radiative forcing will be presented. It will be shown that in the Northern Hemisphere summer, the lightning effect on ozone radiative forcing can dominate over that of pollution, and that the radiative forcing signal from North America extends well into Europe and North Africa. An algorithm for predicting lightning flash rates and estimating lightning NOx emissions is being incorporated into the NASA GEOS-5 Chemistry and Climate Model. Changes in flash rates and emissions over an ENSO cycle and in future climates will be assessed, along with the resulting changes in upper tropospheric ozone. Other research on the production of NOx per lightning flash and its distribution in the vertical based on cloud-resolving modeling and satellite observations will be presented. Distributions of NO2 and O3 over the Middle East from the OMI instrument on NASA's Aura satellite will also be shown.

  2. Infrared limb emission measurements of aerosol in the troposphere and stratosphere

    Directory of Open Access Journals (Sweden)

    S. Griessbach

    2015-04-01

    Full Text Available Altitude resolved aerosol detection in the upper troposphere and lower stratosphere (UTLS is a challenging task for remote sensing instruments. Here, we introduce a new method for detecting aerosol in the UTLS based on infrared limb emission measurements. The method applies an improved aerosol-cloud-index that indicates infrared limb spectra affected by aerosol and ice clouds. For the discrimination between aerosol and ice clouds we developed a new method based on brightness temperature difference correlations. The discrimination thresholds for the new method were derived from radiative transfer simulations (including scattering and Michelson Interferometer for Passive Atmospheric Sounding (MIPAS/Envisat measurements obtained in 2011. The method not only reliably separates aerosol from ice clouds, but also provides characteristic yet overlapping correlation patterns for volcanic ash and sulfate aerosol. We demonstrate the value of the new approach for volcanic ash and sulfate aerosol originating from the Grímsvötn (Iceland, Puyehue-Cordón Caulle (Chile and Nabro (Eritrea eruptions by comparing with Atmospheric Infrared Sounder (AIRS volcanic ash and SO2 measurements.

  3. Potential Impacts of EOS-Aura Ozone Observations in Future Reanalyses

    Science.gov (United States)

    Wargan, K.; Pawson, S.; Olsen, M. A.; Witte, J. C.; Ziemke, J. R.; Douglass, A. R.

    2013-12-01

    As a crucial component of Earth's radiative budget, ozone is included in atmospheric reanalyses. Routine satellite observations of backscattered solar radiation (SBUV and TOMS datasets) provide long-term, cross-calibrated ozone records from a series of satellites, but do not have sufficient vertical resolution to resolve the sharp ozone gradients near the tropopause. Capturing this profile structure is essential for separating the stratospheric and tropospheric ozone distributions, which is important as we search for a full assessment of long-term changes in tropospheric ozone. As an important, chemically active pollutant, tropospheric ozone is known to be changing as emissions of its precursors (e.g., oxides of nitrogen) are controlled, but global impacts of such changes are complicated by the importance of the stratosphere as a source for ozone in the troposphere, as well as the roles of the lightning-produced nitrogen monoxide sources and of sinks due to chemical reactions and surface deposition. The EOS-Aura data record provides (to date) eight years of observations of total ozone column (from the Ozone Monitoring Instrument, OMI) and profiles (from the Microwave Limb Sounder, MLS). A low-resolution (2 by 2.5 degree), eight-year long assimilation experiment has been performed as a test for upcoming GMAO reanalyses, which will have higher (half-degree) spatial resolution. The analysis focuses on two aspects of the assimilated product: the degree to which this assimilation correctly separates the lower stratospheric and tropospheric air masses, and the quality of the assimilated tropospheric ozone column. There is a very good agreement between the assimilated product and independent data from ozonesondes and the High Resolution Dynamics Limb Sounder instrument. The analysis emphasizes the consistency of the assimilated ozone with temperature and dynamics, including estimates of the strength of the stratospheric ozone source for the troposphere. While these

  4. Impacts of global emissions of CO, NO x , and CH4 on China tropospheric hydroxyl free radicals

    Science.gov (United States)

    Su, Mingfeng; Lin, Yunping; Fan, Xinqiang; Peng, Li; Zhao, Chunsheng

    2012-07-01

    Using the global chemistry and transport model MOZART, the simulated distributions of tropospheric hydroxyl free radicals (OH) over China and its sensitivities to global emissions of carbon monoxide (CO), nitrogen oxide (NO x ), and methane (CH4) were investigated in this study. Due to various distributions of OH sources and sinks, the concentrations of tropospheric OH in east China are much greater than in west China. The contribution of NO + perhydroxyl radical (HO2) reaction to OH production in east China is more pronounced than that in west China, and because of the higher reaction activity of non-methane volatile organic compounds (NMVOCs), the contributions to OH loss by NMVOCs exceed those of CO and take the dominant position in summer. The results of the sensitivity runs show a significant increase of tropospheric OH in east China from 1990 to 2000, and the trend continues. The positive effect of double emissions of NO x on OH is partly offset by the contrary effect of increased CO and CH4 emissions: the double emissions of NO x will cause an increase of OH of 18.1%-30.1%, while the increases of CO and CH4 will cause a decrease of OH of 12.2%-20.8% and 0.3%-3.0%, respectively. In turn, the lifetimes of CH4, CO, and NO x will increase by 0.3%-3.1% with regard to double emissions of CH4, 13.9%-26.3% to double emissions of CO and decrease by 15.3%-23.2% to double emissions of NO x .

  5. The Response of Lower Atmospheric Ozone to ENSO in Aura Measurements and a Chemistry-Climate Simulation

    Science.gov (United States)

    Oman, L. D.; Douglass, A. R.; Ziemke, J. R.; Rodriquez, J. M.; Waugh, D. W.; Nielsen, J. E.

    2012-01-01

    The El Nino-Southern Oscillation (ENSO) is the dominant mode of tropical variability on interannual time scales. ENSO appears to extend its influence into the chemical composition of the tropical troposphere. Recent work has revealed an ENSO-induced wave-1 anomaly in observed tropical tropospheric column ozone. This results in a dipole over the western and eastern tropical Pacific, whereby differencing the two regions produces an ozone anomaly with an extremely high correlation to the Nino 3.4 Index. We have successfully reproduced this feature using the Goddard Earth Observing System Version 5 (GEOS-5) general circulation model coupled to a comprehensive stratospheric and tropospheric chemical mechanism forced with observed sea surface temperatures over the past 25 years. An examination of the modeled ozone field reveals the vertical contributions of tropospheric ozone to the column over the western and eastern Pacific region. We will show composition sensitivity in observations from NASA s Aura satellite Microwave Limb Sounder (MLS) and the Tropospheric Emissions Spectrometer (TES) and a simulation to provide insight into the vertical structure of these ENSO-induced ozone changes. The ozone changes due to the Quasi-Biennial Oscillation (QBO) in the extra-polar upper troposphere and lower stratosphere in MLS measurements will also be discussed.

  6. Multiannual changes of CO2 emissions in China: indirect estimates derived from satellite measurements of tropospheric NO2 columns

    Directory of Open Access Journals (Sweden)

    M. Beekmann

    2013-01-01

    Full Text Available Multi-annual satellite measurements of tropospheric NO2 columns are used for evaluation of CO2 emission changes in China in the period from 1996 to 2008. Indirect annual top-down estimates of CO2 emissions are derived from the satellite NO2 columns measurements by means of a simple inverse modeling procedure involving simulations performed with the CHIMERE mesoscale chemistry transport model and the CO2 to NOx emission ratios from the Emission Database for Global Atmospheric Research version 4.2 (EDGAR v4.2 global anthropogenic emission inventory. Exponential trends in the normalized time series of annual emission are evaluated separately for the periods from 1996 to 2001 and from 2001 to 2008. The results indicate that the both periods manifest strong positive trends in the CO2 emissions, and that the trend in the second period was significantly larger than the trend in the first period. Specifically, the trends in the first and second periods are estimated to be in the range from 3.7 to 8.0 and from 9.5 to 13.0 percent per year, respectively, taking into account both statistical and probable systematic uncertainties. Comparison of our top-down estimates of the CO2 emission changes with the corresponding bottom-up estimates provided by EDGAR v4.2 and Global Carbon Project (GCP emission inventories reveals that while acceleration of the CO2 emission growth in the considered period is a common feature of the both kinds of estimates, nonlinearity in the CO2 emission changes may be strongly exaggerated in the emission inventories. Specifically, the atmospheric NO2 observations do not confirm the existence of a sharp bend in the emission inventory data time series in the period from 2000 to 2002. A significant quantitative difference is revealed between the bottom-up and top-down estimates of the CO2 emission trend in the period from 1996 to 2001 (specifically, the trend was not positive according to the emission inventories, but is strongly

  7. Climate versus emission drivers of methane lifetime against loss by tropospheric OH from 1860-2100

    Science.gov (United States)

    John, J. G.; Fiore, A. M.; Naik, V.; Horowitz, L. W.; Dunne, J. P.

    2012-12-01

    With a more-than-doubling in the atmospheric abundance of the potent greenhouse gas methane (CH4) since preindustrial times, and indications of renewed growth following a leveling off in recent years, questions arise as to future trends and resulting climate and public health impacts from continued growth without mitigation. Changes in atmospheric methane lifetime are determined by factors which regulate the abundance of OH, the primary methane removal mechanism, including changes in CH4 itself. We investigate the role of emissions of short-lived species and climate in determining the evolution of methane lifetime against loss by tropospheric OH, (τCH4_OH), in a suite of historical (1860-2005) and future Representative Concentration Pathway (RCP) simulations (2006-2100), conducted with the Geophysical Fluid Dynamics Laboratory (GFDL) fully coupled chemistry-climate model (CM3). From preindustrial to present, CM3 simulates an overall 5% increase in τCH4_OH due to a doubling of the methane burden which offsets coincident increases in nitrogen oxide (NOx emissions. Over the last two decades, however, the τCH4_OH declines steadily, coinciding with the most rapid climate warming and observed slow-down in CH4 growth rates, reflecting a possible negative feedback through the CH4 sink. Sensitivity simulations with CM3 suggest that the aerosol indirect effect (aerosol-cloud interactions) plays a significant role in cooling the CM3 climate. The projected decline in aerosols under all RCPs contributes to climate warming over the 21st century, which influences the future evolution of OH concentration and τCH4_OH. Projected changes in τCH4_OH from 2006 to 2100 range from -13% to +4%. The only projected increase occurs in the most extreme warming case (RCP8.5) due to the near-doubling of the CH4 abundance, reflecting a positive feedback on the climate system. The largest decrease occurs in the RCP4.5 scenario due to changes in short-lived climate forcing agents which

  8. Investigation of aviation emission impacts on global tropospheric chemistry and climate using a size-resolved aerosol-chemistry model

    Science.gov (United States)

    Kapadia, Zarashpe; Spracklen, Dominick; Arnold, Stephen; Borman, Duncan; Mann, Graham; Pringle, Kirsty; Monks, Sarah; Reddington, Carly; Rap, Alexandru; Scott, Catherine

    2014-05-01

    Aviation is responsible for 3% of global anthropogenic CO2 emissions, but 2-14% of anthropogenic induced climate warming due to contributions from short lived climate forcers. The global civil aviation fleet is projected to double by 2026 in relation to a 2006 baseline and so will play a substantial role in future climate change. Uncertainty in the net impact of aviation on climate is largely due to uncertainty in the impacts of aviation emissions on ozone and aerosol. To study the impact of aviation emissions we use the GLOMAP-mode global aerosol microphysics model coupled to the 3-D chemical transport model TOMCAT. GLOMAP-mode has been extended to include treatment of nitrate aerosol. We include a full suite of non-CO2 aviation emissions (including NOX, SO2, HCs, BC and OC) in the model. We combined the simulated changes in ozone and aerosol with a 3D radiative transfer model to quantify the radiative effect due to aviation non-CO2 emissions. We find that aviation emissions increase O3 concentrations by up to 5.3% in the upper troposphere (UT), broadly matching previous studies. Black carbon (BC) and organic carbon (OC) concentrations increase by 26.5% and 14.6% respectively in the UT, whereas nitrate aerosol is reduced in some regions due to co-emission of NOX and SO2 In the UT, aviation emissions increase both total aerosol number as well as the concentration of particles greater than 70 nm diameter (N70). Entrainment of these particles into the free troposphere results in aviation emissions also increasing N70 in the boundary layer, causing a cooling through the first aerosol indirect effect. We explore differences in these responses compared with those simulated when using the recommended aviation emissions from CMIP5 (5th Climate Model Intercomparison Project), which only include NOX and BC emissions. Our results suggest that aviation emissions of SO2 and HCs neglected by CMIP5 produce important effects on ozone, aerosol number, and N70. We suggest CMIP5

  9. Composition of the Asian summer monsoon anticyclone: Climatology and variability from 10 years of Aura Microwave Limb Sounder measurements

    Science.gov (United States)

    Santee, Michelle; Manney, Gloria; Livesey, Nathaniel; Neu, Jessica; Schwartz, Michael; Read, William

    2016-04-01

    Satellite measurements are invaluable for investigating the composition of the upper troposphere / lower stratosphere (UTLS) in the region of the Asian summer monsoon anticyclone, which has been sparsely sampled by other means. The Microwave Limb Sounder (MLS), launched as part of NASA's Aura mission in July 2004, makes simultaneous co-located measurements of trace gases and cloud ice water content (IWC, a proxy for deep convection) in the UTLS on a daily basis. Here we exploit the dense spatial and temporal coverage, long-term data record, and extensive measurement suite of Aura MLS to characterize the climatological composition of the ASM anticyclone and quantify its considerable spatial, seasonal, and interannual variability. We relate the observed trace gas behavior to various meteorological quantities, such as the size and strength of the ASM anticyclone, the extent and intensity of deep convection, and variations in the tropopause and the upper tropospheric jets in that region. Multiple species of both tropospheric and stratospheric origin are examined to help assess whether the observed variability arises from variations in transport processes or changes in the strength or location of surface emissions.

  10. Hiccups as a migraine aura.

    Science.gov (United States)

    Chaudhry, Priyanka; Friedman, Deborah I

    2015-08-01

    To report a case series of hiccup as a migraine aura. Hiccup is a syndrome of inappropriate muscle contraction. To our knowledge, hiccup as a migraine aura has not been reported. We describe series of patients who presented with hiccups as their migraine aura symptom. Hiccups can present as a primary aura symptom in patients with migraine. © International Headache Society 2014.

  11. Uncertainty in the Future Distribution of Tropospheric Ozone over West Africa due to Variability in Anthropogenic Emissions Estimates between 2025 and 2050

    Directory of Open Access Journals (Sweden)

    J. E. Williams

    2011-01-01

    Full Text Available Particle and trace gas emissions due to anthropogenic activity are expected to increase significantly in West Africa over the next few decades due to rising population and more energy intensive lifestyles. Here we perform 3D global chemistry-transport model calculations for 2025 and 2050 using both a “business-as-usual” (A1B and “clean economy” (B1 future anthropogenic emission scenario to focus on the changes in the distribution and uncertainties associated with tropospheric O3 due to the various projected emission scenarios. When compared to the present-day troposphere we find that there are significant increases in tropospheric O3 for the A1B emission scenario, with the largest increases being located in the lower troposphere near the source regions and into the Sahel around 15–20°N. In part this increase is due to more efficient NOx re-cycling related to increases in the background methane concentrations. Examining the uncertainty across different emission inventories reveals that there is an associated uncertainty of up to ~20% in the predicted increases at 2025 and 2050. For the upper troposphere, where increases in O3 have a more pronounced impact on radiative forcing, the uncertainty is influenced by transport of O3 rich air from Asia on the Tropical Easterly Jet.

  12. Quantifying the uncertainty in simulating global tropospheric composition due to the variability in global emission estimates of Biogenic Volatile Organic Compounds

    Directory of Open Access Journals (Sweden)

    J. E. Williams

    2012-11-01

    Full Text Available The emission of organic compounds from biogenic processes acts as an important source of trace gases in remote regions away from urban conurbations, and is likely to become more important in future decades due to the further mitigation of anthropogenic emissions that affect air quality and climate forcing. In this study we examine the contribution of biogenic volatile organic compounds (BVOCs towards global tropospheric composition using the global 3-D chemistry transport model TM5 and the recently developed modified CB05 chemical mechanism. By comparing regional BVOC emission estimates we show that biogenic processes act as dominant sources for many regions and exhibit a large variability in the annually and seasonally integrated emission fluxes. By performing sensitivity studies we find that the contribution of BVOC species containing between 1 to 3 carbon atoms has an impact on the resident mixing ratios of tropospheric O3 and CO, accounting for ~3% and ~11% of the simulated global distribution, respectively. This is approximately a third of the cumulative effect introduced by isoprene and the monoterpenes. By examining an ensemble of 3-D global chemistry-transport simulations which adopt different global BVOC emission inventories we determine the associated uncertainty introduced towards simulating the composition of the troposphere for the year 2000. By comparing the model ensemble values against a~composite of atmospheric measurements we show that the effects on tropospheric O3 are limited to the lower troposphere (with an uncertainty between −2% to 10%, whereas that for tropospheric CO extends up to the upper troposphere (with an uncertainty of between 10 to 45%. Comparing the mixing ratios for low molecular weight alkenes in TM5 against surface measurements taken in Europe implies that the cumulative emission estimates are too low, regardless of the chosen BVOC inventory. This variability in the global

  13. Satellite Monitoring Over the Canadian Oil Sands: Highlights from Aura OMI and TES

    Science.gov (United States)

    Shephard, Mark W.; McLinden, Chris; Fioletov, Vitali; Cady-Pereira, Karen E.; Krotkov, Nick A.; Boersma, Folkert; Li, Can; Luo, Ming; Bhartia, P. K.; Joiner, Joanna

    2014-01-01

    Satellite remote sensing provides a unique perspective for air quality monitoring in and around the Canadian Oil Sands as a result of its spatial and temporal coverage. Presented are Aura satellite observations of key pollutants including nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon monoxide (CO), ammonia (NH3), methanol (CH3OH), and formic acid (HCOOH) over the Canadian Oil Sands. Some of the highlights include: (i) the evolution of NO2 and SO2 from the Ozone Monitoring Instrument (OMI), including comparisons with other nearby sources, (ii) two years of ammonia, carbon monoxide, methanol, and formic acid observations from 240 km North-South Tropospheric Emission Spectrometer (TES) transects through the oils sands, and (iii) preliminary insights into emissions derived from these observations.

  14. PM2.5 and tropospheric O3 in China and an analysis of the impact of pollutant emission control

    Directory of Open Access Journals (Sweden)

    Hua Zhang

    2014-09-01

    Full Text Available This study reviewed the status of PM2.5 and tropospheric O3 observations in China (15–55°N, 72–136°E. Initially, the distribution of tropospheric O3 over the globe and China was determined based on satellite observations made during 2010–2013. The annual mean values were 29.78 DU and 33.97 DU over the globe and China, respectively. The distribution of PM2.5 and seasonal changes in concentrations in China were then simulated using an aerosol chemistry–climate coupled model system, with an annual mean value of 0.51 × 10−8 kg m−3. The contributions from five different aerosols to the simulated PM2.5 concentrations in different seasons were also determined. The relationships among the emissions of aerosols, greenhouse gases and their precursors and radiative forcings were determined with reference to the (IPCC AR5 Intergovernmental Panel on Climate Change the Fifth Assessment Report. From these relationships, the possible effects of controlling O3 precursors and (PM particulate matter on the climate were considered. The influence of the control of O3 precursors was not totally clear, and reducing emissions of short-lived greenhouse gases and black carbon was considered a secondary measure for short-term (the next 50 years climate-change mitigation. Reducing emissions of CO2 is still the best strategy for meeting the target of a global average rise in surface air temperature of less than 2 °C. Near- and short-term emission reduction strategies are important for both effective environmental protection and climate-change mitigation.

  15. Identification of tropospheric emissions sources from satellite observations: Synergistic use of HCHO, NO2, and SO2 trace gas measurements

    Science.gov (United States)

    Marbach, T.; Beirle, S.; Khokhar, F.; Platt, U.

    2005-12-01

    We present case studies for combined HCHO, NO2, and SO2 satellite observations, derived from GOME measurements. Launched on the ERS-2 satellite in April 1995, GOME has already performed continuous operations over 8 years providing global observations of the different trace gases. In this way, satellite observations provide unique opportunities for the identifications of trace gas sources. The satellite HCHO observations provide information concerning the localization of biomass burning (intense source of HCHO). The principal biomass burning areas can be observed in the Amazon basin region and in central Africa Weaker HCHO sources (south east of the United States, northern part of the Amazon basin, and over the African tropical forest), not correlated with biomass burning, could be due to biogenic isoprene emissions. The HCHO data can be compared with NO2 and SO2 results to identify more precisely the tropospheric sources (biomass burning events, human activities, additional sources like volcanic emissions). Biomass burning are important tropospheric sources for both HCHO and NO2. Nevertheless HCHO reflects more precisely the biomass burning as it appears in all biomass burning events. NO2 correlate with HCHO over Africa (grassland fires) but not over Indonesia (forest fires). In south America, an augmentation of the NO2 concentrations can be observed with the fire shift from the forest to grassland vegetation. So there seems to be a dependence between the NO2 emissions during biomass burning and the vegetation type. Other high HCHO, SO2, and NO2 emissions can be correlated with climatic events like the El Nino in 1997, which induced dry conditions in Indonesia causing many forest fires.

  16. Emission Ratios of the Tropospheric Ozone Precursors Nitrogen Dioxide and Formaldehyde from Australia’s Black Saturday Fires

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    Clare Paton-Walsh

    2011-10-01

    Full Text Available The ‘Black Saturday’ fires were a series of devastating forest fires that burned across Victoria, Australia, during February and March of 2009. In this study we have used satellite data made publically available by NASA from the Ozone Monitoring Instrument (OMI and the Atmospheric InfraRed Sounder (AIRS to track the smoke plume from the Black Saturday firestorm and explore the chemical aging of the smoke plume in the first days after emission. We also determined emission ratios for formaldehyde and nitrogen dioxide within smoke from fires actively burning across Victoria between 7 and 17 February 2009. The mean emission ratios with respect to carbon monoxide derived for these two tropospheric ozone precursors are (0.016 ± 0.004 mol.mol−1 for formaldehyde and (0.005 ± 0.002 mol.mol−1 for nitrogen dioxide. The mean emission ratio for formaldehyde with respect to CO is in broad agreement with values previously quoted in the literature for temperate forest fires. However, to our knowledge there are no previous measurements of emission ratios for nitrogen dioxide from Australian temperate forest fires.

  17. The Response of Tropospheric Ozone to ENSO in Observations and a Chemistry-Climate Simulation

    Science.gov (United States)

    Oman, L. D.; Douglass, A. R.; Ziemke, J. R.; Waugh, D. W.; Rodriguez, J. M.; Nielsen, J. E.

    2012-01-01

    The El Nino-Southern Oscillation (ENSO) is the dominant mode of tropical variability on interannual time scales. ENSO appears to extend its influence into the chemical composition of the tropical troposphere. Recent results have revealed an ENSO induced wave-l anomaly in observed tropical tropospheric column ozone. This results in a dipole over the western and eastern tropical Pacific, whereby differencing the two regions produces an ozone anomaly with an extremely high correlation to the Nino 3.4 Index. We have successfully reproduced this result using the Goddard Earth Observing System Version 5 (GEOS-5) general circulation model coupled to a comprehensive stratospheric and tropospheric chemical mechanism forced with observed sea surface temperatures over the past 25 years. An examination of the modeled ozone field reveals the vertical contributions of tropospheric ozone to the column over the western and eastern Pacific region. We will show targeted comparisons with observations from NASA's Aura satellite Microwave Limb Sounder (MLS), and the Tropospheric Emissions Spectrometer (TES) to provide insight into the vertical structure of ozone changes. The tropospheric ozone response to ENSO could be a useful chemistry-climate model evaluation tool and should be considered in future modeling assessments.

  18. Tropospheric ozone changes, radiative forcing and attribution to emissions in the Atmospheric Chemistry and Climate Model Inter-comparison Project (ACCMIP

    Directory of Open Access Journals (Sweden)

    D. S. Stevenson

    2012-10-01

    Full Text Available Ozone (O3 from 17 atmospheric chemistry models taking part in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP has been used to calculate tropospheric ozone radiative forcings (RFs. We calculate a~value for the pre-industrial (1750 to present-day (2010 tropospheric ozone RF of 0.40 W m−2. The model range of pre-industrial to present-day changes in O3 produces a spread (±1 standard deviation in RFs of ±17%. Three different radiation schemes were used – we find differences in RFs between schemes (for the same ozone fields of ±10%. Applying two different tropopause definitions gives differences in RFs of ±3%. Given additional (unquantified uncertainties associated with emissions, climate-chemistry interactions and land-use change, we estimate an overall uncertainty of ±30% for the tropospheric ozone RF. Experiments carried out by a subset of six models attribute tropospheric ozone RF to increased emissions of methane (47%, nitrogen oxides (29%, carbon monoxide (15% and non-methane volatile organic compounds (9%; earlier studies attributed more of the tropospheric ozone RF to methane and less to nitrogen oxides. Normalising RFs to changes in tropospheric column ozone, we find a global mean normalised RF of 0.042 W m−2 DU−1, a value similar to previous work. Using normalised RFs and future tropospheric column ozone projections we calculate future tropospheric ozone RFs (W m−2; relative to 1850 – add 0.04 W m−2 to make relative to 1750 for the Representative Concentration Pathways in 2030 (2100 of: RCP2.6: 0.31 (0.16; RCP4.5: 0.38 (0.26; RCP6.0: 0.33 (0.24; and RCP8.5: 0.42 (0.56. Models show some coherent responses of ozone to climate change: decreases in the tropical lower troposphere, associated with increases in water vapour; and increases in the sub-tropical to mid-latitude upper troposphere, associated with increases in

  19. The zonal structure of tropical O3 and CO as observed by the Tropospheric Emission Spectrometer in November 2004 – Part 2: Impact of surface emissions on O3 and its precursors

    Directory of Open Access Journals (Sweden)

    G. Osterman

    2009-06-01

    Full Text Available The impact of surface emissions on the zonal structure of tropical tropospheric ozone and carbon monoxide is investigated for November 2004 using satellite observations, in-situ measurements, and chemical transport models in conjunction with inverse-estimated surface emissions.Vertical ozone profiles from the Tropospheric Emission Spectrometer (TES and ozone sonde measurements from the Southern Hemisphere Additional Ozonesondes (SHADOZ network show elevated concentrations of ozone over Indonesia and Australia (60–70 ppb in the lower troposphere against the backdrop of the well-known zonal "wave-one" pattern with ozone concentrations of (70–80 ppb centered over the Atlantic . Observational evidence from TES CO vertical profiles and Ozone Monitoring Instrument (OMI NO2 columns point to regional surface emissions as an important contributor to the elevated ozone over Indonesia. This contribution is investigated with the GEOS-Chem chemistry and transport model using surface emission estimates derived from an optimal inverse model, which was constrained by TES and Measurements Of Pollution In The Troposphere (MOPITT CO profiles (Jones et al., 2009. These a posteriori estimates, which were over a factor of 2 greater than climatological emissions, reduced differences between GEOS-Chem and TES ozone observations by 30–40% over Indonesia. The response of the free tropospheric chemical state to the changes in these emissions is investigated for ozone, CO, NOx, and PAN. Model simulations indicate that ozone over Indonesian/Australian is sensitive to regional changes in surface emissions of NOx but relatively insensitive to lightning NOx. Over sub-equatorial Africa and South America, free tropospheric NOx was reduced in response to increased surface emissions potentially muting ozone production.

  20. The influence of boreal biomass burning emissions on the distribution of tropospheric ozone over North America and the North Atlantic during 2010

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    M. Parrington

    2012-02-01

    Full Text Available We have analysed the sensitivity of the tropospheric ozone distribution over North America and the North Atlantic to boreal biomass burning emissions during the summer of 2010 using the GEOS-Chem 3-D global tropospheric chemical transport model and observations from in situ and satellite instruments. We show that the model ozone distribution is consistent with observations from the Pico Mountain Observatory in the Azores, ozonesondes across Canada, and the Tropospheric Emission Spectrometer (TES and Infrared Atmospheric Sounding Instrument (IASI satellite instruments. Mean biases between the model and observed ozone mixing ratio in the free troposphere were less than 10 ppbv. We used the adjoint of GEOS-Chem to show the model ozone distribution in the free troposphere over Maritime Canada is largely sensitive to NOx emissions from biomass burning sources in Central Canada, lightning sources in the central US, and anthropogenic sources in the eastern US and south-eastern Canada. We also used the adjoint of GEOS-Chem to evaluate the Fire Locating And Monitoring of Burning Emissions (FLAMBE inventory through assimilation of CO observations from the Measurements Of Pollution In The Troposphere (MOPITT satellite instrument. The CO inversion showed that, on average, the FLAMBE emissions needed to be reduced to 89% of their original values, with scaling factors ranging from 12% to 102%, to fit the MOPITT observations in the boreal regions. Applying the CO scaling factors to all species emitted from boreal biomass burning sources led to a decrease of the model tropospheric distributions of CO, PAN, and NOx by as much as −20 ppbv, −50 pptv, and −20 pptv respectively. The modification of the biomass burning emission estimates reduced the model ozone distribution by approximately −3 ppbv (−8% and on average improved the agreement of the model ozone distribution compared to the observations throughout the free troposphere

  1. Influence of the Vegetation Type on CH2O and NO2 Tropospheric Emissions during Biomass Burning: Synergistic use of Satellite Observations

    Science.gov (United States)

    Marbach, T.; Beirle, S.; Hollwedel, J.; Khokhar, F.; Platt, U.; Wagner, T.

    Satellite observations are a helpful tool for the identification of the sources for tropospheric emissions by providing global observations of the different trace gases. We present case studies for the combined observations of CH2O and NO2 derived from observations made by the Global Ozone Monitoring Experiment (GOME). Launched on the ERS-2 satellite in April, 1995, GOME has already performed continuous operations over 8 years. The satellite CH2O observations provide information concerning the localization of biomass burning (intense source of CH2O). The principal biomass burning areas can be observed in the amazonian forest and in central Africa. Other high CH2O emissions can be correlated with climatic events like El Nino in 1997, which induced dry conditions in Indonesia causing many forest fires. Tree isoprene emissions contribute also for high CH2O concentrations especially in southwest United States. Biomass burning are also an important tropospheric source for NO2 emissions and can be compared with the CH2O emissions to discriminate the influence of the vegetation type on the tropospheric emissions of both trace gases during biomass burning: the change in the vegetation type can be followed with the change in the intensity of CH2O and NO2 emissions.

  2. Las declinaciones del aura

    OpenAIRE

    Bettoni, Cecilia

    2016-01-01

    Habitualmente, asociamos el concepto benjaminiano de aura a una cualidad de la obra de arte que desfallece con el creciente desarrollo de las técnicas mecánicas de reproducción. Sin embargo, el mismo Benjamin señala que este desfallecimiento es un proceso sintomático, cuyo significado desborda el dominio puramente artístico. En este contexto, el presente artículo indaga este desborde a partir de la elasticidad que la noción de aura alcanza en la obra de Walter Benjamin, con el objeto de demos...

  3. Quantification of the impact of aircraft traffic emissions on tropospheric ozone over Paris area

    Science.gov (United States)

    Pison, Isabelle; Menut, Laurent

    Accurate estimations of the emissions of primary pollutants are crucial for the modeling of photo-oxidants' concentrations. For a majority of chemistry-transport models (CTMs), these emissions are taken into account near the surface only. They are expressed as surface fluxes and represent surface activities such as traffic, industries or biogenic processes. However, in the vicinity of large cities, commercial aircraft emissions represent a nonnegligible source, located both at the surface and at altitude, including landing and take-off of aircraft within the boundary layer. This is the case of Paris where one national airport (Le Bourget) and two international airports (Roissy-Charles-de-Gaulle and Orly) are located less than 30 km away from the city center. This study presents the first-model analysis of the impact of aircraft emissions on photo-oxidant concentrations over the Paris area. Using a three-dimensional aircraft emission inventory, we compare ozone surface concentrations obtained with and without these emissions by running the CTM CHIMERE during the second Intensive Observation Period of the ESQUIF project. The simulated differences enable us to estimate the impact of aircraft traffic emissions on ozone surface concentrations in and around the city. The results showed that the maximum impact, which consists in a fast ozone titration by NO near the airports within the surface layer, occurs during the night. In remote areas and at altitude, adding new emissions enhanced photo-chemistry during the afternoon. In order to estimate the impact of the uncertainty of our inventory, aircraft emitted masses of volatile organic compounds (VOCs) and NO x are perturbed. The results showed that NO x air traffic emissions have a more important impact than VOC emissions, particularly during the night and near the sources. Nevertheless, these variations of air traffic emissions do not change previous conclusions.

  4. EOS Aura Mission Status

    Science.gov (United States)

    Guit, William J.

    2015-01-01

    This PowerPoint presentation will discuss EOS Aura mission and spacecraft subsystem summary, recent and planned activities, inclination adjust maneuvers, propellant usage lifetime estimate. Eric Moyer, ESMO Deputy Project Manager-Technical (code 428) has reviewed and approved the slides on April 30, 2015.

  5. Tropospheric Emissions: Monitoring of Pollution (TEMPO) - Status and Potential Science Studies

    Science.gov (United States)

    Chance, Kelly

    2016-05-01

    TEMPO is the first NASA Earth Venture Instrument, to launch between 2019 and 2021. It measures atmospheric pollution from Mexico City and Cuba to the Canadian oil sands, and from the Atlantic to the Pacific, hourly at high spatial resolution, ~ 10 km2. It measures the key elements of air pollution chemistry. Geostationary (GEO) measurements capture the variability in the diurnal cycle of emissions and chemistry at sub-urban scale to improve emission inventories, monitor population exposure, and enable emission-control strategies. TEMPO measures the UV/visible spectra to retrieve O3, NO2, SO2, H2 CO, C2 H2 O2, H2 O, aerosols, cloud parameters, and UVB radiation. It tracks aerosol loading. It provides near-real-time air quality products. TEMPO is the North American component of the global geostationary constellation for pollution monitoring, with the European Sentinel-4 and the Korean GEMS. TEMPO studies may include: Solar-induced fluorescence from chlorophyll over land and in the ocean to study tropical dynamics, primary productivity, carbon uptake, to detect red tides, and to study phytoplankton; Measurements of stratospheric intrusions that cause air quality exceedances; Measurements at peaks in vehicle travel to capture the variability in emissions from mobile sources; Measurements of thunderstorm activity, including outflow regions to better quantify lightning NOx and O3 production; Cropland measurements follow the temporal evolution of emissions after fertilizer application and from rain-induced emissions from semi-arid soils; Measurements investigate the chemical processing of primary fire emissions and the secondary formation of VOCs and ozone; Measurements examine ocean halogen emissions and their impact on the oxidizing capacity of coastal environments; Spectra of nighttime lights are markers for human activity, energy conservation, and compliance with outdoor lighting standards intended to reduce light pollution.

  6. Improving Air Quality Forecasts with AURA Observations

    Science.gov (United States)

    Newchurch, M. J.; Biazer, A.; Khan, M.; Koshak, W. J.; Nair, U.; Fuller, K.; Wang, L.; Parker, Y.; Williams, R.; Liu, X.

    2008-01-01

    Past studies have identified model initial and boundary conditions as sources of reducible errors in air-quality simulations. In particular, improving the initial condition improves the accuracy of short-term forecasts as it allows for the impact of local emissions to be realized by the model and improving boundary conditions improves long range transport through the model domain, especially in recirculating anticyclones. During the August 2006 period, we use AURA/OMI ozone measurements along with MODIS and CALIPSO aerosol observations to improve the initial and boundary conditions of ozone and Particulate Matter. Assessment of the model by comparison of the control run and satellite assimilation run to the IONS06 network of ozonesonde observations, which comprise the densest ozone sounding campaign ever conducted in North America, to AURA/TES ozone profile measurements, and to the EPA ground network of ozone and PM measurements will show significant improvement in the CMAQ calculations that use AURA initial and boundary conditions. Further analyses of lightning occurrences from ground and satellite observations and AURA/OMI NO2 column abundances will identify the lightning NOx signal evident in OMI measurements and suggest pathways for incorporating the lightning and NO2 data into the CMAQ simulations.

  7. Improving Air Quality Forecasts with AURA Observations

    Science.gov (United States)

    Newchurch, M. J.; Biazer, A.; Khan, M.; Koshak, W. J.; Nair, U.; Fuller, K.; Wang, L.; Parker, Y.; Williams, R.; Liu, X.

    2008-01-01

    Past studies have identified model initial and boundary conditions as sources of reducible errors in air-quality simulations. In particular, improving the initial condition improves the accuracy of short-term forecasts as it allows for the impact of local emissions to be realized by the model and improving boundary conditions improves long range transport through the model domain, especially in recirculating anticyclones. During the August 2006 period, we use AURA/OMI ozone measurements along with MODIS and CALIPSO aerosol observations to improve the initial and boundary conditions of ozone and Particulate Matter. Assessment of the model by comparison of the control run and satellite assimilation run to the IONS06 network of ozonesonde observations, which comprise the densest ozone sounding campaign ever conducted in North America, to AURA/TES ozone profile measurements, and to the EPA ground network of ozone and PM measurements will show significant improvement in the CMAQ calculations that use AURA initial and boundary conditions. Further analyses of lightning occurrences from ground and satellite observations and AURA/OMI NO2 column abundances will identify the lightning NOx signal evident in OMI measurements and suggest pathways for incorporating the lightning and NO2 data into the CMAQ simulations.

  8. Tropospheric ozone production related to West African city emissions during the 2006 wet season AMMA campaign

    Directory of Open Access Journals (Sweden)

    G. Ancellet

    2010-11-01

    Full Text Available During the African Monsoon Multidisciplinary Analyses (AMMA airborne measurements of ozone, CO and nitrogen oxides by the French and German falcon aircraft took place near three cities in West Africa (Cotonou, Niamey and Ouagadougou. Significant ozone production (O3 increase of 40–50 ppbv took place during two specific events: one near Cotonou on the coast of the Guinea Gulf, and the other near Niamey in the Sahel region. In both cases a high level of NOx (>3 ppbv is related to the ozone production. The ozone production is mainly driven by the Lagos-Cotonou anthropogenic emissions in Cotonou. In Niamey the combined effect of advection of VOC emissions from the forest and stagnation over the city area and the poorly vegetated soils recently wetted by convected systems is needed to achieve a similar level of ozone precursors. In Ouagadougou no ozone plume is found because of the absence of a pause in the convective activity and of the larger vegetated area around the city which prevented ozone plume formation during the wet season.

    To discuss the ozone increase near Cotonou two different approaches have been implemented: a FLEXPART simulation to quantify the probability of transport from the SH compared to air mass stagnation over the emission area and a simulation of the BOLAM mesoscale model with two different tracers for the anthropogenic emission (RETRO inventory for 2000 and the biomass burning. The BOLAM model shows a good agreement with the meteorological observations of the aircraft and allows to identify the key influence of the anthropogenic emissions in the first 3 km while the biomass burning plume remains above this altitude.

    The day to day variability of the ozone and CO in Niamey and Ouagadougou is discussed using FLEXPART simulations of the air mass stagnation in the 12° N–14° N latitude band and northward advection of air masses from the vegetated areas influenced by the biogenic

  9. Spatial variability in tropospheric peroxyacetyl nitrate in the tropics from infrared satellite observations in 2005 and 2006

    Science.gov (United States)

    Payne, Vivienne H.; Fischer, Emily V.; Worden, John R.; Jiang, Zhe; Zhu, Liye; Kurosu, Thomas P.; Kulawik, Susan S.

    2017-05-01

    Peroxyacetyl nitrate (PAN) plays a fundamental role in the global ozone budget and is the primary reservoir of tropospheric reactive nitrogen over much of the globe. However, large uncertainties exist in how surface emissions, transport and lightning affect the global distribution, particularly in the tropics. We present new satellite observations of free-tropospheric PAN in the tropics from the Aura Tropospheric Emission Spectrometer. This dataset allows us to test expected spatiotemporal distributions that have been predicted by models but previously not well observed. We compare here with the GEOS-Chem model with updates specifically for PAN. We observe an austral springtime maximum over the tropical Atlantic, a feature that model predictions attribute primarily to lightning. Over northern central Africa in December, observations show strong interannual variability, despite low variation in fire emissions, that we attribute to the combined effects of changes in biogenic emissions and lightning. We observe small enhancements in free-tropospheric PAN corresponding to the extreme burning event over Indonesia associated with the 2006 El Niño.

  10. Sensitivity of tropospheric ozone to chemical kinetic uncertainties in air masses influenced by anthropogenic and biomass burning emissions

    Science.gov (United States)

    Ridley, D. A.; Cain, M.; Methven, J.; Arnold, S. R.

    2017-07-01

    We use a Lagrangian chemical transport model with a Monte Carlo approach to determine impacts of kinetic rate uncertainties on simulated concentrations of ozone, NOy and OH in a high-altitude biomass burning plume and a low-level industrial pollution plume undergoing long-range transport. Uncertainties in kinetic rate constants yield 10-12 ppbv (5th to 95th percentile) uncertainty in the ozone concentration, dominated by reactions that cycle NO and NO2, control NOx conversion to NOy reservoir species, and key reactions contributing to O3 loss (O(1D) + H2O, HO2 + O3). Our results imply that better understanding of the peroxyacetylnitrate (PAN) thermal decomposition constant is key to predicting large-scale O3 production from fire emissions and uncertainty in the reaction of NO + O3 at low temperatures is particularly important for both the anthropogenic and biomass burning plumes. The highlighted reactions serve as a useful template for targeting new laboratory experiments aimed at reducing uncertainties in our understanding of tropospheric O3 photochemistry.

  11. High resolution modeling of the upper troposphere and lower stratosphere region over the Arctic - GEM-AC simulations for the future climate with and without aviation emissions.

    Science.gov (United States)

    Porebska, Magdalena; Struzewska, Joanna; Kaminski, Jacek W.

    2016-04-01

    Upper troposphere and lower stratosphere (UTLS) region is a layer around the tropopause. Perturbation of the chemical composition in the UTLS region can impact physical and dynamical processes that can lead to changes in cloudiness, precipitation, radiative forcing, stratosphere-troposphere exchange and zonal flow. The objective of this study is to investigate the potential impacts of aviation emissions on the upper troposphere and lower stratosphere. In order to assess the impact of the aviation emissions we will focus on changes in atmospheric dynamic due to changes in chemical composition in the UTLS over the Arctic. Specifically, we will assess perturbations in the distribution of the wind, temperature and pressure fields in the UTLS region. Our study will be based on simulations using a high resolution chemical weather model for four scenarios of current (2006) and future (2050) climate: with and without aircraft emissions. The tool that we use is the GEM-AC (Global Environmental Multiscale with Atmospheric Chemistry) chemical weather model where air quality, free tropospheric and stratospheric chemistry processes are on-line and interactive in an operational weather forecast model of Environment Canada. In vertical, the model domain is defined on 70 hybrid levels with model top at 0.1 mb. The gas-phase chemistry includes detailed reactions of Ox, NOx, HOx, CO, CH4, ClOx and BrO. Also, the model can address aerosol microphysics and gas-aerosol partitioning. Aircraft emissions are from the AEDT 2006 database developed by the Federal Aviation Administration (USA) and the future climate simulations are based on RCP8.5 projection presented by the IPCC in the fifth Assessment Report AR5. Results from model simulations on a global variable grid with 0.5o x 0.5o uniform resolution over the Arctic will be presented.

  12. Cephalic Aura after Frontal Lobe Resection

    OpenAIRE

    2014-01-01

    A cephalic aura is a common sensory aura typically seen in frontal lobe epilepsy. The generation mechanism of cephalic aura is not fully understood. It is hypothesized that to generate cephalic aura more extensive cortical areas need to be excited. Here we report a patient who started to have cephalic aura after right frontal lobe resection. MEG showed interictal spike and ictal change during cephalic aura, both of which were distributed on right frontal region, and the latter involved much m...

  13. Clinical Analysis of Partial Epilepsy with Auras

    Directory of Open Access Journals (Sweden)

    Yang Liu

    2017-01-01

    Conclusions: This study suggested that auras played an important role in the diagnosis, classification, and localization of epilepsy. Epileptic aura could help differentiate partial seizure from generalized seizure.

  14. The influence of ozone precursor emissions from four world regions on tropospheric composition and radiative climate forcing

    Science.gov (United States)

    Fry, Meridith M.; Naik, Vaishali; West, J. Jason; Schwarzkopf, M. Daniel; Fiore, Arlene M.; Collins, William J.; Dentener, Frank J.; Shindell, Drew T.; Atherton, Cyndi; Bergmann, Daniel; Duncan, Bryan N.; Hess, Peter; MacKenzie, Ian A.; Marmer, Elina; Schultz, Martin G.; Szopa, Sophie; Wild, Oliver; Zeng, Guang

    2012-04-01

    Ozone (O3) precursor emissions influence regional and global climate and air quality through changes in tropospheric O3 and oxidants, which also influence methane (CH4) and sulfate aerosols (SO42-). We examine changes in the tropospheric composition of O3, CH4, SO42- and global net radiative forcing (RF) for 20% reductions in global CH4 burden and in anthropogenic O3 precursor emissions (NOx, NMVOC, and CO) from four regions (East Asia, Europe and Northern Africa, North America, and South Asia) using the Task Force on Hemispheric Transport of Air Pollution Source-Receptor global chemical transport model (CTM) simulations, assessing uncertainty (mean ± 1 standard deviation) across multiple CTMs. We evaluate steady state O3responses, including long-term feedbacks via CH4. With a radiative transfer model that includes greenhouse gases and the aerosol direct effect, we find that regional NOx reductions produce global, annually averaged positive net RFs (0.2 ± 0.6 to 1.7 ± 2 mWm-2/Tg N yr-1), with some variation among models. Negative net RFs result from reductions in global CH4 (-162.6 ± 2 mWm-2 for a change from 1760 to 1408 ppbv CH4) and regional NMVOC (-0.4 ± 0.2 to -0.7 ± 0.2 mWm-2/Tg C yr-1) and CO emissions (-0.13 ± 0.02 to -0.15 ± 0.02 mWm-2/Tg CO yr-1). Including the effect of O3 on CO2 uptake by vegetation likely makes these net RFs more negative by -1.9 to -5.2 mWm-2/Tg N yr-1, -0.2 to -0.7 mWm-2/Tg C yr-1, and -0.02 to -0.05 mWm-2/Tg CO yr-1. Net RF impacts reflect the distribution of concentration changes, where RF is affected locally by changes in SO42-, regionally to hemispherically by O3, and globally by CH4. Global annual average SO42- responses to oxidant changes range from 0.4 ± 2.6 to -1.9 ± 1.3 Gg for NOxreductions, 0.1 ± 1.2 to -0.9 ± 0.8 Gg for NMVOC reductions, and -0.09 ± 0.5 to -0.9 ± 0.8 Gg for CO reductions, suggesting additional research is needed. The 100-year global warming potentials (GWP100) are calculated for the global CH

  15. Influence of enhanced Asian NOx emissions on ozone in the upper troposphere and lower stratosphere in chemistry-climate model simulations

    Science.gov (United States)

    Roy, Chaitri; Fadnavis, Suvarna; Müller, Rolf; Ayantika, D. C.; Ploeger, Felix; Rap, Alexandru

    2017-01-01

    The Asian summer monsoon (ASM) anticyclone is the most pronounced circulation pattern in the upper troposphere and lower stratosphere (UTLS) during northern hemispheric summer. ASM convection plays an important role in efficient vertical transport from the surface to the upper-level anticyclone. In this paper we investigate the potential impact of enhanced anthropogenic nitrogen oxide (NOx) emissions on the distribution of ozone in the UTLS using the fully coupled aerosol-chemistry-climate model, ECHAM5-HAMMOZ. Ozone in the UTLS is influenced both by the convective uplift of ozone precursors and by the uplift of enhanced-NOx-induced tropospheric ozone anomalies. We performed anthropogenic NOx emission sensitivity experiments over India and China. In these simulations, covering the years 2000-2010, anthropogenic NOx emissions have been increased by 38 % over India and by 73 % over China with respect to the emission base year 2000. These emission increases are comparable to the observed linear trends of 3.8 % per year over India and 7.3 % per year over China during the period 2000 to 2010. Enhanced NOx emissions over India by 38 % and China by 73 % increase the ozone radiative forcing in the ASM anticyclone (15-40° N, 60-120° E) by 16.3 and 78.5 mW m-2 respectively. These elevated NOx emissions produce significant warming over the Tibetan Plateau and increase precipitation over India due to a strengthening of the monsoon Hadley circulation. However, increase in NOx emissions over India by 73 % (similar to the observed increase over China) results in large ozone production over the Indo-Gangetic Plain and Tibetan Plateau. The higher ozone concentrations, in turn, induce a reversed monsoon Hadley circulation and negative precipitation anomalies over India. The associated subsidence suppresses vertical transport of NOx and ozone into the ASM anticyclone.

  16. Observation of ozone enhancement in the lower troposphere over East Asia from a space-borne ultraviolet spectrometer

    Science.gov (United States)

    Hayashida, S.; Liu, X.; Ono, A.; Yang, K.; Chance, K.

    2015-09-01

    We report observations from space using ultraviolet (UV) radiance for significant enhancement of ozone in the lower troposphere over central and eastern China (CEC). The recent retrieval products of the Ozone Monitoring Instrument (OMI) onboard the Earth Observing System (EOS) Aura satellite revealed the spatial and temporal variation of ozone distributions in multiple layers in the troposphere. We compared the OMI-derived ozone over Beijing with airborne measurements by the Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC) program. The correlation between OMI and MOZAIC ozone in the lower troposphere was reasonable, which assured the reliability of OMI ozone retrievals in the lower troposphere under enhanced ozone conditions. The ozone enhancement was clearly observed over CEC, with Shandong Province as its center, and was most notable in June in any given year. Similar seasonal variations were observed throughout the 9-year OMI measurement period of 2005 to 2013. A considerable part of this ozone enhancement could be attributed to the emissions of ozone precursors from industrial activities and automobiles, and possibly from open crop residue burning (OCRB) after the winter wheat harvest. The ozone distribution presented in this study is also consistent with some model studies. The lower tropospheric ozone distribution is first shown from OMI retrieval in this study, and the results will be useful in clarifying any unknown factors that influence ozone distribution by comparison with model simulations.

  17. Model Calculations of Changes in Tropospheric Ozone Over Europe and the Role of Surface Sources and Aircraft Emissions

    Energy Technology Data Exchange (ETDEWEB)

    Hov, Oe. [Bergen Univ. (Norway)

    1996-01-01

    This conference paper deals with a study of the impact of various sources of NO{sub x} on the ozone production in the free troposphere. A comprehensive two-dimensional zonally averaged chemistry/transport model and a three-dimensional meso-scale chemical transport (MCT) model are used in the study. Using the two-dimensional model, three surches of NO{sub x} in the upper troposphere were examined covering NO{sub x} produced by lightening, NO{sub x} (and NO{sub y}) brought to the upper troposphere from the planetary boundary layer by rapid vertical transport processes, and NO{sub x} emitted from aircraft. 4 refs.

  18. Clinical Analysis of Partial Epilepsy with Auras

    Science.gov (United States)

    Liu, Yang; Guo, Xiao-Ming; Wu, Xun; Li, Ping; Wang, Wei-Wei

    2017-01-01

    Background: An aura is usually considered to be the initial clinical sign of a seizure. The types of abnormal neuron activities (i.e., localized and generalized firing) play an important role in the diagnosis of epilepsy. The goal of this study was to investigate the types of auras and its correlation with the localization and treatment of epilepsy. Methods: The 426 epileptic patients with auras from a single center were reviewed with reference to International League Against Epilepsy (ILAE, 1981) classification; the clinical manifestations and incidence of auras were analyzed in this retrospective study, as well as the results of electroencephalogram (EEG), brain magnetic resonance imaging (MRI) and the treatment methods. Results: Among the 426 epileptic patients, six different types of auras were defined, including autonomic auras, sensory auras, mental and affective auras, aura as vertigo, cognitive auras, and unspeakable feelings. Duration of auras ranged from 2 s to 7 min; the median duration of auras was 64.2 s. Abnormal EEG was observed in 297 (69.72%) patients. Moreover, abnormal brain MRI was observed in 125 (29.34%) patients. Nineteen (4.46%) epilepsy patients with auras underwent both surgeries and antiepileptic drugs (AEDs) while others were treated only with AEDs. Conclusions: This study suggested that auras played an important role in the diagnosis, classification, and localization of epilepsy. Epileptic aura could help differentiate partial seizure from generalized seizure. PMID:28139515

  19. The Influence of Ozone Precursor Emissions from Four World Regions on Tropospheric Composition and Radiative Climate Forcing

    Science.gov (United States)

    Fry, Meridith; Naik, Vaishali; West, J. Jason; Schwarzkopf, M. Daniel; Fiore, Arlene M.; Collins, William J.; Dentener, Frank J.; Shindell, Drew T.; Atherton, Cyndi; Bergmann, Daniel; Duncan, Bryan N.; Hess, Peter; MacKenzie, Ian A.; Marmer, Elina; Schultz, Martin G.; Szopa, Sophie; Wild, Oliver; Zeng, Guang

    2012-01-01

    Ozone (O3) precursor emissions influence regional and global climate and air quality through changes in tropospheric O3 and oxidants, which also influence methane (CH4) and sulfate aerosols (SO4 (sup 2-)). We examine changes in the tropospheric composition of O3, CH4, SO4 (sup 2-) and global net radiative forcing (RF) for 20% reductions in global CH4 burden and in anthropogenic O3 precursor emissions (NOx, NMVOC, and CO) from four regions (East Asia, Europe and Northern Africa, North America, and South Asia) using the Task Force on Hemispheric Transport of Air Pollution Source-Receptor global chemical transport model (CTM) simulations, assessing uncertainty (mean plus or minus 1 standard deviation) across multiple CTMs. We evaluate steady state O3 responses, including long-term feedbacks via CH4. With a radiative transfer model that includes greenhouse gases and the aerosol direct effect, we find that regional NOx reductions produce global, annually averaged positive net RFs (0.2 plus or minus 0.6 to 1.7 2 mWm(sup -2)/Tg N yr(sup -1), with some variation among models. Negative net RFs result from reductions in global CH4 (-162.6 plus or minus 2 mWm(sup -2) for a change from 1760 to 1408 ppbv CH4) and regional NMVOC (-0.4 plus or minus 0.2 to 0.7 plus or minus 0.2 mWm(sup -2)/Tg C yr(sup -1) and CO emissions (-0.13 plus or minus 0.02 to -0.15 plus or minus 0.02 mWm(sup-2)/Tg CO yr(sup-1). Including the effect of O3 on CO2 uptake by vegetation likely makes these net RFs more negative by -1.9 to- 5.2 mWm(sup -2)/Tg N yr(sup -1), -0.2 to -0.7 mWm(sup -2)/Tg C yr(sup -1), and -0.02 to -0.05 mWm(sup -2)/ Tg CO yr(sup -1). Net RF impacts reflect the distribution of concentration changes, where RF is affected locally by changes in SO4 (sup -2), regionally to hemispherically by O3, and globally by CH4. Global annual average SO4 2 responses to oxidant changes range from 0.4 plus or minus 2.6 to -1.9 plus or minus 1.3 Gg for NOx reductions, 0.1 plus or minus 1.2 to -0.9 plus

  20. OMI tropospheric NO

    NARCIS (Netherlands)

    Castellanos, P.; Boersma, K.F.; Torres, O.; Haan, De J.F.

    2015-01-01

    Biomass burning is an important and uncertain source of aerosols and NOx (NO + NO2) to the atmosphere. Satellite observations of tropospheric NO2 are essential for characterizing this emissions source, but inaccuracies in the retrieval of NO2 tropospher

  1. Trends in emissions and concentrations of air pollutants in the lower troposphere in the Baltimore/Washington airshed from 1997 to 2011

    Directory of Open Access Journals (Sweden)

    H. He

    2013-08-01

    Full Text Available Trends in the composition of the lower atmosphere (0–1500 m altitude and surface air quality over the Baltimore/Washington area and surrounding states were investigated for the period from 1997 to 2011. We examined emissions of ozone precursors from monitors and inventories as well as ambient ground-level and aircraft measurements to characterize trends in air pollution. The US EPA Continuous Emissions Monitoring System (CEMS program reported substantial decreases in emission of summertime nitrogen oxides (NOx from power plants, up to ∼80% in the mid-Atlantic States. These large reductions in emission of NOx are reflected in a sharp decrease of ground-level concentrations of NOx starting around 2003. The decreasing trend of tropospheric column CO observed by aircraft is ∼0.8 Dobson unit (DU per year, corresponding to ∼35 ppbv yr−1 in the lower troposphere (the surface to 1500 m above ground level. Satellite observations of long-term, near-surface CO show a ∼40% decrease over western Maryland between 2000 and 2011; the same magnitude is indicated by aircraft measurements above these regions upwind of the Baltimore/Washington airshed. With decreasing emissions of ozone precursors, the ground-level ozone in the Baltimore/Washington area shows a 0.6 ppbv yr−1 decrease in the past 15 yr. Since photochemical production of ozone is substantially influenced by ambient temperature, we introduce the climate penalty factor (CPF into the trend analysis of long-term aircraft measurements. After compensating for inter-annual variations in temperature, historical aircraft measurements indicate that the daily net production of tropospheric ozone over the Baltimore/Washington area decreased from ∼20 ppbv day−1 in the late 1990s to ∼7 ppbv day−1 in the early 2010s during ozone season. A decrease in the long-term column ozone is observed as ∼0.2 DU yr−1 in the lowest 1500 m, corresponding to an improvement of ∼1.3 ppbv yr−1. Our

  2. NASA 3D Models: Aura

    Data.gov (United States)

    National Aeronautics and Space Administration — Aura observes the chemical content of the atmosphere to track the state of the ozone layer and the dispersion of airborne pollution. Polygons: 6 Vertices: 4

  3. Improved description of the migraine aura by a diagnostic aura diary

    DEFF Research Database (Denmark)

    Russell, M B; Iversen, Helle Klingenberg; Olesen, J

    1994-01-01

    We present a diagnostic aura diary for prospective recordings of migraine with aura. Three questionnaires are supplemented with sheets for drawings and plottings of visual and sensory auras. Twenty patients recorded 54 attacks of migraine with aura and 2 attacks of migraine aura without headache...... of migraine. The visual and sensory auras always preceded typical migraine headache, and headache occurring before aura symptoms was always of the tension type. The migraine headache was milder than in attacks of migraine without aura and often did not have migraine characteristics. In attacks with unilateral...

  4. The impact of air pollutant and methane emission controls on tropospheric ozone and radiative forcing: CTM calculations for the period 1990–2030

    Directory of Open Access Journals (Sweden)

    F. Raes

    2004-12-01

    Full Text Available To explore the relationship between tropospheric ozone and radiative forcing with changing emissions, we compiled two sets of global scenarios for the emissions of the ozone precursors methane (CH4, carbon monoxide (CO, non-methane volatile organic compounds (NMVOC and nitrogen oxides (NOx up to the year 2030 and implemented them in two global Chemistry Transport Models. The "Current Legislation" (CLE scenario reflects the current perspectives of individual countries on future economic development and takes the anticipated effects of presently decided emission control legislation in the individual countries into account. In addition, we developed a "Maximum technically Feasible Reduction" (MFR scenario that outlines the scope for emission reductions offered by full implementation of the presently available emission control technologies, while maintaining the projected levels of anthropogenic activities. Whereas the resulting projections of methane emissions lie within the range suggested by other greenhouse gas projections, the recent pollution control legislation of many Asian countries, requiring introduction of catalytic converters for vehicles, leads to significantly lower growth in emissions of the air pollutants NOx, NMVOC and CO than was suggested by the widely used IPCC (Intergovernmental Panel on Climate Change SRES (Special Report on Emission Scenarios scenarios (Nakicenovic et al., 2000. With the TM3 and STOCHEM models we performed several long-term integrations (1990–2030 to assess global, hemispheric and regional changes in CH4, CO, hydroxyl radicals, ozone and the radiative climate forcings resulting from these two emission scenarios. Both models reproduce realistically the observed trends in background ozone, CO, and CH4 concentrations from 1990 to 2002. For the "current legislation" case, both models indicate an increase of the annual average ozone levels in the Northern hemisphere by 5 ppbv, and up to 15 ppbv over the Indian

  5. Observational Diagnoses of Extratropical Ozone STE During the Aura Era

    Science.gov (United States)

    Olsen, Mark A.; Douglass, Anne R.; Witte, Jacquie C.; Kaplan, Trevor B.

    2011-01-01

    The transport of ozone from the stratosphere to the extratropical troposphere is an important boundary condition to tropospheric chemistry. However, previous direct estimates from models and indirect estimates from observations have poorly constrained the magnitude of ozone stratosphere-troposphere exchange (STE). In this study we provide a direct diagnosis of the extratropical ozone STE using data from the Microwave Limb Sounder on Aura and output of the MERRA reanalysis over the time period from 2005 to the present. We find that the mean annual STE is about 275 Tg/yr and 205 Tg/yr in the NH and SH, respectively. The interannual variability of the magnitude is about twice as great in the NH than the SH. We find that this variability is dominated by the seasonal variability during the late winter and spring. A comparison of the ozone flux to the mass flux reveals that there is not a simple relationship between the two quantities. This presentation will also examine the magnitude and distribution of ozone in the lower stratosphere relative to the years of maximum and minimum ozone STE. Finally, we will examine any possible signature of increased ozone STE in the troposphere using sonde and tropospheric ozone residual (TOR) data, and output from the Global Modeling Initiative Chemistry Transport Model (GMI CTM).

