Updated SO2 emission estimates over China using OMI/Aura observations

Directory of Open Access Journals (Sweden)

M. E. Koukouli

2018-03-01

Full Text Available The main aim of this paper is to update existing sulfur dioxide (SO2 emission inventories over China using modern inversion techniques, state-of-the-art chemistry transport modelling (CTM and satellite observations of SO2. Within the framework of the EU Seventh Framework Programme (FP7 MarcoPolo (Monitoring and Assessment of Regional air quality in China using space Observations project, a new SO2 emission inventory over China was calculated using the CHIMERE v2013b CTM simulations, 10 years of Ozone Monitoring Instrument (OMI/Aura total SO2 columns and the pre-existing Multi-resolution Emission Inventory for China (MEIC v1.2. It is shown that including satellite observations in the calculations increases the current bottom-up MEIC inventory emissions for the entire domain studied (15–55° N, 102–132° E from 26.30 to 32.60 Tg annum−1, with positive updates which are stronger in winter ( ∼  36 % increase. New source areas were identified in the southwest (25–35° N, 100–110° E as well as in the northeast (40–50° N, 120–130° E of the domain studied as high SO2 levels were observed by OMI, resulting in increased emissions in the a posteriori inventory that do not appear in the original MEIC v1.2 dataset. Comparisons with the independent Emissions Database for Global Atmospheric Research, EDGAR v4.3.1, show a satisfying agreement since the EDGAR 2010 bottom-up database provides 33.30 Tg annum−1 of SO2 emissions. When studying the entire OMI/Aura time period (2005 to 2015, it was shown that the SO2 emissions remain nearly constant before the year 2010, with a drift of −0.51 ± 0.38 Tg annum−1, and show a statistically significant decline after the year 2010 of −1.64 ± 0.37 Tg annum−1 for the entire domain. Similar findings were obtained when focusing on the greater Beijing area (30–40° N, 110–120° E with pre-2010 drifts of −0.17 ± 0.14 and post-2010

Implementation 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.

2014-12-01

The updated status of TEMPO, as it proceeds from formulation phase into implementation phase is presented. TEMPO, the first NASA 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 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. GEO-CAPE is not planned for implementation this decade. However, instruments from Europe (Sentinel 4) and Asia (GEMS) will form parts of a global GEO constellation for pollution monitoring later this decade, with a major focus on intercontinental

A New Retrieval Algorithm for OMI NO2: Tropospheric Results and Comparisons with Measurements and Models

Science.gov (United States)

Swartz, W. H.; Bucesla, E. J.; Lamsal, L. N.; Celarier, E. A.; Krotkov, N. A.; Bhartia, P, K,; Strahan, S. E.; Gleason, J. F.; Herman, J.; Pickering, K.

2012-01-01

Nitrogen oxides (NOx =NO+NO2) are important atmospheric trace constituents that impact tropospheric air pollution chemistry and air quality. We have developed a new NASA algorithm for the retrieval of stratospheric and tropospheric NO2 vertical column densities using measurements from the nadir-viewing Ozone Monitoring Instrument (OMI) on NASA's Aura satellite. The new products rely on an improved approach to stratospheric NO2 column estimation and stratosphere-troposphere separation and a new monthly NO2 climatology based on the NASA Global Modeling Initiative chemistry-transport model. The retrieval does not rely on daily model profiles, minimizing the influence of a priori information. We evaluate the retrieved tropospheric NO2 columns using surface in situ (e.g., AQS/EPA), ground-based (e.g., DOAS), and airborne measurements (e.g., DISCOVER-AQ). The new, improved OMI tropospheric NO2 product is available at high spatial resolution for the years 200S-present. We believe that this product is valuable for the evaluation of chemistry-transport models, examining the spatial and temporal patterns of NOx emissions, constraining top-down NOx inventories, and for the estimation of NOx lifetimes.

Uncertainty in biogenic isoprene emissions and its impacts on tropospheric chemistry in East Asia

International Nuclear Information System (INIS)

Han, K.M.; Park, R.S.; Kim, H.K.; Woo, J.H.; Kim, J.; Song, C.H.

2013-01-01

In this study, the accuracy of biogenic isoprene emission fluxes over East Asia during two summer months (July and August) was examined by comparing two tropospheric HCHO columns (Ω HCHO ) obtained from the SCIAMACHY sensor and the Community Multi-scale Air Quality (CMAQ v4.7.1) model simulations, using three available biogenic isoprene emission inventories over East Asia: i) GEIA, ii) MEGAN and iii) MOHYCAN. From this comparative analysis, the tropospheric HCHO columns from the CMAQ model simulations, using the MEGAN and MOHYCAN emission inventories (Ω CMAQ, MEGAN and Ω CMAQ, MOHYCAN ), were found to agree well with the tropospheric HCHO columns from the SCIAMACHY observations (Ω SCIA ). Secondly, the propagation of such uncertainties in the biogenic isoprene emission fluxes to the levels of atmospheric oxidants (e.g., OH and HO 2 ) and other atmospheric gaseous/particulate species over East Asia during the two summer months was also investigated. As the biogenic isoprene emission fluxes decreased from the GEIA to the MEGAN emission inventories, the levels of OH radicals increased by factors of 1.39 and 1.75 over Central East China (CEC) and South China, respectively. Such increases in the OH radical mixing ratios subsequently influence the partitioning of HO y species. For example, the HO 2 /OH ratios from the CMAQ model simulations with GEIA isoprene emissions were 2.7 times larger than those from the CMAQ model simulations based on MEGAN isoprene emissions. The large HO 2 /OH ratios from the CMAQ model simulations with the GEIA biogenic emission were possibly due to the overestimation of GEIA biogenic isoprene emissions over East Asia. It was also shown that such large changes in HO x radicals created large differences on other tropospheric compounds (e.g., NO y chemistry) over East Asia during the summer months. - Highlights: • GEIA isoprene emissions were possibly overestimated over East Asia. • Using MEGAN or MOHYCAN emissions in CMAQ well captured

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...... head pain, headache and aura symptoms were contralateral in 90% and ipsilateral in 10%....

Uncertainty in biogenic isoprene emissions and its impacts on tropospheric chemistry in East Asia

Energy Technology Data Exchange (ETDEWEB)

Han, K.M.; Park, R.S. [School of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 500-712 (Korea, Republic of); Advanced Environmental Monitoring Research Center (ADEMRC), Gwangju Institute of Science and Technology (GIST), Gwangju, 500-712 (Korea, Republic of); Kim, H.K.; Woo, J.H. [Department of Advanced Technology Fusion, Konkuk University, 1 Hwayang dong, Gwangjin-gu, Seoul, 143-701 (Korea, Republic of); Kim, J. [Department of Atmospheric Sciences, Yonsei University, 134 Sinchon-dong, Seodaemoon-gu, Seoul, 120-749 (Korea, Republic of); Song, C.H., E-mail: chsong@gist.ac.kr [School of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 500-712 (Korea, Republic of); Advanced Environmental Monitoring Research Center (ADEMRC), Gwangju Institute of Science and Technology (GIST), Gwangju, 500-712 (Korea, Republic of)

2013-10-01

In this study, the accuracy of biogenic isoprene emission fluxes over East Asia during two summer months (July and August) was examined by comparing two tropospheric HCHO columns (Ω{sub HCHO}) obtained from the SCIAMACHY sensor and the Community Multi-scale Air Quality (CMAQ v4.7.1) model simulations, using three available biogenic isoprene emission inventories over East Asia: i) GEIA, ii) MEGAN and iii) MOHYCAN. From this comparative analysis, the tropospheric HCHO columns from the CMAQ model simulations, using the MEGAN and MOHYCAN emission inventories (Ω{sub CMAQ,} {sub MEGAN} and Ω{sub CMAQ,} {sub MOHYCAN}), were found to agree well with the tropospheric HCHO columns from the SCIAMACHY observations (Ω{sub SCIA}). Secondly, the propagation of such uncertainties in the biogenic isoprene emission fluxes to the levels of atmospheric oxidants (e.g., OH and HO{sub 2}) and other atmospheric gaseous/particulate species over East Asia during the two summer months was also investigated. As the biogenic isoprene emission fluxes decreased from the GEIA to the MEGAN emission inventories, the levels of OH radicals increased by factors of 1.39 and 1.75 over Central East China (CEC) and South China, respectively. Such increases in the OH radical mixing ratios subsequently influence the partitioning of HO{sub y} species. For example, the HO{sub 2}/OH ratios from the CMAQ model simulations with GEIA isoprene emissions were 2.7 times larger than those from the CMAQ model simulations based on MEGAN isoprene emissions. The large HO{sub 2}/OH ratios from the CMAQ model simulations with the GEIA biogenic emission were possibly due to the overestimation of GEIA biogenic isoprene emissions over East Asia. It was also shown that such large changes in HO{sub x} radicals created large differences on other tropospheric compounds (e.g., NO{sub y} chemistry) over East Asia during the summer months. - Highlights: • GEIA isoprene emissions were possibly overestimated over East Asia. �

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...

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

Science.gov (United States)

Luo, M.; Boxe, C.; Jiang, J.; Nassar, R.; Livesey, N.

2009-11-01

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 currently not

Uncertainty in biogenic isoprene emissions and its impacts on tropospheric chemistry in East Asia.

Science.gov (United States)

Han, K M; Park, R S; Kim, H K; Woo, J H; Kim, J; Song, C H

2013-10-01

In this study, the accuracy of biogenic isoprene emission fluxes over East Asia during two summer months (July and August) was examined by comparing two tropospheric HCHO columns (ΩHCHO) obtained from the SCIAMACHY sensor and the Community Multi-scale Air Quality (CMAQ v4.7.1) model simulations, using three available biogenic isoprene emission inventories over East Asia: i) GEIA, ii) MEGAN and iii) MOHYCAN. From this comparative analysis, the tropospheric HCHO columns from the CMAQ model simulations, using the MEGAN and MOHYCAN emission inventories (Ω(CMAQ, MEGAN) and Ω(CMAQ, MOHYCAN)), were found to agree well with the tropospheric HCHO columns from the SCIAMACHY observations (Ω(SCIA)). Secondly, the propagation of such uncertainties in the biogenic isoprene emission fluxes to the levels of atmospheric oxidants (e.g., OH and HO2) and other atmospheric gaseous/particulate species over East Asia during the two summer months was also investigated. As the biogenic isoprene emission fluxes decreased from the GEIA to the MEGAN emission inventories, the levels of OH radicals increased by factors of 1.39 and 1.75 over Central East China (CEC) and South China, respectively. Such increases in the OH radical mixing ratios subsequently influence the partitioning of HO(y) species. For example, the HO2/OH ratios from the CMAQ model simulations with GEIA isoprene emissions were 2.7 times larger than those from the CMAQ model simulations based on MEGAN isoprene emissions. The large HO2/OH ratios from the CMAQ model simulations with the GEIA biogenic emission were possibly due to the overestimation of GEIA biogenic isoprene emissions over East Asia. It was also shown that such large changes in HO(x) radicals created large differences on other tropospheric compounds (e.g., NO(y) chemistry) over East Asia during the summer months. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

Impact of biogenic terpene emissions from Brassica napus on tropospheric ozone over Saxony (Germany): numerical investigation.

Science.gov (United States)

Renner, Eberhard; Münzenberg, Annette

2003-01-01

The role of biogenic emissions in tropospheric ozone production is currently under discussion and major aspects are not well understood yet. This study aims towards the estimation of the influence of biogenic emissions on tropospheric ozone concentrations over Saxony in general and of biogenic emissions from brassica napus in special. MODELLING TOOLS: The studies are performed by utilizing a coupled numerical modelling system consisting of the meteorological model METRAS and the chemistry transport model MUSCAT. For the chemical part, the Euro-RADM algorithm is used. EMISSIONS: Anthropogenic and biogenic emissions are taken into account. The anthropogenic emissions are introduced by an emission inventory. Biogenic emissions, VOC and NO, are calculated within the chemical transport model MUSCAT at each time step and in each grid cell depending on land use type and on the temperature. The emissions of hydrocarbons from forest areas as well as biogenic NO especially from agricultural grounds are considered. Also terpene emissions from brassica napus fields are estimated. SIMULATION SETUP AND METEOROLOGICAL CONDITIONS: The simulations were performed over an area with an extension of 160 x 140 km2 which covers the main parts of Saxony and neighboring areas of Brandenburg, Sachsen-Anhalt and Thuringia. Summer smog with high ozone concentrations can be expected during high pressure conditions on hot summer days. Typical meteorological conditions for such cases were introduced in an conceptual way. It is estimated that biogenic emissions change tropospheric ozone concentrations in a noticeable way (up to 15% to 20%) and, therefore, should not be neglected in studies about tropospheric ozone. Emissions from brassica napus do have a moderate potential to enhance tropospheric ozone concentrations, but emissions are still under consideration and, therefore, results vary to a high degree. Summing up, the effect of brassica napus terpene emissions on ozone concentrations is

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.;

Migraine aura

DEFF Research Database (Denmark)

Charles, Andrew; Hansen, Jakob Møller

2015-01-01

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....... SUMMARY: There has been significant evolution of concepts regarding the causes of migraine aura, how it is best defined, and how it fits into the picture of the migraine disorder as a whole. Regardless of its exact role in the genesis of migraine, an increased understanding of aura has the potential...

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

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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.

Source attribution of tropospheric ozone

Science.gov (United States)

Butler, T. M.

2015-12-01

Tropospheric ozone is a harmful pollutant with adverse effects on human health and ecosystems. As well as these effects, tropospheric ozone is also a powerful greenhouse gas, with an anthropogenic radiative forcing one quarter of that of CO2. Along with methane and atmospheric aerosol, tropospheric ozone belongs to the so-called Short Lived Climate forcing Pollutants, or SLCP. Recent work has shown that efforts to reduce concentrations of SLCP in the atmosphere have the potential to slow the rate of near-term climate change, while simultaneously improving public health and reducing crop losses. Unlike many other SLCP, tropospehric ozone is not directly emitted, but is instead influenced by two distinct sources: transport of air from the ozone-rich stratosphere; and photochemical production in the troposphere from the emitted precursors NOx (oxides of nitrogen), CO (Carbon Monoxide), and VOC (volatile organic compounds, including methane). Better understanding of the relationship between ozone production and the emissions of its precursors is essential for the development of targeted emission reduction strategies. Several modeling methods have been employed to relate the production of tropospheric ozone to emissions of its precursors; emissions perturbation, tagging, and adjoint sensitivity methods all deliver complementary information about modelled ozone production. Most studies using tagging methods have focused on attribution of tropospheric ozone production to emissions of NOx, even though perturbation methods have suggested that tropospheric ozone is also sensitive to VOC, particularly methane. In this study we describe the implementation into a global chemistry-climate model of a scheme for tagging emissions of NOx and VOC with an arbitrary number of labels, which are followed through the chemical reactions of tropospheric ozone production in order to perform attribution of tropospehric ozone to its emitted precursors. Attribution is performed to both

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

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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.

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

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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

Top-down NOX Emissions of European Cities Derived from Modelled and Spaceborne Tropospheric NO2 Columns

Science.gov (United States)

Verstraeten, W. W.; Boersma, K. F.; Douros, J.; Williams, J. E.; Eskes, H.; Delcloo, A. W.

2017-12-01

High nitrogen oxides (NOX = NO + NO2) concentrations near the surface impact humans and ecosystems badly and play a key role in tropospheric chemistry. NO2 is an important precursor of tropospheric ozone (O3) which in turn affects the production of the hydroxyl radical controlling the chemical lifetime of key atmospheric pollutants and reactive greenhouse gases. Combustion from industrial, traffic and household activities in large and densely populated urban areas result in high NOX emissions. Accurate mapping of these emissions is essential but hard to do since reported emissions factors may differ from real-time emissions in order of magnitude. Modelled NO2 levels and lifetimes also have large associated uncertainties and overestimation in the chemical lifetime which may mask missing NOX chemistry in current chemistry transport models (CTM's). The simultaneously estimation of both the NO2 lifetime and as well as the concentrations by applying the Exponentially Modified Gaussian (EMG) method on tropospheric NO2 columns lines densities should improve the surface NOX emission estimates. Here we evaluate if the EMG methodology applied on the tropospheric NO2 columns simulated by the LOTOS-EUROS (Long Term Ozone Simulation-European Ozone Simulation) CTM can reproduce the NOX emissions used as model input. First we process both the modelled tropospheric NO2 columns for the period April-September 2013 for 21 selected European urban areas under windy conditions (averaged vertical wind speeds between surface and 500 m from ECMWF > 2 m s-1) as well as the accompanying OMI (Ozone Monitoring Instrument) data providing us with real-time observation-based estimates of midday NO2 columns. Then we compare the top-down derived surface NOX emissions with the 2011 MACC-III emission inventory, used in the CTM as input to simulate the NO2 columns. For cities where NOX emissions can be assumed as originating from one large source good agreement is found between the top-down derived

OMI/Aura Nitrogen Dioxide (NO2) Total and Tropospheric Column 1-orbit L2 Swath 13x24 km V003

Data.gov (United States)

National Aeronautics and Space Administration — The second release of collection 3 OMI/Aura Level-2 NO2 data product OMNO2 is now available (http://disc.gsfc.nasa.gov/Aura/OMI/omno2_v003.shtml ) to public and...

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

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

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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

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

OpenAIRE

M. Parrington; P. I. Palmer; D. K. Henze; D. W. Tarasick; E. J. Hyer; R. C. Owen; D. Helmig; C. Clerbaux; K. W. Bowman; M. N. Deeter; E. M. Barratt; P.-F. Coheur; D. Hurtmans; M. George; J. R. Worden

2011-01-01

We analyse 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. In comparison to observations from the PICO-NARE observatory in the Azores, ozonesondes across Canada, and the Tropospheric Emission Spectrometer (TES) and Infrared Atmospheric Sounding Instrument (IASI) satellite instr...

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.

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

Science.gov (United States)

Parrington, M.; Palmer, P. I.; Henze, D. K.; Tarasick, D. W.; Hyer, E. J.; Owen, R. C.; Helmig, D.; Clerbaux, C.; Bowman, K. W.; Deeter, M. N.; Barratt, E. M.; Coheur, P.-F.; Hurtmans, D.; Jiang, Z.; George, M.; Worden, J. R.

2012-02-01

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, reducing the mean model bias from 5.5 to 4.0 ppbv

Ozone Depletion in Tropospheric Volcanic Plumes: From Halogen-Poor to Halogen-Rich Emissions

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Tjarda J. Roberts

2018-02-01

Full Text Available Volcanic halogen emissions to the troposphere undergo a rapid plume chemistry that destroys ozone. Quantifying the impact of volcanic halogens on tropospheric ozone is challenging, only a few observations exist. This study presents measurements of ozone in volcanic plumes from Kīlauea (HI, USA, a low halogen emitter. The results are combined with published data from high halogen emitters (Mt Etna, Italy; Mt Redoubt, AK, USA to identify controls on plume processes. Ozone was measured during periods of relatively sustained Kīlauea plume exposure, using an Aeroqual instrument deployed alongside Multi-Gas SO2 and H2S sensors. Interferences were accounted for in data post-processing. The volcanic H2S/SO2 molar ratio was quantified as 0.03. At Halema‘uma‘u crater-rim, ozone was close to ambient in the emission plume (at 10 ppmv SO2. Measurements in grounding plume (at 5 ppmv SO2 about 10 km downwind of Pu‘u ‘Ō‘ō showed just slight ozone depletion. These Kīlauea observations contrast with substantial ozone depletion reported at Mt Etna and Mt Redoubt. Analysis of the combined data from these three volcanoes identifies the emitted Br/S as a strong but non-linear control on the rate of ozone depletion. Model simulations of the volcanic plume chemistry highlight that the proportion of HBr converted into reactive bromine is a key control on the efficiency of ozone depletion. This underlines the importance of chemistry in the very near-source plume on the fate and atmospheric impacts of volcanic emissions to the troposphere.

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

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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.

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

Directory of Open Access Journals (Sweden)

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 NO_x 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 NO_x 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

Analysis of the summertime buildup of tropospheric ozone abundances over the Middle East and North Africa as observed by the Tropospheric Emission Spectrometer instrument

Science.gov (United States)

Liu, Jane J.; Jones, Dylan B. A.; Worden, John R.; Noone, David; Parrington, Mark; Kar, Jay

2009-03-01

We use the GEOS-Chem chemical transport model to interpret observations of tropospheric ozone from the Tropospheric Emission Spectrometer (TES) satellite instrument in summer 2005. Observations from TES reveal elevated ozone in the middle troposphere (500-400 hPa) across North Africa and the Middle East. Observed ozone abundances in the middle troposphere are at a maximum in summer and a minimum in winter, consistent with the previously predicted summertime "Middle East ozone maximum." This summertime enhancement in ozone is associated with the Arabian and Sahara anticyclones, centered over the Zagros and Atlas Mountains, respectively. These anticyclones isolate the middle troposphere over northeast Africa and the Middle East, with westerlies to the north and easterlies to the south, facilitating the buildup of ozone. Over the Middle East, we find that in situ production and transport from Asia provides comparable contributions of 30-35% to the ozone buildup. Over North Africa, in situ production is dominant (at about 20%), with transport from Asia, North America, and equatorial Africa each contributing about 10-15% to the total ozone. We find that although the eastern Mediterranean is characterized by strong descent in the middle and upper troposphere in summer, transport from the boundary layer accounts for about 25% of the local Middle Eastern contribution to the ozone enhancement in the middle troposphere. This upward transport of boundary layer air is associated with orographic lifting along the Zagros Mountains in Iran and the Asir and Hijaz Mountain ranges in Saudi Arabia, and is consistent with TES observations of deuterated water.

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;

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.

Evaluating climate model performance in the tropics with retrievals of water isotopic composition from Aura TES

Science.gov (United States)

Field, Robert; Kim, Daehyun; Kelley, Max; LeGrande, Allegra; Worden, John; Schmidt, Gavin

2014-05-01

Observational and theoretical arguments suggest that satellite retrievals of the stable isotope composition of water vapor could be useful for climate model evaluation. The isotopic composition of water vapor is controlled by the same processes that control water vapor amount, but the observed distribution of isotopic composition is distinct from amount itself . This is due to the fractionation that occurs between the abundant H216O isotopes (isotopologues) and the rare and heavy H218O and HDO isotopes during evaporation and condensation. The fractionation physics are much simpler than the underlying moist physics; discrepancies between observed and modeled isotopic fields are more likely due to problems in the latter. Isotopic measurements therefore have the potential for identifying problems that might not be apparent from more conventional measurements. Isotopic tracers have existed in climate models since the 1980s but it is only since the mid 2000s that there have been enough data for meaningful model evaluation in this sense, in the troposphere at least. We have evaluated the NASA GISS ModelE2 general circulation model over the tropics against water isotope (HDO/H2O) retrievals from the Aura Tropospheric Emission Spectrometer (TES), alongside more conventional measurements. A small ensemble of experiments was performed with physics perturbations to the cumulus and planetary boundary layer schemes, done in the context of the normal model development process. We examined the degree to which model-data agreement could be used to constrain a select group of internal processes in the model, namely condensate evaporation, entrainment strength, and moist convective air mass flux. All are difficult to parameterize, but exert strong influence over model performance. We found that the water isotope composition was significantly more sensitive to physics changes than precipitation, temperature or relative humidity through the depth of the tropical troposphere. Among the

Exploding Head Syndrome as Aura of Migraine with Brainstem Aura: A Case Report.

Science.gov (United States)

Rossi, Fabian H; Gonzalez, Elizabeth; Rossi, Elisa Marie; Tsakadze, Nina

2018-01-01

This article reports a case of exploding head syndrome (EHS) as an aura of migraine with brainstem aura (MBA). A middle-aged man presented with intermittent episodes of a brief sensation of explosion in the head, visual flashing, vertigo, hearing loss, tinnitus, confusion, ataxia, dysarthria, and bilateral visual impairment followed by migraine headache. The condition was diagnosed as MBA. Explosive head sensation, sensory phenomena, and headaches improved over time with nortriptyline. This case shows that EHS can present as a primary aura symptom in patients with MBA.

The Impact of Uncertainties in African Biomass Burning Emission Estimates on Modeling Global Air Quality, Long Range Transport and Tropospheric Chemical Lifetimes

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Guido R. van der Werf

2012-02-01

Full Text Available The chemical composition of the troposphere in the tropics and Southern Hemisphere (SH is significantly influenced by gaseous emissions released from African biomass burning (BB. Here we investigate how various emission estimates given in bottom-up BB inventories (GFEDv2, GFEDv3, AMMABB affect simulations of global tropospheric composition using the TM4 chemistry transport model. The application of various model parameterizations for introducing such emissions is also investigated. There are perturbations in near-surface ozone (O3 and carbon monoxide (CO of ~60–90% in the tropics and ~5–10% in the SH between different inventories. Increasing the update frequency of the temporal distribution to eight days generally results in decreases of between ~5 and 10% in near-surface mixing ratios throughout the tropics, which is larger than the influence of increasing the injection heights at which BB emissions are introduced. There are also associated differences in the long range transport of pollutants throughout the SH, where the composition of the free troposphere in the SH is sensitive to the chosen BB inventory. Analysis of the chemical budget terms reveals that the influence of increasing the tropospheric CO burden due to BB on oxidative capacity of the troposphere is mitigated by the associated increase in NOx emissions (and thus O3 with the variations in the CO/N ratio between inventories being low. For all inventories there is a decrease in the tropospheric chemical lifetime of methane of between 0.4 and 0.8% regardless of the CO emitted from African BB. This has implications for assessing the effect of inter-annual variability in BB on the annual growth rate of methane.

Impact of climate variability on tropospheric ozone

International Nuclear Information System (INIS)

Grewe, Volker

2007-01-01

A simulation with the climate-chemistry model (CCM) E39/C is presented, which covers both the troposphere and stratosphere dynamics and chemistry during the period 1960 to 1999. Although the CCM, by its nature, is not exactly representing observed day-by-day meteorology, there is an overall model's tendency to correctly reproduce the variability pattern due to an inclusion of realistic external forcings, like observed sea surface temperatures (e.g. El Nino), major volcanic eruption, solar cycle, concentrations of greenhouse gases, and Quasi-Biennial Oscillation. Additionally, climate-chemistry interactions are included, like the impact of ozone, methane, and other species on radiation and dynamics, and the impact of dynamics on emissions (lightning). However, a number of important feedbacks are not yet included (e.g. feedbacks related to biogenic emissions and emissions due to biomass burning). The results show a good representation of the evolution of the stratospheric ozone layer, including the ozone hole, which plays an important role for the simulation of natural variability of tropospheric ozone. Anthropogenic NO x emissions are included with a step-wise linear trend for each sector, but no interannual variability is included. The application of a number of diagnostics (e.g. marked ozone tracers) allows the separation of the impact of various processes/emissions on tropospheric ozone and shows that the simulated Northern Hemisphere tropospheric ozone budget is not only dominated by nitrogen oxide emissions and other ozone pre-cursors, but also by changes of the stratospheric ozone budget and its flux into the troposphere, which tends to reduce the simulated positive trend in tropospheric ozone due to emissions from industry and traffic during the late 80s and early 90s. For tropical regions the variability in ozone is dominated by variability in lightning (related to ENSO) and stratosphere-troposphere exchange (related to Northern Hemisphere Stratospheric

Satellite Observations of Tropospheric BrO over Salt Lakes and Northern High Latitudes from EOS/OMI and SNPP/OMPS

Science.gov (United States)

Kurosu, T. P.; Stutz, J.; Brockway, N.; Saiz-Lopez, A.; Suleiman, R. M.; Natraj, V.; Jaross, G.; Seftor, C. J.

2017-12-01

We present observations of tropospheric bromine monoxide (BrO) derived from two satellite instruments: the Ozone Monitoring Instrument (OMI) on EOS-Aura, and the Nadir Mapper component of the Ozone Mapping and Profiler Suite (OMPS) on Suomi/NPP. BrO observations from OMPS constitute a new and experimental measurement that we first report on here and compare with the standard BrO data product from OMI. BrO is a halogen oxide present mostly in the lower stratosphere, where it catalytically destroys ozone with about 25 times the efficiency of ClO. BrO also has a tropospheric component, where it is released from sea surfaces, at the interface of ocean water and sea ice in the polar spring, in volcanic plumes, and in the vicinity of salt lakes. Tropospheric BrO has been linked to mercury (Hg) deposition through BrO-induced conversion of gaseous Hg to reactive Hg, which is then deposited on the surface and enters the food chain, ultimately affecting human health. As part of NASA's Aura Science Team, we are developing an OMI Tropospheric BrO data product that provides a unique global data set on BrO spatial and vertical distribution in the troposphere and stratosphere. Information of this kind is currently unavailable from any of the past and present bromine-monitoring instruments. In this presentation, we focus on multi-year time series of BrO released from a range of salt lakes - the Rann of Kutch, Salar de Uyuni, the Aral Sea, and others. We quantify the amount of bromine released from the lakes and investigate the possibility of lake desiccation monitoring based on independent BrO observations. The quality and limits of OMI and OMPS tropospheric BrO observations is investigated by comparison with ground-based MAX-DOAS observations over central Greenland.

Obisdian sourcing by PIXE analysis at AURA2

International Nuclear Information System (INIS)

Neve, S.R.; Barker, P.H.; Holroyd, S.; Sheppard, P.J.

1994-01-01

The technique of Proton Induced X-ray Emission is a suitable method for the elemental analysis of obsidian samples and artefacts. By comparing the elemental composition of obsidian artefacts with those of known sources of obsidian and identifying similarities, the likely origin of the sample can be discovered and information about resource procurement gained. A PIXE facility has now been established at the Auckland University Research Accelerator Laboratory, AURA2. It offers a rapid, multi-element, non-destructive method of characterisation of obsidian samples ranging from small chips to large pieces. In an extensive survey of Mayor Island obsidian, a discrimination has been made between the different locations of obsidian deposits on the island. In addition, using the database developed at AURA2, artefacts from the site of Opita, Hauraki Plains, have been sourced. (Author). 18 refs., 8 figs., 7 tabs., 1 appendix

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,...

Effects of anthropogenic emissions on tropospheric ozone and its radiative forcing

Energy Technology Data Exchange (ETDEWEB)

Berntsen, T.; Isaksen, I.S.A.; Fuglestvedt, J.S.; Myhre, G.; Larsen, T. Alsvik; Stordal, F.; Freckleton, R.S.; Shine, K.P.

1997-12-31

As described in this report, changes in tropospheric ozone since pre-industrial times due to changes in emissions have been calculated by the University of Oslo global three-dimensional photochemical model. The radiative forcing caused by the increase in ozone has been calculated by means of two independent radiative transfer models: the University of Reading model (Reading), and the University of Oslo/Norwegian Institute for Air Research model (OsloRad). Significant increases in upper tropospheric ozone concentrations are found at northern mid-latitudes at about 10 km altitude. In the tropical regions the largest increase is found at about 15 km altitude. The increase is found to be caused mainly by enhanced in situ production due to transport of precursors from the boundary layer, with a smaller contribution from increased transport of ozone produced in the boundary layer. The lifetime of ozone in the troposphere decreased by about 35% as a result of enhanced concentrations of HO{sub 2}. The calculated increase in surface ozone in Europe is in good agreement with observations. The calculations of radiative forcing include the effect of clouds and allow for thermal adjustment in the stratosphere. The global and annual averaged radiative forcing at the tropopause from both models are in the lower part of the Intergovernmental Panel on Climate Change estimated range. The calculated radiative forcing is similar in magnitude to the negative radiative forcing by sulfate aerosols, but displaced southward in source regions at northern mid-latitudes. The increase in tropospheric ozone is calculated to have cooled the lower stratosphere by up to 0.9 K, with possibly half of this cooling occurring in the past 2 to 3 decades. 76 refs., 16 figs., 9 tabs.

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.

SO2 over Central China: Measurements, Numerical Simulations and the Tropospheric Sulfur Budget

Science.gov (United States)

He, Hao; Li, Can; Loughner, Christopher P.; Li, Zhangqing; Krotkov, Nickolay A.; Yang, Kai; Wang, Lei; Zheng, Youfei; Bao, Xiangdong; Zhao, Guoqiang;

OMI/Aura NO2 Total and Tropospheric Column Daily L2 Global 0.25 deg Lat/Lon Grid V003

Data.gov (United States)

National Aeronautics and Space Administration — The second Release of Collection 003 of OMI/Aura Global Gridded Nitrogen Dioxide Product 'OMNO2G' is now available, from the NASA Goddard Earth Sciences Data and...

Impacts of biogenic emissions of VOC and NOx on tropospheric ozone during summertime in eastern China.

Science.gov (United States)

Wang, Qin'geng; Han, Zhiwei; Wang, Tijian; Zhang, Renjian

2008-05-20

This study is intended to understand and quantify the impacts of biogenic emissions of volatile organic compounds (VOC) and nitrogen oxides (NO(x)) on the formation of tropospheric ozone during summertime in eastern China. The model system consists of the non-hydrostatic mesoscale meteorological model (MM5) and a tropospheric chemical and transport model (TCTM) with the updated carbon-bond chemical reaction mechanism (CBM-IV). The spatial resolution of the system domain is 30 km x 30 km. The impacts of biogenic emissions are investigated by performing simulations (36 h) with and without biogenic emissions, while anthropogenic emissions are constant. The results indicate that biogenic emissions have remarkable impacts on surface ozone in eastern China. In big cities and their surrounding areas, surface ozone formation tends to be VOC-limited. The increase in ozone concentration by biogenic VOC is generally 5 ppbv or less, but could be more than 10 ppbv or even 30 ppbv in some local places. The impacts of biogenic NO(x) are different or even contrary in different regions, depending on the relative availability of NO(x) and VOC. The surface ozone concentrations reduced or increased by the biogenic NO(x) could be as much as 10 ppbv or 20 ppbv, respectively. The impacts of biogenic emissions on ozone aloft are generally restricted to the boundary layer and generally more obvious during the daytime than during the nighttime. This study is useful for understanding the role of biogenic emissions and for planning strategies for surface ozone abatement in eastern China. Due to limitations of the emission inventories used and the highly non-linear nature of zone formation, however, some uncertainties remain in the results.

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.;

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...