  6. Reduced efficacy of sumatriptan in migraine with aura vs without aura

    DEFF Research Database (Denmark)

    Hansen, Jakob Møller; Goadsby, Peter J; Charles, Andrew

    2015-01-01

    treated attacks with aura (24%) (p freedom 2 hours postdose for attacks without aura was 1.33 (95% confidence interval: 1.16-1.54). The number needed to treat for 2 hours of pain freedom was 4.4 for attacks without aura and 6.2 for attacks with aura. For the clinical...... trial of DHE, the 2-hour pain-free rates did not differ between patients treating attacks without aura (29.4%) compared with those who treated attacks with aura (27.2%; p = 0.65). The relative risk for pain freedom 2 hours postdose for attacks without aura vs with aura was 1.08 (95% confidence interval...... compared with attacks without aura. In the single study of inhaled DHE, the treatment had similar efficacy for migraine attacks with and without aura. Different responses of migraine with vs without aura to acute therapies may provide insight into underlying migraine mechanisms and influence the choice...

  7. Changes in springtime tropospheric ozone observed at Mt. Happo, Japan: New insights for the roles of Asian emissions and long-range transport

    Science.gov (United States)

    Okamoto, Sachiko; Ikeda, Kohei; Tanimoto, Hiroshi

    2017-04-01

    We revisited and updated the long-term trend of tropospheric ozone at Mt. Happo, Japan, based on continuous measurements for the period from 1998 to 2016. We focused on the springtime ozone concentration and possible influences by the continental outflow from East Asia. Since 1998 the springtime ozone concentration has shown a large increase until 2007, very likely caused by the increase in the emissions of ozone precursors associated with economic growth in eastern China, as evidenced from satellite observations of nitrogen dioxides. In 2008 and 2012, two large decreases in ozone were observed, followed by a stabilization until now. The residence time of air masses passed over central eastern China, which is the most polluted region in China, showed high levels during 2004-2007, and then decreased in 2008. Meteorological variability as well as emissions of ozone precursors are important factors controlling the ozone concentration at Mt. Happo.

  8. Interpretation of Aura satellite observations of CO and aerosol index related to the December 2006 Australia fires

    Directory of Open Access Journals (Sweden)

    N. Livesey

    2009-11-01

    Full Text Available Enhanced Carbon Monoxide (CO in the upper troposphere (UT is shown by collocated Tropospheric Emission Spectrometer (TES and Microwave Limb Sounder (MLS measurements near and down-wind from the known wildfire region of SE Australia from 12–19 December 2006. Enhanced UV aerosol index (AI derived from Ozone Monitoring Instrument (OMI measurements correlate with these high CO concentrations. HYSPLIT model back trajectories trace selected air parcels to the SE Australia fire region as their initial location, where TES observes enhanced CO in the upper and lower troposphere. Simultaneously, they show a lack of vertical advection along their tracks. TES retrieved CO vertical profiles in the higher and lower southern latitudes are examined together with the averaging kernels and show that TES CO retrievals are most sensitive at approximately 300–400 hPa. The enhanced CO observed by TES at the upper (215 hPa and lower (681 hPa troposphere are, therefore, influenced by mid-tropospheric CO. GEOS-Chem model simulations with an 8-day emission inventory, as the wildfire source over Australia, are sampled to the TES/MLS observation times and locations. These simulations only show CO enhancements in the lower troposphere near and down-wind from the wildfire region of SE Australia with drastic underestimates of UT CO. Although CloudSat along-track ice-water content curtains are examined to see whether possible vertical convection events can explain the high UT CO values, sparse observations of collocated Aura CO and CloudSat along-track ice-water content measurements for the single event precludes any conclusive correlation. Vertical convection that uplift fire-induced CO (i.e. most notably referred to as pyro-cumulonimbus, pyroCb may provide an explanation for the incongruence between these simulations and the TES/MLS observations of enhanced CO in the UT. Future GEOS-Chem simulations are needed to validate this conjecture as the the PyroCb mechanism is

  9. Trends in emissions and concentrations of air pollutants in the lower troposphere in the Baltimore/Washington airshed from 1997 to 2011

    Directory of Open Access Journals (Sweden)

    H. He

    2013-02-01

    Full Text Available Trends in the composition of the lower atmosphere (0–1500 m altitude and surface air quality over the Baltimore/Washington area and surrounding states were investigated for the period from 1997 to 2011. We examined emissions, ground-level observations and long-term aircraft measurements to characterize trends in air pollution. The USEPA Continuous Emissions Monitoring System (CEMS program reported substantial decreases in point sources resulting from national and regional control measures; these decreases are definitely reflected in the ground-level observations. The decreasing trend of CO column contents is ~8.0 Dobson Unit (DU decade−1, corresponding to ~350 ppbv decade−1 in the lower troposphere. Satellite observations of long-term, near-surface CO show ~40% decrease over western Maryland between 2000 and 2011, the same magnitude as indicated by aircraft measurements over upwind regions of Baltimore/Washington aished. After compensating for inter-annual temperature variations, historical aircraft measurements suggest the daily net production of tropospheric ozone over Baltimore/Washington area decreases from ~20 ppbv in the late 1990s to ~7 ppbv in the early 2010s during the ozone season. A decrease in the long-term ozone column content is observed as ~2.0 DU decade−1 in the lowest 1500 m, corresponding to ~13 ppbv decade−1 decrease. Back trajectory cluster analysis demonstrates that emissions of air pollutants from Ohio and Pennsylvania through Maryland influence column contents of downwind ozone in the lower atmosphere. The trends of air pollutants reveal the success of regulations implemented over the last decade and the importance of region wide emission controls over the eastern United States.

  10. Cephalic aura after frontal lobe resection.

    Science.gov (United States)

    Kakisaka, Yosuke; Jehi, Lara; Alkawadri, Rafeed; Wang, Zhong I; Enatsu, Rei; Mosher, John C; Dubarry, Anne-Sophie; Alexopoulos, Andreas V; Burgess, Richard C

    2014-08-01

    A cephalic aura is a common sensory aura typically seen in frontal lobe epilepsy. The generation mechanism of cephalic aura is not fully understood. It is hypothesized that to generate a cephalic aura extensive cortical areas need to be excited. We report a patient who started to have cephalic aura after right frontal lobe resection. Magnetoencephalography (MEG) showed interictal spike and ictal change during cephalic aura, both of which were distributed in the right frontal region, and the latter involved much more widespread areas than the former on MEG sensors. The peculiar seizure onset pattern may indicate that surgical modification of the epileptic network was related to the appearance of cephalic aura. We hypothesize that generation of cephalic aura may be associated with more extensive cortical involvement of epileptic activity than that of interictal activity, in at least a subset of cases.

  11. Tropospheric Aerosols

    Science.gov (United States)

    Buseck, P. R.; Schwartz, S. E.

    2003-12-01

    It is widely believed that "On a clear day you can see forever," as proclaimed in the 1965 Broadway musical of the same name. While an admittedly beautiful thought, we all know that this concept is only figurative. Aside from Earth's curvature and Rayleigh scattering by air molecules, aerosols - colloidal suspensions of solid or liquid particles in a gas - limit our vision. Even on the clearest day, there are billions of aerosol particles per cubic meter of air.Atmospheric aerosols are commonly referred to as smoke, dust, haze, and smog, terms that are loosely reflective of their origin and composition. Aerosol particles have arisen naturally for eons from sea spray, volcanic emissions, wind entrainment of mineral dust, wildfires, and gas-to-particle conversion of hydrocarbons from plants and dimethylsulfide from the oceans. However, over the industrial period, the natural background aerosol has been greatly augmented by anthropogenic contributions, i.e., those produced by human activities. One manifestation of this impact is reduced visibility (Figure 1). Thus, perhaps more than in other realms of geochemistry, when considering the composition of the troposphere one must consider the effects of these activities. The atmosphere has become a reservoir for vast quantities of anthropogenic emissions that exert important perturbations on it and on the planetary ecosystem in general. Consequently, much recent research focuses on the effects of human activities on the atmosphere and, through them, on the environment and Earth's climate. For these reasons consideration of the geochemistry of the atmosphere, and of atmospheric aerosols in particular, must include the effects of human activities. (201K)Figure 1. Impairment of visibility by aerosols. Photographs at Yosemite National Park, California, USA. (a) Low aerosol concentration (particulate matter of aerodynamic diameter less than 2.5 μm, PM2.5=0.3 μg m-3; particulate matter of aerodynamic diameter less than 10

  12. Fingertip aura and interpersonal attraction.

    Science.gov (United States)

    Murstein, B I; Hadjolian, S E

    1977-06-01

    Concluding from our survey of the literature that fingertip auras (Kirlian effect) might be associated with interpersonal attraction, four hypotheses were advanced to test this assertion. It was hypothesized that individuals would respond with bigger auras to (1) opposite-sex photographers as compared to same-sex photographers, (2) to seductive opposite-sex photographers as opposed to normally behaving opposite-sex photographers, (3) to opposite-sex unknown peers as opposed to same-sex unknown peers, and (4) to liked as opposed to disliked same-sex persons. All hypotheses except (2) were supported. The second hypothesis was significant in a direction contrary to hypothesis. Fingertip auras are seen as a promising measurement device in the study of interpersonal attraction.

  13. Mission Status at Aura Science Team MOWG Meeting: EOS Aura

    Science.gov (United States)

    Fisher, Dominic

    2016-01-01

    Presentation at the 24797-16 Earth Observing System (EOS) Aura Science Team Meeting (Mission Operations Work Group (MOWG)) at Rotterdam, Netherlands August 29, 2016. Presentation topics include mission summary, spacecraft subsystems summary, recent and planned activities, spacecraft anomalies, data capture, propellant usage and lifetime estimates, spacecraft maneuvers and ground track history, mission highlights and past spacecraft anomalies and reliability estimates.

  14. The impact of air pollutant and methane emission controls on tropospheric ozone and radiative forcing: CTM calculations for the period 1990-2030

    Directory of Open Access Journals (Sweden)

    F. Dentener

    2005-01-01

    Full Text Available To explore the relationship between tropospheric ozone and radiative forcing with changing emissions, we compiled two sets of global scenarios for the emissions of the ozone precursors methane (CH4, carbon monoxide (CO, non-methane volatile organic compounds (NMVOC and nitrogen oxides (NOx up to the year 2030 and implemented them in two global Chemistry Transport Models. The 'Current Legislation' (CLE scenario reflects the current perspectives of individual countries on future economic development and takes the anticipated effects of presently decided emission control legislation in the individual countries into account. In addition, we developed a 'Maximum technically Feasible Reduction' (MFR scenario that outlines the scope for emission reductions offered by full implementation of the presently available emission control technologies, while maintaining the projected levels of anthropogenic activities. Whereas the resulting projections of methane emissions lie within the range suggested by other greenhouse gas projections, the recent pollution control legislation of many Asian countries, requiring introduction of catalytic converters for vehicles, leads to significantly lower growth in emissions of the air pollutants NOx, NMVOC and CO than was suggested by the widely used and more pessimistic IPCC (Intergovernmental Panel on Climate Change SRES (Special Report on Emission Scenarios scenarios (Nakicenovic et al., 2000, which made Business-as-Usual assumptions regarding emission control technology. With the TM3 and STOCHEM models we performed several long-term integrations (1990-2030 to assess global, hemispheric and regional changes in CH4, CO, hydroxyl radicals, ozone and the radiative climate forcings resulting from these two emission scenarios. Both models reproduce broadly the observed trends in CO, and CH4 concentrations from 1990 to 2002. For the 'current legislation' case, both models indicate an increase of the annual average ozone

  15. Exhaust emissions of volatile organic compounds of powered two-wheelers: effect of cold start and vehicle speed. Contribution to greenhouse effect and tropospheric ozone formation.

    Science.gov (United States)

    Costagliola, M Antonietta; Murena, Fabio; Prati, M Vittoria

    2014-01-15

    Powered two-wheeler (PTW) vehicles complying with recent European type approval standards (stages Euro 2 and Euro 3) were tested on chassis dynamometer in order to measure exhaust emissions of about 25 volatile organic compounds (VOCs) in the range C1-C7, including carcinogenic compounds as benzene and 1,3-butadiene. The fleet consists of a moped (engine capacity ≤ 50 cm(3)) and three fuel injection motorcycles of different engine capacities (150, 300 and 400 cm(3)). Different driving conditions were tested (US FPT cycle, constant speed). Due to the poor control of the combustion and catalyst efficiency, moped is the highest pollutant emitter. In fact, fuel injection strategy and three way catalyst with lambda sensor are able to reduce VOC motorcycles' emission of about one order of magnitude with respect to moped. Cold start effect, that is crucial for the assessment of actual emission of PTWs in urban areas, was significant: 30-51% of extra emission for methane. In the investigated speed range, moped showed a significant maximum of VOC emission factor at minimum speed (10 km/h) and a slightly decreasing trend from 20 to 60 km/h; motorcycles showed on the average a less significant peak at 10 km/h, a minimum at 30-40 km/h and then an increasing trend with a maximum emission factor at 90 km/h. Carcinogenic VOCs show the same pattern of total VOCs. Ozone Formation Potential (OFP) was estimated by using Maximum Incremental Reactivity scale. The greatest contribution to tropospheric ozone formation comes from alkenes group which account for 50-80% to the total OFP. VOC contribution effect on greenhouse effect is negligible with respect to CO2 emitted.

  16. Study on the Spatial and Temporal Variability of Stratosphere-Troposphere Exchange with A-Train Observations

    Science.gov (United States)

    Kollonige, D. W.; McMillan, W.; Sparling, L.; Avery, M.; Diskin, G.; Sachse, G.; Browell, E.; Hair, J. W.

    2008-12-01

    An understanding of isentropic transport of trace atmospheric constituents near the jet stream and frontal boundaries provides insight to the coupled stratosphere-troposphere system. Observations from NASA's A- Train satellites can assist in the determination of the global frequency, distribution and spatial extent of irreversible mixing of chemical species due to stratosphere-troposphere exchange (STE). The Tropospheric Emission Sounder (TES) and HIgh Resolution Dynamics Limb Sounder (HIRDLS) onboard the Aura satellite yield high vertical resolution profiles of ozone, water vapor, and other trace species that capture the vertical structure of STE along upper tropospheric fronts associated with the jet stream as well as cut-off low- pressure systems. The Atmospheric InfraRed Sounder (AIRS) onboard the Aqua satellite supplies wider horizontal coverage of the same atmospheric tracers near STE. Together, these A-Train instruments provide a more complete three-dimensional view of STE than previously possible. We explore the temporal and spatial evolution of STE events over the Pacific Ocean originating off the eastern coast of China and traveling along the storm track to the North American west coast, during NASA's Intercontinental Chemical Transport Experiment - Phase B (INTEX-B) in April and May of 2006. To study the variability of the STE events, we use chemical and dynamical analyses, including tracer-tracer correlations from A-Train observations and potential vorticity gradients from the NCEP's NARR (North American Regional Reanalysis) data in the vicinity of stratosphere-to-troposphere transport. We also compare our observations with in-situ and aircraft remote sensing measurements of similar trace gases evaluating the satellite instruments' sensitivity in the troposphere and stratosphere.

  17. Highlights from a Decade of OMI-TOMS Total Ozone Observations on EOS Aura

    Science.gov (United States)

    Haffner, David P.; Bhartia, Pawan K.; McPeters, Richard D.; Joiner, Joanna; Ziemke, Jerald R.; Vassilkov, Alexander; Labow, Gordon J.; Chiou, Er-Woon

    2014-01-01

    Total ozone measurements from OMI have been instrumental in meeting Aura science objectives. In the last decade, OMI has extended the length of the TOMS total ozone record to over 35 years to monitor stratospheric ozone recovery. OMI-TOMS total ozone measurements have also been combined synergistically with measurements from other Aura instruments and MLS in particular, which provides vertically resolved information that complements the total O3 mapping capability of OMI. With this combined approach, the EOS Aura platform has produced more accurate and detailed measurements of tropospheric ozone. This has led in turn to greater understanding of the sources and transport of tropospheric ozone as well as its radiative forcing effect. The combined use of OMI and MLS data was also vital to the analysis of the severe Arctic ozone depletion event of 2011. The quality of OMI-TOMS total O3 data used in these studies is the result of several factors: a mature and well-validated algorithm, the striking stability of the OMI instrument, and OMI's hyperspectral capabilities used to derive cloud pressures. The latter has changed how we think about the effects of clouds on total ozone retrievals. We will discuss the evolution of the operational V8.5 algorithm and provide an overview and motivation for V9. After reviewing results and developments of the past decade, we finally highlight how ozone observations from EOS Aura are playing an important role in new ozone mapping missions.

  18. Seasonal and spatial changes in trace gases over megacities from Aura TES observations: two case studies

    Science.gov (United States)

    Cady-Pereira, Karen E.; Payne, Vivienne H.; Neu, Jessica L.; Bowman, Kevin W.; Miyazaki, Kazuyuki; Marais, Eloise A.; Kulawik, Susan; Tzompa-Sosa, Zitely A.; Hegarty, Jennifer D.

    2017-08-01

    The Aura Tropospheric Emission Spectrometer (TES) is collecting closely spaced observations over 19 megacities. The objective is to obtain measurements that will lead to better understanding of the processes affecting air quality in and around these cities, and to better estimates of the seasonal and interannual variability. We explore the TES measurements of ozone, ammonia, methanol and formic acid collected around the Mexico City metropolitan area (MCMA) and in the vicinity of Lagos (Nigeria). The TES data exhibit seasonal signals that are correlated with Atmospheric Infrared Sounder (AIRS) CO and Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical depth (AOD), with in situ measurements in the MCMA and with Goddard Earth Observing System (GEOS)-Chem model output in the Lagos area. TES was able to detect an extreme pollution event in the MCMA on 9 April 2013, which is also evident in the in situ data. TES data also show that biomass burning has a greater impact south of the city than in the caldera where Mexico City is located. TES measured enhanced values of the four species over the Gulf of Guinea south of Lagos. Since it observes many cities from the same platform with the same instrument and applies the same retrieval algorithms, TES data provide a very useful tool for easily comparing air quality measures of two or more cities. We compare the data from the MCMA and Lagos, and show that, while the MCMA has occasional extreme pollution events, Lagos consistently has higher levels of these trace gases.

  19. Persistent Aura with Small Occipital Cortical Infarction: Implications for Migraine Pathophysiology

    Directory of Open Access Journals (Sweden)

    Sam Thissen

    2014-08-01

    Full Text Available Objective: The pathophysiology of migraine with aura is thought to be related to cortical spreading depression and cortical hypersensitivity, in which inhibitory interneurons may play a role. Persistent migraine aura (PMA without infarction is defined as auras that last longer than 1 week in the absence of infarction. We describe a case of persistent aura with a small occipital cortical infarction and discuss implications of this case and PMA for pathophysiological concepts of migrainous auras. Methods: We present a case and discuss the implications for pathophysiological concepts. Results: The case presented cannot be diagnosed as PMA as the patient was found to have an occipital cortical infarction with hypoactivity on fluorodeoxyglucose-positron emission tomography. Nevertheless, the patient suffered from persistent aura (with infarction. We argue that the infarction may have been responsible for an increased imbalance in one of the primary visual cortex networks that was already hyperexcitable due to the migraine aura condition. Conclusion: PMA with occipital infarction has not been reported previously. We believe the findings of the present case and PMA cases reported in the past may support the intracortical disinhibition hypothesis in migraine.

  20. Global peroxyacetyl nitrate (PAN retrieval in the upper troposphere from limb emission spectra of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS

    Directory of Open Access Journals (Sweden)

    N. Glatthor

    2007-06-01

    Full Text Available We use limb emission spectra of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS onboard the ENVIronmental SATellite (ENVISAT to derive the first global distribution of peroxyacetyl nitrate (PAN in the upper troposphere. PAN is generated in tropospheric air masses polluted by fuel combustion or biomass burning and acts as a reservoir and carrier of NOx in the cold free troposphere. PAN exhibits continuum-like broadband structures in the mid-infrared region and was retrieved in a contiguous analysis window covering the wavenumber region 775–800 cm−1. The interfering species CCl4, HCFC-22, H2O, ClONO2, CH3CCl3 and C2H2 were fitted along with PAN, whereas pre-fitted profiles were used to model the contribution of other contaminants like ozone. Sensitivity tests consisting in retrieval without consideration of PAN demonstrated the existence of PAN signatures in MIPAS spectra obtained in polluted air masses. The analysed dataset consists of 10 days between 4 October and 1 December 2003. This period covers the end of the biomass burning season in South America and South and East Africa, in which generally large amounts of pollutants are produced and distributed over wide areas of the southern hemispheric free troposphere. Indeed, elevated PAN amounts of 200–700 pptv were measured in a large plume extending from Brasil over the Southern Atlantic, Central and South Africa, the South Indian Ocean as far as Australia at altitudes between 8 and 16 km. Enhanced PAN values were also found in a much more restricted area between northern subtropical Africa and India. The most significant northern midlatitude PAN signal was detected in an area at 8 km altitude extending from China into the Chinese Sea. The average mid and high latitude PAN amounts found at 8 km were around 125 pptv in the northern, but only between 50 and 75 pptv in the

  1. Global peroxyacetyl nitrate (PAN retrieval in the upper troposphere from limb emission spectra of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS

    Directory of Open Access Journals (Sweden)

    N. Glatthor

    2007-01-01

    Full Text Available We use limb emission spectra of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS onboard the ENVIronmental SATellite (ENVISAT to derive the first global distribution of peroxyacetyl nitrate (PAN in the upper troposphere. PAN is generated in tropospheric air masses polluted by fuel combustion or biomass burning and acts as a reservoir and carrier of NOx in the cold free troposphere. Since PAN exhibits continuum-like broadband structures in the mid-infrared region, we have applied a contiguous analysis window covering the wavenumber region 775–800 cm−1 for retrieval. The interfering species CCl4, HCFC-22, H2O, ClONO2, CH3CCl3 and C2H2 were fitted along with PAN, whereas pre-fitted profiles were used to model the contribution of other contaminants like ozone. Sensitivity tests consisting in retrieval without consideration of PAN have demonstrated the existence of PAN signatures in MIPAS spectra obtained from polluted air masses. The analysed dataset consists of 10 days between 4 October and 1 December 2003. This period covers the end of the biomass burning season in South America and South and East Africa, in which generally large amounts of pollutants are produced and distributed over wide areas in the southern hemispheric free troposphere. Elevated PAN amounts of 200–700 pptv were measured in a large plume extending from Brasil over the Southern Atlantic, Central and South Africa, the South Indian Ocean as far as Australia at altitudes between 8 and 16 km. Enhanced PAN values were also found in a much more restricted area between northern subtropical Africa and India. The most significant northern midlatitude PAN signal in MIPAS data is an area extending at 8 km altitude from China into the Chinese Sea. The average mid and high latitude PAN amounts found at 8 km were around 125 pptv in the northern, but only between 75 and

  2. Influences of man-made emissions and climate changes on tropospheric ozone, methane, and sulfate at 2030 from a broad range of possible futures

    Science.gov (United States)

    Unger, Nadine; Shindell, Drew T.; Koch, Dorothy M.; Amann, Markus; Cofala, Janusz; Streets, David G.

    2006-06-01

    We apply the Goddard Institute for Space Studies composition-climate model to an assessment of tropospheric O3, CH4, and sulfate at 2030. We compare four different anthropogenic emissions forecasts: A1B and B1 from the Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios and Current Legislation (CLE) and Maximum Feasible Reduction (MFR) from the International Institute for Applied Systems Analysis. The projections encompass a wide range of possible man-made emissions changes. The A1B, B1, and CLE forecasts all suggest large increases in surface O3 and sulfate baseline pollution at tropical and subtropical latitudes, especially over the Indian subcontinent, where the pollution increases may be as large as 100%. The ranges of annual mean regional ground level O3 and sulfate changes across all scenarios are -10 to +30 ppbv and -1200 to +3000 pptv, respectively. Physical climate changes reduce future surface O3, but tend to increase ground level sulfate locally over North Africa because of an enhancement of aqueous-phase SO2 oxidation. For all examined future scenarios the combined sum of the CH4, O3, and sulfate radiative forcings is positive, even for the MFR scenario, because of the large reduction in sulfate. For A1B the forcings are as much as half of that of the preindustrial to present-day forcing for each species. For MFR the sign of the forcing for each species is reversed with respect to the other scenarios. At 2030, global changes in climate-sensitive natural emissions of CH4 from wetlands, NOx from lightning, and dimethyl sulfide from the ocean appear to be small (<5%).

  3. Trace gas constraints on vertical transport in models: a case study of Indonesian biomass burning emissions in 2006

    Science.gov (United States)

    Field, R. D.; Luo, M.; Worden, J.; Kim, D.; Del Genio, A. D.; Voulgarakis, A.

    2014-12-01

    We investigate the use of joint Aura TES and MLS CO retrievals in constraining vertical transport in the NASA GISS ModelE2 composition-climate model. We examine September to November 2006 over the tropics. El Nino-induced dry conditions over western Indonesia led to extensive biomass burning and persistent CO greater than 200 ppb in the upper troposphere. This was one of the highest CO episodes over the MLS period since 2004. We show how improvements in the vertical resolution of trace gas retrievals can help to distinguish between errors in parameterized vertical transport and biases in bottom-up emissions estimates. We simulate the episode using the NASA GISS ModelE2 coupled composition-climate model with different subgrid physics for small ensembles of experiments with perturbed initial conditions. The starting point is the CMIP5 version of the model, in which there was a pronounced vertical CO dipole over the Maritime Continent, but with a CO peak 100 ppb higher than Aura CO in the upper troposphere. With modified cumulus and boundary layer parameterizations, but the same prescribed biomass burning emissions estimates, the upper tropospheric CO bias is significantly reduced. Concurrently, precipitation over the emissions source region is reduced relative to observational estimates, leading to better consistency with the dry conditions under which the burning occurred. We discuss the effects of the physics changes on the roles of convective frequency and depth in reducing the bias.

  4. Clinical image: MRI during migraine with aura

    Energy Technology Data Exchange (ETDEWEB)

    McNeal, A.C. [Brooklyn VA Medical Center, NY (United States)

    1996-03-01

    Migraine refers to severe headaches that are usually unilateral, throbbing, and associated with nausea, vomiting, photophobia, and phonophobia. Migraine with aura (formerly called {open_quotes}classic migraine{close_quotes}) consists of the headache preceded or accompanied by neurological dysfunction. This dysfunction (aura) usually involves visual and sensory symptoms. The patient described herein experienced migraine with aura. MRI during and after the attack showed a reversible abnormality of the right posterior cerebral artery, with no parenchymal lesions. This appears to be the first report of abnormal MR vascular imaging during migraine with aura. 10 refs., 2 figs.

  5. Tropospheric ozone variability in the tropics from ENSO to MJO and shorter timescales

    OpenAIRE

    Ziemke, J. R.; Douglass, A.R.; L. D. Oman; S. E. Strahan; B. N. Duncan

    2015-01-01

    Aura OMI and MLS measurements are combined to produce daily maps of tropospheric ozone beginning October 2004. We show that El Niño-Southern Oscillation (ENSO) related inter-annual change in tropospheric ozone in the tropics is small in relation to combined intra-seasonal/Madden–Julian Oscillation (MJO) and shorter timescale variability by a factor of ~ 3–10 (largest in the Atlantic). Outgoing longwave radiation (OLR), taken as a proxy for convection, suggests that convectio...

  6. First Satellite Observations of Lower Tropospheric Ammonia and Methanol

    Science.gov (United States)

    Beer, Reinhard; Shephard, Mark W.; Kulawik, Susan S.; Clough, Shepard A.; Eldering, Annmarie; Bowman, Kevin W.; Sander, Stanley P.; Fisher, Brendan M.; Payne, Vivienne H.; Luo, Mingzhao; Osterman, Gregory B.; Worden, John R.

    2008-01-01

    The Tropospheric Emission Spectrometer (TES) on the EOS Aura satellite makes global measurements of infrared radiances which are used to derive profiles of species such as O3, CO, H2O, HDO and CH4 as routine standard products. In addition, TES has a variety of special modes that provide denser spatial mapping over a limited geographical area. A continuous-coverage mode (called ''transect'', about 460 km long) has now been used to detect additional molecules indicative of regional air pollution. On 10 July 2007 at about 05:37 UTC (13:24 LMST) TES conducted such a transect observation over the Beijing area in northeast China. Examination of the residual spectral radiances following the retrieval of the TES standard products revealed surprisingly strong features attributable to enhanced concentrations of ammonia (NH3) and methanol (CH3OH), well above the normal background levels. This is the first time that these molecules have been detected in space-based nadir viewing measurements that penetrate into the lower atmosphere.

  7. Next-Generation Aura/OMI NO2 and SO2 Products

    Science.gov (United States)

    Krotkov, Nickolay; Yang, Kai; Bucsela, Eric; Lamsal, Lok; Celarier, Edward; Swartz, William; Carn, Simon; Bhartia, Pawan; Gleason, James; Pickering, Ken; Dickerson, Russ

    2011-01-01

    The measurement of both SO2 and NO2 gases are recognized as an essential component of atmospheric composition missions. We describe current capabilities and limitations of the operational Aura/OMI NO2 and SO2 data that have been used by a large number of researchers. Analyses of the data and validation studies have brought to light a number of areas in which these products can be expanded and improved. Major improvements for new NASA standard (SP) NO2 product include more accurate tropospheric and stratospheric column amounts, along with much improved error estimates and diagnostics. Our approach uses a monthly NO2 climatology based on the NASA Global Modeling Initiative (GMI) chemistry-transport model and takes advantage of OMI data from cloudy scenes to find clean areas where the contribution from the trap NO2 column is relatively small. We then use a new filtering, interpolation and smoothing techniques for separating the stratospheric and tropospheric components of NO2, minimizing the influence of a priori information. The new algorithm greatly improves the structure of stratospheric features relative to the original SP. For the next-generation OMI SO2 product we plan to implement operationally the offline iterative spectral fitting (ISF) algorithm and re-process the OMI Level-2 SO2 dataset using a priori SO2 and aerosol profiles, clouds, and surface reflectivity appropriate for observation conditions. This will improve the ability to detect and quantify weak tropospheric SO2 loadings. The new algorithm is validated using aircraft in-situ data during field campaigns in China (2005 and 2008) and in Maryland (Frostburg, 2010 and DISCOVER-AQ in July 2011). The height of the SO2 plumes will also be estimated for high SO2 loading cases (e.g., volcanic eruptions). The same SO2 algorithm will be applied to the data from OMPS sensor to be launched on NPP satellite later this year. The next-generation NO2 and SO2 products will provide critical information (e

  8. Variability of tropospheric methane above the Mediterranean Basin inferred from satellite and model data

    Directory of Open Access Journals (Sweden)

    P. Ricaud

    2014-04-01

    Full Text Available The space and time variabilities of methane (CH4 total column and upper tropospheric mixing ratios are analyzed above the Mediterranean Basin (MB as part of the Chemical and Aerosol Mediterranean Experiment (ChArMEx programme. Spaceborne measurements from the Thermal And Near infrared Sensor for carbon Observations-Fourier Transform Spectrometer (TANSO-FTS instrument on the Greenhouse gases Observing SATellite (GOSAT satellite, the Atmospheric InfraRed Spectrometer (AIRS on the AURA platform and the Infrared Atmospheric Sounder Interferometer (IASI instrument aboard the MetOp-A platform are used in conjunction with model results from the Chemical Transport Model (CTM MOCAGE, and the Chemical Climate Models (CCMs CNRM-AOCCM and LMDz-OR-INCA (according to different emission scenarios. In order to minimize systematic errors in the spaceborne measurements, we have only considered maritime pixels over the MB. The period under interest spans from 2008 to 2011 considering satellite and MOCAGE data and, regarding the CCMs, from 2001 to 2010. An East-West gradient in CH4 is observed and modelled whatever the season considered. In winter, air masses mainly originating from Atlantic Ocean and Europe tend to favour an elevated amount of mid-to-upper tropospheric CH4 in the West vs. the East of the MB, with a general upward transport above the MB. In summer, the meteorological state of the MB is changed, favouring air from Northern Africa and Middle East together with Atlantic Ocean and Europe, with a general downward motion above the MB. The Asian Monsoon traps and uplifts high amounts of CH4 that are transported towards North Africa and Middle East by the Asian Monsoon Anticyclone to finally reach and descent in the East of the MB. Consequently, the mid-to-upper tropospheric CH4 is much greater in the East than in the West of the MB. The seasonal variation of the difference in CH4 between the East and the West MB does show a maximum in summer for pressures

  9. A Decade of Volcanic Observations from Aura and the A-Train

    Science.gov (United States)

    Carn, Simon A.; Krotkov, Nickolay Anatoly; Yang, Kai; Krueger, Arlin J.; Hughes, Eric J.; Wang, Jun; Flower, Verity; Telling, Jennifer

    2014-01-01

    Aura observations have made many seminal contributions to volcanology. Prior to the Aura launch, satellite observations of volcanic degassing (e.g., from TOMS) were mostly restricted to large eruptions. However, the vast majority of volcanic gases are released during quiescent 'passive' degassing between eruptions. The improved sensitivity of Aura OMI permitted the first daily, space-borne measurements of passive volcanic SO2 degassing, providing improved constraints on the source locations and magnitude of global SO2 emissions for input to atmospheric chemistry and climate models. As a result of this unique sensitivity to volcanic activity, OMI data were also the first satellite SO2 measurements to be routinely used for volcano monitoring at several volcano observatories worldwide. Furthermore, the Aura OMI SO2 data also offer unprecedented sensitivity to volcanic clouds in the UTLS, elucidating the transport, fate and lifetime of volcanic SO2 and providing critical input to aviation hazard mitigation efforts. Another major advance has been the improved vertical resolution of volcanic clouds made possible by synergy between Aura and other A-Train instruments (e.g., AIRS, CALIPSO, CloudSat), advanced UV SO2 altitude retrievals, and inverse trajectory modeling of detailed SO2 cloud maps. This altitude information is crucial for climate models and aviation hazards. We will review some of the highlights of a decade of Aura observations of volcanic activity and look ahead to the future of volcanic observations from space.

  10. Tropospheric observations of CFC-114 and CFC-114a with a focus on long-term trends and emissions

    Science.gov (United States)

    Laube, Johannes C.; Hanif, Norfazrin Mohd; Martinerie, Patricia; Gallacher, Eileen; Fraser, Paul J.; Langenfelds, Ray; Brenninkmeijer, Carl A. M.; Schwander, Jakob; Witrant, Emmanuel; Wang, Jia-Lin; Ou-Yang, Chang-Feng; Gooch, Lauren J.; Reeves, Claire E.; Sturges, William T.; Oram, David E.

    2016-12-01

    Chlorofluorocarbons (CFCs) are ozone-depleting substances as well as strong greenhouse gases, and the control of their production and use under the Montreal Protocol has had demonstrable benefits to both mitigation of increasing surface UV radiation and climate forcing. A global ban on consumption came into force in 2010, but there is evidence of continuing emissions of certain CFCs from a range of sources. One compound has received little attention in the literature, namely CFC-114 (C2Cl2F4). Of particular interest here is the differentiation between CFC-114 (CClF2CClF2) and its asymmetric isomeric form CFC-114a (CF3CCl2F) as atmospheric long-term measurements in the peer-reviewed literature to date have been assumed to represent the sum of both isomers with a time-invariant isomeric speciation. Here we report the first long-term measurements of the two isomeric forms separately, and find that they have different origins and trends in the atmosphere. Air samples collected at Cape Grim (41° S), Australia, during atmospheric background conditions since 1978, combined with samples collected from deep polar snow (firn) enable us to obtain a near-complete record of both gases since their initial production and release in the 1940s. Both isomers were present in the unpolluted atmosphere in comparably small amounts before 1960. The mixing ratio of CFC-114 doubled from 7.9 to 14.8 parts per trillion (ppt) between the start of the Cape Grim record in 1978 and the end of our record in 2014, while over the same time CFC-114a trebled from 0.35 to 1.03 ppt. Mixing ratios of both isomers are slowly decreasing by the end of this period. This is consistent with measurements of recent aircraft-based samples showing no significant interhemispheric mixing ratio gradient. We also find that the fraction of CFC-114a mixing ratio relative to that of CFC-114 increased from 4.2 to 6.9 % over the 37-year period. This contradicts the current tacit assumption used in international climate

  11. Can migraine aura be provoked experimentally?

    DEFF Research Database (Denmark)

    Lindblad, Marianne; Hougaard, Anders; Amin, Faisal Mohammad

    2017-01-01

    stimulation, physical activity, calcitonin gene-related peptide infusion, chocolate ingestion, and the intravenous injection of insulin. In addition, carotid artery puncture has consistently been reported as a trigger of aura. CONCLUSIONS: No safe and efficient method for aura provocation exists at present...

  12. Hemiplegic migraine aura begins with cerebral hypoperfusion

    DEFF Research Database (Denmark)

    Hansen, Jakob M; Schytz, Henrik W; Larsen, Vibeke A

    2011-01-01

    Imaging studies of spontaneous migraine aura have proved challenging because of the episodic and unpredictable nature of migraine attacks. Two patients with signs of acute ischemic stroke were evaluated for thrombolysis and turned out to suffer from familial hemiplegic migraine. It was possible...... to record the early phase of the hemiplegic aura with computed tomography with perfusion sequences and magnetic resonance imaging. We found cerebral hypoperfusion in the relevant cortical areas within the first hour after onset of aura symptoms. This report supports the concept that migraine aura across...... the migraine spectrum is caused by similar mechanisms. In a setting with efficient cooperation between headache and stroke neurologists, thrombolysis centers provide the set-up and opportunity to record aura symptoms at an early phase. Furthermore, in the time of ready access to acute systemic thrombolysis...

  13. Effects of the 2004 El Nino on Tropospheric Ozone and Water Vapor

    Science.gov (United States)

    Chandra, S.; Ziemke, J. R.; Schoeberl, M. R.; Froidevaux, L.; Read, W. G.; Levelt, P. F.; Bhartia, P. K.

    2007-01-01

    The global effects of the 2004 El Nino on tropospheric ozone and H2O based on Aura OM1 and MLS measurements are analyzed. Although it was a weak El Nino from a historical perspective, it produced significant changes in these parameters in tropical latitudes. Tropospheric ozone increased by 10-20% over most of the western Pacific region and decreased by about the same amount over the eastern Pacific region. H2O in the upper troposphere showed similar changes but with opposite sign. These zonal changes in tropospheric ozone and H2O are caused by the eastward shift in the Walker circulation in the tropical pacific region during El Nino. For the 2004 El Nino, biomass burning did not have a significant effect on the ozone budget in the troposphere unlike the 1997 El Nino. Zonally averaged tropospheric column ozone did not change significantly either globally or over the tropical and subtropical latitudes.

  14. [Migrainous aura subtypes in hospitalized children].

    Science.gov (United States)

    Biedroń, Agnieszka; Steczkowska, Małgorzata; Zajac, Anna; Stolarska, Urszula; Kroczka, Sławomir

    2009-01-01

    Migraine with aura is characterized by reversible focal neurological symptoms preceding or accompanying headache. Visual aura is the most common type of aura and its patognomic symptoms are scintillating fortification migrating across the visual field or scintillating scotoma. However, the symptoms are not always so typical and clinical doubts are greater when negative symptoms (loss of vision, numbness or paresis) are present. Differential diagnosis of migraine with aura includes in the first place transient ischemic attack (TIA) as well as epilepsy. Diagnosis of migraine in the developmental age is more difficult and associated with unprecise description of the symptoms. Thorough history taking is crucial in migraine diagnosis and following management. Knowledge of migraine with aura symptoms, clinical differences associated with developmental age and features enabling differentiation with other disorders imitating migraine is very important. Description of aura types and characteristics of migraine headache and their accompanying symptoms in children. 30 children were included, aged 8-17 years (mean 13,6 years), hospitalized at Department of Pediatric Neurology Chair of Pediatric and Adolescent Neurology, Jagiellonian University in 14 months of years 2008 and 2009. Clinical analysis was based on inquiry addressed to the patients and their parents. Migraine with visual aura was established in 9 patients, with somatosensory aura in 4, visual and somatosensory in 5, visual and dysphasic in 1, visual, somatosensory and dysphasic in 5, somatosensory and dysphasic in 2 and basilar type migraine in 4 patients. Consequently, symptoms of visual aura were present in 20/30 patients, in 9 of them it was the only type of aura and in 11 coexisted with other aura types. In more than half cases it manifested as simple visual phenomenons (spots, dots, frills, lines). Blurred vision was found in 5 patients (bilateral in 3, unilateral in 3) and hemianopia in 2 (bilateral in aura

  15. Radon activity in the lower troposphere and its impact on ionization rate: a global estimate using different radon emissions

    Directory of Open Access Journals (Sweden)

    K. Zhang

    2011-01-01

    Full Text Available The radioactive decay of radon and its progeny can lead to ionization of air molecules and consequently influence aerosol size distribution. In order to provide a global estimate of the radon-related ionization rate, we use the global atmospheric model ECHAM5 to simulate transport and decay processes of the radioactive tracers. A global radon emission map is put together using regional fluxes reported recently in the literature. The near-surface radon concentrations simulated with this new map compare well with measurements.

    Radon-related ionization rate is calculated and compared to that caused by cosmic rays. The contribution of radon and its progeny clearly exceeds that of the cosmic rays in the mid- and low-latitude land areas in the surface layer. In winter, strong radon-related ionization coincides with low temperature in China, USA, and Russia, providing favorable condition for the formation of aerosol particles. This suggests that it is probably useful to include the radon-induced ionization in global models when investigating the interaction between aerosol and climate.

  16. Information-centered representation of retrievals with limited degrees of freedom for signal: Application to methane from the Tropospheric Emission Spectrometer

    Science.gov (United States)

    Payne, Vivienne H.; Clough, Shepard A.; Shephard, Mark W.; Nassar, Ray; Logan, Jennifer A.

    2009-05-01

    Remote measurements of trace gas profiles from nadir-viewing instruments are often retrieved and/or reported on a fine grid containing more levels than the number of independent pieces of information in the measurement. Such profiles contain a priori information, which complicates interpretation. For scientific analyses of these data it is desirable to move to a representation in which measurement information is dominant and the influence of a priori information is minimal. Presented here is a postprocessing approach using a simple algorithm to transform each retrieved profile to an appropriate, geographically varying coarse grid. The representation is chosen such that the averaging kernel is close to unity for regions of the atmosphere where the retrieval has most information. The approach takes advantage of the sensitivity characterization allowed by retrieval on a fine grid, while reducing the influence of the a priori, accounting for spatial and temporal variations in the sensitivity of the measurement to the true atmosphere, and preserving obvious physical meaning in the end product. The example used to demonstrate the approach is the methane product from the Tropospheric Emission Spectrometer (TES), which contains 0.5-2.0 degrees of freedom for signal, depending on season and location. The TES methane has been postprocessed, and the end product has been compared with results from GEOS-Chem, a global chemical model. Results show realistic latitudinal gradients from the TES data. Model/measurement differences also show large-scale features over Indonesia that we attribute to tropical biomass burning in the summer/fall.

  17. A comparison of minor trace gas retrievals from the Tropospheric Emission Spectrometer (TES) and the Infrared Atmospheric Sounding Interferometer (IASI)

    Science.gov (United States)

    Cady-Pereira, K. E.; Shephard, M. W.; Henze, D. K.; Millet, D. B.; Gombos, D.; Van Damme, M.; Clarisse, L.; Coheur, P. F.; Pommier, M.; Clerbaux, C.

    2014-12-01

    The advent of hyperspectral infrared instruments orbiting the Earth has allowed for detecting and measuring numerous trace gas species that play important roles in atmospheric chemistry and impact air quality, but for which there is a dearth of information on their distribution and temporal variability. Here we will present global and regional comparisons of measurements from the NASA TES and the European MetOp IASI instruments of three of these gases: ammonia (NH3), formic acid (HCOOH) and methanol (CH3OH). Ammonia is highly reactive and thus very variable in space and time, while the sources and sinks of methanol and formic acid are poorly quantified: thus space-based measurements have the potential of significantly increasing our knowledge of the emissions and distributions of these gases. IASI and TES have many similarities but some significant differences. TES has significantly higher spectral resolution (0.06 cm-1), and its equator crossing times are ~1:30 am and 1:30 pm, local time, while IASI has lower resolution (0.5 cm-1) and an earlier equator crossing time (9:30 am and 9:30 pm), which leads to lower thermal contrast; however IASI provides much greater temporal and spatial coverage due to its cross-track scanning. Added to the instrumental differences are the differences in retrieval algorithms. The IASI team uses simple but efficient methods to estimate total column amounts of the species above, while the TES team performs full optimal estimation retrievals. We will compare IASI and TES total column measurements averaged on a 2.5x2.5 degree global grid for each month in 2009, and we will examine the seasonal cycle in some regions of interest, such as South America, eastern China, and the Midwest and the Central Valley in the US. In regions where both datasets are in agreement this analysis will provide confidence that the results are robust and reliable. In regions where there is disagreement we will look for the causes of the discrepancies, which will

  18. CH4 and CO distributions over tropical fires during October 2006 as observed by the Aura TES satellite instrument and modeled by GEOS-Chem

    Science.gov (United States)

    Worden, J.; Wecht, K.; Frankenberg, C.; Alvarado, M.; Bowman, K.; Kort, E.; Kulawik, S.; Lee, M.; Payne, V.; Worden, H.

    2013-04-01

    Tropical fires represent a highly uncertain source of atmospheric methane (CH4) because of the variability of fire emissions and the dependency of the fire CH4 emission factors (g kg-1 dry matter burned) on fuel type and combustion phase. In this paper we use new observations of CH4 and CO in the free troposphere from the Aura Tropospheric Emission Sounder (TES) satellite instrument to place constraints on the role of tropical fire emissions versus microbial production (e.g. in wetlands and livestock) during the (October) 2006 El Niño, a time of significant fire emissions from Indonesia. We first compare the global CH4 distributions from TES using the GEOS-Chem model. We find a mean bias between the observations and model of 26.3 ppb CH4 that is independent of latitude between 50° S and 80° N, consistent with previous validation studies of TES CH4 retrievals using aircraft measurements. The slope of the distribution of CH4 versus CO as observed by TES and modeled by GEOS-Chem is consistent (within the TES observation error) for air parcels over the Indonesian peat fires, South America, and Africa. The CH4 and CO distributions are correlated between R = 0.42 and R = 0.46, with these correlations primarily limited by the TES random error. Over Indonesia, the observed slope of 0.13 (ppb ppb-1) ±0.01, as compared to a modeled slope of 0.153 (ppb ppb-1) ±0.005 and an emission ratio used within the GEOS-Chem model of approximately 0.11 (ppb ppb-1), indicates that most of the observed methane enhancement originated from the fire. Slopes of 0.47 (ppb ppb-1) ±0.04 and 0.44 (ppb ppb-1) ±0.03 over South America and Africa show that the methane in the observed air parcels primarily came from microbial-generated emissions. Sensitivity studies using GEOS-Chem show that part of the observed correlation for the Indonesian observations and most of the observed correlations over South America and Africa are a result of transport and mixing of the fire and nearby microbial

  19. CH4 and CO distributions over tropical fires as observed by the Aura TES satellite instrument and modeled by GEOS-Chem

    Science.gov (United States)

    Worden, J.; Wecht, K.; Frankenberg, C.; Alvarado, M.; Bowman, K.; Kort, E.; Kulawik, S.; Lee, M.; Payne, V.; Worden, H.

    2012-10-01

    Tropical fires represent a highly uncertain source of atmospheric methane (CH4) because of the variability of fire emissions and the dependency of the fire CH4 emission factors (g kg-1 dry matter burned) on fuel type and combustion phase. In this paper we use new observations of CH4 and CO in the free troposphere from the Aura Tropospheric Emission Sounder (TES) satellite instrument to place constraints on the role of tropical fire emissions versus microbial production (e.g. in wetlands and livestock) during the (October) 2006 El Nino, a time of significant peat fire emissions from Indonesia We first evaluate the global CH4 distributions from TES using the GEOS-Chem model. We find a mean bias between the observations and model of 26.3 ppb CH4 that is independent of latitude between 50° S and 80° N consistent with previous validation studies of TES CH4 retrievals using aircraft measurements. The slope of the distribution of CH4 versus CO as observed by TES and modeled by GEOS-Chem is consistent (within the TES observation error) for air parcels over the Indonesian peat fires, South America, and Africa. The CH4 and CO distributions are correlated between R = 0.42 and R = 0.46, with these correlations primarily limited by the TES random error. Over Indonesia, the observed slope of 0.13 (ppb ppb-1) ± 0.01, as compared to a modeled slop of 0.153 (ppb ppb-1) ± 0.005 and an emission ratio used within the GEOS-Chem model of approximately 0.11 (ppb ppb-1) indicates that most of the observed methane enhancement originated from the fire. Slopes of 0.47 (ppb ppb-1) ± 0.04 and 0.44 (ppb ppb-1) ± 0.03 over South America and Africa show that the methane in the observed air parcels primarily came from microbial generated emissions. Sensitivity studies using GEOS-Chem show that part of the observed correlation for the Indonesian observations and most of the observed correlations over South America and Africa are a result of transport and mixing of the fire and nearby

  20. What have we learned about global SO2 pollution with Aura/OMI data?

    Science.gov (United States)

    Krotkov, N.; Yang, K.; Bhartia, P. K.; Carn, S.; Krueger, A.; Dickerson, R.; Li, C.

    2008-05-01

    Sulfur Dioxide (SO2) is a short-lived gas produced by volcanoes, power plants, refineries, metal smelting and general burning of fossil fuels. It is one of five EPA criteria pollutants. Emitted SO2 is soon converted to sulfate aerosol, with climate effects that include direct radiative forcing and aerosol-induced changes in cloud microphysics and the hydrological cycle. The Ozone Monitoring Instrument (OMI) launched on NASA Aura satellite in July 2004 offers unprecedented spatial resolution, coupled with contiguous daily global coverage, for space- based UV measurements of volcanic and anthropogenic SO2 emissions. Anthropogenic SO2 emissions in the PBL present challenges, because these typically weak signals need to be separated from the noise in the radiances. Plumes from strong surface sources of SO2 (such as smelters and coal burning power plants) and from strong regional pollution can currently be detected in the operational pixel data. Operational data were evaluated with in-situ aircraft SO2 profiles measured in the lower troposphere over China during the East-AIRE campaign in April 2005. This comparison demonstrates that OMI can distinguish between background SO2 conditions and heavy pollutions on a daily basis, suggesting potential of using OMI SO2 data for the regional pollution monitoring. Chinese SO2 pollution lofting above the PBL and long-range transport over Pacific Ocean was first confirmed using OMI data. Quantification of anthropogenic SO2 emissions requires off-line corrections of the average photon path, characterized by the operational air-mass factor (AMF). The AMF corrections in turn require a-priori information about the altitude of the SO2 plume center of mass, the total ozone, and surface albedo. In addition, aerosols and subpixel clouds affect the AMF in different ways depending on their amounts and vertical distribution. Therefore, ancillary cloud, snow and aerosol information available from near simultaneous A-train sensors is valuable

  1. Aura, Self, and Aesthetic Experience

    Directory of Open Access Journals (Sweden)

    Marshall Battani

    2011-01-01

    Full Text Available Aesthetic experiences are generated in encounters with cultural objects and such experiences are marked by the free play of cognitive and numinous experience unstructured by concepts. Kant’s famous three types of pleasure, made infamous in social theory by Pierre Bourdieu, are examined in relation to the critical theoretical concept of aura, the social psychology of “flow,” and cognitive explanations of perception to explain experience in aesthetic fields. Theories of aesthetic experience developed at the crossroad of critical social thought and cognitive science hold promise for a social analysis able to avoid the usual sociological pitfalls of either ignoring aesthetics or reducing it to structurally determined differences of taste.

  2. The Efficacy of Air Pollution Control Efforts: Evidence from AURA

    Science.gov (United States)

    Dickerson, Russell R.; Canty, Tim; Duncan, Bryan N.; Hao, He; Krotkov, Nickolay A.; Salawitch, Ross J.; Stehr, Jeffrey W.; Vinnikov, Konstatin

    2014-01-01

    Observations of NO2, SO2, and H2CO from OMI on AURA provide an excellent record of pollutant concentrations for the past decade. Abatement strategies to control criteria pollutants including ozone and fine particulate matter (PM2.5) have met with varying degrees of success. Sulfur controls had a profound impact on local SO2 concentrations and a measurable impact on PM2.5. Although substantial effort has gone into VOC control, ozone in the eastern US has responded dramatically to NOx emissions controls.

  3. Seasonal and spatial changes in trace gases over megacities from Aura TES observations: two case studies

    Directory of Open Access Journals (Sweden)

    K. E. Cady-Pereira

    2017-08-01

    Full Text Available The Aura Tropospheric Emission Spectrometer (TES is collecting closely spaced observations over 19 megacities. The objective is to obtain measurements that will lead to better understanding of the processes affecting air quality in and around these cities, and to better estimates of the seasonal and interannual variability. We explore the TES measurements of ozone, ammonia, methanol and formic acid collected around the Mexico City metropolitan area (MCMA and in the vicinity of Lagos (Nigeria. The TES data exhibit seasonal signals that are correlated with Atmospheric Infrared Sounder (AIRS CO and Moderate Resolution Imaging Spectroradiometer (MODIS aerosol optical depth (AOD, with in situ measurements in the MCMA and with Goddard Earth Observing System (GEOS-Chem model output in the Lagos area. TES was able to detect an extreme pollution event in the MCMA on 9 April 2013, which is also evident in the in situ data. TES data also show that biomass burning has a greater impact south of the city than in the caldera where Mexico City is located. TES measured enhanced values of the four species over the Gulf of Guinea south of Lagos. Since it observes many cities from the same platform with the same instrument and applies the same retrieval algorithms, TES data provide a very useful tool for easily comparing air quality measures of two or more cities. We compare the data from the MCMA and Lagos, and show that, while the MCMA has occasional extreme pollution events, Lagos consistently has higher levels of these trace gases.

  4. Cluster-like headache aura status

    NARCIS (Netherlands)

    Langedijk, M; van der Naalt, J; Luijckx, GJ; De Keyser, J

    2005-01-01

    We describe a patient with successive attacks (40 to 90 minutes) of cluster-like headache associated with aphasia, and contralateral hemihypesthesia and hemiplegia. The condition can best be described as cluster-like headache aura status.

  5. Cluster-like headache aura status

    NARCIS (Netherlands)

    Langedijk, M; van der Naalt, J; Luijckx, GJ; De Keyser, J

    2005-01-01

    We describe a patient with successive attacks (40 to 90 minutes) of cluster-like headache associated with aphasia, and contralateral hemihypesthesia and hemiplegia. The condition can best be described as cluster-like headache aura status.

  6. Perfusion patterns in migraine with aura.

    Science.gov (United States)

    Förster, Alex; Wenz, Holger; Kerl, Hans U; Brockmann, Marc A; Groden, Christoph

    2014-10-01

    Migraine with aura is a common neurological disorder, and differentiation from transient ischemic attack or stroke based on clinical symptoms may be difficult. From an MRI report database we identified 33 patients with migraine with aura and compared these to 33 age-matched ischemic stroke patients regarding perfusion patterns on perfusion-weighted imaging (PWI)-derived maps: time to peak (TTP), mean transit time (MTT), and cerebral blood flow and volume (CBF, CBV). In 18/33 (54.5%) patients with migraine with aura, TTP showed areas of hypoperfusion, most of these not limited to the territory of a specific artery but affecting two or more vascular territories. In patients with migraine with aura, TTP (1.09 ± 0.05 vs. 1.47 ± 0.40, p aura is usually associated with a perfusion deficit not limited to a specific vascular territory, and only a moderate increase of TTP. Thus, hypoperfusion restricted to a single vascular territory in combination with a marked increase of TTP or MTT may be regarded as atypical for migraine aura and suggestive of acute ischemic stroke. © International Headache Society 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  7. Evaluation of UTLS Carbon Monoxide Simulations in GMI and GEOS-Chem Chemical Transport Models using Aura MLS Observations

    Science.gov (United States)

    Huang, Lei; Jiang, Jonathan H.; Murray, Lee T.; Damon, Megan R.; Su, Hui; Livesey, Nathaniel J.

    2016-01-01

    This study evaluates the distribution and variation of carbon monoxide (CO) in the upper troposphere and lower stratosphere (UTLS) during 2004-2012 as simulated by two chemical transport models, using the latest version of Aura Microwave Limb Sounder (MLS) observations. The simulated spatial distributions, temporal variations and vertical transport of CO in the UTLS region are compared with those observed by MLS. We also investigate the impact of surface emissions and deep convection on CO concentrations in the UTLS over different regions, using both model simulations and MLS observations. Global Modeling Initiative (GMI) and GEOS-Chem simulations of UTLS CO both show similar spatial distributions to observations. The global mean CO values simulated by both models agree with MLS observations at 215 and 147 hPa, but are significantly underestimated by more than 40% at 100 hPa. In addition, the models underestimate the peak CO values by up to 70% at 100 hPa, 60% at 147 hPa and 40% at 215 hPa, with GEOS-Chem generally simulating more CO at 100 hPa and less CO at 215 hPa than GMI. The seasonal distributions of CO simulated by both models are in better agreement with MLS in the Southern Hemisphere (SH) than in the Northern Hemisphere (NH), with disagreements between model and observations over enhanced CO regions such as southern Africa. The simulated vertical transport of CO shows better agreement with MLS in the tropics and the SH subtropics than the NH subtropics. We also examine regional variations in the relationships among surface CO emission, convection and UTLS CO concentrations. The two models exhibit emission-convection- CO relationships similar to those observed by MLS over the tropics and some regions with enhanced UTLS CO.

  8. Evaluation of UTLS carbon monoxide simulations in GMI and GEOS-Chem chemical transport models using Aura MLS observations

    Science.gov (United States)

    Huang, Lei; Jiang, Jonathan H.; Murray, Lee T.; Damon, Megan R.; Su, Hui; Livesey, Nathaniel J.

    2016-05-01

    This study evaluates the distribution and variation of carbon monoxide (CO) in the upper troposphere and lower stratosphere (UTLS) during 2004-2012 as simulated by two chemical transport models, using the latest version of Aura Microwave Limb Sounder (MLS) observations. The simulated spatial distributions, temporal variations and vertical transport of CO in the UTLS region are compared with those observed by MLS. We also investigate the impact of surface emissions and deep convection on CO concentrations in the UTLS over different regions, using both model simulations and MLS observations. Global Modeling Initiative (GMI) and GEOS-Chem simulations of UTLS CO both show similar spatial distributions to observations. The global mean CO values simulated by both models agree with MLS observations at 215 and 147 hPa, but are significantly underestimated by more than 40 % at 100 hPa. In addition, the models underestimate the peak CO values by up to 70 % at 100 hPa, 60 % at 147 hPa and 40 % at 215 hPa, with GEOS-Chem generally simulating more CO at 100 hPa and less CO at 215 hPa than GMI. The seasonal distributions of CO simulated by both models are in better agreement with MLS in the Southern Hemisphere (SH) than in the Northern Hemisphere (NH), with disagreements between model and observations over enhanced CO regions such as southern Africa. The simulated vertical transport of CO shows better agreement with MLS in the tropics and the SH subtropics than the NH subtropics. We also examine regional variations in the relationships among surface CO emission, convection and UTLS CO concentrations. The two models exhibit emission-convection-CO relationships similar to those observed by MLS over the tropics and some regions with enhanced UTLS CO.

  9. Assessment and Applications of NASA Ozone Data Products Derived from Aura OMI-MLS Satellite Measurements in Context of the GMI Chemical Transport Model

    Science.gov (United States)

    Ziemke, J. R.; Olsen, M. A.; Witte, J. C.; Douglass, A. R.; Strahan, S. E.; Wargan, K.; Liu, X.; Schoeberl, M. R.; Yang, K.; Kaplan, T. B.; Pawson, S.; Duncan, B. N.; Newman, P. A.; Bhartia, K.; Heney, M. K.

    2013-01-01

    Measurements from the Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS), both onboard the Aura spacecraft, have been used to produce daily global maps of column and profile ozone since August 2004. Here we compare and evaluate three strategies to obtain daily maps of tropospheric and stratospheric ozone from OMI and MLS measurements: trajectory mapping, direct profile retrieval, and data assimilation. Evaluation is based upon an assessment that includes validation using ozonesondes and comparisons with the Global Modeling Initiative (GMI) chemical transport model (CTM). We investigate applications of the three ozone data products from near-decadal and inter-annual timescales to day-to-day case studies. Zonally averaged inter-annual changes in tropospheric ozone from all of the products in any latitude range are of the order 1-2 Dobson Units while changes (increases) over the 8-year Aura record investigated http://eospso.gsfc.nasa.gov/atbd-category/49 vary approximately 2-4 Dobson Units. It is demonstrated that all of the ozone products can measure and monitor exceptional tropospheric ozone events including major forest fire and pollution transport events. Stratospheric ozone during the Aura record has several anomalous inter-annual events including stratospheric warming split events in the Northern Hemisphere extra-tropics that are well captured using the data assimilation ozone profile product. Data assimilation with continuous daily global coverage and vertical ozone profile information is the best of the three strategies at generating a global tropospheric and stratospheric ozone product for science applications.

  10. Recent Large Reduction in Sulfur Dioxide Emissions from Chinese Power Plants Observed by the Ozone Monitoring Instrument

    Science.gov (United States)

    Li, Can; Zhang, Qiang; Krotkov, Nickolay A.; Streets, David G.; He, Kebin; Tsay, Si-Chee; Gleason, James F.

    2010-01-01

    The Ozone Monitoring Instrument (OMI) aboard NASA's Aura satellite observed substantial increases in total column SO2 and tropospheric column NO2 from 2005 to 2007, over several areas in northern China where large coal-fired power plants were built during this period. The OMI-observed SO2/NO2 ratio is consistent with the SO2/ NO2, emissions estimated from a bottom-up approach. In 2008 over the same areas, OMI detected little change in NO2, suggesting steady electricity output from the power plants. However, dramatic reductions of S0 2 emissions were observed by OMI at the same time. These reductions confirm the effectiveness of the flue-gas desulfurization (FGD) devices in reducing S02 emissions, which likely became operational between 2007 and 2008. This study further demonstrates that the satellite sensors can monitor and characterize anthropogenic emissions from large point sources.

  11. Characterization of consistent triggers of migraine with aura

    DEFF Research Database (Denmark)

    Hauge, Anne Werner; Kirchmann, Malene; Olesen, Jes

    2011-01-01

    The aim of the present study was to characterize perceived consistent triggers of migraine with aura (MA).......The aim of the present study was to characterize perceived consistent triggers of migraine with aura (MA)....

  12. Prevalence and characteristics of visual aura in idiopathic generalized epilepsy.

    Science.gov (United States)

    Gungor-Tuncer, Ozlem; Baykan, Betul; Altindag, Ebru; Bebek, Nerses; Gurses, Candan; Gokyigit, Aysen

    2012-12-01

    Some patients with idiopathic/genetic generalized epilepsy (IGE) experience visual aura, which can confuse the diagnosis. We sought to determine the frequency and characteristics of visual auras in IGE patients. Among the 176 IGE patients, 4 men and 7 women reported visual auras (mean age - 24 years). Syndromic diagnoses were juvenile myoclonic epilepsy in four, eyelid myoclonia with absences (EMA) in three, juvenile absence epilepsy in three, and other in one. Visual auras consisted of flashing lights, macropsia, illusional movements, and blindness. Eyelid myoclonia with absences was significantly more common in the group with visual aura (3 of 11 patients vs. 8 of 165 IGE patients; P=0.02). Furthermore, photosensitivity was found significantly more common in IGE patients with visual aura (90% vs 46% of the total IGE patients) (P=0.004). In conclusion, the visual auras do not exclude a diagnosis of IGE. The presence of visual aura in the EMA syndrome is also remarkable.

  13. Characterization of consistent triggers of migraine with aura

    DEFF Research Database (Denmark)

    Hauge, Anne Werner; Kirchmann, Malene; Olesen, Jes

    2011-01-01

    The aim of the present study was to characterize perceived consistent triggers of migraine with aura (MA).......The aim of the present study was to characterize perceived consistent triggers of migraine with aura (MA)....

  14. Aura in temporal lobe epilepsy: clinical and electroencephalographic correlation.

    OpenAIRE

    1983-01-01

    Patients with temporal lobe epilepsy were evaluated for their aura and the site of EEG abnormality. Autonomic and psychic auras were more frequently associated with right-sided temporal lobe lesions in 290 patients.

  15. A multi-sensor upper tropospheric ozone product (MUTOP based on TES Ozone and GOES water vapor: derivation

    Directory of Open Access Journals (Sweden)

    S. R. Felker

    2011-07-01

    Full Text Available The Tropospheric Emission Spectrometer (TES, a hyperspectral infrared instrument on the Aura satellite, retrieves a vertical profile of tropospheric ozone. However, polar-orbiting instruments like TES provide limited nadir-view coverage. This work illustrates the value of these observations when taken in context with geostationary imagery describing synoptic-scale weather patterns. The goal of this study is to create map-view products of upper troposphere (UT ozone through the integration of TES ozone measurements with two synoptic dynamic tracers of stratospheric influence: specific humidity derived from the GOES Imager water vapor absorption channel, and potential vorticity (PV from an operational forecast model. As a mixing zone between tropospheric and stratospheric reservoirs, the upper troposphere (UT exhibits a complex chemical makeup. Determination of ozone mixing ratios in this layer is especially difficult without direct in situ measurement. However, it is well understood that UT ozone is correlated with dynamical tracers like low specific humidity and high potential vorticity. Blending the advantages of two remotely sensed quantities (GOES water vapor and TES ozone is at the core of the Multi-sensor Upper Tropospheric Ozone Product (MUTOP.

    Our results suggest that 72 % of TES-observed UT ozone variability can be explained by its correlation with dry air and high PV. MUTOP reproduces TES retrievals across the GOES-West domain with a root mean square error (RMSE of 18 ppbv (part per billion by volume. There are several advantages to this multi-sensor derived product approach: (1 it is calculated from two operational fields (GOES specific humidity and GFS PV, so maps of layer-average ozone can be created and used in near real-time; (2 the product provides the spatial resolution and coverage of a geostationary image as it depicts the variable distribution of ozone in the UT; and (3 the 6 h temporal resolution of the derived

  16. A Multi-sensor Upper Tropospheric Ozone Product (MUTOP based on TES ozone and GOES water vapor: derivation

    Directory of Open Access Journals (Sweden)

    S. R. Felker

    2010-12-01

    Full Text Available The Tropospheric Emission Spectrometer (TES, a hyperspectral infrared instrument on the Aura satellite, retrieves a vertical profile of tropospheric ozone. However, polar-orbiting instruments like TES provide limited nadir-view coverage. This work illustrates the value of these observations when taken in context with information about synoptic-scale weather patterns. The goal of this study is to create map-view products of upper troposphere (UT ozone through the integration of TES ozone measurements with two synoptic dynamical tracers of stratospheric influence: specific humidity derived from the GOES Imager, and potential vorticity from an operational forecast model. As a mixing zone between tropospheric and stratospheric reservoirs, the upper troposphere (UT exhibits a complex chemical makeup. Determination of ozone mixing ratios in this layer is especially difficult without direct in-situ measurement. However, it is well understood that UT ozone is correlated with dynamical tracers like low specific humidity and high potential vorticity. Blending the advantages of two remotely sensed quantities (GOES water vapor and TES ozone is at the core of the Multi-sensor Upper Tropospheric Ozone Product (MUTOP.

    Our approach results in the temporal and spatial coverage of a geostationary platform, a major improvement over individual polar overpasses, while retaining TES's ability to characterize UT ozone. Results suggest that over 70% of TES-observed UT ozone variability can be explained by correlation with the two dynamical tracers. MUTOP reproduces TES retrievals across the GOES-West domain with a root mean square error (RMSE of 19.2 ppbv. There are several advantages to this multi-sensor derived product approach: (1 it is calculated from 2 operational fields (GOES specific humidity and GFS PV, so the layer-average ozone can be created and used in near real-time; (2 the product provides the spatial resolution and coverage of a geostationary

  17. Hydrological controls on the tropospheric ozone greenhouse gas effect

    OpenAIRE

    Kuai, Le; Bowman, Kevin W.; Worden, Helen M.; Herman, Robert L.; Susan S. Kulawik

    2017-01-01

    The influence of the hydrological cycle in the greenhouse gas (GHG) effect of tropospheric ozone (O3) is quantified in terms of the O3longwave radiative effect (LWRE), which is defined as the net reduction of top-of-atmosphere flux due to total tropospheric O3absorption. The O3LWRE derived from the infrared spectral measurements by Aura’s Tropospheric Emission Spectrometer (TES) show that the spatiotemporal variation of LWRE is relevant to relative humidity, surface temperature, and troposphe...

  18. Trigger factors in migraine with aura

    DEFF Research Database (Denmark)

    Hauge, A W; Hauge, Anne Werner; Kirchmann, M

    2010-01-01

    The aim of the present study was to identify trigger factors in migraine with aura (MA). A total of 629 MA patients representative of the Danish population were sent a questionnaire listing 16 trigger factors thought to be relevant as well as space for free text. Distinction was made between...... attacks with or without aura within each patient. The questionnaire was returned by 522 patients of whom 347 had current MA attacks. In total 80% with current attacks (278/347) indicated that at least one factor triggered their migraine, and 67% (187/278) in this group indicated that they were aware...... of at least one factor often or always giving rise to an attack of MA. Forty-one per cent (113/278) had co-occurring attacks of migraine without aura (MO). Stress (following stress), bright light, intense emotional influences, stress (during stress) and sleeping too much or too little were the trigger factors...

  19. Simulating the Black Saturday 2009 smoke plume with an interactive composition-climate model: Sensitivity to emissions amount, timing, and injection height

    Science.gov (United States)

    Field, Robert D.; Luo, Ming; Fromm, Mike; Voulgarakis, Apostolos; Mangeon, Stéphane; Worden, John

    2016-04-01

    We simulated the high-altitude smoke plume from the early February 2009 Black Saturday bushfires in southeastern Australia using the NASA Goddard Institute for Space Studies ModelE2. To the best of our knowledge, this is the first single-plume analysis of biomass burning emissions injected directly into the upper troposphere/lower stratosphere (UTLS) using a full-complexity composition-climate model. We compared simulated carbon monoxide (CO) to a new Aura Tropospheric Emission Spectrometer/Microwave Limb Sounder joint CO retrieval, focusing on the plume's initial transport eastward, anticyclonic circulation to the north of New Zealand, westward transport in the lower stratospheric easterlies, and arrival over Africa at the end of February. Our goal was to determine the sensitivity of the simulated plume to prescribed injection height, emissions amount, and emissions timing from different sources for a full-complexity model when compared to Aura. The most realistic plumes were obtained using injection heights in the UTLS, including one drawn from ground-based radar data. A 6 h emissions pulse or emissions tied to independent estimates of hourly fire behavior produced a more realistic plume in the lower stratosphere compared to the same emissions amount being released evenly over 12 or 24 h. Simulated CO in the plume was highly sensitive to the differences between emissions amounts estimated from the Global Fire Emissions Database and from detailed, ground-based estimates of fire growth. The emissions amount determined not only the CO concentration of the plume but also the proportion of the plume that entered the stratosphere. We speculate that this is due to either or both nonlinear CO loss with a weakened OH sink or plume self-lofting driven by shortwave absorption of the coemitted aerosols.

  20. EOS Aura and Future Satellite Studies of the Ozone Layer

    Science.gov (United States)

    Schoeberl, Mark R.

    2007-01-01

    The EOS Aura mission, launched in 2004, provides a comprehensive assessment of the stratospheric dynamics and chemistry. This talk will focus on results from Aura including the chemistry of polar ozone depletion. The data from Aura can be directly linked to UARS data to produce long term trends in stratospheric trace gases.

  1. Hemiplegic migraine aura begins with cerebral hypoperfusion

    DEFF Research Database (Denmark)

    Hansen, Jakob M; Schytz, Henrik W; Larsen, Vibeke A

    2011-01-01

    Imaging studies of spontaneous migraine aura have proved challenging because of the episodic and unpredictable nature of migraine attacks. Two patients with signs of acute ischemic stroke were evaluated for thrombolysis and turned out to suffer from familial hemiplegic migraine. It was possible...... the migraine spectrum is caused by similar mechanisms. In a setting with efficient cooperation between headache and stroke neurologists, thrombolysis centers provide the set-up and opportunity to record aura symptoms at an early phase. Furthermore, in the time of ready access to acute systemic thrombolysis...

  2. Assimilation of Aura Ozone Data and Comparisons with In Situ Observations

    Science.gov (United States)

    Stajner, Ivanka; Wargan, Krzysztof; Pawson, Steven

    2008-01-01

    Ozone data from the Ozone Monitoring Instrument (OMI) and the Microwave Limb Sounder (MLS) onboard EOS Aura satellite were assimilated into the Goddard Earth Observing System Version 4 (GEOS-4) ozone assimilation system. Comparison of assimilated ozone with ozone sonde and MOZAIC data indicate an agreement within 10% in the lower stratosphere, where dynamical processes dominate. Assimilation of OMI and MLS data improves tropospheric column estimates in the Atlantic region, but leads to an overestimation in the tropical Pacific in comparison with SHADOZ sondes. Transport and data biases are considered in order to understand these discrepancies. Comparisons of assimilated tropospheric ozone columns with ozone sonde data reveal root-mean-square (RMS) differences of 2.9 to 7.2 DU, which are typically smaller than the model-sonde RMS differences. Four different definitions of the tropopause using temperature lapse rate, potential vorticity (PV) and isentropic surfaces or ozone isosurfaces are compared with respect to their global impact on the estimated tropospheric ozone column. The largest sensitivity in the tropospheric ozone column is found near the subtropical jet, where the ozone or PV determined tropopause typically lies below the lapse rate tropopause.

  3. Assimilation of Aura Ozone Data and Comparisons with In Situ Observations

    Science.gov (United States)

    Stajner, Ivanka; Wargan, Krzysztof; Pawson, Steven

    2008-01-01

    Ozone data from the Ozone Monitoring Instrument (OMI) and the Microwave Limb Sounder (MLS) onboard EOS Aura satellite were assimilated into the Goddard Earth Observing System Version 4 (GEOS-4) ozone assimilation system. Comparison of assimilated ozone with ozone sonde and MOZAIC data indicate an agreement within 10% in the lower stratosphere, where dynamical processes dominate. Assimilation of OMI and MLS data improves tropospheric column estimates in the Atlantic region, but leads to an overestimation in the tropical Pacific in comparison with SHADOZ sondes. Transport and data biases are considered in order to understand these discrepancies. Comparisons of assimilated tropospheric ozone columns with ozone sonde data reveal root-mean-square (RMS) differences of 2.9 to 7.2 DU, which are typically smaller than the model-sonde RMS differences. Four different definitions of the tropopause using temperature lapse rate, potential vorticity (PV) and isentropic surfaces or ozone isosurfaces are compared with respect to their global impact on the estimated tropospheric ozone column. The largest sensitivity in the tropospheric ozone column is found near the subtropical jet, where the ozone or PV determined tropopause typically lies below the lapse rate tropopause.

  4. Aura OMI Observations of Global SO2 and NO2 Pollution from 2005 to 2013

    Science.gov (United States)

    Krotkov, Nickolay; Li, Can; Lamsal, Lok; Celarier, Edward; Marchenko, Sergey; Swartz, William H.; Bucsela, Eric; Fioletov, Vitali; McLinden, Chris; Joiner, Joanna; Bhartia, Pawan K.; Duncan, Bryan; Dickerson, Russ

    2014-01-01

    The Ozone Monitoring Instrument (OMI), a NASA partnership with the Netherlands and Finland, flies on the NASA Aura satellite and uses reflected sunlight to measure the two critical atmospheric trace gases: nitrogen dioxide (NO2) and sulfur dioxide (SO2) characterizing daily air quality. Both gases and the secondary pollutants they produce (particulate matter, PM2.5, and tropospheric ozone) are USEPA designated criteria pollutants, posing serious threats to human health and the environment (e.g., acid rain, plant damage and reduced visibility). Our group at NASA GSFC has developed and maintained OMI standard SO2 and NO2 data products. We have recently released an updated version of the standard NO2 L2 and L3 products (SP v2.1) and continue improving the algorithm. We are currently in the process of releasing next generation pollution SO2 product, based on an innovative Principal Component Analysis (PCA) algorithm, which greatly reduces the noise and biases. These new standard products provide valuable datasets for studying anthropogenic pollution on local to global scales. Here we highlight some of the OMI observed changes in air quality over several regions. Over the US average NO2 and SO2 pollution levels had decreased dramatically as a result of both technological improvements (e.g., catalytic converters on cars) and stricter regulations of emissions. We see continued decline in pollution over Europe. Over China OMI observed an increase of about 60 percent in NO2 pollution between 2005 and 2013, despite a temporal reversal of the growing trend due to both 2008 Olympic Games and the economic recession in 2009. Chinese SO2 pollution seems to have stabilized since peaking in 2007, probably due to government efforts to curb SO2 emissions from the power sector. We have also observed large increases in both SO2 and NO2 pollution particularly in Eastern India where a number of large new coal power plants had been built in recent years. We expect that further

  5. Observations of volcanic SO2 from MLS on Aura

    Directory of Open Access Journals (Sweden)

    H. C. Pumphrey

    2014-07-01

    Full Text Available Sulphur dioxide (SO2 is an important atmospheric constituent, particularly in the aftermath of volcanic eruptions. These events can inject large amounts of SO2 into the lower stratosphere, where it is oxidised to form sulphate aerosols; these in turn have a significant effect on the climate. The MLS instrument on the Aura satellite has observed the SO2 mixing ratio in the upper troposphere and lower stratosphere from August 2004 to the present, during which time a number of volcanic eruptions have significantly affected those regions of the atmosphere. We describe the MLS SO2 data and how various volcanic events appear in the data. As the MLS SO2 data are currently not validated we take some initial steps towards their validation. First we establish the level of internal consistency between the three spectral regions in which MLS is sensitive to SO2. We compare SO2 column values calculated from MLS data to total column values reported by the OMI instrument. The agreement is good in cases where the SO2 is clearly at altitudes above 147 hPa.

  6. Observations of volcanic SO2 from MLS on Aura

    Directory of Open Access Journals (Sweden)

    H. C. Pumphrey

    2015-01-01

    Full Text Available Sulfur dioxide (SO2 is an important atmospheric constituent, particularly in the aftermath of volcanic eruptions. These events can inject large amounts of SO2 into the lower stratosphere, where it is oxidised to form sulfate aerosols; these in turn have a significant effect on the climate. The MLS instrument on the Aura satellite has observed the SO2 mixing ratio in the upper troposphere and lower stratosphere from August 2004 to the present, during which time a number of volcanic eruptions have significantly affected those regions of the atmosphere. We describe the MLS SO2 data and how various volcanic events appear in the data. As the MLS SO2 data are currently not validated we take some initial steps towards their validation. First we establish the level of internal consistency between the three spectral regions in which MLS is sensitive to SO2. We compare SO2 column values calculated from MLS data to total column values reported by the OMI instrument. The agreement is good (within about 1 DU in cases where the SO2 is clearly at altitudes above 147 hPa.

  7. Can migraine aura be provoked experimentally? A systematic review of potential methods for the provocation of migraine aura.

    Science.gov (United States)

    Lindblad, Marianne; Hougaard, Anders; Amin, Faisal Mohammad; Ashina, Messoud

    2017-01-01

    Background The nature of the migraine aura and its role in migraine pathophysiology is incompletely understood. In particular, the mechanisms underlying aura initiation and the causal relation between aura and headache are unknown. The scientific investigation of aura in patients is only possible if aura can be triggered. This paper reviews potential methods for the experimental provocation of migraine aura. Methods We systematically searched PubMed for studies of experimental migraine provocation, including case reports of patients with aura and reports of the occurrence of aura following exposure to any kind of suspected trigger. Results We identified 21 provocation studies, using 13 different prospective provocation methods, and 34 case reports. In the prospective studies, aura were reported following the administration of intravenous and sublingual glyceryl trinitrate, visual stimulation, physical activity, calcitonin gene-related peptide infusion, chocolate ingestion, and the intravenous injection of insulin. In addition, carotid artery puncture has consistently been reported as a trigger of aura. Conclusions No safe and efficient method for aura provocation exists at present, but several approaches could prove useful for this purpose.

  8. Carbon monoxide distributions from the upper troposphere to the mesosphere inferred from 4.7 μm non-local thermal equilibrium emissions measured by MIPAS on Envisat

    Directory of Open Access Journals (Sweden)

    B. Funke

    2009-04-01

    Full Text Available We present global distributions of carbon monoxide (CO from the upper troposphere to the mesosphere observed by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS on Envisat. Vertically resolved volume mixing ratio profiles have been retrieved from 4.7 μm limb emission spectra under consideration of non-local thermodynamic equilibrium. The precision of individual CO profiles is typically 5–30 ppbv (15–40% for altitudes greater than 40 km and lower than 15 km and 30–90% within 15–40 km. Estimated systematic errors are in the order of 8–15%. Below 60 km, the vertical resolution is 4–7 km. The data set which covers 54 days from September 2003 to March 2004 has been derived with an improved retrieval version including (i the retrieval of log(vmr, (ii the consideration of illumination-dependent vibrational population gradients along the instrument's line of sight, and (iii joint-fitted vmr horizontal gradients in latitudinal and longitudinal directions. A detailed analysis of spatially resolved CO distributions during the 2003/2004 Northern Hemisphere major warming event demonstrate the potential of MIPAS CO observations to obtain new information on transport processes during dynamical active episodes, particularly on those acting in the vertical. From the temporal evolution of zonally averaged CO abundances, we derived extraordinary polar winter descent velocities of 1200 m per day inside the recovered polar vortex in January 2004. Middle stratospheric CO abundances show a well established correlation with the chemical source CH4, particularly in the tropics. In the upper troposphere, a moderate CO decrease from September 2003 to March 2004 was observed. Upper tropospheric CO observations provide a detailed picture of long-range transport of polluted air masses and uplift events. MIPAS observations taken on 9–11 September 2003 confirm the trapping of convective outflow of polluted CO-rich air from

  9. Ozone columns obtained by ground-based remote sensing in Kiev for Aura Ozone Measuring Instrument validation

    Science.gov (United States)

    Shavrina, A. V.; Pavlenko, Y. V.; Veles, A.; Syniavskyi, I.; Kroon, M.

    2007-12-01

    Ground-based observations with a Fourier transform spectrometer in the infrared region (FTIR) were performed in Kiev (Ukraine) during the time frames August-October 2005 and June-October 2006 within the Ozone Monitoring Instrument (OMI) validation project 2907 entitled "OMI validation by ground based remote sensing: ozone columns and profiles" in the frame of the international European Space Agency/Netherlands Agency for Aerospace Programmes/Royal Dutch Meteorological Institute OMI Announcement of Opportunity effort. Ozone column data for 2005 were obtained by modeling the ozone spectral band at 9.6 μm with the radiative transfer code MODTRAN3.5. Our total ozone column values were found to be lower than OMI Differential Optical Absorption Spectroscopy (DOAS) total ozone column data by 8-10 Dobson units (DU, 1 DU = 0.001 atm cm) on average, while our observations have a relatively small standard error of about 2 DU. Improved modeling of the ozone spectral band, now based on HITRAN-2004 spectral data as calculated by us, moves our results toward better agreement with the OMI DOAS total ozone column data. The observations made during 2006 with a modernized FTIR spectrometer and higher signal-to-noise ratio were simulated by the MODTRAN4 model computations. For ozone column estimates the Aqua Atmospheric Infrared Sounder satellite water vapor and temperature profiles were combined with the Aura Microwave Limb Sounder stratospheric ozone profiles and Tropospheric Emission Monitoring Internet Service-Koninklijk Nederlands Meteorologisch Instituut climatological profiles to create a priori input files for spectral modeling. The MODTRAN4 estimates of ozone columns from the 2006 observations compare rather well with the OMI total ozone column data: standard errors are of 1.11 DU and 0.68 DU, standard deviation are of 8.77 DU and 5.37 DU for OMI DOAS and OMI Total Ozone Mapping Spectrometer, respectively.

  10. Estimate of bias in Aura TES HDO/H2O profiles from comparison of TES and in situ HDO/H2O measurements at the Mauna Loa Observatory

    Directory of Open Access Journals (Sweden)

    J. Lee

    2010-11-01

    Full Text Available The Aura satellite Tropospheric Emission Spectrometer (TES instrument is capable of measuring the HDO/H2O ratio in the lower troposphere using thermal infrared radiances between 1200 and 1350 cm−1. However, direct validation of these measurements is challenging due to a lack of in situ measured vertical profiles of the HDO/H2O ratio that are spatially and temporally co-located with the TES observations. From 11 October through 5 November 2008, we undertook a campaign to measure HDO and H2O at the Mauna Loa observatory in Hawaii for comparison with TES observations. The Mauna Loa observatory is situated at 3.1 km above sea level or approximately 680 hPa, which is approximately the altitude where the TES HDO/H2O observations show the most sensitivity. Another advantage of comparing in situ data from this site to estimates derived from thermal IR radiances is that the volcanic rock is heated by sunlight during the day, thus providing significant thermal contrast between the surface and atmosphere; this thermal contrast increases the sensitivity to near surface estimates of tropospheric trace gases. The objective of this inter-comparison is to better characterize a bias in the TES HDO data, which had been previously estimated to be approximately 5% too high for a column integrated value between 850 hPa and 500 hPa. We estimate that the TES HDO profiles should be corrected downwards by approximately 4.1% and 5.6% for Versions 3 and 4 of the data, respectively. These corrections must account for the vertical sensitivity of the TES HDO estimates. We estimate that the uncertainty of this bias correction is approximately 1%. However, future comparisons of TES data to other sensors are needed to refine this bias estimate because these uncertainties are primarily derived from only three sets of measurements.

  11. Is Ciliary Muscle Affected in Migraine Patients with Aura and without Aura?

    Science.gov (United States)

    Kıvanç, Sertaç Argun; Ulusoy, Mahmut Oğuz; Akova-Budak, Berna; Olcaysu, Osman Okan; Özcan, Muhammed Emin

    2015-01-01

    Background The aim of this study was to compare spherical equivalents (SE) and spherical equivalents with cycloplegic (CSE) values of migraine patients with and without visual aura, with those patients without migraine complaints. Material/Methods We included patients over the age of 18 years, who had 20/20 uncorrected vision, and who did not have ocular pathology in their examination. The patients were divided into 3 groups: Group 1: 86 eyes of 43 migraine patients without aura, Group 2: 38 eyes of 19 migraine patients with aura, and Group 3: 60 eyes of 30 patients without migraine. Spherical equivalents and spherical equivalents with cycloplegic from the auto-refractometrical values of the patients were compared. Results The mean age of the migraine and control patients was 34.2±8.3 and 33.6±10.8 years, respectively. Forty-three (69%) of 62 migraine patients had migraine without aura and 19 (31%) had migraine with aura. The right and left eyes of the patients were evaluated together and a significant correlation was found between the groups. To evaluate the impact of cycloplegia in patients, SE and CSE values were obtained and differences between these values were evaluated. It was found that the change in Group 2 patients was significantly lower than the change in Group 3 patients (p=0.024). Conclusions We found that the cycloplegic spherical equivalents values of our patients with aura were lower than control patients. We need further studies to reveal whether migraine with aura is the trigger or the result of those attacks. PMID:25919450

  12. Aura-like features and photophobia in sightless migraine patients

    Directory of Open Access Journals (Sweden)

    Greice Cardoso de Carvalho Silva

    2014-12-01

    Full Text Available Migraine is a central nervous system disorder frequently expressed with paroxysmal visual dysfunctions. Objective To test the hypothesis that normal visual input is vital for the migrainous aura and photophobia. Method We studied the migraine-related visual disturbances in 8 sightless migraineurs identified among 200 visually impaired subjects. Results The main findings were the visual aura and photophobia disappearance along with blindness development, the oddness of aura – too short, colourful (e.g. blue or fire-like, auditory in nature or different in shape (round forms – and the lack of photophobia. Conclusion We propose that the aura duration should be accepted as shorter in visually impaired subjects. The changes in aura phenotype observed in our patients may be the result of both cerebral plasticity induced by the visual impairment and/or the lack of visual input per se. Integrity of visual pathways plays a key role in migraine visual aura and photophobia.

  13. Aura-like features and photophobia in sightless migraine patients.

    Science.gov (United States)

    Silva, Greice Cardoso de Carvalho; Góes, Cristiana Pessoa de Queiroz Faria; Vincent, Maurice Borges

    2014-12-01

    Migraine is a central nervous system disorder frequently expressed with paroxysmal visual dysfunctions. To test the hypothesis that normal visual input is vital for the migrainous aura and photophobia. We studied the migraine-related visual disturbances in 8 sightless migraineurs identified among 200 visually impaired subjects. The main findings were the visual aura and photophobia disappearance along with blindness development, the oddness of aura - too short, colourful (e.g. blue or fire-like), auditory in nature or different in shape (round forms) - and the lack of photophobia. We propose that the aura duration should be accepted as shorter in visually impaired subjects. The changes in aura phenotype observed in our patients may be the result of both cerebral plasticity induced by the visual impairment and/or the lack of visual input per se. Integrity of visual pathways plays a key role in migraine visual aura and photophobia.

  14. Hypomania as an aura in migraine

    Directory of Open Access Journals (Sweden)

    Datta Soumitra

    2006-01-01

    Full Text Available We report a 19-year-old man presenting to the department of Psychiatry for the evaluation of prominent behavioral symptoms associated with episodic headaches, with normal inter-episodic periods. A diagnosis of classic migraine with hypomanic aura was made. Other possible co-morbid or causative illnesses were excluded and preventive therapy with valproate was started due to the prominent affective symptoms as a part of the migranous aura. With this the frequency of headaches gradually decreased over the next four months. He was followed up for 2 years when he was found to be symptom-free. Recent research into the mechanisms of migraine has identified that the cortical hyperexcitability and an imbalance between neuronal inhibition and excitement mediated by gamma-aminobutyric acid and excitatory amino acids respectively may be the underlying mechanism. The high rate of affective disorders in patients with migraine, association of migraine with an aura comprising of mood symptoms and good response to treatment with mood-stabilisers might give newer insights into the pathophysiology of mood disorder as well.

  15. On the methodology of drug trials in migraine with aura

    DEFF Research Database (Denmark)

    Hauge, Anne Werner; Hougaard, Anders; Olesen, Jes

    2010-01-01

    INTRODUCTION: Specific problems occur in clinical treatment trials for migraine with aura that differ from those encountered in treatment trials for migraine without aura. DISCUSSION: Based on our experience with four such trials, we point to a number of possible solutions and outline areas...... for future inquiry. We make recommendations about subject selection; the choice, definition and assessment of outcome measures; optimal treatments in relation to aura and headache; and we provide samples of study report forms used to record occurrence of aura and headache in this population....

  16. Biogenic methanol and its impacts on tropospheric oxidants

    Science.gov (United States)

    Tie, Xuexi; Guenther, Alex; Holland, Elisabeth

    2003-09-01

    We use a global chemical transport model (MOZART-2) to estimate the effects of surface emissions of methanol on tropospheric oxidants. The importance of methanol in tropospheric chemistry is two fold. First, methanol has a relatively large surface emission with an estimated global emission of 70 to 350 Tg methanol/year. The estimated methanol flux is comparable to other major hydrocarbon surface emissions such as isoprene and total monoterpenes, but the chemical lifetime of methanol is several days (in the boundary layer) to a few weeks (in the upper troposphere), which is much longer than the chemical lifetime of isoprene or monoterpenes (For example, the chemical lifetime of isoprene is about 2 hours). With a surface emission of 104 to 312 Tg methanol/year (encompasses estimated uncertainty in methanol emissions), the calculation shows that on average, the inclusion of methanol emission produces approximately 1-2% increase in O3, 1-3% decrease in OH, 3-5% increase in HO2, and 3-9% increase in CH2O globally. The maximum perturbation to the oxidants occurs in the tropical upper troposphere. However, the uncertainty associated with current methanol emission estimates produces significantly different model predictions of tropospheric oxidant distributions.

  17. Tropospheric Composition Change observed from Space (Invited)

    Science.gov (United States)

    Richter, A.; Hilboll, A.; Leitao, J.; Vrekoussis, M.; Wittrock, F.; Burrows, J. P.

    2010-12-01

    The composition of the troposphere is largely influenced by surface emissions of both natural and anthropogenic origins. These emissions change over time as result of human activities and natural variability, leading to varying atmospheric levels of primary and secondary pollutants. Satellite observations of sun light scattered back by the surface and the atmosphere can be used to retrieve information on atmospheric trace gases by application of optical absorption spectroscopy. In the UV and visible part of the spectrum, these measurements have good sensitivity to the lower troposphere providing information on relevant species such as O3, NO2, SO2, HCHO or glyoxal. Here, we report on recent results on tropospheric composition changes obtained from the GOME, SCIAMACHY and GOME-2 instruments which have a combined data record of nearly 15 years. The focus is on NO2 which shows an increasing trend over Asia and many large cities in countries with growing economies. At the same time, significant reductions are observed over the US and Europe, probably as result of changes in environmental legislation. SO2 signals have been decreasing over the US since 1996 while a strong upward trend was evident over China until recently when desulphurisation of power plant emissions came into effect. There also is evidence for increases in VOC levels over China which could be either of anthropogenic origin or from biogenic emissions.

  18. On the methodology of drug trials in migraine with aura

    DEFF Research Database (Denmark)

    Hauge, Anne Werner; Hougaard, Anders; Olesen, Jes

    2010-01-01

    INTRODUCTION: Specific problems occur in clinical treatment trials for migraine with aura that differ from those encountered in treatment trials for migraine without aura. DISCUSSION: Based on our experience with four such trials, we point to a number of possible solutions and outline areas...

  19. De Ligeia a Aura: una distancia salvable

    OpenAIRE

    Mendoza Z., Mario

    2004-01-01

    Partiendo del análisis literario como una gran aventura donde el crítico intenta ahondar en los secretos que esconden las páginas de los libros, hemos buscado a lo largo de este trabajo establecer algunos marcos de referencia dentro de los cuales puedan comprenderse los relatos Ligeia, de Edgar Alan Poe, y Aura, de Carlos Fuentes, sin obviar por ello otras posibles lectu­ras que se han llevado a cabo, y que sin duda son la prueba más sólida de la riqueza literaria de estos textos.  

  20. Two Patients With Visual Aura - Migraine, Epilepsy, or Migralepsy?

    Science.gov (United States)

    Hartl, Elisabeth; Rémi, Jan; Noachtar, Soheyl

    2015-09-01

    The concept of migralepsy refers to visual migraine auras that seemingly evolve into epileptic seizures. It was discussed controversially ever since and scientific proof for this entity is scarce. We report two patients with visual aura fulfilling the diagnostic criteria for migralepsy. In both patients, habitual attacks were recorded during long-term video electroencephalography (EEG) monitoring. Both patients demonstrated unilateral occipital EEG seizure patterns during their long-lasting visual aura, which eventually evolved into versive seizures. Here, we prove the epileptic origin of the visual auras, which have been misdiagnosed as migraine or migralepsy before. Additional evaluation should be considered in patients with visual aura and hints for an epileptic origin as occipital lobe epilepsy might be missed in patients diagnosed with migraine. Based on our patients, we suggest to challenge the concept of migralepsy in current classifications. © 2015 American Headache Society.

  1. Visual evoked potentials in subgroups of migraine with aura patients.

    Science.gov (United States)

    Coppola, Gianluca; Bracaglia, Martina; Di Lenola, Davide; Di Lorenzo, Cherubino; Serrao, Mariano; Parisi, Vincenzo; Di Renzo, Antonio; Martelli, Francesco; Fadda, Antonello; Schoenen, Jean; Pierelli, Francesco

    2015-01-01

    Patients suffering from migraine with aura can have either pure visual auras or complex auras with sensory disturbances and dysphasia, or both. Few studies have searched for possible pathophysiological differences between these two subgroups of patients. Methods - Forty-seven migraine with aura patients were subdivided in a subgroup with exclusively visual auras (MA, N = 27) and another with complex neurological auras (MA+, N = 20). We recorded pattern-reversal visual evoked potentials (VEP: 15 min of arc cheques, 3.1 reversal per second, 600 sweeps) and measured amplitude and habituation (slope of the linear regression line of amplitude changes from the 1st to 6th block of 100 sweeps) for the N1-P1 and P1-N2 components in patients and, for comparison, in 30 healthy volunteers (HV) of similar age and gender distribution. VEP N1-P1 habituation, i.e. amplitude decrement between 1st and 6th block, which was obvious in most HV (mean slope -0.50), was deficient in both MA (slope +0.01, p = 0.0001) and MA+ (-0.0049, p = 0.001) patients. However, VEP N1-P1 amplitudes across blocks were normal in MA patients, while they were significantly greater in MA+ patients than in HVs. Our findings suggest that in migraine with aura patients different aura phenotypes may be underpinned by different pathophysiological mechanisms. Pre-activation cortical excitability could be higher in patients with complex neurological auras than in those having pure visual auras or in healthy volunteers.

  2. Observations of primary and secondary emissions in a B747 exhaust plume in the upper troposphere and inferred engine exit plane OH concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Schlager, H.; Schulte, P.; Tremmel, H.G.; Ziereis, H. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Wessling (Germany). Inst. fuer Physik der Atmosphaere; Arnold, F.; Droste-Franke, B.; Klemm, M.; Schneider, J. [Max-Planck-Inst. fuer Kernphysik, Heidelberg (Germany)

    1997-12-31

    The speciation of NO{sub y} exhaust emissions in the near-field plume of a B747 cruising at 9.2 km was measured in situ using the DLR Falcon research aircraft instrumented with a chemical ionisation mass spectrometer of MPI-K and a chemiluminescence NO detector of DLR. In addition, CO{sub 2} was measured providing a dilution factor for the exhaust species. Observed maximum peak concentrations above background in the plume 60 s after emission were 25.4 ppmv (CO{sub 2}), 184 ppbv (NO), 2.6 ppbv (HNO{sub 2}), and 1.3 ppbv (HNO{sub 3}). The observations were used to infer the initial OH concentration (15.4 ppmv) and NO{sub 2}/NO{sub x} ratio (0.08) at the engine exit by back calculations using a chemistry box model. (author) 20 refs.

  3. The tropospheric monitoring instrument

    NARCIS (Netherlands)

    Voert, M.J. te; Brakel, R. van; Witvoet, G.

    2014-01-01

    Thermal and opto-mechanical design and analysis work has been done on the Tropospheric Monitoring Instrument (TROPOMI), a spectrometer on the Copernicus Sentinel 5 Precursor satellite. To verify compliance with the stringent opto-mechanical stability requirements, detailed thermal and thermo-mechani

  4. Linkages between ozone depleting substances, tropospheric oxidation and aerosols

    Directory of Open Access Journals (Sweden)

    A. Voulgarakis

    2012-09-01

    Full Text Available Coupling between the stratosphere and the troposphere allows changes in stratospheric ozone abundances to affect tropospheric chemistry. Large-scale effects from such changes on chemically produced tropospheric aerosols have not been systematically examined in past studies. We use a composition-climate model to investigate potential past and future impacts of changes in stratospheric Ozone Depleting Substances (ODS on tropospheric oxidants and sulfate aerosols. In most experiments, we find significant responses in tropospheric photolysis and oxidants, with small but significant effects on methane radiative forcing. The response of sulfate aerosols is sizeable when examining the effect of increasing future nitrous oxide (N2O emissions. We also find that without the regulation of chlorofluorocarbons (CFCs through the Montreal Protocol, sulfate aerosols could have increased by 2050 by a comparable amount to the decreases predicted due to relatively stringent sulfur emissions controls. The historical radiative forcing of CFCs through their indirect effects on methane (−22.6 mW m−2 and sulfate aerosols (−3.0 mW m−2 discussed here is non-negligible when compared to known historical CFC forcing. Our results stress the importance of accounting for stratosphere-troposphere, gas-aerosol and composition-climate interactions when investigating the effects of changing emissions on atmospheric composition and climate.

  5. Pure menstrual migraine with sensory aura: a case report.

    Science.gov (United States)

    Chen, Jiann-Jy; Hsu, Yung-Chu; Chen, Dem-Lion

    2012-07-01

    Hormonal changes related to the menstrual cycle have a great impact on migraines in women. Menstrual migraine attacks are almost invariably without aura. Categorizing migraines into menstrual or non-menstrual types is one way to stratify migraines without aura according to the appendix criteria of the International Classification of Headache Disorders. We report a peri-menopausal woman whose sensory aura exclusively heralded menstrual migraine. A 51-year-old woman had suffered from monthly episodic headaches since the age of 46. Before a headache, and within 1 h on the first day of her menstruation, she always experienced numbness in her entire left upper limb. After the sensory aura, migrainous headaches occurred with nausea and photophobia. In the postmenopausal period, she no longer had sensory aura, and her headache pattern changed and became less severe. Her physical and neurologic exams as well as electroencephalography, brain magnetic resonance imaging, and conventional angiography were all normal. She fulfilled the diagnosis of pure menstrual migraine with typical sensory aura. To our knowledge, this is the first formal case report of pure menstrual migraine with aura.

  6. A-Train Observations of Stratosphere-Troposphere Exchange During 2006

    Science.gov (United States)

    Wicks, D. E.; McMillan, W. W.; Osterman, G.; Livesey, N.; Browell, E.; Irion, F. W.

    2007-12-01

    Studies of jet stream and frontal boundary dynamics with atmospheric tracer measurements provide insight to the coupled stratosphere-troposphere system. A-Train satellite instruments possess the horizontal and vertical resolution along with temporal and spatial coincidence necessary to identify stratospheric intrusions, investigate their three-dimensional structure, and estimate cross-tropopause exchange. We present results from our analysis of tropospheric chemistry and dynamics using AIRS and Aura instruments to observe stratospheric intrusions along the polar jet during the 2006 Intercontinental Chemical Transport Experiment Phase B (INTEX-B) field experiment. Focusing on April-May 2006, we explore the temporal and spatial evolution of STE events over the Pacific Ocean originating off the eastern coast of China and traveling along the storm track to the North American west coast. With the broad swath of AIRS and the higher vertical resolution of Aura instruments like TES, ozone and water vapor retrievals show typical features of stratosphere-troposphere exchange in the UTLS near dominant meteorological structures. Analyses of in-situ and aircraft remote sensing measurements of these trace gases compare well with the satellite observations.

  7. Troposphere-stratosphere exchange - constraints from water vapour

    Science.gov (United States)

    Liu, Y.; Du, J.; Fueglistaler, S.; Haynes, P. H.

    2008-12-01

    Transport into the stratospheric 'overworld' is thought to occur predominantly across the tropical tropopause, whereas transport into the lowermost stratosphere may also occur through quasi-horizontal transport on isentropic levels between 300 and 380K potential temperature. The distribution of stratospheric water vapour is sensitively dependent upon the detailed temperature history of air parcel trajectories, and combined with a Lagrangian study can be used as a tracer for quantifying the relative importance of cross-isentropic mass flux and quasi-isentropic mass flux into the stratosphere. Here we combine measurements from the Microwave Limb Sounder on board of AURA satellite, with trajectory calculations to diagnose the pathways of troposphere-stratosphere exchange. Trajectories are calculated using winds and diabatic heating rates from the new interim reanalysis currently carried out at the European Centre for Medium-range Weather Forecast.

  8. AURA - A radio frequency extension to IceCube

    CERN Document Server

    Ruckman, L

    2008-01-01

    The excellent radio frequency transparency of cold polar ice, combined with the coherent Cherenkov emission produced by neutrino-induced showers when viewed at wavelengths longer than a few centimeters, has spurred considerable interest in a large-scale radio-wave neutrino detector array. The AURA (Askaryan Under-ice Radio Array) experimental effort, within the IceCube collaboration, seeks to take advantage of the opportunity presented by IceCube drilling through 2010 to establish the radio frequency technology needed to achieve 100-1000 km^3 effective volumes. In the 2006-2007 Austral summer 3 deep in-ice radio frequency (RF) clusters were deployed at depths of 1300m and 300m on top of the IceCube strings. Additional 3 clusters will be deployed in the Austral summer of 2008-2009. Verification and calibration results from the current deployed clusters are presented, and the detector design and performances are discussed. Augmentation of IceCube with large-scale 1000km^3sr radio and acoustic arrays would exten...

  9. Global tropospheric hydroxyl distribution, budget and reactivity

    Science.gov (United States)

    Lelieveld, Jos; Gromov, Sergey; Pozzer, Andrea; Taraborrelli, Domenico

    2016-10-01

    The self-cleaning or oxidation capacity of the atmosphere is principally controlled by hydroxyl (OH) radicals in the troposphere. Hydroxyl has primary (P) and secondary (S) sources, the former mainly through the photodissociation of ozone, the latter through OH recycling in radical reaction chains. We used the recent Mainz Organics Mechanism (MOM) to advance volatile organic carbon (VOC) chemistry in the general circulation model EMAC (ECHAM/MESSy Atmospheric Chemistry) and show that S is larger than previously assumed. By including emissions of a large number of primary VOC, and accounting for their complete breakdown and intermediate products, MOM is mass-conserving and calculates substantially higher OH reactivity from VOC oxidation compared to predecessor models. Whereas previously P and S were found to be of similar magnitude, the present work indicates that S may be twice as large, mostly due to OH recycling in the free troposphere. Further, we find that nighttime OH formation may be significant in the polluted subtropical boundary layer in summer. With a mean OH recycling probability of about 67 %, global OH is buffered and not sensitive to perturbations by natural or anthropogenic emission changes. Complementary primary and secondary OH formation mechanisms in pristine and polluted environments in the continental and marine troposphere, connected through long-range transport of O3, can maintain stable global OH levels.

  10. Epileptic aura and perception of self-control

    DEFF Research Database (Denmark)

    Lohse, Allan; Kjaer, Troels W; Sabers, Anne

    2015-01-01

    of others (e.g., doctors and parents). The Hospital Anxiety and Depression Scale was used to evaluate levels of anxiety and depression. RESULTS: Forty-nine patients, with mean age of 38years, participated in the study. Of these, 67% reported experiencing one or more auras; i.e., subjective warning signs...... prior to a generalized or focal seizure with an impairment in consciousness. Patients that could react to their aura prior to a seizure scored higher on the internal subscale of the Multidimensional Health Locus of Control questionnaire compared to participants that could not react to their aura......, there was no significant relation between the ability to react to an aura prior to a seizure and the levels of anxiety or depression....

  11. Auditory aura in frontal opercular epilepsy: sounds from afar.

    Science.gov (United States)

    Thompson, Stephen A; Alexopoulos, Andreas; Bingaman, William; Gonzalez-Martinez, Jorge; Bulacio, Juan; Nair, Dileep; So, Norman K

    2015-06-01

    Auditory auras are typically considered to localize to the temporal neocortex. Herein, we present two cases of frontal operculum/perisylvian epilepsy with auditory auras. Following a non-invasive evaluation, including ictal SPECT and magnetoencephalography, implicating the frontal operculum, these cases were evaluated with invasive monitoring, using stereoelectroencephalography and subdural (plus depth) electrodes, respectively. Spontaneous and electrically-induced seizures showed an ictal onset involving the frontal operculum in both cases. A typical auditory aura was triggered by stimulation of the frontal operculum in one. Resection of the frontal operculum and subjacent insula rendered one case seizure- (and aura-) free. From a hodological (network) perspective, we discuss these findings with consideration of the perisylvian and insular network(s) interconnecting the frontal and temporal lobes, and revisit the non-invasive data, specifically that of ictal SPECT.

  12. Aqua/Aura Spring 2017 Inclination Adjust Maneuver Series

    Science.gov (United States)

    Noyes, Thomas; Stezelberger, Shane

    2017-01-01

    This will be presented at the International Earth Science Constellation Mission Operations Working Group meeting June 13-15, 2017 to discuss the AquaAura Spring 2017 Inclination Adjust Maneuver series.

  13. Variability of clinical features in attacks of migraine with aura

    DEFF Research Database (Denmark)

    Hansen, Jakob M; Goadsby, Peter J; Charles, Andrew C

    2016-01-01

    BACKGROUND: There is significant variability in the clinical presentation of migraine, both among patients, and between attacks in an individual patient. We examined clinical features of migraine with aura in a large group of patients enrolled in a clinical trial, and compared retrospective...... migraine attack characteristics reported upon enrollment in the trial with those recorded prospectively in the trial. METHODS: Patients with migraine (n = 267) with typical visual aura in more than 30% of their attacks were enrolled from 16 centers for a clinical trial. Upon enrollment, patients provided...... a detailed retrospective description of the clinical features of their attacks of migraine. During the trial, clinical symptoms in migraine attacks starting with aura were recorded prospectively in 861 attacks. RESULTS: Retrospectively reported visual aura symptoms were variable and often overlapping...

  14. Relation of Trigger Factors to Migraine with Aura

    Directory of Open Access Journals (Sweden)

    J. Gordon Millichap

    2013-03-01

    Full Text Available Researchers from the University of Copenhagen, Denmark studied the relation between natural trigger factors and migraine with aura (MA in 27 patients who reported that bright or flickering light or strenuous exercise would trigger their attacks.

  15. Halogen chemistry reduces tropospheric O3 radiative forcing

    Science.gov (United States)

    Sherwen, Tomás; Evans, Mat J.; Carpenter, Lucy J.; Schmidt, Johan A.; Mickley, Loretta J.

    2017-01-01

    Tropospheric ozone (O3) is a global warming gas, but the lack of a firm observational record since the preindustrial period means that estimates of its radiative forcing (RFTO3) rely on model calculations. Recent observational evidence shows that halogens are pervasive in the troposphere and need to be represented in chemistry-transport models for an accurate simulation of present-day O3. Using the GEOS-Chem model we show that tropospheric halogen chemistry is likely more active in the present day than in the preindustrial. This is due to increased oceanic iodine emissions driven by increased surface O3, higher anthropogenic emissions of bromo-carbons, and an increased flux of bromine from the stratosphere. We calculate preindustrial to present-day increases in the tropospheric O3 burden of 113 Tg without halogens but only 90 Tg with, leading to a reduction in RFTO3 from 0.43 to 0.35 Wm-2. We attribute ˜ 50 % of this reduction to increased bromine flux from the stratosphere, ˜ 35 % to the ocean-atmosphere iodine feedback, and ˜ 15 % to increased tropospheric sources of anthropogenic halogens. This reduction of tropospheric O3 radiative forcing due to halogens (0.087 Wm-2) is greater than that from the radiative forcing of stratospheric O3 (˜ 0.05 Wm-2). Estimates of RFTO3 that fail to consider halogen chemistry are likely overestimates (˜ 25 %).

  16. Photochemical oxidation of halocarbons in the troposphere

    Energy Technology Data Exchange (ETDEWEB)

    Cox, R.A. (Atomic Energy Research Establishment, Harwell, Eng.); Derwent, R.G.; Eggleton, A.E.J.; Lovelock, J.E.

    1976-01-01

    Measurements of the reactivity of hydroxyl radicals with some simple halocarbons are reported, together with some new measurements of the air concentration of halocarbons in the N and S hemispheres. The OH reactivities are used to derive life-times of the halocarbons with respect to photo-oxidation in the troposphere. It is found that the chlorohydrocarbons containing H atoms are moderately reactive with lifetimes of 1 y or less but the fully halogenated compounds carbon tetrachloride and Freons 11 and 12 are essentially inert towards photo-oxidation. The air concentration and reactivity data are combined to provide an estimate of the magnitude of the tropospheric sink for the halocarbons due to oxidation by OH radicals. For some of the more reactive halocarbons this sink exceeds the estimated anthropogenic emissions and an additional, possibly natural, source is indicated.

  17. Migraine with aura and patent foramen ovale: myth or reality?

    Science.gov (United States)

    Finocchi, C; Del Sette, M

    2015-05-01

    Several observational studies report that subjects with migraine with aura have a higher prevalence of right-to left shunt, commonly due to patent foramen ovale, and that patent foramen ovale is more prevalent in subjects with migraine with aura. Although migraine without aura has been less extensively studied, it does not seem to be associated with an increased prevalence of right-to left shunt. The mechanism that underlies the possible relationship between patent foramen ovale and migraine with aura remains speculative. The proposed mechanisms are migraine-triggering vasoactive chemicals bypassing the pulmonary filter and reaching the cerebral circulation and paradoxical microembolization. However, it is unclear, at this time, if there is a causal or comorbid association between the two conditions. In some families atrial shunts show a dominant inheritance that seems to be linked to inheritance of migraine with aura. Migraine with aura is an independent risk factor for ischemic stroke, and patent foramen ovale is present more frequently in patients with cryptogenic stroke than in controls. At this moment, there is no convincing evidence that excess stroke risk of migraine is simply mediated by patent foramen ovale through paradoxical embolism. Several non-controlled studies suggest that closure of the foramen ovale significantly reduces attack frequency in migraine patient, but the only prospective placebo-controlled trial does not support these results. Patent foramen ovale closure, at present, is not indicated as a treatment for migraine in clinical practice.

  18. Pediatric migraine with aura in an Italian case series.

    Science.gov (United States)

    Taga, Arens; Russo, Marco; Genovese, Antonio; Paglia, Maria Vittoria; Manzoni, Gian Camillo; Torelli, Paola

    2017-05-01

    The aim of the present study was to describe the characteristics of migraine with aura (MwA) in a case series of patients with headache onset before 12 years of age. We considered all consecutive patients referred to the Parma Headache Centre between 1975 and 2015 affected by MwA, diagnosed by our team of trained neurologists; the cases were subsequently reviewed applying the ICHD3-beta criteria. We then identified those cases with headache age-of-onset aura was the most common type of aura, followed by sensory and speech disturbances; however, these two latter aura symptoms were significantly more common among pediatric cases. In this group of patients, aura without headache was significantly less frequent (1.8 vs 5.3%); furthermore, headache had migraine characteristics in a higher proportion of cases (90.1 vs 82.6%). A family history of MwA was significantly more frequent among cases with pediatric onset (31.1 vs 16.9%). Males but not females with pediatric MwA had more frequently a comorbid migraine without aura (27.6 vs 16.8%). Among cases with pediatric onset, we did not find any significant differences between males and females. In conclusion, in our very large case series of MwA, patients with headache onset before 12 years of age seem to have a specific clinical phenotype, without significant gender differences.

  19. Maintaining Aura's Orbit Requirements Under New Maneuver Operations

    Science.gov (United States)

    Johnson, Megan; Petersen, Jeremy D.

    2014-01-01

    The Earth Observing System (EOS) Afternoon Constellation consists of five member missions (GCOM-W1, Aqua, CALIPSO, CloudSat, and Aura), each of which maintain a frozen, sun-synchronous orbit with a 16-day repeating ground track that follows the Worldwide Reference System-2 (WRS-2). Under nominal science operations for Aura, the propulsion system is oriented such that the resultant thrust vector is aligned 13.493 degrees away from the velocity vector along the yaw axis. When performing orbit maintenance maneuvers, the spacecraft performs a yaw slew to align the thrust vector in the appropriate direction. A new Drag Make Up (DMU) maneuver operations scheme has been implemented for Aura alleviating the need for the 13.493 degree yaw slew. The focus of this investigation is to assess the impact that no-slew DMU maneuver operations will have on Auras Mean Local Time (MLT) which drives the required along track separation between Aura and the constellation members, as well as Auras frozen orbit properties, eccentricity and argument of perigee. Seven maneuver strategies were analyzed to determine the best operational approach. A mirror pole strategy, with maneuvers alternating at the North and South poles, was implemented operationally to minimize impact to the MLT. Additional analysis determined that the mirror pole strategy could be further modified to include frozen orbit maneuvers and thus maintain both MLT and the frozen orbit properties under no-slew operations

  20. Epilepsia do lobo temporal com aura de prazer: relato de caso Temporal lobe epilepsy with aura of pleasure: case report

    OpenAIRE

    2000-01-01

    Relatamos o caso de uma paciente com epilepsia do lobo temporal e "sensação de orgasmo" como aura epiléptica. Há controvérsia na literatura a respeito da existência do prazer e do êxtase como manifestação de aura epiléptica. Neste caso, ficou evidenciada a presença da aura de prazer, através da investigação clínica, eletrencefalograma e remissão das crises com a terapêutica adotada (fenitoína).We report on a woman with temporal lobe epilepsy and "orgasm sensation" like an epileptic aura. Lite...

  1. A multi-model intercomparison of halogenated very short-lived substances (TransCom-VSLS): linking oceanic emissions and tropospheric transport for a reconciled estimate of the stratospheric source gas injection of bromine

    Science.gov (United States)

    Hossaini, R.; Patra, P. K.; Leeson, A. A.; Krysztofiak, G.; Abraham, N. L.; Andrews, S. J.; Archibald, A. T.; Aschmann, J.; Atlas, E. L.; Belikov, D. A.; Bönisch, H.; Carpenter, L. J.; Dhomse, S.; Dorf, M.; Engel, A.; Feng, W.; Fuhlbrügge, S.; Griffiths, P. T.; Harris, N. R. P.; Hommel, R.; Keber, T.; Krüger, K.; Lennartz, S. T.; Maksyutov, S.; Mantle, H.; Mills, G. P.; Miller, B.; Montzka, S. A.; Moore, F.; Navarro, M. A.; Oram, D. E.; Pfeilsticker, K.; Pyle, J. A.; Quack, B.; Robinson, A. D.; Saikawa, E.; Saiz-Lopez, A.; Sala, S.; Sinnhuber, B.-M.; Taguchi, S.; Tegtmeier, S.; Lidster, R. T.; Wilson, C.; Ziska, F.

    2016-07-01

    The first concerted multi-model intercomparison of halogenated very short-lived substances (VSLS) has been performed, within the framework of the ongoing Atmospheric Tracer Transport Model Intercomparison Project (TransCom). Eleven global models or model variants participated (nine chemical transport models and two chemistry-climate models) by simulating the major natural bromine VSLS, bromoform (CHBr3) and dibromomethane (CH2Br2), over a 20-year period (1993-2012). Except for three model simulations, all others were driven offline by (or nudged to) reanalysed meteorology. The overarching goal of TransCom-VSLS was to provide a reconciled model estimate of the stratospheric source gas injection (SGI) of bromine from these gases, to constrain the current measurement-derived range, and to investigate inter-model differences due to emissions and transport processes. Models ran with standardised idealised chemistry, to isolate differences due to transport, and we investigated the sensitivity of results to a range of VSLS emission inventories. Models were tested in their ability to reproduce the observed seasonal and spatial distribution of VSLS at the surface, using measurements from NOAA's long-term global monitoring network, and in the tropical troposphere, using recent aircraft measurements - including high-altitude observations from the NASA Global Hawk platform. The models generally capture the observed seasonal cycle of surface CHBr3 and CH2Br2 well, with a strong model-measurement correlation (r ≥ 0.7) at most sites. In a given model, the absolute model-measurement agreement at the surface is highly sensitive to the choice of emissions. Large inter-model differences are apparent when using the same emission inventory, highlighting the challenges faced in evaluating such inventories at the global scale. Across the ensemble, most consistency is found within the tropics where most of the models (8 out of 11) achieve best agreement to surface CHBr3 observations

  2. Aura neo&Aura Groove 新音乐时代的优雅小清新

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    如果你认为只要一提到Hi-Fi便逃离不了傻、大、粗、笨、丑等传统字眼的话那么当你看到Aura neo CD播放器与Aura Groove合并功放时,你必然会被他们的小清新风格所打动。

  3. Validation of the Aura Microwave Limb Sounder Temperature and Geopotential Height Measurements

    Science.gov (United States)

    Schwartz, M. J.; Lambert, A.; Manney, G. L.; Read, W. G.; Livesey, N. J.; Froidevaux, L.; Ao, C. O.; Bernath, P. F.; Boone, C. D.; Cofield, R. E.; Daffer, W. H.; Drouin, B. J.; Fetzer, E. J.; Fuller, R. A.; Jarnot, R. F.; Jiang, J. H.; Jiang, Y. B.; Knosp, B. W.; Krueger, K.; Li, J.-L. F.; Mlynczak, M. G.; Pawson, S.; Russell, J. M., III; Santee, M. L.; Snyder, W. V.

    2007-01-01

    This paper describes the retrievals algorithm used to determine temperature and height from radiance measurements by the Microwave Limb Sounder on EOS Aura. MLS is a "limbscanning" instrument, meaning that it views the atmosphere along paths that do not intersect the surface - it actually looks forwards from the Aura satellite. This means that the temperature retrievals are for a "profile" of the atmosphere somewhat ahead of the satellite. Because of the need to view a finite sample of the atmosphere, the sample spans a box about 1.5km deep and several tens of kilometers in width; the optical characteristics of the atmosphere mean that the sample is representative of a tube about 200-300km long in the direction of view. The retrievals use temperature analyses from NASA's Goddard Earth Observing System, Version 5 (GEOS-5) data assimilation system as a priori states. The temperature retrievals are somewhat deperrdezt on these a priori states, especially in the lower stratosphere. An important part of the validation of any new dataset involves comparison with other, independent datasets. A large part of this study is concerned with such comparisons, using a number of independent space-based measurements obtained using different techniques, and with meteorological analyses. The MLS temperature data are shown to have biases that vary with height, but also depend on the validation dataset. MLS data are apparently biased slightly cold relative to correlative data in the upper troposphere and slightly warm in the middle stratosphere. A warm MLS bias in the upper stratosphere may be due to a cold bias in GEOS-5 temperatures.

  4. Epileptic aura and perception of self-control.

    Science.gov (United States)

    Lohse, Allan; Kjaer, Troels W; Sabers, Anne; Wolf, Peter

    2015-04-01

    The health locus of control is the subjective perception of control over one's health. It has been studied for years as one of several factors that determine patient health-related behaviors. The aim of this study was to investigate how the epileptic aura is associated with the health locus of control, anxiety, and depression. Patients were included retrospectively, based on patient records from the epilepsy monitoring unit of the Rigshospitalet University Hospital. Participants were asked about the presence and nature of auras in a semistructured interview. The Multidimensional Health Locus of Control Scale, Form C was used to evaluate the health locus of control. Three domains were evaluated: internal, where health is controlled by personal action; chance, where health is controlled by fate or luck; and powerful others, where health is controlled by the actions of others (e.g., doctors and parents). The Hospital Anxiety and Depression Scale was used to evaluate levels of anxiety and depression. Forty-nine patients, with mean age of 38years, participated in the study. Of these, 67% reported experiencing one or more auras; i.e., subjective warning signs prior to a generalized or focal seizure with an impairment in consciousness. Patients that could react to their aura prior to a seizure scored higher on the internal subscale of the Multidimensional Health Locus of Control questionnaire compared to participants that could not react to their aura. The ability to react to an aura prior to a seizure correlated positively with the internal subscale of the health locus of control. However, it did not significantly correlate with the external subscales of chance and powerful others in the health locus of control. Moreover, there was no significant relation between the ability to react to an aura prior to a seizure and the levels of anxiety or depression. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Tropospheric Ozone and Photochemical Smog

    Science.gov (United States)

    Sillman, S.