Revisiting the contribution of land transport and shipping emissions to tropospheric ozone

Science.gov (United States)

Mertens, Mariano; Grewe, Volker; Rieger, Vanessa S.; Jöckel, Patrick

2018-04-01

We quantify the contribution of land transport and shipping emissions to tropospheric ozone for the first time with a chemistry-climate model including an advanced tagging method (also known as source apportionment), which considers not only the emissions of nitrogen oxides (NOx, NO, and NO2), carbon monoxide (CO), and volatile organic compounds (VOC) separately, but also their non-linear interaction in producing ozone. For summer conditions a contribution of land transport emissions to ground-level ozone of up to 18 % in North America and Southern Europe is estimated, which corresponds to 12 and 10 nmol mol-1, respectively. The simulation results indicate a contribution of shipping emissions to ground-level ozone during summer on the order of up to 30 % in the North Pacific Ocean (up to 12 nmol mol-1) and 20 % in the North Atlantic Ocean (12 nmol mol-1). With respect to the contribution to the tropospheric ozone burden, we quantified values of 8 and 6 % for land transport and shipping emissions, respectively. Overall, the emissions from land transport contribute around 20 % to the net ozone production near the source regions, while shipping emissions contribute up to 52 % to the net ozone production in the North Pacific Ocean. To put these estimates in the context of literature values, we review previous studies. Most of them used the perturbation approach, in which the results for two simulations, one with all emissions and one with changed emissions for the source of interest, are compared. For a better comparability with these studies, we also performed additional perturbation simulations, which allow for a consistent comparison of results using the perturbation and the tagging approach. The comparison shows that the results strongly depend on the chosen methodology (tagging or perturbation approach) and on the strength of the perturbation. A more in-depth analysis for the land transport emissions reveals that the two approaches give different results

Estimates of the changes in tropospheric chemistry which result from human activity and their dependence on NO(x) emissions and model resolution

Science.gov (United States)

Kanakidou, Maria; Crutzen, Paul J.; Zimmermann, Peter H.

1994-01-01

As a consequence of the non-linear behavior of the chemistry of the atmosphere and because of the short lifetime of nitrogen oxides (NO(x)), two-dimensional models do not give an adequate description of the production and destruction rates of NO(x) and their effects on the distributions of the concentration of ozone and hydroxyl radical. In this study, we use a three-dimensional model to evaluate the contribution of increasing NO(x) emissions from industrial activity and biomass burning to changes in the chemical composition of the troposphere. By comparing results obtained from longitudinally-uniform and longitudinally-varying emissions of NO(x), we demonstrate that the geographical representation of the NO(x) emissions is crucial in simulating tropospheric chemistry.

Modeling the impact of chlorine emissions from coal combustion and prescribed waste incineration on tropospheric ozone formation in China

Science.gov (United States)

Liu, Yiming; Fan, Qi; Chen, Xiaoyang; Zhao, Jun; Ling, Zhenhao; Hong, Yingying; Li, Weibiao; Chen, Xunlai; Wang, Mingjie; Wei, Xiaolin

2018-02-01

Chlorine radicals can enhance atmospheric oxidation, which potentially increases tropospheric ozone concentration. However, few studies have been done to quantify the impact of chlorine emissions on ozone formation in China due to the lack of a chlorine emission inventory used in air quality models with sufficient resolution. In this study, the Anthropogenic Chlorine Emissions Inventory for China (ACEIC) was developed for the first time, including emissions of hydrogen chloride (HCl) and molecular chlorine (Cl2) from coal combustion and prescribed waste incineration (waste incineration plant). The HCl and Cl2 emissions from coal combustion in China in 2012 were estimated to be 232.9 and 9.4 Gg, respectively, while HCl emission from prescribed waste incineration was estimated to be 2.9 Gg. Spatially the highest emissions of HCl and Cl2 were found in the North China Plain, the Yangtze River Delta, and the Sichuan Basin. Air quality model simulations with the Community Multiscale Air Quality (CMAQ) modeling system were performed for November 2011, and the modeling results derived with and without chlorine emissions were compared. The magnitude of the simulated HCl, Cl2 and ClNO2 agreed reasonably with the observation when anthropogenic chlorine emissions were included in the model. The inclusion of the ACEIC increased the concentration of fine particulate Cl-, leading to enhanced heterogeneous reactions between Cl- and N2O5, which resulted in the higher production of ClNO2. Photolysis of ClNO2 and Cl2 in the morning and the reaction of HCl with OH in the afternoon produced chlorine radicals which accelerated tropospheric oxidation. When anthropogenic chlorine emissions were included in the model, the monthly mean concentrations of fine particulate Cl-, daily maximum 1 h ClNO2, and Cl radicals were estimated to increase by up to about 2.0 µg m-3, 773 pptv, and 1.5 × 103 molecule cm-3 in China, respectively. Meanwhile, the monthly mean daily maximum 8 h O3

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

DEFF Research Database (Denmark)

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

2017-01-01

, 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...

Origins of Tropospheric Ozone Interannual Variation (IAV) over Reunion: A Model Investigation

Science.gov (United States)

Liu, Junhua; Rodriguez, Jose M.; Thompson, Anne M.; Logan, Jennifer A.; Douglass, Anne R.; Olsen, Mark A.; Steenrod, Stephen D.; Posny, Francoise

2016-01-01

Observations from long-term ozonesonde measurements show robust variations and trends in the evolution of ozone in the middle and upper troposphere over Reunion Island (21.1 degrees South Latitude, 55.5 degrees East Longitude) in June-August. Here we examine possible causes of the observed ozone variation at Reunion Island using hindcast simulations by the stratosphere-troposphere Global Modeling Initiative chemical transport model for 1992-2014, driven by assimilated Modern-Era Retrospective Analysis for Research and Applications (MERRA) meteorological fields. Reunion Island is at the edge of the subtropical jet, a region of strong stratospheric-tropospheric exchange. Our analysis implies that the large interannual variation (IAV) of upper tropospheric ozone over Reunion is driven by the large IAV of the stratospheric influence. The IAV of the large-scale, quasi-horizontal wind patterns also contributes to the IAV of ozone in the upper troposphere. Comparison to a simulation with constant emissions indicates that increasing emissions do not lead to the maximum trend in the middle and upper troposphere over Reunion during austral winter implied by the sonde data. The effects of increasing emission over southern Africa are limited tothe lower troposphere near the surface in August-September.

Aura-like features and photophobia in sightless migraine patients

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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.

North American Tropospheric Ozone Profiles from IONS (INTEX Ozonesonde Network Study, 2004, 2006): Ozone Budgets, Polution Statistics, Satellite Retrievals

Science.gov (United States)

Dougherty, M.; Thompson, A. M.; Witte, J. C.; Miller, S. K.; Oltmans, S. J.; Cooper, O. R.; Tarasick, D. W.; Chatfield, R. B.; Taubman, B. F.; Joseph, E.; Baumgardner, D.; Merrill, J. T.; Morris, G. A.; Rappenglueck, B.; Lefer, B.; Forbes, G.; Newchurch, M. J.; Schmidlin, F. J.; Pierce, R. B.; Leblanc, T.; Dubey, M.; Minschwaner, K.

2007-12-01

During INTEX-B (both Milagro and IMPEX phases in Spring 2006) and during the summer TEXAQS- 2006/GOMACCS period, the INTEX Ozonesonde Network Study (IONS-06) coordinated ozonesonde launches over North America for Aura overpasses. IONS-06 supported aircraft operations and provided profiles for ozone budgets and pollution transport, satellite validation and evaluation of models. In contrast to IONS-04, IONS-06 had a greater range (all but one 2004 IONS site plus a dozen in California, New Mexico, Mexico City, Barbados and southwestern Canada), yielding more than 700 profiles. Tropospheric pollution statistics to guide Aura satellite retrievals and contrasts in UT-LS (upper tropospheric-lower stratospheric) ozone between 2004 and 2006 are presented. With IONS-04 dominated by low-pressure conditions over northeastern North America, UT ozone originated 25% from the stratosphere [Thompson et al., 2007a,b] with significant amounts from aged or relatively fresh pollution and lightning [Cooper et al., 2006; Morris et al., 2006]. Both IONS-04 and IONS-06 summer periods displayed a persistent UT ozone maximum [Cooper et al., 2007] over the south-central US. March 2006 IONS sondes over Mexico manifested persistent UT/LS gravity wave influence and more sporadic pollution. Regional and seasonal contrasts in IONS-06 ozone distributions are described. intexb/ions06.html

Headache as an Aura of Epilepsy: Video-EEG Monitoring Study.

Science.gov (United States)

Kim, Dong Wook; Sunwoo, Jun-Sang; Lee, Sang Kun

2016-04-01

Headache can be associated with epilepsy as a pre-ictal, ictal, or post-ictal phenomenon; however, studies of patients with headache as an epileptic aura are scarce. We performed the present study to investigate the incidence and characteristics of headache as an epileptic aura, via confirmation of electroencephalography (EEG) changes by video-EEG monitoring. Data of aura and clinical seizure episodes of 831 consecutive patients who undertook video-EEG monitoring were analyzed retrospectively. For patients who had headache as an aura, information on the detailed features of headache was acquired, including location, nature, duration, and the presence of accompanying symptoms. Video-recorded clinical seizures, EEG findings, and neuroimaging data were used to determine the ictal onset areas in the patients. Six out of 831 (0.7%) patients experienced headache as aura (age range, 25-52 years), all of whom had partial seizures. The incidence of pre-ictal headache was 6.3% (25/831), and post-ictal headache was 30.9% (257/831). In patients with headache as aura, five patients described headache as the most frequent aura, and headache was the second most frequent aura in one patient. The characteristics of headache were hemicrania epileptica in two patients, tension-type headache in another two patients, and migraine-like headache in the remaining two patients. No patient met the diagnostic criteria of ictal epileptic headache or migraine aura-triggered seizure. Our study showed that headache as an aura is uncommon in adult patients with epilepsy, and that headache can present as diverse features, including hemicrania epileptica, tension-type headache, and migraine-like headache. Further studies are necessary to characterize the features of headache as an epileptic aura in adult patients with epilepsy. © 2016 American Headache Society.

Modeling the impact of chlorine emissions from coal combustion and prescribed waste incineration on tropospheric ozone formation in China

Directory of Open Access Journals (Sweden)

Y. Liu

2018-02-01

Full Text Available Chlorine radicals can enhance atmospheric oxidation, which potentially increases tropospheric ozone concentration. However, few studies have been done to quantify the impact of chlorine emissions on ozone formation in China due to the lack of a chlorine emission inventory used in air quality models with sufficient resolution. In this study, the Anthropogenic Chlorine Emissions Inventory for China (ACEIC was developed for the first time, including emissions of hydrogen chloride (HCl and molecular chlorine (Cl2 from coal combustion and prescribed waste incineration (waste incineration plant. The HCl and Cl2 emissions from coal combustion in China in 2012 were estimated to be 232.9 and 9.4 Gg, respectively, while HCl emission from prescribed waste incineration was estimated to be 2.9 Gg. Spatially the highest emissions of HCl and Cl2 were found in the North China Plain, the Yangtze River Delta, and the Sichuan Basin. Air quality model simulations with the Community Multiscale Air Quality (CMAQ modeling system were performed for November 2011, and the modeling results derived with and without chlorine emissions were compared. The magnitude of the simulated HCl, Cl2 and ClNO2 agreed reasonably with the observation when anthropogenic chlorine emissions were included in the model. The inclusion of the ACEIC increased the concentration of fine particulate Cl−, leading to enhanced heterogeneous reactions between Cl− and N2O5, which resulted in the higher production of ClNO2. Photolysis of ClNO2 and Cl2 in the morning and the reaction of HCl with OH in the afternoon produced chlorine radicals which accelerated tropospheric oxidation. When anthropogenic chlorine emissions were included in the model, the monthly mean concentrations of fine particulate Cl−, daily maximum 1 h ClNO2, and Cl radicals were estimated to increase by up to about 2.0 µg m−3, 773 pptv, and 1.5  ×  103 molecule cm−3 in China, respectively. Meanwhile

OMI/Aura NO2 Cloud-Screened Total and Tropospheric Column Daily L3 Global 0.25deg Lat/Lon Grid V003

Data.gov (United States)

National Aeronautics and Space Administration — The OMI/Aura Level-3 Global Gridded(0.25x0.25 deg) Nitrogen Dioxide Product "OMNO2d" is now released (Jan 10, 2013) to the public from the NASA Goddard Earth...

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.

Time-dependent inversion estimates of global biomass-burning CO emissions using Measurement of Pollution in the Troposphere (MOPITT) measurements

NARCIS (Netherlands)

Arellano, A.F.; Kasibhatla, P.S.; Giglio, L.; van der Werf, G.R.; Randerson, J.T; Collatz, G.J.

2006-01-01

We present an inverse-modeling analysis of CO emissions using column CO retrievals from the Measurement of Pollution in the Troposphere (MOPITT) instrument and a global chemical transport model (GEOS-CHEM). We first focus on the information content of MOPITT CO column retrievals in terms of

Estimates of Free-tropospheric NO2 Abundance from the Aura Ozone Monitoring Instrument (OMI) Using Cloud Slicing Technique

Science.gov (United States)

Choi, S.; Joiner, J.; Krotkov, N. A.; Choi, Y.; Duncan, B. N.; Celarier, E. A.; Bucsela, E. J.; Vasilkov, A. P.; Strahan, S. E.; Veefkind, J. P.; Cohen, R. C.; Weinheimer, A. J.; Pickering, K. E.

2013-12-01

Total column measurements of NO2 from space-based sensors are of interest to the atmospheric chemistry and air quality communities; the relatively short lifetime of near-surface NO2 produces satellite-observed hot-spots near pollution sources including power plants and urban areas. However, estimates of NO2 concentrations in the free-troposphere, where lifetimes are longer and the radiative impact through ozone formation is larger, are severely lacking. Such information is critical to evaluate chemistry-climate and air quality models that are used for prediction of the evolution of tropospheric ozone and its impact of climate and air quality. Here, we retrieve free-tropospheric NO2 volume mixing ratio (VMR) using the cloud slicing technique. We use cloud optical centroid pressures (OCPs) as well as collocated above-cloud vertical NO2 columns (defined as the NO2 column from top of the atmosphere to the cloud OCP) from the Ozone Monitoring Instrument (OMI). The above-cloud NO2 vertical columns used in our study are retrieved independent of a priori NO2 profile information. In the cloud-slicing approach, the slope of the above-cloud NO2 column versus the cloud optical centroid pressure is proportional to the NO2 volume mixing ratio (VMR) for a given pressure (altitude) range. We retrieve NO2 volume mixing ratios and compare the obtained 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 good when proper data screening is applied. In addition, the OMI cloud slicing reports a high NO2 VMR where the aircraft reported lightning NOx during the Deep Convection Clouds and Chemistry (DC3) campaign in 2012. We also provide a global seasonal climatology of free-tropospheric NO2 VMR in cloudy conditions. Enhanced NO2 in free troposphere commonly appears near polluted urban locations where NO2 produced in the boundary layer may be transported vertically out of the

Characterization of wildfire NOx emissions using MODIS fire radiative power and OMI tropospheric NO2 columns

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R. C. Cohen

2011-06-01

Full Text Available We use observations of fire radiative power (FRP from the Moderate Resolution Imaging Spectroradiometer~(MODIS and tropospheric NO2 column measurements from the Ozone Monitoring Instrument (OMI to derive NO2 wildfire emission coefficients (g MJ−1 for three land types over California and Nevada. Retrieved emission coefficients were 0.279±0.077, 0.342±0.053, and 0.696±0.088 g MJ−1 NO2 for forest, grass and shrub fuels, respectively. These emission coefficients reproduce ratios of emissions with fuel type reported previously using independent methods. However, the magnitude of these coefficients is lower than prior estimates. While it is possible that a negative bias in the OMI NO2 retrieval over regions of active fire emissions is partly responsible, comparison with several other studies of fire emissions using satellite platforms indicates that current emission factors may overestimate the contributions of flaming combustion and underestimate the contributions of smoldering combustion to total fire emissions. Our results indicate that satellite data can provide an extensive characterization of the variability in fire NOx emissions; 67 % of the variability in emissions in this region can be accounted for using an FRP-based parameterization.

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 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-NO_x. 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 NO_x 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 NO_x levels: high

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.

Rapid increases in tropospheric ozone production and export from China

NARCIS (Netherlands)

Verstraeten, W.W.; Neu, J.L.; Williams, J.E.; Bowman, K.W.; Worden, J.R.; Boersma, K.F.

2015-01-01

Rapid population growth and industrialization have driven substantial increases in Asian ozone precursor emissions over the past decade1, with highly uncertain impacts on regional and global tropospheric ozone levels. According to ozonesonde measurements2, 3, tropospheric ozone concentrations at two

Remote sensed and in situ constraints on processes affecting tropical tropospheric ozone

Directory of Open Access Journals (Sweden)

B. Sauvage

2007-01-01

Full Text Available We use a global chemical transport model (GEOS-Chem to evaluate the consistency of satellite measurements of lightning flashes and ozone precursors with in situ measurements of tropical tropospheric ozone. The measurements are tropospheric O3, NO2, and HCHO columns from the GOME satellite instrument, lightning flashes from the OTD and LIS satellite instruments, profiles of O3, CO, and relative humidity from the MOZAIC aircraft program, and profiles of O3 from the SHADOZ ozonesonde network. We interpret these multiple data sources with our model to better understand what controls tropical tropospheric ozone. Tropical tropospheric ozone is mainly affected by lightning NOx and convection in the upper troposphere and by surface emissions in the lower troposphere. Scaling the spatial distribution of lightning in the model to the observed flashes improves the simulation of O3 in the upper troposphere by 5–20 ppbv versus in situ observations and by 1–4 Dobson Units versus GOME retrievals of tropospheric O3 columns. A lightning source strength of 6±2 Tg N/yr best represents in situ observations from aircraft and ozonesonde. Tropospheric NO2 and HCHO columns from GOME are applied to provide top-down constraints on emission inventories of NOx (biomass burning and soils and VOCs (biomass burning. The top-down biomass burning inventory is larger than the bottom-up inventory by a factor of 2 for HCHO and alkenes, and by a factor of 2.6 for NOx over northern equatorial Africa. These emissions increase lower tropospheric O3 by 5–20 ppbv, improving the simulation versus aircraft observations, and by 4 Dobson Units versus GOME observations of tropospheric O3 columns. Emission factors in the a posteriori inventory are more consistent with a recent compilation from in situ measurements. The ozone simulation using two different dynamical schemes (GEOS-3 and GEOS-4 is evaluated versus observations; GEOS-4 better represents O3 observations by 5–15 ppbv

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...

Observing Tropospheric Ozone From Space

Science.gov (United States)

Fishman, Jack

2000-01-01

The importance of tropospheric ozone embraces a spectrum of relevant scientific issues ranging from local environmental concerns, such as damage to the biosphere and human health, to those that impact global change questions, Such is climate warming. From an observational perspective, the challenge is to determine the tropospheric ozone global distribution. Because its lifetime is short compared with other important greenhouse gases that have been monitored over the past several decades, the distribution of tropospheric ozone cannot be inferred from a relatively small set of monitoring stations. Therefore, the best way to obtain a true global picture is from the use of space-based instrumentation where important spatial gradients over vast ocean expanses and other uninhabited areas can be properly characterized. In this paper, the development of the capability to measure tropospheric ozone from space over the past 15 years is summarized. Research in the late 1980s successfully led to the determination of the climatology of tropospheric ozone as a function of season; more recently, the methodology has improved to the extent where regional air pollution episodes can be characterized. The most recent modifications now provide quasi-global (50 N) to 50 S) maps on a daily basis. Such a data set would allow for the study of long-range (intercontinental) transport of air pollution and the quantification of how regional emissions feed into the global tropospheric ozone budget. Future measurement capabilities within this decade promise to offer the ability to provide Concurrent maps of the precursors to the in situ formation of tropospheric ozone from which the scientific community will gain unprecedented insight into the processes that control global tropospheric chemistry

Highly resolved global distribution of tropospheric NO2 using GOME narrow swath mode data

Directory of Open Access Journals (Sweden)

S. Beirle

2004-01-01

Full Text Available The Global Ozone Monitoring Experiment (GOME allows the retrieval of tropospheric vertical column densities (VCDs of NO2 on a global scale. Regions with enhanced industrial activity can clearly be detected, but the standard spatial resolution of the GOME ground pixels (320x40km2 is insufficient to resolve regional trace gas distributions or individual cities. Every 10 days within the nominal GOME operation, measurements are executed in the so called narrow swath mode with a much better spatial resolution (80x40km2. We use this data (1997-2001 to construct a detailed picture of the mean global tropospheric NO2 distribution. Since - due to the narrow swath - the global coverage of the high resolution observations is rather poor, it has proved to be essential to deseasonalize the single narrow swath mode observations to retrieve adequate mean maps. This is done by using the GOME backscan information. The retrieved high resolution map illustrates the shortcomings of the standard size GOME pixels and reveals an unprecedented wealth of details in the global distribution of tropospheric NO2. Localised spots of enhanced NO2 VCD can be directly associated to cities, heavy industry centers and even large power plants. Thus our result helps to check emission inventories. The small spatial extent of NO2 'hot spots' allows us to estimate an upper limit of the mean lifetime of boundary layer NOx of 17h on a global scale. The long time series of GOME data allows a quantitative comparison of the narrow swath mode data to the nominal resolution. Thus we can analyse the dependency of NO2 VCDs on pixel size. This is important for comparing GOME data to results of new satellite instruments like SCIAMACHY (launched March 2002 on ENVISAT, OMI (launched July 2004 on AURA or GOME II (to be launched 2005 with an improved spatial resolution.

Observations of volcanic SO2 from MLS on Aura

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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.

Trigger factors in migraine with aura

DEFF Research Database (Denmark)

Hauge, A W; Kirchmann, M; Olesen, J

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...

Sublingual piroxicam in migraine without aura.

Science.gov (United States)

Ravishankar, K; Tayade, Himanshu; Mandlik, Rahul

2011-08-01

The aim of the present study was to compare the analgesic efficacy of a single dose of sublingual piroxicam to that of a placebo during acute attacks of migraine without aura. The drug (N = 30) or a placebo (N = 30) was administered, on randomisation and double-blind basis, to 60 patients between 18 and 50 years of age suffering from migraine without aura. The patients were instructed to take a single tablet sublingually [corresponding to piroxicam 40 mg or placebo] and the severity of the painful symptomatology and associated symptoms were evaluated by this study. The patients treated with sublingual piroxicam showed a significant (P piroxicam administration. In 83.3%, the drug resulted in excellent to good response as compared to only 10% in the placebo group. No local and systemic side effects were reported with sublingual piroxicam. The present study has demonstrated that for the acute management of migraine without aura sublingual piroxicam showed significant analgesic effect with excellent tolerability.

Multi-year composite view of ozone enhancements and stratosphere-to-troposphere transport in dry intrusions of northern hemisphere extratropical cyclones

Science.gov (United States)

Jaegle, L.; Wood, R.; Wargan, K.

2017-12-01

We examine the role of extratropical cyclones in stratosphere-to-troposphere (STT) exchange by using cyclone-centric composites of O3 retrievals from the Microwave Limb Sounder (MLS) and the Tropospheric Emission Spectrometer (TES) onboard the Aura satellite and contrasting them to composites obtained with Modern-Era Retrospective-analysis for Research and Applications (MERRA and MERRA-2) as well as with the GEOS-Chem chemical transport model. MERRA sea level pressure fields are used to identify 15,978 extratropical cyclones in the northern hemisphere (NH) between 2005 and 2012. The lowermost stratosphere (261 hPa) and middle troposphere (424 hPa) composites of these cyclones feature a distinct 1,000 km wide O3 enhancement in the dry intrusion to the southwest of the cyclone center, coinciding with a lowered tropopause, enhanced potential vorticity, and decreased water vapor. In the lowermost stratosphere, MLS composites show that the dry intrusion O3 enhancements reach a 210 ppbv maximum in April. In the middle troposphere, TES composites display dry intrusion maximum O3 enhancements of 27 ppbv in May. The magnitude and seasonality of these enhancements are captured by MERRA and MERRA-2, but GEOS-Chem is a factor of two too low. The MERRA-2 composites show that the O3-rich dry intrusion forms a coherent and vertically aligned structure between 300 and 800 hPa, wrapping cyclonically with the warm conveyor belt. In winter and spring dry intrusions, O3 is enhanced by 100 pbbv or 100-130% relative to background conditions at 300 hPa, with a significant contribution reaching pressure altitudes below 500 hPa (6-20 ppbv or 15-30% enhancement). We calculate that extratropical cyclones result in a STT flux of 119 Tg O3 yr-1, accounting for 42% of the annual NH O3 extratropical STT flux. The STT flux in cyclones is highest in spring and displays a strong dependence on westerly 300 hPa wind speeds.

Laser Safety and Hazard Analysis for the Trailer (B70) Based AURA Laser System

International Nuclear Information System (INIS)

AUGUSTONI, ARNOLD L.

2003-01-01

A laser safety and hazard analysis was performed for the AURA laser system based on the 2000 version of the American National Standards Institute's (ANSI) Standard Z136.1, for ''Safe Use of Lasers'' and the 2000 version of the ANSI Standard Z136.6, for ''Safe Use of Lasers Outdoors''. The trailer based AURA laser system is a mobile platform, which is used to perform laser interaction experiments and tests at various national test sites. The trailer (B70) based AURA laser system is generally operated on the United State Air Force Starfire Optical Range (SOR) at Kirtland Air Force Base (KAFB), New Mexico. The laser is used to perform laser interaction testing inside the laser trailer as well as outside the trailer at target sites located at various distances from the exit telescope. In order to protect personnel, who work inside the Nominal Hazard Zone (NHZ), from hazardous laser emission exposures it was necessary to determine the Maximum Permissible Exposure (MPE) for each laser wavelength (wavelength bands) and calculate the appropriate minimum Optical Density (OD min ) of the laser safety eyewear used by authorized personnel and the Nominal Ocular Hazard Distance (NOHD) to protect unauthorized personnel who may have violated the boundaries of the control area and enter into the laser's NHZ

HR Mission | AURA Human Resources

Science.gov (United States)

AURA Policies Conflict of Interest Employee Recognition Forms Library Handbook Integrity Line Manager responsiveness; Striving for a multicultural, innovative and diverse team that operates with respect and

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

= 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...... is underestimated, especially in children and those with learning disabilities....

Impact of nonlinearity on changing the a priori of trace gas profile estimates from the Tropospheric Emission Spectrometer (TES

Directory of Open Access Journals (Sweden)

S. S. Kulawik

2008-06-01

Full Text Available Non-linear maximum a posteriori (MAP estimates of atmospheric profiles from the Tropospheric Emission Spectrometer (TES contains a priori information that may vary geographically, which is a confounding factor in the analysis and physical interpretation of an ensemble of profiles. One mitigation strategy is to transform profile estimates to a common prior using a linear operation thereby facilitating the interpretation of profile variability. However, this operation is dependent on the assumption of not worse than moderate non-linearity near the solution of the non-linear estimate. The robustness of this assumption is tested by comparing atmospheric retrievals from the Tropospheric Emission Spectrometer processed with a uniform prior with those processed with a variable prior and converted to a uniform prior following the non-linear retrieval. Linearly converting the prior following a non-linear retrieval is shown to have a minor effect on the results as compared to a non-linear retrieval using a uniform prior when compared to the expected total error, with less than 10% of the change in the prior ending up as unbiased fluctuations in the profile estimate results.

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

Science.gov (United States)

Revell, L. E.; Tummon, F.; Stenke, A.; Sukhodolov, T.; Coulon, A.; Rozanov, E.; Garny, H.; Grewe, V.; Peter, T.

2015-05-01

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 (including methane effects) and stratospheric ozone recovery on the tropospheric ozone budget, in a simulation following the climate scenario Representative Concentration Pathway (RCP) 6.0 (a medium-high, and reasonably realistic climate scenario). Changes in ozone precursor emissions have the largest effect, leading to a global-mean increase in tropospheric ozone which maximizes in the early 21st century at 23% compared to 1960. 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 long lifetime 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 by the end of the 21st century, with an 11 % increase at northern midlatitudes. This increase maximizes in the 2080s and is mostly caused by methane, which maximizes in the 2080s following RCP 6.0, and plays an important role in controlling ozone directly, and indirectly through its

Abnormal functional integration across core brain networks in migraine without aura.

Science.gov (United States)

Yu, Dahua; Yuan, Kai; Luo, Lin; Zhai, Jinquan; Bi, Yanzhi; Xue, Ting; Ren, Xiaoying; Zhang, Ming; Ren, Guoyin; Lu, Xiaoqi

2017-01-01

As a complex subjective experience, pain processing may be related to functional integration among intrinsic connectivity networks of migraine patients without aura. However, few study focused on the pattern alterations in the intrinsic connectivity networks of migraine patients without aura. Thirty-one migraine patients without aura and 31 age- and education-matched healthy controls participated in this study. After identifying the default mode network, central executive network and salience network as core intrinsic connectivity networks by using independent component analysis, functional connectivity, and effective connectivity during the resting state were used to investigate the abnormalities in intrinsic connectivity network interactions. Migraine patients without aura showed decreased functional connectivity among intrinsic connectivity networks compared with healthy controls. The strength of causal influences from the right frontoinsular cortex to the right anterior cingulate cortex became weaker, and the right frontoinsular cortex to the right medial prefrontal cortex became stronger in migraine patients without aura. These changes suggested that the salience network may play a major role in the pathophysiological features of migraine patients without aura and helped us to synthesize previous findings into an aberrant network dynamical framework.

A comprehensive overview of the climatological composition of the Asian summer monsoon anticyclone based on 10 years of Aura Microwave Limb Sounder measurements

Science.gov (United States)

Santee, M. L.; Manney, G. L.; Livesey, N. J.; Schwartz, M. J.; Neu, J. L.; Read, W. G.

2017-05-01

Intense deep convection associated with the Asian summer monsoon (ASM) lofts surface pollutants to the upper troposphere/lower stratosphere (UTLS), where strong winds and long chemical lifetimes allow intercontinental transport, affecting atmospheric composition around the globe. The Aura Microwave Limb Sounder (MLS), launched in 2004, makes simultaneous colocated measurements of trace gases and cloud ice water content (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, extensive measurement suite, and insensitivity to aerosol and most clouds of Aura MLS to characterize the climatological (2005-2014) composition of the ASM anticyclone throughout its annual life cycle. We use version 4 MLS data to quantify spatial and temporal variations in both tropospheric (H2O, CO, CH3Cl, CH3CN, CH3OH) and stratospheric (O3, HNO3, HCl) tracers on four potential temperature surfaces (350-410 K). Inside the mature anticyclone, all species exhibit substantial changes, not only from their premonsoon distributions in the ASM region but also from their summertime distributions in the rest of the hemisphere. Different tracers exhibit dissimilar seasonal evolution, and the exact location and timing of their extreme values vary. Although individual aspects of the anticyclone have been described previously, we present a uniquely comprehensive overview of the climatological seasonal evolution of the ASM and its impact on UTLS composition. This work provides valuable context for planned in situ measurements as well as a benchmark for model evaluation and future investigations of interannual variability and long-term changes in monsoon processes.

Prospective testing of ICHD-3 beta diagnostic criteria for migraine with aura and migraine with typical aura in patients with transient ischemic attacks

DEFF Research Database (Denmark)

Lebedeva, Elena R; Gurary, Natalia M; Gilev, Denis V

2018-01-01

Introduction The International Classification of Headache Disorders 3rd edition beta (ICHD-3 beta) gave alternative diagnostic criteria for 1.2 migraine with aura (MA) and 1.2.1 migraine with typical aura (MTA) in the appendix. The latter were presumed to better differentiate transient ischemic...

Tropospheric ozone using an emission tagging technique in the CAM-Chem and WRF-Chem models

Science.gov (United States)

Lupascu, A.; Coates, J.; Zhu, S.; Butler, T. M.

2017-12-01

Tropospheric ozone is a short-lived climate forcing pollutant. High concentration of ozone can affect human health (cardiorespiratory and increased mortality due to long-term exposure), and also it damages crops. Attributing ozone concentrations to the contributions from different sources would indicate the effects of locally emitted or transported precursors on ozone levels in specific regions. This information could be used as an important component of the design of emissions reduction strategies by indicating which emission sources could be targeted for effective reductions, thus reducing the burden of ozone pollution. Using a "tagging" approach within the CAM-Chem (global) and WRF-Chem (regional) models, we can quantify the contribution of individual emission of NOx and VOC precursors on air quality. Hence, when precursor emissions of NOx are tagged, we have seen that the largest contributors on ozone levels are the anthropogenic sources, while in the case of precursor emissions of VOCs, the biogenic sources and methane account for more than 50% of ozone levels. Further, we have extended the NOx tagging method in order to investigate continental source region contributions to concentrations of ozone over various receptor regions over the globe, with a zoom over Europe. In general, summertime maximum ozone in most receptor regions is largely attributable to local emissions of anthropogenic NOx and biogenic VOC. During the rest of the year, especially during springtime, ozone in most receptor regions shows stronger influences from anthropogenic emissions of NOx and VOC in remote source regions.

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

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...... 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...

Exploding head syndrome followed by sleep paralysis: a rare migraine aura.

Science.gov (United States)

Evans, Randolph W

2006-04-01

A 26-year-old patient is described with a unique migraine aura. She described an 8-year history of episodes occurring 1 to 2 times yearly of exploding head syndrome followed by sleep paralysis followed by a migraine headache. She also had identical headaches without aura about once per week. Both aura symptoms, which may occur in the brainstem, resulted in activation of the trigeminovascular system through an unknown mechanism.

Uncertainties in models of tropospheric ozone based on Monte Carlo analysis: Tropospheric ozone burdens, atmospheric lifetimes and surface distributions

Science.gov (United States)

Derwent, Richard G.; Parrish, David D.; Galbally, Ian E.; Stevenson, David S.; Doherty, Ruth M.; Naik, Vaishali; Young, Paul J.

2018-05-01

Recognising that global tropospheric ozone models have many uncertain input parameters, an attempt has been made to employ Monte Carlo sampling to quantify the uncertainties in model output that arise from global tropospheric ozone precursor emissions and from ozone production and destruction in a global Lagrangian chemistry-transport model. Ninety eight quasi-randomly Monte Carlo sampled model runs were completed and the uncertainties were quantified in tropospheric burdens and lifetimes of ozone, carbon monoxide and methane, together with the surface distribution and seasonal cycle in ozone. The results have shown a satisfactory degree of convergence and provide a first estimate of the likely uncertainties in tropospheric ozone model outputs. There are likely to be diminishing returns in carrying out many more Monte Carlo runs in order to refine further these outputs. Uncertainties due to model formulation were separately addressed using the results from 14 Atmospheric Chemistry Coupled Climate Model Intercomparison Project (ACCMIP) chemistry-climate models. The 95% confidence ranges surrounding the ACCMIP model burdens and lifetimes for ozone, carbon monoxide and methane were somewhat smaller than for the Monte Carlo estimates. This reflected the situation where the ACCMIP models used harmonised emissions data and differed only in their meteorological data and model formulations whereas a conscious effort was made to describe the uncertainties in the ozone precursor emissions and in the kinetic and photochemical data in the Monte Carlo runs. Attention was focussed on the model predictions of the ozone seasonal cycles at three marine boundary layer stations: Mace Head, Ireland, Trinidad Head, California and Cape Grim, Tasmania. Despite comprehensively addressing the uncertainties due to global emissions and ozone sources and sinks, none of the Monte Carlo runs were able to generate seasonal cycles that matched the observations at all three MBL stations. Although

Cluster-like headache aura status

NARCIS (Netherlands)

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

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.