    2003-12-01

    global background ozone can make the effects of local pollution events everywhere more acute, and can also cause ecological damage in remote locations that are otherwise unaffected by urban pollution. Ozone at the global scale is also related to greenhouse warming.This chapter provides an overview of photochemical smog at the urban and regional scale, focused primarily on ozone and including a summary of information about particulates. It includes the following topics: dynamics and extent of pollution events; health and ecological impacts; relation between ozone and precursor emissions, including hydrocarbons and nitrogen oxides (NOx); sources, composition, and fundamental properties of particulates; chemistry of ozone and related species; methods of interpretation based on ambient measurements; and the connection between air pollution events and the chemistry of the global troposphere. Because there are many similarities between the photochemistry of ozone during pollution events and the chemistry of the troposphere in general, this chapter will include some information about global tropospheric chemistry and the links between urban-scale and global-scale events. Additional treatment of the global troposphere is found in Volume 4 of this work. The chemistry of ozone formation discussed here is also related to topics discussed in greater detail elsewhere in this volume (see Chapters 9.10 and 9.12) and in Volume 4.

  6. Upper tropospheric ice sensitivity to sulfate geoengineering

    Science.gov (United States)

    Visioni, Daniele; Pitari, Giovanni; Mancini, Eva

    2017-04-01

    In light of the Paris Agreement which aims to keep global warming under 2 °C in the next century and considering the emission scenarios produced by the IPCC for the same time span, it is likely that to remain below that threshold some kind of geoengineering technique will have to be deployed. Amongst the different methods, the injection of sulfur into the stratosphere has received much attention considering its effectiveness and affordability. Aside from the rather well established surface cooling sulfate geoengineering (SG) would produce, the investigation on possible side-effects of this method is still ongoing. For instance, some recent studies have investigated the effect SG would have on upper tropospheric cirrus clouds, expecially on the homogenous freezing mechanisms that produces the ice particles (Kuebbeler et al., 2012). The goal of the present study is to better understand the effect of thermal and dynamical anomalies caused by SG on the formation of ice crystals via homogeneous freezing by comparing a complete SG simulation with a RCP4.5 reference case and with a number of sensitivity studies where atmospheric temperature changes in the upper tropospheric region are specified in a schematic way as a function of the aerosol driven stratospheric warming and mid-lower tropospheric cooling. These changes in the temperature profile tend to increase atmospheric stabilization, thus decreasing updraft and with it the amount of water vapor available for homogeneous freezing in the upper troposphere. However, what still needs to be assessed is the interaction between this dynamical effect and the thermal effects of tropospheric cooling (which would increase ice nucleation rates) and stratospheric warming (which would probably extend to the uppermost troposphere via SG aerosol gravitational settling, thus reducing ice nucleation rates), in order to understand how they combine together. Changes in ice clouds coverage could be important for SG, because cirrus ice

  7. The visual aura rating scale as an outcome predictor for persistent visual aura without infarction.

    Science.gov (United States)

    Wang, Y-F; Fuh, J-L; Chen, W-T; Wang, S-J

    2008-12-01

    Persistent visual aura without infarction is rare. Its pathogenic mechanism is unknown, and the response to migraine prophylactic agents varies. A systematic analysis of 29 patients (23 from the literature and six in the present report; 6M/23F, mean age 37.6 years) was carried out in terms of demographics, headache and visual symptom profiles, treatment regimens and outcomes. Patterns of visual disturbances (VDs) were re-assessed with the Visual Aura Rating Scale (VARS, score 0-10). Even though the majority of patients had headache improvement, only eight (27.6%) had complete resolution of persistent VD, without definite relevance to any specific agent. Patients with complete resolution of VD tended to have scotoma (50.0% vs. 0%; P = 0.003), unilateral/homonymous involvement (62.5% vs. 9.5%; P = 0.008), higher VARS scores (1.88 +/- 1.73 vs. 0.10 +/- 0.30; P outcome. For those with a potential for complete resolution, improvement would occur early in the course.

  8. Constraints on Asian ozone using Aura TES, OMI and Terra MOPITT

    Directory of Open Access Journals (Sweden)

    Z. Jiang

    2014-07-01

    Full Text Available Rapid industrialization in Asia in the last two decades has resulted in a significant increase in Asian ozone (O3 pre-cursor emissions with likely a corresponding increase in the export of O3 and its pre-cursors. However, the relationship between this increasing O3, the chemical environment, O3 production efficiency, and the partitioning between anthropogenic and natural precursors is unclear. In this work, we use satellite measurements of O3, CO and NO2 from TES (Tropospheric Emission Spectrometer, MOPITT (Measurement of Pollution In The Troposphere and OMI (Ozone Monitoring Instrument to quantify O3 pre-cursor emissions for 2006 and their impact on free-tropospheric O3 over North-East Asia, where pollution is typically exported globally due to strong westerlies. Using the GEOS-Chem global chemical transport model, we show that the modeled seasonal variation of O3 based on these updated O3 pre-cursor emissions is consistent with the observed O3 variability and amount, after accounting for known biases in the TES O3 data. Using the adjoint of GEOS-Chem we then partition the relative contributions of natural and anthropogenic sources to free troposphere O3 in this region. We find that the influence of lightning NOx is important in summer. The contribution from anthropogenic NOx is dominant in other seasons. China is the major contributor of anthropogenic VOCs (Volatile Organic Compounds, whereas the influence of biogenic VOCs is mainly from Southeast Asia. Our result shows that the influence of India and Southeast Asia emissions on O3 pollution export is significant, comparable with Chinese emisisons in winter and about 50% of Chinese emissions in other seasons.

  9. Migraine aura lasting 1-24 h in children: a sequence of EEG slow-wave abnormalities vs. vascular events.

    Science.gov (United States)

    Parain, D; Hitzel, A; Guegan-Massardier, E; Lebas, A; Blondeau, C; Fédina, I; Feray, D; Véra, P; Mihout, B

    2007-09-01

    The aim of this study was to describe the abnormalities associated with migraine aura lasting 1-24 h in children as shown by EEG, trancranial Doppler (TCD) and single photon emission computed tomography (SPECT). In this retrospective study, 11 patients each underwent EEG, TCD and brain SPECT on the day of admission and the day thereafter. On the day of admission, the migrainous hemisphere of all patients showed that the mean velocities were decreased in the middle cerebral artery by TCD, slow-wave abnormalities were recorded after several hours of aura by EEG and the SPECT showed hypoperfusion. On the day after, in the same hemisphere, slow waves were recorded only in the occipital area by EEG, and SPECT showed slight hyperperfusion. In these patients, there was a clear sequence of EEG, TCD and SPECT abnormalities.

  10. Hydrological controls on the tropospheric ozone greenhouse gas effect

    Directory of Open Access Journals (Sweden)

    Le Kuai

    2017-03-01

    Full Text Available The influence of the hydrological cycle in the greenhouse gas (GHG effect of tropospheric ozone (O3 is quantified in terms of the O3longwave radiative effect (LWRE, which is defined as the net reduction of top-of-atmosphere flux due to total tropospheric O3absorption. The O3LWRE derived from the infrared spectral measurements by Aura’s Tropospheric Emission Spectrometer (TES show that the spatiotemporal variation of LWRE is relevant to relative humidity, surface temperature, and tropospheric O3column. The zonally averaged subtropical LWRE is ~0.2 W m-2higher than the zonally averaged tropical LWRE, generally due to lower water vapor concentrations and less cloud coverage at the downward branch of the Hadley cell in the subtropics. The largest values of O3LWRE over the Middle East (>1 W/m2 are further due to large thermal contrasts and tropospheric ozone enhancements from atmospheric circulation and pollution. Conversely, the low O3LWRE over the Inter-Tropical Convergence Zone (on average 0.4 W m-2 is due to strong water vapor absorption and cloudiness, both of which reduce the tropospheric O3absorption in the longwave radiation. These results show that changes in the hydrological cycle due to climate change could affect the magnitude and distribution of ozone radiative forcing.

  11. AURA 2: Empowering discovery of post-transcriptional networks.

    Science.gov (United States)

    Dassi, Erik; Re, Angela; Leo, Sara; Tebaldi, Toma; Pasini, Luigi; Peroni, Daniele; Quattrone, Alessandro

    2014-01-01

    Post-transcriptional regulation (PTR) of gene expression is now recognized as a major determinant of cell phenotypes. The recent availability of methods to map protein-RNA interactions in entire transcriptomes such as RIP, CLIP and their variants, together with global polysomal and ribosome profiling techniques, are driving the exponential accumulation of vast amounts of data on mRNA contacts in cells, and of corresponding predictions of PTR events. However, this exceptional quantity of information cannot be exploited at its best to reconstruct potential PTR networks, as it still lies scattered throughout several databases and in isolated reports of single interactions. To address this issue, we developed the second and vastly enhanced version of the Atlas of UTR Regulatory Activity (AURA 2), a meta-database centered on mapping interaction of trans-factors with human and mouse UTRs. AURA 2 includes experimentally demonstrated binding sites for RBPs, ncRNAs, thousands of cis-elements, variations, RNA epigenetics data and more. Its user-friendly interface offers various data-mining features including co-regulation search, network generation and regulatory enrichment testing. Gene expression profiles for many tissues and cell lines can be also combined with these analyses to display only the interactions possible in the system under study. AURA 2 aims at becoming a valuable toolbox for PTR studies and at tracing the road for how PTR network-building tools should be designed. AURA 2 is available at http://aura.science.unitn.it.

  12. Magnetic resonance angiography of intracranial and extracranial arteries in patients with spontaneous migraine without aura

    DEFF Research Database (Denmark)

    Amin, Faisal Mohammad; Asghar, Mohammad Sohail; Hougaard, Anders

    2013-01-01

    Extracranial arterial dilatation has been hypothesised to be the cause of pain in patients who have migraine without aura. To test that hypothesis, we aimed to measure extracranial and intracranial arteries during attacks of migraine without aura.......Extracranial arterial dilatation has been hypothesised to be the cause of pain in patients who have migraine without aura. To test that hypothesis, we aimed to measure extracranial and intracranial arteries during attacks of migraine without aura....

  13. Absence of vasoactive peptide release from brain to cerebral circulation during onset of migraine with aura

    DEFF Research Database (Denmark)

    Friberg, L; Olesen, J; Olsen, T S

    1994-01-01

    Xenon-133 injection technique. This technique is known to induce attacks of migraine with aura in many sufferers. Four patients developed aura symptoms. In three this was succeeded by throbbing headache. Typical, migraine-related, focal hypoperfusion occurred in conjunction with the aura symptoms...

  14. Auras in patients with temporal lobe epilepsy and mesial temporal sclerosis.

    Science.gov (United States)

    Asadi-Pooya, Ali A; Nei, Maromi; Sharan, Ashwini; Sperling, Michael R

    2016-05-15

    We investigated auras in patients with drug-resistant temporal lobe epilepsy (TLE) and mesial temporal sclerosis (MTS). We also investigated the clinical differences between patients with MTS and abdominal auras and those with MTS and non-mesial temporal auras. All patients with drug-resistant TLE and unilateral MTS who underwent epilepsy surgery at Jefferson Comprehensive Epilepsy Center from 1986 through 2014 were evaluated. Patients with good postoperative seizure outcome were investigated. One hundred forty-nine patients (71 males and 78 females) were studied. Thirty-one patients (20.8%) reported no auras, while 29 patients (19.5%) reported abdominal aura, and 30 patients (20.1%) reported non-mesial temporal auras; 16 patients (10.7%) had sensory auras, 11 patients (7.4%) had auditory auras, and five patients (3.4%) reported visual auras. A history of preoperative tonic-clonic seizures was strongly associated with non-mesial temporal auras (odds ratio 3.8; 95% CI: 1.15-12.98; p=0.02). About one-fifth of patients who had MTS in their MRI and responded well to surgery reported auras that are historically associated with non-mesial temporal structures. However, the presence of presumed non-mesial temporal auras in a patient with MTS may herald a more widespread epileptogenic zone.

  15. Relationship between primary restless legs syndrome and migraine with aura

    Directory of Open Access Journals (Sweden)

    Bilgehan Atılgan Acar

    2016-08-01

    Full Text Available In this study, the prevalence and characteristics of definite migraine in primary restless legs syndrome (pRLS patients and matched control patients (CPs were investigated. We evaluated 63 consecutive adult pRLS patients and 141 age- and sex-matched controls in this case–control study. The diagnosis of migraine and its subtypes were defined based on The International Classification of Headache Disorders-II. Only those with “definite” migraine were included in the study. The mean age of 63 adult pRLS patients (15 men and 48 women who participated in the study was 49.4 years. A total of 27 patients (42.9% had definite migraine. Of these migraineurs, seven (11.1% were without aura and 20 (31.8% were with aura. The mean age of the 141 matched CPs was 48.7 years. A total of 32 CPs (22.7% experienced migraine. Among these 32 migraineurs, 28 (19.9% were without aura and four (2.8% were with aura. Migraine and migraine with aura were significantly more common in pRLS patients than in CPs. pRLS patients with migraine were more anxious and experienced a shorter duration of RLS symptoms than pRLS patients without migraine. Migraineurs in the pRLS group tended to have high scores for severity of migraine headache by Visual Analog Scale score and high levels of disability by Migraine Disability Assessment grading than those in the control group. pRLS patients showed a positive association with definite migraine headaches. In contrast to results highlighted in recent studies, we found a strong link between migraine with aura and pRLS.

  16. Relationship between primary restless legs syndrome and migraine with aura.

    Science.gov (United States)

    Acar, Bilgehan Atılgan; Acar, Türkan; Alagöz, Aybala Neslihan; Karacan, Alper; Varım, Ceyhun; Uyanık, Mehmet Şevki; Kaya, Tezcan; Akdemir, Ramazan

    2016-08-01

    In this study, the prevalence and characteristics of definite migraine in primary restless legs syndrome (pRLS) patients and matched control patients (CPs) were investigated. We evaluated 63 consecutive adult pRLS patients and 141 age- and sex-matched controls in this case-control study. The diagnosis of migraine and its subtypes were defined based on The International Classification of Headache Disorders-II. Only those with "definite" migraine were included in the study. The mean age of 63 adult pRLS patients (15 men and 48 women) who participated in the study was 49.4 years. A total of 27 patients (42.9%) had definite migraine. Of these migraineurs, seven (11.1%) were without aura and 20 (31.8%) were with aura. The mean age of the 141 matched CPs was 48.7 years. A total of 32 CPs (22.7%) experienced migraine. Among these 32 migraineurs, 28 (19.9%) were without aura and four (2.8%) were with aura. Migraine and migraine with aura were significantly more common in pRLS patients than in CPs. pRLS patients with migraine were more anxious and experienced a shorter duration of RLS symptoms than pRLS patients without migraine. Migraineurs in the pRLS group tended to have high scores for severity of migraine headache by Visual Analog Scale score and high levels of disability by Migraine Disability Assessment grading than those in the control group. pRLS patients showed a positive association with definite migraine headaches. In contrast to results highlighted in recent studies, we found a strong link between migraine with aura and pRLS.

  17. Calcitonin gene-related peptide and migraine with aura

    DEFF Research Database (Denmark)

    Hansen, Jakob M; Ashina, Messoud

    2014-01-01

    BACKGROUND: Calcitonin gene-related peptide (CGRP) is a key molecule in migraine pathophysiology. Most studies have focused on CGRP in relation to migraine without aura (MO). About one-third of migraine patients have attacks with aura (MA), and this is a systematic review of the current literature...... on CGRP and MA. METHODS: We performed a systematic literature search on MEDLINE for reports of CGRP and MA, covering basic science, animal and human studies as well as randomized clinical trials. RESULTS: The literature search identified 594 citations, of which 38 contained relevant, original data. Plasma...

  18. Matrix metalloproteinases during and outside of migraine attacks without aura

    DEFF Research Database (Denmark)

    Ashina, M.; Tvedskov, J.F.; Thiesen, Kerstin Lipka

    2010-01-01

    Ashina M, Tvedskov JF, Lipka K, Bilello J, Penkowa M & Olesen J. Matrix metalloproteinases during and outside of migraine attacks without aura. Cephalalgia 2009. London. ISSN 0333-1024To test the hypothesis that permeability of the blood-brain barrier (BBB) is altered during migraine attack due...... to enhanced activation of matrix metalloproteinases (MMPs), we investigated MMP-3, MMP-9 and tissue inhibitor of metalloproteases (TIMP)-1 in the external jugular vein during and outside of migraine attacks in 21 patients with migraine without aura. In addition, we measured plasma levels of several other...

  19. The Chinese Translation of Walter Benjamin's Aura Revisited%也谈本雅明的aura

    Institute of Scientific and Technical Information of China (English)

    杨俊杰

    2014-01-01

    本雅明的美学概念aura,国内已有多种译法,多从“光”的角度来译,譬如最近甚为流行的“光晕”.但若以德语工具书词条(耶格尔和蒂德曼)、古罗马经典作家用语(贺拉斯和维吉尔)、本雅明同时代作家用词(沃尔夫斯凯尔和施坦纳)这三方面的文献为基础,则可自“气”的角度来译aura,译作“霞气”.

  20. Tsemendirahva kolmekordne pidu / Tapio Aura, Aleksander Nikolajev ; interv. Sulev Oll

    Index Scriptorium Estoniae

    Aura, Tapio

    2005-01-01

    Kunda tsemenditootmisel täitus 135 aastat ja Kunda sadamal 200 aastat. Oma ettevõtete käekäigust räägivad AS-i Kunda Nordic Tsement tegevdirektor Tapio Aura ja Kunda sadama direktor Aleksander Nikolajev

  1. Endothelial Function in Migraine With Aura – A Systematic Review

    DEFF Research Database (Denmark)

    Butt, Jawad H; Franzmann, Ulriche; Kruuse, Christina

    2015-01-01

    BACKGROUND: An increased risk of ischemic stroke is repeatedly reported in young subjects with migraine with aura (MA). Such may be caused by changes in endothelial function. The present review evaluates current evidence on endothelial function in MA patients. METHODS: A systematic search...

  2. Cryptocoryne aura (Araceae), a new species from West Kalimantan, Indonesia

    DEFF Research Database (Denmark)

    Wongso, Suwidji; Ipor, Isa B.; Tawan, Cheksum S.

    2016-01-01

    A new species, Cryptocoryne aura Wongso & Ipor, from West Kalimantan, Indonesia, is described and illustrated. It differs from other Cryptocoryne species primarily by having a transparent, ciliate membrane along the leaf margin and a short spathe with a yellow, forward-twisted limb. It has...

  3. Transient unilateral spatial neglect during aura in a woman with sporadic hemiplegic migraine.

    Science.gov (United States)

    Di Stefano, Francesca; Floris, Gianluca; Vacca, Mariangela; Serra, Giulia; Cannas, Antonino; Borghero, Giuseppe; Marrosu, Maria Giovanna; Marrosu, Francesco

    2013-10-01

    Hemiplegic migraine is a rare form of migraine with aura characterized by motor aura. Although auras in hemiplegic migraine are typically complex with two or more aura symptoms, neglect has been rarely described. We report the case of a 20-year-old woman with sporadic hemiplegic migraine that was investigated for the presence of unilateral spatial neglect (USN) during aura in one of her migraine attacks. Transient hemispatial neglect was observed during a right-sided migraine attack with left sensory-motor hemisyndrome; after migraine resolution there was a total recovery. Our case demonstrates that USN may be a symptom of aura. To our knowledge, this is the first report of USN during aura in an adult with sporadic hemiplegic migraine.

  4. Migraine with persistent aura in a Mexican patient: case report and review of the literature.

    Science.gov (United States)

    San-Juan, O D; Zermeño, P F

    2007-05-01

    Persistent aura symptoms in patients with migraine are rare but well documented. The International Headache Society defines persistent aura without infarction as when the aura symptoms persist for > 1 week without radiographic evidence of infarction. The visual aura of migraine attacks has been explained by cortical spreading depression. We describe a case of a 28-year-old Mexican woman, who presented with persistent aura symptoms, and a literature review. The patient had a 24-year history of migraine headache. In November 2005 the patient had an attack which started with scintillating scotomas bilaterally associated with photopsias and amaurosis followed by migraine headache. All imaging studies were negative. The episode lasted 35 days and probably resolved with nimodipine therapy. Persistent aura symptoms are rare entities. This is the first case documented of a Mexican patient with persistent aura without infarction and probably resolved with nimodipine therapy.

  5. A tropospheric ozone maximum over the equatorial Southern Indian Ocean

    Directory of Open Access Journals (Sweden)

    L. Zhang

    2012-05-01

    Full Text Available We examine the distribution of tropical tropospheric ozone (O3 from the Microwave Limb Sounder (MLS and the Tropospheric Emission Spectrometer (TES by using a global three-dimensional model of tropospheric chemistry (GEOS-Chem. MLS and TES observations of tropospheric O3 during 2005 to 2009 reveal a distinct, persistent O3 maximum, both in mixing ratio and tropospheric column, in May over the Equatorial Southern Indian Ocean (ESIO. The maximum is most pronounced in 2006 and 2008 and less evident in the other three years. This feature is also consistent with the total column O3 observations from the Ozone Mapping Instrument (OMI and the Atmospheric Infrared Sounder (AIRS. Model results reproduce the observed May O3 maximum and the associated interannual variability. The origin of the maximum reflects a complex interplay of chemical and dynamic factors. The O3 maximum is dominated by the O3 production driven by lightning nitrogen oxides (NOx emissions, which accounts for 62% of the tropospheric column O3 in May 2006. We find the contribution from biomass burning, soil, anthropogenic and biogenic sources to the O3 maximum are rather small. The O3 productions in the lightning outflow from Central Africa and South America both peak in May and are directly responsible for the O3 maximum over the western ESIO. The lightning outflow from Equatorial Asia dominates over the eastern ESIO. The interannual variability of the O3 maximum is driven largely by the anomalous anti-cyclones over the southern Indian Ocean in May 2006 and 2008. The lightning outflow from Central Africa and South America is effectively entrained by the anti-cyclones followed by northward transport to the ESIO.

  6. Inducible nitric oxide synthase haplotype associated with migraine and aura.

    Science.gov (United States)

    de O S Mansur, Thiago; Gonçalves, Flavia M; Martins-Oliveira, Alisson; Speciali, Jose G; Dach, Fabiola; Lacchini, Riccardo; Tanus-Santos, Jose E

    2012-05-01

    Migraine is a complex neurological disorder with a clear neurogenic inflammatory component apparently including enhanced nitric oxide (NO) formation. Excessive NO amounts possibly contributing to migraine are derived from increased expression and activity of inducible NO synthase (iNOS). We tested the hypothesis that two functional, clinically relevant iNOS genetic polymorphisms (C(-1026)A-rs2779249 and G2087A-rs2297518) are associated with migraine with or without aura. We studied 142 healthy women without migraine (control group) and 200 women with migraine divided into two groups: 148 with migraine without aura (MWA) and 52 with aura (MA). Genotypes were determined by real-time polymerase chain reaction using the Taqman(®) allele discrimination assays. The PHASE 2.1 software was used to estimate the haplotypes. The A allele for the G2087A polymorphism was more commonly found in the MA group than in the MWA group (28 vs. 18%; P 0.05). The haplotype combining both A alleles for the two polymorphisms was more commonly found in the MA group than in the control group or in the MWA group (19 vs. 10 or 8%; P = 0.0245 or 0.0027, respectively). Our findings indicate that the G2087A and the C(-1026)A polymorphism in the iNOS gene affect the susceptibility to migraine with aura when their effects are combined within haplotypes, whereas the G2087A affects the susceptibility to aura in migraine patients. These finding may have therapeutic implications when examining the effects of selective iNOS inhibitors.

  7. Overview and sample applications of SMILES and Odin-SMR retrievals of upper tropospheric humidity and cloud ice mass

    Science.gov (United States)

    Eriksson, P.; Rydberg, B.; Sagawa, H.; Johnston, M. S.; Kasai, Y.

    2014-12-01

    Retrievals of cloud ice mass and humidity from the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) and the Odin-SMR (Sub-Millimetre Radiometer) limb sounder are presented and example applications of the data are given. SMILES data give an unprecedented view of the diurnal variation of cloud ice mass. Mean regional diurnal cycles are reported and compared to some global climate models. Some improvements in the models regarding diurnal timing and relative amplitude were noted, but the models' mean ice mass around 250 hPa is still low compared to the observations. The influence of the ENSO (El Niño-Southern Oscillation) state on the upper troposphere is demonstrated using 12 years of Odin-SMR data. The same retrieval scheme is applied for both sensors, and gives low systematic differences between the two data sets. A special feature of this Bayesian retrieval scheme, of Monte Carlo integration type, is that values are produced for all measurements but for some atmospheric states retrieved values only reflect a priori assumptions. However, this "all-weather" capability allows a direct statistical comparison to model data, in contrast to many other satellite data sets. Another strength of the retrievals is the detailed treatment of "beam filling" that otherwise would cause large systematic biases for these passive cloud ice mass retrievals. The main retrieval inputs are spectra around 635/525 GHz from tangent altitudes below 8/9 km for SMILES/Odin-SMR, respectively. For both sensors, the data cover the upper troposphere between 30° S and 30° N. Humidity is reported as both relative humidity and volume mixing ratio. The vertical coverage of SMILES is restricted to a single layer, while Odin-SMR gives some profiling capability between 300 and 150 hPa. Ice mass is given as the partial ice water path above 260 hPa, but for Odin-SMR ice water content, estimates are also provided. Besides a smaller contrast between most dry and wet cases, the agreement

  8. Overview and sample applications of SMILES and Odin-SMR retrievals of upper tropospheric humidity and cloud ice mass

    Directory of Open Access Journals (Sweden)

    P. Eriksson

    2014-12-01

    Full Text Available Retrievals of cloud ice mass and humidity from the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES and the Odin-SMR (Sub-Millimetre Radiometer limb sounder are presented and example applications of the data are given. SMILES data give an unprecedented view of the diurnal variation of cloud ice mass. Mean regional diurnal cycles are reported and compared to some global climate models. Some improvements in the models regarding diurnal timing and relative amplitude were noted, but the models' mean ice mass around 250 hPa is still low compared to the observations. The influence of the ENSO (El Niño–Southern Oscillation state on the upper troposphere is demonstrated using 12 years of Odin-SMR data. The same retrieval scheme is applied for both sensors, and gives low systematic differences between the two data sets. A special feature of this Bayesian retrieval scheme, of Monte Carlo integration type, is that values are produced for all measurements but for some atmospheric states retrieved values only reflect a priori assumptions. However, this "all-weather" capability allows a direct statistical comparison to model data, in contrast to many other satellite data sets. Another strength of the retrievals is the detailed treatment of "beam filling" that otherwise would cause large systematic biases for these passive cloud ice mass retrievals. The main retrieval inputs are spectra around 635/525 GHz from tangent altitudes below 8/9 km for SMILES/Odin-SMR, respectively. For both sensors, the data cover the upper troposphere between 30° S and 30° N. Humidity is reported as both relative humidity and volume mixing ratio. The vertical coverage of SMILES is restricted to a single layer, while Odin-SMR gives some profiling capability between 300 and 150 hPa. Ice mass is given as the partial ice water path above 260 hPa, but for Odin-SMR ice water content, estimates are also provided. Besides a smaller contrast between most dry and wet

  9. Effects of the 2006 El Nino on Tropospheric Ozone and Carbon Monoxide: Implications for Dynamics and Biomass Burning

    Science.gov (United States)

    Chandra, S.; Ziemke, J. R.; Duncan, B. N.; Diehl, t. L.

    2008-01-01

    We have studied the effects of the 2006 El Nino on tropospheric O3 and CO at tropical and sub-tropical latitudes measured from the OMI and MLS instruments on the Aura satellite. The 2006 El Nino-induced drought allowed forest fires set to clear land to burn out of control during October and November in the Indonesian region. The effects of these fires are clearly seen in the enhancement of GO concentration measured from the MLS instrument. We have used a global model of atmospheric chemistry and transport (GMI CTM) to quantify the relative irrrportance of biomass burning and large scale transport: in producing observed changes in tropospheric O3 and CO . The model results show that during October and November both biomass burning and meteorological changes contributed almost equally to the observed increase in tropospheric O3 in the Indonesian region. The biomass component was 4-6 DU but it was limited to the Indonesian region where the fires were most intense, The dynamical component was 4-8 DU but it covered a much larger area in the Indian Ocean extending from South East Asia in the north to western Australia in the south. By December 2006, the effect of biomass taming was reduced to zero and the obsemed changes in tropospheric O3 were mostly due to dynamical effects. The model results show an increase of 2-3% in the global burden of tropospheric ozone. In comparison, the global burdean of CO increased by 8-12%.

  10. Impacts of anthropogenic and natural sources on free tropospheric ozone over the Middle East

    Science.gov (United States)

    Jiang, Zhe; Miyazaki, Kazuyuki; Worden, John R.; Liu, Jane J.; Jones, Dylan B. A.; Henze, Daven K.

    2016-05-01

    Significant progress has been made in identifying the influence of different processes and emissions on the summertime enhancements of free tropospheric ozone (O3) at northern midlatitude regions. However, the exact contribution of regional emissions, chemical and transport processes to these summertime enhancements is still not well quantified. Here we focus on quantifying the influence of regional emissions on the summertime O3 enhancements over the Middle East, using updated reactive nitrogen (NOx) emissions. We then use the adjoint of the GEOS-Chem model with these updated NOx emissions to show that the global total contribution of lightning NOx on middle free tropospheric O3 over the Middle East is about 2 times larger than that from global anthropogenic sources. The summertime middle free tropospheric O3 enhancement is primarily due to Asian NOx emissions, with approximately equivalent contributions from Asian anthropogenic activities and lightning. In the Middle Eastern lower free troposphere, lightning NOx from Europe and North America and anthropogenic NOx from Middle Eastern local emissions are the primary sources of O3. This work highlights the critical role of lightning NOx on northern midlatitude free tropospheric O3 and the important effect of the Asian summer monsoon on the export of Asian pollutants.

  11. Reactive nitrogen, ozone and ozone production in the Arctic troposphere and the impact of stratosphere-troposphere exchange

    Directory of Open Access Journals (Sweden)

    Q. Liang

    2011-12-01

    Full Text Available We use aircraft observations obtained during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS mission to examine the distributions and source attributions of O3 and NOy in the Arctic and sub-Arctic region. Using a number of marker tracers, we distinguish various air masses from the background troposphere and examine their contributions to NOx, O3, and O3 production in the Arctic troposphere. The background Arctic troposphere has a mean O3 of ~60 ppbv and NOx of ~25 pptv throughout spring and summer with CO decreasing from ~145 ppbv in spring to ~100 ppbv in summer. These observed mixing ratios are not notably different from the values measured during the 1988 ABLE-3A and the 2002 TOPSE field campaigns despite the significant changes in emissions and stratospheric ozone layer in the past two decades that influence Arctic tropospheric composition. Air masses associated with stratosphere-troposphere exchange are present throughout the mid and upper troposphere during spring and summer. These air masses, with mean O3 concentrations of 140–160 ppbv, are significant direct sources of O3 in the Arctic troposphere. In addition, air of stratospheric origin displays net O3 formation in the Arctic due to its sustainable, high NOx (75 pptv in spring and 110 pptv in summer and NOy (~800 pptv in spring and ~1100 pptv in summer. The air masses influenced by the stratosphere sampled during ARCTAS-B also show conversion of HNO3 to PAN. This active production of PAN is the result of increased degradation of ethane in the stratosphere-troposphere mixed air mass to form CH3CHO, followed by subsequent formation of PAN under high NOx conditions. These findings imply that an adequate representation of stratospheric NOy input, in addition to

  12. First detection of ammonia (NH3) in the upper troposphere

    Science.gov (United States)

    Höpfner, Michael; Volkamer, Rainer; Grabowski, Udo; Grutter de la Mora, Michel; Orphal, Johannes; Stiller, Gabriele; von Clarmann, Thomas

    2016-04-01

    Ammonia (NH3) is the major alkaline trace gas in the troposphere. Neutralization of atmospheric acids, like HNO3 and H2SO4, leads to formation of ammonium nitrate and ammonium sulfate aerosols. Further, there are indications that NH3 may enhance nucleation of sulfuric acid aerosols by stabilization of sulfuric acid clusters. By far the largest source of ammonia is agricultural food production. Major global emissions are located in S-E Asia as e.g. shown by satellite nadir observations. Besides its importance with respect to air quality issues, an increase of ammonia emissions in the 21st century might lead to a significant climate radiative impact through aerosol formation. In spite of its significance, there is a lack of observational information on the global distribution of NH3 in the mid- and upper troposphere. Observational evidence, however, would be important for testing e.g. model results on the fate of ammonia from its source regions on ground to altitudes up to the tropopause. In this contribution we will show, to our knowledge, the first unequivocal detection of ammonia in the upper troposphere. This result has been achieved through analysis of infrared limb-emission observations performed with the MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) instrument on board the Envisat satellite from 2002-2012. On a global scale, enhanced values of ammonia have been measured in the upper tropospheric region influenced by the Asian monsoon. We will present a quantitative analysis of the retrieved concentrations of NH3 including an error assessment and further retrieval diagnostics. The results will be discussed with respect to the variability of NH3 locally within the Asian monsoon region's upper troposphere and at different years. Further, we will show comparisons between global distributions of NH3 from published model simulations and our observational dataset from MIPAS.

  13. A decade of global volcanic SO2 emissions measured from space

    Science.gov (United States)

    Carn, S. A.; Fioletov, V. E.; McLinden, C. A.; Li, C.; Krotkov, N. A.

    2017-03-01

    The global flux of sulfur dioxide (SO2) emitted by passive volcanic degassing is a key parameter that constrains the fluxes of other volcanic gases (including carbon dioxide, CO2) and toxic trace metals (e.g., mercury). It is also a required input for atmospheric chemistry and climate models, since it impacts the tropospheric burden of sulfate aerosol, a major climate-forcing species. Despite its significance, an inventory of passive volcanic degassing is very difficult to produce, due largely to the patchy spatial and temporal coverage of ground-based SO2 measurements. We report here the first volcanic SO2 emissions inventory derived from global, coincident satellite measurements, made by the Ozone Monitoring Instrument (OMI) on NASA’s Aura satellite in 2005-2015. The OMI measurements permit estimation of SO2 emissions from over 90 volcanoes, including new constraints on fluxes from Indonesia, Papua New Guinea, the Aleutian Islands, the Kuril Islands and Kamchatka. On average over the past decade, the volcanic SO2 sources consistently detected from space have discharged a total of ~63 kt/day SO2 during passive degassing, or ~23 ± 2 Tg/yr. We find that ~30% of the sources show significant decadal trends in SO2 emissions, with positive trends observed at multiple volcanoes in some regions including Vanuatu, southern Japan, Peru and Chile.

  14. Nitrogen Oxides in the Arctic Troposphere.

    Science.gov (United States)

    Honrath, Richard Edward, Jr.

    Nitrogen oxides play a critical role in tropospheric photochemistry. In order to characterize these compounds in the arctic troposphere, ground-level concentrations of total reactive nitrogen (NO_{y} ) and NO were determined over an extended period at a site near Barrow, Alaska. A high-sensitivity instrument developed for this purpose was used in three measurement campaigns: summer 1988, spring 1989, and March-December 1990. During the 1990 campaign, the detection limit for NO was 3-10 pptv (depending on averaging period), and the NO_{y} uncertainty was +/-26%. A screening algorithm was applied to the data to eliminate effects from local (Barrow) sources, and the remaining data were divided into "background periods" (unaffected by local or regional NO_ {x} sources), and "events" (periods when emissions from a regional NO_{x} source--the Prudhoe Bay oil-producing region--apparently impacted Barrow). These measurements revealed a sharp seasonal cycle of background NO_{y} concentrations, with high values in early spring (median 560-620 pptv) and ~70 pptv (median) during summer. This cycle is similar to that of other compounds in arctic haze but is partially attributed to a reduction in NO _{y} lifetime due to organic nitrate decomposition as temperatures and insolation increased. Evidence indicates that the springtime arctic NO_{y} reservoir was primarily composed of stable removal-resistant species, including PAN and other organic nitrates. PAN decomposition as temperatures rose in late spring likely caused an observed pulse of NO to ~35 pptv (maximum hourly average); hourly-average NO concentrations were otherwise generally <8 pptv. NO_ {x} production from PAN decomposition due to the onset of spring or southward advection may affect springtime O_3<=vels both in the Arctic and in the northern mid-latitudes. NO_{y} and O _3 concentrations were positively correlated during summer, possibly indicating long-range transport of both and/or the presence of a mid-tropospheric

  15. Long-term trend in tropospheric carbon monoxide over the globe

    Science.gov (United States)

    Girach, I. A.; Nair, Prabha R.

    2016-05-01

    Tropospheric carbon monoxide (CO) is an air pollutant and indirect greenhouse gas which plays a major role in atmospheric chemistry involving hydroxyl (OH) radical. We utilised the remote-sensing retrievals of lower-tropospheric CO (at 900 hPa) from Measurements of Pollution in the Troposphere (MOPITT) aboard Terra-satellite for the period of ~15 years. Using simple linear regression model, we estimated the decreasing trend of ~0-2 %year-1 in the lowertropospheric CO over the globe. Utilising the in-situ measurements of surface-CO over 83 locations carried out by the NOAA (National Oceanic and Atmospheric Administration) network, we confirmed the observed negative trend as surface-CO showed decreasing trend over most of the locations. To estimate the trend in columnar CO, we utilised multiple retrievals of from different satellites, MOPITT, AIRS (Atmospheric InfraRed Sounder), and TES (Tropospheric Emission Spectrometer). All data sets show the decreasing trend of 0.2-0.5 %year-1 in columnar CO when averaged over entire globe. However, the heterogeneity in the trend is observed on regional basis. The retrievals of upper-tropospheric CO (at 200 hPa) from MOPITT and AIRS show an increasing trend of 1-4 %year-1 over the globe. However, the retrievals of upper-tropospheric CO from MLS (Microwave Limb Sounder) show decreasing trend. Further investigations are needed to confirm the trend in the upper-tropospheric CO over the globe. The decreasing trend in lower-tropospheric CO and columnar CO could be due to moistening of troposphere and/or increase in tropospheric ozone, causing increase in OH radical (strengthening the depletion of lower-tropospheric CO).

  16. Jet characterization in the upper troposphere/lower stratosphere (UTLS: applications to climatology and transport studies

    Directory of Open Access Journals (Sweden)

    G. L. Manney

    2011-01-01

    Full Text Available A method of classifying the upper tropospheric/lower stratospheric (UTLS jets has been developed that allows satellite and aircraft trace gas data and meteorological fields to be efficiently mapped in a jet coordinate view. A detailed characterization of multiple tropopauses accompanies the jet characterization. Jet climatologies show the well-known high altitude subtropical and lower altitude polar jets in the upper troposphere, as well as a pattern of concentric polar and subtropical jets in the Southern Hemisphere, and shifts of the primary jet to high latitudes associated with blocking ridges in Northern Hemisphere winter. The jet-coordinate view segregates air masses differently than the commonly-used equivalent latitude (EqL coordinate throughout the lowermost stratosphere and in the upper troposphere. Mapping O3 data from the Aura Microwave Limb Sounder (MLS satellite and the Winter Storms aircraft datasets in jet coordinates highlights important advantages in comparison to an EqL-coordinate view: strong PV, tropopause height and trace gas gradients across the subtropical jet are washed out in the latter and clearly highlighted in the former. The jet coordinate view emphasizes the presence of stratospheric ozone well below the tropopause, especially poleward of and below the jet core, and highlights other transport features associated with the upper tropospheric jets. MLS and Atmospheric Chemistry Experiment-Fourier Transform Spectrometer trace gas fields for spring 2008 in jet coordinates show very strong, closely correlated, PV, tropopause height and trace gas gradients across the jet, and evidence of intrusions of stratospheric air below the tropopause below and poleward of the subtropical jet; these features are consistent between instruments and among multiple trace gases. Our characterization of the jets is facilitating studies that will improve our understanding of upper tropospheric trace gas evolution.

  17. Optimal estimation of tropospheric H2O and δD with IASI/METOP

    Directory of Open Access Journals (Sweden)

    F. Hase

    2011-11-01

    Full Text Available We present optimal estimates of tropospheric H2O and δD derived from radiances measured by the instrument IASI (Infrared Atmospheric Sounding Interferometer flown on EUMETSAT's polar orbiter METOP. We document that the IASI spectra allow for retrieving H2O profiles between the surface and the upper troposphere as well as middle tropospheric δD values. A theoretical error estimation suggests a precision for H2O of better than 35% in the lower troposphere and of better than 15% in the middle and upper troposphere, respectively, whereby surface emissivity and atmospheric temperature uncertainties are the leading error sources. For the middle tropospheric δD values we estimate a precision of 15–20‰ with the measurement noise being the dominating error source. The accuracy of the IASI products is estimated to about 20–10% and 10‰ for lower to upper tropospheric H2O and middle tropospheric δD, respectively. It is limited by systematic uncertainties in the applied spectroscopic parameters and the a priori atmospheric temperature profiles. We compare our IASI products to a large number of near coincident radiosonde in-situ and ground-based FTS (Fourier Transform Spectrometer remote sensing measurements. The bias and the scatter between the different H2O and δD data sets are consistent with the combined theoretical uncertainties of the involved measurement techniques.

  18. Highlights from the 11-year record of tropospheric ozone from OMI/MLS and continuation of that long record using OMPS measurements

    Science.gov (United States)

    Ziemke, Jerry; Kramarova, Natalya; Bhartia, Pawan; Degenstein, Doug; Deland, Matthew

    2016-04-01

    Since October 2004 the Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) onboard the Aura satellite have provided over 11 years of continuous tropospheric ozone measurements. These OMI/MLS measurements have been used in many studies to evaluate dynamical and photochemical effects caused by ENSO, the Madden-Julian Oscillation (MJO) and shorter timescales, as well as long-term trends and the effects of deep convection on tropospheric ozone. Given that the OMI and MLS instruments have now extended well beyond their expected lifetimes, our goal is to continue their long record of tropospheric ozone using recent Ozone Mapping Profiler Suite (OMPS) measurements. The OMPS onboard the Suomi National Polar-orbiting Partnership NPP satellite was launched on October 28, 2011 and is comprised of three instruments: the nadir mapper, the nadir profiler, and the limb profiler. Our study combines total column ozone from the OMPS nadir mapper with stratospheric column ozone from the OMPS limb profiler to measure tropospheric ozone residual. The time period for the OMPS measurements is March 2012 - present. For the OMPS limb profiler retrievals, the OMPS v2 algorithm from Goddard is tested against the SASKatchewan radiative TRANsfer (SASKTRAN) algorithm. The retrieved ozone profiles from each of these algorithms are evaluated with ozone profiles from both ozonesondes and the Aura Microwave Limb Sounder (MLS). Effects on derived OMPS tropospheric ozone caused by the 2015-2016 El Nino event are highlighted. This recent El Nino produced anomalies in tropospheric ozone throughout the tropical Pacific involving increases of ~10 DU over Indonesia and decreases ~5-10 DU in the eastern Pacific. These changes in ozone due to El Nino were predominantly dynamically-induced, caused by the eastward shift in sea-surface temperature and convection from the western to the eastern Pacific.

  19. Distinctive anatomical and physiological features of migraine aura revealed by 18 years of recording.

    Science.gov (United States)

    Hansen, Jakob Møller; Baca, Serapio Michael; Vanvalkenburgh, Paul; Charles, Andrew

    2013-12-01

    The mechanisms underlying the initiation and propagation of the migraine aura, and the visual percept that is produces, remain uncertain. The objective of this study was to characterize and quantify a large number of visual auras recorded by a single individual over nearly two decades to gain insight into basic aura mechanisms. An individual made detailed drawings of his visual percept of migraine aura in real time during more than 1000 attacks of migraine aura without headache over 18 years. Drawings were made in a consistent fashion documenting the shape and location of the aura wavefront or scotoma in the visual field at one minute intervals. These drawings were digitized and the spatial and temporal features of auras were quantified and analysed. Consistent patterns of aura initiation, propagation and termination were observed in both right and left visual fields. Most aura attacks originated centrally (within 10° eccentricity), but there were also other distinct sites of initiation in the visual field. Auras beginning centrally preferentially propagated first through lower nasal field (69-77% of all auras) before travelling to upper and temporal fields, on both sides. Some auras propagated from peripheral to central regions of the visual field-these typically followed the reverse path of those travelling in the opposite direction. The mean velocity of the perceived visual phenomenon did not differ between attacks starting peripherally and centrally. The estimated speed of the underlying cortical event (2-3 mm/min) was in the same range as has been previously reported by others. Some auras had limited propagation and spontaneously 'aborted' after a few minutes, despite being initiated in similar locations to those that spread throughout the entire visual field. The visual percept of the aura changed corresponding with the presumed propagation from the V1 to the V2 region of the occipital cortex. In some cases the visual percept disappeared for several minutes

  20. Migraine with aura and photosensitive epileptic seizures: a case report.

    Science.gov (United States)

    de Carolis, P; Tinuper, P; Sacquegna, T

    1991-07-01

    An 18-year-old female presented with two seizures induced by photic stimulation. She had a positive family history for migraine and a history of febrile convulsions. Since the age of 13 she had suffered from migraine attacks with aura. A brain computerized tomography with contrast enhancement was negative and several electroencephalograms showed a photoparoxysmal response. At the age of 18 she had a partial secondary generalized seizure after photic stimulation during routine electroencephalogram. The onset of seizure was in the occipital region. Two days later, the patient presented with a typical migrainous attack with aura. Interictal apomorphine test (1.5 mg s.c.) blocked the photoparoxysmal response. According to Quesnay, dopaminergic failure of the occipital cortex may account for both epileptic and migraine features.

  1. Sensory migraine aura is not associated with structural grey matter abnormalities

    DEFF Research Database (Denmark)

    Hougaard, Anders; Amin, Faisal Mohammad; Arngrim, Nanna

    2016-01-01

    Migraine with aura (MA) is characterized by cortical dysfunction. Frequent aura attacks may alter cerebral cortical structure in patients, or structural grey matter abnormalities may predispose MA patients to aura attacks. In the present study we aimed to investigate cerebral grey matter structure...... sensory aura regularly. We analysed high-resolution structural MR images using two complimentary approaches and compared patients with and without sensory aura. Patients were also compared to controls. We found no differences of grey matter density or cortical thickness between patients with and without...... sensory aura and no differences for the cortical visual areas between patients and controls. The somatosensory cortex was thinner in patients (1.92 mm vs. 1.96 mm, P = 0.043) and the anterior cingulate cortex of patients had a decreased grey matter density (P = 0.039) compared to controls...

  2. Distinctive anatomical and physiological features of migraine aura revealed by 18 years of recording

    DEFF Research Database (Denmark)

    Hansen, Jakob Møller; Baca, Serapio Michael; Vanvalkenburgh, Paul

    2013-01-01

    or scotoma in the visual field at one minute intervals. These drawings were digitized and the spatial and temporal features of auras were quantified and analysed. Consistent patterns of aura initiation, propagation and termination were observed in both right and left visual fields. Most aura attacks...... originated centrally (within 10° eccentricity), but there were also other distinct sites of initiation in the visual field. Auras beginning centrally preferentially propagated first through lower nasal field (69-77% of all auras) before travelling to upper and temporal fields, on both sides. Some auras...... propagated from peripheral to central regions of the visual field-these typically followed the reverse path of those travelling in the opposite direction. The mean velocity of the perceived visual phenomenon did not differ between attacks starting peripherally and centrally. The estimated speed...

  3. Psychotic aura symptoms in familial hemiplegic migraine type 2 (ATP1A2).

    Science.gov (United States)

    Barros, José; Mendes, Alexandre; Matos, Ilda; Pereira-Monteiro, José

    2012-10-01

    Neuropsychological symptoms are rare in familial hemiplegic migraine (FHM). There are no reports of psychotic symptoms in FHM type 2 (ATP1A2). We examined a family with a FHM phenotype due to a M731T mutation in ATP1A2. A 10-year follow-up allowed us to observe complex auras, including psychotic symptoms in two siblings. Male, 48 years old, with an aura that included complex illusions with a feeling of time travelling, coincident with other aura features. The aura was regarded as mystical by the patient. Female, 38 years old, with a complex migraine aura, during which she believed she had the ability to time travel and was being followed by lobbyists who wanted to steal this ability from her. FHM type 2 must be included in the list of differential diagnoses of acute psychosis in patients with a previous history of migraine aura.

  4. The epileptic aura in literature: aesthetic and philosophical dimensions. An essay.

    Science.gov (United States)

    Wolf, Peter

    2013-03-01

    In literary accounts of epilepsy the aura has a prominent place as the subjective aspect of the seizure experience. Descriptions by authors with their own aura experiences stand out by their precision and authenticity. Many different aura types are mentioned, but the ecstatic aura described by Dostoyevsky has received particular attention and is echoed in many later works. Some authors are interested primarily in the possibilities provided by auras to react, for example, by hiding, seeking help, counteracting the oncoming seizure, or taking measures to prevent damage. Others by their unique aura experiences are inspired to create specific literary flavors like oxymora, spectacular metaphors, or the depiction of complex perceptions and states of mind. Some authors, adding a philosophical dimension, proceed to analyze the consequences of patients' subjective seizure experiences for their identity and their self-perception as creative or religious persons. To sum up, the works discussed herein strongly support that literary texts provide valuable insights beyond those of medical texts.

  5. The occurrence and characteristics of auras in a large epilepsy cohort

    DEFF Research Database (Denmark)

    Nakken, K O; Solaas, M H; Kjeldsen, M J

    2009-01-01

    Objectives - Despite several studies, estimates of the frequency with which auras occur in conjunction with epilepsy continue to be imprecise. The aim of this study was to assess the occurrence and characteristics of auras in a large population-based epilepsy cohort. Materials and methods...... - Subjects with verified epilepsy were recruited from population-based twin registries in the USA, Denmark and Norway. Using a structured interview in which a list of auras was provided, subjects were asked about the warning symptoms preceding their epileptic attacks. Results - 31% of the total sample (n...... = 1897) and 39% of those with active epilepsy (n = 765) had experienced an aura. Six percent reported more than one type. Non-specified auras were most frequently reported (35%), followed by somatosensory (11%) and vertiginous (11%). While the majority of those reporting auras (59%) had focal epilepsies...

  6. Provocation of migraine with aura using natural trigger factors

    DEFF Research Database (Denmark)

    Hougaard, Anders; Amin, Faisal; Hauge, Anne Werner

    2013-01-01

    It is well-known that migraine attacks can be precipitated by various stimuli. More than 50% of patients with migraine with aura (MA) know of at least one stimulus that always or often triggers their MA attacks. The objective of this study was to expose patients with MA to their self-reported tri......-reported trigger factors in order to assess the causal relation between trigger factors and attacks....

  7. Evaluation of Nitrogen Oxides Emissions over California in Spring 2010

    Science.gov (United States)

    Huang, M.; Bowman, K. W.; Carmichael, G. R.; Chai, T.; Pierce, R.; Pollack, I. B.; Ryerson, T. B.

    2013-12-01

    Nitrogen Dioxide (NO2) belongs to the regulated 'six common air pollutants' by the US Environmental Protection Agency (EPA), due to its adverse impacts on the human respiratory system. It is also often used as the indicator for the highly reactive group of gases nitrogen oxides (NOx), the important ozone precursors. We model California air quality during the NOAA CalNex field campaign period in May 2010 using the STEM chemical transport model on a 12 km horizontal resolution grid. Three different anthropogenic emission inventories were used in the simulations: 1) 2005 National Emission Inventory (NEI 2005); 2) daily-varying emissions recently developed by California Air Resources Board (CARB); and 3) NEI 2008. The model-simulated NO2 were compared with the measurements by aircraft and the Ozone Monitoring Instrument (OMI) on board of the Aura satellite. We further conduct NO2 emission inversion using the four-dimensional variational approach [Chai et al., 2009] and the OMI NO2 column data. The inversion generated grid-based emission scaling factors on the NEI 2005, and the resulting NOx fields were 'cross-validated' by comparing with aircraft NO2 measurements. The adjustment on original emissions was then compared with 1) the CARB-documented NOx emission trends, 2) other 'top-down' estimates of California NOx emissions using aircraft measurements [Brioude et al., 2013], and 3) the space-observed NO2 column trends [Russell et al., 2012]. References Chai, T., Carmichael, G., Tang, Y., and Sandu, A., Regional NO2 emission inversion through four-dimensional variational approach using Sciamachy tropospheric column observations, Atmos. Environ., 43, 5046-5055, 2009. Brioude, J., Angevine, W. M., Ahmadov, R., Kim, S.-W., Evan, S., McKeen, S. A., Hsie, E.-Y., Frost, G. J., Neuman, J. A., Pollack, I. B., Peischl, J., Ryerson, T. B., Holloway, J., Brown, S. S., Nowak, J. B., Roberts, J. M., Wofsy, S. C., Santoni, G. W., Oda, T., and Trainer, M.: Top-down estimate of surface

  8. Prolonged symptoms in sporadic hemiplegic migraine: aura or migrainous infarction?

    Science.gov (United States)

    Lai, Tzu-Hsien; Hong, Chien-Tai

    2012-09-01

    Sporadic hemiplegic migraine is a rare form of migraine associated with motor weakness during the aura phase. While the aura usually lasts less than 1 hour, patients with sporadic hemiplegic migraine frequently have prolonged weakness. A 60-year-old male had sporadic hemiplegic migraine after a head injury at the age of 14. He presented to our emergency department with a typical migraine attack except prolonged right limbs weakness and numbness (>1 day). Brain magnetic resonance imaging showed an acute infarction in the left posterior medial pons. He recovered completely from motor weakness but still complained of residual numbness in his right limbs three months later. We report the first adult case of sporadic hemiplegic migraine with migrainous infarction located in the pons. Since patients with hemiplegic migraine often have prolonged aura, it is easy to be confused with a migrainous infarction. The case report highlights that migrainous infarction is a complication difficult to diagnose and treat early, especially in patients with hemiplegic migraine.

  9. Pediatric extratemporal epilepsy presenting with a complex auditory aura.

    Science.gov (United States)

    Clarke, Dave F; Boop, Frederick A; McGregor, Amy L; Perkins, F Frederick; Brewer, Vickie R; Wheless, James W

    2008-06-01

    Ear plugging (placing fingers in or covering the ears) is a clinical seizure semiology that has been described as a response to an unformed, auditory hallucination localized to the superior temporal neocortex. The localizing value of ear plugging in more complex auditory hallucinations may have more involved circuitry. We report on one child, whose aura was a more complex auditory phenomenon, consisting of a door opening and closing, getting louder as the ictus persisted. This child presented, at four years of age, with brief episodes of ear plugging followed by an acute emotional change that persisted until surgical resection of a left mesial frontal lesion at 11 years of age. Scalp video-EEG, magnetic resource imaging, magnetoencephalography, and invasive video-EEG monitoring were carried out. The scalp EEG changes always started after clinical onset. These were not localizing, and encompassed a wide field over the bi-frontal head regions, the left side predominant over the right. Intracranial video-EEG monitoring with subdural electrodes over both frontal and temporal regions localized the seizure-onset to the left mesial frontal lesion. The patient has remained seizure-free since the resection on June 28, 2006, approximately one and a half years ago. Ear plugging in response to simple auditory auras localize to the superior temporal gyrus. If the patient has more complex, formed auditory auras, not only may the secondary auditory areas in the temporal lobe be involved, but one has to entertain the possibility of ictal-onset from the frontal cortex.

  10. New Collections of Aura Atmospheric data Products at the GES DISC

    Science.gov (United States)

    Johnson, James; Ahmad, Suraiya; Gerasimov, Irina; Lepthoukh, Gregory

    2008-01-01

    The NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) is the primary archive of atmospheric composition data from the Aura Ozone Monitoring Instrument (OMI), Microwave Limb sounder (MLS), and High-Resolution Dynamics Limb Sounder (HIRDLS) instruments. The most recent versions of Aura OMI, MLS and HIRDLS data are available free to the public (http://disc.gsfc.nasa.gov/Aura). TES data are at ASDC (http://eosweb.larc.nasa.gov).

  11. An aura of confusion: 'seeing auras-vital energy or human physiology?' Part 1 of a three part series.

    Science.gov (United States)

    Duerden, Tim

    2004-02-01

    The first of three papers that considers claims made for the perception or detection of vital energy. Many systems of Complementary and Alternative Medicine (CAM) assume the existence of a vital force that mediates therapeutic efficacy, for example chi or qi in Traditional Chinese medicine. Vital energy directly perceived or imaged that surrounds living organisms is frequently termed the aura. This paper aims to show how phenomena that arise as a consequence of the normal functioning of the human visual system can be inappropriately offered as support of claims for the direct perception of vital energy or the aura. Specifically, contrast and complementary colour phenomena, entoptic phenomena and the deformation phosphene, the 'flying corpuscle effect', the blind spot and the 'reverse telescope effect' are explained and discussed.

  12. Ozone in the Tropical Troposphere

    NARCIS (Netherlands)

    Peters, Wouter

    2003-01-01

    The aim of the research presented here is to acquire knowledge of the past, present, and future composition, stability, sensitivity, and variability of the troposphere. We focus mostly on the tropical regions because it has received little attention so far, measurements here are scarce, and large ch

  13. Plant responses to tropospheric ozone

    Science.gov (United States)

    Tropospheric ozone is the second most abundant air pollutant and an important component of the global climate change. Over five decades of research on the phytotoxicity of ozone in model plants systems, crop plants and forest trees have provided some insight into the physiological, biochemical and m...

  14. Can a 'state of the art' chemistry transport model really simulate Anazonian tropospheric chemistry

    NARCIS (Netherlands)

    Barkley, M.; Palmer, P.I.; Ganzeveld, L.N.

    2011-01-01

    We present an evaluation of a nested high-resolution Goddard Earth Observing System (GEOS)-Chem chemistry transport model simulation of tropospheric chemistry over tropical South America. The model has been constrained with two isoprene emission inventories: (1) the canopy-scale Model of Emissions

  15. Greater occipital nerve block for the acute treatment of prolonged or persistent migraine aura.

    Science.gov (United States)

    Cuadrado, María L; Aledo-Serrano, Ángel; López-Ruiz, Pedro; Gutiérrez-Viedma, Álvaro; Fernández, Cristina; Orviz, Aida; Arias, José A

    2017-07-01

    Background Presently, there is no evidence to guide the acute treatment of migraine aura. We aimed to describe the effect of greater occipital nerve (GON) anaesthetic block as a symptomatic treatment for long-lasting (prolonged or persistent) migraine aura. Methods Patients who presented with migraine aura lasting > 2 hours were consecutively recruited during one year at the Headache Unit and the Emergency Department of a tertiary hospital. All patients underwent a bilateral GON block with bupivacaine 0.5%. Patients were followed up for 24 hours. Results A total of 22 auras were treated in 18 patients. Auras consisted of visual ( n = 13), visual and sensory ( n = 4) or sensory symptoms alone ( n = 5). Eleven episodes met diagnostic criteria for persistent aura (>1 week) without infarction. The response was complete without early recurrence in 11 cases (50%), complete with recurrence in auras lasting auras (72.7% vs. 27.3%; p = 0.033). Conclusions GON block could be an effective symptomatic treatment for prolonged or persistent migraine aura. Randomised controlled trials are still required to confirm these results.

  16. 'Visual snow' - a disorder distinct from persistent migraine aura.

    Science.gov (United States)

    Schankin, Christoph J; Maniyar, Farooq H; Digre, Kathleen B; Goadsby, Peter J

    2014-05-01

    Patients with 'visual snow' report continuous tiny dots in the entire visual field similar to the noise of an analogue television. As they frequently have migraine as a comorbidity with ophthalmological, neurological and radiological studies being normal, they are offered various diagnoses, including persistent migraine aura, post-hallucinogen flashback, or psychogenic disorder. Our aim was to study patients with 'visual snow' to characterize the phenotype. A three-step approach was followed: (i) a chart review of patients referred to us identified 22 patients with 'visual snow'. Fifteen had additional visual symptoms, and 20 patients had comorbid migraine, five with aura; (ii) to identify systematically additional visual symptoms, an internet survey (n = 275) of self-assessed 'visual snow' subjects done by Eye On Vision Foundation was analysed. In two random samples from 235 complete data sets, the same eight additional visual symptoms were present in >33% of patients: palinopsia (trailing and afterimages), entoptic phenomena (floaters, blue field entoptic phenomenon, spontaneous photopsia, self-light of the eye), photophobia, and nyctalopia (impaired night vision); and (iii) a prospective semi-structured telephone interview in a further 142 patients identified 78 (41 female) with confirmed 'visual snow' and normal ophthalmological exams. Of these, 72 had at least three of the additional visual symptoms from step (ii). One-quarter of patients had 'visual snow' as long as they could remember, whereas for the others the mean age of onset was 21 ± 9 years. Thirty-two patients had constant visual symptoms, whereas the remainder experienced either progressive or stepwise worsening. Headache was the most frequent symptom associated with the beginning or a worsening of the visual disturbance (36%), whereas migraine aura (seven patients) and consumption of illicit drugs (five, no hallucinogens) were rare. Migraine (59%), migraine with aura (27%), anxiety and depression

  17. The influence of African air pollution on regional and global tropospheric ozone

    Directory of Open Access Journals (Sweden)

    A. M. Aghedo

    2007-01-01

    Full Text Available We investigate the influence of African biomass burning, biogenic, lightning and anthropogenic emissions on the tropospheric ozone over Africa and globally using a coupled global chemistry climate model. Our model studies indicate that surface ozone concentration may rise by up to 50 ppbv in the burning region during the biomass burning seasons. Biogenic emissions yield between 5–30 ppbv increase in the near surface ozone concentration over tropical Africa. The impact of lightning on surface ozone is negligible, while anthropogenic emissions yield a maximum of 7 ppbv increase in the annual-mean surface ozone concentration over Nigeria, South Africa and Egypt. Our results show that biogenic emissions are the most important African emission source affecting total tropospheric ozone. The influence of each of the African emissions on the global tropospheric ozone burden (TOB of 384 Tg yields about 9.5 Tg, 19.6 Tg, 9.0 Tg and 4.7 Tg for biomass burning, biogenic, lightning and anthropogenic emissions emitted in Africa respectively. The impact of each of these emission categories on African TOB of 33 Tg is 2.5 Tg, 4.1 Tg, 1.75 Tg and 0.89 Tg respectively, which together represents about 28% of the total TOB calculated over Africa. Our model calculations also suggest that more than 70% of the tropospheric ozone produced by each of the African emissions is found outside the continent, thus exerting a noticeable influence on a large part of the tropical troposphere. Apart from the Atlantic and Indian Ocean, Latin America experiences the largest impact of African emissions, followed by Oceania, the Middle East, Southeast and south-central Asia, northern North America (i.e. the United States and Canada, Europe and north-central Asia, for all the emission categories.

  18. Sensory migraine aura is not associated with structural grey matter abnormalities.

    Science.gov (United States)

    Hougaard, Anders; Amin, Faisal Mohammad; Arngrim, Nanna; Vlachou, Maria; Larsen, Vibeke Andrée; Larsson, Henrik B W; Ashina, Messoud

    2016-01-01

    Migraine with aura (MA) is characterized by cortical dysfunction. Frequent aura attacks may alter cerebral cortical structure in patients, or structural grey matter abnormalities may predispose MA patients to aura attacks. In the present study we aimed to investigate cerebral grey matter structure in a large group of MA patients with and without sensory aura (i.e. gradually developing, transient unilateral sensory disturbances). We included 60 patients suffering from migraine with typical visual aura and 60 individually age and sex-matched controls. Twenty-nine of the patients additionally experienced sensory aura regularly. We analysed high-resolution structural MR images using two complimentary approaches and compared patients with and without sensory aura. Patients were also compared to controls. We found no differences of grey matter density or cortical thickness between patients with and without sensory aura and no differences for the cortical visual areas between patients and controls. The somatosensory cortex was thinner in patients (1.92 mm vs. 1.96 mm, P = 0.043) and the anterior cingulate cortex of patients had a decreased grey matter density (P = 0.039) compared to controls. These differences were not correlated to the clinical characteristics. Our results suggest that sensory migraine aura is not associated with altered grey matter structure and that patients with visual aura have normal cortical structure of areas involved in visual processing. The observed decreased grey matter volume of the cingulate gyrus in patients compared to controls have previously been reported in migraine with and without aura, but also in a wide range of other neurologic and psychiatric disorders. Most likely, this finding reflects general bias between patients and healthy controls.

  19. Coincidental impact of transcatheter patent foramen ovale closure on migraine with and without aura — A comprehensive meta-analysis

    Directory of Open Access Journals (Sweden)

    Siddak M. Kanwar

    2016-03-01

    Conclusions: Among patients with unexplained stroke and migraine undergoing transcatheter PFO closure, resolution of headaches occurred in a majority of patients with aura and for a smaller proportion of patients without aura.

  20. Southern Hemisphere Additional Ozonesondes (SHADOZ) Ozone Climatology (2005-2009): Tropospheric and Tropical Tropopause Layer (TTL) Profiles with Comparisons to Omi-based Ozone Products

    Science.gov (United States)

    Thompson, Anne M.; Miller, Sonya K.; Tilmes, Simone; Kollonige, Debra W.; Witte, Jacquelyn C.; Oltmans, Samuel J.; Johnson, Brian J.; Fujiwara, Masatomo; Schmidlin, F. J.; Coetzee, G. J. R.; Komala, Ninong; Maata, Matakite; bt Mohammad, Maznorizan; Nguyo, J.; Mutai, C.; Ogino, S-Y; Da Silva, F. Raimundo; Paes Leme, N. M.; Posny, Francoise; Scheele, Rinus; Selkirk, Henry B.; Shiotani, Masato; Stubi, Rene; Levrat, Gilbert; Calpini, Bertrand; Thouret, Valerie; Tsuruta, Haruo; Canossa, Jessica Valverde; Voemel, Holger; Yonemura, S.; Andres Diaz, Jorge; Tan Thanh, Nguyen T.; Thuy Ha, Hoang T.

    2012-01-01

    We present a regional and seasonal climatology of SHADOZ ozone profiles in the troposphere and tropical tropopause layer (TTL) based on measurements taken during the first five years of Aura, 2005-2009, when new stations joined the network at Hanoi, Vietnam; Hilo, Hawaii; Alajuela Heredia, Costa Rica; Cotonou, Benin. In all, 15 stations operated during that period. A west-to-east progression of decreasing convective influence and increasing pollution leads to distinct tropospheric ozone profiles in three regions: (1) western Pacific eastern Indian Ocean; (2) equatorial Americas (San Cristobal, Alajuela, Paramaribo); (3) Atlantic and Africa. Comparisons in total ozone column from soundings, the Ozone Monitoring Instrument (OMI, on Aura, 2004-) satellite and ground-based instrumentation are presented. Most stations show better agreement with OMI than they did for EPTOMS comparisons (1998-2004; Earth-ProbeTotal Ozone Mapping Spectrometer), partly due to a revised above-burst ozone climatology. Possible station biases in the stratospheric segment of the ozone measurement noted in the first 7 years of SHADOZ ozone profiles are re-examined. High stratospheric bias observed during the TOMS period appears to persist at one station. Comparisons of SHADOZ tropospheric ozone and the daily Trajectory-enhanced Tropospheric Ozone Residual (TTOR) product (based on OMIMLS) show that the satellite-derived column amount averages 25 low. Correlations between TTOR and the SHADOZ sondes are quite good (typical r2 0.5-0.8), however, which may account for why some published residual-based OMI products capture tropospheric interannual variability fairly realistically. On the other hand, no clear explanations emerge for why TTOR-sonde discrepancies vary over a wide range at most SHADOZ sites.

  1. 75 FR 13806 - Culturally Significant Objects Imported for Exhibition Determinations: “Loan From the Aura...

    Science.gov (United States)

    2010-03-23

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF STATE Culturally Significant Objects Imported for Exhibition Determinations: ``Loan From the Aura Collection of a... hereby determine that the object to be included in the exhibition ``Loan from the Aura Collection of...

  2. Cerebral oxygen extraction, oxygen consumption, and regional cerebral blood flow during the aura phase of migraine

    DEFF Research Database (Denmark)

    Friberg, L; Olesen, Jes; Lassen, N A

    1994-01-01

    The aura phase of migraine is associated with focal blood flow changes, but it has been largely unknown whether these changes are correlated to changes in the cerebral metabolism.......The aura phase of migraine is associated with focal blood flow changes, but it has been largely unknown whether these changes are correlated to changes in the cerebral metabolism....

  3. Global Gravity Wave Variances from Aura MLS: Characteristics and Interpretation

    Science.gov (United States)

    Wu, Dong L.; Eckermann, Stephen D.

    2008-01-01

    The gravity wave (GW)-resolving capabilities of 118-GHz saturated thermal radiances acquired throughout the stratosphere by the Microwave Limb Sounder (MLS) on the Aura satellite are investigated and initial results presented. Because the saturated (optically thick) radiances resolve GW perturbations from a given altitude at different horizontal locations, variances are evaluated at 12 pressure altitudes between 21 and 51 km using the 40 saturated radiances found at the bottom of each limb scan. Forward modeling simulations show that these variances are controlled mostly by GWs with vertical wavelengths z 5 km and horizontal along-track wavelengths of y 100-200 km. The tilted cigar-shaped three-dimensional weighting functions yield highly selective responses to GWs of high intrinsic frequency that propagate toward the instrument. The latter property is used to infer the net meridional component of GW propagation by differencing the variances acquired from ascending (A) and descending (D) orbits. Because of improved vertical resolution and sensitivity, Aura MLS GW variances are 5?8 times larger than those from the Upper Atmosphere Research Satellite (UARS) MLS. Like UARS MLS variances, monthly-mean Aura MLS variances in January and July 2005 are enhanced when local background wind speeds are large, due largely to GW visibility effects. Zonal asymmetries in variance maps reveal enhanced GW activity at high latitudes due to forcing by flow over major mountain ranges and at tropical and subtropical latitudes due to enhanced deep convective generation as inferred from contemporaneous MLS cloud-ice data. At 21-28-km altitude (heights not measured by the UARS MLS), GW variance in the tropics is systematically enhanced and shows clear variations with the phase of the quasi-biennial oscillation, in general agreement with GW temperature variances derived from radiosonde, rocketsonde, and limb-scan vertical profiles.

  4. Study on the regional and global rise in NO{sub x} and non-methane hydrocarbon concentrations in the upper troposphere and lower stratosphere as a consequence of airplane emissions. Final report; Untersuchungen zur regionalen und globalen Erhoehung der NO{sub x}- und Nichtmethankohlenwasserstoff-Konzentrationen in der oberen Troposphaere und der unteren Stratosphaere infolge Flugzeugemissionen. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Rohrer, F.

    1996-01-05

    In this project a chemical mechanism was developed for the upper troposphere which permits examining the photochemical formation of ozone. Using this mechanism it was found that at medium latitudes (at 10 km altitude in June) hydroxyl radical concentration and the rate of photochemical ozone formation to which it is coupled depend on NO{sub x} concentrations in a strongly non-linear manner, peaking at 110 ppt NO{sub x} and 200 pp NO{sub x}, respectively. Regarding the assessment of the effects of air traffic it was thus shown that in attempting to forecast changes in ozone concentration one must not only take aviation-related changes in NO{sub x} concentrations into account but also the forecasted absolute concentrations of NO{sub x}. The measured data were interpreted by combining a simplified model of NO{sub x} reactions with an existing three-dimensional transport model and comparing the measured and the calculated vertical NO profiles. It can be said that the 3D chemical transport model supplies realistic tropospheric NO{sub x} ratios at least for medium latitudes (49 to 56 N) in the months of May, June, July, December, and January. At these latitudes the tropospheric NO{sub x} budget is mainly governed by anthropogenic emissions. (orig./KW) [Deutsch] In diesem Projekt wurde ein Chemiemechanismus fuer die obere Troposphaere entwickelt, der es erlaubt, die photochemische Ozonbildung zu untersuchen. Mit diesem Mechanismus konnte fuer mittlere noerdliche Breiten (fuer 10 km Hoehe, Juni) gezeigt werden, dass die Hydroxylradikalkonzentration und die damit gekoppelte photochemische Ozonbildungsrate in stark nichtlinearer Weise von der Stickoxidkonzentration abhaengen und bei etwa 110 ppt NO{sub x} (bezw. 200 ppt NO{sub x} fuer die Ozonbildungsrate) ein Maximum durchlaufen. Fuer die Beurteilung der Auswirkungen des Flugverkehrs konnte deswegen gezeigt werden, dass die Voraussagen ueber Ozonveraenderungen nicht nur von der Aenderung der Stickoxidkonzentration durch den

  5. Development of a Climate Record of Tropospheric and Stratospheric Column Ozone from Satellite Remote Sensing: Evidence of an Early Recovery of Global Stratospheric Ozone

    Science.gov (United States)

    Ziemke, Jerald R.; Chandra, Sushil

    2012-01-01

    Ozone data beginning October 2004 from the Aura Ozone Monitoring Instrument (OMI) and Aura Microwave Limb Sounder (MLS) are used to evaluate the accuracy of the Cloud Slicing technique in effort to develop long data records of tropospheric and stratospheric ozone and for studying their long-term changes. Using this technique, we have produced a 32-yr (1979-2010) long record of tropospheric and stratospheric column ozone from the combined Total Ozone Mapping Spectrometer (TOMS) and OMI. Analyses of these time series suggest that the quasi-biennial oscillation (QBO) is the dominant source of inter-annual variability of stratospheric ozone and is clearest in the Southern Hemisphere during the Aura time record with related inter-annual changes of 30- 40 Dobson Units. Tropospheric ozone for the long record also indicates a QBO signal in the tropics with peak-to-peak changes varying from 2 to 7 DU. The most important result from our study is that global stratospheric ozone indicates signature of a recovery occurring with ozone abundance now approaching the levels of year 1980 and earlier. The negative trends in stratospheric ozone in both hemispheres during the first 15 yr of the record are now positive over the last 15 yr and with nearly equal magnitudes. This turnaround in stratospheric ozone loss is occurring about 20 yr earlier than predicted by many chemistry climate models. This suggests that the Montreal Protocol which was first signed in 1987 as an international agreement to reduce ozone destroying substances is working well and perhaps better than anticipated.

  6. Development of a climate record of tropospheric and stratospheric column ozone from satellite remote sensing: evidence of an early recovery of global stratospheric ozone

    Directory of Open Access Journals (Sweden)

    J. R. Ziemke

    2012-07-01

    Full Text Available Ozone data beginning October 2004 from the Aura Ozone Monitoring Instrument (OMI and Aura Microwave Limb Sounder (MLS are used to evaluate the accuracy of the Cloud Slicing technique in effort to develop long data records of tropospheric and stratospheric ozone and for studying their long-term changes. Using this technique, we have produced a 32-yr (1979–2010 long record of tropospheric and stratospheric column ozone from the combined Total Ozone Mapping Spectrometer (TOMS and OMI. Analyses of these time series suggest that the quasi-biennial oscillation (QBO is the dominant source of inter-annual variability of stratospheric ozone and is clearest in the Southern Hemisphere during the Aura time record with related inter-annual changes of 30–40 Dobson Units. Tropospheric ozone for the long record also indicates a QBO signal in the tropics with peak-to-peak changes varying from 2 to 7 DU. The most important result from our study is that global stratospheric ozone indicates signature of a recovery occurring with ozone abundance now approaching the levels of year 1980 and earlier. The negative trends in stratospheric ozone in both hemispheres during the first 15 yr of the record are now positive over the last 15 yr and with nearly equal magnitudes. This turnaround in stratospheric ozone loss is occurring about 20 yr earlier than predicted by many chemistry climate models. This suggests that the Montreal Protocol which was first signed in 1987 as an international agreement to reduce ozone destroying substances is working well and perhaps better than anticipated.

  7. [Aura-related symptoms associated with cluster headache: outcomes of a LUCA substudy].

    Science.gov (United States)

    Wilbrink, L A; Cheung, Carlo; Weller, Claudia M; Ferrari, Michel D; Haan, Joost

    2013-01-01

    To describe the prevalence of aura in a Dutch cluster headache (CH) population. Cross-sectional, epidemiological study. As part of a large-scale study into headaches conducted in Leiden (the Netherlands), patients experiencing headaches were identified by means of questionnaires on a headache website. One group of patients with CH was approached by telephone and an interview on aura-related symptoms was performed by means of a standardized questionnaire. The presence of migraine co-morbidity was also investigated. Of the interviewed CH patients, 22 out of 244 (9.0%) had aura-related symptoms preceding a CH attack, which were predominantly visual in nature. The majority (72.7%) of these patients did not have migraine co-morbidity. Aura-related symptoms can occur in CH without migraine co-morbidity. In clinical practice, it should be taken into account that the presence of an aura does not always indicate migraine.

  8. Iatrogenic visual aura: a case report and a brief review of the literature.

    Science.gov (United States)

    Buture, Alina; Khalil, Modar; Ahmed, Fayyaz

    2017-01-01

    Iatrogenic migraine aura following transseptal catheterization has only rarely been reported in the literature. We report the case of a 60-year-old female who presented with new onset of migraine with visual aura 1 day after transseptal cryoballoon catheter ablation for atrial fibrillation. The patient had a 5-year history of typical migraine without aura and had never experienced visual aura before the cardiac intervention. The neurological examination, fundoscopy, and blood tests were normal. The magnetic resonance imaging of the brain showed small vessel ischemia without evidence of vessel ischemic changes in the occipital lobes and large blood vessel disease. A change in the characteristics of existing migraine could occur following an iatrogenic episode, which in this case was catheter ablation for atrial fibrillation. A new onset of aura is considered an indication for a brain scan as it may signify underlying new pathology.

  9. IIP Tropospheric Infrared Mapping Spectrometers (TIMS) demonstration of CO retrieval, including multi-layer, from atmospheric data acquired simultaneously in the solar reflective region near 2.3 um and the thermal emissive region near 4.7 um

    Science.gov (United States)

    Mergenthaler, J. L.; Kumer, J.; Roche, A. E.; Rairden, R. L.; Blatherwick, R.; Hawat, T.; Desouza-Machado, S.; Hannon, S.; Chatfield, R. B.

    2008-12-01

    The NASA Earth Science Technology Office (ESTO) Instrument Incubator Program (IIP) Tropospheric Infrared Mapping Spectrometers (TIMS) have been developed to demonstrate measurement capability, when deployed in space, for multi-layer retrieval of CO from spectral measurements acquired in the solar reflective (SR) region ~ 4281 to 4301 cm-1 and in the thermal InfraRed (TIR) region ~ 2110 to 2165 cm-1. We describe joint deployment at Denver University (DU) with co-investigators there of the TIMS, and of the DU colleagues FTS, to acquire simultaneous measurements of atmospheric spectra in the SR and the TIR. The FTS provided validation radiance data for the TIMS. The TIMS retrievals of CO, H2O and CH4 agreed well with validation vs these as retrieved from the DU data, AIRS retrieval, standard models and ECMWF. The TIMS CO retrievals included column retrieved from the just the SR data, column retrieved from just the TIR data, and a simple two-layer retrieval from the combined data sets. The data were acquired in an operational mode that mimicked the operations in a conceptual application that would provide footprints, coverage, refresh time as in the Decadal Survey GEO-CAPE mission statement. Very encouraging CO precisions were achieved, e.g., the TIMS CO column retrieval from the SR data demonstrated better than the 10% precision requirement as listed on slide 32 of the GEO-CAPE Reference document http://geo- cape.larc.nasa.gov/docs/GEOMAC_FinalReport_no_costs.ppt

  10. Variations of tropospheric methane over Japan during 1988–2010

    Directory of Open Access Journals (Sweden)

    Taku Umezawa

    2014-05-01

    Full Text Available We present observations of CH4 concentrations from the lower to upper troposphere (LT and UT over Japan during 1988–2010 based on aircraft measurements from the Tohoku University (TU. The analysis is aided by simulation results using an atmospheric chemistry transport model (i.e. ACTM. Tropospheric CH4 over Japan shows interannual and seasonal variations that are dependent on altitudes, primarily reflecting differences in air mass origins at different altitudes. The long-term trend and interannual variation of CH4 in the LT are consistent with previous reports of measurements at surface baseline stations in the northern hemisphere. However, those in the UT show slightly different features from those in the LT. In the UT, CH4 concentrations show a seasonal maximum in August due to efficient transport of air masses influenced by continental CH4 sources, while LT CH4 reaches its seasonal minimum during summer due to enhanced chemical loss. Vertical profiles of the CH4 concentrations also vary with season, reflecting the seasonal cycles at the respective altitudes. In summer, transport of CH4-rich air from Asian regions elevates UT CH4 levels, forming a uniform vertical profile above the mid-troposphere. On the other hand, CH4 decreases nearly monotonically with altitude in winter–spring. The ACTM simulations with different emission scenarios reproduce general features of the tropospheric CH4 variations over Japan. Tagged tracer simulations using the ACTM indicate substantial contributions of CH4 sources in South Asia and East Asia to the summertime high CH4 values observed in the UT. This suggests that our observations over Japan are highly sensitive to CH4 emission signals particularly from Asia.

  11. Pattern reversal visual evoked potentials in migraine subjects without aura

    Directory of Open Access Journals (Sweden)

    Pedro F. Moreira Filho

    1994-12-01

    Full Text Available Twenty seven patients with migraine without aura were investigated. The age was between 12 and 54 years; 5 were men and 22 women. The diagnosis of migraine was made according to the classification proposed by the International Headache Society. The method of visual evoked potential was performed with pattern reversal (VEP-PR, with monocular stimulation. The stimulation was performed with pattern reversal with 4x4 cm black and white and red and green squared screen placed 1 meter from the nasion at stimulus frequency 1/s; 128 individual trials were analysed. The VEP-PR with black/white and red/green study showed a significant increase of value of the P-100 latency in 10 migraine patients. In 8 cases the LP100 in VEP-PR black/white was normal but in VEP-PR red/green the LP100 showed increase. Specifically in 1 of our cases, LP100 were normal in VEP-PR black/white but in the red/green there were no reproductice waves. On basis of these observations we consider that the method of VEP-PR is an useful instrument for investigation of migraine patients without aura.

  12. Characteristics of Water Vapor in the UTLS over the Tibetan Plateau Based on AURA/MLS Observations

    Directory of Open Access Journals (Sweden)

    Yi Sun

    2017-01-01

    Full Text Available Water vapor (WV has a vital effect on global climate change. Using satellite data observed by AURA/MLS and ERA-Interim reanalysis datasets, the spatial distributions and temporal variations of WV were analyzed. It was found that high WV content in the UTLS over the southern Tibetan Plateau is more apparent in summer, due to monsoon-induced strong upward motions. The WV content showed the opposite distribution at 100 hPa, though, during spring and winter. And a different distribution at 121 hPa indicated that the difference in WV content between the northern and southern plateau occurs between 121 and 100 hPa in spring and between 147 and 121 hPa in winter. In the UTLS, it diminishes rapidly with increase in altitude in these two seasons, and it shows a “V” structure in winter. There has been a weak increasing trend in WV at 100 hPa, but a downtrend at 147 and 215 hPa, during the past 12 years. At the latter two heights, the WV content in summer has been much higher than in other seasons. Furthermore, WV variation showed a rough wave structure in spring and autumn at 215 hPa. The variation of WV over the Tibetan Plateau is helpful in understanding the stratosphere-troposphere exchange (STE and climate change.

  13. BRAM: a reanalysis of Aura MLS chemical observations by the Belgian Assimilation System for Chemical ObsErvations

    Science.gov (United States)

    Errera, Quentin; Braathen, Geir; Chabrillat, Simon; Christophe, Yves; Santee, Michelle; Skachko, Sergey

    2017-04-01

    BRAM is a reanalysis of Aura MLS observations produced by the Belgian Assimilation System of Chemical ObsErvations (BASCOE). BASCOE is based on a chemistry transport model (CTM) for the stratosphere involving 58 species. All species are advected by the Flux Form Semi-Lagrangian (FFSL) scheme (i.e. Lin and Rood, 1996). The CTM account for gas phase, photolysis and heterogeneous reactions relevant for the stratosphere. Micro-physics of Polar Stratospheric Cloud (PSC) is also taken into account in the model by a simple parameterization. For this study, the model is driven by ERA-Interim dynamical fields. The horizontal resolution is set to 2.5° in latitude and 3.75° in longitude. Vertically, the model has 37 levels from the surface to 0.1 hPa which correspond to the ERA-Interim levels in the stratosphere and a subset of them in the troposphere. BASCOE can be run in 4D-Var or EnKF and for BRAM, the EnKF method has been used. The period of the reanalysis starts in August 2004, at the beginning of the MLS mission, and go up to the present. Assimilated species are MLS retrieved profiles of O3, CO, H2O, N2O, HNO3, HCl, ClO and CH3Cl. This contribution will present the setup of BASCOE, the evaluation of BRAM and the way to get the data.

  14. Instrumentation for tropospheric aerosol characterization

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Z.; Young, S.E.; Becker, C.H.; Coggiola, M.J. [SRI International, Menlo Park, CA (United States); Wollnik, H. [Giessen Univ. (Germany)

    1997-12-31

    A new instrument has been developed that determines the abundance, size distribution, and chemical composition of tropospheric and lower stratospheric aerosols with diameters down to 0.2 {mu}m. In addition to aerosol characterization, the instrument also monitors the chemical composition of the ambient gas. More than 25.000 aerosol particle mass spectra were recorded during the NASA-sponsored Subsonic Aircraft: Contrail and Cloud Effects Special Study (SUCCESS) field program using NASA`s DC-8 research aircraft. (author) 7 refs.

  15. Partner with the Experts: The EOS Aura Education and Public Outreach Strategy

    Science.gov (United States)

    Stockman, S.

    2001-12-01

    One of the challenges faced by NASA satellite missions is the creation and distribution educational and public outreach (EPO) material with a limited amount funding. This paper will detail the approach developed to support EOS Aura, a four-instrument atmospheric chemistry satellite that will launch in 2003. The mission focuses on collecting data to help answer three major science questions: Is the Earth's ozone layer recovering? Is air quality getting worse? How is Earth's climate changing? The Aura project has created several strategic partnerships within the formal and informal education communities that facilitate the development and dissemination of materials to foster the understanding of the Aura mission and its major science questions. Partners and programs include the American Chemical Society ChemMatters magazine, the Smithsonian Institution National Museum of Natural History "Forces of Change" program, and the GLOBE Program. Each of the Aura EPO collaborations is built around pre-existing programs within the partner organizations. The partner organizations bring formal and informal education expertise, pre-existing education products, networks of educators, and large target audiences to the Aura EPO program. The Aura mission provides funding, science and technological expertise, materials created for the mission such as physical models and scientific visualizations, as well as access to NASA's nationwide education network. The goal is to leverage limited EPO resources to reach educators, students and the public through a variety of mechanisms. This talk will highlight projects that have resulted from the Aura EPO strategic partnerships.

  16. Epileptic auras and their role in driving safety in people with epilepsy.

    Science.gov (United States)

    Punia, Vineet; Farooque, Pue; Chen, William; Hirsch, Lawrence J; Berg, Anne T; Blumenfeld, Hal

    2015-11-01

    The aim of our study was to evaluate the role of auras in preventing motor vehicle accidents (MVAs) among patients with medically refractory epilepsy. The Multicenter Study of Epilepsy Surgery database was used to perform a case-control study by identifying patients who had seizures while driving that led to MVAs (cases) and those who had seizures while driving without MVAs (controls). We compared presence of reliable auras and other aura-related features between the two groups. Two hundred fifteen of 553 patients reported having seizure(s) while driving; 74 were identified as "controls" and 141 as "cases." The two groups had similar demographic and clinical features. The presence of reliable auras was not different between the two groups (67% in cases vs. 65% in controls; odds ratio [OR] 0.89, 95% confidence interval [CI] 0.49-1.61, p = 0.76). In addition, the groups did not differ in the proportion of patients who reported longer (>1 min) auras (OR 0.7, 95% CI 0.28-1.76, p = 0.47), or who thought that their auras were of sufficient duration to be protective (OR 1.19, 95% CI 0.62-2.00, p = 0.77). Our study questions the long-held belief of a protective role of reliable auras against MVAs in people with epilepsy.

  17. Abnormal Connectivity Within Executive Resting-State Network in Migraine With Aura.

    Science.gov (United States)

    Tessitore, Alessandro; Russo, Antonio; Conte, Francesca; Giordano, Alfonso; De Stefano, Manuela; Lavorgna, Luigi; Corbo, Daniele; Caiazzo, Giuseppina; Esposito, Fabrizio; Tedeschi, Gioacchino

    2015-06-01

    To evaluate the executive control network connectivity integrity in patients with migraine with aura, in the interictal period, in comparison to patients with migraine without aura and healthy controls. Using resting-state functional magnetic resonance imaging, we compared executive control network functional connectivity in 20 patients with migraine with aura vs 20 sex and age-matched patients with migraine without aura and 20 healthy controls, and assessed the correlation between executive control network functional connectivity and clinical features of patients with migraine. We used voxel-based morphometry and diffusion tensor imaging to investigate potential structural or microstructural changes. Neuropsychological data revealed no significant executive dysfunction in patients with migraine. Resting-state functional magnetic resonance imaging showed significant group differences in right middle frontal gyrus (Talairach coordinates x, y, z: +26, +2, +48) and dorsal anterior cingulate cortex (Talairach coordinates x, y, z: +6, +13, +49), indicating that these areas had a decreased component activity in both patients with migraine with and without aura when compared with healthy controls. Conversely, there were no significant differences in the executive control network functional connectivity between patients with migraine with and without aura (P aura, in the interictal period. Although this functional phenomenon is present in the absence of clinically relevant executive deficits, it may reflect a vulnerability to executive high-demanding conditions of daily living activities in patients with migraine. © 2015 American Headache Society.

  18. Emissions of organic trace gases from savanna fires in southern Africa during the 1992 Southern African Fire Atmosphere Research Initiative and their impact on the formation of tropospheric ozone

    Science.gov (United States)

    Koppmann, R.; Khedim, A.; Rudolph, J.; Poppe, D.; Andreae, M. O.; Helas, G.; Welling, M.; Zenker, T.

    1997-08-01

    CO, CH4, and organic trace gases were measured in air samples collected during several flights with a DC-3 aircraft through the plumes from savanna fires and agricultural fires during the SAFARI 92 campaign in southern Africa in September and October 1992. In all samples a variety of higher molecular weight organic compounds was found, most of which are very reactive. More than 70 of the roughly 140 major components present could be identified. Typically, mixing ratios of several hundred parts per billion carbon of organic compounds were measured inside the plumes, corresponding to an emission ratio of total organic carbon relative to CO2 of up to 1%. About 50% of these emissions were in the form of oxygenated and unsaturated compounds. The contributions of still unknown compounds to the total emission of organic compounds add up to another 20-30%. The observed emission ratios relative to CO2 show a considerable variation depending on the fuel type and the burning stages of the fire. The lowest value of the emission ratio of the sum of all identified organic compounds relative to CO2 was found for a sugar cane fire with (1.7±0.7)×10-3 (ppb C/ppb CO2). For a large savanna fire in Kruger National Park the ratio was (7.4±1.6)×10-3 (ppb C/ppb CO2). The highest value was (13.7±0.9)×10-3 (ppb C/ppb CO2) for an uncontrolled fire of mainly wood and shrub in the Drakensberg region. Results of model calculations show that in biomass-burning plumes, reactive organic compounds contribute significantly to the formation of ozone, especially during the initial phase of photochemical processing.

  19. On the impact of aircraft emitted NO{sub x} on upper troposphere photochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Wahner, A.; Rohrer, F.; Ehhalt, D.H. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Atmosphaerische Chemie

    1997-12-31

    The enhanced nitrogen oxide concentrations influence the photochemical production of ozone as well as the steady state concentrations of hydroxyl radicals, OH, in the upper troposphere. That increase is small compared to the impact of NO{sub x} from fossil fuel combustion on boundary layer ozone. A simple quasi 2-D model was used for the latitude band 40 deg - 50 deg N to analyze the reasons for that. The model includes a simplified CH{sub 4} - CO chemistry and the salient sources of upper tropospheric NO{sub x}, namely lightning, stratospheric input, aircraft emissions and fast upward transport of surface emissions. It is shown that the maximum of net O{sub 3} production and OH concentrations occur at much lower NO{sub x} mixing ratios than in the lower troposphere. (author)

  20. The Impact of ENSO on Trace Gas Composition in the Upper Troposphere to Lower Stratosphere

    Science.gov (United States)

    Oman, Luke; Douglass, Anne; Ziemke, Jerald; Waugh, Darryn

    2016-04-01

    The El Nino-Southern Oscillation (ENSO) is the dominant mode of interannual variability in the tropical troposphere and its effects extend well into the stratosphere. Its impact on atmospheric dynamics and chemistry cause important changes to trace gas constituent distributions. A comprehensive suite of satellite observations, reanalyses, and chemistry climate model simulations are illuminating our understanding of processes like ENSO. Analyses of more than a decade of observations from NASA's Aura and Aqua satellites, combined with simulations from the Goddard Earth Observing System Chemistry-Climate Model (GEOSCCM) and other Chemistry Climate Modeling Initiative (CCMI) models, and the Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2) reanalysis have provided key insights into the response of atmospheric composition to ENSO. While we will primarily focus on ozone and water vapor responses in the upper troposphere to lower stratosphere, the effects of ENSO ripple through many important trace gas species throughout the atmosphere. The very large 2015-2016 El Nino event provides an opportunity to closely examine these impacts with unprecedented observational breadth. An improved quantification of natural climate variations, like those from ENSO, is needed to detect and quantify anthropogenic climate changes.

  1. Balloon-borne cryogenic frost-point hygrometer observations of water vapour in the tropical upper troposphere and lower stratosphere over India: First results

    Science.gov (United States)

    Sunilkumar, S. V.; Muhsin, M.; Emmanuel, Maria; Ramkumar, Geetha; Rajeev, K.; Sijikumar, S.

    2016-03-01

    Balloon-borne cryogenic frost-point hygrometer (CFH) observations of water vapour in the upper troposphere and lower stratosphere (UTLS) region carried out over India, from Trivandrum [8.5°N, 76.9°E] and Hyderabad [17.5°N, 78.6°E], were compared with that obtained from quasi-collocated Aura-Microwave Limb Sounder (MLS) satellite observations. Comparisons show a small dry bias for MLS in the stratosphere. Saturated or super-saturation layers observed near the base of tropical tropopause layer (TTL) are consistent with the quasi-collocated space-based observations of tropical cirrus from KALPANA-1 and CALIPSO. Disturbance of large scale waves in the upper troposphere appears to modulate the water vapour and cirrus distribution.

  2. Walter Benjamin's concept of aura and the cultural industry

    Directory of Open Access Journals (Sweden)

    Bráulio Santos Rabelo de Araújo

    2010-12-01

    Full Text Available Trata-se de uma análise do texto A obra de arte na era da reprodutibilidade técnica, de 1935, de Walter Benjamin, no qual o autor analisa as alterações provocadas pelas novas técnicas de produção artística na esfera da cultura, e desenvolve, como elemento principal, a tese de a reprodutibilidade técnica provocar a superação da aura pela obra de arte. Tendo como apoio o contraste do texto de Benjamin com o texto A indústria cultural: O esclarecimento como mistificação das massas, de Theodor Adorno e Max Horkheimer, de 1947, e a observação da produção do cinema, da música e do livro (artes necessariamente reprodutíveis, este artigo (a analisa a tese da superação do conceito de aura pela obra de arte na era da reprodutibilidade técnica, (b contrasta essa tese com a reflexão sobre indústria cultural de Adorno e Horkheimer e com as características da obra de arte produzida no decorrer do século 20 e início do século 21, e (c apresenta as contribuições que podem ser retiradas dessa análise para a atual reflexão a respeito dos impactos da Internet e das tecnologias digitais sobre a produção cultural contemporânea. Como resultado principal e do qual decorre outras conclusões, o artigo considera que as técnicas analisadas por Benjamin, apesar de terem tornado a obra de arte independente de um substrato único, não a emanciparam de seu caráter aurático. Os elementos centrais da aura (autenticidade e unicidade não foram superados, mas, ao contrário, adaptaram-se às mudanças técnicas, adaptação essa que ocorreu em torno da industrialização, a qual marcou a produção cultural no século 20.

  3. Impacts of land use and land cover changes on biogenic emissions of volatile organic compounds in China from the late 1980s to the mid-2000s: implications for tropospheric ozone and secondary organic aerosol

    Directory of Open Access Journals (Sweden)

    Yu Fu

    2014-11-01

    Full Text Available Based on the MEGAN (Model of Emissions of Gases and Aerosols from Nature module embedded within the global chemical transport model (GEOS-Chem, we estimate the changes in emissions of biogenic volatile organic compounds (BVOCs and their impacts on surface-layer O3 and secondary organic aerosols (SOA in China between the late 1980s and the mid-2000s by using the land cover dataset derived from remote sensing images and land use survey. The land cover change in China from the late 1980s to the mid-2000s can be characterised by an expansion of urban areas (the total urban area in the mid-2000s was four times that in the late 1980s and a reduction in total vegetation coverage by 4%. Regionally, the fractions of land covered by forests exhibited increases in southeastern and northeastern China by 10–30 and 5–15%, respectively, those covered by cropland decreased in most regions except that the farming–pastoral zone in northern China increased by 5–20%, and the factions of grassland in northern China showed a large reduction of 5–30%. With changes in both land cover and meteorological fields, annual BVOC emission in China is estimated to increase by 11.4% in the mid-2000s relative to the late 1980s. With anthropogenic emissions of O3 precursors, aerosol precursors and aerosols fixed at year 2005 levels, the changes in land cover and meteorological parameters from the late 1980s to the mid-2000s are simulated to change the seasonal mean surface-layer O3 concentrations by −4 to +6 ppbv (−10 to +20% and to change the seasonal mean surface-layer SOA concentrations by −0.4 to +0.6 µg m−3 (−20 to +30% over China. We find that the decadal changes in meteorological parameters had larger collective effects on BVOC emissions and surface-layer concentrations of O3 and SOA than those in land cover and land use alone. We also perform a sensitivity simulation to compare the impacts of changes in anthropogenic emissions on concentrations of O3

  4. Gaseous abundances and methane supersaturation in Titan's troposphere

    Science.gov (United States)

    Samuelson, Robert E.; Nath, Nitya R.; Borysow, Aleksandra

    1997-01-01

    Various properties of Titan's troposphere are inferred from an analysis of Voyager I infrared spectrometer (IRIS) data between 200 and 600/ cm. Two homogeneous spectral averages acquired at widely separated emission angles are chosen for the analysis. Both data sets are associated with northern low latitudes very close to that of the radio science ingress occultation point. Solutions require simultaneous nonlinear least-squares fits to the two IRIS data sets, coupled with iteration of the radio occultation refractivity data. Values and associated 1-sigma uncertainties of several parameters are inferred from our analysis. These include mole fractions for molecular hydrogen (approx. 0.0011), argon (small), and methane near the surface ( approx. 0.057). Solutions are also obtained for the hydrogen parafraction (close to equilibrium, with considerable uncertainty), air temperature near the surface ( approx. 93 K), surface surface temperature discontinuity (approx. 1 K), and maximum degree of methane supersaturation in the upper troposphere (approx. 1.5). Actual values for the above-mentioned parameters depend on the amount of ethane cloud near the tropopause. There is no evidence for methane clouds in the upper troposphere, nor is their presence compatible with large degrees of supersaturation. A wave number dependence for the stratospheric haze opacity is inferred similar to that found for a polymeric residue created in laboratory discharge experiments. This haze appears to be uniformly distributed with latitude between altitudes of 40 and 160 km, provided those nighttime data at southern high latitudes that are discounted.

  5. Homepage for the Global Tropospheric Experiment

    Science.gov (United States)

    Ward, Eugene

    1995-01-01

    The objective of my NASA summer research project was to create a homepage to describe and present results from the NASA Global Tropospheric Experiment (GTE). The GTE is a major component of NASA's Tropospheric Chemistry Program and is managed in the Atmospheric Studies Branch, Atmospheric Sciences Division at the NASA Langley Research Center.

  6. Performance Evaluation of Blind Tropospheric Delay correction ...

    African Journals Online (AJOL)

    lekky

    with accurate International GNSS Service (IGS)-tropospheric estimations for fifteen IGS stations over a period of 1 year on the Africa continent. ... Tropospheric delay is one of the main error sources in the analysis of space geodetic techniques ...

  7. Impact of climate change on tropospheric ozone and its global budgets

    Directory of Open Access Journals (Sweden)

    G. Zeng

    2008-01-01

    Full Text Available We present the chemistry-climate model UMCAM in which a relatively detailed tropospheric chemical module has been incorporated into the UK Met Office's Unified Model version 4.5. We obtain good agreements between the modelled ozone/nitrogen species and a range of observations including surface ozone measurements, ozone sonde data, and some aircraft campaigns.

    Four 2100 calculations assess model responses to projected changes of anthropogenic emissions (SRES A2, climate change (due to doubling CO2, and idealised climate change-associated changes in biogenic emissions (i.e. 50% increase of isoprene emission and doubling emissions of soil-NOx. The global tropospheric ozone burden increases significantly for all the 2100 A2 simulations, with the largest response caused by the increase of anthropogenic emissions. Climate change has diverse impacts on O3 and its budgets through changes in circulation and meteorological variables. Increased water vapour causes a substantial ozone reduction especially in the tropical lower troposphere (>10 ppbv reduction over the tropical ocean. On the other hand, an enhanced stratosphere-troposphere exchange of ozone, which increases by 80% due to doubling CO2, contributes to ozone increases in the extratropical free troposphere which subsequently propagate to the surface. Projected higher temperatures favour ozone chemical production and PAN decomposition which lead to high surface ozone levels in certain regions. Enhanced convection transports ozone precursors more rapidly out of the boundary layer resulting in an increase of ozone production in the free troposphere. Lightning-produced NOx increases by about 22% in the doubled CO2 climate and contributes to ozone production.

    The response to the increase of isoprene emissions shows that the change of ozone is largely determined by background NOx levels: high

  8. Impact of climate change on tropospheric ozone and its global budgets

    Directory of Open Access Journals (Sweden)

    G. Zeng

    2007-07-01

    Full Text Available We present the chemistry-climate model UM_CAM in which a relatively detailed tropospheric chemical module has been incorporated into the UK Met Office's Unified Model version 4.5. We obtain good agreements between the modelled ozone/nitrogen species and a range of observations including surface ozone measurements, ozone sonde data, and some aircraft campaigns.

    Four 2100 calculations assess model responses to projected changes of anthropogenic emissions (SRES A2, climate change (due to doubling CO2, and idealised climate change associated changes in biogenic emissions (i.e. 50% increase of isoprene emission and doubling emissions of soil-NOx. The global tropospheric ozone burden increases significantly for all the 2100 A2 simulations, with the largest response caused by the increase of anthropogenic emissions. Climate change has diverse impacts on O3 and its budgets through changes in circulation and meteorological variables. Increased water vapour causes a substantial ozone reduction especially in the tropical lower troposphere (>10 ppbv reduction over the tropical ocean. On the other hand, an enhanced stratosphere-troposphere exchange of ozone, which increases by 80% due to doubling CO2, contributes to ozone increases in the extratropical free troposphere which subsequently propagate to the surface. Projected higher temperatures favour ozone chemical production and PAN decomposition which lead to high surface ozone levels in certain regions. Enhanced convection transports ozone precursors more rapidly out of the boundary layer resulting in an increase of ozone production in the free troposphere. Lightning-produced NOx increases by about 22% in the doubled CO2 climate and contributes to ozone production.

    The response to the increase of isoprene emissions shows that the change of ozone is largely determined by background NOx levels: high NO

  9. Drivers of the tropospheric ozone budget throughout the 21st century under the medium-high climate scenario RCP 6.0

    Directory of Open Access Journals (Sweden)

    L. E. Revell

    2015-01-01

    Full Text Available Because tropospheric ozone is both a~greenhouse gas and harmful air pollutant, it is important to understand how anthropogenic activities may influence its abundance and distribution through the 21st century. Here, we present model simulations performed with the chemistry-climate model SOCOL, in which spatially disaggregated chemistry and transport tracers have been implemented in order to better understand the distribution and projected changes in tropospheric ozone. We examine the influences of ozone precursor emissions (nitrogen oxides (NOx, carbon monoxide (CO and volatile organic compounds (VOCs, climate change and stratospheric ozone recovery on the tropospheric ozone budget, in a~simulation following the climate scenario Representative Concentration Pathway (RCP 6.0. Changes in ozone precursor emissions have the largest effect, leading to a global-mean increase in tropospheric ozone which maximises in the early 21st century at 23%. The increase is most pronounced at northern midlatitudes, due to regional emission patterns: between 1990 and 2060, northern midlatitude tropospheric ozone remains at constantly large abundances: 31% larger than in 1960. Over this 70 year period, attempts to reduce emissions in Europe and North America do not have an effect on zonally-averaged northern midlatitude ozone because of increasing emissions from Asia, together with the longevity of ozone in the troposphere. A~simulation with fixed anthropogenic ozone precursor emissions of NOx, CO and non-methane VOCs at 1960 conditions shows a 6 % increase in global-mean tropospheric ozone, and an 11% increase at northern midlatitudes. This increase maximises in the 2080s, and is mostly caused by methane, which maximises in the 2080s following RCP 6.0, and plays an important role in controlling ozone directly, and indirectly through its influence on other VOCs and CO. Enhanced flux of ozone from the stratosphere to the troposphere as well as climate change

  10. Climate change, tropospheric ozone and particulate matter, and health impacts.

    Science.gov (United States)

    Ebi, Kristie L; McGregor, Glenn

    2008-11-01

    Because the state of the atmosphere determines the development, transport, dispersion, and deposition of air pollutants, there is concern that climate change could affect morbidity and mortality associated with elevated concentrations of these gases and fine particles. We review how climate change could affect future concentrations of tropospheric ozone and particulate matter (PM), and what changing concentrations could mean for population health. We review studies projecting the impacts of climate change on air quality and studies projecting the impacts of these changes on morbidity and mortality. Climate change could affect local to regional air quality through changes in chemical reaction rates, boundary layer heights that affect vertical mixing of pollutants, and changes in synoptic airflow patterns that govern pollutant transport. Sources of uncertainty include the degree of future climate change, future emissions of air pollutants and their precursors, and how population vulnerability may change in the future. Given these uncertainties, projections suggest that climate change will increase concentrations of tropospheric ozone, at least in high-income countries when precursor emissions are held constant, which would increase morbidity and mortality. Few projections are available for low- and middle-income countries. The evidence is less robust for PM, primarily because few studies have been conducted. Additional research is needed to better understand the possible impacts of climate change on air pollution-related health impacts. If improved models continue to project higher ozone concentrations with climate change, then reducing greenhouse gas emissions would enhance the health of current and future generations.

  11. Next Generation Aura-OMI SO2 Retrieval Algorithm: Introduction and Implementation Status

    Science.gov (United States)

    Li, Can; Joiner, Joanna; Krotkov, Nickolay A.; Bhartia, Pawan K.

    2014-01-01

    We introduce our next generation algorithm to retrieve SO2 using radiance measurements from the Aura Ozone Monitoring Instrument (OMI). We employ a principal component analysis technique to analyze OMI radiance spectral in 310.5-340 nm acquired over regions with no significant SO2. The resulting principal components (PCs) capture radiance variability caused by both physical processes (e.g., Rayleigh and Raman scattering, and ozone absorption) and measurement artifacts, enabling us to account for these various interferences in SO2 retrievals. By fitting these PCs along with SO2 Jacobians calculated with a radiative transfer model to OMI-measured radiance spectra, we directly estimate SO2 vertical column density in one step. As compared with the previous generation operational OMSO2 PBL (Planetary Boundary Layer) SO2 product, our new algorithm greatly reduces unphysical biases and decreases the noise by a factor of two, providing greater sensitivity to anthropogenic emissions. The new algorithm is fast, eliminates the need for instrument-specific radiance correction schemes, and can be easily adapted to other sensors. These attributes make it a promising technique for producing long-term, consistent SO2 records for air quality and climate research. We have operationally implemented this new algorithm on OMI SIPS for producing the new generation standard OMI SO2 products.

  12. Dipyridamole may induce migraine in patients with migraine without aura

    DEFF Research Database (Denmark)

    Kruuse, C; Lassen, L H; Iversen, Helle Klingenberg

    2006-01-01

    Dipyridamole inhibits phosphodiesterase 5 (PDE5) and adenosine re-uptake. The most prominent side-effect is headache. We examined the migraine-generating effects of dipyridamole as well as the cerebral blood velocity response in a single-blind study, including 10 patients with migraine without aura...... and 10 healthy subjects. Dipyridamole 0.142 mg/kg per min was administered intravenously. Headache intensity was scored on a verbal rating scale along with pain characteristics and accompanying symptoms. Blood velocity in the middle cerebral artery (V(mca)), blood pressure and heart rate were recorded...... of dipyridamole on the cGMP signalling pathway as well as a possible bidirectional effect of adenosine on migraine induction....

  13. Experimental lead poisoning in Turkey Vultures, Cathartes aura

    Science.gov (United States)

    Carpenter, J.W.; Pattee, O.H.; Fritts, S.H.; Rattner, B.A.; Wiemeyer, Stanley N.; Royle, J. Andrew; Smith, M.R.

    2003-01-01

    Lead-induced mortality appears to have been a major factor in the decline of the California condor, Gymnogyps californianus. We orally dosed turkey vultures (Cathartes aura) with BB-sized lead shot from January 1988 through July 1988 to determine physiological response (delta-aminolevulinic acid dehydratase inhibition, erythrocyte protoporphyrin levels, anemia), diagnostic tissue lead concentrations (blood, liver, and kidney), and comparative sensitivity of this species. Two turkey vultures died and two became so intoxicated they were euthanized. Overall, responses of measured parameters were comparable to other species exposed to lead although there was considerable individual variation. Survival time (143-211 days), even with the large number of shot and constant redosing, was much longer than reported for other species of birds, suggesting considerable tolerance by turkey vultures to the deleterious effects of lead ingestion. Based on these observations, turkey vultures appear to be poor models for assessing the risk of lead poisoning to California condors or predicting their physiological response.

  14. Direct Observations of PMC Local Time Variations by Aura OMI

    Science.gov (United States)

    DeLand, Matthew T.; Shettle, Eric P.; Thomas, Gary E.; Olivero, John J.

    2010-01-01

    The Ozone Monitoring Instrument (OMI) on the Aura satellite obtains unique measurements for polar mesospheric cloud (PMC) analysis. Its wide cross-track viewing swath and high along-track spatial resolution makes it possible to directly evaluate PMC occurrence frequency and brightness variations between 6S" and 8S' latitude as a function of local time over a 12-14 h continuous period. OMI PMC local time variations are closely coupled to concurrent variations in measurement scattering angle, so that ice phase function effects must be considered when interpreting the observations. Two different phase functions corresponding to bright and faint clouds are examined in this analysis. OMI observations show maximum frequency and albedo values at 8-10 h local time in the Northern Hemisphere, with decreasing amplitude at higher latitudes. Southern Hemisphere values reach a minimum at 18-20 h LT. Larger variations are seen in Northern Hemisphere data. No statistically significant longitudinal dependence was seen.

  15. Summary of Aqua, Aura, and Terra High Interest Events

    Science.gov (United States)

    Newman, Lauri

    2015-01-01

    Single-obs tracking Sparsely tracked objects are an unfortunate reality of CARA operations Terra vs. 32081: new track with bad data was included in OD solution for secondary object and risk became high CARA and JSpOC discussed tracking and OSAs threw out the bad data. Event no longer presented high risk based on new OD Improvement: CARA now sends JSpOC a flag indicating when a single obs is included, so OSAs can evaluate if manual update to OD is required. Missing ASW OCMsAura vs. 87178, TCA: 317 at 08:04 UTC. Post-maneuver risk (conjunction was identified in OO results)CARA confirmed with JSpOC that ASW OCMs should have been received in addition to OO OCMsJSpOC corrected the manual error in their script that prevented the data from being delivered to CARAJSpOC QAd their other scripts to ensure this error did not exist in other places.

  16. Direct Observations of PMC Local Time Variations by Aura OMI

    Science.gov (United States)

    DeLand, Matthew T.; Shettle, Eric P.; Thomas, Gary E.; Olivero, John J.

    2010-01-01

    The Ozone Monitoring Instrument (OMI) on the Aura satellite obtains unique measurements for polar mesospheric cloud (PMC) analysis. Its wide cross-track viewing swath and high along-track spatial resolution makes it possible to directly evaluate PMC occurrence frequency and brightness variations between 6S" and 8S' latitude as a function of local time over a 12-14 h continuous period. OMI PMC local time variations are closely coupled to concurrent variations in measurement scattering angle, so that ice phase function effects must be considered when interpreting the observations. Two different phase functions corresponding to bright and faint clouds are examined in this analysis. OMI observations show maximum frequency and albedo values at 8-10 h local time in the Northern Hemisphere, with decreasing amplitude at higher latitudes. Southern Hemisphere values reach a minimum at 18-20 h LT. Larger variations are seen in Northern Hemisphere data. No statistically significant longitudinal dependence was seen.

  17. Site Protection Efforts at the AURA Observatory in Chile

    Science.gov (United States)

    Smith, R. Chris; Sanhueza, Pedro; Smith, Malcolm G.

    2016-10-01

    The AURA Observatory site in northern Chile, which includes Cerro Tololo and Cerro Pachon, has been operational for over 50 years now, facing a variety of challenges to its long-term future. The site now hosts over 20 operational telescopes, ranging from small projects with 0.4m telescopes to the Blanco 4m, the SOAR 4.1m, and the 8m Gemini-South telescopes. In addition, we have recently begun the construction of the Large Synoptic Survey Telescope (LSST) on the summit of Cerro Pachon. We summarize our efforts over the past 20-30 years to highlight the importance of site protection through education and public outreach as well as through more recent promotion of IDA certifications in the region and support for the World Heritage initiatives described by others in this conference.

  18. Magnetic resonance image abnormality in migraine with aura

    Energy Technology Data Exchange (ETDEWEB)

    Ziegler, D.K.; Batnitzky, S.; Barter, R.; McMillan, J.H. (Kansas Univ., Kansas City, KS (United States). Medical Center)

    1991-07-01

    Cerebral magnetic resonance imaging (MRI) was performed on 18 patients with migraine characterized by aura consisting of both visual symtoms and parasthesias. 15 headache-free individuals of the same age range were used as controls. Records were radomized and read in blind fashion by two neuroradiologists. Small subcortical white matter lesions were seen in three migraine cases and two controls. In one migraine case cortical infarctions were seen. In two controls, small areas of increased density similar to those in migraine were seen. No consistent correlation of migraine or its duration with cerebral atrophy was found. It is concluded that identification of both these MRI findings (small subcortical white lesions and cerebral atrophy) as significantly associated with migraine is doubtful. 21 refs., 2 figs.

  19. Validation of Aura Microwave Limb Sounder HCl Measurements

    Science.gov (United States)

    Froidevaux, L.; Jiang, Y. B.; Lambert, A.; Livesey, N. J.; Read, W. G.; Waters, J. W.; Fuller, R. A.; Marcy, T. P.; Popp, P. J.; Gao, R. S.; hide

    2008-01-01

    The Earth Observing System (EOS) Microwave Limb Sounder (MLS) aboard the Aura satellite has provided daily global HCl profiles since August 2004. We provide a characterization of the resolution, random and systematic uncertainties, and known issues for the version 2.2 MLS HCl data. The MLS sampling allows for comparisons with many (1500 to more than 3000) closely matched profiles from the Halogen Occultation Experiment (HALOE) and Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS). These data sets provide HCl latitudinal distributions that are, overall, very similar to those from (coincident) MLS profiles, although there are some discrepancies in the upper stratosphere between the MLS and HALOE gradients. As found in previous work, MLS and ACE HCl profiles agree very well (within approximately 5%, on average), but the MLS HCl abundances are generally larger (by 10-20%) than HALOE HCl. The bias versus HALOE is unlikely to arise mostly from MLS, as a similar systematic bias (of order 15%) is not observed between average MLS and balloon-borne measurements of HCl, obtained over Fort Sumner, New Mexico, in 2004 and 2005. At the largest pressure (147 hPa) for MLS HCl, a high bias (approximately 0.2 ppbv) is apparent in analyses of low to midlatitude data versus in situ aircraft chemical ionization mass spectrometry (CIMS) HCl measurements from the Aura Validation Experiment (AVE) campaigns in 2004, 2005, and 2006; this bias is also observed in comparisons of MLS and aircraftHCl/O3 correlations. Good agreement between MLS and CIMS HCl is obtained at 100 to 68 hPa. The recommended pressure range for MLS HCl is from 100 to 0.15 hPa.

  20. Validation of Aura Microwave Limb Sounder HCl Measurements

    Science.gov (United States)

    Froidevaux, L.; Jiang, Y. B.; Lambert, A.; Livesey, N. J.; Read, W. G.; Waters, J. W.; Fuller, R. A.; Marcy, T. P.; Popp, P. J.; Gao, R. S.; Fahey, D. W.; Jucks, K. W.; Stachnik, R. A.; Toon, G. C.; Christensen, L. E.; Webster, C. R.; Bernath, P. F.; Boone, C. D.; Walker, K. A.; Pumphrey, H. C.; Harwood, R. S.; Manney, G. L.; Schwartz, M. J.; Daffer, W. H.; Drouin, B. J.

    2008-01-01

    The Earth Observing System (EOS) Microwave Limb Sounder (MLS) aboard the Aura satellite has provided daily global HCl profiles since August 2004. We provide a characterization of the resolution, random and systematic uncertainties, and known issues for the version 2.2 MLS HCl data. The MLS sampling allows for comparisons with many (1500 to more than 3000) closely matched profiles from the Halogen Occultation Experiment (HALOE) and Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS). These data sets provide HCl latitudinal distributions that are, overall, very similar to those from (coincident) MLS profiles, although there are some discrepancies in the upper stratosphere between the MLS and HALOE gradients. As found in previous work, MLS and ACE HCl profiles agree very well (within approximately 5%, on average), but the MLS HCl abundances are generally larger (by 10-20%) than HALOE HCl. The bias versus HALOE is unlikely to arise mostly from MLS, as a similar systematic bias (of order 15%) is not observed between average MLS and balloon-borne measurements of HCl, obtained over Fort Sumner, New Mexico, in 2004 and 2005. At the largest pressure (147 hPa) for MLS HCl, a high bias (approximately 0.2 ppbv) is apparent in analyses of low to midlatitude data versus in situ aircraft chemical ionization mass spectrometry (CIMS) HCl measurements from the Aura Validation Experiment (AVE) campaigns in 2004, 2005, and 2006; this bias is also observed in comparisons of MLS and aircraftHCl/O3 correlations. Good agreement between MLS and CIMS HCl is obtained at 100 to 68 hPa. The recommended pressure range for MLS HCl is from 100 to 0.15 hPa.

  1. Changes in tropospheric composition and air quality due to stratospheric ozone depletion.

    Science.gov (United States)

    Solomon, Keith R; Tang, Xiaoyan; Wilson, Stephen R; Zanis, Prodromos; Bais, Alkiviadis F

    2003-01-01

    Increased UV-B through stratospheric ozone depletion leads to an increased chemical activity in the lower atmosphere (the troposphere). The effect of stratospheric ozone depletion on tropospheric ozone is small (though significant) compared to the ozone generated anthropogenically in areas already experiencing air pollution. Modeling and experimental studies suggest that the impacts of stratospheric ozone depletion on tropospheric ozone are different at different altitudes and for different chemical regimes. As a result the increase in ozone due to stratospheric ozone depletion may be greater in polluted regions. Attributable effects on concentrations are expected only in regions where local emissions make minor contributions. The vertical distribution of NOx (NO + NO2), the emission of volatile organic compounds and the abundance of water vapor, are important influencing factors. The long-term nature of stratospheric ozone depletion means that even a small increase in tropospheric ozone concentration can have a significant impact on human health and the environment. Trifluoroacetic acid (TFA) and chlorodifluoroacetic acid (CDFA) are produced by the atmospheric degradation of hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs). TFA has been measured in rain, rivers, lakes, and oceans, the ultimate sink for these and related compounds. Significant anthropogenic sources of TFA other than degradation HCFCs and HFCs have been identified. Toxicity tests under field conditions indicate that the concentrations of TFA and CDFA currently produced by the atmospheric degradation of HFCs and HCFCs do not present a risk to human health and the environment. The impact of the interaction between ozone depletion and future climate change is complex and a significant area of current research. For air quality and tropospheric composition, a range of physical parameters such as temperature, cloudiness and atmospheric transport will modify the impact of UV-B. Changes in the

  2. Recent Biomass Burning in the Tropics and Related Changes in Tropospheric Ozone

    Science.gov (United States)

    Ziemke; Chandra, J. R. S.; Duncan, B. N.; Schoeberl, M. R.; Torres, O.; Damon, M. R.; Bhartia, P. K.

    2009-01-01

    Biomass burning is an important source of chemical precursors of tropospheric ozone. In the tropics, biomass burning produces ozone enhancements over broad regions of Indonesia, Africa, and South America including Brazil. Fires are intentionally set in these regions during the dry season each year to clear cropland and to clear land for human/industrial expansion. In Indonesia enhanced burning occurs during dry El Nino conditions such as in 1997 and 2006. These burning activities cause enhancement in atmospheric particulates and trace gases which are harmful to human health. Measurements from the Aura Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) from October 2004-November 2008 are used to evaluate the effects of biomass burning on tropical tropospheric ozone. These measurements show sizeable decreases approx.15-20% in ozone in Brazil during 2008 compared to 2007 which we attribute to the reduction in biomass burning. Three broad biomass burning regions in the tropics (South America including Brazil, western Africa, and Indonesia) were analyzed in the context of OMI/MLS measurements and the Global Modeling Initiative (GMI) chemical transport model developed at Goddard Space Flight Center. The results indicate that the impact of biomass burning on ozone is significant within and near the burning regions with increases of approx.10-25% in tropospheric column ozone relative to average background concentrations. The model suggests that about half of the increases in ozone from these burning events come from altitudes below 3 km. Globally the model indicates increases of approx.4-5% in ozone, approx.7-9% in NO, (NO+NO2), and approx.30-40% in CO.

  3. Timing and topography of cerebral blood flow, aura, and headache during migraine attacks

    DEFF Research Database (Denmark)

    Olesen, J; Friberg, L; Olsen, T S

    1990-01-01

    and statistically significant spatial relations. The first observable event was a decrease of regional cerebral blood flow posteriorly in one cerebral hemisphere. Further development of this pathological process was accompanied by the aura symptoms. Thereafter headache occurred while regional cerebral blood flow...... remained decreased. During the headache phase, regional cerebral blood flow gradually changed from abnormally low to abnormally high without apparent change in headache. In some patients headache disappeared while regional cerebral blood flow remained increased. Although regional cerebral blood flow...... reduction and aura symptoms in the great majority of patients were unilateral, one-third had bilateral headache. Unilateral headache usually localized to the side on which regional cerebral blood flow was reduced and from which the aura symptoms originated (i.e., aura symptoms were perceived to occur...