Tropospheric VOC measurements by PTR-MS

International Nuclear Information System (INIS)

Hansel, A.; Wisthaler, A.; Graus, M.; Grabmer, W.

2002-01-01

Full text: O 3 is formed photochemically from the photolysis of NO 2 , and because O 3 reacts rapidly with NO these reactions result in a photoequilibrium between NO, NO 2 with no net formation or loss of O 3 , However, in the presence of volatile organic compounds (VOCs), the degradation reactions of VOCs lead to the formation of intermediate peroxy radicals which react with NO, converting NO to NO 2 , which then photolyze to form O 3 . Thus, in order to understand quantitatively tropospheric ozone chemistry, it is necessary to know the VOC distribution within the troposphere as well as VOC fluxes from individual sources. Examples will be presented how the use of Proton Transfer Reaction Mass Spectrometry (PTR-MS) has enhanced our understanding of anthropogenic VOC emissions, biosphere-atmosphere exchange processes, and photochemical processing of both anthropogenic and biogenic VOCs in the troposphere. (author)

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. Wiley Periodicals, Inc. © 2015 International League Against Epilepsy.

The Tropospheric Ozone Assessment Report (TOAR): A community-wide effort to quantify tropospheric ozone in a rapidly changing world

Science.gov (United States)

Cooper, O. R.; Schultz, M.; Paoletti, E.; Galbally, I. E.; Naja, M. K.; Tarasick, D. W.; Evans, M. J.; Thompson, A. M.

2017-12-01

Tropospheric ozone is a greenhouse gas and pollutant detrimental to human health and crop and ecosystem productivity. Since 1990 a large portion of the anthropogenic emissions that react in the atmosphere to produce ozone has shifted from North America and Europe to Asia. This rapid shift, coupled with limited ozone monitoring in developing nations, left scientists unable to answer the most basic questions: Which regions of the world have the greatest human and plant exposure to ozone pollution? Is ozone continuing to decline in nations with strong emissions controls? To what extent is ozone increasing in the developing world? How can the atmospheric sciences community facilitate access to the ozone metrics necessary for quantifying ozone's impact on human health and crop/ecosystem productivity? To answer these questions the International Global Atmospheric Chemistry Project (IGAC) initiated the Tropospheric Ozone Assessment Report (TOAR). With over 220 member scientists and air quality specialists from 36 nations, TOAR's mission is to provide the research community with an up-to-date scientific assessment of tropospheric ozone's global distribution and trends from the surface to the tropopause. TOAR has also built the world's largest database of surface ozone observations and generated ozone exposure and dose metrics at thousands of measurement sites around the world, freely accessible for research on the global-scale impact of ozone on climate, human health and crop/ecosystem productivity. Plots of these metrics show the regions of the world with the greatest ozone exposure for humans and crops/ecosystems, at least in areas where observations are available. The results also highlight regions where air quality is improving and where it has degraded. TOAR has also conducted the first intercomparison of tropospheric column ozone from ozonesondes and multiple satellite instruments, which provide similar estimates of the present-day tropospheric ozone burden.

On the methodology of drug trials in migraine with aura

DEFF Research Database (Denmark)

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

2010-01-01

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....

Heterogenous migraine aura symptoms correlate with visual cortex functional magnetic resonance imaging responses

DEFF Research Database (Denmark)

Arngrim, Nanna; Hougaard, Anders; Ahmadi, Khazar

2017-01-01

Objective: Migraine aura is sparsely studied due to the highly challenging task of capturing patients during aura. Cortical spreading depression (CSD) is likely the underlying phenomenon of aura. The possible correlation between the multifaceted phenomenology of aura symptoms and the effects of CSD...... on the brain has not been ascertained. Methods: Five migraine patients were studied during various forms of aura symptoms induced by hypoxia, sham hypoxia, or physical exercise with concurrent photostimulation. The blood oxygenation level–dependent (BOLD) functional magnetic resonance imaging (fMRI) signal...... response to visual stimulation was measured in retinotopic mapping–defined visual cortex areas V1 to V4. Results: We found reduced BOLD response in patients reporting scotoma and increased response in patients who only experienced positive symptoms. Furthermore, patients with bilateral visual symptoms had...

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.

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.

Effects of tonabersat on migraine with aura: a randomised, double-blind, placebo-controlled crossover study

DEFF Research Database (Denmark)

Hauge, Anne W; Asghar, Mohammed S; Schytz, Henrik W

2009-01-01

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......, of whom 31 were included in the statistical analysis of efficacy. Median (IQR) attacks of aura were reduced from 3.2 (1.0-5.0) per 12 weeks on placebo to 1.0 (0-3.0) on tonabersat (p=0.01), whereas the other primary outcome measure, median migraine headache days with or without aura, was not significantly...... 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....

Migraine aura: retracting particle-like waves in weakly susceptible cortex.

Directory of Open Access Journals (Sweden)

Markus A Dahlem

Full Text Available Cortical spreading depression (SD has been suggested to underlie migraine aura. Despite a precise match in speed, the spatio-temporal patterns of SD observed in animal cortex and aura symptoms mapped to the cortical surface ordinarily differ in aspects of size and shape. We show that this mismatch is reconciled by utilizing that both pattern types bifurcate from an instability point of generic reaction-diffusion models. To classify these spatio-temporal pattern we suggest a susceptibility scale having the value sigma = 1 at the instability point. We predict that human cortex is only weakly susceptible to SD (sigma1, and potentially silent aura occurring below a second bifurcation point at sigma = 0 on the susceptible scale.

Profiles of CH4, HDO, H2O, and N2O with improved lower tropospheric vertical resolution from Aura TES radiances

Directory of Open Access Journals (Sweden)

D. Noone

2012-02-01

Full Text Available Thermal infrared (IR radiances measured near 8 microns contain information about the vertical distribution of water vapor (H2O, the water isotopologue HDO, and methane (CH4, key gases in the water and carbon cycles. Previous versions (Version 4 or less of the TES profile retrieval algorithm used a "spectral-window" approach to minimize uncertainty from interfering species at the expense of reduced vertical resolution and sensitivity. In this manuscript we document changes to the vertical resolution and uncertainties of the TES version 5 retrieval algorithm. In this version (Version 5, joint estimates of H2O, HDO, CH4 and nitrous oxide (N2O are made using radiances from almost the entire spectral region between 1100 cm−1 and 1330 cm−1. The TES retrieval constraints are also modified in order to better use this information. The new H2O estimates show improved vertical resolution in the lower troposphere and boundary layer, while the new HDO/H2O estimates can now profile the HDO/H2O ratio between 925 hPa and 450 hPa in the tropics and during summertime at high latitudes. The new retrievals are now sensitive to methane in the free troposphere between 800 and 150 mb with peak sensitivity near 500 hPa; whereas in previous versions the sensitivity peaked at 200 hPa. However, the upper troposphere methane concentrations are biased high relative to the lower troposphere by approximately 4% on average. This bias is likely related to temperature, calibration, and/or methane spectroscopy errors. This bias can be mitigated by normalizing the CH4 estimate by the ratio of the N2O estimate relative to the N2O prior, under the assumption that the same systematic error affects both the N2O and CH4 estimates. We demonstrate that applying this ratio theoretically reduces the CH4 estimate for non-retrieved parameters that jointly affect both the N2O and CH4 estimates. The relative upper troposphere to lower troposphere bias is approximately 2.8% after this bias

Multi-source SO2 emission retrievals and consistency of satellite and surface measurements with reported emissions

NARCIS (Netherlands)

Fioletov, V.; McLinden, C.A.; Kharol, S.K.; Krotkov, N.A.; Li, C.; Joiner, J.; Moran, M.D.; Vet, R.; Visschedijk, A.J.H.; Denier Van Der Gon, H.A.C.

2017-01-01

Reported sulfur dioxide (SO2) emissions from US and Canadian sources have declined dramatically since the 1990s as a result of emission control measures. Observations from the Ozone Monitoring Instrument (OMI) on NASA's Aura satellite and ground-based in situ measurements are examined to verify

Migraine with visual aura associated with thicker visual cortex

DEFF Research Database (Denmark)

Gaist, David; Hougaard, Anders; Garde, Ellen

2018-01-01

Until recent years it was believed that migraine with aura was a disorder causing intermittent neurological symptoms, with no impact on brain structure. However, recent MRI studies have reported increased cortical thickness of visual and somatosensory areas in patients with migraine with aura...... number of subjects. In this cross-sectional study, we recruited females aged 30-60 years from the nationwide Danish Twin Registry. Brain MRI of females with migraine with aura (patients), their co-twins, and unrelated migraine-free twins (controls) were performed at a single centre and assessed...... for cortical thickness in predefined cortical areas (V1, V2, V3A, MT, somatosensory cortex), blinded to headache diagnoses. The difference in cortical thickness between patients and controls adjusted for age, and other potential confounders was assessed. Comparisons of twin pairs discordant for migraine...

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

Applications of Satellite Observations of Tropospheric Composition

Science.gov (United States)

Monks, Paul S.; Beirle, Steffen

A striking feature of the field of tropospheric composition is the sheer number of chemical species that have been detected and measured with satellite instruments. The measurements have found application both in atmospheric chemistry itself, providing evidence, for example, of unexpected cryochemistry in the Arctic regions, and also in environmental monitoring with, for example, the observed growth in NO2 emissions over eastern Asia. Chapter 8 gives an overview of the utility of satellite observations for measuring tropospheric composition, dealing with each of the many compounds seen in detail. A comprehensive compound by compound table of the many studies performed is a most useful feature.

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)

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

1998-12-31

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)

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

. CONCLUSION: These findings are consistent with variable involvement of different brain regions during a migraine attack. The variable occurrence of nausea, and phonophobia in conjunction with photophobia, both defining features of migraine, may be an important consideration in designing clinical studies......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...... 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...

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 (NO_x 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.

A cloud-ozone data product from Aura OMI and MLS satellite measurements

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J. R. Ziemke

2017-11-01

Full Text Available Ozone within deep convective clouds is controlled by several factors involving photochemical reactions and transport. Gas-phase photochemical reactions and heterogeneous surface chemical reactions involving ice, water particles, and aerosols inside the clouds all contribute to the distribution and net production and loss of ozone. Ozone in clouds is also dependent on convective transport that carries low-troposphere/boundary-layer ozone and ozone precursors upward into the clouds. Characterizing ozone in thick clouds is an important step for quantifying relationships of ozone with tropospheric H2O, OH production, and cloud microphysics/transport properties. Although measuring ozone in deep convective clouds from either aircraft or balloon ozonesondes is largely impossible due to extreme meteorological conditions associated with these clouds, it is possible to estimate ozone in thick clouds using backscattered solar UV radiation measured by satellite instruments. Our study combines Aura Ozone Monitoring Instrument (OMI and Microwave Limb Sounder (MLS satellite measurements to generate a new research product of monthly-mean ozone concentrations in deep convective clouds between 30° S and 30° N for October 2004–April 2016. These measurements represent mean ozone concentration primarily in the upper levels of thick clouds and reveal key features of cloud ozone including: persistent low ozone concentrations in the tropical Pacific of  ∼ 10 ppbv or less; concentrations of up to 60 pphv or greater over landmass regions of South America, southern Africa, Australia, and India/east Asia; connections with tropical ENSO events; and intraseasonal/Madden–Julian oscillation variability. Analysis of OMI aerosol measurements suggests a cause and effect relation between boundary-layer pollution and elevated ozone inside thick clouds over landmass regions including southern Africa and India/east Asia.

Future changes in large-scale transport and stratosphere-troposphere exchange

Science.gov (United States)

Abalos, M.; Randel, W. J.; Kinnison, D. E.; Garcia, R. R.

2017-12-01

Future changes in large-scale transport are investigated in long-term (1955-2099) simulations of the Community Earth System Model - Whole Atmosphere Community Climate Model (CESM-WACCM) under an RCP6.0 climate change scenario. We examine artificial passive tracers in order to isolate transport changes from future changes in emissions and chemical processes. The model suggests enhanced stratosphere-troposphere exchange in both directions (STE), with decreasing tropospheric and increasing stratospheric tracer concentrations in the troposphere. Changes in the different transport processes are evaluated using the Transformed Eulerian Mean continuity equation, including parameterized convective transport. Dynamical changes associated with the rise of the tropopause height are shown to play a crucial role on future transport trends.

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.

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.

Migraine aura pathophysiology: the role of blood vessels and microembolisation

OpenAIRE

Dalkara, Turgay; Nozari, Ala; Moskowitz, Michael A

2010-01-01

Migraine attacks with auras are sometimes associated with underlying hereditary or acquired cerebrovascular disorders. A unifying pathophysiological explanation linking migraine to these conditions has been diffcult to identify. On the basis of genetic and epidemiological evidence, we suggest that changes in blood vessels, hypoperfusion disorders, and microembolisation can cause neurovascular dysfunction and evoke cortical spreading depression, an event that is widely thought to underlie aura...

PM2.5 and tropospheric ozone in China: overview of situation and responses

Science.gov (United States)

Zhang, Hua

This work reviewed the observational status of PM2.5 and tropospheric ozone in China. It told us the observational facts on the ratios of typical types of aerosol components to the total PM2.5/PM10, and daily and seasonal change of near surface ozone concentration at different cities of China; the global concentration distribution of tropospheric ozone observed by satellite in 2010-2013 was also given for comparison; the PM2.5 concentration distribution and their seasonal change in China region were simulated by an aerosol chemistry-global climate modeling system. Different contribution from five kinds of aerosols to the simulated PM2.5 was analyzed. Then, it linked the emissions of aerosol and greenhouse gases and their radiative forcing and thus gave their climatic effect by reducing their emissions on the basis of most recently published IPCC AR5. Finally it suggested policies on reducing emissions of short-lived climate pollutants (SLCPs) (such as PM2.5 and tropospheric ozone) in China from protecting both climate and environment.

Changes in SO2 and NO2 Pollution over the Past Decade Observed by Aura OMI

Science.gov (United States)

Krotkov, N. A.; Li, C.; Lamsal, L. N.; Celarier, E. A.; Marchenko, S. V.; Swartz, W.; Bucsela, E. J.; Fioletov, V.; McLinden, C. A.; Joiner, J.; Bhartia, P. K.; Duncan, B. N.; Dickerson, R. R.

2014-12-01

The Ozone Monitoring Instrument (OMI), a NASA partnership with the Netherlands and Finland, flies on the EOS Aura satellite and uses reflected sunlight to measure 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 among USEPA designated criteria pollutants, posing serious threats to human health and the environment (e.g., acid rain, plant damage, and reduced visibility). A new generation of the OMI standard SO2 and NO2 products (based on critically improved DOAS spectral fitting for NO2 and innovative Principal Component Analysis method for SO2) provides a valuable dataset for studying anthropogenic pollution on local to global scales. Here we highlight some of the OMI observed long-term changes in air quality over several regions. Over the US, average NO2 and SO2 pollution levels have 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 NO2 and SO2 pollution over Europe. Over China OMI observed a ~ 60% increase in NO2 pollution between 2005 and 2013, despite a temporary 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 new large coal power plants have been built in recent years. We expect that further improvements in the OMI NO2 and SO2 products will allow more robust quantification of long-term trends in local to global air quality.

Hydrological controls on the tropospheric ozone greenhouse gas effect

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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.

Eleven years of tropospheric NO2 measured by GOME, SCIAMACHY and OMI

Science.gov (United States)

Eskes, H.; Boersma, F.; Dirksen, R.; van der A, R.; Veefkind, P.; Levelt, P.; Brinksma, E.; van Roozendael, M.; de Smedt, I.; Gleason, J.

2006-12-01

Based on measurements of GOME on ESA ERS-2, SCIAMACHY on ESA-ENVISAT, and Ozone Monitoring Instrument (OMI) on the NASA EOS-Aura satellite there is now a unique 11-year dataset of global tropospheric nitrogen dioxide measurements from space. The retrieval approach consists of two steps. The first step is an application of the DOAS (Differential Optical Absorption Spectroscopy) approach which delivers the total absorption optical thickness along the light path (the slant column). For GOME and SCIAMACHY this is based on the DOAS implementation developed by BIRA/IASB. For OMI the DOAS implementation was developed in a collaboration between KNMI and NASA. The second retrieval step, developed at KNMI, estimates the tropospheric vertical column of NO2 based on the slant column, cloud fraction and cloud top height retrieval, stratospheric column estimates derived from a data assimilation approach and vertical profile estimates from space-time collocated profiles from the TM chemistry-transport model. The second step was applied with only minor modifications to all three instruments to generate a uniform 11-year data set. In our talk we will address the following topics: - A short summary of the retrieval approach and results - Comparisons with other retrievals - Comparisons with global and regional-scale models - OMI-SCIAMACHY and SCIAMACHY-GOME comparisons - Validation with independent measurements - Trend studies of NO2 for the past 11 years

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

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 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.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.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.An incomplete circle of Willis is more common in migraine with aura subjects than controls, and is associated with alterations in cerebral blood flow.

Auras in temporal lobe epilepsy with hippocampal sclerosis: relation to seizure focus laterality and post surgical outcome.

Science.gov (United States)

Ferrari-Marinho, Taíssa; Caboclo, Luís Otávio S F; Marinho, Murilo M; Centeno, Ricardo S; Neves, Rafael S C; Santana, Maria Teresa C G; Brito, Fernanda S; Junior, Henrique Carrete; Yacubian, Elza Márcia T

2012-05-01

We examined the relationship between presence and frequency of different types of auras and side of lesion and post surgical outcomes in 205 patients with medically intractable mesial temporal lobe epilepsy (MTLE) with unilateral hippocampal sclerosis (HS). With respect to the number of auras, multiple auras were not associated with side of lesion (p=0.551). The side of HS was not associated with the type of auras reported. One hundred fifty-seven patients were operated. The occurrence of multiple auras was not associated with post-surgical outcome (p=0.740). The presence of extratemporal auras was significantly higher in patients with poor outcome. In conclusion, this study suggests that the presence of extratemporal auras in patients with MTLE-HS possibly reflects extratemporal epileptogenicity in these patients, who otherwise showed features suggestive of TLE. Therefore, TLE-HS patients undergoing pre-surgical evaluation and presenting clinical symptoms suggestive of extratemporal involvement should be more extensively evaluated to avoid incomplete resection of the epileptogenic zone. Copyright © 2012 Elsevier Inc. All rights reserved.

Grey zones in the diagnosis of adult migraine without aura based on the International Classification of Headache Disorders-III beta: exploring the covariates of possible migraine without aura.

Science.gov (United States)

Ozge, Aynur; Aydinlar, Elif; Tasdelen, Bahar

2015-01-01

Exploring clinical characteristics and migraine covariates may be useful in the diagnosis of migraine without aura. To evaluate the diagnostic value of the International Classification of Headache Disorders (ICHD)-III beta-based diagnosis of migraine without aura; to explore the covariates of possible migraine without aura using an analysis of grey zones in this area; and, finally, to make suggestions for the final version of the ICHD-III. A total of 1365 patients (mean [± SD] age 38.5±10.4 years, 82.8% female) diagnosed with migraine without aura according to the criteria of the ICHD-III beta were included in the present tertiary care-based retrospective study. Patients meeting all of the criteria of the ICHD-III beta were classified as having full migraine without aura, while those who did not meet one, two or ≥3 of the diagnostic criteria were classified as zones I, II and III, respectively. The diagnostic value of the clinical characteristics and covariates of migraine were determined. Full migraine without aura was evident in 25.7% of the migraineurs. A higher likelihood of zone I classification was shown for an attack lasting 4 h to 72 h (OR 1.560; P=0.002), with pulsating quality (OR 4.096; P<0.001), concomitant nausea⁄vomiting (OR 2.300; P<0.001) and photophobia⁄phonophobia (OR 4.865; P<0.001). The first-rank determinants for full migraine without aura were sleep irregularities (OR 1.596; P=0.005) and periodic vomiting (OR 1.464; P=0.026). However, even if not mentioned in ICHD-III beta, the authors determined that motion sickness, abdominal pain or infantile colic attacks in childhood, associated dizziness and osmophobia have important diagnostic value. In cases that do not fulfill all of the diagnostic criteria although they are largely consistent with the characteristics of migraine in clinical terms, the authors believe that a history of infantile colic; periodic vomiting (but not periodic vomiting syndrome); recurrent abdominal pain; the

Upper-tropospheric CO and O3 budget during the Asian summer monsoon

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B. Barret

2016-07-01

Full Text Available 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

Vertical distribution and sources of tropospheric ozone over South China in spring 2004: Ozonesonde measurements and modeling analysis

Science.gov (United States)

Zhang, Y.; Liu, H.; Crawford, J. H.; Considine, D. B.; Chan, C.; Scientific Team Of Tapto

2010-12-01

The Transport of Air Pollutant and Tropospheric Ozone over China (TAPTO-China) science initiative is a two-year (TAPTO 2004 and 2005) field measurement campaign to help improve our understanding of the physical and chemical processes that control the tropospheric ozone budget over the Chinese subcontinent (including the Asian Pacific rim) and its surrounding SE Asia. In this paper, we use two state-of-the-art 3-D global chemical transport models (GEOS-Chem and Global Modeling Initiative or GMI) to examine the characteristics of vertical distribution and quantify the sources of tropospheric ozone by analysis of TAPTO in-situ ozonesonde data obtained at five stations in South China during spring (April and May) 2004: Lin’an (30.30N, 119.75E), Tengchong (25.01N, 98.30E), Taipei (25.0N, 121.3E), Hong Kong (22.21N, 114.30E) and Sanya (18.21N, 110.31E). The observed tropospheric ozone concentrations show strong spatial and temporal variability, which is largely captured by the models. The models simulate well the observed vertical gradients of tropospheric ozone at higher latitudes but are too low at lower latitudes. Model tagged ozone simulations suggest that stratosphere has a large impact on the upper and middle troposphere (UT/MT) at Lin’an and Tengchong. Continental SE Asian biomass burning emissions are maximum in March but still contribute significantly to the photochemical production of tropopheric ozone in South China in early April. Asian anthropogenic emissions are the major contribution to lower tropospheric ozone at all stations. On the other hand, there are episodes of influence from European/North American anthropogenic emissions. For example, model tagged ozone simulations show that over Lin’an in April 2004, stratosphere contributes 20% (13 ppbv) at 5 km, Asian boundary layer contributes 70% (46 ppbv) to ozone in the boundary layer, European boundary layer contributes 5% (3-4 ppbv) at 1.2 km, and North American boundary layer contributes 4.5% (3

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;

Neurophysiology of visual aura in migraine

International Nuclear Information System (INIS)

Shibata, Koichi

2007-01-01

Visual processing in migraine has been targeted because the visual symptoms that are commonly associated with attack, either in the form of aura or other more subtle symptoms, indicate that the visual pathways are involved in migrainous pathophysiology. The visual aura of the migraine attack has been explained by the cortical spreading depression (CSD) of Leao, neuroelectric event beginning in the occipital cortex and propagating into contiguous brain region. Clinical observations suggest that hyperexcitability occurs not only during the attack, typically in the form of photophobia, but also between attacks. Numerous human neuroimaging, neurophysiological and psychophysical studies have identified differences in cortical visual processing in migraine. The possibility of imaging the typical visual aura with BOLD functional MRI has revealed multiple neurovascular events in the occipital cortex within a single attack that closely resemble CSD. As transient synchronized neuronal excitation precedes CSD, changes in cortical excitability underlie the migraine attack. Independent evidence for altered neuronal excitability in migraineurs between attacks emerges from visual evoked potentials (VEPs) and transcranial magnetic stimulation (TMS), recordings of cortical potentials and psychophysics. Recently, both TMS and psychophysical studies measuring visual performance in migraineurs have used measures which presumably measure primary visual (V1) and visual association cortex. Our VEP and blink reflex study showed that migraine patients exhibiting allodynia might show central sensitization of braistem trigeminal neuron and had contrast modulation dysfunction during the cortical visual processing of V1 and visual association cortex in-between attacks. In pathophysiology of migraine, these neurophysiological and psychophysical studies indicate that abnormal visual and trigeminal hyperexcitability might persist between migraine attacks. The influence of migraine on cortical

Characteristics of intercontinental transport of tropospheric ozone from Africa to Asia

Science.gov (United States)

Han, Han; Liu, Jane; Yuan, Huiling; Zhuang, Bingliang; Zhu, Ye; Wu, Yue; Yan, Yuhan; Ding, Aijun

2018-03-01

In this study, we characterize the transport of ozone from Africa to Asia through the analysis of the simulations of a global chemical transport model, GEOS-Chem, from 1987 to 2006. The receptor region Asia is defined within 5-60° N and 60-145° E, while the source region Africa is within 35° S-15° N and 20° W-55° E and within 15-35° N and 20° W-30° E. The ozone generated in the African troposphere from both natural and anthropogenic sources is tracked through tagged ozone simulation. Combining this with analysis of trajectory simulations using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model, we find that the upper branch of the Hadley cell connects with the subtropical westerlies in the Northern Hemisphere (NH) to form a primary transport pathway from Africa to Asia in the middle and upper troposphere throughout the year. The Somali jet that runs from eastern Africa near the equator to the Indian subcontinent in the lower troposphere is the second pathway that appears only in NH summer. The influence of African ozone mainly appears over Asia south of 40° N. The influence shows strong seasonality, varying with latitude, longitude, and altitude. In the Asian upper troposphere, imported African ozone is largest from March to May around 30° N (12-16 ppbv) and lowest during July-October around 10° N ( ˜ 2 ppbv). In the Asian middle and lower troposphere, imported African ozone peaks in NH winter between 20 and 25° N. Over 5-40° N, the mean fractional contribution of imported African ozone to the overall ozone concentrations in Asia is largest during NH winter in the middle troposphere ( ˜ 18 %) and lowest in NH summer throughout the tropospheric column ( ˜ 6 %). This seasonality mainly results from the collective effects of the ozone precursor emissions in Africa and meteorology and chemistry in Africa, in Asia and along the transport pathways. The seasonal swing of the Hadley circulation and subtropical westerlies along the

MLS/Aura L2 Geopotential Height V003

Data.gov (United States)

National Aeronautics and Space Administration — ML2GPH is the EOS Aura Microwave Limb Sounder (MLS) standard product for geopotential height derived from radiances measured by the 118 and 240 GHz radiometers. The...

MLS/Aura L2 Geopotential Height V002

Data.gov (United States)

National Aeronautics and Space Administration — ML2GPH is the EOS Aura Microwave Limb Sounder (MLS) standard product for geopotential height derived from radiances measured by the 118 and 240 GHz radiometers. The...

Aura, Self, and Aesthetic Experience

OpenAIRE

Marshall Battani

2011-01-01

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 de...

OMI/Aura Formaldehyde (HCHO) Total Column Global 0.25deg Lat/Lon Grid V003

Data.gov (United States)

National Aeronautics and Space Administration — The Version-3 Aura-OMI Formaldehyde Product OMHCHOG is now available (http://disc.gsfc.nasa.gov/Aura/OMI/omhchog_v003.shtml) from the NASA Goddard Earth Sciences...

Persistent Visual Aura following Catheter Ablation in a Patient with WPW Syndrome

Directory of Open Access Journals (Sweden)

Shinichi Koyama

2007-01-01

Full Text Available We report a patient who has had persistent visual disturbances since she underwent catheter ablation to treat her Wolff-Parkinson-White (WPW syndrome. We examined her visual symptoms carefully and quantitatively by means of our newly developed method combining image-processing and psychophysics. We first simulated the patient’s visual symptoms using image-processing techniques. Since the simulation indicated that she would be very sensitive to the edges of the visual stimuli, we evaluated her sensitivity to the edges using psychophysics. The results indicated that she was hypersensitive to the clear-cut edges of the visual stimuli. Her visual symptoms were very similar to those of visual aura of migraine, rather than those of photosensitive epilepsy. Magnetic resonance imaging (MRI and single photon emission computed tomography (SPECT, electroenchepalogram (EEG, and visual-evoked potentials (VEP in the patient were normal. No abnormalities in her fundus, visual field, or electroretinogram were found, either. Transesophageal echocardiography with bubble study indicated that she had a preexisting right-to-left shunt. We hypothesize that visual aura of migraine was triggered and made persistent by the catheter ablation in this patient. Although the relationship between migraine, catheter ablation, and right-to-left shunts is unknown, previous studies on the transcatheter closure of patent foramen ovale suggest a possible link between them. Catheter ablation in patients with migraine and preexisting shunts may lead to exacerbations in migraine symptoms.

What's NEW at the GES DISC: Evolution of Data Management and Services for Aura Mission and Beyond

Science.gov (United States)

Wei, Jennifer

2016-01-01

GES DISC world. Aura data usage and trend. Aura data users requests. GES DISC update (before/after); New Access method (ftp to http) with Earthdata Login System, New Website (DISC/Mirador to New Interface), New Giovanni (Giovanni to Now Federated). GES DISC support beyond Aura Mission; Multi-sensor coincident data subsets, Level 2 support (Sub-setter, Visualization), Data List.

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.

Tropospheric effects of energy conversion

International Nuclear Information System (INIS)

Derwent, R.G.

1992-01-01

The tropospheric concentrations of a number of trace gases are increasing due to man's activities. For some trace gases, their atmospheric life cycles are not fully understood and it is difficult to be certain about the role of man's activities. Emissions from the energy industries and energy conversion processes represent an important subset of source terms in these life cycles, along with agriculture, deforestation, cement manufacture, biomass burning, process industries and natural biospheric processes. Global Warming Potentials (GWPs) allow the tropospheric effects of a range of climate forcing trace gases to be assessed on a comparable basis. If a short term view of the commitment to global warming is adopted then the contribution from other trace gases may approach and exceed that of carbon dioxide, itself. Over longer time horizons, the long atmospheric lifetime of carbon dioxide shows through as a major influence and the contributions from the other trace gases appear to be much smaller, representing an additional 13-18% contribution on top of that from CO 2 itself

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

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....

Epileptic aura and perception of self-control

DEFF Research Database (Denmark)

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

2015-01-01

OBJECTIVE: 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...

Quantifying the influence of boreal biomass burning emissions on tropospheric oxidant chemistry over the North Atlantic using BORTAS measurements

Science.gov (United States)

Parrington, Mark; Palmer, Paul I.; Rickard, Andrew; Young, Jennifer; Lewis, Ally; Lee, James; Henze, Daven; Tarasick, David; Hyer, Edward; Yantosca, Robert; Bowman, Kevin; Worden, John; Griffin, Debora; Franklin, Jonathan; Helmig, Detlev

2013-04-01

We use the GEOS-Chem chemistry transport model to quantify the impact of boreal biomass burning on tropospheric oxidant chemistry over the North Atlantic region during summer of 2011. The GEOS-Chem model is used at a spatial resolution of 1/2 degree latitude by 2/3 degree longitude for a domain covering eastern North America, the North Atlantic Ocean and western Europe. We initialise the model with biomass burning emissions from the Fire Locating and Monitoring of Burning Emissions (FLAMBE) inventory and use a modified chemical mechanism providing a detailed description of ozone photochemistry in boreal biomass burning outflow derived from the Master Chemical Mechanism (MCM). We evaluate the 3-D model distribution of ozone and tracers associated with biomass burning against measurements made by the UK FAAM BAe-146 research aircraft, ozonesondes, ground-based and satellite instruments as part of the BORTAS experiment between 12 July and 3 August 2011. We also use the GEOS-Chem model adjoint to fit the model to BORTAS measurements to analyse the sensitivity of the model chemical mechanism and ozone distribution to wildfire emissions in central Canada.

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.

Transportable lidar for the measurement of ozone concentration and flux profiles in the lower troposphere

International Nuclear Information System (INIS)

Zhao, Yanzeng; Howell, J.N.; Hardesty, R.M.

1992-01-01

In many areas of the United States, as well as in other industrial areas (such as Europe), elevated and potentially harmful levels of ozone are being measured during summer. Most of this ozone is photochemically produced. The relatively long lifetime of ozone allows industrially produced ozone to be transported on a hemispheric scale. Since the trends of tropospheric ozone are very likely dependent on the source strengths and distributions of the pollutants and the chemical/ transport process involved, a predictive understanding of tropospheric ozone climatology requires a focus on the chemical and transport processes that link regional emissions to hemispheric ozone trends and distributions. Of critical importance to these studies is a satisfactory data base of tropospheric ozone distribution from which global and regional tropospheric ozone climatology can be derived, and the processes controlling tropospheric ozone can be better understood. A transportable lidar for measuring ozone concentration and flux profiles in the lower troposphere is needed. One such system is being developed at the National Oceanic and Atmospheric Administration/Earth Resources Laboratory (NOAA/ERL) Wave Propagation Laboratory (WPL)

NMHC emissions from Asia: sources and transport

Science.gov (United States)

Shirai, T.; Blake, D. R.; Barletta, B.; Meinardi, S.; Rowland, F. S.; Chan, J. C.; Takegawa, N.; Kondo, Y.; Koike, M.; Kita, K.; Takigawa, M.; Kawakami, S.; Ogawa, T.

2002-12-01

Recent rapid industrialization and economic growth in Asia changed the industrial structure, land use, and people's lifestyle resulting in a dramatic change in the amount and composition of the gas emissions from Asia. Because emissions can be transported very rapidly once convected to the free troposphere, Asian emissions can affect both local and regional air quality and climate. To access the impact of changing emission from Asia, an airborne observation campaign PEACE (the Pacific Exploration of Asian Continental Emission) phase-A and B were conducted in January and April - May 2002, respectively, sponsored by NASDA (National Space Development Agency of Japan). The concentrations of NMHCs (nonmethanehydrocarbons) and halocarbons were obtained by whole air sampling and subsequent gas chromatography analyses in the laboratory. Quantified onboard the aircraft were CO, CO2, O3, NO, NO2, NOy, H2O, SO2, aerosols, and condensation nuclei. The experiment was conducted in the vicinity of Japan and PEACE-A and B represent the local winter and spring weather conditions. The trace gas distributions in the lower troposphere were often influenced by local pollution (i.e. from Japan, Korea) while those of the long-range transport (i.e. from Europe) were occasionally seen in the upper troposphere. This is confirmed by the airmass age estimation using the ratios of short-lived gases (i.e. C2H4) vs. more stable compounds (i.e. CO). Emissions from China were distinguished using data obtained from ground-based sampling and measurements. Transport from China was seen both in the lower troposphere and upper troposphere. Some case studies on source identification will be discussed.