  4. No abnormalities of intrinsic brain connectivity in the interictal phase of migraine with aura

    DEFF Research Database (Denmark)

    Hougaard, Anders; Amin, F M; Magon, S

    2015-01-01

    BACKGROUND AND PURPOSE: Functional neuroimaging studies have shown hyperresponsiveness of cortical areas to visual stimuli in migraine patients with aura outside of attacks. This may be a key feature in the initiation of aura episodes and possibly also migraine headache attacks. It is unknown...... if cortical dysfunction is present at rest, i.e. in the absence of any external stimuli. Functional magnetic resonance imaging is a powerful technique for evaluating resting state functional connectivity, i.e. coherence of brain activity across cerebral areas. The objective of this study was to investigate...... resting-state functional brain connectivity in migraineurs with aura outside of attacks using functional magnetic resonance imaging. METHODS: Forty patients suffering from migraine with visual aura and 40 individually age and gender matched healthy controls with no history or family history of migraine...

  5. HIRDLS/Aura Level 3 Chlorofluorocarbon-11 (CFC-11) Zonal Fourier Coefficients V007

    Data.gov (United States)

    National Aeronautics and Space Administration — The "HIRDLS/Aura Level 3 Chlorofluorocarbon-11 (CFC-11) Zonal Fourier Coefficients" version 7 data product (H3ZFCCFC11) contains the entire mission (~3 years) of...

  6. History of migraine with aura and cortical spreading depression from 1941 and onwards

    DEFF Research Database (Denmark)

    Tfelt-Hansen, P C

    2010-01-01

    visual cortex. Leão described cortical spreading depression (CSD) in rabbits in 1944 and noticed its similarity to the migraine aura. Despite these scattered pieces of evidence, the prevailing theory was that the migraine aura was caused by a vasospasm and cortical ischaemia. The advent of a technique...... borders of supply of major cerebral arteries. These observations refuted the ischaemic hypothesis. The human studies showed initial hyperaemia followed by prolonged hypoperfusion. The relation between aura and CSD was known to cause short-lasting, and therefore not obvious vasodilation...... expressed in mice and lower the threshold for CSD. The seminal papers on rCBF and CSD published in the 1980s caused a dramatic shift in our concepts of migraine aura. They moved attention from ischaemia to CSD and thereby to the brain itself, and paved the way for subsequent discoveries of brainstem...

  7. HIRDLS/Aura Level 3 Nitrogen Dioxide (NO2) Zonal Fourier Coefficients V007

    Data.gov (United States)

    National Aeronautics and Space Administration — The "HIRDLS/Aura Level 3 Nitrogen Dioxide (NO2) Zonal Fourier Coefficients" version 7 data product (H3ZFCNO2) contains the entire mission (~3 years) of HIRDLS data...

  8. Migraine with Aura or Sports-Related Concussion: Case Report, Pathophysiology, and Multidisciplinary Approach to Management.

    Science.gov (United States)

    Ellis, Michael J; Cordingley, Dean; Girardin, Richard; Ritchie, Lesley; Johnston, Janine

    The evaluation and management of athletes presenting with clinical features of migraine headache with aura in the setting of sports-related head trauma is challenging. We present a case report of a 15-yr-old boy with a history of migraine with visual aura that developed acute visual disturbance and headache after a head injury during an ice hockey game. The patient underwent comprehensive assessment at a multidisciplinary concussion program, including neuro-ophthalmological examination, neurocognitive testing, and graded aerobic treadmill testing. Clinical history and multidisciplinary assessment was consistent with the diagnosis of coexisting sports-related concussion and migraine with brainstem aura. The authors discuss the pearls and pitfalls of managing patients who develop migraine headache with visual aura after sports-related head injury and the value of a comprehensive multidisciplinary approach to this unique patient population.

  9. EOS Aura Mission Status at Earth Science Constellation MOWG Meeting @ LASP (Boulder, CO) April 13, 2016

    Science.gov (United States)

    Guit, William J.; Fisher, Dominic

    2016-01-01

    Presentation reflects EOS Aura mission status, spacecraft subsystems summary, recent and planned activities, inclination adjust maneuvers, propellant usage, orbit maintenance maneuvers, conjunction assessment events, orbital parameters trends and predictions.

  10. HIRDLS/Aura Level 3 Water Vapor (H2O) Zonal Fourier Coefficients V007

    Data.gov (United States)

    National Aeronautics and Space Administration — The "HIRDLS/Aura Level 3 Water Vapor (H2O) Zonal Fourier Coefficients" version 7 data product (H3ZFCH2O) contains the entire mission (~3 years) of HIRDLS data...

  11. HIRDLS/Aura Level 3 Geopotential Height Zonal Fourier Coefficients V007

    Data.gov (United States)

    National Aeronautics and Space Administration — The "HIRDLS/Aura Level 3 Geopotential Height Zonal Fourier Coefficients" version 7 data product (H3ZFCGPH) contains the entire mission (~3 years) of HIRDLS data...

  12. HIRDLS/Aura Level 3 Chlorofluorocarbon-12 (CFC-12) Zonal Fourier Coefficients V007

    Data.gov (United States)

    National Aeronautics and Space Administration — The "HIRDLS/Aura Level 3 Chlorofluorocarbon-12 (CFC-12) Zonal Fourier Coefficients" version 7 data product (H3ZFCCFC12) contains the entire mission (~3 years) of...

  13. HIRDLS/Aura Level 3 Dinitrogen Pentoxide (N2O5) Zonal Fourier Coefficients V007

    Data.gov (United States)

    National Aeronautics and Space Administration — The "HIRDLS/Aura Level 3 Dinitrogen Pentoxide (N2O5) Zonal Fourier Coefficients" version 7 data product (H3ZFCN2O) contains the entire mission (~3 years) of HIRDLS...

  14. HIRDLS/Aura Level 3 Extinction at 8.3 Microns Zonal Fourier Coefficients V007

    Data.gov (United States)

    National Aeronautics and Space Administration — The "HIRDLS/Aura Level 3 Extinction at 8.3 Microns Zonal Fourier Coefficients" version 7 data product (H3ZFC8MEXT) contains the entire mission (~3 years) of HIRDLS...

  15. HIRDLS/Aura Level 3 Nitric Acid (HNO3) Zonal Fourier Coefficients V007

    Data.gov (United States)

    National Aeronautics and Space Administration — The "HIRDLS/Aura Level 3 Nitric Acid (HNO3) Zonal Fourier Coefficients" version 7 data product (H3ZFCHNO3) contains the entire mission (~3 years) of HIRDLS data...

  16. Jet characterization in the upper troposphere/lower stratosphere (UTLS: applications to climatology and transport studies

    Directory of Open Access Journals (Sweden)

    G. L. Manney

    2011-06-01

    Full Text Available A method of classifying the upper tropospheric/lower stratospheric (UTLS jets has been developed that allows satellite and aircraft trace gas data and meteorological fields to be efficiently mapped in a jet coordinate view. A detailed characterization of multiple tropopauses accompanies the jet characterization. Jet climatologies show the well-known high altitude subtropical and lower altitude polar jets in the upper troposphere, as well as a pattern of concentric polar and subtropical jets in the Southern Hemisphere, and shifts of the primary jet to high latitudes associated with blocking ridges in Northern Hemisphere winter. The jet-coordinate view segregates air masses differently than the commonly-used equivalent latitude (EqL coordinate throughout the lowermost stratosphere and in the upper troposphere. Mapping O3 data from the Aura Microwave Limb Sounder (MLS satellite and the Winter Storms aircraft datasets in jet coordinates thus emphasizes different aspects of the circulation compared to an EqL-coordinate framework: the jet coordinate reorders the data geometrically, thus highlighting the strong PV, tropopause height and trace gas gradients across the subtropical jet, whereas EqL is a dynamical coordinate that may blur these spatial relationships but provides information on irreversible transport. The jet coordinate view identifies the concentration of stratospheric ozone well below the tropopause in the region poleward of and below the jet core, as well as other transport features associated with the upper tropospheric jets. Using the jet information in EqL coordinates allows us to study trace gas distributions in regions of weak versus strong jets, and demonstrates weaker transport barriers in regions with less jet influence. MLS and Atmospheric Chemistry Experiment-Fourier Transform Spectrometer trace gas fields for spring 2008 in jet coordinates show very strong, closely correlated, PV, tropopause height and trace gas

  17. Factors controlling variability in the oxidative capacity of the troposphere since the Last Glacial Maximum

    Directory of Open Access Journals (Sweden)

    L. T. Murray

    2013-09-01

    Full Text Available The oxidative capacity of past atmospheres is highly uncertain. We present here a new climate-biosphere-chemistry modeling framework to determine oxidant levels in the present and past troposphere. We use the GEOS-Chem chemical transport model driven by meteorological fields from the NASA Goddard Institute of Space Studies (GISS ModelE, with land cover and fire emissions from dynamic global vegetation models. We present time-slice simulations for the present day, late preindustrial (AD 1770, and the Last Glacial Maximum (LGM; 19–23 ka, and we test the sensitivity of model results to uncertainty in lightning and fire emissions. We find that most preindustrial and paleo climate simulations yield reduced oxidant levels relative to the present day. Contrary to prior studies, tropospheric mean OH in our ensemble shows little change at the LGM relative to the preindustrial (0.5 ± 12%, despite large reductions in methane concentrations. We find a simple linear relationship between tropospheric mean ozone photolysis rates, water vapor, and total emissions of NOx and reactive carbon that explains 72% of the variability in global mean OH in 11 different simulations across the last glacial-interglacial time interval and the Industrial Era. Key parameters controlling the tropospheric oxidative capacity over glacial-interglacial periods include overhead stratospheric ozone, tropospheric water vapor, and lightning NOx emissions. Variability in global mean OH since the LGM is insensitive to fire emissions. Our simulations are broadly consistent with ice-core records of Δ17O in sulfate and nitrate at the LGM, and CO, HCHO, and H2O2 in the preindustrial. Our results imply that the glacial-interglacial changes in atmospheric methane observed in ice cores are predominantly driven by changes in its sources as opposed to its sink with OH.

  18. Cardiovascular Risk Factors and Migraine without Aura: A case-control Study

    Directory of Open Access Journals (Sweden)

    Azadeh Sadatnaseri

    2013-07-01

    Full Text Available Background: Migraine with aura (MA has been identified as a risk factor for cardiovascular disease. Previous observation has also found higher prevalence of cardiovascular risk factors in migraineurs without aura (MO, but the results have been conflicting. The present study was conducted to assess the association between cardiovascular risk factors and migraine without aura among Iranians.Methods: In our study the prevalence of cardiovascular risk factors, including hypertension, hyperglycemia, dyslipidemia, obesity, cigarette smoking, and family history of early coronary artery disease, were studied in347 migraineurs without aura and 267 non-migraineurs. The odds ratio (ORs with 95% confidence interval (95% CI was used to assess the strength of the association.Results: Patients with migraine without aura were at an increased risk of developing hypertension (ORadj = 1.9;P = 0.029, but there was no difference in other cardiovascular risk profiles, including hyperglycemia, dyslipidemia, obesity, cigarette smoking, and family history of early coronary artery disease.Conclusion: Our study revealed that the prevalence of hypertension was higher in migraineurs without aura in comparison with non-migraineurs. Therefore, physicians are supposed to be more vigilant in examining these patients and take care not to prescribe medications that may provoke hypertension.

  19. Multi-instrument gravity-wave measurements over Tierra del Fuego and the Drake Passage - Part 1: Potential energies and vertical wavelengths from AIRS, COSMIC, HIRDLS, MLS-Aura, SAAMER, SABER and radiosondes

    Science.gov (United States)

    Wright, Corwin J.; Hindley, Neil P.; Moss, Andrew C.; Mitchell, Nicholas J.

    2016-03-01

    Gravity waves in the terrestrial atmosphere are a vital geophysical process, acting to transport energy and momentum on a wide range of scales and to couple the various atmospheric layers. Despite the importance of these waves, the many studies to date have often exhibited very dissimilar results, and it remains unclear whether these differences are primarily instrumental or methodological. Here, we address this problem by comparing observations made by a diverse range of the most widely used gravity-wave-resolving instruments in a common geographic region around the southern Andes and Drake Passage, an area known to exhibit strong wave activity. Specifically, we use data from three limb-sounding radiometers (Microwave Limb Sounder, MLS-Aura; HIgh Resolution Dynamics Limb Sounder, HIRDLS; Sounding of the Atmosphere using Broadband Emission Radiometry, SABER), the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) GPS-RO constellation, a ground-based meteor radar, the Advanced Infrared Sounder (AIRS) infrared nadir sounder and radiosondes to examine the gravity wave potential energy (GWPE) and vertical wavelengths (λz) of individual gravity-wave packets from the lower troposphere to the edge of the lower thermosphere ( ˜ 100 km). Our results show important similarities and differences. Limb sounder measurements show high intercorrelation, typically > 0.80 between any instrument pair. Meteor radar observations agree in form with the limb sounders, despite vast technical differences. AIRS and radiosonde observations tend to be uncorrelated or anticorrelated with the other data sets, suggesting very different behaviour of the wave field in the different spectral regimes accessed by each instrument. Evidence of wave dissipation is seen, and varies strongly with season. Observed GWPE for individual wave packets exhibits a log-normal distribution, with short-timescale intermittency dominating over a well-repeated monthly-median seasonal

  20. An Analysis of the Concept "Aura" in Benjamin's Literature Criticism%对本雅明文艺批评中"Aura"概念的梳理

    Institute of Scientific and Technical Information of China (English)

    朱洪举

    2004-01-01

    "Aura"在本雅明的文艺批评中是一个非常重要的概念,本文采取文本细读的方式,对有关此概念的论述进行梳理,以对"Aura"进行多层次的界定,并以此作为契入点,来考察本雅明对现代艺术和古典艺术的看法.

  1. Aura OMI observations of regional SO2 and NO2 pollution changes from 2005 to 2014

    Directory of Open Access Journals (Sweden)

    N. A. Krotkov

    2015-10-01

    Full Text Available The Ozone Monitoring Instrument (OMI onboard NASA's Aura satellite has been providing global observations of the ozone layer and key atmospheric pollutant gases, such as nitrogen dioxide (NO2 and sulfur dioxide (SO2, since October 2004. The data products from the same instrument provide consistent spatial and temporal coverage and permit the study of anthropogenic and natural emissions on local-to-global scales. In this paper we examine changes in SO2 and NO2 over some of the world's most polluted industrialized regions during the first decade of OMI observations. In terms of regional pollution changes, we see both upward and downward trends, sometimes in opposite directions for NO2 and SO2, for the different study areas. The trends are, for the most part, associated with economic and/or technological changes in energy use, as well as regional regulatory policies. Over the eastern US, both NO2 and SO2 levels decreased dramatically from 2005 to 2014, by more than 40 and 80 %, respectively, as a result of both technological improvements and stricter regulations of emissions. OMI confirmed large reductions in SO2 over eastern Europe's largest coal power plants after installation of flue gas desulfurization devices. The North China Plain has the world's most severe SO2 pollution, but a decreasing trend has been observed since 2011, with about a 50 % reduction in 2012–2014, due to an economic slowdown and government efforts to restrain emissions from the power and industrial sectors. In contrast, India's SO2 and NO2 levels from coal power plants and smelters are growing at a fast pace, increasing by more than 100 and 50 %, respectively, from 2005 to 2014. Several SO2 hot spots observed over the Persian Gulf are probably related to oil and gas operations and indicate a possible underestimation of emissions from these sources in bottom-up emission inventories. Overall, OMI observations have proved to be very valuable in documenting rapid changes in

  2. Aura OMI observations of regional SO2 and NO2 pollution changes from 2005 to 2015

    Science.gov (United States)

    Krotkov, Nickolay A.; McLinden, Chris A.; Li, Can; Lamsal, Lok N.; Celarier, Edward A.; Marchenko, Sergey V.; Swartz, William H.; Bucsela, Eric J.; Joiner, Joanna; Duncan, Bryan N.; Folkert Boersma, K.; Pepijn Veefkind, J.; Levelt, Pieternel F.; Fioletov, Vitali E.; Dickerson, Russell R.; He, Hao; Lu, Zifeng; Streets, David G.

    2016-04-01

    The Ozone Monitoring Instrument (OMI) onboard NASA's Aura satellite has been providing global observations of the ozone layer and key atmospheric pollutant gases, such as nitrogen dioxide (NO2) and sulfur dioxide (SO2), since October 2004. The data products from the same instrument provide consistent spatial and temporal coverage and permit the study of anthropogenic and natural emissions on local-to-global scales. In this paper, we examine changes in SO2 and NO2 over some of the world's most polluted industrialized regions during the first decade of OMI observations. In terms of regional pollution changes, we see both upward and downward trends, sometimes in opposite directions for NO2 and SO2, for different study areas. The trends are, for the most part, associated with economic and/or technological changes in energy use, as well as regional regulatory policies. Over the eastern US, both NO2 and SO2 levels decreased dramatically from 2005 to 2015, by more than 40 and 80 %, respectively, as a result of both technological improvements and stricter regulations of emissions. OMI confirmed large reductions in SO2 over eastern Europe's largest coal-fired power plants after installation of flue gas desulfurization devices. The North China Plain has the world's most severe SO2 pollution, but a decreasing trend has been observed since 2011, with about a 50 % reduction in 2012-2015, due to an economic slowdown and government efforts to restrain emissions from the power and industrial sectors. In contrast, India's SO2 and NO2 levels from coal power plants and smelters are growing at a fast pace, increasing by more than 100 and 50 %, respectively, from 2005 to 2015. Several SO2 hot spots observed over the Persian Gulf are probably related to oil and gas operations and indicate a possible underestimation of emissions from these sources in bottom-up emission inventories. Overall, OMI observations have proved valuable in documenting rapid changes in air quality over different

  3. Aura OMI observations of regional SO2 and NO2 pollution changes from 2005 to 2015

    Science.gov (United States)

    Krotkov, Nickolay A.; McLinden, Chris A; Li, Can; Lamsal, Lok N.; Celarier, Edward A.; Marchenko, Sergey V.; Swartz, William H.; Bucsela, Eric J.; Joiner, Joanna; Duncan, Bryan N.; hide

    2016-01-01

    The Ozone Monitoring Instrument (OMI) onboard NASA's Aura satellite has been providing global observations of the ozone layer and key atmospheric pollutant gases, such as nitrogen dioxide (NO2/ and sulfur dioxide (SO2/, since October 2004. The data products from the same instrument provide consistent spatial and temporal coverage and permit the study of anthropogenic and natural emissions on local-to-global scales. In this paper, we examine changes in SO2 and NO2 over some of the world's most polluted industrialized regions during the first decade of OMI observations. In terms of regional pollution changes, we see both upward and downward trends, sometimes in opposite directions for NO2 and SO2, for different study areas. The trends are, for the most part, associated with economic and/or technological changes in energy use, as well as regional regulatory policies. Over the eastern US, both NO2 and SO2 levels decreased dramatically from 2005 to 2015, by more than 40 and 80 %, respectively, as a result of both technological improvements and stricter regulations of emissions. OMI confirmed large reductions in SO2 over eastern Europe's largest coal-fired power plants after installation of flue gas desulfurization devices. The North China Plain has the world's most severe SO2 pollution, but a decreasing trend has been observed since 2011, with about a 50% reduction in 2012- 2015, due to an economic slowdown and government efforts to restrain emissions from the power and industrial sectors. In contrast, India's SO2 and NO2 levels from coal power plants and smelters are growing at a fast pace, increasing by more than 100 and 50 %, respectively, from 2005 to 2015. Several SO2 hot spots observed over the Persian Gulf are probably related to oil and gas operations and indicate a possible underestimation of emissions from these sources in bottom-up emission inventories. Overall, OMI observations have proved valuable in documenting rapid changes in air quality over different

  4. Aura OMI observations of regional SO2 and NO2 pollution changes from 2005 to 2015

    Science.gov (United States)

    Krotkov, Nickolay A.; McLinden, Chris A; Li, Can; Lamsal, Lok N.; Celarier, Edward A.; Marchenko, Sergey V.; Swartz, William H.; Bucsela, Eric J.; Joiner, Joanna; Duncan, Bryan N.; Boersma, K. Folkert; Veefkind, J. Pepijn; Levelt, Pieternel F.; Fioletov, Vitali E.; Dickerson, Russell R.; He, Hao; Lu, Zifeng; Streets, David G.

    2016-01-01

    The Ozone Monitoring Instrument (OMI) onboard NASA's Aura satellite has been providing global observations of the ozone layer and key atmospheric pollutant gases, such as nitrogen dioxide (NO2/ and sulfur dioxide (SO2/, since October 2004. The data products from the same instrument provide consistent spatial and temporal coverage and permit the study of anthropogenic and natural emissions on local-to-global scales. In this paper, we examine changes in SO2 and NO2 over some of the world's most polluted industrialized regions during the first decade of OMI observations. In terms of regional pollution changes, we see both upward and downward trends, sometimes in opposite directions for NO2 and SO2, for different study areas. The trends are, for the most part, associated with economic and/or technological changes in energy use, as well as regional regulatory policies. Over the eastern US, both NO2 and SO2 levels decreased dramatically from 2005 to 2015, by more than 40 and 80 %, respectively, as a result of both technological improvements and stricter regulations of emissions. OMI confirmed large reductions in SO2 over eastern Europe's largest coal-fired power plants after installation of flue gas desulfurization devices. The North China Plain has the world's most severe SO2 pollution, but a decreasing trend has been observed since 2011, with about a 50% reduction in 2012- 2015, due to an economic slowdown and government efforts to restrain emissions from the power and industrial sectors. In contrast, India's SO2 and NO2 levels from coal power plants and smelters are growing at a fast pace, increasing by more than 100 and 50 %, respectively, from 2005 to 2015. Several SO2 hot spots observed over the Persian Gulf are probably related to oil and gas operations and indicate a possible underestimation of emissions from these sources in bottom-up emission inventories. Overall, OMI observations have proved valuable in documenting rapid changes in air quality over different

  5. Tropospheric vertical column densities of NO2 over managed dryland ecosystems (Xinjiang, China): MAX-DOAS measurements vs. 3-D dispersion model simulations based on laboratory-derived NO emission from soil samples

    Science.gov (United States)

    Mamtimin, B.; Behrendt, T.; Badawy, M. M.; Wagner, T.; Qi, Y.; Wu, Z.; Meixner, F. X.

    2015-01-01

    We report on MAX-DOAS observations of NO2 over an oasis-ecotone-desert ecosystem in NW China. There, local ambient NO2 concentrations originate from enhanced biogenic NO emission of intensively managed soils. Our target oasis "Milan" is located at the southern edge of the Taklimakan desert, very remote and well isolated from other potential anthropogenic and biogenic NOx sources. Four observation sites for MAX-DOAS measurements were selected, at the oasis centre, downwind and upwind of the oasis, and in the desert. Biogenic NO emissions in terms of (i) soil moisture and (ii) soil temperature of Milan oasis (iii) different land-cover type sub-units (cotton, Jujube trees, cotton/Jujube mixture, desert) were quantified by laboratory incubation of corresponding soil samples. Net potential NO fluxes were up-scaled to oasis scale by areal distribution and classification of land-cover types derived from satellite images using GIS techniques. A Lagrangian dispersion model (LASAT, Lagrangian Simulation of Aerosol Transport) was used to calculate the dispersion of soil emitted NO into the atmospheric boundary layer over Milan oasis. Three-dimensional (3-D) NO concentrations (30 m horizontal resolution) have been converted to 3-D NO2 concentrations, assuming photostationary state conditions. NO2 column densities were simulated by suitable vertical integration of modelled 3-D NO2 concentrations at those downwind and upwind locations, where the MAX-DOAS measurements were performed. Downwind-upwind differences (a direct measure of Milan oasis' contribution to the areal increase of ambient NO2 concentration) of measured and simulated slant (as well as vertical) NO2 column densities show excellent agreement. This agreement is considered as the first successful attempt to prove the validity of the chosen approach to up-scale laboratory-derived biogenic NO fluxes to ecosystem field conditions, i.e. from the spatial scale of a soil sample (cm2) to the size of an entire agricultural

  6. Tropospheric vertical column densities of NO2 over managed dryland ecosystems (Xinjiang, China): MAX-DOAS measurements vs. 3-D dispersion model simulations based on laboratory derived NO emission from soil samples

    Science.gov (United States)

    Mamtimin, B.; Behrendt, T.; Badawy, M. M.; Wagner, T.; Qi, Y.; Wu, Z.; Meixner, F. X.

    2014-07-01

    We report on MAX-DOAS observations of NO2 over an oasis-ecotone-desert ecosystem in NW-China. There, local ambient NO2 concentrations originate from enhanced biogenic NO emission of intensively managed soils. Our target oasis "Milan" is located at the southern edge of the Taklimakan desert, very remote and well isolated from other potential anthropogenic and biogenic NOx sources. Four observation sites for MAX-DOAS measurements were selected, at the oasis center, downwind and upwind of the oasis, and in the desert. Biogenic NO emissions in terms of (i) soil moisture and (ii) soil temperature of Milan oasis' (iii) different land-cover type sub-units (cotton, Jujube trees, cotton/Jujube mixture, desert) were quantified by laboratory incubation of corresponding soil samples. Net potential NO fluxes were up-scaled to oasis scale by areal distribution and classification of land-cover types derived from satellite images using GIS techniques. A Lagrangian dispersion model (LASAT, Lagrangian Simulation of Aerosol-Transport) was used to calculate the dispersion of soil emitted NO into the atmospheric boundary layer over Milan oasis. Three dimensional NO concentrations (30 m horizontal resolution) have been converted to 3-D NO2 concentrations, assuming photostationary state conditions. NO2 column densities were simulated by suitable vertical integration of modeled 3-D NO2 concentrations at those downwind and upwind locations, where the MAX-DOAS measurements were performed. Downwind-upwind differences (a direct measure of Milan oasis' contribution to the areal increase of ambient NO2 concentration) of measured and simulated slant (as well as vertical) NO2 column densities show excellent agreement. This agreement is considered as the first successful attempt to prove the validity of the chosen approach to up-scale laboratory derived biogenic NO fluxes to ecosystem field conditions, i.e. from the spatial scale of a soil sample (cm2) to the size of an entire agricultural

  7. Tropospheric vertical column densities of NO2 over managed dryland ecosystems (Xinjiang, China: MAX-DOAS measurements vs. 3-D dispersion model simulations based on laboratory derived NO emission from soil samples

    Directory of Open Access Journals (Sweden)

    B. Mamtimin

    2014-07-01

    Full Text Available We report on MAX-DOAS observations of NO2 over an oasis-ecotone-desert ecosystem in NW-China. There, local ambient NO2 concentrations originate from enhanced biogenic NO emission of intensively managed soils. Our target oasis "Milan" is located at the southern edge of the Taklimakan desert, very remote and well isolated from other potential anthropogenic and biogenic NOx sources. Four observation sites for MAX-DOAS measurements were selected, at the oasis center, downwind and upwind of the oasis, and in the desert. Biogenic NO emissions in terms of (i soil moisture and (ii soil temperature of Milan oasis' (iii different land-cover type sub-units (cotton, Jujube trees, cotton/Jujube mixture, desert were quantified by laboratory incubation of corresponding soil samples. Net potential NO fluxes were up-scaled to oasis scale by areal distribution and classification of land-cover types derived from satellite images using GIS techniques. A Lagrangian dispersion model (LASAT, Lagrangian Simulation of Aerosol-Transport was used to calculate the dispersion of soil emitted NO into the atmospheric boundary layer over Milan oasis. Three dimensional NO concentrations (30 m horizontal resolution have been converted to 3-D NO2 concentrations, assuming photostationary state conditions. NO2 column densities were simulated by suitable vertical integration of modeled 3-D NO2 concentrations at those downwind and upwind locations, where the MAX-DOAS measurements were performed. Downwind-upwind differences (a direct measure of Milan oasis' contribution to the areal increase of ambient NO2 concentration of measured and simulated slant (as well as vertical NO2 column densities show excellent agreement. This agreement is considered as the first successful attempt to prove the validity of the chosen approach to up-scale laboratory derived biogenic NO fluxes to ecosystem field conditions, i.e. from the spatial scale of a soil sample (cm2 to the size of an entire

  8. Tropospheric radiowave propagation beyond the horizon

    CERN Document Server

    Du Castel, François

    1966-01-01

    Tropospheric Radiowave Propagation Beyond the Horizon deals with developments concerning the tropospheric propagation of ultra-short radio waves beyond the horizon, with emphasis on the relationship between the theoretical and the experimental. Topics covered include the general conditions of propagation in the troposphere; general characteristics of propagation beyond the horizon; and attenuation in propagation. This volume is comprised of six chapters and begins with a brief historical look at the various stages that have brought the technique of transhorizon links to its state of developmen

  9. Interhemispheric differences of fMRI responses to visual stimuli in patients with side-fixed migraine aura

    DEFF Research Database (Denmark)

    Hougaard, Anders; Amin, Faisal Mohammad; Hoffmann, Michael B

    2014-01-01

    Migraine sufferers with aura often report photosensitivity and visual discomfort outside of attacks and many consider bright or flickering light an attack-precipitating factor. The nature of this visual hypersensitivity and its relation to the underlying pathophysiology of the migraine aura...... is unknown. Using fMRI measurements during visual stimulation we examined the visual cortical responsiveness of patients with migraine with aura. We applied a within-patient design by assessing functional interhemispheric differences in patients consistently experiencing visual aura in the same visual...... hemifield. We recruited 20 patients with frequent side-fixed visual aura attacks (≥90% of auras occurring in the same visual hemifield) and 20 age and sex matched healthy controls and compared the fMRI blood oxygenation level dependent (BOLD) responses to visual stimulation between symptomatic...

  10. Effects of tonabersat on migraine with aura: a randomised, double-blind, placebo-controlled crossover study

    DEFF Research Database (Denmark)

    Hauge, Anne Werner; Asghar, Mohammad Sohail; Schytz, Henrik W

    2009-01-01

    different between placebo and tonabersat groups (3.0 days in each group; p=0.09). Tonabersat was well tolerated but overall had more side-effects than placebo. INTERPRETATION: Tonabersat showed a preventive effect on attacks of migraine aura but no efficacy on non-aura attacks, in keeping with its known......BACKGROUND: Migraine with aura is thought likely to be caused by cortical spreading depression (CSD). Tonabersat inhibits CSD, and we therefore investigated whether tonabersat has a preventive effect in migraine with aura. METHODS: In this randomised, double-blind, placebo-controlled crossover...... inhibitory effect on CSD. The results support the theory that auras are caused by CSD and that this phenomenon is not involved in attacks without aura. FUNDING: Minster Pharmaceuticals; Lundbeck Foundation....

  11. Increased brainstem perfusion, but no blood-brain barrier disruption, during attacks of migraine with aura.

    Science.gov (United States)

    Hougaard, Anders; Amin, Faisal M; Christensen, Casper E; Younis, Samaira; Wolfram, Frauke; Cramer, Stig P; Larsson, Henrik B W; Ashina, Messoud

    2017-06-01

    See Moskowitz (doi:10.1093/brain/awx099) for a scientific commentary on this article.The migraine aura is characterized by transient focal cortical disturbances causing dramatic neurological symptoms that are usually followed by migraine headache. It is currently not understood how the aura symptoms are related to the headache phase of migraine. Animal studies suggest that cortical spreading depression, the likely mechanism of migraine aura, causes disruption of the blood-brain barrier and noxious stimulation of trigeminal afferents leading to activation of brainstem nuclei and triggering of migraine headache. We used the sensitive and validated technique of dynamic contrast-enhanced high-field magnetic resonance imaging to simultaneously investigate blood-brain barrier permeability and tissue perfusion in the brainstem (at the level of the lower pons), visual cortex, and brain areas of the anterior, middle and posterior circulation during spontaneous attacks of migraine with aura. Patients reported to our institution to undergo magnetic resonance imaging during the headache phase after presenting with typical visual aura. Nineteen patients were scanned during attacks and on an attack-free day. The mean time from attack onset to scanning was 7.6 h. We found increased brainstem perfusion bilaterally during migraine with aura attacks. Perfusion also increased in the visual cortex and posterior white matter following migraine aura. We found no increase in blood-brain barrier permeability in any of the investigated regions. There was no correlation between blood-brain barrier permeability, brain perfusion, and time from symptom onset to examination or pain intensity. Our findings demonstrate hyperperfusion in brainstem during the headache phase of migraine with aura, while the blood-brain barrier remains intact during attacks of migraine with aura. These data thus contradict the preclinical hypothesis of cortical spreading depression-induced blood-brain barrier

  12. Temperamental characteristics in childhood migraine without aura: a multicenter study

    Directory of Open Access Journals (Sweden)

    Esposito M

    2013-08-01

    Full Text Available Maria Esposito,1 Rosa Marotta,2 Beatrice Gallai,3 Lucia Parisi,4 Giuseppina Patriciello,1 Serena Marianna Lavano,2 Giovanni Mazzotta,5 Michele Roccella,4 Marco Carotenuto11Center for Childhood Headache, Clinic of Child and Adolescent Neuropsychiatry, Department of Mental Health, Physical and Preventive Medicine, Second University of Naples, Naples, Italy; 2Department of Psychiatry, "Magna Graecia" University of Catanzaro, Catanzaro, Italy; 3Unit of Child and Adolescent Neuropsychiatry, University of Perugia, Perugia, Italy; 4Child Neuropsychiatry, Department of Psychology, University of Palermo, Palermo, Italy; 5Unit of Child and Adolescent Neuropsychiatry, AUSL Umbria 2, Terni, ItalyBackground: Children with migraine seem to be more anxious, sensitive, deliberate, cautious, fearful, vulnerable to frustration, tidy, and less physically enduring than comparisons. To the best our knowledge no studies about the temperamental and the characterial dimension aspects in childhood migraine was conducted. Therefore, the aim of the present study was to describe the temperamental and character aspects in a sample of children affected by migraine without aura (MoA and their relationship with clinical aspects of MoA such as frequency, duration, and severity of attacks.Materials and methods: In our study, 486 children affected by MoA (239 male, 247 female aged 7–12 years, (mean 10.04 ± 2.53 years and 518 typical developing children comparable for age (P = 0.227 and sex (P = 0.892 were enrolled to assess their temperamental characteristics. The mothers of all subjects filled out the Junior Temperament and Character Inventory: Parent Version.Results: Children affected by migraine show a higher prevalence of harm avoidance and persistence temperamental domains (P < 0.001 and significantly lower prevalence of the self-directedness character trait (P = 0.023 with respect to the comparisons, according to Cloninger's model. The Spearman rank correlation analysis

  13. Numerical study of the stopping of aura during migraine

    Directory of Open Access Journals (Sweden)

    Moussa A.

    2010-12-01

    Full Text Available This work is devoted to the study of migraine with aura in the human brain. Following [6], we class migraine as a propagation of a wave of depolarization through the cells. The mathematical model used, based on a reaction-diffusion equation, is briefly presented. The equation is considered in a duct containing a bend, in order to model one of the numerous circumvolutions of the brain. For a wide set of parameters, one can establish the existence of a critical radius below which the wave stops. The approximation scheme used for the simulations is first described and then a numerical study is realized, precising the dependence of the critical radius with respect to the different parameters of the model. Ce travail est consacré à l’étude de l’évolution d’une migraine avec aura dans le cerveau humain. Suivant [6], nous assimilons la migraine à une onde de dépolarisation attaquant les cellules du cerveau. Le modèle mathématique retenu, basé sur une équation de réaction-diffusion, est brièvement rappelé. Le domaine d’espace utilisé est constitué d’un conduit présentant un coude, afin de représenter l’une des nombreuses circonvolutions cérébrales. Pour une importante classe de paramètres, il est possible de mettre en évidence l’existence d’un rayon critique au delà duquel le front d’onde n’arrive pas à dépasser le coude. Après une description du schéma d’approximation utilisé, une étude numérique a été réalisée, visant à préciser la dépendance du rayon critique en fonction des différents paramètres du modèle.

  14. Regional Warming by Black Carbon and Tropospheric Ozone:A Review of Progresses and Research Challenges in China

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    Black carbon (BC) aerosol and tropospheric ozone (O3) are major air pollutants with short lifetimes of days to weeks in the atmosphere. These short-lived species have also made signifi cant contributions to global warming since the preindustrial times (IPCC, 2013). Reductions in short-lived BC and tropospheric O3 have been proposed as a complementary strategy to reductions in greenhouse gases. With the rapid economic development, concentrations of BC and tropospheric O3 are relatively high in China, and therefore quantifying their roles in regional climate change is especially important. This review summarizes the existing knowledge with regard to impacts of BC and tropospheric O3 on climate change in China and defi nes critical gaps needed to assess the climate benefi ts of emission control measures. Measured concentrations of BC and tropospheric O3, optical properties of BC, as well as the model estimates of radiative forcing by BC and tropospheric O3 are summarized. We also review regional and global modeling studies that have investigated climate change driven by BC and tropospheric O3 in China;predicted sign and magnitude of the responses in temperature and precipitation to BC/O3 forcing are presented. Based on the review of previous studies, research challenges pertaining to reductions in short-lived species to mitigate global warming are highlighted.

  15. Global tropospheric chemistry: A plan for action

    Science.gov (United States)

    1984-01-01

    Prompted by an increasing awareness of the influence of human activity on the chemistry of the global troposphere, a panel was formed to (1) assess the requirement for a global study of the chemistry of the troposphere; (2) develop a scientific strategy for a comprehensive plan taking into account the existing and projected programs of the government; (3) assess the requirements of a global study in terms of theoretical knowledge, numerical modeling, instrumentation, observing platforms, ground-level observational techniques, and other related needs; and (4) outline the appropriate sequence and coordination required to achieve the most effective utilization of available resources. Part 1 presents a coordinated national blueprint for scientific investigations of biogeochemical cycles in the global troposphere. part 2 presents much of the background information of the present knowledge and gaps in the understanding of tropospheric chemical cycles and processes from which the proposed program was developed.

  16. Performance Evaluation of Blind Tropospheric Delay correction ...

    African Journals Online (AJOL)

    Performance Evaluation of Blind Tropospheric Delay correction Models over Africa. ... consisting of surface meteorological models and global empirical models. ... GPT2w and UNB3M models with accurate International GNSS Service (IGS)- ...

  17. Evaluation of ACCMIP Outgoing Longwave Radiation from Tropospheric Ozone Using TES Satellite Observations.

    Science.gov (United States)

    Bowman, Kevin W.; Shindell, Drew Todd; Worden, H. M.; Lamarque, J. F.; Young, P. J.; Stevenson, D. S.; Qu, Z.; delaTorre, M.; Bergmann, D.; Cameron-Smith, P. J.; Collins, W. J.; Doherty, R.; Dalsoren, S. B.; Faluvegi, G.; Folberth, G.; Horowitz, L. W.; Josse, B. M.; Lee, Y. H.; MacKenzie, I. A.; Myhre, G.; Nagashima, T.; Naik, V.; Strode, S. A.; Kulawik, S. S..; Worden, J. R.

    2013-01-01

    We use simultaneous observations of tropospheric ozone and outgoing longwave radiation (OLR) sensitivity to tropospheric ozone from the Tropospheric Emission Spectrometer (TES) to evaluate model tropospheric ozone and its effect on OLR simulated by a suite of chemistry-climate models that participated in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP). The ensemble mean of ACCMIP models show a persistent but modest tropospheric ozone low bias (5-20 ppb) in the Southern Hemisphere (SH) and modest high bias (5-10 ppb) in the Northern Hemisphere (NH) relative to TES ozone for 2005-2010. These ozone biases have a significant impact on the OLR. Using TES instantaneous radiative kernels (IRK), we show that the ACCMIP ensemble mean tropospheric ozone low bias leads up to 120mW/ sq. m OLR high bias locally but zonally compensating errors reduce the global OLR high bias to 39+/- 41mW/ sq. m relative to TES data. We show that there is a correlation (Sq. R = 0.59) between the magnitude of the ACCMIP OLR bias and the deviation of the ACCMIP preindustrial to present day (1750-2010) ozone radiative forcing (RF) from the ensemble ozone RF mean. However, this correlation is driven primarily by models whose absolute OLR bias from tropospheric ozone exceeds 100mW/ sq. m. Removing these models leads to a mean ozone radiative forcing of 394+/- 42mW/ sq. m. The mean is about the same and the standard deviation is about 30% lower than an ensemble ozone RF of 384 +/- 60mW/ sq. m derived from 14 of the 16 ACCMIP models reported in a companion ACCMIP study. These results point towards a profitable direction of combining satellite observations and chemistry-climate model simulations to reduce uncertainty in ozone radiative forcing.

  18. Tropospheric column amount of ozone retrieved from SCIAMACHY limb-nadir-matching observations

    Directory of Open Access Journals (Sweden)

    F. Ebojie

    2013-08-01

    Full Text Available Tropospheric ozone, O3, has two sources: transport from the stratosphere and photochemical production in the troposphere. It plays important roles in atmospheric chemistry and climate change. In this manuscript we describe the retrieval of tropospheric O3 columns from limb-nadir matching (LNM observations of the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY instrument, which flies as part of the payload onboard the European Space Agency (ESA satellite Envisat. This retrieval technique is a residual approach that utilizes the subtraction of the stratospheric O3 columns, derived from the limb observations, from the total O3 columns, derived from the nadir observations. The technique requires accurate knowledge of the stratospheric O3 columns, the total O3 columns, tropopause height, and their associated errors. The stratospheric O3 columns were determined from the stratospheric O3 profile retrieved in the Hartley and Chappius bands, based on SCIAMACHY limb scattering measurements. The total O3 columns were also derived from SCIAMACHY measurements, in the nadir viewing mode using the Weighting Function Differential Optical Absorption Spectroscopy (WFDOAS technique in the Huggins band. Comparisons of the tropospheric O3 columns from SCIAMACHY and collocated measurements from ozonesondes, in both hemispheres between January 2003 and December 2011 show agreement to within 2–5 DU (1 DU = 2.69 × 1016 molecules cm−2. Comparison of tropospheric O3 from SCIAMACHY with the results from ozonesondes, the Tropospheric Emission Spectrometer (TES, and the LNM method combining Ozone Monitoring Instrument (OMI and Microwave Limb Sounder (MLS data (hereinafter referred to as OMI/MLS, have been investigated. We find that all four retrieved data sets show agreement within the error bars and exhibit strong seasonal variation, which differs in amplitude. The spatial distribution of tropospheric ozone observed shows pollution

  19. An intercomparison study of tropospheric NO2 columns retrieved from MAX-DOAS and simulated by regional air quality models

    Science.gov (United States)

    Blechschmidt, Anne-Marlene

    2016-04-01

    Tropospheric NO2 is hazardous to human health and can lead to tropospheric ozone formation, eutrophication of ecosystems and acid rain production. It is therefore very important to accurately observe and simulate tropospheric NO2 on a regional and global scale. In the present study, MAX-DOAS tropospheric NO2 column retrievals from three European measurement stations are applied for validation of a regional model ensemble. In general, there is a good agreement between simulated and retrieved NO2 column values for individual MAX-DOAS measurements, indicating that the model ensemble does well represent the emission and tropospheric chemistry of NOx. However, the model ensemble tends to overestimate low and underestimate high tropospheric NO2 column values, respectively. Pollution transport towards the stations is on average well represented by the models. However, large differences can be found for individual pollution plumes. Seasonal cycles are overestimated by the model ensemble, which could point to problems in simulating photochemistry. While weekly cycles are reproduced well by the models, model performance is rather poor for diurnal cycles. In particular, simulated morning rush hour peaks are not confirmed by MAX-DOAS retrievals, which may result from inappropriate hourly scaling of NOx emissions, possibly combined with errors in chemistry. Our results demonstrate that a large number of validation points are available from MAX-DOAS data, which should therefore be used more extensively in future regional air quality modelling studies.

  20. Radiative effects of tropospheric ionisation

    Directory of Open Access Journals (Sweden)

    K. L. Aplin

    2003-06-01

    Full Text Available Despite the increasing evidence that cosmic ray variations may influence clouds and climate, there has been little discussion of the direct radiative effects of atmospheric ionisation. Laboratory experiments show that hydrated molecular cluster-ions, formed in the atmosphere by cosmic rays, absorb in the infra-red continuum at wavelengths of 9–12 μm. The tropospheric magnitude of this effect is estimated: transmittance anomalies from clear sky ion concentrations peak at ~2% at 10 km in the mid-latitudes. A simple isothermal clear sky atmospheric model suggests the integrated effect of the absorption is ~2 Wm−2. The effect appears detectable in existing surface data sets; surface micrometeorological data shows a significant anticorrelation between downwelling infra-red radiation and atmospheric cosmic ray ionisation. This is consistent with the infra-red attenuation observed in laboratory studies of cluster-ion absorption. If atmospheric ionisation from cosmic rays has universally direct radiative effects, then reinterpretation of satellite cloud data may be necessary.

  1. Tapio Aura - tsemenditehas tuleb järgmisele põlvkonnale üle anda natuke paremas seisus / Tapio Aura ; interv. Toomas Kään

    Index Scriptorium Estoniae

    Aura, Tapio

    2005-01-01

    AS Kunda Nordic Tsement juhatuse esimees on kümne Eestis elatud ja töötatud aastaga ära õppinud eesti keele ning teinud tehasest tugeva, jätkusuutliku ja konkurentsivõimelise ettevõtte. Lisa: Eino Tapio Aura. Kommenteerib maxit Estonia AS tegevdirektor Viktor Valkiainen

  2. Tapio Aura - tsemenditehas tuleb järgmisele põlvkonnale üle anda natuke paremas seisus / Tapio Aura ; interv. Toomas Kään

    Index Scriptorium Estoniae

    Aura, Tapio

    2005-01-01

    AS Kunda Nordic Tsement juhatuse esimees on kümne Eestis elatud ja töötatud aastaga ära õppinud eesti keele ning teinud tehasest tugeva, jätkusuutliku ja konkurentsivõimelise ettevõtte. Lisa: Eino Tapio Aura. Kommenteerib maxit Estonia AS tegevdirektor Viktor Valkiainen

  3. No abnormalities of intrinsic brain connectivity in the interictal phase of migraine with aura.

    Science.gov (United States)

    Hougaard, A; Amin, F M; Magon, S; Sprenger, T; Rostrup, E; Ashina, M

    2015-04-01

    Functional neuroimaging studies have shown hyperresponsiveness of cortical areas to visual stimuli in migraine patients with aura outside of attacks. This may be a key feature in the initiation of aura episodes and possibly also migraine headache attacks. It is unknown if cortical dysfunction is present at rest, i.e. in the absence of any external stimuli. Functional magnetic resonance imaging is a powerful technique for evaluating resting state functional connectivity, i.e. coherence of brain activity across cerebral areas. The objective of this study was to investigate resting-state functional brain connectivity in migraineurs with aura outside of attacks using functional magnetic resonance imaging. Forty patients suffering from migraine with visual aura and 40 individually age and gender matched healthy controls with no history or family history of migraine were investigated. Following advanced denoising, the data were analyzed both in a hypothesis-driven fashion, testing for abnormalities involving 27 different brain areas of potential relevance to migraine with aura including the cortical visual areas, the amygdala and peri-aqueductal grey matter, and in a data-driven exploratory fashion (dual regression) in order to reveal any possible between-group differences of resting state networks. Age, gender, attack frequency and disease duration were included as nuisance variables. No differences of functional connectivity were found between patients and controls. The previously reported increased cortical hyperresponsivity in the interictal phase of migraine with aura is unlikely to be caused by abnormalities of intrinsic brain connectivity. The interictal migraine aura brain may be abnormally functioning only during exposure to external stimuli. © 2015 EAN.

  4. Increased intrinsic brain connectivity between pons and somatosensory cortex during attacks of migraine with aura.

    Science.gov (United States)

    Hougaard, Anders; Amin, Faisal Mohammad; Larsson, Henrik B W; Rostrup, Egill; Ashina, Messoud

    2017-02-27

    The neurological disturbances of migraine aura are caused by transient cortical dysfunction due to waves of spreading depolarization that disrupt neuronal signaling. The effects of these cortical events on intrinsic brain connectivity during attacks of migraine aura have not previously been investigated. Studies of spontaneous migraine attacks are notoriously challenging due to their unpredictable nature and patient discomfort. We investigated 16 migraine patients with visual aura during attacks and in the attack-free state using resting state fMRI. We applied a hypothesis-driven seed-based approach focusing on cortical visual areas and areas involved in migraine pain, and a data-driven independent component analysis approach to detect changes in intrinsic brain signaling during attacks. In addition, we performed the analyses after mirroring the MRI data according to the side of perceived aura symptoms. We found a marked increase in connectivity during attacks between the left pons and the left primary somatosensory cortex including the head and face somatotopic areas (peak voxel: P = 0.0096, (x, y, z) = (-54, -32, 32), corresponding well with the majority of patients reporting right-sided pain. For aura-side normalized data, we found increased connectivity during attacks between visual area V5 and the lower middle frontal gyrus in the symptomatic hemisphere (peak voxel: P = 0.0194, (x, y, z) = (40, 40, 12). The present study provides evidence of altered intrinsic brain connectivity during attacks of migraine with aura, which may reflect consequences of cortical spreading depression, suggesting a link between aura and headache mechanisms. Hum Brain Mapp, 2017. © 2017 Wiley Periodicals, Inc.

  5. A large impact of tropical biomass burning on CO and CO2 in the upper troposphere

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A large interannual variation of biomass burning emissions from Southeast Asia is associated with the ENSO events. During 1997/98 and 1994 El Nino years, uncontrolled wildfires of tropical rainforests and peat lands in Indonesia were enlarged due to a long drought. Enhanced CO injection into the upper troposphere from the intense Indonesian fires was clearly observed in the 8-year measurements from a regular flask sampling over the western Pacific using a JAL airliner between Australia and Japan. This airliner observation also revealed that upper tropospheric CO2 cycle largely changed during the 1997 El Nino year due partly to the biomass burning emissions. Widespread pollution from the biomass burnings in Southeast Asia was simulated using a CO tracer driven by a 3D global chemical transport model. This simulation indicates that tropical deep convections connected to rapid advection by the subtropical jet play a significant role in dispersing biomass-burning emissions from Southeast Asia on a global scale.

  6. Migraine with aura, bipolar depression, ACM aneurysm. A case report.

    Science.gov (United States)

    de Filippis, Sergio; Salvatori, Emiliano; Bozzao, Alessandro; Fantozzi, Luigi Maria; Martelletti, Paolo

    2005-04-01

    B.D. is a 48-year-old professional woman. She has been suffering for migraine since she was 28, but she did not have serious problems until last year, when headache episodes became more frequent and it was necessary an admission to emergency room. At the beginning, the events were about 6 per month, lasting from 2 to 4 days, beating and of high intensity together with nausea, vomit, photo and phonophobia and visual area. Looking at the anamnesis, we report a psychiatric treatment since about ten years, because of type II bipolar disorder. In spite of the psychopharmacological treatment, as the patient came in our Regional Headache Center, she talked about 7 events with aura (scintillating scotomas, emianopsia) per month, lasting 2-4 days with photo and phonophobia, nausea, crying crisis, anxiety. Although the neurological examination was normal, the sudden aggravation of pain symptomatology and the unresposiveness to usual painkillers, suggested a cerebral CT and CT-angiography. CT and CT-angiography discovered the presence of an aneurysm of the right middle cerebral artery (MCA) of 4 mm diameter, with parietal irregularities. The patient was operated to reduce the hemorrhagic risk, with a positive result. One year after the operation, the patient reports a decrease of headache events with a frequency of 2 per month, lasting only a few hours, which she can now solve with COXIB.

  7. Somatosensory and pharyngolaryngeal auras in temporal lobe epilepsy surgeries.

    Science.gov (United States)

    Weil, Alexander G; Surbeck, Werner; Rahme, Ralph; Bouthillier, Alain; Harroud, Adil; Nguyen, Dang Khoa

    2013-01-01

    Purpose. Somatosensory (SSA) and pharyngolaryngeal auras (PLA) may suggest an extratemporal onset (e.g., insula, second somatosensory area). We sought to determine the prognostic significance of SSA and PLA in temporal lobe epilepsy (TLE) patients undergoing epilepsy surgery. Methods. Retrospective review of all patients operated for refractory TLE at our institution between January 1980 and July 2007 comparing outcome between patients with SSA/PLA to those without. Results. 158 patients underwent surgery for pharmacoresistant TLE in our institution. Eleven (7%) experienced SSA/PLA as part of their seizures. All but one had lesional (including hippocampal atrophy/sclerosis) TLE. Compared to patients without SSA or PLA, these patients were older (P = 0.049), had a higher prevalence of early ictal motor symptoms (P = 0.022) and prior CNS infection (P = 0.022), and were less likely to have a localizing SPECT study (P = 0.025). A favorable outcome was achieved in 81.8% of patients with SSA and/or PLA and 90.4% of those without SSA or PLA (P > 0.05). Conclusion. Most patients with pharmacoresistant lesional TLE appear to have a favorable outcome following temporal lobectomy, even in the presence of SSA and PLA.

  8. Características clínicas da enxaqueca sem aura Clinical characteristics of migraine without aura

    Directory of Open Access Journals (Sweden)

    LUIZ PAULO DE QUEIROZ

    1998-03-01

    Full Text Available Um estudo aprofundado das características clínicas da enxaqueca sem aura (ESA revela alguns dados interessantes. Um questionário foi respondido por 200 pacientes que preenchiam os critérios da Sociedade Internacional de Cefaléia para ESA. O pico do início da enxaqueca foi entre 10 e 19 anos de idade. A cefaléia era restrita a um lado em 19%. Era exclusivamente bilateral em 9%. A maioria (86,2% dos pacientes que descreveram cefaléias em um único local localizou-a na área fronto-temporal. Cervicalgia estava associada aos ataques de enxaqueca em 70,5% e dor facial em 73,5%. O caráter latejante foi notado por 81%. Todos os pacientes descreveram a cefaléia como moderada a severa. Somente 55% disseram que a dor era agravada por atividades físicas rotineiras. Náusea ocorreu em 91%, foto e fonofobia em 77% e vômitos em 50%. Este olhar detalhado na ESA demonstra a grande complexidade dos seus sintomas.A detailed study of the clinical characteristics of migraine without aura (MOA reveals some interesting data. A questionnaire was returned by 200 patients who met the International Headache Society criteria for MOA. The peak of onset of migraine was between 10 and 19 years of age. The headache was side-locked in 19%. It was exclusively bilateral in 9%. The majority (86.2% of the patients who described headaches in only one site located them in the fronto-temporal area. Neck pain was associated with migraine attacks in 70.5% and face pain in 73.5%. A pounding quality was noted by 81%. Every patient described the headache as moderate to severe. Only 55% stated that it was aggravated by routine physical activity. Nausea occurred in 91%, photo and phonophobia in 77%, and vomiting in 50%. This close look at MOA uncovers a great complexity of symptoms.

  9. Understanding the Laminar Distribution of Tropospheric Ozone from Ground-Based, Airborne, Spaceborne, and Modeling Perspectives

    Science.gov (United States)

    Newchurch, Mike; Johnson, Matthew S.; Huang, Guanyu; Kuang, Shi; Wang, Lihua; Chance, Kelly; Liu, Xiong

    2016-01-01

    Laminar ozone structure is a ubiquitous feature of tropospheric-ozone distributions resulting from dynamic and chemical atmospheric processes. Understanding the characteristics of these ozone laminae and the mechanisms responsible for producing them is important to outline the transport pathways of trace gases and to quantify the impact of different sources on tropospheric background ozone. In this study, we present a new method to detect ozone laminae to understand their climatological characteristics of occurrence frequency in terms of thickness and altitude. We employ both ground-based and airborne ozone lidar measurements and other synergistic observations and modeling to investigate the sources and mechanisms such as biomass burning transport, stratospheric intrusion, lightning-generated NOx, and nocturnal low-level jets that are responsible for depleted or enhanced tropospheric ozone layers. Spaceborne (e.g., OMI (Ozone Monitoring Instrument), TROPOMI (Tropospheric Monitoring Instrument), TEMPO (Tropospheric Emissions: Monitoring of Pollution)) measurements of these laminae will observe greater horizontal extent and lower vertical resolution than balloon-borne or lidar measurements will quantify. Using integrated ground-based, airborne, and spaceborne observations in a modeling framework affords insight into how to gain knowledge of both the vertical and horizontal evolution of these ubiquitous ozone laminae.

  10. Global O3-CO correlations in a chemistry and transport model during July-August: evaluation with TES satellite observations and sensitivity to input meteorological data and emissions

    Science.gov (United States)

    Choi, Hyun-Deok; Liu, Hongyu; Crawford, James H.; Considine, David B.; Allen, Dale J.; Duncan, Bryan N.; Horowitz, Larry W.; Rodriguez, Jose M.; Strahan, Susan E.; Zhang, Lin; Liu, Xiong; Damon, Megan R.; Steenrod, Stephen D.

    2017-07-01

    We examine the capability of the Global Modeling Initiative (GMI) chemistry and transport model to reproduce global mid-tropospheric (618 hPa) ozone-carbon monoxide (O3-CO) correlations determined by the measurements from the Tropospheric Emission Spectrometer (TES) aboard NASA's Aura satellite during boreal summer (July-August). The model is driven by three meteorological data sets (finite-volume General Circulation Model (fvGCM) with sea surface temperature for 1995, Goddard Earth Observing System Data Assimilation System Version 4 (GEOS-4 DAS) for 2005, and Modern-Era Retrospective Analysis for Research and Applications (MERRA) for 2005), allowing us to examine the sensitivity of model O3-CO correlations to input meteorological data. Model simulations of radionuclide tracers (222Rn, 210Pb, and 7Be) are used to illustrate the differences in transport-related processes among the meteorological data sets. Simulated O3 values are evaluated with climatological profiles from ozonesonde measurements and satellite tropospheric O3 columns. Despite the fact that the three simulations show significantly different global and regional distributions of O3 and CO concentrations, they show similar patterns of O3-CO correlations on a global scale. All model simulations sampled along the TES orbit track capture the observed positive O3-CO correlations in the Northern Hemisphere midlatitude continental outflow and the Southern Hemisphere subtropics. While all simulations show strong negative correlations over the Tibetan Plateau, northern Africa, the subtropical eastern North Pacific, and the Caribbean, TES O3 and CO concentrations at 618 hPa only show weak negative correlations over much narrower areas (i.e., the Tibetan Plateau and northern Africa). Discrepancies in regional O3-CO correlation patterns in the three simulations may be attributed to differences in convective transport, stratospheric influence, and subsidence, among other processes. To understand how various

  11. Evaluation of Empirical Tropospheric Models Using Satellite-Tracking Tropospheric Wet Delays with Water Vapor Radiometer at Tongji, China

    OpenAIRE

    Miaomiao Wang; Bofeng Li

    2016-01-01

    An empirical tropospheric delay model, together with a mapping function, is commonly used to correct the tropospheric errors in global navigation satellite system (GNSS) processing. As is well-known, the accuracy of tropospheric delay models relies mainly on the correction efficiency for tropospheric wet delays. In this paper, we evaluate the accuracy of three tropospheric delay models, together with five mapping functions in wet delays calculation. The evaluations are conducted by comparing ...

  12. The Global Structure of UTLS Ozone in GEOS-5: A Multi-Year Assimilation of EOS Aura Data

    Science.gov (United States)

    Wargan, Krzysztof; Pawson, Steven; Olsen, Mark A.; Witte, Jacquelyn C.; Douglass, Anne R.; Ziemke, Jerald R.; Strahan, Susan E.; Nielsen, J. Eric

    2015-01-01

    Eight years of ozone measurements retrieved from the Ozone Monitoring Instrument (OMI) and the Microwave Limb Sounder, both on the EOS Aura satellite, have been assimilated into the Goddard Earth Observing System version 5 (GEOS-5) data assimilation system. This study thoroughly evaluates this assimilated product, highlighting its potential for science. The impact of observations on the GEOS-5 system is explored by examining the spatial distribution of the observation-minus-forecast statistics. Independent data are used for product validation. The correlation coefficient of the lower-stratospheric ozone column with ozonesondes is 0.99 and the bias is 0.5%, indicating the success of the assimilation in reproducing the ozone variability in that layer. The upper-tropospheric assimilated ozone column is about 10% lower than the ozonesonde column but the correlation is still high (0.87). The assimilation is shown to realistically capture the sharp cross-tropopause gradient in ozone mixing ratio. Occurrence of transport-driven low ozone laminae in the assimilation system is similar to that obtained from the High Resolution Dynamics Limb Sounder (HIRDLS) above the 400 K potential temperature surface but the assimilation produces fewer laminae than seen by HIRDLS below that surface. Although the assimilation produces 5 - 8 fewer occurrences per day (up to approximately 20%) during the three years of HIRDLS data, the interannual variability is captured correctly. This data-driven assimilated product is complementary to ozone fields generated from chemistry and transport models. Applications include study of the radiative forcing by ozone and tracer transport near the tropopause.

  13. Recent divergences in stratospheric water vapor measurements by frost point hygrometers and the Aura Microwave Limb Sounder

    Science.gov (United States)

    Hurst, Dale F.; Read, William G.; Vömel, Holger; Selkirk, Henry B.; Rosenlof, Karen H.; Davis, Sean M.; Hall, Emrys G.; Jordan, Allen F.; Oltmans, Samuel J.

    2016-09-01

    Balloon-borne frost point hygrometers (FPs) and the Aura Microwave Limb Sounder (MLS) provide high-quality vertical profile measurements of water vapor in the upper troposphere and lower stratosphere (UTLS). A previous comparison of stratospheric water vapor measurements by FPs and MLS over three sites - Boulder, Colorado (40.0° N); Hilo, Hawaii (19.7° N); and Lauder, New Zealand (45.0° S) - from August 2004 through December 2012 not only demonstrated agreement better than 1 % between 68 and 26 hPa but also exposed statistically significant biases of 2 to 10 % at 83 and 100 hPa (Hurst et al., 2014). A simple linear regression analysis of the FP-MLS differences revealed no significant long-term drifts between the two instruments. Here we extend the drift comparison to mid-2015 and add two FP sites - Lindenberg, Germany (52.2° N), and San José, Costa Rica (10.0° N) - that employ FPs of different manufacture and calibration for their water vapor soundings. The extended comparison period reveals that stratospheric FP and MLS measurements over four of the five sites have diverged at rates of 0.03 to 0.07 ppmv year-1 (0.6 to 1.5 % year-1) from ˜ 2010 to mid-2015. These rates are similar in magnitude to the 30-year (1980-2010) average growth rate of stratospheric water vapor ( ˜ 1 % year-1) measured by FPs over Boulder (Hurst et al., 2011). By mid-2015, the FP-MLS differences at some sites were large enough to exceed the combined accuracy estimates of the FP and MLS measurements.

  14. Evaluation of tropospheric ozone columns derived from assimilated GOME ozone profile observations

    Directory of Open Access Journals (Sweden)

    A. T. J. de Laat

    2009-05-01

    Full Text Available Tropospheric O3 column estimates are produced and evaluated from spaceborne O3 observations by the subtraction of assimilated O3 profile observations from total column observations, the so-called Tropospheric O3 ReAnalysis or TORA method. Here we apply the TORA method to six years (1996–2001 of ERS-2 GOME/TOMS total O3 and ERS-2 GOME O3 profile observations using the TM5 global chemistry-transport model with a linearized O3 photochemistry parameterization scheme.

    Free running TM5 simulations show good agreement with O3 sonde observations in the upper-tropospheric and lower stratospheric (UTLS. Assimilation of GOME O3 profile observations improves the comparisons in the tropical UTLS region but slightly degrades the model-to-sonde comparisons in the extra-tropical UTLS for both short day-do-day variability as well as for monthly means. We suggest that this degradation is related to the large ground pixel size of the GOME O3 measurements (960×100 km in combination with retrieval and calibration errors. The assimilation of GOME O3 profile observations does counter the gradual multiyear mid-latitude stratospheric O3 accumulation caused by the overstrong stratospheric meridional circulation in TM5.

    The evaluation of daily and monthly tropospheric O3 columns obtained from total column observations and using the TORA methodology shows realistic residuals within the tropics but unrealistically large deviations outside of the tropics, although average biases remain small for the monthly means. The findings of this paper suggest that improvements can be expected by using O3 observations from present-day instruments like MetOp/GOME-2 and EOS-AURA/OMI.

  15. Microemboli may link spreading depression, migraine aura, and patent foramen ovale.

    Science.gov (United States)

    Nozari, Ala; Dilekoz, Ergin; Sukhotinsky, Inna; Stein, Thor; Eikermann-Haerter, Katharina; Liu, Christina; Wang, Yumei; Frosch, Matthew P; Waeber, Christian; Ayata, Cenk; Moskowitz, Michael A

    2010-02-01

    Patent foramen ovale and pulmonary arteriovenous shunts are associated with serious complications such as cerebral emboli, stroke, and migraine with aura. The pathophysiological mechanisms that link these conditions are unknown. We aimed to establish a mechanism linking microembolization to migraine aura in an experimental animal model. We introduced particulate or air microemboli into the carotid circulation in mice to determine whether transient microvascular occlusion, insufficient to cause infarcts, triggered cortical spreading depression (CSD), a propagating slow depolarization that underlies migraine aura. Air microemboli reliably triggered CSD without causing infarction. Polystyrene microspheres (10 microm) or cholesterol crystals (<70 microm) triggered CSD in 16 of 28 mice, with 60% of the mice (40% of those with CSD) showing no infarcts or inflammation on detailed histological analysis of serial brain sections. No evidence of injury was detected on magnetic resonance imaging examination (9.4T; T2 weighted) in 14 of 15 selected animals. The occurrence of CSD appeared to be related to the magnitude and duration of flow reduction, with a triggering mechanism that depended on decreased brain perfusion but not sustained tissue damage. In a mouse model, microemboli triggered CSD, often without causing microinfarction. Paradoxical embolization then may link cardiac and extracardiac right-to-left shunts to migraine aura. If translatable to humans, a subset of migraine auras may belong to a spectrum of hypoperfusion disorders along with transient ischemic attacks and silent infarcts.

  16. Typical aura without headache: a case report and review of the literature.

    Science.gov (United States)

    He, Yusheng; Li, Yancheng; Nie, Zhiyu

    2015-02-24

    Typical aura without headache (TAWH), which has been rarely reported both at home and abroad, is a rare type of migraine with aura. This is a report on a 64-year-old Chinese migraineur who has had recurrent typical visual aura without headache attacks for more than 30 years, and has been misdiagnosed as having had transient ischemic attacks (TIA) many times. He mainly experienced episodes of 'homonymous blurred vision' or photopsia, which presented as different shapes located at the side or above his visual field, for example, patchy, cord-like, zigzag, curtain-like or irregular shapes. The shape was inconsistent during each attack, however, the color was mainly gray or light blue. The visual symptoms gradually disappeared in about 30 minutes. Our patient has never suffered a headache attack during or after the visual aura. Normal results were observed in his neurological and eye examinations, complete blood test, electroencephalogram and neuroimaging examination. TAWH is an uncommon phenomenon of migraine. Migraine with visual aura mainly presents positive and dynamic symptoms. It has a benign course and can be diagnosed after exclusion of other organic diseases such as TIA and epilepsy.

  17. Global distribution and trends of tropospheric ozone: An observation-based review

    Directory of Open Access Journals (Sweden)

    O. R. Cooper

    2014-07-01

    Full Text Available Abstract Tropospheric ozone plays a major role in Earth’s atmospheric chemistry processes and also acts as an air pollutant and greenhouse gas. Due to its short lifetime, and dependence on sunlight and precursor emissions from natural and anthropogenic sources, tropospheric ozone’s abundance is highly variable in space and time on seasonal, interannual and decadal time-scales. Recent, and sometimes rapid, changes in observed ozone mixing ratios and ozone precursor emissions inspired us to produce this up-to-date overview of tropospheric ozone’s global distribution and trends. Much of the text is a synthesis of in situ and remotely sensed ozone observations reported in the peer-reviewed literature, but we also include some new and extended analyses using well-known and referenced datasets to draw connections between ozone trends and distributions in different regions of the world. In addition, we provide a brief evaluation of the accuracy of rural or remote surface ozone trends calculated by three state-of-the-science chemistry-climate models, the tools used by scientists to fill the gaps in our knowledge of global tropospheric ozone distribution and trends.

  18. Global Distribution and Trends of Tropospheric Ozone: An Observation-Based Review

    Science.gov (United States)

    Cooper, O. R.; Parrish, D. D.; Ziemke, J.; Cupeiro, M.; Galbally, I. E.; Gilge, S.; Horowitz, L.; Jensen, N. R.; Lamarque, J.-F.; Naik, V.; hide

    2014-01-01

    Tropospheric ozone plays a major role in Earth's atmospheric chemistry processes and also acts as an air pollutant and greenhouse gas. Due to its short lifetime, and dependence on sunlight and precursor emissions from natural and anthropogenic sources, tropospheric ozone's abundance is highly variable in space and time on seasonal, interannual and decadal time-scales. Recent, and sometimes rapid, changes in observed ozone mixing ratios and ozone precursor emissions inspired us to produce this up-to-date overview of tropospheric ozone's global distribution and trends. Much of the text is a synthesis of in situ and remotely sensed ozone observations reported in the peer-reviewed literature, but we also include some new and extended analyses using well-known and referenced datasets to draw connections between ozone trends and distributions in different regions of the world. In addition, we provide a brief evaluation of the accuracy of rural or remote surface ozone trends calculated by three state-of-the-science chemistry-climate models, the tools used by scientists to fill the gaps in our knowledge of global tropospheric ozone distribution and trends.

  19. Attachment styles in children affected by migraine without aura

    Directory of Open Access Journals (Sweden)

    Esposito M

    2013-10-01

    Full Text Available Maria Esposito,1 Lucia Parisi,2 Beatrice Gallai,3 Rosa Marotta,4 Anna Di Dona,1 Serena Marianna Lavano,2 Michele Roccella,4 Marco Carotenuto11Center for Childhood Headache, Clinic of Child and Adolescent Neuropsychiatry, Department of Mental Health, Physical and Preventive Medicine, Second University of Naples, Naples, Italy; 2Child Neuropsychiatry, Department of Psychology, University of Palermo, Palermo, Italy; 3Unit of Child and Adolescent Neuropsychiatry, University of Perugia, Perugia, Italy; 4Department of Psychiatry, The Magna Graecia University of Catanzaro, Catanzaro, ItalyBackground: In recent years, great attention has been given to the presence of psychological problems and psychiatric comorbidity that are also present in children affected by primary headaches. The relationship between pain and attachment has been identified, and it may be that pain perception may change in relation with specific attachment styles. The aim of the present study was to assess the prevalent attachment style and verify its putative relationship and correlation with the main characteristics of migraine attacks, in school-aged children affected by migraine without aura (MoA.Materials and methods: The study population consisted of 219 children (103 males, 116 females aged between 6 and 11 years (mean 8.96 ± 2.14 years, consecutively referred for MoA compared with 381 healthy controls (174 males, 207 females; mean age 9.01 ± 1.75 years randomly selected from schools. All the children were classified according to the attachment typologies of the Italian modified version of the Separation Anxiety Test; monthly headache frequency and mean headache duration were assessed from daily headache diaries kept by all the children. Headache intensity was assessed on a visual analogue scale. The chi-square test and t-test, where appropriate, were applied, and the Spearman rank correlation test was applied to explore the relationship between the types of attachment

  20. Distribution of tropical tropospheric water vapor

    Science.gov (United States)

    Sun, De-Zheng; Lindzen, Richard S.

    1993-01-01

    Utilizing a conceptual model for tropical convection and observational data for water vapor, the maintenance of the vertical distribution of the tropical tropospheric water vapor is discussed. While deep convection induces large-scale subsidence that constrains the turbulent downgradient mixing to within the convective boundary layer and effectively dries the troposphere through downward advection, it also pumps hydrometeors into the upper troposphere, whose subsequent evaporation appears to be the major source of moisture for the large-scale subsiding motion. The development of upper-level clouds and precipitation from these clouds may also act to dry the outflow, thus explaining the low relative humidity near the tropopause. A one-dimensional model is developed to simulate the mean vertical structure of water vapor in the tropical troposphere. It is also shown that the horizontal variation of water vapor in the tropical troposphere above the trade-wind boundary layer can be explained by the variation of a moisture source that is proportional to the amount of upper-level clouds. Implications for the nature of water vapor feedback in global warming are discussed.

  1. Exploiting Aura OMI Level 2 Data with High Resolution Visualization

    Science.gov (United States)

    Wei, J. C.; Yang, W.; Johnson, J. E.; Zhao, P.; Gerasimov, I. V.; Pham, L.; Vicente, G. A.; Shen, S.

    2014-12-01

    Satellite data products are important for a wide variety of applications that can bring far-reaching benefits to the science community and the broader society. These benefits can best be achieved if the satellite data are well utilized and interpreted, such as model inputs from satellite, or extreme event (such as volcano eruption, dust storm, …etc) interpretation from satellite. Unfortunately, this is not always the case, despite the abundance and relative maturity of numerous satellite data products provided by NASA and other organizations. One way to help users better understand the satellite data is to provide data along with 'Images', including accurate pixel-level (Level 2) information, pixel coverage area delineation, and science team recommended quality screening for individual geophysical parameters. Goddard Earth Sciences Data and Information Services Center (GES DISC) always strives to best support (i.e., Software-as-a-service, SaaS) the user-community for NASA Earth Science Data. In this case, we will present a new visualization tool that helps users exploiting Aura Ozone Monitoring Instrument (OMI) Level 2 data. This new visualization service utilizes Open Geospatial Consortium (OGC) standard-compliant Web Mapping Service (WMS) and Web Coverage Service (WCS) calls in the backend infrastructure. The functionality of the service allows users to select data sources (e.g., multiple parameters under the same measurement, like NO2 and SO2 from OMI Level 2 or same parameter with different methods of aggregation, like NO2 in OMNO2G and OMNO2D products), defining area-of-interest and temporal extents, zooming, panning, overlaying, sliding, and data subsetting and reformatting. The interface will also be able to connect to other OGC WMS and WCS servers, which will greatly enhance its expandability to integrate additional outside data/map sources (such as Global Imagery Browse Services (GIBS)).

  2. Circulating endothelial microparticles in female migraineurs with aura.

    Science.gov (United States)

    Liman, Thomas G; Bachelier-Walenta, Katrin; Neeb, Lars; Rosinski, Jana; Reuter, Uwe; Böhm, Michael; Endres, Matthias

    2015-02-01

    Endothelial microparticles (EMPs) are vesicles that are released from activated endothelial cells and serve as a surrogate for endothelial dysfunction (ED). ED may be involved in migraine pathophysiology and contribute to the increased risk of ischemic stroke, particularly in female migraineurs with aura (MA). We sought to determine whether EMPs are elevated in women with MA. In this case-control study, EMPs were detected by analysing surface markers using fluorescence-activated cell sorting (FACS). Surface markers were measured covering the main cell lines relevant in cardiovascular disease like endothelial cells, platelets, monocytes and leucocytes. Microparticles (MPs) were identified in correlation to calibration by 1 -µm calibrator beads (Beckman Coulter). Arterial stiffness was assessed using fingertip tonometry and the heart rate-adjusted augmentation index (AI). We included 29 patients with MA and 29 matched controls. MA patients had significantly higher EMPs (CD62E(+)AnnexinV(+): 5142/µl vs 1535/µl; p < 0.001; CD144(+)AnnexinV(+): 6683/µl vs 3107/µl; p < 0.001), monocytic (CD14(+)AnnexinV(+) 6378 vs 3161; p < 0.001), and platelet MPs (CD62P(+)CD42b(+)AnnexinV(+) 5450 vs 3204; p < 0.001). Activated EMPs (CD62E(+)AnnexinV(+)) correlated with heart-rate adjusted AI (r = 0.46; p < 001). EMP levels are significantly elevated in women with MA and correlated with increased AI. Our findings suggest that endothelial activation is present in women with MA. This might contribute to higher stroke risk in MA. © International Headache Society 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  3. Air Quality Research and Applications Using AURA OMi Data

    Science.gov (United States)

    Bhartia, P.K.; Gleason, J.F.; Torres, O.; Levelt, P.; Liu, X.; Ziemke, J.; Chandra, S.; Krotkov, N.

    2007-01-01

    The Ozone Monitoring Instrument (OMI) on EOS Aura is a new generation of satellite remote sensing instrument designed to measure trace gas and aerosol absorption at the UV and blue wavelengths. These measurements are made globally at urban scale resolution with no inter-orbital gaps that make them potentially very useful for air quality research, such as the determination of the sources and processes that affect global and regional air quality, and to develop applications such as air quality forecast. However, the use of satellite data for such applications is not as straight forward as satellite data have been for stratospheric research. There is a need for close interaction between the satellite product developers, in-situ measurement programs, and the air quality research community to overcome some of the inherent difficulties in interpreting data from satellite-based remote sensing instruments. In this talk we will discuss the challenges and opportunities in using OMI products for air quality research and applications. A key conclusion of this work is that to realize the full potential of OMI measurements it will be necessary to combine OMI data with data from instruments such as MLS, MODIS, AIRS, and CALIPSO that are currently flying in the "A-train" satellite constellation. In addition similar data taken by satellites crossing the earth at different local times than the A-train (e.g., the recently MetOp satellite) would need to be processed in a consistent manner to study diurnal variability, and to capture the effects on air quality of rapidly changing events such as wild fires.

  4. Abnormal sensorimotor plasticity in migraine without aura patients.

    Science.gov (United States)

    Pierelli, Francesco; Iacovelli, Elisa; Bracaglia, Martina; Serrao, Mariano; Coppola, Gianluca

    2013-09-01

    The period between migraine attacks is characterized by paradoxical responses to repetitive sensory and transcranial magnetic stimulation (TMS). Abnormal long-term cortical functional plasticity may play a role and can be assessed experimentally by paired associative stimulation (PAS), in which somatosensory peripheral nerve stimuli are followed by TMS of the motor cortex. Changes in motor-evoked potential (MEP) amplitudes were recorded in 16 migraine without aura patients (MO) and 15 healthy volunteers (HV) before and after PAS, which consisted of 90 peripheral electrical right ulnar nerve stimulations and subsequent TMS pulses over the first dorsal interosseous (FDI) muscle activation site with a delay of 10 ms (excitability depressing) or 25 ms (excitability enhancing). As a control experiment of the 31 subjects studied, 8 (4 MO and 4 HV) also underwent PAS10 earlier, the recording of somatosensory high-frequency oscillations (HFOs) reflecting thalamocortical activation (early HFOs). Although PAS10 reduced MEP amplitudes in HV (-17.7%), it significantly increased amplitudes in MO (+35.9%). Although in HV MEP amplitudes were significantly potentiated (+55.1) after PAS25, only a slight, nonsignificant increase was observed in MO (+18.8%). In the control experiment, performed on 8 subjects pooled together, Pearson's correlation showed an inverse relationship between the percentage of MEP amplitude changes after PAS10 and early HFO amplitudes (r=-0.81; P=.01). Because we observed that the more deficient the long-term PAS-induced change, the more the thalamocortical activation decreased, we hypothesize that the abnormalities in long-term cortical plasticity observed in the interictal period between migraine episodes could be due to altered thalamic control.

  5. Tropospheric chemistry in the integrated forecasting system of ECMWF

    Directory of Open Access Journals (Sweden)

    J. Flemming

    2014-11-01

    Full Text Available A representation of atmospheric chemistry has been included in the Integrated Forecasting System (IFS of the European Centre for Medium-range Weather Forecasts (ECMWF. The new chemistry modules complement the aerosol modules of the IFS for atmospheric composition, which is named C-IFS. C-IFS for chemistry supersedes a coupled system, in which the Chemical Transport Model (CTM Model for OZone and Related chemical Tracers 3 was two-way coupled to the IFS (IFS-MOZART. This paper contains a description of the new on-line implementation, an evaluation with observations and a comparison of the performance of C-IFS with MOZART and with a re-analysis of atmospheric composition produced by IFS-MOZART within the Monitoring Atmospheric Composition and Climate (MACC project. The chemical mechanism of C-IFS is an extended version of the Carbon Bond 2005 (CB05 chemical mechanism as implemented in the CTM Transport Model 5 (TM5. CB05 describes tropospheric chemistry with 54 species and 126 reactions. Wet deposition and lightning nitrogen monoxide (NO emissions are modelled in C-IFS using the detailed input of the IFS physics package. A one-year simulation by C-IFS, MOZART and the MACC re-analysis is evaluated against ozonesondes, carbon monoxide (CO aircraft profiles, European surface observations of ozone (O3, CO, sulphur dioxide (SO2 and nitrogen dioxide (NO2 as well as satellite retrievals of CO, tropospheric NO2 and formaldehyde. Anthropogenic emissions from the MACC/CityZen (MACCity inventory and biomass burning emissions from the Global Fire Assimilation System (GFAS data set were used in the simulations by both C-IFS and MOZART. C-IFS (CB05 showed an improved performance with respect to MOZART for CO, upper tropospheric O3, winter time SO2 and was of a similar accuracy for other evaluated species. C-IFS (CB05 is about ten times more computationally efficient than IFS-MOZART.

  6. Familial hemiplegic migraine locus on 19p13 is involved in the common forms of migraine with and without aura

    NARCIS (Netherlands)

    A. May (Arne); R.A. Ophoff (Roel); G.M. Terwindt (Gisela); C. Urban; R. van Eijk (Ronald); J. Haan (Joost); H.C. Diener (Hans Christoph); D. Lindhout (Dick); R.R. Frants (Rune); L.A. Sandkuijl (Lodewijk); M.D. Ferrari (Michel)

    1995-01-01

    textabstractMigraine is a common neurological disease of two main types: migraine with aura and migraine without aura. Familial clustering suggests that genetic factors are involved in the etiology of migraine. Recently, a gene for familial hemiplegic migraine, a rare autosomal dominant subtype of m

  7. Abnormal brain processing of pain in migraine without aura: a high-density EEG brain mapping study

    DEFF Research Database (Denmark)

    Egsgaard, L L; Jensen, R; Buchgreitz, L

    2010-01-01

    In the present study we used high-density EEG brain mapping to investigate spatio-temporal aspects of brain activity in response to experimentally induced muscle pain in 17 patients with migraine without aura and 15 healthy controls. Painful electrical stimuli were applied to the trapezius muscle...... to the tonic muscle pain condition (z = 29 mm vs. z =¿-13 mm, P aura....

  8. Familial hemiplegic migraine locus on 19p13 is involved in the common forms of migraine with and without aura

    NARCIS (Netherlands)

    A. May (Arne); R.A. Ophoff (Roel); G.M. Terwindt (Gisela); C. Urban; R. van Eijk (Ronald); J. Haan (Joost); H.C. Diener (Hans Christoph); D. Lindhout (Dick); R.R. Frants (Rune); L.A. Sandkuijl (Lodewijk); M.D. Ferrari (Michel)

    1995-01-01

    textabstractMigraine is a common neurological disease of two main types: migraine with aura and migraine without aura. Familial clustering suggests that genetic factors are involved in the etiology of migraine. Recently, a gene for familial hemiplegic migraine, a rare autosomal dominant subtype of m

  9. Interhemispheric differences of fMRI responses to visual stimuli in patients with side-fixed migraine aura.

    Science.gov (United States)

    Hougaard, Anders; Amin, Faisal Mohammad; Hoffmann, Michael B; Rostrup, Egill; Larsson, Henrik B W; Asghar, Mohammad Sohail; Larsen, Vibeke Andrée; Olesen, Jes; Ashina, Messoud

    2014-06-01

    Migraine sufferers with aura often report photosensitivity and visual discomfort outside of attacks and many consider bright or flickering light an attack-precipitating factor. The nature of this visual hypersensitivity and its relation to the underlying pathophysiology of the migraine aura is unknown. Using fMRI measurements during visual stimulation we examined the visual cortical responsiveness of patients with migraine with aura. We applied a within-patient design by assessing functional interhemispheric differences in patients consistently experiencing visual aura in the same visual hemifield. We recruited 20 patients with frequent side-fixed visual aura attacks (≥90% of auras occurring in the same visual hemifield) and 20 age and sex matched healthy controls and compared the fMRI blood oxygenation level dependent (BOLD) responses to visual stimulation between symptomatic and asymptomatic hemispheres during the interictal phase and between migraine patients and controls. BOLD responses were selectively increased in the symptomatic hemispheres. This was found in the inferior parietal lobule (P = 0.002), the inferior frontal gyrus (P = 0.003), and the superior parietal lobule (P = 0.017). The affected cortical areas comprise a visually driven functional network involved in oculomotor control, guidance of movement, motion perception, visual attention, and visual spatial memory. The patients also had significantly increased response in the same cortical areas when compared to controls (P aura. These findings suggest a hyperexcitability of the visual system in the interictal phase of migraine with visual aura.

  10. Investigations of functional and structural changes in migraine with aura by magnetic resonance imaging

    DEFF Research Database (Denmark)

    Hougaard, Anders

    2015-01-01

    technology to study these features of migraine with aura (MA) is functional magnetic resonance imaging (fMRI), which has the potential not only to detect, but also to localize hypersensitive cortex. The main objective of this thesis was to investigate the cortical responsivity of patients with MA during...... visual stimulation using fMRI. To optimize sensitivity, we applied a within-patient design by assessing functional interhemispheric differences in patients consistently experiencing visual aura in the same visual hemifield. To validate our data analysis methods, we initially studied healthy volunteers.......e. ≥= 90% of auras occurring in the same visual hemifield (study II). To circumvent bias relating to differences between right and left hemispheres (e.g. caused by physiological left/right bias, asymmetry of the visual stimulation or magnetic field inhomogeneity of the scanner), we included an equal number...

  11. Structural gray matter abnormalities in migraine relate to headache lateralization, but not aura

    DEFF Research Database (Denmark)

    Hougaard, Anders; Amin, Faisal M; Hoffmann, Michael B

    2015-01-01

    BACKGROUND: The hallmark of migraine aura (MA) is transient cortical dysfunction but it is not known if MA is associated with structural cortical or subcortical changes. To determine the relation between MA and structural gray matter abnormalities, we studied a unique sample of 20 patients...... regions of interest. Within-subject comparisons were made with regard to aura symptoms (N = 20 vs 20) and with regard to headache (N = 13 vs 13). RESULTS: We found no differences in gray matter structure with regard to aura symptoms in MA patients. Comparing the typical migraine headache side...... of the patients to the contralateral side revealed a difference in cortical thickness in the inferior frontal gyrus (mean difference 0.12 mm, p = 0.036). CONCLUSION: MA per se is associated with abnormal function but not with lateralized abnormalities of gray matter structure. Alteration of the inferior frontal...

  12. Migraine with aura and risk of silent brain infarcts and white matter hyperintensities

    DEFF Research Database (Denmark)

    Gaist, David; Garde, Ellen; Blaabjerg, Morten

    2016-01-01

    A small number of population-based studies reported an association between migraine with aura and risk of silent brain infarcts and white matter hyperintensities in females. We investigated these relations in a population-based sample of female twins. We contacted female twins ages 30-60 years...... identified through the population-based Danish Twin Registry. Based on questionnaire responses, twins were invited to participate in a telephone-based interview conducted by physicians. Headache diagnoses were established according to the International Headache Society criteria. Cases with migraine with aura......% confidence interval): 0.17 (-0.08 to 0.41) cm(3)] and a similar difference was present in analyses restricted to twin pairs discordant for migraine with aura [adjusted mean difference 0.21 (-0.20 to 0.63)], but these differences did not reach statistical significance. We found no evidence of an association...

  13. Cerebral blood flow velocities are reduced during attacks of unilateral migraine without aura

    DEFF Research Database (Denmark)

    Thomsen, L L; Iversen, Helle Klingenberg; Olesen, J

    1995-01-01

    aura in 25 patients. Blood velocity in the middle cerebral artery was lower on the headache side (59 cm/s) than on the non-headache side (65 cm/s) during the migraine attack. No such difference was found outside of attack (65 cm/s both sides). The difference (headache side minus non-headache side......) was on average -6.1 cm/s during attack compared to -0.4 cm/s outside of attack (p = 0.01). Assuming that rCBF is unchanged during attacks of migraine without aura, our results suggest a 9% increase in middle cerebral artery lumen (cross-sectional area) on the affected side during unilateral attacks of migraine...... without aura. The findings, however, do not necessarily mean that arterial dilatation is the only or even the most significant cause of pain....

  14. Perfusion and pH MRI in familial hemiplegic migraine with prolonged aura.

    Science.gov (United States)

    Blicher, Jakob Udby; Tietze, Anna; Donahue, Manus J; Smith, Seth A; Østergaard, Leif

    2016-03-01

    To investigate tissue flow disturbance and hypoxia during migraine aura, we studied a case of familial hemiplegic migraine (FHM) using novel magnetic resonance imaging (MRI) techniques. A 44-year-old male was admitted with suspected stroke because of confusion and aphasia. Initial gadolinium-based perfusion MRI showed a decrease in cerebral blood flow and an increase in capillary flow disturbances within the left hemisphere. Later during the prolonged aura phase, chemical exchange saturation transfer MRI indicated a drop in pH in the affected area. The patient was diagnosed with an R908Q mutation in the ATP1A2 gene causing FHM type 2. During prolonged aura in FHM, MRI shows reduced CBF, capillary flow disturbances and a possible pH drop that could indicate tissue hypoxia. © International Headache Society 2015.

  15. Impact of geoengineered aerosols on the troposphere and stratosphere

    Energy Technology Data Exchange (ETDEWEB)

    Tilmes, S.; Garcia, Rolando R.; Kinnison, Douglas E.; Gettelman, A.; Rasch, Philip J.

    2009-06-27

    A coupled chemistry climate model, the Whole Atmosphere Community Climate Model was used to perform a transient climate simulation to quantify the impact of geoengineered aerosols on atmospheric processes. In contrast to previous model studies, the impact on stratospheric chemistry, including heterogeneous chemistry in the polar regions, is considered in this simulation. In the geoengineering simulation, a constant stratospheric distribution of volcanic-sized, liquid sulfate aerosols is imposed in the period 2020–2050, corresponding to an injection of 2 Tg S/a. The aerosol cools the troposphere compared to a baseline simulation. Assuming an Intergovernmental Panel on Climate Change A1B emission scenario, global warming is delayed by about 40 years in the troposphere with respect to the baseline scenario. Large local changes of precipitation and temperatures may occur as a result of geoengineering. Comparison with simulations carried out with the Community Atmosphere Model indicates the importance of stratospheric processes for estimating the impact of stratospheric aerosols on the Earth’s climate. Changes in stratospheric dynamics and chemistry, especially faster heterogeneous reactions, reduce the recovery of the ozone layer in middle and high latitudes for the Southern Hemisphere. In the geoengineering case, the recovery of the Antarctic ozone hole is delayed by about 30 years on the basis of this model simulation. For the Northern Hemisphere, a onefold to twofold increase of the chemical ozone depletion occurs owing to a simulated stronger polar vortex and colder temperatures compared to the baseline simulation, in agreement with observational estimates.

  16. Simplified Modeling of Tropospheric Ozone Formation Considering Alternative Fuels Using

    Directory of Open Access Journals (Sweden)

    Leonardo Aragão Ferreira da Silva

    2014-07-01

    Full Text Available Brazilian cities have been constantly exposed to air quality episodes of high ozone concentrations (O3 . Known for not be emitted directly into the environment, O3 is a result of several chemical reactions of other pollutants emitted to atmosphere. The growth of vehicle fleet and government incentives for using alternative fuels like ethanol and Compressed Natural Gas (CNG are changing the Brazilian Metropolitan Areas in terms of acetaldehyde and formaldehyde emissions, Volatile Organic Compounds (VOC's present in the atmosphere and known to act on the kinetics of ozone. Driven by high concentrations of tropospheric ozone in urban/industry centers and its implications for environment and population health, the target of this work is understand the kinetics of ozone formation through the creation of a mathematical model in FORTRAN 90, describing a system of coupled ordinary differential equations able to represent a simplified mechanism of photochemical reactions in the Brazilian Metropolitan Area. Evaluating the concentration results of each pollutant were possible to observe the precursor’s influence on tropospheric ozone formation, which seasons were more conducive to this one and which are the influences of weather conditions on formation of photochemical smog.

  17. Involvement of gap junction channels in the pathophysiology of migraine with aura

    Directory of Open Access Journals (Sweden)

    Denis eSarrouilhe

    2014-02-01

    Full Text Available Migraine is a common, recurrent and disabling primary headache disorder with a genetic component which affects up to 20 % of the population. One third of all patients with migraine experiences aura, a focal neurological disturbance that manifests itself as visual, sensitive or motor symptoms preceding the headache. In the pathophysiology of migraine with aura, activation of the trigeminovascular system from the meningeal vessels mediates migraine pain via the brainstem and projections ascend to the thalamus and cortex. Cortical spreading depression (CSD was proposed to trigger migraine aura and to activate perivascular trigeminal nerves in the cortex. Quinine, quinidine and the derivative mefloquine are able to inhibit CSD suggesting an involvement of neuronal connexin36 channels in CSD propagation. More recently, CSD was shown to induce headache by activating the trigeminovascular system through the opening of stressed neuronal Pannexin1 channels. A novel benzopyran compound, tonabersat, was selected for clinical trial on the basis of its inhibitory activity on CSD and neurogenic inflammation in animal models of migraine. Interestingly, in the time course of animal model trials, tonabersat was shown to inhibit trigeminal ganglion neuronal-glial cell gap junctions, suggesting that this compound could prevent peripheral sensitization within the ganglion. Three clinical trials aimed at investigating the effectiveness of tonabersat as a preventive drug were negative, and conflicting results were obtained in other trials concerning its ability to relieve attacks. In contrast, in another clinical trial, tonabersat showed a preventive effect on attacks of migraine with aura but had no efficacy on non-aura attacks. Gap junction channels seem to be involved in several ways in the pathophysiology of migraine with aura and emerge as a new promising putative target in treatment of this disorder.

  18. Involvement of gap junction channels in the pathophysiology of migraine with aura

    Science.gov (United States)

    Sarrouilhe, Denis; Dejean, Catherine; Mesnil, Marc

    2014-01-01

    Migraine is a common, recurrent, and disabling primary headache disorder with a genetic component which affects up to 20% of the population. One third of all patients with migraine experiences aura, a focal neurological disturbance that manifests itself as visual, sensitive or motor symptoms preceding the headache. In the pathophysiology of migraine with aura, activation of the trigeminovascular system from the meningeal vessels mediates migraine pain via the brainstem and projections ascend to the thalamus and cortex. Cortical spreading depression (CSD) was proposed to trigger migraine aura and to activate perivascular trigeminal nerves in the cortex. Quinine, quinidine and the derivative mefloquine are able to inhibit CSD suggesting an involvement of neuronal connexin36 channels in CSD propagation. More recently, CSD was shown to induce headache by activating the trigeminovascular system through the opening of stressed neuronal Pannexin1 channels. A novel benzopyran compound, tonabersat, was selected for clinical trial on the basis of its inhibitory activity on CSD and neurogenic inflammation in animal models of migraine. Interestingly, in the time course of animal model trials, tonabersat was shown to inhibit trigeminal ganglion (TGG) neuronal-glial cell gap junctions, suggesting that this compound could prevent peripheral sensitization within the ganglion. Three clinical trials aimed at investigating the effectiveness of tonabersat as a preventive drug were negative, and conflicting results were obtained in other trials concerning its ability to relieve attacks. In contrast, in another clinical trial, tonabersat showed a preventive effect on attacks of migraine with aura but had no efficacy on non-aura attacks. Gap junction channels seem to be involved in several ways in the pathophysiology of migraine with aura and emerge as a new promising putative target in treatment of this disorder. PMID:24611055

  19. Ischemic stroke subtypes and migraine with visual aura in the ARIC study.

    Science.gov (United States)

    Androulakis, X Michelle; Kodumuri, Nishanth; Giamberardino, Lauren D; Rosamond, Wayne D; Gottesman, Rebecca F; Yim, Eunsil; Sen, Souvik

    2016-12-13

    To investigate the association among migraine, ischemic stroke, and stroke subtypes in the Atherosclerosis Risk in Communities (ARIC) study. In this ongoing, prospective, longitudinal community-based cohort study, participants were given an interview ascertaining migraine history in 1993-1995, and were followed for all vascular events, including stroke. All stroke events over the subsequent 20 years were adjudicated and classified into stroke subtypes by standard definitions. Cox proportional hazards models adjusted for stroke risk factors were used to study the relationship between migraine and ischemic stroke, overall, as well as stroke subtypes (cardioembolic, lacunar, or thrombotic). We identified 1,622 migraineurs among 12,758 participants. Mean age of the study population at the 3rd clinical visit was 59 years. When compared to nonheadache participants, there was a significant association between migraine with visual aura and ischemic stroke (hazard ratio [HR] 1.7, 95% confidence interval [CI] 1.2-2.6, p = 0.008). Migraine without visual aura was not significantly associated with ischemic stroke (HR 1.2, CI 1.0-1.8, p = 0.28) when compared to nonheadache participants. Among the 3 subtypes of ischemic stroke evaluated, migraine with visual aura was significantly associated only with cardioembolic stroke (HR 3.7, 95% CI 1.6-8.7, p = 0.003). In participants with migraine with visual aura in late middle age, increased risk of cardioembolic stroke was observed. Migraine with visual aura was linked to increased stroke risk, while migraine without visual aura was not, over the period of 20 years. These results are specific to older migraineurs. © 2016 American Academy of Neurology.

  20. Increased cerebrovascular pCO2 reactivity in migraine with aura--a transcranial Doppler study during hyperventilation

    DEFF Research Database (Denmark)

    Thomsen, L L; Iversen, Helle Klingenberg; Olesen, J

    1995-01-01

    Cerebrovascular reactivity during hypocapnia was tested in 20 migraineurs (8 with aura, 12 without aura) and 30 sex- and age-matched healthy subjects, and during nitroglycerin-induced headache in 12 healthy subjects. Before and during hyperventilation, mean blood-flow velocity (Vmean) in the middle...... cerebral artery was measured with transcranial Doppler. In each subject a pCO2 reactivity index (RI) was calculated as (delta Vmean/baseline Vmean)/delta pCO2. Interictally, patients with migraine with aura showed higher RI (p ... aura did not differ from healthy subjects. Ictal and interictal RIs were similar in 9 patients suffering from migraine without aura. No side-to-side differences were detected in RI. During nitroglycerin-induced headache, the RIs were no different from those recorded during migraine attacks and in non...

  1. Satellite observations and modeling of transport in the upper troposphere through the lower mesosphere during the 2006 major stratospheric sudden warming

    Directory of Open Access Journals (Sweden)

    W. H. Daffer

    2009-07-01

    Full Text Available An unusually strong and prolonged stratospheric sudden warming (SSW in January 2006 was the first major SSW for which globally distributed long-lived trace gas data are available covering the upper troposphere through the lower mesosphere. We use Aura Microwave Limb Sounder (MLS, Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS data, the SLIMCAT Chemistry Transport Model (CTM, and assimilated meteorological analyses to provide a comprehensive picture of transport during this event. The upper tropospheric ridge that triggered the SSW was associated with an elevated tropopause and layering in trace gas profiles in conjunction with stratospheric and tropospheric intrusions. Anomalous poleward transport (with corresponding quasi-isentropic troposphere-to-stratosphere exchange at the lowest levels studied in the region over the ridge extended well into the lower stratosphere. In the middle and upper stratosphere, the breakdown of the polar vortex transport barrier was seen in a signature of rapid, widespread mixing in trace gases, including CO, H2O, CH4 and N2O. The vortex broke down slightly later and more slowly in the lower than in the middle stratosphere. In the middle and lower stratosphere, small remnants with trace gas values characteristic of the pre-SSW vortex lingered through the weak and slow recovery of the vortex. The upper stratospheric vortex quickly reformed, and, as enhanced diabatic descent set in, CO descended into this strong vortex, echoing the fall vortex development. Trace gas evolution in the SLIMCAT CTM agrees well with that in the satellite trace gas data from the upper troposphere through the middle stratosphere. In the upper stratosphere and lower mesosphere, the SLIMCAT simulation does not capture the strong descent of mesospheric CO and H2O values into the reformed vortex; this poor CTM performance in the upper stratosphere and lower mesosphere results

  2. The impact of lightning on tropospheric ozone chemistry using a new global lightning parametrisation

    Science.gov (United States)

    Finney, D. L.; Doherty, R. M.; Wild, O.; Abraham, N. L.

    2016-06-01

    A lightning parametrisation based on upward cloud ice flux is implemented in a chemistry-climate model (CCM) for the first time. The UK Chemistry and Aerosols model is used to study the impact of these lightning nitric oxide (NO) emissions on ozone. Comparisons are then made between the new ice flux parametrisation and the commonly used, cloud-top height parametrisation. The ice flux approach improves the simulation of lightning and the temporal correlations with ozone sonde measurements in the middle and upper troposphere. Peak values of ozone in these regions are attributed to high lightning NO emissions. The ice flux approach reduces the overestimation of tropical lightning apparent in this CCM when using the cloud-top approach. This results in less NO emission in the tropical upper troposphere and more in the extratropics when using the ice flux scheme. In the tropical upper troposphere the reduction in ozone concentration is around 5-10 %. Surprisingly, there is only a small reduction in tropospheric ozone burden when using the ice flux approach. The greatest absolute change in ozone burden is found in the lower stratosphere, suggesting that much of the ozone produced in the upper troposphere is transported to higher altitudes. Major differences in the frequency distribution of flash rates for the two approaches are found. The cloud-top height scheme has lower maximum flash rates and more mid-range flash rates than the ice flux scheme. The initial Ox (odd oxygen species) production associated with the frequency distribution of continental lightning is analysed to show that higher flash rates are less efficient at producing Ox; low flash rates initially produce around 10 times more Ox per flash than high-end flash rates. We find that the newly implemented lightning scheme performs favourably compared to the cloud-top scheme with respect to simulation of lightning and tropospheric ozone. This alternative lightning scheme shows spatial and temporal differences in

  3. EOS Aura's Education and Public Outreach Program - A Lesson for a Scientist.

    Science.gov (United States)

    Hilsenrath, E.

    2002-12-01

    NASA's EOS Aura atmospheric chemistry mission is designed to answer three basic questions about the Earth's atmosphere: a) Is the Earth's ozone layer recovering? b) Is air quality changing? c) How is the Earth's climate changing? The Aura Project agreed to support an ambitious EPO program early in the mission to establish an Aura presence with the public prior to and after launch. The Aura EPO program's overarching objectives is to inform students, our peers, the general public, policy makers and industry. One of my roles as Aura Deputy Project Scientist was to develop a plan, cost, and schedule through launch with these objectives. Our goal was to have the maximum number of outreach contacts for the least cost. This meant taking advantage of well established and proven EPO enterprises. The selected Aura EPO partners include GLOBE, the American Chemical Society, the Smithsonian Institution, Environmental Defense, and NASA's Earth Observatory websites. Managing these tools to convey the Aura message through launch became an over arching task. A Project Scientist's role for a large NASA space mission has many facets and running an EPO program has several challenges. The first success came with bringing on-board experienced Outreach personnel familiar with NASA missions. This step was invaluable in launching Outreach projects since they did not necessarily conform to the NASA way of conducting research and flight missions. "Leveraging" is key element in Outreach programming and we found many avenues among our partners to put this to full use particularly since atmospheric chemistry is an important and sometimes controversial environmental issue. It was gratifying to see, as a scientist, our Outreach contacts get excited about the subject when explained in a personal way. Another important challenge for a scientist is the balance of time spent between research and Outreach. Each requires creativity and dedication of time and both have rewards that are very

  4. Peri-ictal changes of cortical excitability in children suffering from migraine without aura

    DEFF Research Database (Denmark)

    Siniatchkin, Michael; Reich, Anna-Lena; Shepherd, Alex J

    2009-01-01

    regional excitability of the occipital (phosphene threshold [PT] and suppression of visual perception) and motor (resting motor threshold and cortical silent period) cortex in ten children suffering from migraine without aura and ten healthy age-matched controls. Patients were studied 1-2 days before...... aftereffect. Motor cortex excitability was not altered in patients and did not change during the migraine cycle. These findings show that pediatric migraine without aura is associated with a systematic shift in occipital excitability preceding the migraine attack. Similar systematic fluctuations in cortical...

  5. Calcitonin gene-related peptide triggers migraine-like attacks in patients with migraine with aura

    DEFF Research Database (Denmark)

    Hansen, Jakob Møller; Hauge, Anne Werner; Olesen, J.

    2010-01-01

    Calcitonin gene-related peptide (CGRP) is a key molecule in migraine pathogenesis. Intravenous CGRP infusion triggers delayed migraine-like attacks in patients with migraine without aura (MO). In contrast to patients with MO, in prior studies patients with familial hemiplegic migraine (FHM) did...... not report more migraine-like attacks compared to controls. Whether CGRP triggers migraine in patients with typical (non-hemiplegic) migraine with aura is (MA) unknown. In the present study we examined the migraine inducing effect of CGRP infusion in patients suffering from MA and healthy controls....

  6. Carbachol induces headache, but not migraine-like attacks, in patients with migraine without aura

    DEFF Research Database (Denmark)

    Schytz, H W; Wienecke, T; Olesen, J

    2009-01-01

    Schytz HW, Wienecke T, Olesen J & Ashina M. Carbachol induces headache, but not migraine-like attacks, in patients with migraine without aura. Cephalalgia 2009. London. ISSN 0333-1024Carbachol induces headache in healthy subjects, but the migraine eliciting effect of carbachol has not previously...... been studied. We hypothesized that the cholinomimetic agonist carbachol would induce headache and migraine-like attacks in migraineurs. Carbachol (3 microg/kg) or placebo was randomly infused into 18 patients with migraine without aura in a double-blind crossover study. Headache was scored on a verbal...

  7. Calcitonin gene-related peptide triggers migraine-like attacks in patients with migraine with aura

    DEFF Research Database (Denmark)

    Hansen, Jakob Møller; Hauge, Anne Werner; Olesen, Jes

    2010-01-01

    Calcitonin gene-related peptide (CGRP) is a key molecule in migraine pathogenesis. Intravenous CGRP infusion triggers delayed migraine-like attacks in patients with migraine without aura (MO). In contrast to patients with MO, in prior studies patients with familial hemiplegic migraine (FHM) did...... not report more migraine-like attacks compared to controls. Whether CGRP triggers migraine in patients with typical (non-hemiplegic) migraine with aura is (MA) unknown. In the present study we examined the migraine inducing effect of CGRP infusion in patients suffering from MA and healthy controls....

  8. Temporal lobe epilepsy and aura with happiness and pleasure: report of two cases and literature revision

    OpenAIRE

    1994-01-01

    The authors present two cases of temporal lobe epilepsy with happiness and pleasure during the seizure. Discussing the rarity of these clinical findings, the concept of epileptic aura is historically reviewed with special attention to Dostoievski's epilepsy and its descriptions by the medical literature. São apresentados 2 casos de epilepsia do lobo temporal nos quais os pacientes apresentam sensações de alegria e prazer durante a crise. Os autores analisam a evolução do conceito de aura e...

  9. Migraine with aura is associated with an incomplete circle of willis: results of a prospective observational study.

    Directory of Open Access Journals (Sweden)

    Brett Cucchiara

    Full Text Available OBJECTIVE: To compare the prevalence of an incomplete circle of Willis in patients with migraine with aura, migraine without aura, and control subjects, and correlate circle of Willis variations with alterations in cerebral perfusion. METHODS: Migraine with aura, migraine without aura, and control subjects were prospectively enrolled in a 1∶1∶1 ratio. Magnetic resonance angiography was performed to examine circle of Willis anatomy and arterial spin labeled perfusion magnetic resonance imaging to measure cerebral blood flow. A standardized template rating system was used to categorize circle of Willis variants. The primary pre-specified outcome measure was the frequency of an incomplete circle of Willis. The association between circle of Willis variations and cerebral blood flow was also analyzed. RESULTS: 170 subjects were enrolled (56 migraine with aura, 61 migraine without aura, 53 controls. An incomplete circle of Willis was significantly more common in the migraine with aura compared to control group (73% vs. 51%, p = 0.02, with a similar trend for the migraine without aura group (67% vs. 51%, p = 0.08. Using a quantitative score of the burden of circle of Willis variants, migraine with aura subjects had a higher burden of variants than controls (p = 0.02. Compared to those with a complete circle, subjects with an incomplete circle had greater asymmetry in hemispheric cerebral blood flow (p = 0.05. Specific posterior cerebral artery variants were associated with greater asymmetries of blood flow in the posterior cerebral artery territory. CONCLUSIONS: An incomplete circle of Willis is more common in migraine with aura subjects than controls, and is associated with alterations in cerebral blood flow.

  10. Pattern Visual Evoked Potential, Pattern Electroretinogram, and Retinal Nerve Fiber Layer Thickness in Patients with Migraine during and after Aura.

    Science.gov (United States)

    El-Shazly, Amany Abd El-Fattah; Farweez, Yousra Ahmed; Hamdi, Momen Mahmoud; El-Sherbiny, Noha Ezzat

    2017-09-01

    To study pattern visual evoked potential (PVEP), pattern electroretinogram (PERG), and retinal nerve fiber layer (RNFL) thickness in patients with migraine during and after aura. We included 60 eyes of 60 patients with migraine (Group 1) and 30 healthy volunteers (30 eyes) as controls (Group 2). Group 1 was studied twice, during a visual aura (1-a) and in between attacks (1-b). All participants underwent full ophthalmological examination, PVEP, PERG, and optical coherence tomographyOCT imaging of the RNFL thickness for each patient. RNFL thickness was found to be thinner in patients during the aura compared to controls. It increased significantly post-aura but remained lower than the controls. Prolonged P100 latency and decreased amplitude were found in patients during aura compared to controls with significant change in between attacks to values comparable to the controls. We found prolonged N95 latency and decreased amplitude in patients during aura compared to controls with significant change post-aura to values comparable to the controls. There was positive correlation between average RNFL thicknesses and VA and spherical equivalent; but it showed negative correlation with duration of migraine, attack duration, and aura duration. Multiple regression analysis showed that the most important determinants of average RNFL thickness in patients of migraine were attack and aura duration (beta = -0.21 and -0.26 and p = 0.03 and 0.04, respectively). Migraine attacks impose both functional and structural retinal changes. The functional changes are fully reversible after the aura but not the structural ones. So, vigorous prevention of migraine attacks would be protective for retina.

  11. Tropospheric O3 over Indonesia during biomass burning events measured with GOME (Global Ozone Monitoring Experiment) and compared with backtrajectory calculation

    Science.gov (United States)

    Ladstaetter-Weissenmayer, A.; Meyer-Arnek, J.; Burrows, J. P.

    During the dry season, biomass burning is an important source of ozone precursors for the tropical troposphere, and ozone formation can occur in biomass burning plumes originating in Indonesia and northern Australia. Satellite based GOME (Global Ozone Measuring experiment) data are used to characterize the amount of tropospheric ozone production over this region during the El Niño event in September 1997 compared to a so called "normal" year 1998. Large scale biomass burning occurred over Kalimantan in 1997 caused by the absence of the northern monsoon rains, leading to significant increases in tropospheric ozone. Tropospheric ozone was determined from GOME data using the Tropospheric Excess Method (TEM). Backtrajectory calculations show that Indonesia is influenced every summer by the emissions of trace gases from biomass buring over northern Australia. But in 1997 over Indonesia an increasing of tropospheric ozone amounts can be observed caused by the fires over Indonesia itself as well as by northern Australia. The analysis of the measurements of BIBLE-A (Biomass Burning and Lightning Experiment) and using ATSR (Along the Track Scanning Radiometer) data show differences in the view to the intensity of fire counts and therefore in the amount of the emission of precursors of tropospheric ozone comparing September 1997 to September 1998.

  12. Tropospheric ozone as a fungal elicitor

    Indian Academy of Sciences (India)

    Paolo Zuccarini

    2009-03-01

    Tropospheric ozone has been proven to trigger biochemical plant responses that are similar to the ones induced by an attack of fungal pathogens, i.e. it resembles fungal elicitors. This suggests that ozone can represent a valid tool for the study of stress responses and induction of resistance to pathogens. This review provides an overview of the implications of such a phenomenon for basic and applied research. After an introduction about the environmental implications of tropospheric ozone and plant responses to biotic stresses, the biochemistry of ozone stress is analysed, pointing out its similarities with plant responses to pathogens and its possible applications.

  13. Integrity modelling of tropospheric delay models

    Science.gov (United States)

    Rózsa, Szabolcs; Bastiaan Ober, Pieter; Mile, Máté; Ambrus, Bence; Juni, Ildikó

    2017-04-01

    The effect of the neutral atmosphere on signal propagation is routinely estimated by various tropospheric delay models in satellite navigation. Although numerous studies can be found in the literature investigating the accuracy of these models, for safety-of-life applications it is crucial to study and model the worst case performance of these models using very low recurrence frequencies. The main objective of the INTegrity of TROpospheric models (INTRO) project funded by the ESA PECS programme is to establish a model (or models) of the residual error of existing tropospheric delay models for safety-of-life applications. Such models are required to overbound rare tropospheric delays and should thus include the tails of the error distributions. Their use should lead to safe error bounds on the user position and should allow computation of protection levels for the horizontal and vertical position errors. The current tropospheric model from the RTCA SBAS Minimal Operational Standards has an associated residual error that equals 0.12 meters in the vertical direction. This value is derived by simply extrapolating the observed distribution of the residuals into the tail (where no data is present) and then taking the point where the cumulative distribution has an exceedance level would be 10-7.While the resulting standard deviation is much higher than the estimated standard variance that best fits the data (0.05 meters), it surely is conservative for most applications. In the context of the INTRO project some widely used and newly developed tropospheric delay models (e.g. RTCA MOPS, ESA GALTROPO and GPT2W) were tested using 16 years of daily ERA-INTERIM Reanalysis numerical weather model data and the raytracing technique. The results showed that the performance of some of the widely applied models have a clear seasonal dependency and it is also affected by a geographical position. In order to provide a more realistic, but still conservative estimation of the residual

  14. Tropospheric bromine chemistry: implications for present and pre-industrial ozone and mercury

    Directory of Open Access Journals (Sweden)

    J. P. Parrella

    2012-08-01

    Full Text Available We present a new model for the global tropospheric chemistry of inorganic bromine (Bry coupled to oxidant-aerosol chemistry in the GEOS-Chem chemical transport model (CTM. Sources of tropospheric Bry include debromination of sea-salt aerosol, photolysis and oxidation of short-lived bromocarbons, and transport from the stratosphere. Comparison to a GOME-2 satellite climatology of tropospheric BrO columns shows that the model can reproduce the observed increase of BrO with latitude, the northern mid-latitudes maximum in winter, and the Arctic maximum in spring. This successful simulation is contingent on the HOBr + HBr reaction taking place in aqueous aerosols and ice clouds. Bromine chemistry in the model decreases tropospheric ozone mixing ratios by <1–8 nmol mol−1 (6.5% globally, with the largest effects in the northern extratropics in spring. The global mean tropospheric OH concentration decreases by 4%. Inclusion of bromine chemistry improves the ability of global models (GEOS-Chem and p-TOMCAT to simulate observed 19th-century ozone and its seasonality. Bromine effects on tropospheric ozone are comparable in the present-day and pre-industrial atmospheres so that estimates of anthropogenic radiative forcing are minimally affected. Br atom concentrations are 40% higher in the pre-industrial atmosphere due to lower ozone, which would decrease by a factor of 2 the atmospheric lifetime of elemental mercury against oxidation by Br. This suggests that historical anthropogenic mercury emissions may have mostly deposited to northern mid-latitudes, enriching the corresponding surface reservoirs. The persistent rise in background surface ozone at northern mid-latitudes during the past decades could possibly contribute to the observations of elevated mercury in subsurface waters of the North Atlantic.

  15. Tropospheric ozone over Equatorial Africa: regional aspects from the MOZAIC data

    Directory of Open Access Journals (Sweden)

    B. Sauvage

    2005-01-01

    Full Text Available We analyze ozone observations recorded over Equatorial Africa between April 1997 and March 2003 by the MOZAIC programme, providing the first ozone climatology deriving from continental in-situ data over this region. Three-dimensional streamlines strongly suggests connections between the characteristics of the ozone monthly mean vertical profiles, the most persistent circulation patterns in the troposphere over Equatorial Africa (on a monthly basis such as the Harmattan, the African Easterly Jet, the Trades and the regions of ozone precursors emissions by biomass burning. During the biomass burning season in each hemisphere, the lower troposphere exhibits layers of enhanced ozone (i.e. 70 ppbv over the coast of Gulf of Guinea in December-February and 85 ppbv over Congo in June-August. The characteristics of the ozone monthly mean vertical profiles are clearly connected to the regional flow regime determined by seasonal dynamic forcing. The mean ozone profile over the coast of Gulf of Guinea in the burning season is characterized by systematically high ozone below 650hPa ; these are due to the transport by the Harmattan and the AEJ of the pollutants originating from upwind fires. The confinement of high ozone to the lower troposphere is due to the high stability of the Harmattan and the blocking Saharan anticyclone which prevents efficient vertical mixing. In contrast, ozone enhancements observed over Central Africa during the local dry season (June-August are not only found in the lower troposphere but throughout the troposphere. Moreover, this study highlights a connection between the regions of the coast of Gulf of Guinea and regions of Congo to the south that appears on a semi annual basis. Vertical profiles in wet-season regions exhibit ozone enhancements in the lower troposphere due to biomass burning products transport from fires situated in the opposite dry-season hemisphere.

  16. Tropospheric bromine chemistry: implications for present and pre-industrial ozone and mercury

    Directory of Open Access Journals (Sweden)

    J. P. Parrella

    2012-04-01

    Full Text Available We present a new model for the global tropospheric chemistry of inorganic bromine (Bry coupled to oxidant-aerosol chemistry in the GEOS-Chem chemical transport model (CTM. Sources of tropospheric Bry include debromination of sea-salt aerosol, photolysis and oxidation of short-lived bromocarbons, and transport from the stratosphere. Comparison to a GOME-2 satellite climatology of tropospheric BrO columns shows that the model can reproduce the observed increase of BrO with latitude, the northern mid-latitudes maximum in winter, and the Arctic maximum in spring. This successful simulation is contingent on the HOBr + HBr reaction taking place in aqueous aerosols and ice clouds. Bromine chemistry in the model decreases tropospheric ozone concentrations by <1−8 nmol mol−1 (6.5% globally, with the largest effects in the northern extratropics in spring. The global mean tropospheric OH concentration decreases by 4%. Inclusion of bromine chemistry improves the ability of global models (GEOS-Chem and p-TOMCAT to simulate observed 19th-century ozone and its seasonality. Bromine effects on tropospheric ozone are comparable in the present-day and pre-industrial atmospheres so that estimates of anthropogenic radiative forcing are minimally affected. Br atom concentrations are 40% higher in the pre-industrial atmosphere due to lower ozone, which would decrease by a factor of 2 the atmospheric lifetime of elemental mercury against oxidation by Br. This suggests that historical anthropogenic mercury emissions may have mostly deposited to northern mid-latitudes, enriching the corresponding surface reservoirs. The persistent rise in background surface ozone at northern mid-latitudes during the past decades could possibly contribute to the observations of elevated mercury in subsurface waters of the North Atlantic.

  17. Tropospheric bromine chemistry: implications for present and pre-industrial ozone and mercury

    Science.gov (United States)

    Parrella, J. P.; Jacob, D. J.; Liang, Q.; Zhang, Y.; Mickley, L. J.; Miller, B.; Evans, M. J.; Yang, X.; Pyle, J. A.; Theys, N.; Van Roozendael, M.

    2012-08-01

    We present a new model for the global tropospheric chemistry of inorganic bromine (Bry) coupled to oxidant-aerosol chemistry in the GEOS-Chem chemical transport model (CTM). Sources of tropospheric Bry include debromination of sea-salt aerosol, photolysis and oxidation of short-lived bromocarbons, and transport from the stratosphere. Comparison to a GOME-2 satellite climatology of tropospheric BrO columns shows that the model can reproduce the observed increase of BrO with latitude, the northern mid-latitudes maximum in winter, and the Arctic maximum in spring. This successful simulation is contingent on the HOBr + HBr reaction taking place in aqueous aerosols and ice clouds. Bromine chemistry in the model decreases tropospheric ozone mixing ratios by <1-8 nmol mol-1 (6.5% globally), with the largest effects in the northern extratropics in spring. The global mean tropospheric OH concentration decreases by 4%. Inclusion of bromine chemistry improves the ability of global models (GEOS-Chem and p-TOMCAT) to simulate observed 19th-century ozone and its seasonality. Bromine effects on tropospheric ozone are comparable in the present-day and pre-industrial atmospheres so that estimates of anthropogenic radiative forcing are minimally affected. Br atom concentrations are 40% higher in the pre-industrial atmosphere due to lower ozone, which would decrease by a factor of 2 the atmospheric lifetime of elemental mercury against oxidation by Br. This suggests that historical anthropogenic mercury emissions may have mostly deposited to northern mid-latitudes, enriching the corresponding surface reservoirs. The persistent rise in background surface ozone at northern mid-latitudes during the past decades could possibly contribute to the observations of elevated mercury in subsurface waters of the North Atlantic.

  18. Injection of lightning-produced NOx, water vapor, wildfire emissions, and stratospheric air to the UT/LS as observed from DC3 measurements

    Science.gov (United States)

    Huntrieser, H.; Lichtenstern, M.; Scheibe, M.; Aufmhoff, H.; Schlager, H.; Pucik, T.; Minikin, A.; Weinzierl, B.; Heimerl, K.; Pollack, I. B.; Peischl, J.; Ryerson, T. B.; Weinheimer, A. J.; Honomichl, S.; Ridley, B. A.; Biggerstaff, M. I.; Betten, D. P.; Hair, J. W.; Butler, C. F.; Schwartz, M. J.; Barth, M. C.

    2016-06-01

    During the Deep Convective Clouds and Chemistry (DC3) experiment in summer 2012, airborne measurements were performed in the anvil inflow/outflow of thunderstorms over the Central U.S. by three research aircraft. A general overview of Deutsches Zentrum für Luft- und Raumfahrt (DLR)-Falcon in situ measurements (CO, O3, SO2, CH4, NO, NOx, and black carbon) is presented. In addition, a joint flight on 29 May 2012 in a convective line of isolated supercell storms over Oklahoma is described based on Falcon, National Science Foundation/National Center for Atmospheric Research Gulfstream-V (NSF/NCAR-GV), and NASA-DC8 trace species in situ and lidar measurements. During DC3 some of the largest and most destructive wildfires in New Mexico and Colorado state's history were burning, which strongly influenced air quality in the DC3 thunderstorm inflow and outflow region. Lofted biomass burning (BB) plumes were frequently observed in the mid- and upper troposphere (UT) in the vicinity of deep convection. The impact of lightning-produced NOx (LNOx) and BB emissions was analyzed on the basis of mean vertical profiles and tracer-tracer correlations (CO-NOx and O3-NO). On a regular basis DC3 thunderstorms penetrated the tropopause and injected large amounts of LNOx into the lower stratosphere (LS). Inside convection, low O3 air (~80 nmol mol-1) from the lower troposphere was rapidly transported to the UT/LS region. Simultaneously, O3-rich stratospheric air masses (~100-200 nmol mol-1) were present around and below the thunderstorm outflow and enhanced UT-O3 mixing ratios significantly. A 10 year global climatology of H2O data from the Aura Microwave Limb Sounder confirmed that the Central U.S. is a preferred region for convective injection into the LS.