Hydrogen Cyanide in the Upper Troposphere: GEM-AQ Simulation and Comparison with ACE-FTS Observations

Science.gov (United States)

Lupu, A.; Kaminski, J. W.; Neary, L.; McConnell, J. C.; Toyota, K.; Rinsland, C. P.; Bernath, P. F.; Walker, K. A.; Boone, C. D.; Nagahama, Y.;

Patients with migraine with aura have increased flow mediated dilation

Directory of Open Access Journals (Sweden)

Altamura Claudia

2010-03-01

Full Text Available Abstract Background Endothelium-derived nitric oxide (NO mediates the arterial dilation following a flow increase (i.e. flow-mediated dilation, FMD, easily assessed in the brachial artery. NO is also involved in cerebral hemodynamics and it is supposed to trigger vascular changes occurring during migraine. This study aimed at investigating whether migraine patients present an altered response to NO also in the peripheral artery system. Methods We enrolled 21 migraineurs (10 with aura [MwA], 11 without aura [MwoA], and 13 controls. FMD was evaluated with ultrasound in all subjects by measuring the percentage increase of the brachial artery diameter induced by hyperaemia reactive to sustained cuff inflation around the arm above systolic pressure. FMD values were then normalized for shear stress. Results Normalized FMD values were higher in patients with MwA (28.5 10-2%.s than in controls (9.0 10-2%.s and patients with MwoA (13.7 10-2%.s (p Conclusions Migraineurs with aura present an excessive arterial response to hyperaemia, likely as an effect of an increased sensitivity to endothelium-derived nitric oxide. This phenomenon observed peripherally might reflect similar characteristics in the cerebral circulation.

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

Time-dependent inversion estimates of global biomass-burning CO emissions using Measurement of Pollution in the Troposphere (MOPITT) measurements

Science.gov (United States)

Arellano, Avelino F.; Kasibhatla, Prasad S.; Giglio, Louis; van der Werf, Guido R.; Randerson, James T.; Collatz, G. James

2006-05-01

We present an inverse-modeling analysis of CO emissions using column CO retrievals from the Measurement of Pollution in the Troposphere (MOPITT) instrument and a global chemical transport model (GEOS-CHEM). We first focus on the information content of MOPITT CO column retrievals in terms of constraining CO emissions associated with biomass burning and fossil fuel/biofuel use. Our analysis shows that seasonal variation of biomass-burning CO emissions in Africa, South America, and Southeast Asia can be characterized using monthly mean MOPITT CO columns. For the fossil fuel/biofuel source category the derived monthly mean emission estimates are noisy even when the error statistics are accurately known, precluding a characterization of seasonal variations of regional CO emissions for this source category. The derived estimate of CO emissions from biomass burning in southern Africa during the June-July 2000 period is significantly higher than the prior estimate (prior, 34 Tg; posterior, 13 Tg). We also estimate that emissions are higher relative to the prior estimate in northern Africa during December 2000 to January 2001 and lower relative to the prior estimate in Central America and Oceania/Indonesia during April-May and September-October 2000, respectively. While these adjustments provide better agreement of the model with MOPITT CO column fields and with independent measurements of surface CO from National Oceanic and Atmospheric Administration Climate Monitoring and Diagnostics Laboratory at background sites in the Northern Hemisphere, some systematic differences between modeled and measured CO fields persist, including model overestimation of background surface CO in the Southern Hemisphere. Characterizing and accounting for underlying biases in the measurement model system are needed to improve the robustness of the top-down estimates.

Potential source of cerebral embolism in migraine with aura: a transcranial Doppler study.

Science.gov (United States)

Anzola, G P; Magoni, M; Guindani, M; Rozzini, L; Dalla Volta, G

1999-05-12

The recently found association between patent foramen ovale (PFO) and transient global amnesia (TGA) has suggested that paradoxical microembolization in the terminal vertebrobasilar territory might underlie at least some TGA cases. Migraine with visual aura is another paroxysmal disturbance in which a sudden dysfunction of cortical areas fed by the terminal branches of the basilar artery is believed to trigger the attack. Therefore we investigated the prevalence of PFO in a consecutive unselected cohort of migraine patients. To investigate the prevalence of PFO in a consecutive unselected cohort of migraine patients to search for a possible mechanism for the reported association of migraine with stroke. A total of 113 patients, consecutively referred by the Headache Outpatient Clinic for migraine with aura (MA+, mean age 34+/-12 years) were compared with 53 patients with migraine without aura (MA-, mean age 36+/-13 years) and with 25 age-matched nonmigraine subjects (mean age 31+/-10 years) selected from the hospital staff. PFO was assessed with transcranial Doppler sonography with IV injection of agitated saline, a technique that is 90% sensitive and 100% specific. The prevalence of PFO was 48% (54/113) in MA+ patients, 23% (12/53) in MA- patients, and 20% (5/25) in control subjects. The difference between MA+ and MA- patients was significant (odds ratio [OR] = 3.13, 95% confidence interval [CI] = 1.41 to 7.04, chi2 = 9.52,p = 0.002) as was the difference between MA+ patients and controls (OR = 3.66, 95% CI = 1.21 to 13.25, chi2 = 6.46, p = 0.01), whereas MA- patients did not differ from controls (OR = 1.17, 95% CI = 0.32 to 4.45, chi2 = 0.07). MRI was negative in 22 MA+ and 8 MA- patients. Patency of the foramen ovale is associated with migraine with aura but not with migraine without aura. The increased risk of stroke found in epidemiologic studies in patients with migraine with aura may be explained by an increased propensity to paradoxical cerebral embolism.

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.

Aerosol indirect effect on tropospheric ozone via lightning

Science.gov (United States)

Yuan, T.; Remer, L. A.; Bian, H.; Ziemke, J. R.; Albrecht, R. I.; Pickering, K. E.; Oreopoulos, L.; Goodman, S. J.; Yu, H.; Allen, D. J.

2012-12-01

Tropospheric ozone (O3) is a pollutant and major greenhouse gas and its radiative forcing is still uncertain. The unresolved difference between modeled and observed natural background O3 concentrations is a key source of the uncertainty. Here we demonstrate remarkable sensitivity of lightning activity to aerosol loading with lightning activity increasing more than 30 times per unit of aerosol optical depth over our study area. We provide observational evidence that indicates the observed increase in lightning activity is caused by the influx of aerosols from a volcano. Satellite data analyses suggest O3 is increased as a result of aerosol-induced increase in lightning and lightning produced NOx. Model simulations with prescribed lightning change corroborate the satellite data analysis. This aerosol-O3 connection is achieved via aerosol increasing lightning and thus lightning produced nitrogen oxides. This aerosol-lightning-ozone link provides a potential physical mechanism that may account for a part of the model-observation difference in background O3 concentration. More importantly, O3 production increase from this link is concentrated in the upper troposphere, where O3 is most efficient as a greenhouse gas. Both of these implications suggest a stronger O3 historical radiative forcing. This introduces a new pathway, through which increasing in aerosols from pre-industrial time to present day enhances tropospheric O3 production. Aerosol forcing thus has a warming component via its effect on O3 production. Sensitivity simulations suggest that 4-8% increase of tropospheric ozone, mainly in the tropics, is expected if aerosol-lighting-ozone link is parameterized, depending on the background emission scenario. We note, however, substantial uncertainties remain on the exact magnitude of aerosol effect on tropospheric O3 via lightning. The challenges for obtaining a quantitative global estimate of this effect are also discussed. Our results have significant implications

Avian Pox in Turkey Vulture (Cathartes aura)

African Journals Online (AJOL)

Campbell Murn

Vulture Cathartes aura meridionalis was captured for wing-tagging on San. Francisco, Zulia state, Venezuela. (10°32'15"N, -71°38'10"W). Nodular cutaneous lesions were observed on the head (Figure 1A). Sections of the skin were removed and fixed in 10% buffer formalin and submitted to. Laboratorio de. Diagnostico.

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

The Ozone Budget in the Upper Troposphere from Global Modeling Initiative (GMI)Simulations

Science.gov (United States)

Rodriquez, J.; Duncan, Bryan N.; Logan, Jennifer A.

2006-01-01

Ozone concentrations in the upper troposphere are influenced by in-situ production, long-range tropospheric transport, and influx of stratospheric ozone, as well as by photochemical removal. Since ozone is an important greenhouse gas in this region, it is particularly important to understand how it will respond to changes in anthropogenic emissions and changes in stratospheric ozone fluxes.. This response will be determined by the relative balance of the different production, loss and transport processes. Ozone concentrations calculated by models will differ depending on the adopted meteorological fields, their chemical scheme, anthropogenic emissions, and treatment of the stratospheric influx. We performed simulations using the chemical-transport model from the Global Modeling Initiative (GMI) with meteorological fields from (It)h e NASA Goddard Institute for Space Studies (GISS) general circulation model (GCM), (2) the atmospheric GCM from NASA's Global Modeling and Assimilation Office(GMAO), and (3) assimilated winds from GMAO . These simulations adopt the same chemical mechanism and emissions, and adopt the Synthetic Ozone (SYNOZ) approach for treating the influx of stratospheric ozone -. In addition, we also performed simulations for a coupled troposphere-stratosphere model with a subset of the same winds. Simulations were done for both 4degx5deg and 2degx2.5deg resolution. Model results are being tested through comparison with a suite of atmospheric observations. In this presentation, we diagnose the ozone budget in the upper troposphere utilizing the suite of GMI simulations, to address the sensitivity of this budget to: a) the different meteorological fields used; b) the adoption of the SYNOZ boundary condition versus inclusion of a full stratosphere; c) model horizontal resolution. Model results are compared to observations to determine biases in particular simulations; by examining these comparisons in conjunction with the derived budgets, we may pinpoint

Multimodel ensemble simulations of present-day and near-future tropospheric ozone

NARCIS (Netherlands)

Stevenson, D.S.; Dentener, F.J.; Schultz, M.G.; Ellingsen, K.; Noije, van T.P.C.; Wild, O.; Zeng, G.; Amann, M.; Atherton, C.S.; Bell, N.; Bergmann, D.J.; Bey, I.; Butler, T.; Cofala, J.; Collins, W.J.; Derwent, R.G.; Doherty, R.M.; Drevet, J.; Eskes, H.J.; Fiore, A.M.; Gauss, M.; Hauglustaine, D.A.; Horowitz, L.W.; Isaksen, I.S.A.; Krol, M.C.; Lamarque, J.F.; Lawrence, M.G.; Montanaro, V.; Muller, J.F.; Pitari, G.; Prather, M.J.; Pyle, J.A.; Rast, S.; Rodriguez, J.M.; Sanderson, M.G.; Savage, N.H.; Shindell, D.T.; Strahan, S.E.; Sudo, K.; Szopa, S.

2006-01-01

Global tropospheric ozone distributions, budgets, and radiative forcings from an ensemble of 26 state-of-the-art atmospheric chemistry models have been intercompared and synthesized as part of a wider study into both the air quality and climate roles of ozone. Results from three 2030 emissions

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.;

Maintaining Aura's Orbit Requirements While Performing Orbit Maintenance Maneuvers Containing an Orbit Normal Delta-V Component

Science.gov (United States)

Johnson, Megan R.; 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 Aura's Mean Local Time (MLT) which drives the required along track separation between Aura and the constellation members, as well as Aura's 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 noslew operations.

Global emissions and models of photochemically active compounds

International Nuclear Information System (INIS)

Penner, J.E.; Atherton, C.S.; Graedel, T.E.

1993-01-01

Anthropogenic emissions from industrial activity, fossil fuel combustion, and biomass burning are now known to be large enough (relative to natural sources) to perturb the chemistry of vast regions of the troposphere. A goal of the IGAC Global Emissions Inventory Activity (GEIA) is to provide authoritative and reliable emissions inventories on a 1 degree x 1 degree grid. When combined with atmospheric photochemical models, these high quality emissions inventories may be used to predict the concentrations of major photochemical products. Comparison of model results with measurements of pertinent species allows us to understand whether there are major shortcomings in our understanding of tropospheric photochemistry, the budgets and transport of trace species, and their effects in the atmosphere. Through this activity, we are building the capability to make confident predictions of the future consequences of anthropogenic emissions. This paper compares IGAC recommended emissions inventories for reactive nitrogen and sulfur dioxide to those that have been in use previously. We also present results from the three-dimensional LLNL atmospheric chemistry model that show how emissions of anthropogenic nitrogen oxides might potentially affect tropospheric ozone and OH concentrations and how emissions of anthropogenic sulfur increase sulfate aerosol loadings

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

Directory of Open Access Journals (Sweden)

H.-D. Choi

2017-07-01

Full Text Available 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

Lower tropospheric ozone over India and its linkage to the South Asian monsoon

Science.gov (United States)

Lu, Xiao; Zhang, Lin; Liu, Xiong; Gao, Meng; Zhao, Yuanhong; Shao, Jingyuan

2018-03-01

Lower tropospheric (surface to 600 hPa) ozone over India poses serious risks to both human health and crops, and potentially affects global ozone distribution through frequent deep convection in tropical regions. Our current understanding of the processes controlling seasonal and long-term variations in lower tropospheric ozone over this region is rather limited due to spatially and temporally sparse observations. Here we present an integrated process analysis of the seasonal cycle, interannual variability, and long-term trends of lower tropospheric ozone over India and its linkage to the South Asian monsoon using the Ozone Monitoring Instrument (OMI) satellite observations for years 2006-2014 interpreted with a global chemical transport model (GEOS-Chem) simulation for 1990-2010. OMI observed lower tropospheric ozone over India averaged for 2006-2010, showing the highest concentrations (54.1 ppbv) in the pre-summer monsoon season (May) and the lowest concentrations (40.5 ppbv) in the summer monsoon season (August). Process analyses in GEOS-Chem show that hot and dry meteorological conditions and active biomass burning together contribute to 5.8 Tg more ozone being produced in the lower troposphere in India in May than January. The onset of the summer monsoon brings ozone-unfavorable meteorological conditions and strong upward transport, which all lead to large decreases in the lower tropospheric ozone burden. Interannually, we find that both OMI and GEOS-Chem indicate strong positive correlations (r = 0.55-0.58) between ozone and surface temperature in pre-summer monsoon seasons, with larger correlations found in high NOx emission regions reflecting NOx-limited production conditions. Summer monsoon seasonal mean ozone levels are strongly controlled by monsoon strengths. Lower ozone concentrations are found in stronger monsoon seasons mainly due to less ozone net chemical production. Furthermore, model simulations over 1990-2010 estimate a mean annual trend of 0

Troc: a proposed tropospheric sounder for chemistry and climate

Science.gov (United States)

Camy-Peyret, C.

TROC has been submitted to ESA in the last call for proposals of the Earth Explorer Opportunity Missions and its focus is on tropospheric composition and chemistry-climate interactions. The mission objectives of TROC cover four research subjects. Global tropospheric chemistry: perform global measurements from space of tropospheric composition in order to improve our understanding and to constrain models of tropospheric chemistry with emphasis on tropospheric ozone. Pollution: establish the impact of mega cities of industrialised or developing countries by monitoring their pollution plumes. Biomass burning: monitor the chemical species and aerosols injected in the free troposphere during major burning episodes in the intertropical region as well as by major forest fires at other latitudes. Chemistry-climate interactions: quantify on a global scale the distributions and the sources of greenhouse gases like CO2, CH4, O3, N2O and the CFCs. Contribute to demonstration studies for monitoring from space how Montreal and Kyoto protocols are enforced as far as human impacts on atmospheric chemistry and climate are concerned. To fulfil these objectives, passive remote sensing of the troposphere has been selected as the best compromise between technical maturity and multi-species coverage. The main elements of TROC are a Fourier transform infrared (FTIR) instrument and an ultraviolet-visible (UV-vis) spectrometer, both operating in the downward-looking geometry with a 10 km diameter footprint at nadir. An ``intelligent'' pointing mirror coupled to an infrared imager is used to optimise day/night sounding down to the surface. The FTIR instrument covers at 0.1 cm-1 apodised spectral resolution 3 bands from 14 to 3.3 μ m in thermal emission and one band in solar reflected light around 2.3 μ m. The UV-vis instrument covers the regions 290-490 nm (1 nm resolution) and 520-1030 nm (2.5 nm resolution) with 43 array detectors (2 bands × 2 polarizations) in reflected

Estimating Western U.S. Oil & Gas Emissions with OMI NO2 Data

Science.gov (United States)

Clifton, O. E.; Holloway, T.; Oberman, J.

2012-12-01

In the last ten years, there has been a steep increase in the number natural gas and oil extraction facilities in the United States due to hydraulic fracturing ("fracking"). Each facility requires a large range of equipment, such as drilling rigs, compressor engines, heaters, and pneumatic devices. These activities can lead to elevated nitrogen dioxide (NO2) emissions in rural areas, often in regions without routine NO2 surface monitoring. Furthermore, permitting rules vary from state to state, and many new extraction facilities are unpermitted and exact emissions unknown. On April 18, 2012, the EPA announced air pollution standards for volatile organic compounds (VOCs) emissions from the oil and gas industry. Until 2015, when these standards must be in effect, NOx (NO2 + NO) will continue to react with VOCs to form unhealthy levels of tropospheric ozone in regions with heavy use of hydraulic fracturing. In order to identify areas of elevated NO2 emissions and constrain associated on-road and off-road sources in areas with prominent shale basins and known drilling, we employ remote sensing estimates of column NO2 from the Ozone Monitoring Instrument (OMI) aboard NASA's Aura satellite. OMI NO2 is sensitive to the planetary boundary layer and to surface air pollution and thus has high temporal and spatial variation. These Level-2 satellite data are processed with the Wisconsin Horizontal Interpolation Program for Satellites (WHIPS), developed at the University of Wisconsin-Madison. We interpolate the data to allow further ease in mapping change in NO2 associated with drilling, and the quantification of pollution trends attributable to hydraulic-fracturing in the Western U.S. from 2004 to the present.

Cross-validation of IASI/MetOp derived tropospheric δD with TES and ground-based FTIR observations

Science.gov (United States)

Lacour, J.-L.; Clarisse, L.; Worden, J.; Schneider, M.; Barthlott, S.; Hase, F.; Risi, C.; Clerbaux, C.; Hurtmans, D.; Coheur, P.-F.

2015-03-01

The Infrared Atmospheric Sounding Interferometer (IASI) flying onboard MetOpA and MetOpB is able to capture fine isotopic variations of the HDO to H2O ratio (δD) in the troposphere. Such observations at the high spatio-temporal resolution of the sounder are of great interest to improve our understanding of the mechanisms controlling humidity in the troposphere. In this study we aim to empirically assess the validity of our error estimation previously evaluated theoretically. To achieve this, we compare IASI δD retrieved profiles with other available profiles of δD, from the TES infrared sounder onboard AURA and from three ground-based FTIR stations produced within the MUSICA project: the NDACC (Network for the Detection of Atmospheric Composition Change) sites Kiruna and Izaña, and the TCCON site Karlsruhe, which in addition to near-infrared TCCON spectra also records mid-infrared spectra. We describe the achievable level of agreement between the different retrievals and show that these theoretical errors are in good agreement with empirical differences. The comparisons are made at different locations from tropical to Arctic latitudes, above sea and above land. Generally IASI and TES are similarly sensitive to δD in the free troposphere which allows one to compare their measurements directly. At tropical latitudes where IASI's sensitivity is lower than that of TES, we show that the agreement improves when taking into account the sensitivity of IASI in the TES retrieval. For the comparison IASI-FTIR only direct comparisons are performed because the sensitivity profiles of the two observing systems do not allow to take into account their differences of sensitivity. We identify a quasi negligible bias in the free troposphere (-3‰) between IASI retrieved δD with the TES, which are bias corrected, but important with the ground-based FTIR reaching -47‰. We also suggest that model-satellite observation comparisons could be optimized with IASI thanks to its high

Auras and clinical features in temporal lobe epilepsy: a new approach on the basis of voxel-based morphometry.

Science.gov (United States)

Santana, Maria Teresa Castilho Garcia; Jackowski, Andrea Parolin; da Silva, Henrique Hattori; Caboclo, Luis Otávio Sales Ferreira; Centeno, Ricardo Silva; Bressan, Rodrigo A; Carrete, Henrique; Yacubian, Elza Márcia Targas

2010-05-01

MRI investigations in patients with temporal lobe epilepsy (TLE) with mesial temporal sclerosis (MTS) have demonstrated structural abnormalities extending beyond ipsilateral hippocampus which may be studied through voxel-based morphometry (VBM). We investigated brain morphology related to clinical features in patients with refractory TLE with MTS using VBM. One hundred patients with unilateral TLE with MTS (59 left) and 30 controls were enrolled. VBM5 was employed to analyze (1) hemispheric damage, (2) influence of initial precipitating injury (IPI): 23 patients with febrile seizures and 19 with status epilepticus, and (3) types of auras classified as: mesial, including psychic auras (19 patients); anterior mesio-lateral, as autonomic symptoms, specially epigastric auras (27 patients) and neocortical, which included auditory, vertiginous, somatosensory and visual auras (16 patients). (1) Left TLE patients presented more widespread gray matter volume (GMV) reductions affecting ipsilateral hippocampus, temporal neocortex, insula and also left uncus, precentral gyrus, thalamus, parietal lobule, cuneus and bilateral cingulum. (2) Febrile seizures group presented ipsilateral GMV reductions in hippocampus, neocortical temporal, frontal and occipital cortices, insula and cingulum. Status epilepticus group presented more widespread GMV reductions involving temporal and extratemporal lobes. (3) Patients with mesial auras showed significant ipsilateral GMV reductions in hippocampus and amygdala, particularly right TLE group, who presented greater extension of GMV reduction in the entorhinal cortex. Significant reductions in hippocampus, amygdala and insula were seen in patients with anterior mesio-lateral auras. This study evaluated a large number of TLE-MTS patients showing structural damage extending beyond hippocampus, and different types of IPI associated with the extension of brain damage. Subtypes of auras are related to different clusters of areas of GMV reductions in

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

MLS/Aura Level 2 Diagnostics, Geophysical Parameter Grid V004

Data.gov (United States)

National Aeronautics and Space Administration — ML2DGG is the EOS Aura Microwave Limb Sounder (MLS) product containing geophysical diagnostic quantities pertaining directly to the standard geophysical data...

Migrainous aura as stroke-mimic: The role of perfusion-computed tomography.

Science.gov (United States)

Ridolfi, Mariana; Granato, Antonio; Polverino, Paola; Furlanis, Giovanni; Ukmar, Maja; Zorzenon, Irene; Manganotti, Paolo

2018-03-01

The acute-onset of migrainuos aura (MA) can be erroneously diagnosed in Emergency Department (ED) as acute stroke (AS) and it can be classified as "stroke mimic" (SM). Perfusion computer tomography (PCT) may be useful to improve detection of infarcts. The aim of the study was to investigate the role in ED of PCT in improving diagnosis of migrainous aura. Data were compared with the well-defined perfusion patterns in patients with acute ischemic stroke. A standardized Stroke Protocol was planned. The protocol consisted in centralizing in ED all the patients with acute-onset of neurological symptoms compatible with cerebrovascular disease and in performing a general and neurological examination, hematological tests, brain non-contrast computed tomography (NCCT), CT angiography (CTA) of the supra-aortic and intracranial arteries and cerebral PCT. Patients with diagnosis of definite or probable acute stroke were hospitalized in Stroke Unit (SU). A six-months retrospective analysis of all the patients included in the Stroke Protocol and discharged from ED or from SU with a diagnosis of migraine with aura was performed. 172 patients were included in the Stroke Protocol and 6 patients were enrolled. NCCT, CTA and PCT were performed after 60-90 min from symptoms onset and revealed normal perfusion. Intravenous thrombolysis was performed only in one patient. Patients with acute-onset of neurological symptoms, who have rapid progressive improvement of symptoms, normal neuroimaging, in particular PCT, and preceding episodes of migraine with aura, may be considered as suffering from MA. In these cases, even if thrombolysis is safe, clinicians may defer a prompt aggressive treatment. Copyright © 2018 Elsevier B.V. All rights reserved.

Why are models unable to reproduce multi-decadal trends in lower tropospheric baseline ozone levels?

Science.gov (United States)

Hu, L.; Liu, J.; Mickley, L. J.; Strahan, S. E.; Steenrod, S.

2017-12-01

Assessments of tropospheric ozone radiative forcing rely on accurate model simulations. Parrish et al (2014) found that three chemistry-climate models (CCMs) overestimate present-day O3 mixing ratios and capture only 50% of the observed O3 increase over the last five decades at 12 baseline sites in the northern mid-latitudes, indicating large uncertainties in our understanding of the ozone trends and their implications for radiative forcing. Here we present comparisons of outputs from two chemical transport models (CTMs) - GEOS-Chem and the Global Modeling Initiative model - with O3 observations from the same sites and from the global ozonesonde network. Both CTMs are driven by reanalysis meteorological data (MERRA or MERRA2) and thus are expected to be different in atmospheric transport processes relative to those freely running CCMs. We test whether recent model developments leading to more active ozone chemistry affect the computed ozone sensitivity to perturbations in emissions. Preliminary results suggest these CTMs can reproduce present-day ozone levels but fail to capture the multi-decadal trend since 1980. Both models yield widespread overpredictions of free tropospheric ozone in the 1980s. Sensitivity studies in GEOS-Chem suggest that the model estimate of natural background ozone is too high. We discuss factors that contribute to the variability and trends of tropospheric ozone over the last 30 years, with a focus on intermodel differences in spatial resolution and in the representation of stratospheric chemistry, stratosphere-troposphere exchange, halogen chemistry, and biogenic VOC emissions and chemistry. We also discuss uncertainty in the historical emission inventories used in models, and how these affect the simulated ozone trends.

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

DEFF Research Database (Denmark)

Tfelt-Hansen, P C

2010-01-01

Several personal descriptions of migraine with aura from 1870 onwards reported a slow, gradual progression of symptoms. Lashley in 1941 meticulously chartered his own auras and concluded that the symptomatology reflected a cortical process progressing with a speed of 3 mm/min across the primary...... for measurements of regional cerebral blood flow (rCBF) in 1974 made it possible to detect spreading oligaemia during migraine aura. Between 1981 and 1990 a series of studies of rCBF during migraine attacks showed reduced brain blood flow posteriorly spreading slowly and contiguously anteriorly and crossing...... and it was considerably strengthened by the demonstration of a long-lasting oligaemia in rats in the wake of CSD. In the primates CSD is not easily elicited, but it has in recent years been clearly demonstrated in patients with brain trauma and stroke. Finally, mutations for familial hemiplegic migraine have been...

Trends of tropospheric NO2 over the Yangtze River Delta region and the possible linkage to rapid urbanization

Science.gov (United States)

Ma, Mingliang; Zhang, Deying; Liu, Qiyang; Song, Yue; Zhou, Jiayuan; Shi, Runhe; Gao, Wei

2017-09-01

Over the past decade, China has experienced a rapid increase in urbanization. The urban built-up areas (population) of Shanghai increased by 16.1% (22.9%) from 2006 to 2015. This study aims to analyze the variations of tropospheric NO2 over Yangtze River Delta region and the impacts of rapid urbanization during 2006-2015. The results indicate that tropospheric NO2 vertical column density (VCD) of all cities in the study area showed an increasing trend during 2006-2011 whereas a decreasing trend during 2011-2015. Most cities showed a lower tropospheric NO2 VCD value in 2015 compared to that in 2006, except for Changzhou and Nantong. Shanghai and Ningbo are two hotspots where the tropospheric NO2 VCD decreased most significantly, at a rate of 22% and 19%, respectively. This effect could be ascribed to the implementation of harsh emission control policies therein. Similar seasonal variability was observed over all cities, with larger values observed in the summer and smaller values shown in the winter. Further investigations show that the observed increasing trend of tropospheric NO2 during 2006-2011 could be largely explained by rapid urbanization linked to car ownership, GDP, power consumption, population and total industrial output. Such effect was not prominent after 2011, mainly due to the implementation of emission control strategies.

Multimodel ensemble simulations of of present-day and near-future tropospheric ozone

NARCIS (Netherlands)

Stevenson, D.S.; Dentener, F.J.; van Noije, T.P.C.; Eskes, H.J.; Krol, M.C.

2006-01-01

Global tropospheric ozone distributions, budgets, and radiative forcings from an ensemble of 26 state-of-the-art atmospheric chemistry models have been intercompared and synthesized as part of a wider study into both the air quality and climate roles of ozone. Results from three 2030 emissions

Trends of rural tropospheric ozone at the northwest of the Iberian Peninsula.

Science.gov (United States)

Saavedra, S; Rodríguez, A; Souto, J A; Casares, J J; Bermúdez, J L; Soto, B

2012-01-01

Tropospheric ozone levels around urban and suburban areas at Europe and North America had increased during 80's-90's, until the application of NO(x) reduction strategies. However, as it was expected, this ozone depletion was not proportional to the emissions reduction. On the other hand, rural ozone levels show different trends, with peaks reduction and average increments; this different evolution could be explained by either emission changes or climate variability in a region. In this work, trends of tropospheric ozone episodes at rural sites in the northwest of the Iberian Peninsula were analyzed and compared to others observed in different regions of the Atlantic European coast. Special interest was focused on the air quality sites characterization, in order to guarantee their rural character in terms of air quality. Both episodic local meteorological and air quality measurements along five years were considered, in order to study possible meteorological influences in ozone levels, different to other European Atlantic regions.

Trends of Rural Tropospheric Ozone at the Northwest of the Iberian Peninsula

Directory of Open Access Journals (Sweden)

S. Saavedra

2012-01-01

Full Text Available Tropospheric ozone levels around urban and suburban areas at Europe and North America had increased during 80’s–90’s, until the application of NOx reduction strategies. However, as it was expected, this ozone depletion was not proportional to the emissions reduction. On the other hand, rural ozone levels show different trends, with peaks reduction and average increments; this different evolution could be explained by either emission changes or climate variability in a region. In this work, trends of tropospheric ozone episodes at rural sites in the northwest of the Iberian Peninsula were analyzed and compared to others observed in different regions of the Atlantic European coast. Special interest was focused on the air quality sites characterization, in order to guarantee their rural character in terms of air quality. Both episodic local meteorological and air quality measurements along five years were considered, in order to study possible meteorological influences in ozone levels, different to other European Atlantic regions.

[Migraine without aura treated with balance acupuncture therapy:a randomized controlled trial].

Science.gov (United States)

Wang, Jinzhong; Qin, Xiaolan; Xie, Wenyuan; Wang, Wenyuan

2017-08-12

To assess the effect of balance acupuncture for migraine without aura. Blind evaluation was conducted. Forty patients with migraine without aura were randomized into an observation group and a control group, 19 cases in each one with 1 patient dropped out respectively. In the observation group, Toutongxue , the middle point was used in the hollow before the 1, 2 metatarsal combination, and in the control group, a sham point was applied in the hollow before the 3, 4 metatarsal combination. The manipulation in the two groups was the same. The treatment was given for 4 weeks, once a day, 5 times a week. The comprehensive score and visual analogue scale (VAS) were used before and after treatment, as well as 4 weeks after treatment. The comprehensive score and VAS score after treatment in the observation group decreased after treatment (both P 0.05). All the indices in the observation group after treatment and at follow-up were lower than those in the control group (all P 0.05). Balance acupuncture at Toutongxue achieves obvious effect for migraine without aura, which can relieve pain.

Tropospheric Ozone Source Attribution in Southern California during Summer 2014 Based on Lidar Measurements and Model Simulations

Science.gov (United States)

Granados Munoz, Maria Jose; Johnson, Matthew S.; Leblanc, Thierry

2016-01-01

In the past decades, significant efforts have been made to increase tropospheric ozone long-term monitoring. A large number of ground-based, airborne and space-borne instruments are currently providing valuable data to contribute to better understand tropospheric ozone budget and variability. Nonetheless, most of these instruments provide in-situ surface and column-integrated data, whereas vertically resolved measurements are still scarce. Besides ozonesondes and aircraft, lidar measurements have proven to be valuable tropospheric ozone profilers. Using the measurements from the tropospheric ozone differential absorption lidar (DIAL) located at the JPL Table Mountain Facility, California, and the GEOS-Chem and GEOS-5 model outputs, the impact of the North American monsoon on tropospheric ozone during summer 2014 is investigated. The influence of the Monsoon lightning-induced NOx will be evaluated against other sources (e.g. local anthropogenic emissions and the stratosphere) using also complementary data such as backward-trajectories analysis, coincident water vapor lidar measurements, and surface ozone in-situ measurements.

Sulfur dioxide emissions from Peruvian copper smelters detected by the ozone monitoring instrument

NARCIS (Netherlands)

Carn, S.A.; Krueger, A.J.; Krotkov, N.A.; Yang, Kai; Levelt, P.F.

2007-01-01

We report the first daily observations of sulfur dioxide (SO2) emissions from copper smelters by a satellite-borne sensor - the Ozone Monitoring Instrument (OMI) on NASA's EOS/Aura spacecraft. Emissions from two Peruvian smelters (La Oroya and Ilo) were detected in up to 80% of OMI overpasses

OMI/Aura Ozone (O3) Profile 1-Orbit L2 Swath 13x48km V003

Data.gov (United States)

National Aeronautics and Space Administration — The OMI/Aura Level-2 Ozone Profile data product OMO3PR (Version 003) is now available ( http://disc.gsfc.nasa.gov/Aura/OMI/omo3pr_v003.shtml ) from the NASA Goddard...

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.

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

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.

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.