  19. VOLATILE ORGANIC COMPOUND EMISSION RATES FROM MIXED DECIDUOUS AND CONIFEROUS FORESTS IN NORTHERN WISCONSIN, USA

    Science.gov (United States)

    Biogenic emissions of volatile organic compounds (VOC) from forests play an important role in regulating the atmospheric trace gas composition including global tropospheric ozone concentrations. However, more information is needed on VOC emission rates from different forest regio...

  20. Visual migraine aura with or without headache: association with right to left shunt and assessment following transcutaneous closure

    Directory of Open Access Journals (Sweden)

    Mojadidi MK

    2012-07-01

    Full Text Available M Khalid Mojadidi,1 Hamidreza Khessali,1 Rubine Gevorgyan,1 Ralph D Levinson,2 Jonathan M Tobis11Division of Interventional Cardiology, David Geffen School of Medicine, University of California at Los Angeles, 2Division of Comprehensive Ophthalmology and Ocular Inflammatory Disease Center, Jules Stein Eye Institute, University of California at Los Angeles, Los Angeles, CA, USABackground: Right to left shunting, usually caused by a patent foramen ovale (PFO, is associated with migraine and visual aura. It is unknown if patients who present with visual aura without headache behave similarly to those experiencing typical migraine headache with aura. The purpose of this study was to assess the prevalence of right to left shunting in patients who present with migraine aura without headache and evaluate the response to PFO closure.Methods: The records of patients referred to the Interventional Cardiology program at the University of California at Los Angeles for suspected intracardiac right to left shunt were reviewed. Individuals with visual auras with or without migraine headaches were divided into three groups: group A (aura + migraine, migraine aura during or within 60 minutes of headache; group B (migraine aura unrelated to headache, migraine aura and headache temporally unrelated; and group C (migraine aura only, isolated migraine visual aura without a history of headaches. The presence of right to left shunt was assessed using transcranial Doppler with an agitated saline test. PFO closure was performed in 80 patients. Residual headache and migraine visual aura were assessed 3 and 12 months after the procedure. The control group consisted of 200 patients referred for diagnostic cardiac catheterization.Results: Of 590 referred patients, 225 had migraine visual aura with or without headache. The prevalence of right to left shunt was similar (P = 0.66 in groups B (21/29, 72% and C (14/21, 67%. Group A patients had a higher prevalence of right to

  1. CHEMICALS COMPOUNDS EMITTED BY COMMERCIAL PLANTATION AND THEIR RELATIONSHIP WITH THE LOCAL TROPOSPHERIC CHEMISTRY

    OpenAIRE

    Ana Paula dos Santos Zepka

    2014-01-01

    Eucalyptus stands are among the most commonly used species for reforestation in the “Vale do Paraíba”. The objective of this study was to detect for the first time isoprene emission by commercial plantations of eucalyptus and relate it to the local tropospheric ozone, thus evaluating the environmental impact of these forests. The samples were collected from denuders of Air Toxics analyzed by gas chromatography through thermal desorption. Ozone was monitored by UV Photometric O3 Analyzer Model...

  2. Characterization of MJO-Related Upper Tropospheric Hydrological Processes using MLS

    Science.gov (United States)

    Schwartz, Michael J.; Waliser, Duane E.; Tian, Baijun; Wu, Dong L.; Jiang, Jonathan H.; Read, William G.

    2008-01-01

    This study quantifies Madden-Julian Oscillation (MJO)- related hydrological variability in the upper troposphere/ lower stratosphere (UT/LS) using Aura Microwave Limb Sounder (MLS) cloud ice water content (IWC) and water vapor (H2O). In a composite of six boreal-winter MJO events, the UT/LS IWC anomaly is strongly positively correlated with the convection (TRMM rainfall) anomaly. IWC anomalies range from +/-2 mg/cu m at 215 hPa to +/-0.08 mg/cu m at 100 hPa. The UT/LS H2O anomaly has an eastward-tilting structure similar to the previous-documented temperature structure, but the H2O maximum lags the temperature maximum by about a week. The H2O anomaly is positively correlated with the convection anomaly in the UT (261 hPa) and LS (68 hPa) but negatively correlated with the convection anomaly near the tropopause (100 hPa). This analysis provides a multi-parameter construct useful in validating and improving the parameterization of convection, clouds and cloud microphysics in MJO modeling.

  3. A Comparison of Different Methods in the Estimations of Source-Receptor Relationships for Tropospheric Ozone

    Science.gov (United States)

    Nagashima, T.; Ohara, T.; Sudo, K.; Akimoto, H.

    2010-12-01

    Tropospheric ozone (O3) is an air pollutant chemically created in the atmosphere from its precursors (NOx, CO, and VOCs) which are emitted from anthropogenic activities like industrial activities, electrical power generation and road transportation and has detrimental impacts on human health, agricultural crops, and ecosystems. The growing anthropogenic activities around the world have been raising problems that the long-range (intercontinental scale) transported O3 affect the air quality in far remote regions from its source region. Therefore, it is important to quantitatively estimate the proportion of O3 over a receptor region that is attributable to a source region, the so-called source-receptor (S-R) relationship for tropospheric O3. The S-R relationship for tropospheric O3 has been widely investigated in recent years mainly by using chemical transport models. Although those efforts have greatly progressed the understanding of the S-R relationship for tropospheric O3, there still exist uncertainties in the estimation of it. The difference of the methodology to estimate the S-R relationship is one of the main causes of the uncertainties. Here, we compare the S-R relationships for tropospheric O3 estimated by two different methods: tracer tagging method (TTM) and emission sensitivity method (ESM). We use the same chemical transport model (CHASER), emission data, and settings for source and receptor regions for both methods. The difference in the contribution of a source region estimated by both methods becomes largest in that source region, for instance, the contribution of China estimated by two methods differs largest in China itself. The contribution estimated by TTM is generally larger than that by ESM in that source region. However, this relationship is reversed outside that source region. These differences between TTM and ESM tend to increase in summer.

  4. MAX-DOAS tropospheric nitrogen dioxide column measurements compared with the Lotos-Euros air quality model

    NARCIS (Netherlands)

    Vlemmix, T.; Eskes, H.J.; Piters, A.J.M.; Schaap, M.; Sauter, F.J.; Kelder, H.; Levelt, P.F.

    2015-01-01

    A 14-month data set of MAX-DOAS (Multi-Axis Differential Optical Absorption Spectroscopy) tropospheric NO2 column observations in De Bilt, the Netherlands, has been compared with the regional air quality model Lotos-Euros. The model was run on a 7×7 km2 grid, the same resolution as the emission inve

  5. Impact of land convection on troposphere-stratosphere exchange in the tropics

    Directory of Open Access Journals (Sweden)

    P. Ricaud

    2007-11-01

    Full Text Available The mechanism of troposphere-stratosphere exchange in the tropics was investigated from space-borne observations of the horizontal distributions of tropospheric-origin long-lived species, nitrous oxide (N2O, methane (CH4 and carbon monoxide (CO, from 150 to 70 hPa in March-April-May by the ODIN/Sub-Millimeter Radiometer (SMR, the Upper Atmosphere Research Satellite (UARS/Halogen Occultation Experiment (HALOE and the TERRA/Measurements Of Pollution In The Troposphere (MOPITT instruments in 2002–2004, completed by recent observations of the AURA/Microwave Limb Sounder (MLS instrument during the same season in 2005. The vertical resolution of the satellite measurements ranges from 2 to 4 km. The analysis has been performed on isentropic surfaces: 400 K (lower stratosphere for all the species and 360 K (upper troposphere only for CO. At 400 K (and 360 K for CO, all gases show significant longitudinal variations with peak-to-trough values of ~5–11 ppbv for N2O, 0.07–0.13 ppmv for CH4, and ~10 ppbv for CO (~40 ppbv at 360 K. The maximum amounts are primarily located over Africa and, depending on the species, secondary more or less pronounced maxima are reported above northern South America and South-East Asia. The lower stratosphere over the Western Pacific deep convective region where the outgoing longwave radiation is the lowest, the tropopause the highest and the coldest, appears as a region of minimum concentration of tropospheric trace species. The possible impact on trace gas concentration at the tropopause of the inhomogeneous distribution and intensity of the sources, mostly continental, of the horizontal and vertical transports in the troposphere, and of cross-tropopause transport was explored with the MOCAGE Chemistry Transport Model. In the simulations, significant longitudinal variations were found on the medium-lived CO (2-month lifetime with peak-to-trough value of ~20 ppbv at 360 K and

  6. TROPOSPHERIC AEROSOL PROGRAM, PROGRAM PLAN, MARCH 2001

    Energy Technology Data Exchange (ETDEWEB)

    SCHWARTZ,S.E.; LUNN,P.

    2001-03-01

    The goal of Tropospheric Aerosol Program (TAP) will be to develop the fundamental scientific understanding required to construct tools for simulating the life cycle of tropospheric aerosols--the processes controlling their mass loading, composition, and microphysical properties, all as a function of time, location, and altitude. The TAP approach to achieving this goal will be by conducting closely linked field, modeling, laboratory, and theoretical studies focused on the processes controlling formation, growth, transport, and deposition of tropospheric aerosols. This understanding will be represented in models suitable for describing these processes on a variety of geographical scales; evaluation of these models will be a key component of TAP field activities. In carrying out these tasks TAP will work closely with other programs in DOE and in other Federal and state agencies, and with the private sector. A forum to directly work with our counterparts in industry to ensure that the results of this research are translated into products that are useful to that community will be provided by NARSTO (formerly the North American Research Strategy on Tropospheric Ozone), a public/private partnership, whose membership spans government, the utilities, industry, and university researchers in Mexico, the US, and Canada.

  7. New Directions: Watching over tropospheric hydroxyl (OH)

    NARCIS (Netherlands)

    Lelieveld, J.; Brenninkmeijer, C.A.M.; Joeckel, P.; Isaksen, I.S.A.; Krol, M.C.; Mak, J.E.; Dlugokencky, E.; Montzka, S.A.; Novelli, P.C.; Peters, W.; Tans, P.P.

    2006-01-01

    Mean tropospheric hydroxyl radical (OH) abundance is often used as a measure of the oxidation capacity (or “self-cleansing”) of the atmosphere. The primary mechanism by which atmospheric pollutant gases are removed from the atmosphere is initiated by the reaction with OH. As a result, large interann

  8. The Impact of the South Asia High Bimodality on the Chemical Composition of the Upper Troposphere and Lower Stratosphere

    Institute of Scientific and Technical Information of China (English)

    YAN Ren-Chang; BIAN Jian-Chun; FAN Qiu-Jun

    2011-01-01

    The South Asia High (SAH) is the dominant feature of the circulation in the upper troposphere and lower stratosphere (UTLS) during the boreal summer, and the upper tropospheric anticyclonic circulation extends into the lower stratosphere. The preferred locations of the center of the SAH occur in two different regions, and the center can be located over the Iranian Plateau or over the Tibetan Plateau. This bimodality has an impact on the distribution of chemical constituents in the UTLS region. We analyzed water vapor (H20), carbon monoxide (CO), and ozone (03) data derived from the Aura Microwave Limb Sounder (MLS) and total column ozone data from the Ozone Monitoring Instrument (OMI). For the Iranian Plateau mode of the SAH, the tropospheric tracers exhibited a positive anomaly over the Iranian Plateau and a negative anomaly over the Tibetan Plateau, whereas the stratospheric tracer exhibited a negative and a positive anomaly over the Iranian Plateau and the Tibetan Plateau, respectively. For the Tibetan Plateau mode, however, the distribution of the anomaly was the reverse of that found for the chemical species in the UTLS region. Furthermore, the locations of the extrema within the anomaly seemed to differ across chemical species. The anomaly extrema for H20 occurred in the vicinity of the SAH ridgeline, whereas CO and O3 exhibited a northward shift of 4-8 degrees. These impacts of the variation in the SAH on the chemical constitutes in the UTLS region can be attributed in part to the dynamical structure delineated by the tropopause field and the temperature field at 100 hPa.

  9. Eficácia de três drogas sobre a aura migranosa: um estudo randomizado placebo controlado Efficacy of three drugs in the treatment of migrainous aura: a randomized, placebo-controlled study

    Directory of Open Access Journals (Sweden)

    Marcelo E. Bigal

    2002-06-01

    Full Text Available A despeito da enorme quantidade de pesquisas referentes à classificação, epidemiologia, diagnóstico, fisiopatologia e tratamento da migrânea, a aura migranosa permanece bem menos estudada. O objetivo do presente estudo é, portanto, verificar a evolução da aura em pacientes submetidos a placebo e a três diferentes drogas disponíveis em unidades públicas de saúde brasileiras. Foram estudados 86 pacientes em vigência de crise de migrânea com aura, apresentando aura no momento da randomização. Após a randomização os pacientes recebiam uma das seguintes substâncias, por via endovenosa: placebo, dipirona, clorpromazina, sulfato de magnésio. O sulfato de magnésio foi superior ao placebo (p In spite of the enormous amount of research regarding classification, epidemiology, diagnosis, pathophisiology and treatment of migraines, aura, one of its hallmarks, stays much less studied. The objective of this study is, therefore, to evaluate the evolution of aura in patients submitted to placebo and three different drugs available in Brazilian public health units. We studied 86 patients during an acute migrainous attack, with aura at the moment of the evaluation. Patients were randomized to receive one of the following substances, in a parenteral route: placebo, dipyrone, chlorpromazine and magnesium sulphate. Magnesium sulphate was superior to placebo (p <0,05 30 and 60 minutes after its administration. Dipyrone and chlorpromazine reduced the duration of the aura, when compared to placebo, 60 minutes following their administration. Our findings make possible some speculations about the pathophisiology of migraine, as well as about the therapeutic approach of patients presenting migrainous aura.

  10. Methane Sensitivity to Perturbations in Tropospheric Oxidizing Capacity

    Science.gov (United States)

    Yegorova, Elena; Duncan, Bryan

    2011-01-01

    Methane is an important greenhouse gas and has a 25 times greater global warming potential than CO2 on a century timescale. Yet there are considerable uncertainties in the magnitude and variability of its sources and sinks. The response of the coupled non-linear methane-carbon monoxide-hydroxyl radical (OH) system is important in determining the tropospheric oxidizing capacity. Using the NASA Goddard Earth Observing System, Version 5 (GEOS-5) chemistry climate model, we study the response of methane to perturbations of OH and wetland emissions. We use a computationally-efficient option of the GEOS-5 CCM that includes an OH parameterization that accurately represents OH predicted by a full chemical mechanism. The OH parameterization allows for studying non-linear CH4-CO-OH feedbacks in computationally fast sensitivity experiments. We compare our results with surface observations (GMD) and discuss the range of uncertainty in OH and wetland emissions required to bring modeling results in better agreement with surface observations. Our results can be used to improve projections of methane emissions and methane growth.

  11. Mid-latitude tropospheric ozone columns from the MOZAIC program: climatology and interannual variability

    Directory of Open Access Journals (Sweden)

    R. M. Zbinden

    2006-01-01

    Full Text Available Several thousands of ozone vertical profiles collected in the course of the MOZAIC programme (Measurements of Ozone, Water Vapour, Carbon Monoxide and Nitrogen Oxides by In-Service Airbus Aircraft from August 1994 to February 2002 are investigated to bring out climatological and interannual variability aspects. The study is centred on the most frequently visited MOZAIC airports, i.e. Frankfurt (Germany, Paris (France, New York (USA and the cluster of Tokyo, Nagoya and Osaka (Japan. The analysis focuses on the vertical integration of ozone from the ground to the dynamical tropopause and the vertical integration of stratospheric-origin ozone throughout the troposphere. The characteristics of the MOZAIC profiles: frequency of flights, accuracy, precision, and depth of the troposphere observed, are presented. The climatological analysis shows that the Tropospheric Ozone Column (TOC seasonal cycle ranges from a wintertime minimum at all four stations to a spring-summer maximum in Frankfurt, Paris, and New York. Over Japan, the maximum occurs in spring presumably because of the earlier springtime sun. The incursion of monsoon air masses into the boundary layer and into the mid troposphere then steeply diminishes the summertime value. Boundary layer contributions to the TOC are 10% higher in New York than in Frankfurt and Paris during spring and summer, and are 10% higher in Japan than in New York, Frankfurt and Paris during autumn and early spring. Local and remote anthropogenic emissions, and biomass burning over upstream regions of Asia may be responsible for the larger low- and mid-tropospheric contributions to the tropospheric ozone column over Japan throughout the year except during the summer-monsoon season. A simple Lagrangian analysis has shown that a minimum of 10% of the TOC is of stratospheric-origin throughout the year. Investigation of the short-term trends of the TOC over the period 1995–2001 shows a linear increase 0.7%/year in

  12. Evaluation of the new UKCA climate-composition model – Part 2: The Troposphere

    Directory of Open Access Journals (Sweden)

    F. M. O'Connor

    2013-03-01

    Full Text Available In this paper, we present a description of the tropospheric chemistry component of the UK Chemistry and Aerosols (UKCA model which has been coupled to the Met Office Hadley Centre's HadGEM family of climate models. We assess the model's transport and scavenging processes, in particular focussing on convective transport, boundary layer mixing, wet scavenging and inter-hemispheric exchange. Simulations with UKCA of the short-lived radon tracer suggest that modelled distributions are comparable to those of other models and the comparison with observations indicate that apart from a few locations, boundary layer mixing and convective transport are effective in the model as a means of vertically re-distributing surface emissions of radon. Comparisons of modelled lead tracer concentrations with observations suggest that UKCA captures surface concentrations in both hemispheres very well although there is a tendency to underestimate the observed geographical and interannual variability in the Northern Hemisphere. In particular, UKCA replicates the shape and absolute concentrations of observed lead profiles, a key test in the evaluation of a model's wet scavenging scheme. The timescale for inter-hemispheric transport, calculated in the model using a simple krypton tracer experiment, does appear to be long relative to other models and could indicate deficiencies in tropical deep convection and/or insufficient boundary layer mixing. We also describe the main components of the tropospheric chemistry and evaluate it against observations and other tropospheric chemistry models. In particular, from a climate forcing perspective, present-day observed surface methane concentrations and tropospheric ozone concentrations are reproduced very well by the model, thereby making it suitable for long centennial integrations as well as studies of biogeochemical feedbacks. Results from both historical and future simulations with UKCA tropospheric chemistry are presented

  13. Is SOD2 Ala16Val polymorphism associated with migraine with aura phenotype?

    Science.gov (United States)

    Palmirotta, Raffaele; Barbanti, Piero; De Marchis, Maria Laura; Egeo, Gabriella; Aurilia, Cinzia; Fofi, Luisa; Ialongo, Cristiano; Valente, Maria Giovanna; Ferroni, Patrizia; Della-Morte, David; Guadagni, Fiorella

    2015-01-20

    Several studies suggest a role of oxidative stress in the physiopathology of migraine, particularly in the form with aura. In a case-control study, we investigated the association between migraine and superoxide dismutase 1 (SOD1) and superoxide dismutase 2 (SOD2) genes in a cohort of 490 consecutive unrelated Caucasian migraineurs (migraine with aura [MwA], n=107; migraine without aura [MwoA], n=246; chronic migraine [CM], n=137) and 246 healthy controls recruited at our Headache and Pain Unit and stored in the Interinstitutional Multidisciplinary BioBank (BioBIM). Migraine phenotype was carefully detailed using face-to-face interviews. We examined polymorphisms of SOD1 gene (A/C substitution-rs2234694) and SOD2 gene (C/T transition-rs4880-Ala16Val). The rs4880 TT (Val/Val) genotype was associated (p=0.042) with the presence of unilateral cranial autonomic symptoms (UAs) in MwA patients. We also found a mild correlation between SOD2 rs4880 genotype and the type of acute migraine treatment (p=0.048) in MwA patients. Our findings suggest that SOD2 is a disease-modifier gene influencing oxidative mechanisms in MwA. These observations lead to the hypothesis that SOD2 polymorphism may cause a defective control of the oxidative phenomena linked to cortical spreading depression, the neurophysiological hallmark of migraine aura, causing an overstimulation of trigeminal neurons and UAs triggering.

  14. Scent of aura? Clinical features of olfactory hallucinations during a migraine attack (OHM).

    Science.gov (United States)

    Mainardi, Federico; Rapoport, Alan; Zanchin, Giorgio; Maggioni, Ferdinando

    2017-02-01

    Introduction Olfactory hallucination during a migraine attack (OHM) is a rare phenomenon. At present, it is not considered a manifestation of migraine aura. Material and methods The clinical features of OHM were collected in 11 patients. Results Of the 11 patients, 10 had migraine without aura and one migraine with aura associated with OHM. Mean age at onset of headache and at appearance of OHM were respectively 17.8 and 32.3 years. Migraine average frequency was 3.9 attacks/month, 19% of them being associated with OHM. The temporal pattern of OHM maintained the same characteristics in the different attacks. OHM onset was described as sudden ( n = 5), gradual ( n = 3), initially sudden and then gradual ( n = 2), or developing in a few seconds ( n = 1). In most of the cases ( n = 8) OHM lasted from 3 to 10 minutes; it persisted during the pain phase (2-24 hours) in only three patients. The type of the perceived smell was invariably constant in nine patients. Conclusion OHM features fulfilled the ICHD-III beta criteria for typical aura.

  15. Aura OMI observations of regional SO2 and NO2 pollution changes from 2005 to 2015

    NARCIS (Netherlands)

    Krotkov, Nickolay A.; McLinden, Chris A.; Li, Can; Lamsal, Lok N.; Celarier, Edward A.; Marchenko, Sergey V.; Swartz, William H.; Bucsela, Eric J.; Joiner, Joanna; Duncan, Bryan N.; Boersma, Folkert; Veefkind, J.P.; Levelt, Pieternel F.; Fioletov, Vitali E.; Dickerson, Russell R.; He, Hao; Lu, Zifeng; Streets, David G.

    2016-01-01

    The Ozone Monitoring Instrument (OMI) onboard NASA's Aura satellite has been providing global observations of the ozone layer and key atmospheric pollutant gases, such as nitrogen dioxide (NO2) and sulfur dioxide (SO2), since October 2004. The data products from the same instrument provide consis

  16. Migraine without aura is not associated with incomplete circle of Willis

    DEFF Research Database (Denmark)

    Ezzatian-Ahar, Shabnam; Amin, Faisal Mohammad; Obaid, Hayder Ghani

    2014-01-01

    the prevalence of incomplete circle of Willis in migraineurs and controls. In the present study we compared the prevalence of incomplete circle of Willis in female migraine patients without aura to female healthy non-migraine controls.Using 3-Tesla magnetic resonance angiography we recorded three...

  17. Aura OMI observations of regional SO2 and NO2 pollution changes from 2005 to 2015

    NARCIS (Netherlands)

    Krotkov, Nickolay A.; McLinden, Chris A.; Li, Can; Lamsal, Lok N.; Celarier, Edward A.; Marchenko, Sergey V.; Swartz, William H.; Bucsela, Eric J.; Joiner, Joanna; Duncan, Bryan N.; Boersma, Folkert; Veefkind, J.P.; Levelt, Pieternel F.; Fioletov, Vitali E.; Dickerson, Russell R.; He, Hao; Lu, Zifeng; Streets, David G.

    2016-01-01

    The Ozone Monitoring Instrument (OMI) onboard NASA's Aura satellite has been providing global observations of the ozone layer and key atmospheric pollutant gases, such as nitrogen dioxide (NO2) and sulfur dioxide (SO2), since October 2004. The data products from the same instrument provide

  18. Transient Splenial Lesion of the Corpus Callosum Related to Migraine with Aura in a Pediatric Patient.

    Science.gov (United States)

    Ünver, Olcay; Kutlubay, Büşra; Besci, Tolga; Ekinci, Gazanfer; Baltacıoğlu, Feyyaz; Türkdoğan, Dilşad

    Transient splenial lesions of the corpus callosum are rare radiological findings first described in association with epilepsy, antiepileptic drugs and viral encephalitis. However, subsequently more cases were described associated with diverse clinical conditions. We describe a 13-year-old girl suffering from migraine with aura presenting with headache, right-sided hemiparesis and encephalopathy. Brain magnetic resonance imaging revealed an ovoid lesion in the splenium of the corpus callosum. The patient's neurological symptoms resolved within 3 days without therapy and the lesion disappeared in follow up magnetic resonance images obtained 3 weeks after the onset of the symptoms. Migraine with aura was considered to be the cause of the lesion. To our knowledge the present case is the first report of a pediatric patient with a diagnosis of migraine with aura presenting with hemiparesis and encephalopathy. A diagnosis of transient lesion of the corpus callosum should be suspected in patients with migraine with aura presenting with hemiparesis and encephalopathy. A mild course and a good prognosis might be expected in the presence of a splenial lesion of the corpus callosum.

  19. Inimlik eksitus Lätis saatis kontrolli kõik Aura mahlajoogid / Hindrek Riikoja

    Index Scriptorium Estoniae

    Riikoja, Hindrek

    2006-01-01

    Tartu Õlletehase liiga suure säilitusaine sisalduse tõttu Lätis müügilt kõrvaldatud Aura Arcticu mahlajoogid tõid kaasa kogu tootesarja ulatusliku kontrolli. Rohkem eksimusi uuring ei tuvastanud. Lisa: Bensoehape

  20. Vitamin supplementation as possible prophylactic treatment against migraine with aura and menstrual migraine.

    Science.gov (United States)

    Shaik, Munvar Miya; Gan, Siew Hua

    2015-01-01

    Migraine is the most common form of headache disorder globally. The etiology of migraine is multifactorial, with genetic components and environmental interactions considered to be the main causal factors. Some researchers postulate that deficits in mitochondrial energy reserves can cause migraine or an increase in homocysteine levels can lead to migraine attacks; therefore, vitamins could play a vital role in migraine prevention. For instance, riboflavin influences mitochondrial dysfunction and prevents migraine. Genes such as flavoenzyme 5,10-methylenetetrahydrofolate reductase (MTHFR), especially the C677T variant, have been associated with elevated plasma levels of homocysteine and migraine with aura. Homocysteine catalyzation requires the presence of vitamins B6, B12, and folic acid, which can decrease the severity of migraine with aura, making these vitamins potentially useful prophylactic agents for treating migraine with aura. Menstrual migraine, on the other hand, is associated with increased prostaglandin (PG) levels in the endometrium, indicating a role for vitamin E, which is an anti-PG. Vitamin C can also be used as a scavenger of reactive oxygen species for treating neurogenic inflammation in migraine patients. This paper reviews possible therapies based on vitamin supplementation for migraine prophylaxis, focusing on migraine with aura and menstrual migraine.

  1. Prostaglandin (E2) induces immediate migraine-like attack in migraine patients without aura

    DEFF Research Database (Denmark)

    Antonova, Maria; Wienecke, Troels; Olesen, Jes

    2012-01-01

    without aura were randomly allocated to receive 0.4 µg/kg/min PGE(2) (Prostin®E2, dinoprostone) or placebo over 25 minutes in a two-way, crossover study. Headache intensity was recorded on a verbal rating scale, middle cerebral artery blood flow velocity (V(MCA)) was measured by transcranial Doppler (TCD...

  2. Inimlik eksitus Lätis saatis kontrolli kõik Aura mahlajoogid / Hindrek Riikoja

    Index Scriptorium Estoniae

    Riikoja, Hindrek

    2006-01-01

    Tartu Õlletehase liiga suure säilitusaine sisalduse tõttu Lätis müügilt kõrvaldatud Aura Arcticu mahlajoogid tõid kaasa kogu tootesarja ulatusliku kontrolli. Rohkem eksimusi uuring ei tuvastanud. Lisa: Bensoehape

  3. Intact neurovascular coupling during executive function in migraine without aura: interictal near-infrared spectroscopy study

    DEFF Research Database (Denmark)

    Schytz, H W; Ciftçi, K; Akin, A

    2010-01-01

    An altered neurovascular coupling has been proposed in migraine. We aimed to investigate neurovascular coupling during a mental task interictally in patients with migraine without aura (MO) by near-infrared spectroscopy (NIRS). Twelve migraineurs and 12 healthy controls were included. Using NIRS...

  4. Aqua-Aura QuickDAM (QDAM) 2.0 Ops Concept

    Science.gov (United States)

    Nidhiry, John

    2015-01-01

    The presentation describes the Quick Debris Avoidance Maneuver (QDAM) 2.0 process used the Aqua and Aura flight teams to (a) reduce the work load and dependency on staff and systems; (b) reduce turn-around time and provide emergency last minute capabilities; and (c) increase burn parameter flexibility. The presentation also compares the QDAM 2.0 process to previous approaches.

  5. Addenbrooke's cognitive examination test for brief cognitive assessment of adolescents suffering from migraine with aura.

    Science.gov (United States)

    Petrusic, Igor; Pavlovski, Vera; Savkovic, Zorica; Vucinic, Dragana; Filipovic, Branislav; Jancic, Jasna

    2017-03-01

    The aim of this study was to assess the role of the Addenbrooke's cognitive examination test (ACE-R) in the evaluation of cognitive status in migraineurs interictally. A total of 44 adolescent patients and 44 healthy controls, matched by age and gender, have undergone ACE-R testing. Migraineurs were additionally questioned about migraine aura features and presence of higher cortical dysfunctions (HCD) during an aura. According to the questionnaire results, patients were subsequently divided into HCD and Non-HCD group. ACE-R scores of migraine patients were significantly lower than in healthy controls (93.68 ± 3.64 vs 96.91 ± 2.49; t = 4.852, p aura. Also, our study has revealed that the ACE-R test is an easily administered test for brief assessment of cognitive status in migraineurs. Future perspectives could be further evaluation of ACE-R test in larger sample size and the impact of migraine with aura on cognitive function in adolescents.

  6. Transient Splenial Lesion of the Corpus Callosum Related to Migraine with Aura in a Pediatric Patient

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    Olcay Ünver

    2016-08-01

    Full Text Available Background: Transient splenial lesions of the corpus callosum are rare radiological findings first described in association with epilepsy, antiepileptic drugs and viral encephalitis. However, subsequently more cases were described associated with diverse clinical conditions. Case report: We describe a 13-year-old girl suffering from migraine with aura presenting with headache, right-sided hemiparesis and encephalopathy. Brain magnetic resonance imaging revealed an ovoid lesion in the splenium of the corpus callosum. The patient’s neurological symptoms resolved within 3 days without therapy and the lesion disappeared in follow up magnetic resonance images obtained 3 weeks after the onset of the symptoms. Results: Migraine with aura was considered to be the cause of the lesion. To our knowledge the present case is the first report of a pediatric patient with a diagnosis of migraine with aura presenting with hemiparesis and encephalopathy. Conclusions: A diagnosis of transient lesion of the corpus callosum should be suspected in patients with migraine with aura presenting with hemiparesis and encephalopathy. A mild course and a good prognosis might be expected in the presence of a splenial lesion of the corpus callosum.

  7. A case of strictly unilateral migraine without aura transformed in an episodic hemicrania continua.

    Science.gov (United States)

    Terlizzi, Rossana; Cevoli, Sabina; Nicodemo, Marianna; Pierangeli, Giulia; Grimaldi, Daniela; Cortelli, Pietro

    2011-02-01

    According to the diagnostic criteria of International Headache Society classification, hemicrania continua is a strictly unilateral continuous headache of moderate intensity with painful exacerbations associated with ipsilateral autonomic signs without pain-free periods. We report a case of a 42-year-old woman suffered of a remitting form of hemicrania continua evolved from a strictly unilateral migraine without aura.

  8. Migraine with aura and risk of silent brain infarcts and white matter hyperintensities

    DEFF Research Database (Denmark)

    Gaist, David; Garde, Ellen; Blaabjerg, Morten;

    2016-01-01

    identified through the population-based Danish Twin Registry. Based on questionnaire responses, twins were invited to participate in a telephone-based interview conducted by physicians. Headache diagnoses were established according to the International Headache Society criteria. Cases with migraine with aura...

  9. Vitamin Supplementation as Possible Prophylactic Treatment against Migraine with Aura and Menstrual Migraine

    Directory of Open Access Journals (Sweden)

    Munvar Miya Shaik

    2015-01-01

    Full Text Available Migraine is the most common form of headache disorder globally. The etiology of migraine is multifactorial, with genetic components and environmental interactions considered to be the main causal factors. Some researchers postulate that deficits in mitochondrial energy reserves can cause migraine or an increase in homocysteine levels can lead to migraine attacks; therefore, vitamins could play a vital role in migraine prevention. For instance, riboflavin influences mitochondrial dysfunction and prevents migraine. Genes such as flavoenzyme 5,10-methylenetetrahydrofolate reductase (MTHFR, especially the C677T variant, have been associated with elevated plasma levels of homocysteine and migraine with aura. Homocysteine catalyzation requires the presence of vitamins B6, B12, and folic acid, which can decrease the severity of migraine with aura, making these vitamins potentially useful prophylactic agents for treating migraine with aura. Menstrual migraine, on the other hand, is associated with increased prostaglandin (PG levels in the endometrium, indicating a role for vitamin E, which is an anti-PG. Vitamin C can also be used as a scavenger of reactive oxygen species for treating neurogenic inflammation in migraine patients. This paper reviews possible therapies based on vitamin supplementation for migraine prophylaxis, focusing on migraine with aura and menstrual migraine.

  10. A reference GNSS tropospheric dataset over Europe.

    Science.gov (United States)

    Pacione, Rosa; Di Tomaso, Simona

    2016-04-01

    The present availability of 18 years of GNSS data belonging to the European Permanent Network (EPN, http://www.epncb.oma.be/) is a valuable database for the development of a climate data record of GNSS tropospheric products over Europe. This dataset has high potential for monitoring trend and variability in atmospheric water vapour, improving the knowledge of climatic trends of atmospheric water vapour and being useful for global and regional NWP reanalyses as well as climate model simulations. In the framework of the EPN-Repro2, a second reprocessing campaign of the EPN, five Analysis Centres have homogenously reprocessed the EPN network for the 1996-2013. Three Analysis Centres are providing homogenously reprocessed solutions for the entire network, which are analyzed by the three different software packages: Bernese, GAMIT and GIPSY-OASIS. Smaller subnetworks based on Bernese 5.2 are also provided. A huge effort is made for providing solutions that are the basis for deriving new coordinates, velocities and troposphere parameters, Zenith Tropospheric Delays and Horizontal Gradients, for the entire EPN. These individual contributions are combined in order to provide the official EPN reprocessed products. A preliminary tropospheric combined solution for the period 1996-2013 has been carried out. It is based on all the available homogenously reprocessed solutions and it offers the possibility to assess each of them prior to the ongoing final combination. We will present the results of the EPN Repro2 tropospheric combined products and how the climate community will benefit from them. Aknowledgment.The EPN Repro2 working group is acknowledged for providing the EPN solutions used in this work. E-GEOS activity is carried out in the framework of ASI contract 2015-050-R.0.

  11. Type of preoperative aura may predict postsurgical outcome in patients with temporal lobe epilepsy and mesial temporal sclerosis.

    Science.gov (United States)

    Asadi-Pooya, Ali A; Nei, Maromi; Sharan, Ashwini; Sperling, Michael R

    2015-09-01

    As the initial symptoms of epileptic seizures, many types of auras have significant localizing or lateralizing value. In this study, we hypothesized that the type of aura may predict postsurgical outcome in patients with medically refractory temporal lobe epilepsy (TLE) and mesial temporal sclerosis (MTS). In this retrospective study, all patients with a clinical diagnosis of medically refractory TLE due to unilateral mesial temporal sclerosis who underwent epilepsy surgery at the Jefferson Comprehensive Epilepsy Center were recruited. Patients were prospectively registered in a database from 1986 through 2014. Postsurgical outcome was classified into two groups: seizure freedom or relapse. Outcome was compared between seven groups of patients according to their preoperative auras. Two hundred thirty-seven patients were studied. The chance of becoming free of seizures after surgery in patients with abdominal aura was 65.1%, while in other patients, this was 43.3% (P=0.01). In two-by-two comparisons, no other significant differences were observed. Patients with medically refractory TLE-MTS who reported abdominal auras preceding their seizures fared better postoperatively with regard to seizure control compared with those who did not report auras, which may indicate bitemporal dysfunction, and to patients with other auras, which may indicate a widespread epileptogenic zone in the latter group of patients. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Evaluation of water vapour assimilation in the tropical upper troposphere and lower stratosphere by a chemical transport model

    Science.gov (United States)

    Payra, Swagata; Ricaud, Philippe; Abida, Rachid; El Amraoui, Laaziz; Attié, Jean-Luc; Rivière, Emmanuel; Carminati, Fabien; von Clarmann, Thomas

    2016-09-01

    The present analysis deals with one of the most debated aspects of the studies on the upper troposphere/lower stratosphere (UTLS), namely the budget of water vapour (H2O) at the tropical tropopause. Within the French project "Multiscale water budget in the upper troposphere and lower stratosphere in the TROpics" (TRO-pico), a global-scale analysis has been set up based on space-borne observations, models and assimilation techniques. The MOCAGE-VALENTINA assimilation tool has been used to assimilate the Aura Microwave Limb Sounder (MLS) version 3.3 H2O measurements within the 316-5 hPa range from August 2011 to March 2013 with an assimilation window of 1 h. Diagnostics based on observations minus analysis and forecast are developed to assess the quality of the assimilated H2O fields. Comparison with an independent source of H2O measurements in the UTLS based on the space-borne Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) observations and with meteorological ARPEGE analyses is also shown. Sensitivity studies of the analysed fields have been performed by (1) considering periods when no MLS measurements are available and (2) using H2O data from another MLS version (4.2). The studies have been performed within three different spaces in time and space coincidences with MLS (hereafter referred to as MLS space) and MIPAS (MIPAS space) observations and with the model (model space) outputs and at three different levels: 121 hPa (upper troposphere), 100 hPa (tropopause) and 68 hPa (lower stratosphere) in January and February 2012. In the MLS space, the analyses behave consistently with the MLS observations from the upper troposphere to the lower stratosphere. In the model space, the analyses are wetter than the reference atmosphere as represented by ARPEGE and MLS in the upper troposphere (121 hPa) and around the tropopause (100 hPa), but are consistent with MLS and MIPAS in the lower stratosphere (68 hPa). In the MIPAS space, the sensitivity and the

  13. Avaliação da utilização do placebo nas crises agudas de migrânea sem aura, migrânea com aura e cefaléia do tipo tensional episódica Evaluation of placebo use in migraine without aura, migraine with aura and episodic tension-type headache acute attacks

    Directory of Open Access Journals (Sweden)

    Marcelo Eduardo Bigal

    2001-09-01

    Full Text Available O presente estudo apresenta a avaliação do efeito placebo no tratamento agudo da migrânea sem aura, migrânea com aura e cefaléia do tipo tensional episódica. Foram estudados pacientes que deram entrada entre 1 de março de 1997 a 31 de novembro de 1999 em dois pronto-socorros. Definiram-se três grupos, cada um com 30 pacientes: 1 - migrânea sem aura (MSA; 2 -- migrânea com aura (MCO; 3 -- cefaléia do tipo tensional episódica (CTTE. Os pacientes participavam de estudo randomizado para avaliar a eficácia de 4 drogas; aqueles randomizados para o placebo foram incluídos também. Os parâmetros avaliados foram: 1 -- dor; 2 - sintomas associados. Avaliados uma hora após a administração do placebo, 50% dos pacientes do grupo MSA, 23,3% dos pacientes do grupo MCA e 26,7% dos pacientes do grupo CTTE apresentavam melhora da dor. A melhora, avaliada pela escala numérica da dor foi, em média, de 41,6%, 23,1% e 36%, respectivamente. Houve também redução significativa de todos os sintomas associados. A utilização do placebo é, portanto, essencial na avaliação de drogas utilizadas no tratamento de cefaléias agudas.This study presents an evaluation of placebo response in the acute treatment of migraine with or without aura and episodic tension type headache. We studied patients admitted between March 1st,1997 and November 31st,1999 in two Emergency Room Units. Three groups had been defined, each one with 30 participants: migraine without aura (MWOA, migraine with aura (MWA and episodic tension-type headache (ETTH. Patients were participating of a randomized study to evaluate efficacy of 4 different drugs; those randomized to receive placebo were included. We evaluated pain and associated symptoms. After one hour of placebo administration, 50% of MWOA patients, 23.3% of MWA and 26.7% of ETTH had presented pain relief. The mean of this relief, evaluated by the numerical pain scale, was 41.6%, 23.1% and 36%, respectively. Use of placebo

  14. Role of convection in determining the budget of odd hydrogen in the upper troposphere

    Science.gov (United States)

    Collins, W. J.; Stevenson, D. S.; Johnson, C. E.; Derwent, R. G.

    1999-11-01

    This paper presents a model study of the changes in upper tropospheric HOx ( = OH + HO2) due to upward convective transport of surface pollutants. The model used is a three-dimensional global Lagrangian tropospheric chemistry transport model of 70 chemical species and 150 reactions including nonmethane hydrocarbon chemistry. It is driven by meteorological data from the U.K. Meterological Office with a 6 hour time resolution. We find that the effect of convection is to increase upper tropospheric (300-200 hPa) HOx globally by over 50%. The effect is greatest over the tropical continents where convection and VOC emissions from vegetation are colocated. The convection of isoprene, and hydroperoxides has the greatest effect. Convecting formaldehyde and acetone has a lesser effect. The contribution from isoprene depends more on the convection of its degradation products than the convection of isoprene itself. The upper tropospheric HOx budget is shown to be very sensitive to the model implementation of convective wet deposition.

  15. Tropospheric Bromine Chemistry: Implications for Present and Pre-industrial Ozone and Mercury

    Science.gov (United States)

    Parella, J. P.; Jacob, D. J.; Liang, Q.; Zhang, Y.; Mickley, L. J.; Miller, B.; Evans, M. J.; Yang, X.; Pyle, J. A.; Theys, N.; hide

    2012-01-01

    We present a new model for the global tropospheric chemistry of inorganic bromine (Bry) coupled to oxidant-aerosol chemistry in the GEOS-Chem chemical transport model (CTM). Sources of tropospheric Bry include debromination of sea-salt aerosol, photolysis and oxidation of short-lived bromocarbons, and transport from the stratosphere. Comparison to a GOME-2 satellite climatology of tropospheric BrO columns shows that the model can reproduce the observed increase of BrO with latitude, the northern mid-latitudes maximum in winter, and the Arctic maximum in spring. This successful simulation is contingent on the HOBr + HBr reaction taking place in aqueous aerosols and ice clouds. Bromine chemistry in the model decreases tropospheric ozone mixing ratios by mercury against oxidation by Br. This suggests that historical anthropogenic mercury emissions may have mostly deposited to northern mid-latitudes, enriching the corresponding surface reservoirs. The persistent rise in background surface ozone at northern mid-latitudes during the past decades could possibly contribute to the observations of elevated mercury in subsurface waters of the North Atlantic.

  16. La "visión del aura" como experiencia alucinatoria en individuos no-clinicos The aura experience as cognitive perceptual schizotypy in non-clinical population

    Directory of Open Access Journals (Sweden)

    Alejandro Parra

    2008-12-01

    Full Text Available Individuos que dicen ver el aura/energía en forma espontánea también tienden a tener un nivel más elevado de actividad imaginativa/fantaseosa o de propensidad a la fantasía. Hay indicadores que muestran que quienes experimentan alta capacidad de absorción, usualmente experimentan también diversas formas parasomáticas, alucinaciones táctiles, y sensaciones de energías sutiles, asi como también ideación esquizotípica, error perceptual, y mayor sinestesia. El objetivo es correlacionar puntajes de absorción psicológica, disociación, propensidad a la fantasía, intensidad de la imaginería, y tendencia a la esquizotipia en individuos que dicen ver el aura (N=83 en comparación con un grupo sin experiencias (N=503. La muestra incluyó 678 estudiantes de psicología de ambos sexos, 449 (76,5% mujeres y 139 (23,5% varones, cuya rango etario es de 17 y 57 años (Media=25,54; SD=7,22 residentes en la Ciudad de Buenos Aires y alrededores. Ningun estudiante recibió compensación económica. Respecto a la experiencia de ver el aura, se formuló la pregunta de la siguiente manera: "¿Ha tenido alguna experiencia usted es capaz de ver campos de energia o luces alrededor del cuerpo de una persona? (si duda, por favor, responda no". Si la respuesta es afirmativa, la pregunta también mapea tres dimensiones de la experiencia: frecuencia de la experiencia, explicación subjetiva (racional, desconocida y paranormal de la experiencia, y positivo o negativo impacto (emocional en una escala Likert, siendo 1 positivo y 7 negativo. Los resultados muestran mayor nivel de esquizotipia cognitivo perceptual en comparación con quienes no tienen la experiencia. Posiblemente, estas personas tienen mucha más intensa vida imaginativa. Esta experiencia no necesariamente posee un significado psicopatológico para el individuo; quienes ven el aura simplemente podrían ser sensibles a las experiencias perceptuales anómalas.Individuals who claim being able to

  17. Comparative Analysis of Seasonal Variation in Tropospheric Nitrogen Dioxide over Pakistan and Saudi Arabia

    Science.gov (United States)

    Fahim Khokhar, Muhammad; Wagner, Thomas; Jamil, Mohsin

    2016-07-01

    In this study, spatial and temporal distributions of tropospheric NO2 vertical column densities over Pakistan and Saudi Arabia during the time period of 2004-2015 are discussed. Data products from the satellite instrument OMI are used. The results show a large NO2 growth over major cities of both countries, particularly the areas with rapid urbanization. Different seasonal cycles were observed over both countries. Especially, seasonal variation in tropospheric NO2 over Pakistan is largely impacted by the photolysis rate, OH radical and monsoon rains in addition to soil emissions, agriculture fires and other anthropogenic activities. While in the case of Saudi Arabia, the seasonal variation in tropospheric NO2 is completely driven by thermal power generation. Furthermore, different regions of Pakistan exhibited different seasonal trends. In the provinces of Punjab (north-east), Khyber Paktunkhwa (north-west) and Sindh (south-east), NO2 columns are maximum in winter and minimum in summer months while a reversed seasonality was observed in the province of Baluchistan (south-west). We compared the observed Spatio-temporal patterns to existing emission inventories and found that for the most populated provinces the NOx emissions are clearly dominated by anthropogenic sources. In these areas also the strongest positive trends were observed. NOx released from soils and produced by lightning both together contribute about 20% for the provinces of Punjab, Sindh, and Khyber Pakhtunkhwa, while its contribution in Baluchistan is much stronger (~50%). NOx emissions from biomass burning are negligible. This finding can also explain the observed summer maximum in Baluchistan since the highest lightning activity occurs during the Monsoon season. Our comparison also indicates that the inventories of anthropogenic NOx emissions over Pakistan seem to underestimate the true emissions by about a factor of two.

  18. Aura-biomes are present in the water layer above coral reef benthic macro-organisms

    Directory of Open Access Journals (Sweden)

    Kevin Walsh

    2017-08-01

    Full Text Available As coral reef habitats decline worldwide, some reefs are transitioning from coral- to algal-dominated benthos with the exact cause for this shift remaining elusive. Increases in the abundance of microbes in the water column has been correlated with an increase in coral disease and reduction in coral cover. Here we investigated how multiple reef organisms influence microbial communities in the surrounding water column. Our study consisted of a field assessment of microbial communities above replicate patches dominated by a single macro-organism. Metagenomes were constructed from 20 L of water above distinct macro-organisms, including (1 the coral Mussismilia braziliensis, (2 fleshy macroalgae (Stypopodium, Dictota and Canistrocarpus, (3 turf algae, and (4 the zoanthid Palythoa caribaeorum and were compared to the water microbes collected 3 m above the reef. Microbial genera and functional potential were annotated using MG-RAST and showed that the dominant benthic macro-organisms influence the taxa and functions of microbes in the water column surrounding them, developing a specific “aura-biome”. The coral aura-biome reflected the open water column, and was associated with Synechococcus and functions suggesting oligotrophic growth, while the fleshy macroalgae aura-biome was associated with Ruegeria, Pseudomonas, and microbial functions suggesting low oxygen conditions. The turf algae aura-biome was associated with Vibrio, Flavobacterium, and functions suggesting pathogenic activity, while zoanthids were associated with Alteromonas and functions suggesting a stressful environment. Because each benthic organism has a distinct aura-biome, a change in benthic cover will change the microbial community of the water, which may lead to either the stimulation or suppression of the recruitment of benthic organisms.

  19. Aura-biomes are present in the water layer above coral reef benthic macro-organisms.

    Science.gov (United States)

    Walsh, Kevin; Haggerty, J Matthew; Doane, Michael P; Hansen, John J; Morris, Megan M; Moreira, Ana Paula B; de Oliveira, Louisi; Leomil, Luciana; Garcia, Gizele D; Thompson, Fabiano; Dinsdale, Elizabeth A

    2017-01-01

    As coral reef habitats decline worldwide, some reefs are transitioning from coral- to algal-dominated benthos with the exact cause for this shift remaining elusive. Increases in the abundance of microbes in the water column has been correlated with an increase in coral disease and reduction in coral cover. Here we investigated how multiple reef organisms influence microbial communities in the surrounding water column. Our study consisted of a field assessment of microbial communities above replicate patches dominated by a single macro-organism. Metagenomes were constructed from 20 L of water above distinct macro-organisms, including (1) the coral Mussismilia braziliensis, (2) fleshy macroalgae (Stypopodium, Dictota and Canistrocarpus), (3) turf algae, and (4) the zoanthid Palythoa caribaeorum and were compared to the water microbes collected 3 m above the reef. Microbial genera and functional potential were annotated using MG-RAST and showed that the dominant benthic macro-organisms influence the taxa and functions of microbes in the water column surrounding them, developing a specific "aura-biome". The coral aura-biome reflected the open water column, and was associated with Synechococcus and functions suggesting oligotrophic growth, while the fleshy macroalgae aura-biome was associated with Ruegeria, Pseudomonas, and microbial functions suggesting low oxygen conditions. The turf algae aura-biome was associated with Vibrio, Flavobacterium, and functions suggesting pathogenic activity, while zoanthids were associated with Alteromonas and functions suggesting a stressful environment. Because each benthic organism has a distinct aura-biome, a change in benthic cover will change the microbial community of the water, which may lead to either the stimulation or suppression of the recruitment of benthic organisms.

  20. Self-concept evaluation and migraine without aura in childhood

    Directory of Open Access Journals (Sweden)

    Esposito M

    2013-08-01

    Full Text Available Maria Esposito,1 Beatrice Gallai,2 Lucia Parisi,3 Laura Castaldo,1 Rosa Marotta,4 Serena Marianna Lavano,4 Giovanni Mazzotta,5 Michele Roccella,3 Marco Carotenuto11Center for Childhood Headache, Clinic of Child and Adolescent Neuropsychiatry, Department of Mental Health, Physical and Preventive Medicine, Second University of Naples, Naples, Italy; 2Unit of Child and Adolescent Neuropsychiatry, University of Perugia, Perugia, Italy; 3Child Neuropsychiatry, Department of Psychology, University of Palermo, Palermo, Italy; 4Department of Psychiatry, "Magna Graecia" University of Catanzaro, Catanzaro, Italy; 5Unit of Child and Adolescent Neuropsychiatry, AUSL Umbria 2, Terni, ItalyIntroduction: Self-esteem is related to the broadly understood concept of self-schemas and is a crucial mechanism for a correct psychological development in children and adolescents. The impact of the many psychological difficulties linked to the migraine without aura (MoA and recurrent headache attacks, such as anger and separation anxiety, on self-esteem has not yet been well investigated. The aims of the present study were to assess self-esteem levels in an objective way and to verify their possible relationship and correlation with the frequency and intensity of migraine attacks, in a population of children and adolescents affected by MoA.Methods: The study population was comprised of 185 children (88 males [M], 97 females [F] aged between 6 and 12 years (mean 9.04 ± 2.41 years referred consecutively for MoA to the Center for Childhood Headache, Clinic of Child and Adolescent Neuropsychiatry, Second University of Naples and of 203 healthy controls (95 M, 108 F with mean age 9.16 ± 2.37 years, recruited from schools in Campania. The monthly headache frequency and the mean headache duration were assessed from daily headache diaries kept by all the children, and MoA intensity was assessed on a VAS (visual analog scale. To further evaluate their level of self-concept, all

  1. Upper-tropospheric CO and O3 budget during the Asian summer monsoon

    Science.gov (United States)

    Barret, Brice; Sauvage, Bastien; Bennouna, Yasmine; Le Flochmoen, Eric

    2016-07-01

    During the Asian summer monsoon, the circulation in the upper troposphere/lower stratosphere (UTLS) is dominated by the Asian monsoon anticyclone (AMA). Pollutants convectively uplifted to the upper troposphere are trapped within this anticyclonic circulation that extends from the Pacific Ocean to the Eastern Mediterranean basin. Among the uplifted pollutants are ozone (O3) and its precursors, such as carbon monoxide (CO) and nitrogen oxides (NOx). Many studies based on global modeling and satellite data have documented the source regions and transport pathways of primary pollutants (CO, HCN) into the AMA. Here, we aim to quantify the O3 budget by taking into consideration anthropogenic and natural sources. We first use CO and O3 data from the MetOp-A/IASI sensor to document their tropospheric distributions over Asia, taking advantage of the useful information they provide on the vertical dimension. These satellite data are used together with MOZAIC tropospheric profiles recorded in India to validate the distributions simulated by the global GEOS-Chem chemistry transport model. Over the Asian region, UTLS monthly CO and O3 distributions from IASI and GEOS-Chem display the same large-scale features. UTLS CO columns from GEOS-Chem are in agreement with IASI, with a low bias of 11 ± 9 % and a correlation coefficient of 0.70. For O3, the model underestimates IASI UTLS columns over Asia by 14 ± 26 % but the correlation between both is high (0.94). GEOS-Chem is further used to quantify the CO and O3 budget through sensitivity simulations. For CO, these simulations confirm that South Asian anthropogenic emissions have a more important impact on enhanced concentrations within the AMA (˜ 25 ppbv) than East Asian emissions (˜ 10 ppbv). The correlation between enhanced emissions over the Indo-Gangetic Plain and monsoon deep convection is responsible for this larger impact. Consistently, South Asian anthropogenic NOx emissions also play a larger role in producing O3 within

  2. Consistent High-Quality Global SO2 and HCHO Datasets from EOS Aura/OMI and Suomi NPP/OMPS

    Science.gov (United States)

    Li, C.; Joiner, J.; Krotkov, N. A.; Fioletov, V.; McLinden, C. A.; Zhang, Y.

    2015-12-01

    We report on recent effort and progress at NASA Goddard Space Flight Center in developing consistent SO2 and HCHO retrieval products from Aura/Ozone Monitoring Instrument (OMI) and Suomi National Polar-orbiting Partnership (S-NPP)/Ozone Mapping and Profiler Suite (OMPS) nadir mapper. Given the substantial differences between OMI and OMPS in several key aspects, such as spatial and spectral resolution and signal-to-noise ratio, a major challenge in ensuring data continuity between the two instruments is to properly account for different instrument characteristics as well as instruments' degradation over time. To this end, we have developed an innovative approach based on principal component analysis (PCA) of measured Earthshine radiances. We utilize a PCA technique to extract a series of spectral features (principal components or PCs) explaining the variance of measured reflectance spectra, associated with both physical processes (e.g., ozone absorption, rotational Raman scattering) and measurement details (e.g., wavelength shift). By fitting these PCs along with pre-computed Jacobians for our target species (SO2 or HCHO) to the measured radiance spectra, we can estimate the atmospheric loading of SO2 or HCHO while minimizing the impacts of interfering processes and measurement imperfection on retrievals. Since no explicit instrument-specific radiance data correction scheme is required, the PCA method is easily implemented with both OMI and OMPS and maximizes data continuity. The PCA algorithm currently runs operationally in the production of the new generation NASA standard OMI planetary boundary layer (PBL) SO2 data that have been shown to improve the detection limit of anthropogenic SO2 emission sources by a factor of two, as compared with the previous generation product. In this presentation, we will demonstrate that the PCA algorithm can produce SO2 and HCHO retrievals from OMPS that have comparable data quality with our OMI retrievals. We will also demonstrate

  3. OMI, TROPOMI, TROPOLITE: towards 1 x 1 km2 Air Quality and Emission monitoring

    Science.gov (United States)

    Levelt, Pieternel; Veefkind, Pepijn; Apituley, Arnoud; Vlemmix, Tim; Court, Andy; de Goeij, Bryan

    2017-04-01

    The Ozone Monitoring Instrument (OMI), launched on board of NASA's EOS-Aura spacecraft on July 15, 2004, provides unique contributions to air quality monitoring from Space. The combination of urban scale resolution (13 x 24 km2 in nadir) and daily global coverage proved to be key features for the air quality community. The OMI data is currently used operationally for improving the air quality forecasts, for inverting high-resolution emission maps, UV forecast and volcanic plume warning systems for aviation. Due to its 12 year decade long continuous operation OMI provides the longest NO2 and SO2 record from space, which is essential to understand the changes to emissions globally. In 2017 Tropospheric Monitoring Instrument (TROPOMI), will be launched on board ESA's Sentinel 5 Precursor satellite. TROPOMI will have a spatial resolution of 7x7 km2 in nadir; a more than 6 times improvement over OMI. The high spatial resolution serves two goals: (1) emissions sources can be detected with even better accuracy and (2) the number of cloud-free ground pixels will increase substantially. TROPOMI will continue OMI's ozone and air quality trace gas records. Added to that TROPOMI will measure the O2 A band for better cloud detection, as well as CO and the second most important greenhouse gas CH4. TROPOMI will therefore be an important satellite mission for the EU Copernicus atmosphere service and will be followed by ESA's sentinel 4 and 5 satellites. In the coming decades air pollution in megacities will continue to be a major area of concern and the need for timely, high resolution information on emissions will increase, preferably to a level where sources can be isolated on the level. TROPOLITE can be viewed as an add-on to the Copernicus suite of atmospheric satellite instruments, adding high-resolution potential to the Copernicus backbone. An overview of air quality applications, emission inventories, and trend analyses will be given, based on the excellent OMI data record

  4. The changing face of lower tropospheric sulfur oxides in the United States

    Directory of Open Access Journals (Sweden)

    G. M. Hidy

    2016-12-01

    Full Text Available Abstract Sulfur oxides, sulfur dioxide and airborne sulfate, SOx, are short-lived species in the troposphere whose concentrations in air and precipitation have changed dramatically in association with fossil fuel combustion. The historic rise in concentration is coincident with the era of the so-called “Anthropocene.” Unlike concentrations of long-lived species such as carbon dioxide, atmospheric SOx in the United States (US peaked between 1970 and 2005 then declined. The rise and fall of SOx is traced by comparing national data on emission changes, ambient concentrations, and precipitation sulfate from prior to World War II to the present. Surface SOx concentrations and precipitation sulfate have decreased with emissions in most parts of the US after the late 1970s. Continued reduction toward a natural “background” condition has depended on aggressive management of anthropogenic emission sources. Annual average ambient concentrations of SO2 and SO4 have become more uniform across the US at levels of 1–3 ppbv and 0.3–3 µg/m3, respectively. Precipitation SO4 has a nominal concentration generally less than 0.5 mg/L. The effective lifetime of SOx in the troposphere is a few days. This duration limits the spatial extent of emission source influence of SOx to regional scales, wherein spatial gradients in species concentrations lead to variations in human exposure and impacts on vulnerable terrestrial and aquatic ecosystems. The effects of domestic emission reductions on SOx levels are moderated by intra- and intercontinental transport of SOx from Canada, Mexico, Asia and elsewhere. The trends in tropospheric SOx concentrations illustrate the results of more than a century of rising public awareness and action to progressively reduce a US environmental risk, accomplished with advances in energy production technology that have maintained economic well-being.

  5. Tropospheric ozone and its regional transport over Cape Town

    Science.gov (United States)

    Nzotungicimpaye, Claude-Michel; Abiodun, Babatunde J.; Steyn, Douw G.

    2014-04-01

    As part of efforts to understand the sources of air pollution in Cape Town, this study investigates the local variation of tropospheric ozone (O3) and identifies possible advection paths of O3 pollution from a remote source to Cape Town. Measurements of O3 and wind from three sites in the Cape Town area were analyzed to study the local variations of O3. At each site, the diurnal variation of O3 is found to be mainly driven by photochemical production while the seasonal variation of O3 is mostly driven by wind conditions. The highest concentration of O3 is observed at the remote site (Cape Point) while lowest O3 concentration is observed at the sub-urban site (Goodwood), where there are chemical sinks of O3 such as NOx. Atmospheric pollution over southern Africa was simulated to study the regional transport of O3. The simulations show that extreme O3 levels in Cape Town can be caused by air pollution transported from the industrial Highveld of South Africa, in the lower troposphere. Such extreme O3 pollution events over Cape Town are simulated to occur in January (14%), March (44%), April (28%) and September (14%). Lagrangian trajectories suggest four paths by which air parcels can be transported from the industrial Highveld to Cape Town: a north-easterly path which is the most frequent route, a tropical deviation route, a deviation along the south coastline and an oceanic deviation path which is the less frequent route. The major advection paths associated with poor air quality in Cape Town are the north-easterly route and the path along the south coastline of the country. Hence the study suggests that emissions in the industrial Highveld may contribute to O3 concentration in the Cape Town area.

  6. The global distribution of tropospheric NO{sub x} estimated by a 3-D chemical tracer model

    Energy Technology Data Exchange (ETDEWEB)

    Kraus, A.B.; Rohrer, F.; Ehhalt, D.H. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Atmosphaerische Chemie

    1997-12-31

    The global distribution of NO{sub x} in the troposphere is calculated using a three-dimensional chemical tracer model with a simplified chemistry scheme for the tracers NO{sub x} {identical_to} NO +