Tropospheric chemistry research in the U.S.: 1991-1994

Science.gov (United States)

Penner, Joyce E.; Atherton, Cynthia S.; Dignon, Jane

1995-07-01

The troposphere is chemically complex. Many of the important species in the troposphere are short-lived, with lifetimes less than or of order of a month. Hence, the composition of the troposphere is regionally diverse, leading to regionally diverse chemical processes which control that composition. With the advent of three-dimensional models and regionally-specific estimates of emissions, however, it has become clear that human activity has perturbed the composition of even short-lived species over vast regions of the globe. The list of short-lived species of concern includes the reactive nitrogen oxides, reactive sulfur, ozone, nonmethane hydrocarbons and carbon monoxide. Observations have established that increases in the long-lived species such as carbon dioxide, methane, nitrous oxide, and the chlorofluorocarbons are taking place with important resulting impacts on stratospheric chemistry. Further, there is some indication that carbonyl sulfide (a major precursor to stratospheric aerosols) may have an important anthropogenic source. Growth of pollutants such as these are of concern because they act as greenhouse gases or aerosol precursors (CO2, CH4, O3, N2O, chlorofluorocarbons, carbonyl sufide, reactive sulfur), as agents for depletion of stratospheric ozone (N2O, chlorofluorocarbons), are harmful to vegetation (O3, acids) or act as nutrients (nitrate, sulfate, trace metals). The chemical interactions are important to understand, because the build up of pollutants depends not only on the rates of their release into the troposphere but on their rate of removal in the troposphere. Removal rates depend on processes which determine the rate of oxidation of the component (which for most species proceeds mainly by reaction with the hydroxyl radical) or through precipitation scavenging or dissolution in the ocean (which requires that the pollutant or its oxidation product(s) be soluble in water).

[Migraine with aura and patent foramen ovale. A different clinical entity].

Science.gov (United States)

Ramírez-Moreno, J M; Casado-Naranjo, I; Gómez, M; Portilla, Jc; Caballero, M; Serrano, A; Ojalvo, M J; Falcón, A; Tena-Mora, D; Calle, M

2008-10-01

This work has aimed to evaluate the prevalence of patent foramen ovale in subjects with migraine with aura by transcranial contrast doppler and to describe the clinical and risk profile of these patients. We performed a transcranial contrast doppler in 94 consecutive out-patients with migraine with aura (MWA) in a neurology outpatient clinic. They were divided into two groups according to the presence of patent foramen ovale: MWA_RLsh (with right-to-left shunt) and MWA_RLNsh (without right-to-left shunt). Differences between the groups were analyzed according to endpoints of age, gender, clinical severity, aura type and attacks frequency, comorbility, cardiovascular risk factors (CVRFs), neuroimaging findings, severity of shunt and treatment. n=94; MWA_RLsh: 47 (54%). MWA_RLNsh: 40 (46%). Age: 33.13; standard desviation (SD): 10.8 vs 33.496; SD: 11.2; p=0.728. Female: 66 vs 72.5%; p=0.511. Visual aura: 73.9% vs 78.9%; p=0.921. There were no significant differences in regards to the risk factors studied or to the comorbid diseases that are associated to migraine. The patients with patent foramen ovale have an odds ratio (OR) of ischemic stroke: 1.189 (95% confidence interval [CI]: 0.226 to 6.248; p=0.840), OR for subclinical brain lesions in cranial magnetic resonance imaging (MRI): 0.589 (95% CI: 0.193 to 1.799; p=0.35) and OR for combined previous ischemic stroke and subclinical brain lesions: 0.745 (95% CI: 0.261 to 2.129; p=0.58). Migraine attack frequency >1 per month: 27.9 vs 36.4; p=0.464. Need for prophylaxis therapy: 44.7 vs 57.7%; p=0.284. Both groups are similar regarding their clinical profile. We did not find a greater prevalence of stroke or silent brain lesions in the group with positive shunt..

Site Protection Efforts at the AURA Observatory in Chile

Science.gov (United States)

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

2015-08-01

The AURA Observatory (AURA-O) was the first of the major international observatories to be established in northern Chile to exploit the optimal astronomical conditions available there. The site was originally established in 1962 to host the Cerro Tololo Inter-American Observatory (CTIO). It now hosts more than 20 operational telescopes, including some of the leading U.S. and international astronomical facilities in the southern hemisphere, such as the Blanco 4m telescope on Cerro Tololo and the Gemini-South and SOAR telescopes on Cerro Pachón. Construction of the next generation facility, the Large Synoptic Survey Telescope (LSST), has recently begun on Cerro Pachón, while additional smaller telescopes continue to be added to the complement on Cerro Tololo.While the site has become a major platform for international astronomical facilities over the last 50 years, development in the region has led to an ever-increasing threat of light pollution around the site. AURA-O has worked closely with local, regional, and national authorities and institutions (in particular with the Chilean Ministries of Environment and Foreign Relations) in an effort to protect the site so that future generations of telescopes, as well as future generations of Chileans, can benefit from the dark skies in the region. We will summarize our efforts over the past 15 years to highlight the importance of dark sky 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.

Aura fractal, fins da arte e capitalismo primitivista

Directory of Open Access Journals (Sweden)

Leonardo Carvalho Bertolossi

2017-10-01

Full Text Available Objetiva-se refletir sobre as relações entre as artes visuais e a antropologia a partir do texto seminal de Walter Benjamin sobre a aura para pensar sobre as finalidades e os fins da metafísica da arte no Ocidente diante dos diagnósticos de fim de mundo/fim da história da arte, e da vitória do espetáculo e da indústria cultural no capitalismo contemporâneo. O artigo apresenta alguns dos sentidos da arte no mundo ocidental e em especial no romantismo, avança sobre a crise e o fim dos modelos estruturais e cognitivos do pensamento artístico moderno, destaca o interesse pela política e pela vida, e se indaga sobre a retomada do primitivismo nas artes visuais e na antropologia contemporânea como redenção e renovação das mortes anunciadas. ABSTRACT The objective is to reflect on the relations between the visual arts and anthropology from Walter Benjamin's seminal text on the aura to think about the purposes and ends of the metaphysics of art in the West in the face of end-of-world/end-of-art history, and the victory of spectacle and cultural industry in contemporary capitalism. The article presents some of the meanings of art in the Western world and especially in Romanticism, advances on the crisis and the end of the structural and cognitive models of modern artistic thought, highlights the interest in politics and life, and inquires about the resumption of Primitivism in the visual arts and contemporary anthropology as redemption and renewal of the announced deaths. KEYWORDS Anthropology of art, aura, soul, thanatology, primitivism

MLS/Aura L2 Hydroxyl (OH) Mixing Ratio V002

Data.gov (United States)

National Aeronautics and Space Administration — ML2OH is the EOS Aura Microwave Limb Sounder (MLS) standard product for hydroxyl derived from radiances measured by the THz radiometer. The current version is 2.2....

Ozone and the oxidizing properties of the troposphere

International Nuclear Information System (INIS)

Megie, G.

1996-01-01

This article is about the rising concentration of ozone and photo-oxidizers observed in the troposphere, the atmosphere between the ground and a height of 10 to 15 km. This serious global environmental problem has up to now been less well known than the greenhouse effect or the decrease in stratospheric ozone. This is because it varies with time and place and involves many complicated physico-chemical and atmospheric processes. At our latitudes, the average ozone concentration in the air we breathe has quadrupled since the beginning of this century. In polluted areas it often exceeds the recommended norms. This increase in ozone concentrations in the lower atmosphere directly reflects the impact of man-made emissions of compounds like methane, carbon monoxide, hydrocarbons and nitrogen oxides. Sunlight acts on these compounds to form ozone via complicated chemical reactions. This change in oxidizing properties of the troposphere is beginning produce perceptible effects on vegetable production, human health and climate. (author). 24 refs., 5 figs., 4 tabs

Air Quality Measurements from Satellites during the 2008 Beijing Olympics and Paralympics

Science.gov (United States)

Witte, J. C.; Schoeberl, M.; Douglass, A.; Gleason, J.; Krotkov, N.; Gille, J.; Pickering, K.; Livesey, N.

2009-05-01

In preparation for the Olympic and Paralympic games in August and September 2008 in Beijing, China, the Chinese government imposed strict controls on industrial emissions and motor vehicle traffic in and around the city and vicinity before and during the events to improve the air quality for the competitors and visitors. To test the efficacy of these measures, we used satellite data from NASA's Aura/Ozone Monitoring Instrument (OMI) and Terra/Measurements Of Pollution In The Troposphere (MOPITT) over Beijing and surrounding areas during the Olympic and Paralympic period. The satellite instruments recorded significant reductions in nitrogen dioxide of up to 50%, up to 10% in tropospheric column ozone, 20-40% in boundary layer sulfur dioxide, and 10-20% reductions in carbon monoxide concentrations below 700 hPa.

Application of OMI tropospheric NO2 for air quality monitoring in Northern Europe: shipping and land-based case studies

Science.gov (United States)

Ialongo, Iolanda; Hakkarainen, Janne; Jalkanen, Jukka-Pekka; Johansson, Lasse; Boersma, Folkert; Krotkov, Nickolay; Tamminen, Johanna

2014-05-01

Satellite-based data are very important for air quality applications in the Baltic Sea area, because they provide information on air pollution over sea and there where ground-based network and aircraft measurements are not available. Both the emissions from urban sites over land and ships over sea, contribute to the tropospheric NO2 levels. The tropospheric NO2 monitoring at high latitudes using satellite data is challenging because of the reduced light hours in winter and the snow-covered surface, which make the retrieval complex, and because of the reduced signal due to low Sun. This work presents a detailed characterization of the tropospheric NO2 columns focused on part of the Baltic Sea region using the Ozone Monitoring Instrument (OMI) tropospheric NO2 standard product. Previous works have focused on larger seas and lower latitudes. The results showed that, despite the regional area of interest, it is possible to distinguish the signal from the main coastal cities and from the ships by averaging the data over a seasonal time range. The summertime NO2 emission and lifetime values (E = (1.0 ± 0.1)x1028 molec. and τ = (3.0 ± 0.5) h, respectively) in Helsinki were estimated from the decay of the signal with distance from the city center. The method developed for megacities was successfully applied to a smaller scale source, in both size and intensity (i.e., the city of Helsinki), which is located at high latitudes (~ 60oN). The same methodology could be applied to similar scale cities elsewhere, as far as they are relatively isolated from other sources. The transport by the wind plays an important role in the Baltic Sea area. The NO2 spatial distribution is mainly determined by the contribution of strong westerly winds, which dominate the wind patterns during summer. The comparison between the emissions from model calculations and OMI NO2 tropospheric columns confirmed the applicability of satellite data for ship emission monitoring. In particular, both the

Spectropolarimetric Measurements of Scattered Sunlight in the Huggins Bands: Retrieval of Tropospheric Ozone Profiles

Science.gov (United States)

Fu, D.; Sander, S. P.; Stutz, J.; Pongetti, T. J.; Yung, Y. L.; Wong, M.; Natraj, V.; Li, K.; Shia, R.

2009-12-01

Ozone concentrations in the troposphere have increased over the past century as a result of anthropogenic emissions of NOx and volatile organic compounds. In addition to being harmful to human health and plant life, ozone is an important greenhouse gas, especially in the middle and upper troposphere. Therefore, accurate monitoring of tropospheric ozone vertical distributions is crucial for a better understanding of air quality and climate change. Simulations of vector radiative transfer in the near ultraviolet region have shown that tropospheric ozone profiles can be retrieved using polarization measurements. However, to date there has been no experimental test of this method. A new compact, portable spectropolarimeter has been built for atmospheric remote sensing. The first comprehensive description of the configuration and performance of this instrument for ground-based operation is provided and sample atmospheric scattered sunlight spectra are shown. Using optimal estimation retrieval theory we study the information content of polarization spectra in the Huggins band and uncertainties in the retrieval associated with the measurement parameters, such as aerosol scattering.

Tropospheric ozone over Equatorial Africa: regional aspects from the MOZAIC data

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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.

OMI/Aura Ozone (O3) Total Column 1-Orbit L2 Swath 13x24 km V003

Data.gov (United States)

National Aeronautics and Space Administration — The OMI/Aura Level-2 Total Column Ozone Data Product OMTO3 (Version 003) is made available (http://disc.gsfc.nasa.gov/Aura/OMI/omto3_v003.shtml) from the NASA...

AURA-A radio frequency extension to IceCube

International Nuclear Information System (INIS)

Landsman, H.; Ruckman, L.; Varner, G.S.

2009-01-01

The excellent radio frequency (RF) 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 [A. Karle, Nucl. Instr. and Meth. A (2009), this issue, doi: (10.1016/j.nima.2009.03.180).; A. Achtenberg et al., The IceCube Collaboration, Astropart. Phys. 26 (2006) 155 ] drilling through 2010 to establish the RF technology needed to achieve 100-1000km 3 effective volumes. In the 2006-2007 Austral summer, three deep in-ice RF clusters were deployed at depths of ∼1300 and ∼300m on top of the IceCube strings. Additional three 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 3 sr) radio and acoustic arrays would extend the physics reach of IceCube into the EeV-ZeV regime and offer substantial technological redundancy.

Increased brainstem perfusion, but no blood-brain barrier disruption, during attacks of migraine with aura

DEFF Research Database (Denmark)

Hougaard, Anders; Amin, Faisal M; Christensen, Casper E

2017-01-01

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......-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...

[Cryptogenic stroke - patent foramen ovale - migraine with aura: incidental triad or significant relationship? Part II].

Science.gov (United States)

Łukasik, Maria; Kozubski, Wojciech

2012-01-01

In the second part of the paper, we discuss the relationship between migraine with aura and either patent foramen ovale (PFO) or stroke. The results of the studies suggest that PFO with right-to-left shunt is more prevalent among patients suffering from migraine with aura. Moreover, migraine with aura is a risk factor for ischaemic stroke in women and the risk increases when they have additional vascular risk factors such as taking oral contraception and smoking. However, the pathophysiology of these phenomena remains hypothetical. The most frequently reported theory suggests paradoxical embolism as a mechanism of the above-mentioned pathologies. In this paper we compare the pros and cons of the general theories. We discuss the percutaneous closure of PFO in patients with migraine, regarding the benefit/risk ratio.

Photochemistry and transport of tropospheric ozone and its precursors in urban and remote environments

Science.gov (United States)

Anderson, Daniel Craig

Tropospheric ozone (O3) adversely affects human health, reduces crop yields, and contributes to climate forcing. To limit these effects, the processes controlling O3 abundance as well as that of its precursor molecules must be fully characterized. Here, I examine three facets of O 3 production, both in heavily polluted and remote environments. First, using in situ observations from the DISCOVER-AQ field campaign in the Baltimore/Washington region, I evaluate the emissions of the O 3 precursors CO and NOx (NOx = NO + NO2) in the National Emissions Inventory (NEI). I find that CO/NOx emissions ratios derived from observations are 21% higher than those predicted by the NEI. Comparisons to output from the CMAQ model suggest that CO in the NEI is accurate within 15 +/- 11%, while NOx emissions are overestimated by 51-70%, likely due to errors in mobile sources. These results imply that ambient ozone concentrations will respond more efficiently to NOx controls than current models suggest. I then investigate the source of high O3 and low H2O structures in the Tropical Western Pacific (TWP). A combination of in situ observations, satellite data, and models show that the high O3 results from photochemical production in biomass burning plumes from fires in tropical Southeast Asia and Central Africa; the low relative humidity results from large-scale descent in the tropics. Because these structures have frequently been attributed to mid-latitude pollution, biomass burning in the tropics likely contributes more to the radiative forcing of climate than previously believed. Finally, I evaluate the processes controlling formaldehyde (HCHO) in the TWP. Convective transport of near surface HCHO leads to a 33% increase in upper tropospheric HCHO mixing ratios; convection also likely increases upper tropospheric CH 3OOH to ~230 pptv, enough to maintain background HCHO at ~75 pptv. The long-range transport of polluted air, with NO four times the convectively controlled background

Study of stratosphere-troposphere exchange via 10Be/7Be isotope ratios

International Nuclear Information System (INIS)

Priller, A.; Berger, M.; Golser, R.; Kutschera, W.; Steier, P.; Vockenhuber, C.; Wild, E.M.

2001-01-01

Full text: The present study is part of the European project STACCATO (influence of stratosphere-troposphere exchange in a changing climate on atmospheric transport and oxidation capacity). Stratosphere-troposphere exchange (STE) is one of the key factors controlling the budgets of ozone, water vapor and other substances in both the troposphere and the lower stratosphere. However, its contribution to their ozone budget relative to photo-chemical ozone formation from natural and anthropogenic precursor emissions is still uncertain. An international effort is made to estimate the strength of STE and its impact on tropospheric chemistry. The two cosmogenic radioisotopes of beryllium, 10 Be and 7 Be have very different half-lives of 1.51 Ma and 53.4 d, respectively. The combination of production rates, half-lives and different residence times in the stratosphere and troposphere, respectively, results in 10 Be/ 7 Be isotope ratios which can be used as fingerprints for STE. This ratio helps to give a much improved estimate of STE. However, only few 10 Be measurements exist, because its detection requires the rather elaborate method of accelerator mass spectrometry (AMS). At the AMS facility VERA we are now measuring the 10 Be content of air filters from the high-alpine stations 'Hoher Sonnblick', Austria, and 'Zugspitze', Germany. The TBe content is measured separately by decay counting. In this presentation, we want to describe the method of measuring 10 Be with AMS, and to discuss the results of first 10 Be/ 7 Be ratios. (author)

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

Aerosol indirect effects on lightning in the generation of induced NOx and tropospheric ozone over an Indian urban metropolis

Science.gov (United States)

Saha, Upal; Maitra, Animesh; Talukdar, Shamitaksha; Jana, Soumyajyoti

Lightning flashes, associated with vigorous convective activity, is one of the most prominent weather phenomena in the tropical atmosphere. High aerosol loading is indirectly associated with the increase in lightning flash rates via the formation of tropospheric ozone during the pre-monsoon and monsoon over the tropics. Tropospheric ozone, an important greenhouse pollutant gas have impact on Earth’s radiation budget and play a key role in changing the atmospheric circulation patterns. Lightning-induced NOx is a primary pollutant found in photochemical smog and an important precursor for the formation of tropospheric ozone. A critical analysis is done to study the indirect effects of high aerosol loading on the formation of tropospheric ozone via lightning flashes and induced NOx formation over an urban metropolitan location Kolkata (22°32'N, 88°20'E), India during the period 2001-2012. The seasonal variation of lightning flash rates (LFR), taken from TRMM-LIS 2.5o x 2.5o gridded dataset, show that the LFR was observed to be intensified in the pre-monsoon (March-May) and high in monsoon (June-September) months over the region. Aerosol Optical Depth (AOD) at 555nm, taken from MISR 0.5o x 0.5o gridded level-3 dataset, plays an indirect effect on the increase in LFR during the pre-monsoon and monsoon months and has positive correlations between them during these periods. This is also justified from the seasonal variation of the increase in LFR due to the increase in AOD over the region during 2001-2012. The calibrated GOME and OMI/AURA satellite data analysis shows that the tropospheric ozone, formed as a result of lightning-induced NOx and due to the increased AOD at 555 nm, also increases during the pre-monsoon and monsoon months. The seasonal variation of lightning-induced tropospheric NOx, taken from SCIAMACHY observations also justified the fact that the pre-monsoon and monsoon LFR solely responsible for the generation of induced NOx over the region. The

OMI/Aura DOAS Total Column Ozone Zoomed 1-Orbit L2 Swath 13x12km V003

Data.gov (United States)

National Aeronautics and Space Administration — The reprocessed OMI/Aura Level-2 Zoomed Ozone data product OMDOAO3Z at 13x12 km resolution is now available (http://disc.gsfc.nasa.gov/Aura/OMI/omdoao3z_v003.shtml )...

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...... repeatedly. Headache was induced in all migraine patients and in eight of 10 healthy subjects (P = 0.47) with no significant difference in headache intensity (P = 0.53). However, five patients but only one healthy subject experienced the symptoms of migraine without aura, according to ICHD-2 criteria, within....... Thus, dipyridamole induces symptoms of migraine and an initial decrease in V(mca) in migraine patients, but not significantly more than in healthy subjects. This relatively low frequency of migraine induction, compared with nitric oxide donors and sildenafil, is probably due to the less specific action...

Hearing voices: does it give your patient a headache? A case of auditory hallucinations as acoustic aura in migraine

Directory of Open Access Journals (Sweden)

Van der Feltz-Cornelis CM

2012-03-01

Full Text Available Christina M van der Feltz-Cornelis1–3, Henk Biemans1, Jan Timmer11Clinical Centre for Body, Mind and Health, GGz Breburg, Tilburg, The Netherlands; 2Faculty of Social and Behavioral Sciences, Tilburg University, Tilburg, The Netherlands; 3Trimbos Instituut, Utrecht, The NetherlandsObjective: Auditory hallucinations are generally considered to be a psychotic symptom. However, they do occur without other psychotic symptoms in a substantive number of cases in the general population and can cause a lot of individual distress because of the supposed association with schizophrenia. We describe a case of nonpsychotic auditory hallucinations occurring in the context of migraine.Method: Case report and literature review.Results: A 40-year-old man presented with imperative auditory hallucinations that caused depressive and anxiety symptoms. He reported migraine with visual aura as well which started at the same time as the auditory hallucinations. The auditory hallucinations occurred in the context of nocturnal migraine attacks, preceding them as aura. No psychotic disorder was present. After treatment of the migraine with propranolol 40 mg twice daily, explanation of the etiology of the hallucinations, and mirtazapine 45 mg daily, the migraine subsided and no further hallucinations occurred. The patient recovered.Discussion: Visual auras have been described in migraine and occur quite often. Auditory hallucinations as aura in migraine have been described in children without psychosis, but this is the first case describing auditory hallucinations without psychosis as aura in migraine in an adult. For description of this kind of hallucination, DSM-IV lacks an appropriate category.Conclusion: Psychiatrists should consider migraine with acoustic aura as a possible etiological factor in patients without further psychotic symptoms presenting with auditory hallucinations, and they should ask for headache symptoms when they take the history. Prognosis may be

Field-testing of the ICHD-3 beta/proposed ICD-11 diagnostic criteria for migraine with aura

DEFF Research Database (Denmark)

Li, Dana; Christensen, Anne F; Olesen, Jes

2015-01-01

migraine (SHM) and 1.2.6 basilar-type migraine according to ICHD-2 in a cross-sectional study design. A database of 2464 patients with 1.1 migraine without aura and 1.2 migraine with non-hemiplegic aura and a database of 252 hemiplegic migraine patients (1.2.4 FHM or 1.2.5 SHM) was collected. We used SPSS...

Increased intrinsic brain connectivity between pons and somatosensory cortex during attacks of migraine with aura

DEFF Research Database (Denmark)

Hougaard, Anders; Amin, Faisal Mohammad; Larsson, Henrik B W

2017-01-01

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......-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......-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...

Executive dysfunctions in migraine with and without aura: what is the role of white matter lesions?

Science.gov (United States)

Le Pira, Francesco; Reggio, Ester; Quattrocchi, Graziella; Sanfilippo, Cristina; Maci, Tiziana; Cavallaro, Tiziana; Zappia, Mario

2014-01-01

Executive dysfunctions and white matter lesions on magnetic resonance imaging have been reported in migraine. The aim of this study was to determine whether any correlation between these 2 variables exists. Forty-four subjects affected by migraine with or without aura were compared with 16 healthy subjects. A battery of neuropsychological tests assessing executive functions was administered to all subjects. Number and total volume of white matter lesions were assessed in the whole brain and in the frontal lobe. The performances of both groups of migraineurs, with and without aura, were significantly worse when compared with controls on Boston Scanning Test. Moreover, we found lower performances compared with controls respectively on Frontal Assessment Battery in patients with migraine with aura and on Controlled Oral Word Association Test in patients with migraine without aura. Nineteen patients (43.2%) and one control subject (6.2%) had white matter lesions. We did not find any significant correlation between white matter lesions load and neuropsychological performances. On the basis of our results, white matter lesions load on magnetic resonance imaging do not seem to contribute to neuropsychological performances deficit in migraineurs. © 2013 American Headache Society.

Ship-based MAX-DOAS measurements of tropospheric NO2, SO2, and HCHO distribution along the Yangtze River

Science.gov (United States)

Hong, Qianqian; Liu, Cheng; Chan, Ka Lok; Hu, Qihou; Xie, Zhouqing; Liu, Haoran; Si, Fuqi; Liu, Jianguo

2018-04-01

In this paper, we present ship-based Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements of tropospheric trace gases' distribution along the Yangtze River during winter 2015. The measurements were performed along the Yangtze River between Shanghai and Wuhan, covering major industrial areas in eastern China. Tropospheric vertical column densities (VCDs) of nitrogen dioxide (NO2), sulfur dioxide (SO2), and formaldehyde (HCHO) were retrieved using the air mass factor calculated by the radiative transfer model. Enhanced tropospheric NO2 and SO2 VCDs were detected over downwind areas of industrial zones over the Yangtze River. In addition, spatial distributions of atmospheric pollutants are strongly affected by meteorological conditions; i.e., positive correlations were found between concentration of pollutants and wind speed over these areas, indicating strong influence of transportation of pollutants from high-emission upwind areas along the Yangtze River. Comparison of tropospheric NO2 VCDs between ship-based MAX-DOAS and Ozone Monitoring Instrument (OMI) satellite observations shows good agreement with each other, with a Pearson correlation coefficient (R) of 0.82. In this study, the NO2 / SO2 ratio was used to estimate the relative contributions of industrial sources and vehicle emissions to ambient NO2 levels. Analysis results of the NO2 / SO2 ratio show a higher contribution of industrial NO2 emissions in Jiangsu Province, while NO2 levels in Jiangxi and Hubei provinces are mainly related to vehicle emissions. These results indicate that different pollution control strategies should be applied in different provinces. In addition, multiple linear regression analysis of ambient carbon monoxide (CO) and odd oxygen (Ox) indicated that the primary emission and secondary formation of HCHO contribute 54.4 ± 3.7 % and 39.3 ± 4.3 % to the ambient HCHO, respectively. The largest contribution from primary emissions in winter suggested that

MLS/Aura L2 Hydrogen Chloride (HCl) Mixing Ratio V003

Data.gov (United States)

National Aeronautics and Space Administration — ML2HCL is the EOS Aura Microwave Limb Sounder (MLS) standard product for hydrogen chloride derived from radiances measured primarily by the 640 GHz radiometer. The...

MLS/Aura L2 Hydrogen Cyanide (HCN) Mixing Ratio V003

Data.gov (United States)

National Aeronautics and Space Administration — ML2HCN is the EOS Aura Microwave Limb Sounder (MLS) standard product for hydrogen cyanide derived from radiances measured primarily by the 190 GHz radiometer. The...

MLS/Aura L2 Hydrogen Cyanide (HCN) Mixing Ratio V002

Data.gov (United States)

National Aeronautics and Space Administration — ML2HCN is the EOS Aura Microwave Limb Sounder (MLS) standard product for hydrogen cyanide derived from radiances measured primarily by the 190 GHz radiometer. The...

MLS/Aura Level 2 Hydrogen Chloride (HCl) Mixing Ratio V004

Data.gov (United States)

National Aeronautics and Space Administration — ML2HCL is the EOS Aura Microwave Limb Sounder (MLS) standard product for hydrogen chloride derived from radiances measured primarily by the 640 GHz radiometer. The...

MLS/Aura L2 Hypochlorous Acid (HOCL) Mixing Ratio V003

Data.gov (United States)

National Aeronautics and Space Administration — ML2HOCL is the EOS Aura Microwave Limb Sounder (MLS) standard product for hypochlorous acid derived from radiances measured primarily by the 640 GHz radiometer. The...

MLS/Aura Level 2 Hypochlorous Acid (HOCl) Mixing Ratio V004

Data.gov (United States)

National Aeronautics and Space Administration — ML2HOCL is the EOS Aura Microwave Limb Sounder (MLS) standard product for hypochlorous acid derived from radiances measured primarily by the 640 GHz radiometer. The...

MLS/Aura L2 Hypochlorous Acid (HOCL) Mixing Ratio V002

Data.gov (United States)

National Aeronautics and Space Administration — ML2HOCL is the EOS Aura Microwave Limb Sounder (MLS) standard product for hypochlorous acid derived from radiances measured primarily by the 640 GHz radiometer. The...

Exploring the visual hallucinations of migraine aura: the tacit contribution of illustration.

Science.gov (United States)

Schott, G D

2007-06-01

The visual aura of migraine is a subjective phenomenon, and what the migraineur experiences is necessarily inaccessible to others. Fortunately, however, the sufferer can occasionally reveal what is being seen by means of graphic representation, enabling an otherwise closed 'window' to be opened on the transiently dysfunctioning brain. This article explores the unique contribution that illustration has made to understanding mechanisms subserving the visual aura. The most revealing illustrations are those made by the very few scientists who have recorded and analysed the scotomas, and in particular the expanding fortification spectra, experienced during their migraine attacks. It is solely through illustrations such as these that the uniform nature of many of these hallucinations has been demonstrated. As a result, it follows that there is likely to be a similarly uniform repertoire of processes that generate the hallucinations in the occipital cortex. The precise form of the zigzags that comprise the fortification spectrum, their shimmering appearance, and in particular the speed of the peripheral spread, all of which are entirely dependent on graphic display for their elucidation, enable conclusions to be reached about a number of the underlying pathophysiological mechanisms, including the involvement of spreading cortical depression, that likely occur. Illustration has been pivotal too in revealing uncommon and sometimes curious, if not bizarre, visual hallucinations, the forms of which suggest that extrastriate and temporal lobe involvement contributes to migraine aura in some instances. Illustration can also be valuable in differential diagnosis, depicting other forms of visual hallucination which result from a variety of non-migrainous causes. Illustration, particularly when made during the attack, provides an unusual, little used but powerful tool which uniquely allows the sufferer's subjective visual experiences to inform objective analysis. In turn, this

Reactive Nitrogen, Ozone and Ozone Production in the Arctic Troposphere and the Impact of Stratosphere-Troposphere Exchange

Science.gov (United States)

Liang, Q.; Rodriquez, J. M.; Douglass, A. R.; Crawford, J. H.; Apel, E.; Bian, H.; Blake, D. R.; Brune, W.; Chin, M.; Colarco, P. R.;

A large impact of tropical biomass burning on CO and CO{sub 2} in the upper troposphere

Energy Technology Data Exchange (ETDEWEB)

Hidekazu Matsueda; Shoichi Taguchi; Hisayuki Y; Inoue & Masao Ishii [Meteorological Research Institute, Tsukuba-shi (Japan). Geochemical Research Department

2002-07-01

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 CO{sub 2} cycle largely changed during the 1997 El Nio 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.

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...... of MMP-3 in the external jugular (P = 0.002) and cubital (P = 0.008) vein during attacks compared with outside of attacks. We found no correlation of ictal or interictal MMP-3, MMP-9 and TIMP-1 to migraine duration and frequency analysed in 21 patients (P > 0.05). There was no difference between ictal...

Chemical and climatic drivers of radiative forcing due to changes in stratospheric and tropospheric ozone over the 21st century

Science.gov (United States)

Banerjee, Antara; Maycock, Amanda C.; Pyle, John A.

2018-02-01

The ozone radiative forcings (RFs) resulting from projected changes in climate, ozone-depleting substances (ODSs), non-methane ozone precursor emissions and methane between the years 2000 and 2100 are calculated using simulations from the UM-UKCA chemistry-climate model (UK Met Office's Unified Model containing the United Kingdom Chemistry and Aerosols sub-model). Projected measures to improve air-quality through reductions in non-methane tropospheric ozone precursor emissions present a co-benefit for climate, with a net global mean ozone RF of -0.09 W m-2. This is opposed by a positive ozone RF of 0.05 W m-2 due to future decreases in ODSs, which is driven by an increase in tropospheric ozone through stratosphere-to-troposphere transport of air containing higher ozone amounts. An increase in methane abundance by more than a factor of 2 (as projected by the RCP8.5 scenario) is found to drive an ozone RF of 0.18 W m-2, which would greatly outweigh the climate benefits of non-methane tropospheric ozone precursor reductions. A small fraction (˜ 15 %) of the ozone RF due to the projected increase in methane results from increases in stratospheric ozone. The sign of the ozone RF due to future changes in climate (including the radiative effects of greenhouse gases, sea surface temperatures and sea ice changes) is shown to be dependent on the greenhouse gas emissions pathway, with a positive RF (0.05 W m-2) for RCP4.5 and a negative RF (-0.07 W m-2) for the RCP8.5 scenario. This dependence arises mainly from differences in the contribution to RF from stratospheric ozone changes. Considering the increases in tropopause height under climate change causes only small differences (≤ |0.02| W m-2) for the stratospheric, tropospheric and whole-atmosphere RFs.

OMI/Aura Ozone (O3) Total Column Daily L2 Global 0.25 deg Lat/Lon Grid V003

Data.gov (United States)

National Aeronautics and Space Administration — The OMI/Aura Level-2G Total Column Ozone Data Product OMTO3G (Version 003) is made available ( http://disc.gsfc.nasa.gov/Aura/OMI/omto3g_v003.shtml ) from the NASA...

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.

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...

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 cognitive examination score, although Non-HCD subgroup achieved better score (93.13 ± 3.91 vs 94.29 ± 3.30; t = 1.053, p = 0.298). Findings have shown that migraineurs get lower ACE-R test scores, with a tendency to have a poorer outcome in more complex 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.

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.

Representativeness of the IAGOS airborne measurements in the lower troposphere

Directory of Open Access Journals (Sweden)

H. Petetin

2018-03-01

Full Text Available In the framework of the In Service Aircraft for Global Observing System (IAGOS program, airborne in-situ O3 and CO measurements are performed routinely using in-service aircraft, providing vertical profiles from the surface to about 10–12 km. Due to the specificity of IAGOS measurements (measurements around busy international airports, uncertainties exist on their representativeness in the lower troposphere as they may be impacted by emissions related to airport activities and/or other aircraft. In this study, we thus investigate how the IAGOS measurements in the lower troposphere compare with nearby surface stations (from the local Air Quality monitoring network (AQN and more distant regional surface stations (from the Global Atmospheric Watch (GAW network. The study focuses on Frankfurt but some results at other European airports (Vienna, Paris are also discussed. Results indicate that the IAGOS observations close to the surface do not appear to be strongly impacted by local emissions related to airport activities. In terms of mixing ratio distribution, seasonal variations and trends, the CO and O3 mixing ratios measured by IAGOS in the first few hundred metres above the surface have similar characteristics to the mixing ratios measured at surrounding urban background stations. Higher in altitude, both the difference with data from the local AQN and the consistency with the GAW regional stations are higher, which indicates a larger representativeness of the IAGOS data. Despite few quantitative differences with Frankfurt, consistent results are obtained in the two other cities Vienna and Paris. Based on 11 years of data (2002–2012, this study thus demonstrates that IAGOS observations in the lowest troposphere can be used as a complement to surface stations to study the air quality in/around the agglomeration, providing important information on the vertical distribution of pollution.

TES/Aura L3 H2O Monthly Gridded V004

Data.gov (United States)

National Aeronautics and Space Administration — The TES Aura L3 H2O data consist of daily atmospheric temperature and VMR for the atmospheric species. Data are provided at 2 degree latitude X 4 degree longitude...

Effect of tropical cyclones on the stratosphere–troposphere exchange observed using satellite observations over the north Indian Ocean

Directory of Open Access Journals (Sweden)

M. Venkat Ratnam

2016-07-01

Full Text Available Tropical cyclones play an important role in modifying the tropopause structure and dynamics as well as stratosphere–troposphere exchange (STE processes in the upper troposphere and lower stratosphere (UTLS region. In the present study, the impact of cyclones that occurred over the north Indian Ocean during 2007–2013 on the STE processes is quantified using satellite observations. Tropopause characteristics during cyclones are obtained from the Global Positioning System (GPS radio occultation (RO measurements, and ozone and water vapour concentrations in the UTLS region are obtained from Aura Microwave Limb Sounder (MLS satellite observations. The effect of cyclones on the tropopause parameters is observed to be more prominent within 500 km of the centre of the tropical cyclone. In our earlier study, we observed a decrease (increase in the tropopause altitude (temperature up to 0.6 km (3 K, and the convective outflow level increased up to 2 km. This change leads to a total increase in the tropical tropopause layer (TTL thickness of 3 km within 500 km of the centre of cyclone. Interestingly, an enhancement in the ozone mixing ratio in the upper troposphere is clearly noticed within 500 km from the cyclone centre, whereas the enhancement in the water vapour in the lower stratosphere is more significant on the south-east side, extending from 500 to 1000 km away from the cyclone centre. The cross-tropopause mass flux for different intensities of cyclones is estimated and it is found that the mean flux from the stratosphere to the troposphere for cyclonic storms is 0.05 ± 0.29 × 10−3 kg m−2, and for very severe cyclonic storms it is 0.5 ± 1.07 × 10−3 kg m−2. More downward flux is noticed on the north-west and south-west side of the cyclone centre. These results indicate that the cyclones have significant impact in effecting the tropopause structure, ozone and water vapour budget, and

Satellite Air Quality Monitoring Before, During and After the Beijing 2008 Olympics and Paralympics

Science.gov (United States)

Witte, J. C.; Schoeberl, M. R.; Krotkov, N. A.; Pickering, K. E.; Streets, D. G.; Gleason, J. F.; Gille, J. C.

2009-12-01

In 2001, Beijing, China was awarded the hosting rights to the 2008 Olympic and Paralympic Games. Since then, the government has gradually implemented pollution emission control strategies to improve Beijing's air quality in preparation for both games. Long-term industrial and short-term vehicle emission controls have also been enforced upwind of Beijing's neighboring provinces to the south and west. This region is characterized by numerous heavy-polluting industries whose emissions are typically transported towards Beijing, significantly impacting the city's air quality. We examine the efficacy of these emission control measures on tropospheric NO2, SO2, and CO pollution using satellite data from Aura's Ozone Monitoring Instrument (OMI) and Terra's Measurements Of Pollution In The Troposphere (MOPITT) from 2004 to the present. During both games, held in August and September 2008, OMI and MOPITT measured significant decreases in all three tracer gases compared to the past three years: NO2 (-43%), SO2 (-13%), and CO (-12%). This decrease in CO and SO2 over northeastern China continues through 2009, reflecting the longer-term nature of emission controls on heavily polluting industries. The global recession is also a likely contributor, as factories have shut down or slowed production due to the decrease in demand for manufactured goods. The tropospheric NO2 column over Beijing returned to typical monthly mean values when controls on vehicle emissions were lifted by the end of September 2008. However, we observe a slight NO2 decrease at the beginning of 2009 relative to 2008 suggesting a decrease in the contribution of industrial emissions of NOx to the overall NO2 column.

Relating tropical ocean clouds to moist processes using water vapor isotope measurements

Directory of Open Access Journals (Sweden)

J. Lee

2011-01-01

Full Text Available We examine the co-variations of tropospheric water vapor, its isotopic composition and cloud types and relate these distributions to tropospheric mixing and distillation models using satellite observations from the Aura Tropospheric Emission Spectrometer (TES over the summertime tropical ocean. Interpretation of these process distributions must take into account the sensitivity of the TES isotope and water vapor measurements to variations in cloud, water, and temperature amount. Consequently, comparisons are made between cloud-types based on the International Satellite Cloud Climatology Project (ISSCP classification; these are clear sky, non-precipitating (e.g., cumulus, boundary layer (e.g., stratocumulus, and precipitating clouds (e.g. regions of deep convection. In general, we find that the free tropospheric vapor over tropical oceans does not strictly follow a Rayleigh model in which air parcels become dry and isotopically depleted through condensation. Instead, mixing processes related to convection as well as subsidence, and re-evaporation of rainfall associated with organized deep convection all play significant roles in controlling the water vapor distribution. The relative role of these moisture processes are examined for different tropical oceanic regions.

Effects of regional-scale and convective transports on tropospheric ozone chemistry revealed by aircraft observations during the wet season of the AMMA campaign

Directory of Open Access Journals (Sweden)

G. Ancellet

2009-01-01

Full Text Available The African Monsoon Multidisciplinary Analyses (AMMA fourth airborne campaign was conducted in July–August 2006 to study the chemical composition of the middle and upper troposphere in West Africa with the major objective to better understand the processing of chemical emissions by the West African Monsoon (WAM and its associated regional-scale and vertical transports. In particular, the french airborne experiment was organized around two goals. The first was to characterize the impact of Mesoscale Convective Systems (MCSs on the ozone budget in the upper troposphere and the evolution of the chemical composition of these convective plumes as they move westward toward the Atlantic Ocean. The second objective was to discriminate the impact of remote sources of pollution over West Africa, including transport from the middle east, Europe, Asia and from southern hemispheric fires. Observations of O₃, CO, NO_x, H₂O and hydroperoxide above West Africa along repeated meridional transects were coupled with transport analysis based on the FLEXPART lagrangian model. The cross analysis of trace gas concentrations and transport pathways revealed 5 types of air masses: convective uplift of industrial and urban emissions, convective uplift of biogenic emissions, slow advection from Cotonou polluted plumes near the coast, meridional transport of upper tropospheric air from the subtropical barrier region, and meridional transport of Southern Hemisphere (SH biomass burning emissions. O₃/CO correlation plots and the correlation plots of H₂O₂ with a OH proxy revealed not only a control of the trace gas variability by transport processes but also significant photochemical reactivity in the mid- and upper troposphere. The study of four MCSs outflow showed contrasted chemical composition and air mass origins depending on the MCSs lifetime and latitudinal position. Favorables conditions for ozone

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.......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...

OMI/Aura Ozone (O3) DOAS Total Column Daily L2 Global 0.25 deg Lat/Lon Grid V003

Data.gov (United States)

National Aeronautics and Space Administration — The OMI/Aura Level-2G Total Column Ozone Data Product OMDOAO3G (Version 003) is now available ( http://disc.gsfc.nasa.gov/Aura/OMI/omdoao3g_v003.shtml ) from the...

Aqua/Aura Updated Inclination Adjust Maneuver Performance Prediction Model

Science.gov (United States)

Boone, Spencer

2017-01-01

This presentation will discuss the updated Inclination Adjust Maneuver (IAM) performance prediction model that was developed for Aqua and Aura following the 2017 IAM series. This updated model uses statistical regression methods to identify potential long-term trends in maneuver parameters, yielding improved predictions when re-planning past maneuvers. The presentation has been reviewed and approved by Eric Moyer, ESMO Deputy Project Manager.

Representativeness of the IAGOS airborne measurements in the lower troposphere

OpenAIRE

Petetin, H.; Jeoffrion, M.; Sauvage, B.; Athier, G.; Blot, R.; Boulanger, D.; Clark, H.; Cousin, J.-M.; Gheusi, F.; Nedelec, P.; Steinbacher, M.; Thouret, V.

2018-01-01

In the framework of the In Service Aircraft for Global Observing System (IAGOS) program, airborne in-situ O3 and CO measurements are performed routinely using in-service aircraft, providing vertical profiles from the surface to about 10–12 km. Due to the specificity of IAGOS measurements (measurements around busy international airports), uncertainties exist on their representativeness in the lower troposphere as they may be impacted by emissions related to airport activities and/or other air...

MLS/Aura L2 Chlorine Monoxide (ClO) Mixing Ratio V002

Data.gov (United States)

National Aeronautics and Space Administration — ML2CLO is the EOS Aura Microwave Limb Sounder (MLS) standard product for chlorine monoxide derived from radiances measured primarily by the 640 GHz radiometer. The...

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

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 ANOVA and multiple range test) than controls, whereas migraineurs without......-nitroglycerin-provoked healthy controls (p > 0.05, ANOVA and multiple range test). The exaggerated response in migraine with aura might predispose for the characteristic changes in rCBF seen during attacks....

OMI/Aura Sulphur Dioxide (SO2) Total Column Daily L2 Global 0.125 deg Lat/Lon Grid V003

Data.gov (United States)

National Aeronautics and Space Administration — The OMI/Aura Level-2G SO2 Data Product OMSO2G (Version 003) is now available http://disc.gsfc.nasa.gov/Aura/OMI/omso2g_v003.shtml ) from the NASA Goddard Earth...

Retrieval of global upper tropospheric and stratospheric formaldehyde (H2CO distributions from high-resolution MIPAS-Envisat spectra

Directory of Open Access Journals (Sweden)

G. P. Stiller

2008-02-01

Full Text Available The Fourier transform spectrometer MIPAS (Michelson Interferometer for Passive Atmospheric Sounding on Envisat measures infrared emission of the Earth's atmosphere in a limb viewing mode. High spectral resolution measurements of MIPAS are sensitive to formaldehyde from the upper troposphere to the stratopause. Single profile retrievals of formaldehyde are dominated by a 60% noise error; however zonal mean values for 30 days of data during 8 September 2003 and 1 December 2003 reduces this error by a factor of 20 or more. The number of degrees of freedom for single profile retrieval ranges from 2 to 4.5 depending on latitude and number of cloud-free tangent altitudes. In the upper tropical troposphere zonal mean values of about 70 parts per trillion by volume (pptv were found, which have been attributed to biomass burning emissions. In the stratosphere, formaldehyde values are determined by photochemical reactions. In the upper tropical stratosphere, formaldehyde zonal mean maximum values can reach 130 pptv. Diurnal variations in this region can be up to 50 pptv. Comparisons with other satellite instruments show generally good agreement in the region of upper troposphere and lower stratosphere as well as in the upper stratosphere.

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

The use of satellite data to determine the distribution of ozone in the troposphere

Science.gov (United States)

Fishman, Jack; Watson, Catherine E.; Brackett, Vincent G.; Fakhruzzaman, Khan; Veiga, Robert E.

1991-01-01

Measurements from two independent satellite data sets have been used to derive the climatology of the integrated amount of ozone in the troposphere. These data have led to the finding that large amounts of ozone pollution are generated by anthropogenic activity originating from both the industrialized regions of the Northern Hemisphere and from the southern tropical regions of Africa. To verify the existence of this ozone anomaly at low latitudes, an ozonesonde capability has been established at Ascension Island (8 deg S, 15 deg W) since July 1990. According to the satellite analyses, Ascension Island is located downwind of the primary source region of this ozone pollution, which likely results from the photochemical oxidation of emissions emanating from the widespread burning of savannas and other biomass. These in situ measurements confirm the existence of large amounts of ozone in the lower atmosphere. A summary of these ozonesonde data to date will be presented. In addition, we will present some ozone profile measurements from SAGE II which can be used to provide upper tropospheric ozone measurements directly in the tropical troposphere. A preliminary comparison between the satellite observations and the ozonesonde profiles in the upper troposphere and lower stratosphere will also be presented.

Future Climate Impacts of Direct Radiative Forcing Anthropogenic Aerosols, Tropospheric Ozone, and Long-lived Greenhouse Gases

Science.gov (United States)

Chen, Wei-Ting; Liao, Hong; Seinfeld, John H.

2007-01-01

Long-lived greenhouse gases (GHGs) are the most important driver of climate change over the next century. Aerosols and tropospheric ozone (O3) are expected to induce significant perturbations to the GHG-forced climate. To distinguish the equilibrium climate responses to changes in direct radiative forcing of anthropogenic aerosols, tropospheric ozone, and GHG between present day and year 2100, four 80-year equilibrium climates are simulated using a unified tropospheric chemistry-aerosol model within the Goddard Institute for Space Studies (GISS) general circulation model (GCM) 110. Concentrations of sulfate, nitrate, primary organic (POA) carbon, secondary organic (SOA) carbon, black carbon (BC) aerosols, and tropospheric ozone for present day and year 2100 are obtained a priori by coupled chemistry-aerosol GCM simulations, with emissions of aerosols, ozone, and precursors based on the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenario (SRES) A2. Changing anthropogenic aerosols, tropospheric ozone, and GHG from present day to year 2100 is predicted to perturb the global annual mean radiative forcing by +0.18 (considering aerosol direct effects only), +0.65, and +6.54 W m(sup -2) at the tropopause, and to induce an equilibrium global annual mean surface temperature change of +0.14, +0.32, and +5.31 K, respectively, with the largest temperature response occurring at northern high latitudes. Anthropogenic aerosols, through their direct effect, are predicted to alter the Hadley circulation owing to an increasing interhemispheric temperature gradient, leading to changes in tropical precipitation. When changes in both aerosols and tropospheric ozone are considered, the predicted patterns of change in global circulation and the hydrological cycle are similar to those induced by aerosols alone. GHG-induced climate changes, such as amplified warming over high latitudes, weakened Hadley circulation, and increasing precipitation over the

How Can TOLNet Help to Better Understand Tropospheric Ozone? A Satellite Perspective

Science.gov (United States)

Johnson, Matthew S.

2018-01-01

Potential sources of a priori ozone (O3) profiles for use in Tropospheric Emissions: Monitoring of Pollution (TEMPO) satellite tropospheric O3 retrievals are evaluated with observations from multiple Tropospheric Ozone Lidar Network (TOLNet) systems in North America. An O3 profile climatology (tropopause-based O3 climatology (TB-Clim), currently proposed for use in the TEMPO O3 retrieval algorithm) derived from ozonesonde observations and O3 profiles from three separate models (operational Goddard Earth Observing System (GEOS-5) Forward Processing (FP) product, reanalysis product from Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA2), and the GEOS-Chem chemical transport model (CTM)) were: 1) evaluated with TOLNet measurements on various temporal scales (seasonally, daily, hourly) and 2) implemented as a priori information in theoretical TEMPO tropospheric O3 retrievals in order to determine how each a priori impacts the accuracy of retrieved tropospheric (0-10 km) and lowermost tropospheric (LMT, 0-2 km) O3 columns. We found that all sources of a priori O3 profiles evaluated in this study generally reproduced the vertical structure of summer-averaged observations. However, larger differences between the a priori profiles and lidar observations were observed when evaluating inter-daily and diurnal variability of tropospheric O3. The TB-Clim O3 profile climatology was unable to replicate observed inter-daily and diurnal variability of O3 while model products, in particular GEOS-Chem simulations, displayed more skill in reproducing these features. Due to the ability of models, primarily the CTM used in this study, on average to capture the inter-daily and diurnal variability of tropospheric and LMT O3 columns, using a priori profiles from CTM simulations resulted in TEMPO retrievals with the best statistical comparison with lidar observations. Furthermore, important from an air quality perspective, when high LMT O3 values were

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...

Climatology 2011: An MLS and Sonde Derived Ozone Climatology for Satellite Retrieval Algorithms

Science.gov (United States)

McPeters, Richard D.; Labow, Gordon J.

2012-01-01

The ozone climatology used as the a priori for the version 8 Solar Backscatter Ultraviolet (SBUV) retrieval algorithms has been updated. The Microwave Limb Sounder (MLS) instrument on Aura has excellent latitude coverage and measures ozone daily from the upper troposphere to the lower mesosphere. The new climatology consists of monthly average ozone profiles for ten degree latitude zones covering pressure altitudes from 0 to 65 km. The climatology was formed by combining data from Aura MLS (2004-2010) with data from balloon sondes (1988-2010). Ozone below 8 km (below 12 km at high latitudes) is based on balloons sondes, while ozone above 16 km (21 km at high latitudes) is based on MLS measurements. Sonde and MLS data are blended in the transition region. Ozone accuracy in the upper troposphere is greatly improved because of the near uniform coverage by Aura MLS, while the addition of a large number of balloon sonde measurements improves the accuracy in the lower troposphere, in the tropics and southern hemisphere in particular. The addition of MLS data also improves the accuracy of climatology in the upper stratosphere and lower mesosphere. The revised climatology has been used for the latest reprocessing of SBUV and TOMS satellite ozone data.

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

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 + NO{sub 2} and HNO{sub 3}. At northern mid- and high latitudes, the calculated tropospheric NO{sub x} content is dominated by the surface source fossil fuel combustion. In the tropical free troposphere lightning discharges provide about 80% of the total NO{sub x} throughout the year. The zonally averaged fractional contribution of aircraft emissions strongly depends on season. The NO mixing ratios determined by the model show good overall agreement with corresponding zonal mean values observed during the STRATOZ III aircraft campaign in June. Over Canada, mixing ratios as high as 0.5-1.0 ppbv NO were measured during TROPOZ II, the origin of which is not yet understood. (author) 8 refs.

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

1998-12-31

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 + NO{sub 2} and HNO{sub 3}. At northern mid- and high latitudes, the calculated tropospheric NO{sub x} content is dominated by the surface source fossil fuel combustion. In the tropical free troposphere lightning discharges provide about 80% of the total NO{sub x} throughout the year. The zonally averaged fractional contribution of aircraft emissions strongly depends on season. The NO mixing ratios determined by the model show good overall agreement with corresponding zonal mean values observed during the STRATOZ III aircraft campaign in June. Over Canada, mixing ratios as high as 0.5-1.0 ppbv NO were measured during TROPOZ II, the origin of which is not yet understood. (author) 8 refs.

Tropospheric Ozone from the TOMS TDOT (TOMS-Direct-Ozone-in-Troposphere) Technique During SAFARI-2000

Science.gov (United States)

Stone, J. B.; Thompson, A. M.; Frolov, A. D.; Hudson, R. D.; Bhartia, P. K. (Technical Monitor)

2002-01-01

There are a number of published residual-type methods for deriving tropospheric ozone from TOMS (Total Ozone Mapping Spectrometer). The basic concept of these methods is that within a zone of constant stratospheric ozone, the tropospheric ozone column can be computed by subtracting stratospheric ozone from the TOMS Level 2 total ozone column, We used the modified-residual method for retrieving tropospheric ozone during SAFARI-2000 and found disagreements with in-situ ozone data over Africa in September 2000. Using the newly developed TDOT (TOMS-Direct-Ozone-in-Troposphere) method that uses TOMS radiances and a modified lookup table based on actual profiles during high ozone pollution periods, new maps were prepared and found to compare better to soundings over Lusaka, Zambia (15.5 S, 28 E), Nairobi and several African cities where MOZAIC aircraft operated in September 2000. The TDOT technique and comparisons are described in detail.

Chemical and climatic drivers of radiative forcing due to changes in stratospheric and tropospheric ozone over the 21st century

Directory of Open Access Journals (Sweden)

A. Banerjee

2018-02-01

Full Text Available The ozone radiative forcings (RFs resulting from projected changes in climate, ozone-depleting substances (ODSs, non-methane ozone precursor emissions and methane between the years 2000 and 2100 are calculated using simulations from the UM-UKCA chemistry–climate model (UK Met Office's Unified Model containing the United Kingdom Chemistry and Aerosols sub-model. Projected measures to improve air-quality through reductions in non-methane tropospheric ozone precursor emissions present a co-benefit for climate, with a net global mean ozone RF of −0.09 W m−2. This is opposed by a positive ozone RF of 0.05 W m−2 due to future decreases in ODSs, which is driven by an increase in tropospheric ozone through stratosphere-to-troposphere transport of air containing higher ozone amounts. An increase in methane abundance by more than a factor of 2 (as projected by the RCP8.5 scenario is found to drive an ozone RF of 0.18 W m−2, which would greatly outweigh the climate benefits of non-methane tropospheric ozone precursor reductions. A small fraction (∼ 15 % of the ozone RF due to the projected increase in methane results from increases in stratospheric ozone. The sign of the ozone RF due to future changes in climate (including the radiative effects of greenhouse gases, sea surface temperatures and sea ice changes is shown to be dependent on the greenhouse gas emissions pathway, with a positive RF (0.05 W m−2 for RCP4.5 and a negative RF (−0.07 W m−2 for the RCP8.5 scenario. This dependence arises mainly from differences in the contribution to RF from stratospheric ozone changes. Considering the increases in tropopause height under climate change causes only small differences (≤ |0.02| W m−2 for the stratospheric, tropospheric and whole-atmosphere RFs.

Decadal trends in tropospheric ozone over East Asian Pacific rim during 1998-2007: Implications for emerging Asian emissions impacts and comparison to European and North American records (Invited)

Science.gov (United States)

Tanimoto, H.; Ohara, T.; Uno, I.

2010-12-01

We examine springtime ozone trends at nine remote locations in East Asian Pacific rim during the last decade (1998-2007). The observed decadal ozone trends are relatively small at surface sites but are substantially larger at a mountainous site. The level and increasing rate of ozone at the mountainous site are both higher than those observed at background sites in Europe and North America. We use a regional chemistry-transport model to explore the observed changes and how changes in Asian anthropogenic emissions have contributed to the observed increasing trends. The model with yearly-dependent regional emissions successfully reproduces the levels, variability, and interannual variations of ozone at all the surface sites. It predicts increasing trends at the mountainous site, suggesting that increasing Asian anthropogenic emissions account for about half the observed increase. However, the discrepancy between the observation and model results after 2003 (the time of largest emission increase) suggests significant underestimation of the actual growth of the Asian anthropogenic emissions and/or incompleteness in the modeling of pollution export from continental Asia. These findings imply that improving emissions inventory and transport scheme is needed to better understand rapidly evolving tropospheric ozone in East Asia and its potential climatic and environmental impacts.

MLS/Aura L2 Nitric Acid (HNO3) Mixing Ratio V003

Data.gov (United States)

National Aeronautics and Space Administration — ML2HNO3 is the EOS Aura Microwave Limb Sounder (MLS) standard product for nitric acid derived from radiances measured by the 240 GHz radiometer at and below 10 hPa,...

MLS/Aura Level 2 Nitric Acid (HNO3) Mixing Ratio V004

Data.gov (United States)

National Aeronautics and Space Administration — ML2HNO3 is the EOS Aura Microwave Limb Sounder (MLS) standard product for nitric acid derived from radiances measured by the 240 GHz radiometer at and below 10 hPa,...

MLS/Aura L2 Nitric Acid (HNO3) Mixing Ratio V002

Data.gov (United States)

National Aeronautics and Space Administration — ML2HNO3 is the EOS Aura Microwave Limb Sounder (MLS) standard product for nitric acid derived from radiances measured by the 240 GHz radiometer at and below 10 hPa,...

Focal plane subsystem design and performance for atmospheric chemistry from geostationary orbit tropospheric emissions monitoring of pollution

Science.gov (United States)

Gilmore, A. S.; Philbrick, R. H.; Funderburg, J.

2017-09-01

Remote sensing of pollutants are enabled from a satellite in a geostationary orbit containing an imaging spectrometer encompassing the wavelength ranges of 290 - 490 nm and 540 - 740 nm. As the first of NASA's Earth Venture Instrument Program, the Tropospheric Emissions: Monitoring of Pollution (TEMPO) program will utilize this instrument to measure hourly air quality over a large portion of North America. The focal plane subsystem (FPS) contains two custom designed and critically aligned full frame transfer charge coupled devices (active area: 1028 x 2048, 18 μm) within a focal plane array package designed for radiation tolerance and space charging rejection. In addition, the FPS contains custom distributed focal plane electronics that provide all necessary clocks and biases to the sensors, receives all analog data from the sensors and performs 14 bit analog to digital conversion for upstream processing. Finally, the FPS encompasses custom low noise cables connecting the focal plane array and associated electronics. This paper discusses the design and performance of this novel focal plane subsystem with particular emphasis on the optical performance achieved including alignment, quantum efficiency, and modulation transfer function.

OMI/Aura Level 1B UV Global Geolocated Earthshine Radiances 1-orbit L2 Swath 13x24 km V003

Data.gov (United States)

National Aeronautics and Space Administration — The Level-1B (L1B) Radiance Product OML1BRUG (Version-3) from the Aura-OMI is now available to public (http://disc.gsfc.nasa.gov/Aura/OMI/oml1brug_v003.shtml) from...

Evaluation of the Ozone Fields in NASA's MERRA-2 Reanalysis

Science.gov (United States)

Wargan, Krzysztof; Labow, Gordon; Frith, Stacey; Pawson, Steven; Livesey, Nathaniel; Partyka, Gary

2017-01-01

We describe and assess the quality of the assimilated ozone product from the Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA-2) produced at NASAs Global Modeling and Assimilation Office (GMAO) spanning the time period from 1980 to present. MERRA-2 assimilates partial column ozone retrievals from a series of Solar Backscatter Ultraviolet (SBUV) radiometers on NASA and NOAA spacecraft between January 1980 and September 2004; starting in October 2004 retrieved ozone profiles from the Microwave Limb Sounder (MLS) and total column ozone from the Ozone Monitoring Instrument on NASAs EOS Aura satellite are assimilated. We compare the MERRA-2 ozone with independent satellite and ozonesonde data focusing on the representation of the spatial and temporal variability of stratospheric and upper tropospheric ozone and on implications of the change in the observing system from SBUV to EOS Aura. The comparisons show agreement within 10 (standard deviation of the difference) between MERRA-2 profiles and independent satellite data in most of the stratosphere. The agreement improves after 2004 when EOS Aura data are assimilated. The standard deviation of the differences between the lower stratospheric and upper tropospheric MERRA-2 ozone and ozonesondes is 11.2 and 24.5, respectively, with correlations of 0.8 and above, indicative of a realistic representation of the near-tropopause ozone variability in MERRA-2. The agreement improves significantly in the EOS Aura period, however MERRA-2 is biased low in the upper troposphere with respect to the ozonesondes. Caution is recommended when using MERRA-2 ozone for decadal changes and trend studies.

Tropospheric NO2 over China

NARCIS (Netherlands)

A, van der R.J.; Peters, D.H.M.U.; Kuenen, J.J.P.; Eskes, H.J.; Boersma, K.F.; Roozendael, Van M.; Smedt, de I.; Zhang, P.; Kelder, H.M.; Lacoste, H.; Ouwehand, L.

2006-01-01

The results are presented of a study to tropospheric NO2 over China, based on measurements from the satellite instruments GOME and SCIAMACHY. A data set of 10 year tropospheric NO2 has been processed from GOME and SCIAMACHY observations using a combined retrieval/assimilation approach. This approach

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

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.

Southern Hemisphere Carbon Monoxide Inferannual Variability Observed by Terra/Measurement of Pollution in the Troposphere (MOPITT)

Science.gov (United States)

Edwards, D. P.; Petron, G.; Novelli, P. C.; Emmons, L. K.; Gille, J. C.; Drummond, J. R.

2010-01-01

Biomass burning is an annual occurrence in the tropical southern hemisphere (SH) and represents a major source of regional pollution. Vegetation fires emit carbon monoxide (CO), which due to its medium lifetime is an excellent tracer of tropospheric transport. CO is also one of the few tropospheric trace gases currently observed from satellite and this provides long-term global measurements. In this paper, we use the 5 year CO data record from the Measurement Of Pollution In The Troposphere (MOPITT) instrument to examine the inter-annual variability of the SH CO loading and show how this relates to climate conditions which determine the intensity of fire sources. The MOPITT observations show an annual austral springtime peak in the SH zonal CO loading each year with dry-season biomass burning emissions in S. America, southern Africa, the Maritime Continent, and northwestern Australia. Although fires in southern Africa and S. America typically produce the greatest amount of CO, the most significant inter-annual variation is due to varying fire activity and emissions from the Maritime Continent and northern Australia. We find that this variation in turn correlates well with the El Nino Southern Oscillation precipitation index. Between 2000 and 2005, emissions were greatest in late 2002 and an inverse modeling of the MOPITT data using the MOZART chemical transport model estimates the southeast Asia regional fire source for the year August 2002 to September 2003 to be 52 Tg CO. Comparison of the MOPITT retrievals and NOAA surface network measurements indicate that the latter do not fully capture the inter-annual variability or the seasonal range of the CO zonal average concentration due to biases associated with atmospheric and geographic sampling.

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

On the use of Satellite Remote Sensing and GIS to detect NO2 in the Troposphere

DEFF Research Database (Denmark)

Nielsen, Søren Zebitz

2012-01-01

This thesis studies the spatio-temporal patterns and trends in NO2 air pollution over Denmark using the satellite remote sensing product OMNO2e retrieved from the OMI instrument on the NASA AURA satellite. These data are related to in situ measurements of NO2 made at four rural and four urban...... measured in Denmark. Trends in the data are assessed and declining trends are seen over several European cities, whereas no significant trends are found in the Danish area. The mean distribution of NO2 from the satellite data is also used to evaluate the NOx emission inventory....

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

OMI/Aura Level 1B VIS Zoom-in Geolocated Earthshine Radiances 1-orbit L2 Swath 13x12 km V003

Data.gov (United States)

National Aeronautics and Space Administration — The Level-1B (L1B) Radiance Product OML1BRVZ (Version-3) from the Aura-OMI is now available (http://disc.gsfc.nasa.gov/Aura/OMI/oml1brvz_v003.shtml) to public from...

OMI/Aura Level 1B UV Zoom-in Geolocated Earthshine Radiances 1-orbit L2 Swath 13x12 km V003

Data.gov (United States)

National Aeronautics and Space Administration — The Level-1B (L1B) Radiance Product OML1BRUZ (Version-3) from the Aura-OMI is now available (http://disc.gsfc.nasa.gov/Aura/OMI/oml1bruz_v003.shtml) to public from...

New Particle Formation in the Mid-Latitude Upper Troposphere

Science.gov (United States)

Axisa, Duncan

Primary aerosol production due to new particle formation (NPF) in the upper troposphere and the impact that this might have on cloud condensation nuclei (CCN) concentration can be of sufficient magnitude to contribute to the uncertainty in radiative forcing. This uncertainty affects our ability to estimate how sensitive the climate is to greenhouse gas emissions. Therefore, new particle formation must be accurately defined, parametrized and accounted for in models. This research involved the deployment of instruments, data analysis and interpretation of particle formation events during the Mid-latitude Airborne Cirrus Properties Experiment (MACPEX) campaign. The approach combined field measurements and observations with extensive data analysis and modeling to study the process of new particle formation and growth to CCN active sizes. Simultaneous measurements of O3, CO, ultrafine aerosol particles and surface area from a high-altitude research aircraft were used to study tropospheric-stratospheric mixing as well as the frequency and location of NPF. It was found that the upper troposphere was an active region in the production of new particles by gas-to-particle conversion, that nucleation was triggered by convective clouds and mixing processes, and that NPF occurred in regions with high relative humidity and low surface area. In certain cases, mesoscale and synoptic features enhanced mixing and facilitated the formation of new particles in the northern mid-latitudes. A modeling study of particle growth and CCN formation was done based on measured aerosol size distributions and modeled growth. The results indicate that when SO2 is of sufficient concentration NPF is a significant source of potential CCN in the upper troposphere. In conditions where convective cloud outflow eject high concentrations of SO2, a large number of new particles can form especially in the instance when the preexisting surface area is low. The fast growth of nucleated clusters produces a

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.

MLS/Aura Level 2 Nitrous Oxide (N2O) Mixing Ratio V004

Data.gov (United States)

National Aeronautics and Space Administration — ML2N2O is the EOS Aura Microwave Limb Sounder (MLS) standard product for nitrous oxide derived from radiances measured primarily by the 640 GHz radiometer (Band 12)...

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.

Mission Status for Earth Science Constellation MOWG Meeting at KSC: EOS Aura

Science.gov (United States)

Fisher, Dominic

2017-01-01

This will be presented at the Earth Science Constellation Mission Operations Working Group (MOWG) meeting at KSC (Kennedy Space Center) in December 2017 to discus EOS (Earth Observing System) Aura status. Reviewed and approved by Eric Moyer, ESMO (Earth Sciences Mission Operations) Deputy Project Manager.

The Governing Processes and Timescales of Stratosphere-to-Troposphere Transport and its Contribution to Ozone in the Arctic Troposphere

Science.gov (United States)

Liang, Q.; Douglass, A. R.; Duncan, B. N.; Stolarski, R. S.; Witte, J. C.

2009-01-01

We used the seasonality of a combination of atmospheric trace gases and idealized tracers to examine stratosphere-to-troposphere transport and its influence on tropospheric composition in the Arctic. Maximum stratosphere-to-troposphere transport of CFCs and O3 occurs in April as driven by the Brewer-Dobson circulation. Stratosphere-troposphere exchange (STE) occurs predominantly between 40 deg N to 80 deg N with stratospheric influx in the mid-latitudes (30-70 deg N) accounting for 67.81 percent of the air of stratospheric origin in the Northern Hemisphere extratropical troposphere. Transport from the lower stratosphere to the lower troposphere (LT) takes three months on average, one month to cross the tropopause, the second month to travel from the upper troposphere (UT) to the middle troposphere (MT), and the third month to reach the LT. During downward transport, the seasonality of a trace gas can be greatly impacted by wet removal and chemistry. A comparison of idealized tracers with varying lifetimes suggests that when initialized with the same concentrations and seasonal cycles at the tropopause, trace gases that have shorter lifetimes display lower concentrations, smaller amplitudes, and earlier seasonal maxima during transport to the LT. STE contributes to O3 in the Arctic troposphere directly from the transport of O3 and indirectly from the transport of NOy . Direct transport of O3 from the stratosphere accounts for 78 percent of O3 in the Arctic UT with maximum contributions occurring from March to May. The stratospheric contribution decreases significantly in the MT/LT (20.25 percent of total O3) and shows a very weak March.April maximum. Our NOx budget analysis in the Arctic UT shows that during spring and summer, the stratospheric injection of NO y-rich air increases NOx concentrations above the 20 pptv threshold level, thereby shifting the Arctic UT from a regime of net photochemical ozone loss to one of net production with rates as high as +16 ppbv/month.

The governing processes and timescales of stratosphere-to-troposphere transport and its contribution to ozone in the Arctic troposphere

Science.gov (United States)

Liang, Q.; Douglass, A. R.; Duncan, B. N.; Stolarski, R. S.; Witte, J. C.

2009-05-01

We used the seasonality of a combination of atmospheric trace gases and idealized tracers to examine stratosphere-to-troposphere transport and its influence on tropospheric composition in the Arctic. Maximum stratosphere-to-troposphere transport of CFCs and O3 occurs in April as driven by the Brewer-Dobson circulation. Stratosphere-troposphere exchange (STE) occurs predominantly between 40° N to 80° N with stratospheric influx in the mid-latitudes (30-70° N) accounting for 67-81% of the air of stratospheric origin in the Northern Hemisphere extratropical troposphere. Transport from the lower stratosphere to the lower troposphere (LT) takes three months on average, one month to cross the tropopause, the second month to travel from the upper troposphere (UT) to the middle troposphere (MT), and the third month to reach the LT. During downward transport, the seasonality of a trace gas can be greatly impacted by wet removal and chemistry. A comparison of idealized tracers with varying lifetimes suggests that when initialized with the same concentrations and seasonal cycles at the tropopause, trace gases that have shorter lifetimes display lower concentrations, smaller amplitudes, and earlier seasonal maxima during transport to the LT. STE contributes to O3 in the Arctic troposphere directly from the transport of O3 and indirectly from the transport of NOy. Direct transport of O3 from the stratosphere accounts for 78% of O3 in the Arctic UT with maximum contributions occurring from March to May. The stratospheric contribution decreases significantly in the MT/LT (20-25% of total O3) and shows a very weak March-April maximum. Our NOx budget analysis in the Arctic UT shows that during spring and summer, the stratospheric injection of NOy-rich air increases NOx concentrations above the 20 pptv threshold level, thereby shifting the Arctic UT from a regime of net photochemical ozone loss to one of net production with rates as high as +16 ppbv/month.

Acetone in theGlobal Troposphere: Its Possible Role as a Global Source of PAN

Science.gov (United States)

Singh, H. B.; Kanakidou, M.

1994-01-01

Oxygenated hydrocarbons are thought to be important components of the atmosphere but, with the exception of formaldehyde, very little about their distribution and fate is known. Aircraft measurements of acetone (CH3COCH3), PAN (CH3CO3NO2) and other organic species (e. g. acetaldehyde, methanol and ethanol) have been performed over the Pacific, the southern Atlantic, and the subarctic atmospheres. Sampled areas extended from 0 to 12 km altitude over latitudes of 70 deg N to 40 deg S. All measurements are based on real time in-situ analysis of cryogenically preconcentrated air samples. Substantial concentrations of these oxygenated species (10-2000 ppt) have been observed at all altitudes and geographical locations in the troposphere. Important sources include, emissions from biomass burning, plant and vegetation, secondary oxidation of primary non-methane hydrocarbons, and man-made emissions. Direct measurements within smoke plumes have been used to estimate the biomass burning source. Photochemistry studies are used to suggest that acetone could provide a major source of peroxyacetyl radicals in the atmosphere and play an important role in sequestering reactive nitrogen. Model calculations show that acetone photolysis contributes significantly to PAN formation in the middle and upper troposphere.

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.

OMI/Aura Cloud Pressure and Fraction (O2-O2 Absorption) Zoomed 1-Orbit L2 Swath 13x12km V003

Data.gov (United States)

National Aeronautics and Space Administration — The reprocessed OMI/Aura Level-2 zoomed cloud data product OMCLDO2Z at 13x12 km resolution is now available ( http://disc.gsfc.nasa.gov/Aura/OMI/omcldo2z_v003.shtml...

OMI/Aura Cloud Pressure and Fraction (O2-O2 Absorption) Daily L2 Global 0.25 deg Lat/Lon Grid V003

Data.gov (United States)

National Aeronautics and Space Administration — The reprocessed OMI/Aura Level-2G cloud data product OMCLDO2G, is now available (http://disc.gsfc.nasa.gov/Aura/OMI/omcldo2g_v003.shtml) from the NASA Goddard Earth...

Ships going slow in reducing their NOx emissions

NARCIS (Netherlands)

Boersma, K.F.; Vinken, G.C.M.; Tournadre, J.

2015-01-01

Weaddress the lack of temporal information on ship emissions, and report on rapid short-term variations of satellite-derived shipNOx emissions between 2005 and 2012 over European seas. Our inversion is based onOMI observed troposphericNO2 columns and GEOS-Chem simulations. Average European shipNOx

Upper tropospheric cloud systems determined from IR Sounders and their influence on the atmosphere

Science.gov (United States)

Stubenrauch, Claudia; Protopapadaki, Sofia; Feofilov, Artem; Velasco, Carola Barrientos

2017-02-01

Covering about 30% of the Earth, upper tropospheric clouds play a key role in the climate system by modulating the Earth's energy budget and heat transport. Infrared Sounders reliably identify cirrus down to an IR optical depth of 0.1. Recently LMD has built global cloud climate data records from AIRS and IASI observations, covering the periods from 2003-2015 and 2008-2015, respectively. Upper tropospheric clouds often form mesoscale systems. Their organization and properties are being studied by (1) distinguishing cloud regimes within 2° × 2° regions and (2) applying a spatial composite technique on adjacent cloud pressures, which estimates the horizontal extent of the mesoscale cloud systems. Convective core, cirrus anvil and thin cirrus of these systems are then distinguished by their emissivity. Compared to other studies of tropical mesoscale convective systems our data include also the thinner anvil parts, which make out about 30% of the area of tropical mesoscale convective systems. Once the horizontal and vertical structure of these upper tropospheric cloud systems is known, we can estimate their radiative effects in terms of top of atmosphere and surface radiative fluxes and by computing their heating rates.

Evaluation of the Ozone Fields in NASA’s MERRA-2 Reanalysis

Science.gov (United States)

Wargan, Krzysztof; Labow, Gordon; Frith, Stacey; Pawson, Steven; Livesey, Nathaniel; Partyka, Gary

2018-01-01

We describe and assess the quality of the assimilated ozone product from the Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA-2) produced at NASA’s Global Modeling and Assimilation Office (GMAO) spanning the time period from 1980 to present. MERRA-2 assimilates partial column ozone retrievals from a series of Solar Backscatter Ultraviolet (SBUV) radiometers on NASA and NOAA spacecraft between January 1980 and September 2004; starting in October 2004 retrieved ozone profiles from the Microwave Limb Sounder (MLS) and total column ozone from the Ozone Monitoring Instrument on NASA’s EOS Aura satellite are assimilated. We compare the MERRA-2 ozone with independent satellite and ozonesonde data focusing on the representation of the spatial and temporal variability of stratospheric and upper tropospheric ozone and on implications of the change in the observing system from SBUV to EOS Aura. The comparisons show agreement within 10 % (standard deviation of the difference) between MERRA-2 profiles and independent satellite data in most of the stratosphere. The agreement improves after 2004 when EOS Aura data are assimilated. The standard deviation of the differences between the lower stratospheric and upper tropospheric MERRA-2 ozone and ozonesondes is 11.2 % and 24.5 %, respectively, with correlations of 0.8 and above, indicative of a realistic representation of the near-tropopause ozone variability in MERRA-2. The agreement improves significantly in the EOS Aura period, however MERRA-2 is biased low in the upper troposphere with respect to the ozonesondes. Caution is recommended when using MERRA-2 ozone for decadal changes and trend studies. PMID:29527096

Temperature Dependence of Factors Controlling Isoprene Emissions

Science.gov (United States)

Duncan, Bryan N.; Yoshida, Yasuko; Damon, Megan R.; Douglass, Anne R.; Witte, Jacquelyn C.

2009-01-01

We investigated the relationship of variability in the formaldehyde (HCHO) columns measured by the Aura Ozone Monitoring Instrument (OMI) to isoprene emissions in the southeastern United States for 2005-2007. The data show that the inferred, regional-average isoprene emissions varied by about 22% during summer and are well correlated with temperature, which is known to influence emissions. Part of the correlation with temperature is likely associated with other causal factors that are temperature-dependent. We show that the variations in HCHO are convolved with the temperature dependence of surface ozone, which influences isoprene emissions, and the dependence of the HCHO column to mixed layer height as OMI's sensitivity to HCHO increases with altitude. Furthermore, we show that while there is an association of drought with the variation in HCHO, drought in the southeastern U.S. is convolved with temperature.

Analysis of the Latitudinal Variability of Tropospheric Ozone in the Arctic Using the Large Number of Aircraft and Ozonesonde Observations in Early Summer 2008

Science.gov (United States)

Ancellet, Gerard; Daskalakis, Nikos; Raut, Jean Christophe; Quennehen, Boris; Ravetta, Francois; Hair, Jonathan; Tarasick, David; Schlager, Hans; Weinheimer, Andrew J.; Thompson, Anne M.;

Comparison of Ambu® AuraGain™ laryngeal mask and air-Q™ intubating laryngeal airway for blind tracheal intubation in adults: A randomized controlled trial

OpenAIRE

Sameer Sethi; Souvik Maitra; Vikas Saini; Tanvir Samara

2017-01-01

Background: This study has been designed to compare the performance of Ambu® AuraGain™ laryngeal mask with the air-Q™ as a conduit for blind tracheal intubation in adult patients. Methods: In this prospective randomized controlled trial blind endotracheal intubation success rates were compared between Ambu® AuraGain™ and air-Q™ intubating laryngeal airway in 90 adult patients. Patients were randomized in two equal groups: Group Ambu® AuraGain™ (n = 45) and Group air-Q™ (n = 45). Results...

The interhemispheric distribution and the budget of acetonitrile in the troposphere

International Nuclear Information System (INIS)

Hamm, S.; Warneck, P.

1990-01-01

Gas chromatography in conjunction with a thermionic nitrogen-specific detector was used to determine mixing ratios of acetonitrile in air samples collected in Europe and over the Atlantic Ocean. In the city of Mainz, values of the order of 340 pptv were observed with large variations indicating the vicinity of sources. In the rural community of Deuselbach the average mixing ratio was 147±28 pptv; over the North Sea the range was 65-196 pptv depending on wind direction. Over the open ocean, maximum mixing ratios were observed near 4 degree S with values of 175 pptv. At latitudes near 30 degree S the mixing ratio averaged 90.4 pptv, whereas at 30 degree N the average was 52.1 pptv. The lowest mixing ratios of 21 pptv were found near 50 degree N. The tropical maximum is attributed to the advection with the trade winds of continental air from Africa, enriched with acetonitrile form biomass burning. The mixing ratios north and south of the maximum correlate well with the surface temperature of seawater, indicating a gas-liquid equilibrium for CH 3 CN dissolved in seawater. From the observations and with the further assumption that CH 3 CN is vertically well mixed, its total mass content in the troposphere was estimated as 0.37-0.57 Tg. Global emission rates for various sources were estimated as follows: Automobiles 0.27 Tg/year, oil-fired power stations 0.0035 Tg/year, and biomass burning 0.80 Tg/year. The total estimated source strength is 1.1±0.5 Tg/year. The troposphere residence time of acetonitrile was calculated from these data as 0.23-0.90 year with a probable value of 0.45 year. Wet precipitation and reaction with OH radicals are known sinks for tropospheric CH 3 CN, but they can take up only 30% of the global emission rate. The authors suggest absorption in the ocean to be the major sink

Evaluating A Priori Ozone Profile Information Used in TEMPO Tropospheric Ozone Retrievals

Science.gov (United States)

Johnson, Matthew S.; Sullivan, John T.; Liu, Xiong; Newchurch, Mike; Kuang, Shi; McGee, Thomas J.; Langford, Andrew O'Neil; Senff, Christoph J.; Leblanc, Thierry; Berkoff, Timothy;

Evaluating A Priori Ozone Profile Information Used in TEMPO Tropospheric Ozone Retrievals

Science.gov (United States)

Johnson, M. S.; Sullivan, J. T.; Liu, X.; Newchurch, M.; Kuang, S.; McGee, T. J.; Langford, A. O.; Senff, C. J.; Leblanc, T.; Berkoff, T.; Gronoff, G.; Chen, G.; Strawbridge, K. B.

2016-12-01

Ozone (O3) is a greenhouse gas and toxic pollutant which plays a major role in air quality. Typically, monitoring of surface air quality and O3 mixing ratios is primarily conducted using in situ measurement networks. This is partially due to high-quality information related to air quality being limited from space-borne platforms due to coarse spatial resolution, limited temporal frequency, and minimal sensitivity to lower tropospheric and surface-level O3. The Tropospheric Emissions: Monitoring of Pollution (TEMPO) satellite is designed to address these limitations of current space-based platforms and to improve our ability to monitor North American air quality. TEMPO will provide hourly data of total column and vertical profiles of O3 with high spatial resolution to be used as a near-real-time air quality product. TEMPO O3 retrievals will apply the Smithsonian Astrophysical Observatory profile algorithm developed based on work from GOME, GOME-2, and OMI. This algorithm uses a priori O3 profile information from a climatological data-base developed from long-term ozone-sonde measurements (tropopause-based (TB) O3 climatology). It has been shown that satellite O3 retrievals are sensitive to a priori O3 profiles and covariance matrices. During this work we investigate the climatological data to be used in TEMPO algorithms (TB O3) and simulated data from the NASA GMAO Goddard Earth Observing System (GEOS-5) Forward Processing (FP) near-real-time (NRT) model products. These two data products will be evaluated with ground-based lidar data from the Tropospheric Ozone Lidar Network (TOLNet) at various locations of the US. This study evaluates the TB climatology, GEOS-5 climatology, and 3-hourly GEOS-5 data compared to lower tropospheric observations to demonstrate the accuracy of a priori information to potentially be used in TEMPO O3 algorithms. Here we present our initial analysis and the theoretical impact on TEMPO retrievals in the lower troposphere.

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

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......, 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. RESULTS: No differences of functional connectivity were found between patients...

The Vertical Structure of Relative Humidity and Ozone in the Tropical Upper Troposphere: Intercomparisons Among In Situ Observations, A-Train Measurements and Large-Scale Models

Science.gov (United States)

Selkirk, Henry B.; Manyin, Michael; Douglass, Anne R.; Oman, Luke; Pawson, Steven; Ott, Lesley; Benson, Craig; Stolarski, Richard

2010-01-01

In situ measurements in the tropics have shown that in regions of active convection, relative humidity with respect to ice in the upper troposphere is typically close to saturation on average, and supersaturations greater than 20% are not uncommon. Balloon soundings with the cryogenic frost point hygrometer (CFH) at Costa Rica during northern summer, for example, show this tendency to be strongest between 11 and 15.5 km (345-360 K potential temperature, or approximately 250-120 hPa). this is the altitude range of deep convective detrainment. Additionally, simultaneous ozonesonde measurements show that stratospheric air (O3 greater than 150 ppbv) can be found as low as approximately 14 km (350 K/150 hPa). In contrast, results from northern winter show a much drier upper troposphere and little penetration of stratospheric air below the tropopause at 17.5 km (approximately 383 K). We show that these results are consistent with in situ measurements from the Measurement of Ozone and water vapor by Airbus In-service airCraft (MOZAIC) program which samples a wider, though still limited, range of tropical locations. To generalize to the tropics as a whole, we compare our insitu results to data from two A-Train satellite instruments, the Atmospheric Infrared Sounder (AIRS) and the Microwave Limb Sounder (MLS) on the Aqua and Aura satellites respectively. Finally, we examine the vertical structure of water vapor, relative humidity and ozone in the NASA Goddard MERRA analysis, an assimilation dataset, and a new version of the GEOS CCM, a free-running chemistry-climate model. We demonstrate that conditional probability distributions of relative humidity and ozone are a sensitive diagnostic for assessing the representation of deep convection and upper troposphere/lower stratosphere mixing processes in large-scale analyses and climate models.

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

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...

Quantification of topographic venting of boundary layer air to the free troposphere

Directory of Open Access Journals (Sweden)

S. Henne

2004-01-01

Full Text Available Net vertical air mass export by thermally driven flows from the atmospheric boundary layer (ABL to the free troposphere (FT above deep Alpine valleys was investigated. The vertical export of pollutants above mountainous terrain is presently poorly represented in global chemistry transport models (GCTMs and needs to be quantified. Air mass budgets were calculated using aircraft observations obtained in deep Alpine valleys. The results show that on average 3 times the valley air mass is exported vertically per day under fair weather conditions. During daytime the type of valleys investigated in this study can act as an efficient 'air pump' that transports pollutants upward. The slope wind system within the valley plays an important role in redistributing pollutants. Nitrogen oxide emissions in mountainous regions are efficiently injected into the FT. This could enhance their ozone (O3 production efficiency and thus influences tropospheric pollution budgets. Once lifted to the FT above the Alps pollutants are transported horizontally by the synoptic flow and are subject to European pollution export. Forward trajectory studies show that under fair weather conditions two major pathways for air masses above the Alps dominate. Air masses moving north are mixed throughout the whole tropospheric column and further transported eastward towards Asia. Air masses moving south descend within the subtropical high pressure system above the Mediterranean.

Is There Evidence that Mid-Latitude Stratospheric Ozone Depletion Occurs in Conjunction with North American Monsoon Convection?

Science.gov (United States)

Rosenlof, K. H.; Ray, E. A.; Portmann, R. W.

2017-12-01

A recent study suggests that during the period of the summertime North American Monsoon (NAM), ozone depletion could occur as a result of catalytic ozone destruction associated with the cold and wet conditions caused by overshooting convection. Aura Microwave Limb Sounder (MLS) water vapor measurements do show that the NAM region is wetter than other parts of the globe in regards to both the mean and extremes. However, definitive evidence of ozone depletion occurring in that region has not been presented. In this study, we examine coincident measurements of water vapor, ozone, and tropospheric tracers from aircraft data taken during the Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) aircraft campaign looking specifically for ozone depletion in regions identified as impacted by overshooting convection. Although we do find evidence of lower ozone values in air impacted by convective overshoots, using tropospheric tracers we attribute those observations to input of tropospheric air rather than catalytic ozone destruction. Additionally, we explore the consequences of these lower ozone values on surface UV, and conclude that there is minimal impact on the UV index.

Elevated audiovisual temporal interaction in patients with migraine without aura

Science.gov (United States)

2014-01-01

Background Photophobia and phonophobia are the most prominent symptoms in patients with migraine without aura. Hypersensitivity to visual stimuli can lead to greater hypersensitivity to auditory stimuli, which suggests that the interaction between visual and auditory stimuli may play an important role in the pathogenesis of migraine. However, audiovisual temporal interactions in migraine have not been well studied. Therefore, our aim was to examine auditory and visual interactions in migraine. Methods In this study, visual, auditory, and audiovisual stimuli with different temporal intervals between the visual and auditory stimuli were randomly presented to the left or right hemispace. During this time, the participants were asked to respond promptly to target stimuli. We used cumulative distribution functions to analyze the response times as a measure of audiovisual integration. Results Our results showed that audiovisual integration was significantly elevated in the migraineurs compared with the normal controls (p audiovisual suppression was weaker in the migraineurs compared with the normal controls (p < 0.05). Conclusions Our findings further objectively support the notion that migraineurs without aura are hypersensitive to external visual and auditory stimuli. Our study offers a new quantitative and objective method to evaluate hypersensitivity to audio-visual stimuli in patients with migraine. PMID:24961903

Towards an Integrated Assessment Model for Tropospheric Ozone-Emission Inventories, Scenarios and Emission-control Options

OpenAIRE

Olsthoorn, X.

1994-01-01

IIASA intends to extend its RAINS model for addressing the issue of transboundary ozone air pollution. This requires the development of a VOC-emissions module, VOCs being precursors in ozone formation. The module should contain a Europe-wide emission inventory, a submodule for developing emission scenarios and a database of measures for VOC-emission control, including data about control effectiveness and control costs. It is recommended to use the forthcoming CORINAIR90 inventory for construc...

Worldwide biogenic soil NOx emissions inferred from OMI NO2 observations

NARCIS (Netherlands)

Vinken, G.C.M.; Boersma, K.F.; Maasakkers, J.D.; Adon, M.; Martin, R.V.

2014-01-01

Biogenic NOx emissions from soils are a large natural source with substantial uncertainties in global bottom-up estimates (ranging from 4 to 15 Tg N yr-1). We reduce this range in emission estimates, and present a top-down soil NOx emission inventory for 2005 based on retrieved tropospheric NO2

Worldwide biogenic soil NOx emissions inferred from OMI NO2 observations.

NARCIS (Netherlands)

Vinken, G.C.M.; Boersma, K.F.; Maasakkers, J.D.; Adon, M.; Martin, R.V.

2014-01-01

Biogenic NOx emissions from soils are a large natural source with substantial uncertainties in global bottom-up estimates (ranging from 4 to 15 Tg N yr-1). We reduce this range in emission estimates, and present a top-down soil NOx emission inventory for 2005 based on retrieved tropospheric NO2

HIRDLS/Aura Level 3 Extinction at 12.1 Microns Zonal Fourier Coefficients V007

Data.gov (United States)

National Aeronautics and Space Administration — The "HIRDLS/Aura Level 3 Extinction at 12.1 Microns Zonal Fourier Coefficients" version 7 data product (H3ZFC12MEXT) contains the entire mission (~3 years) of HIRDLS...

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.

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

Ten years of study has resulted in considerable but fragmented knowledge about regional cerebral blood flow in migraine with aura (classic migraine). In the present study, the number of repeatedly studied patients (n = 63) was large enough to determine statistically significant sequences of event...

Simplified Modeling of Tropospheric Ozone Formation Considering Alternative Fuels Using

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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.

Honey From Maggots: Aura, Sacrifice, and the Human Universe in Charles Olson's "The Kingfishers"

Science.gov (United States)

Roethle, Christopher James

In this thesis, I contend that some form of aura can be recovered from the ravages of technological reproduction described in Walter Benjamin's "The Work of Art in the Age of its Technological Reproducibility (Third Version)." Recovering this aura, however, may require adopting an aesthetic of immediacy through destruction and even wanton disposability (what Georges Bataille in his general economic theory calls "nonproductive expenditure") to ensure that, though routinely diluted and discarded, the split-second authenticity of a work remains, its radical ephemerality and formal irreproducibility opposing the enslaving, commodifying powers of the copy. The poetry and poetic theory of American poet Charles Olson, especially in his long poem "The Kingfishers" and his essays "Projective Verse" and "Human Universe," serves as an example of how an author might inscribe auratic energy along nonproductive, general economic lines.

Diurnal Variation in the Basal Emission Rate of Isoprene

Science.gov (United States)

Jennifer Funk; Clive G. Jones; Christine J. Baker; Heather M. Fuller; Christian P. Giardina; Manuel T. Lerdua

2003-01-01

Isoprene is emitted from numerous plant species and profoundly influences tropospheric chemistry. Due to the short lifetime of isoprene in the atmosphere, developing an understanding of emission patterns at small time scales is essential for modeling regional atmospheric chemistry processes. Previous studies suggest that diurnal fluctuations in isoprene emission may be...

Tropospheric Halogen Chemistry

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von Glasow, R.; Crutzen, P. J.

2003-12-01

compilations of laboratory studies that were made to elucidate chemical reaction paths are given by, e.g., DeMore et al. (1997), Sander et al. (2000), and Atkinson et al. (1999, 2000). Emission inventories for chlorine were compiled by Graedel and Keene (1995) and Keene et al. (1999).In Section 4.02.2 of this overview we will first describe the main halogen reaction mechanisms and then discuss, in Section 4.02.3, the springtime surface ozone depletion events in high latitudes that were first observed in the Arctic. Another main part of this chapter is concerned with halogens in the marine boundary layer ( Section 4.02.4). In Section 4.02.5 we describe interactions of halogens with some other elements of atmospheric importance. A very recently discovered environment where halogen chemistry plays a large role are salt lakes ( Section 4.02.6). There the chemistry bears similarity to that of the high-latitude ozone depletion events. This is followed in Section 4.02.7 by a discussion of halogen chemistry in the free troposphere and in Section 4.02.8 by other sources of halogens such as industry and biomass burning.

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

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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

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.

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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. © 2013.

Tropospheric chemistry of natural hydrocarbons, aldehydes, and peroxy radicals: Their connections to sulfuric acid production and climate effects

International Nuclear Information System (INIS)

Gaffney, J.S.; Marley, N.A.

1993-05-01

Recent work has shown that natural hydrocarbon emissions can significantly affect the levels of urban and regional tropospheric ozone. We report on the reactivities of these biogenic trace gases, particularly isoprene, focusing on their importance in the production of aldehydes and peroxy radicals, leading to increased levels of hydrogen over regional forests. Hydrogen peroxide can lead to the wet oxidation of sulfur dioxide to acidic sulfate in aerosols, fogs, and clouds. In turn, acidic sulfate can act to as a light scattering aerosol and a source of cloud condensation nuclei (CCN), potentially leading to global cooling. Aerosol sulfate and other dissolved organic and inorganic compounds can also play important roles as a greenhouse species in the lower troposphere

Savanna burning and convective mixing in Southern Africa: Implications for CO emissions and transport

International Nuclear Information System (INIS)

Connors, V.S.; Cahoon, D.R. Jr.; Reichle, H.G. Jr.; Brunke, E.G.; Garstang, M.; Seiler, W.; Scheel, H.E.

1991-01-01

This study examines both the emission and the transport of CO from the surface to the free troposphere and the role of convection in redistributing this gas in the free troposphere over southern Africa. Upper-air soundings, the meteorological analyses from the European Center for Medium-Range Weather Forecasts (ECMWF), and the multispectral imagery from the European Space Agency's Meteosat-2 satellite comprise the meteorological data base. The surface measurements of CO were measured at an atmospheric chemistry laboratory in Cape Point, South Africa. The CO in the middle troposphere was measured by the Measurement of Air Pollution from Satellites (MAPS) experiment flown on the space shuttle. This study focuses on the emissions and transport of CO from Africa south of the equator on 5-6 October 1984

Observations of peroxyacetyl nitrate (PAN) in the upper troposphere by the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS)

Science.gov (United States)

Tereszchuk, K. A.; Moore, D. P.; Harrison, J. J.; Boone, C. D.; Park, M.; Remedios, J. J.; Randel, W. J.; Bernath, P. F.

2013-01-01

principal source of PAN in the UTLS is due to lofted biomass burning emissions from the pyroconvective updrafts created by large fires, the observed seasonality in enhanced PAN coincides with fire activity in different geographical regions throughout the year. This work is part of an in-depth investigation that is being conducted in an effort to study the aging and chemical evolution of biomass burning emissions in the UTLS by remote, space-borne measurements made by ACE-FTS to further our understanding of the impact of pyrogenic emissions on atmospheric chemistry. Included in this study will be the addition of new, pyrogenic, volatile organic hydrocarbons (VOCs) and oxygenated volatile organic compounds (OVOCs) to expand upon the already extensive suite of molecules retrieved by ACE-FTS to aid in elucidating biomass burning plume chemistry in the free troposphere.

The Global Structure of UTLS Ozone in GEOS-5: A Multi-Year Assimilation of EOS Aura Data

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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.

Free-tropospheric BrO investigations based on GOME

Science.gov (United States)

Post, P.; van Roozendael, M.; Backman, L.; Damski, J.; Thölix, L.; Fayt, C.; Taalas, P.

2003-04-01

Bromine compounds contribute significantly to the stratospheric ozone depletion. However measurements of most bromine compounds are sparse or non-existent, and experimental studies essentially rely on BrO observations. The differences between balloon and ground based measurements of stratospheric BrO columns and satellite total column measurements are too large to be explained by measurement uncertainties. Therefore, it has been assumed that there is a concentration of BrO in the free troposphere of about 1-3 ppt. In a previous work, we have calculated the tropospheric BrO abundance as the difference between total BrO and stratospheric BrO columns. The total vertical column densities of BrO are extracted from GOME measurements using IASB-BIRA algorithms. The stratospheric amount has been calculated using chemical transport models (CTM). Results from SLIMCAT and FinROSE simulations are used for this purpose. SLIMCAT is a widely used 3D CTM that has been tested against balloon measurements. FinROSE is a 3D CTM developed at FMI. We have tried several different tropospheric BrO profiles. Our results show that a profile with high BrO concentrations in the boundary layer usually gives unrealistically high tropospheric column values over areas of low albedo (like oceans). This suggests that the tropospheric BrO would be predominantly distributed in the free troposphere. In this work, attempts are made to identify the signature of a free tropospheric BrO content when comparing cloudy and non-cloudy scenes. The possible impact of orography on measured BrO columns is also investigated.

Performance analysis of NOAA tropospheric signal delay model

International Nuclear Information System (INIS)

Ibrahim, Hassan E; El-Rabbany, Ahmed

2011-01-01

Tropospheric delay is one of the dominant global positioning system (GPS) errors, which degrades the positioning accuracy. Recent development in tropospheric modeling relies on implementation of more accurate numerical weather prediction (NWP) models. In North America one of the NWP-based tropospheric correction models is the NOAA Tropospheric Signal Delay Model (NOAATrop), which was developed by the US National Oceanic and Atmospheric Administration (NOAA). Because of its potential to improve the GPS positioning accuracy, the NOAATrop model became the focus of many researchers. In this paper, we analyzed the performance of the NOAATrop model and examined its effect on ionosphere-free-based precise point positioning (PPP) solution. We generated 3 year long tropospheric zenith total delay (ZTD) data series for the NOAATrop model, Hopfield model, and the International GNSS Services (IGS) final tropospheric correction product, respectively. These data sets were generated at ten IGS reference stations spanning Canada and the United States. We analyzed the NOAATrop ZTD data series and compared them with those of the Hopfield model. The IGS final tropospheric product was used as a reference. The analysis shows that the performance of the NOAATrop model is a function of both season (time of the year) and geographical location. However, its performance was superior to the Hopfield model in all cases. We further investigated the effect of implementing the NOAATrop model on the ionosphere-free-based PPP solution convergence and accuracy. It is shown that the use of the NOAATrop model improved the PPP solution convergence by 1%, 10% and 15% for the latitude, longitude and height components, respectively

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

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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.

Characterization of pollution in the arctic troposphere: use of airborne and satellite data as part of the IPY/POLARCAT campaign

International Nuclear Information System (INIS)

Pommier, M.

2011-01-01

Despite improvements in observing systems and numerical models in recent decades, it remains difficult to reproduce the observed pollution episodes in the Arctic especially in summertime. One possible explanation is the underestimation of modelled ozone (O 3 ) production in forest fires plumes. Carbon monoxide (CO) is often used as a tracer of pollution transport due to its relatively long lifetime of several weeks in the troposphere. It is a reactive gas, mainly produced by the combustion of fossil fuels and vegetation burning. Moreover, since its main sink is reaction with OH radical, CO has an important role in the oxidizing power of the atmosphere it also plays an important role in the assessment of tropospheric ozone. The purpose of my thesis has been to contribute to a better understanding of transport and of the chemical mechanisms of pollutants formation in the Arctic troposphere. A combination of the new CO measurements from the IASI satellite instrument, launched in October 2006 aboard the MetOp-A and aircraft data collected during the POLARCAT campaigns of the International Polar Year, in spring and summer 2008 were used. IASI CO observations were first validated by comparison with in situ airborne measurements showing its ability to detect the evolution of high CO signatures plume as close to sources regions. The second part of the thesis used assimilation of daily IASI CO measurements (Kalman filter) in the LMDz-INCA global model to improve our understanding about sources of pollution impacting the Arctic troposphere and their transport pathways. The assimilation has improved the modelling of CO pollution episodes in the Arctic free troposphere. Model results were also evaluated using POLARCAT observations and used to examine the sensitivity of Arctic pollutant concentrations (namely the overestimation of O 3 distribution and the underestimation of peroxy acetyl nitride - PAN - distribution) to emissions from different regions and in particular the

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.

Efficient transport of tropospheric aerosol into the stratosphere via the Asian summer monsoon anticyclone

Science.gov (United States)

Yu, Pengfei; Rosenlof, Karen H.; Liu, Shang; Telg, Hagen; Thornberry, Troy D.; Rollins, Andrew W.; Portmann, Robert W.; Bai, Zhixuan; Ray, Eric A.; Duan, Yunjun; Pan, Laura L.; Toon, Owen B.; Bian, Jianchun; Gao, Ru-Shan

2017-07-01

An enhanced aerosol layer near the tropopause over Asia during the June-September period of the Asian summer monsoon (ASM) was recently identified using satellite observations. Its sources and climate impact are presently not well-characterized. To improve understanding of this phenomenon, we made in situ aerosol measurements during summer 2015 from Kunming, China, then followed with a modeling study to assess the global significance. The in situ measurements revealed a robust enhancement in aerosol concentration that extended up to 2 km above the tropopause. A climate model simulation demonstrates that the abundant anthropogenic aerosol precursor emissions from Asia coupled with rapid vertical transport associated with monsoon convection leads to significant particle formation in the upper troposphere within the ASM anticyclone. These particles subsequently spread throughout the entire Northern Hemispheric (NH) lower stratosphere and contribute significantly (˜15%) to the NH stratospheric column aerosol surface area on an annual basis. This contribution is comparable to that from the sum of small volcanic eruptions in the period between 2000 and 2015. Although the ASM contribution is smaller than that from tropical upwelling (˜35%), we find that this region is about three times as efficient per unit area and time in populating the NH stratosphere with aerosol. With a substantial amount of organic and sulfur emissions in Asia, the ASM anticyclone serves as an efficient smokestack venting aerosols to the upper troposphere and lower stratosphere. As economic growth continues in Asia, the relative importance of Asian emissions to stratospheric aerosol is likely to increase.

Anatomical alterations of the visual motion processing network in migraine with and without aura.

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Cristina Granziera

2006-10-01

Full Text Available Patients suffering from migraine with aura (MWA and migraine without aura (MWoA show abnormalities in visual motion perception during and between attacks. Whether this represents the consequences of structural changes in motion-processing networks in migraineurs is unknown. Moreover, the diagnosis of migraine relies on patient's history, and finding differences in the brain of migraineurs might help to contribute to basic research aimed at better understanding the pathophysiology of migraine.To investigate a common potential anatomical basis for these disturbances, we used high-resolution cortical thickness measurement and diffusion tensor imaging (DTI to examine the motion-processing network in 24 migraine patients (12 with MWA and 12 MWoA and 15 age-matched healthy controls (HCs. We found increased cortical thickness of motion-processing visual areas MT+ and V3A in migraineurs compared to HCs. Cortical thickness increases were accompanied by abnormalities of the subjacent white matter. In addition, DTI revealed that migraineurs have alterations in superior colliculus and the lateral geniculate nucleus, which are also involved in visual processing.A structural abnormality in the network of motion-processing areas could account for, or be the result of, the cortical hyperexcitability observed in migraineurs. The finding in patients with both MWA and MWoA of thickness abnormalities in area V3A, previously described as a source in spreading changes involved in visual aura, raises the question as to whether a "silent" cortical spreading depression develops as well in MWoA. In addition, these experimental data may provide clinicians and researchers with a noninvasively acquirable migraine biomarker.

Importance of Rain Evaporation and Continental Convection in the Tropical Water Cycle

Science.gov (United States)

Worden, John; Noone, David; Bowman, Kevin; Beer, R.; Eldering, A.; Fisher, B.; Gunson, M.; Goldman, Aaron; Kulawik, S. S.; Lampel, Michael;

Performance Evaluation of Blind Tropospheric Delay correction ...

African Journals Online (AJOL)

lekky

and Temperature 2 wet (GPT2w) models) for tropospheric delay correction, ... In practice, a user often employs a certain troposphere model based on the popularity ... comparisons between some of the models have been carried out in the past for .... prediction of meteorological parameter values, which are then used to ...

Infrared Solar Spectroscopic Measurements of Free Tropospheric CO, C2H6, and HCN above Mauna Loa, Hawaii: Seasonal Variations and Evidence for Enhanced Emissions from the Southeast Asian Tropical Fires of 1997-1998

Science.gov (United States)

Rinsland, C. P.; Goldman, A.; Murcray, F. J.; Stephen, T. M.; Pougatchev, N. S.; Fishman, J.; David, S. J.; Blatherwick, R. D.; Novelli, P. C.; Jones, N. B.

1999-01-01

High spectral resolution (0.003 per cm) infrared solar absorption measurements of CO, C2H6, and HCN have been recorded at the Network for the Detection of Stratospheric Change station on Mauna Loa, Hawaii, (19.5N, 155.6W, altitude 3.4 km). The observations were obtained on over 250 days between August 1995 and February 1998. Column measurements are reported for the 3.4-16 km altitude region, which corresponds approximately to the free troposphere above the station. Average CO mixing ratios computed for this layer have been compared with flask sampling CO measurements obtained in situ at the station during the same time period. Both show asymmetrical seasonal cycles superimposed on significant variability. The first 2 years of observations exhibit a broad January-April maximum and a sharper CO minimum during late summer. The C2H6 and CO 3.4-16 km columns were highly correlated throughout the observing period with the C2H6/CO slope intermediate between higher and lower values derived from similar infrared spectroscopic measurements at 32'N and 45'S latitude, respectively. Variable enhancements in CO, C2H6, and particularly HCN were observed beginning in about September 1997. The maximum HCN free tropospheric monthly mean column observed in November 1997 corresponds to an average 3.4-16 km mixing ratio of 0.7 ppbv (1 ppbv = 10(exp -9) per unit volume), more than a factor of 3 above the background level. The HCN enhancements continued through the end of the observational series. Back-trajectory calculations suggest that the emissions originated at low northern latitudes in southeast Asia. Surface CO mixing ratios and the C2H6 tropospheric columns measured during the same time also showed anomalous autumn 1997 maxima. The intense and widespread tropical wild fires that burned during the strong El Nino warm phase of 1997- 1998 are the likely source of the elevated emission products.

The NOx Budget. Market-based control of tropospheric ozone in the northeastern United States

International Nuclear Information System (INIS)

Farrell, Alex; Carter, Robert; Raufer, Roger

1999-01-01

The NOx Budget is a marketable emissions allowance system currently being adopted by states in the Northeastern US to reduce tropospheric ozone concentrations to healthful levels in a cost-effective manner. Oxides of nitrogen (NOx) are currently regulated within the existing Command and Control (CAC) framework. The introduction of a market-based approach will further reduce emissions, but will not resolve all regulatory uncertainties. These implementation concerns are identified and discussed. Cost savings and emissions reductions patterns which will arise under several different scenarios are determined through the use of a dynamic, relaxed mixed-integer linear programming model of the NOx allowance market. Like other market-based pollution control programs, the NOx Budget is found to be more efficient than CAC options. Restrictions on the market designed to address perceived flaws are found to be expensive but ineffectual

Estimation of biogenic volatile organic compounds emissions in subtropical island--Taiwan.

Science.gov (United States)

Chang, Ken-Hui; Chen, Tu-Fu; Huang, Ho-Chun

2005-06-15

Elevated tropospheric ozone is harmful to human health and plants. It is formed through the photochemical reactions involving volatile organic compounds (VOCs) and nitrogen oxides (NO(x)). The elevated ozone episodes occur mainly in summer months in the United States, while the high-ozone episodes frequently occur during the fall in Taiwan. The unique landscape of Taiwan produces tremendous amounts of biogenic VOCs in the mountain regions that are adjacent to concentrated urban areas. The urban areas, in turn, generate prodigious amounts of anthropogenic emissions. Biogenic VOC emissions have direct influence on tropospheric ozone formation. To explore the air quality problems in Taiwan, this study attempts to develop a biogenic VOC emission model suitable for air quality applications in Taiwan. The emission model is based on the Biogenic Emissions Inventory System Version 2 and coupled with a detailed Taiwan land use database. The 1999 total Taiwan biogenic VOC emissions were estimated at 214,000 metric tons. The emissions of isoprene, monoterpenes, and other VOCs were about 37.2%, 30.4%, and 32.4% of total biogenic VOC emissions, respectively. The annual total biogenic VOC emission per unit area was more than two times the value of that in any European country, implying that detailed emissions estimates in any size of region will benefit the global biogenic emission inventories.

Análise da camada de fibras nervosas da retina em portadores de enxaqueca com aura Retinal nerve fiber layer measurements in patients with migraine with aura

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Felipe Andrade Medeiros

2001-10-01

Full Text Available Objetivo: Avaliar as possíveis alterações na camada de fibras nervosas da retina (CFNR em pacientes com enxaqueca com aura, detectada por meio da polarimetria de varredura a laser. Métodos: Vinte pacientes com enxaqueca com aura e vinte indivíduos normais foram estudados. Os critérios de inclusão para os dois grupos compreenderam: idade de pelo menos 18 anos; ausência de história de doenças oculares, exceto erro refracional ou estrabismo; e ausência de história familiar de hipertensão ocular ou glaucoma. Foram excluídos pacientes com erro refracional maior que 5 DE e/ou 2 DC; acuidade visual corrigida menor que 20/40; pressão intra-ocular maior que 21 mmHg; discos ópticos anômalos ou com escavação maior que 0,5 ou assimetria de escavação maior que 0,2; ou com presença de doenças retinianas concomitantes. Os pacientes foram submetidos a exame de campo visual (Humphrey 30-2 e análise da CFNR com a polarimetria a laser (GDx - Nerve Fiber Analyzer. Um olho de cada paciente foi randomizado para análise estatística. Resultados: Nenhum dos pacientes do grupo controle apresentou defeitos de campo visual. Nove olhos (45% dos pacientes com enxaqueca tiveram anormalidades de campo visual além de 95% do intervalo de confiança do normal, como indicado pelos índices MD, CPSD ou GHT. Os valores de retardo no setor superior da CFNR dos pacientes com enxaqueca foram significativamente menor que no grupo controle (p=0,005. Não houve diferença significativa entre os valores de retardo dos dois grupos nas medidas globais e nos setores inferior, nasal e temporal. Conclusão: As medidas de retardo obtidas com a polarimetria a laser foram significativamente menores na porção superior da CFNR dos pacientes com enxaqueca com aura, sugerindo possível dano isquêmico às fibras nervosas, relacionadas à enxaqueca.Purpose: To evaluate the possible alterations of the retinal nerve fiber layer (RNFL, as detected by scanning laser polarimetry

Long-term changes in lower tropospheric baseline ozone concentrations: Comparing chemistry-climate models and observations at northern midlatitudes

Science.gov (United States)

Parrish, D. D.; Lamarque, J.-F.; Naik, V.; Horowitz, L.; Shindell, D. T.; Staehelin, J.; Derwent, R.; Cooper, O. R.; Tanimoto, H.; Volz-Thomas, A.; Gilge, S.; Scheel, H.-E.; Steinbacher, M.; Fröhlich, M.

2014-05-01

Two recent papers have quantified long-term ozone (O3) changes observed at northern midlatitude sites that are believed to represent baseline (here understood as representative of continental to hemispheric scales) conditions. Three chemistry-climate models (NCAR CAM-chem, GFDL-CM3, and GISS-E2-R) have calculated retrospective tropospheric O3 concentrations as part of the Atmospheric Chemistry and Climate Model Intercomparison Project and Coupled Model Intercomparison Project Phase 5 model intercomparisons. We present an approach for quantitative comparisons of model results with measurements for seasonally averaged O3 concentrations. There is considerable qualitative agreement between the measurements and the models, but there are also substantial and consistent quantitative disagreements. Most notably, models (1) overestimate absolute O3 mixing ratios, on average by 5 to 17 ppbv in the year 2000, (2) capture only 50% of O3 changes observed over the past five to six decades, and little of observed seasonal differences, and (3) capture 25 to 45% of the rate of change of the long-term changes. These disagreements are significant enough to indicate that only limited confidence can be placed on estimates of present-day radiative forcing of tropospheric O3 derived from modeled historic concentration changes and on predicted future O3 concentrations. Evidently our understanding of tropospheric O3, or the incorporation of chemistry and transport processes into current chemical climate models, is incomplete. Modeled O3 trends approximately parallel estimated trends in anthropogenic emissions of NOx, an important O3 precursor, while measured O3 changes increase more rapidly than these emission estimates.

Sulfate Aerosols from Non-Explosive Volcanoes: Chemical-Radiative Effects in the Troposphere and Lower Stratosphere

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Giovanni Pitari

2016-06-01

Full Text Available SO2 and H2S are the two most important gas-phase sulfur species emitted by volcanoes, with a global amount from non-explosive emissions of the order 10 Tg-S/yr. These gases are readily oxidized forming SO42− aerosols, which effectively scatter the incoming solar radiation and cool the surface. They also perturb atmospheric chemistry by enhancing the NOx to HNO3 heterogeneous conversion via hydrolysis on the aerosol surface of N2O5 and Br-Cl nitrates. This reduces formation of tropospheric O3 and the OH to HO2 ratio, thus limiting the oxidation of CH4 and increasing its lifetime. In addition to this tropospheric chemistry perturbation, there is also an impact on the NOx heterogeneous chemistry in the lower stratosphere, due to vertical transport of volcanic SO2 up to the tropical tropopause layer. Furthermore, the stratospheric O3 formation and loss, as well as the NOx budget, may be slightly affected by the additional amount of upward diffused solar radiation and consequent increase of photolysis rates. Two multi-decadal time-slice runs of a climate-chemistry-aerosol model have been designed for studying these chemical-radiative effects. A tropopause mean global net radiative flux change (RF of −0.23 W·m−2 is calculated (including direct and indirect aerosol effects with a 14% increase of the global mean sulfate aerosol optical depth. A 5–15 ppt NOx decrease is found in the mid-troposphere subtropics and mid-latitudes and also from pole to pole in the lower stratosphere. The tropospheric NOx perturbation triggers a column O3 decrease of 0.5–1.5 DU and a 1.1% increase of the CH4 lifetime. The surface cooling induced by solar radiation scattering by the volcanic aerosols induces a tropospheric stabilization with reduced updraft velocities that produce ice supersaturation conditions in the upper troposphere. A global mean 0.9% decrease of the cirrus ice optical depth is calculated with an indirect RF of −0.08 W·m−2.

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,...

On the capability of IASI measurements to inform about CO surface emissions

Directory of Open Access Journals (Sweden)

S. Szopa

2009-11-01

Full Text Available Between July and November 2008, simultaneous observations were conducted by several orbiting instruments that monitor carbon monoxide in the atmosphere, among them the Infrared Atmospheric Sounding Instrument (IASI and Measurements Of Pollution In The Troposphere (MOPITT. In this paper, the concentration retrievals at about 700 hPa from these two instruments are successively used in a variational Bayesian system to infer the global distribution of CO emissions. Starting from a global emission budget of 479 Tg for the considered period, the posterior estimate of CO emissions using IASI retrievals gives a total of 643 Tg, which is in close agreement with the budget calculated with version 3 of the MOPITT data (649 Tg. The regional totals are also broadly consistent between the two inversions. Even though our theoretical error budget indicates that IASI constrains the emissions slightly less than MOPITT, because of lesser sensitivity in the lower troposphere, these first results indicate that IASI may play a major role in the quantification of the emissions of CO.

Interactive chemistry in the Laboratoire de Météorologie Dynamique general circulation model: model description and impact analysis of biogenic hydrocarbons on tropospheric chemistry

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G. A. Folberth

2006-01-01

Full Text Available We present a description and evaluation of LMDz-INCA, a global three-dimensional chemistry-climate model, pertaining to its recently developed NMHC version. In this substantially extended version of the model a comprehensive representation of the photochemistry of non-methane hydrocarbons (NMHC and volatile organic compounds (VOC from biogenic, anthropogenic, and biomass-burning sources has been included. The tropospheric annual mean methane (9.2 years and methylchloroform (5.5 years chemical lifetimes are well within the range of previous modelling studies and are in excellent agreement with estimates established by means of global observations. The model provides a reasonable simulation of the horizontal and vertical distribution and seasonal cycle of CO and key non-methane VOC, such as acetone, methanol, and formaldehyde as compared to observational data from several ground stations and aircraft campaigns. LMDz-INCA in the NMHC version reproduces tropospheric ozone concentrations fairly well throughout most of the troposphere. The model is applied in several sensitivity studies of the biosphere-atmosphere photochemical feedback. The impact of surface emissions of isoprene, acetone, and methanol is studied. These experiments show a substantial impact of isoprene on tropospheric ozone and carbon monoxide concentrations revealing an increase in surface O3 and CO levels of up to 30 ppbv and 60 ppbv, respectively. Isoprene also appears to significantly impact the global OH distribution resulting in a decrease of the global mean tropospheric OH concentration by approximately 0.7×105 molecules cm-3 or roughly 8% and an increase in the global mean tropospheric methane lifetime by approximately seven months. A global mean ozone net radiative forcing due to the isoprene induced increase in the tropospheric ozone burden of 0.09 W m-2 is found. The key role of isoprene photooxidation in the global tropospheric redistribution of NOx is demonstrated. LMDz

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

2016-09-08

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.

Spatio-temporal variability of CO and O3 in Hyderabad (17°N, 78°E, central India, based on MOZAIC and TES observations and WRF-Chem and MOZART-4 models

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Varun Sheel

2016-05-01

Full Text Available This article is based on the study of the seasonal and interannual variability of carbon monoxide (CO and ozone (O3 at different altitudes of the troposphere over Hyderabad, India, during 2006–2010 using Measurement of OZone and water vapour by Airbus In-Service Aircraft (MOZAIC and observation from Tropospheric Emission Spectrometer (TES aboard NASA's Aura satellite. The MOZAIC observations show maximum seasonal variability in both CO and O3 during winter and pre-monsoon season, with CO in the range (100–200±13 ppbv and O3 in the range (50–70±9 ppbv. The time-series of MOZAIC data shows a significant increase of 4.2±1.3 % in the surface CO and 6.7±1.3 % in the surface O3 during 2006–2010 in Hyderabad. From MOZAIC observations, we identify CO and O3 profiles that are anomalous with respect to the monthly mean and compare those with Weather Research Forecast model coupled with Chemistry (WRF-Chem and Model for OZone and Related Tracers, version 4 profiles for the same day. The anomalous profiles of WRF-Chem are simulated using three convection schemes. The goodness of comparison depends on the convection scheme and the altitude region of the troposphere.

Using Satellite Remote Sensing and Modelling for Insights into N02 Air Pollution and NO2 Emissions

Science.gov (United States)

Lamsal, L. N.; Martin, R. V.; Krotkov, N. A.; Bucsela, E. J.; Celarier, E. A.; vanDonkelaar, A.; Parrish, D.

2012-01-01

Nitrogen oxides (NO(x)) are key actors in air quality and climate change. Satellite remote sensing of tropospheric NO2 has developed rapidly with enhanced spatial and temporal resolution since initial observations in 1995. We have developed an improved algorithm and retrieved tropospheric NO2 columns from Ozone Monitoring Instrument. Column observations of tropospheric NO2 from the nadir-viewing satellite sensors contain large contributions from the boundary layer due to strong enhancement of NO2 in the boundary layer. We infer ground-level NO2 concentrations from the OMI satellite instrument which demonstrate significant agreement with in-situ surface measurements. We examine how NO2 columns measured by satellite, ground-level NO2 derived from satellite, and NO(x) emissions obtained from bottom-up inventories relate to world's urban population. We perform inverse modeling analysis of NO2 measurements from OMI to estimate "top-down" surface NO(x) emissions, which are used to evaluate and improve "bottom-up" emission inventories. We use NO2 column observations from OMI and the relationship between NO2 columns and NO(x) emissions from a GEOS-Chem model simulation to estimate the annual change in bottom-up NO(x) emissions. The emission updates offer an improved estimate of NO(x) that are critical to our understanding of air quality, acid deposition, and climate change.

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.

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.

Magnetic resonance image abnormality in migraine with aura

International Nuclear Information System (INIS)

Ziegler, D.K.; Batnitzky, S.; Barter, R.; McMillan, J.H.

1991-01-01

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

The role of chemistry in under-predictions of NO2 in the upper troposphere

Science.gov (United States)

Henderson, B. H.; Pinder, R. W.; Goliff, W. S.; Stockwell, W. R.; Fahr, A.; Sarwar, G.; Hutzell, W. T.; Mathur, R.; Vizuete, W.; Cohen, R. C.

2009-12-01

Global and regional atmospheric models under-predict upper troposphere NO2 compared to satellite and aircraft observations. The upper tropospheric under-prediction of NO2 could be a function of emissions, transport, chemistry or some combination. Previous researchers have linked poor performance in the model to over-prediction of the OH and under-prediction of the HO2 by chemistry (Olson et al. 2006, Bertram et al. 2007). This study isolates upper tropospheric chemistry to evaluate the chemical contribution to NO2 under-predictions and to diagnose OH and HO2 discrepancies. We use a 0-dimensional time dependent model to evaluate seven chemical mechanisms. Because chamber data representing upper tropospheric conditions does not exist, we evaluate the predictions based against an observation-based aging model. Following Bertram et al (2007), we use the NOx:HNO3 ratio to categorize the chemical age of thousands of 10 second average observations between 8 and 10km. Measurements of 10 inorganics and 32 hydrocarbons are translated to model species for each of seven chemical mechanisms. We chose mechanisms ranging from condensed to semi-explicit. The seven mechanisms' design scopes range from urban to global scale. Results include simulations from Model for OZone And Related chemical Tracers (MOZART), Carbon Bond 05 (CB05), State Air Pollution Research Center (SAPRC) 99, SAPRC 07, GEOS-Chem, Regional Atmospheric Chemical Mechanism version 2, and the LEEDS Master Chemical Mechanism. Results from each chemical mechanism are compared to aircraft observations and to those obtained with other chemical mechanisms. Each mechanism is then further evaluated using integrated reaction rate analysis to identify sources of NO2 bias. We find that the largest contributors to the NO2 bias are over-predictions of PAN and HNO3. The formation of PAN is sensitive to the acetone photolysis rate. The conversion of NOx to HNO3 is most sensitive to hydroxyl radical concentrations. Hydroxyl

Iodine's impact on tropospheric oxidants: a global model study in GEOS-Chem

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T. Sherwen

2016-02-01

Full Text Available We present a global simulation of tropospheric iodine chemistry within the GEOS-Chem chemical transport model. This includes organic and inorganic iodine sources, standard gas-phase iodine chemistry, and simplified higher iodine oxide (I2OX, X = 2, 3, 4 chemistry, photolysis, deposition, and parametrized heterogeneous reactions. In comparisons with recent iodine oxide (IO observations, the simulation shows an average bias of  ∼ +90 % with available surface observations in the marine boundary layer (outside of polar regions, and of  ∼ +73 % within the free troposphere (350 hPa  <  p  <  900 hPa over the eastern Pacific. Iodine emissions (3.8 Tg yr−1 are overwhelmingly dominated by the inorganic ocean source, with 76 % of this emission from hypoiodous acid (HOI. HOI is also found to be the dominant iodine species in terms of global tropospheric IY burden (contributing up to 70 %. The iodine chemistry leads to a significant global tropospheric O3 burden decrease (9.0 % compared to standard GEOS-Chem (v9-2. The iodine-driven OX loss rate1 (748 Tg OX yr−1 is due to photolysis of HOI (78 %, photolysis of OIO (21 %, and reaction between IO and BrO (1 %. Increases in global mean OH concentrations (1.8 % by increased conversion of hydroperoxy radicals exceeds the decrease in OH primary production from the reduced O3 concentration. We perform sensitivity studies on a range of parameters and conclude that the simulation is sensitive to choices in parametrization of heterogeneous uptake, ocean surface iodide, and I2OX (X = 2, 3, 4 photolysis. The new iodine chemistry combines with previously implemented bromine chemistry to yield a total bromine- and iodine-driven tropospheric O3 burden decrease of 14.4 % compared to a simulation without iodine and bromine chemistry in the model, and a small increase in OH (1.8 %. This is a significant impact and so halogen chemistry needs to be

Global budget of tropospheric ozone: Evaluating recent model advances with satellite (OMI), aircraft (IAGOS), and ozonesonde observations

Science.gov (United States)

Hu, Lu; Jacob, Daniel J.; Liu, Xiong; Zhang, Yi; Zhang, Lin; Kim, Patrick S.; Sulprizio, Melissa P.; Yantosca, Robert M.

2017-10-01

The global budget of tropospheric ozone is governed by a complicated ensemble of coupled chemical and dynamical processes. Simulation of tropospheric ozone has been a major focus of the GEOS-Chem chemical transport model (CTM) over the past 20 years, and many developments over the years have affected the model representation of the ozone budget. Here we conduct a comprehensive evaluation of the standard version of GEOS-Chem (v10-01) with ozone observations from ozonesondes, the OMI satellite instrument, and MOZAIC-IAGOS commercial aircraft for 2012-2013. Global validation of the OMI 700-400 hPa data with ozonesondes shows that OMI maintained persistent high quality and no significant drift over the 2006-2013 period. GEOS-Chem shows no significant seasonal or latitudinal bias relative to OMI and strong correlations in all seasons on the 2° × 2.5° horizontal scale (r = 0.88-0.95), improving on previous model versions. The most pronounced model bias revealed by ozonesondes and MOZAIC-IAGOS is at high northern latitudes in winter-spring where the model is 10-20 ppbv too low. This appears to be due to insufficient stratosphere-troposphere exchange (STE). Model updates to lightning NOx, Asian anthropogenic emissions, bromine chemistry, isoprene chemistry, and meteorological fields over the past decade have overall led to gradual increase in the simulated global tropospheric ozone burden and more active ozone production and loss. From simulations with different versions of GEOS meteorological fields we find that tropospheric ozone in GEOS-Chem v10-01 has a global production rate of 4960-5530 Tg a-1, lifetime of 20.9-24.2 days, burden of 345-357 Tg, and STE of 325-492 Tg a-1. Change in the intensity of tropical deep convection between these different meteorological fields is a major factor driving differences in the ozone budget.

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

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

MLS/Aura Level 2 Hypochlorous Acid (HOCl) Mixing Ratio V003 (ML2HOCL) at GES DISC

Data.gov (United States)

National Aeronautics and Space Administration — ML2HOCL is the EOS Aura Microwave Limb Sounder (MLS) standard product for hypochlorous acid derived from radiances measured primarily by the 640 GHz radiometer. The...

Impact of selected troposphere models on Precise Point Positioning convergence

Science.gov (United States)

Kalita, Jakub; Rzepecka, Zofia

2016-04-01

The Precise Point Positioning (PPP) absolute method is currently intensively investigated in order to reach fast convergence time. Among various sources that influence the convergence of the PPP, the tropospheric delay is one of the most important. Numerous models of tropospheric delay are developed and applied to PPP processing. However, with rare exceptions, the quality of those models does not allow fixing the zenith path delay tropospheric parameter, leaving difference between nominal and final value to the estimation process. Here we present comparison of several PPP result sets, each of which based on different troposphere model. The respective nominal values are adopted from models: VMF1, GPT2w, MOPS and ZERO-WET. The PPP solution admitted as reference is based on the final troposphere product from the International GNSS Service (IGS). The VMF1 mapping function was used for all processing variants in order to provide capability to compare impact of applied nominal values. The worst case initiates zenith wet delay with zero value (ZERO-WET). Impact from all possible models for tropospheric nominal values should fit inside both IGS and ZERO-WET border variants. The analysis is based on data from seven IGS stations located in mid-latitude European region from year 2014. For the purpose of this study several days with the most active troposphere were selected for each of the station. All the PPP solutions were determined using gLAB open-source software, with the Kalman filter implemented independently by the authors of this work. The processing was performed on 1 hour slices of observation data. In addition to the analysis of the output processing files, the presented study contains detailed analysis of the tropospheric conditions for the selected data. The overall results show that for the height component the VMF1 model outperforms GPT2w and MOPS by 35-40% and ZERO-WET variant by 150%. In most of the cases all solutions converge to the same values during first

Applying Kalman filtering to investigate tropospheric effects in VLBI

Science.gov (United States)

Soja, Benedikt; Nilsson, Tobias; Karbon, Maria; Heinkelmann, Robert; Liu, Li; Lu, Cuixian; Andres Mora-Diaz, Julian; Raposo-Pulido, Virginia; Xu, Minghui; Schuh, Harald

2014-05-01

Very Long Baseline Interferometry (VLBI) currently provides results, e.g., estimates of the tropospheric delays, with a delay of more than two weeks. In the future, with the coming VLBI2010 Global Observing System (VGOS) and increased usage of electronic data transfer, it is planned that the time between observations and results is decreased. This may, for instance, allow the integration of VLBI-derived tropospheric delays into numerical weather prediction models. Therefore, future VLBI analysis software packages need to be able to process the observational data autonomously in near real-time. For this purpose, we have extended the Vienna VLBI Software (VieVS) by a Kalman filter module. This presentation describes the filter and discusses its application for tropospheric studies. Instead of estimating zenith wet delays as piece-wise linear functions in a least-squares adjustment, the Kalman filter allows for more sophisticated stochastic modeling. We start with a random walk process to model the time-dependent behavior of the zenith wet delays. Other possible approaches include the stochastic model described by turbulence theory, e.g. the model by Treuhaft and Lanyi (1987). Different variance-covariance matrices of the prediction error, depending on the time of the year and the geographic latitude, have been tested. In winter and closer to the poles, lower variances and covariances are appropriate. The horizontal variations in tropospheric delays have been investigated by comparing three different strategies: assumption of a horizontally stratified troposphere, using north and south gradients modeled, e.g., as Gauss-Markov processes, and applying a turbulence model assuming correlations between observations in different azimuths. By conducting Monte-Carlo simulations of current standard VLBI networks and of future VGOS networks, the different tropospheric modeling strategies are investigated. For this purpose, we use the simulator module of VieVS which takes into

A new diagnostic for tropospheric ozone production

Science.gov (United States)

Edwards, Peter M.; Evans, Mathew J.

2017-11-01

Tropospheric ozone is important for the Earth's climate and air quality. It is produced during the oxidation of organics in the presence of nitrogen oxides. Due to the range of organic species emitted and the chain-like nature of their oxidation, this chemistry is complex and understanding the role of different processes (emission, deposition, chemistry) is difficult. We demonstrate a new methodology for diagnosing ozone production based on the processing of bonds contained within emitted molecules, the fate of which is determined by the conservation of spin of the bonding electrons. Using this methodology to diagnose ozone production in the GEOS-Chem chemical transport model, we demonstrate its advantages over the standard diagnostic. We show that the number of bonds emitted, their chemistry and lifetime, and feedbacks on OH are all important in determining the ozone production within the model and its sensitivity to changes. This insight may allow future model-model comparisons to better identify the root causes of model differences.

A new diagnostic for tropospheric ozone production

Directory of Open Access Journals (Sweden)

P. M. Edwards

2017-11-01

Full Text Available Tropospheric ozone is important for the Earth's climate and air quality. It is produced during the oxidation of organics in the presence of nitrogen oxides. Due to the range of organic species emitted and the chain-like nature of their oxidation, this chemistry is complex and understanding the role of different processes (emission, deposition, chemistry is difficult. We demonstrate a new methodology for diagnosing ozone production based on the processing of bonds contained within emitted molecules, the fate of which is determined by the conservation of spin of the bonding electrons. Using this methodology to diagnose ozone production in the GEOS-Chem chemical transport model, we demonstrate its advantages over the standard diagnostic. We show that the number of bonds emitted, their chemistry and lifetime, and feedbacks on OH are all important in determining the ozone production within the model and its sensitivity to changes. This insight may allow future model–model comparisons to better identify the root causes of model differences.

Retrieval of tropospheric carbon monoxide for the MOPITT experiment

Science.gov (United States)

Pan, Liwen; Gille, John C.; Edwards, David P.; Bailey, Paul L.; Rodgers, Clive D.

1998-12-01

A retrieval method for deriving the tropospheric carbon monoxide (CO) profile and column amount under clear sky conditions has been developed for the Measurements of Pollution In The Troposphere (MOPITT) instrument, scheduled for launch in 1998 onboard the EOS-AM1 satellite. This paper presents a description of the method along with analyses of retrieval information content. These analyses characterize the forward measurement sensitivity, the contribution of a priori information, and the retrieval vertical resolution. Ensembles of tropospheric CO profiles were compiled both from aircraft in situ measurements and from chemical model results and were used in retrieval experiments to characterize the method and to study the sensitivity to different parameters. Linear error analyses were carried out in parallel with the ensemble experiments. Results of these experiments and analyses indicate that MOPITT CO column measurements will have better than 10% precision, and CO profile measurement will have approximately three pieces of independent information that will resolve 3-5 tropospheric layers to approximately 10% precision. These analyses are important for understanding MOPITT data, both for application of data in tropospheric chemistry studies and for comparison with in situ measurements.

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.

MLS/Aura Near-Real-Time L2 Nitrous Oxide (N2O) Mixing Ratio V003

Data.gov (United States)

National Aeronautics and Space Administration — ML2N2O_NRT is the EOS Aura Microwave Limb Sounder (MLS) Near-Real-Time (NRT) product for nitrous oxide (N2O). This product contains daily N2O profiles taken from the...

Carbon monoxide and methane in the North American Arctic and Subarctic troposphere - July-August 1988

Science.gov (United States)

Harriss, Robert C.; Sachse, Glen W.; Hill, Gerald F.; Wade, Larry; Bartlett, Karen B.; Collins, James E.; Steele, L. P.; Novelli, Paul C.

1992-01-01

Enhanced concentrations of CH4 in the unpolluted atmospheric mixed layer over both Arctic and subarctic tundra landscapes are documented here using data from the NASA Arctic Boundary Layer Expedition (ABLE 3A). The CH4 concentration gradients were determined mainly by interactions of biogenic emission from wet tundra and turbulent mixing proceses. The gradient were most frequently associated with intrusion of upper tropospheric or stratospheric air into the midtroposphere, emissions from forest and tundra fires, and long-range transport of enhanced concentration of these gases from unidentified sources. Summertime haze layers exhibited midtropospheric enhancements of CH4 similar to those measured in winter Arctic events. The observations confirm the importance of Arctic and Subarctic wetland environments as a regional source of global atmospheric CH4.

Tropospheric ozone annual variation and possible troposphere-stratosphere coupling in the Arctic and Antarctic as derived from ozone soundings at Resolute and Amundsen-Scott stations

Energy Technology Data Exchange (ETDEWEB)

Gruzdev, A.N.; Sitnov, S.A. (Russian Academy of Sciences, Moscow (Russian Federation). Inst. of Atmospheric Physics)

1993-01-01

The tropospheric ozone annual variation in the northern and southern polar regions is analyzed from ozone sounding data obtained at Resolute during a 15-year period and Amundsen-Scott during a 7-year period. The phase of ozone annual variation above Resolute changes (increases) gradually from the stratosphere across the tropopause to the middle troposphere. Unlike this, the phase of the Antarctic ozone annual harmonic has a discontinuity in the layer of the changing tropopause level, so that the annual harmonic in the upper troposphere, lower stratosphere is 4-to-5 months out of phase (earlier) to that above and beneath. Above both the Arctic and Antarctic stations, the ozone mixing ratio and its vertical gradient evolve in a similar manner in the wide layer from the lower stratosphere to the middle troposphere. This likely points out that ozone in this layer is controlled from above. An indication of the stratospheric-tropospheric ozone exchange above Resolute is noted from mid-winter to spring. The analysis of columnar tropospheric ozone changes gives a lower estimate of the cross-tropopause ozone flux up to 5x10[sup 10] mol cm[sup -2] s[sup -1]. Above the South Pole, the cross-tropopause ozone flux is not usually large. There is also some evidence that early in the spring, when the stratospheric ozone 'hole' is developed, the stratospheric-tropospheric exchange conducts the influence of the 'hole' into the upper troposphere, where the integrated ozone destruction is estimated to be 8x10[sup 10] mol cm[sup -2] s[sup -1]. Correlation analysis gives no ozone-tropopause correlation in the Antarctic in winter, while in other seasons as well as during all seasons in the Arctic, there are negative correlation peaks just above the tropopause. (19 refs., 6 figs.).

Multi-decadal satellite measurements of passive and eruptive volcanic SO2 emissions

Science.gov (United States)

Carn, Simon; Yang, Kai; Krotkov, Nickolay; Prata, Fred; Telling, Jennifer

2015-04-01

Periodic injections of sulfur gas species (SO2, H2S) into the stratosphere by volcanic eruptions are among the most important, and yet unpredictable, drivers of natural climate variability. However, passive (lower tropospheric) volcanic degassing is the major component of total volcanic emissions to the atmosphere on a time-averaged basis, but is poorly constrained, impacting estimates of global emissions of other volcanic gases (e.g., CO2). Stratospheric volcanic emissions are very well quantified by satellite remote sensing techniques, and we report ongoing efforts to catalog all significant volcanic SO2 emissions into the stratosphere and troposphere since 1978 using measurements from the ultraviolet (UV) Total Ozone Mapping Spectrometer (TOMS; 1978-2005), Ozone Monitoring Instrument (OMI; 2004 - present) and Ozone Mapping and Profiler Suite (OMPS; 2012 - present) instruments, supplemented by infrared (IR) data from HIRS, MODIS and AIRS. The database, intended for use as a volcanic forcing dataset in climate models, currently includes over 600 eruptions releasing a total of ~100 Tg SO2, with a mean eruption discharge of ~0.2 Tg SO2. Sensitivity to SO2 emissions from smaller eruptions greatly increased following the launch of OMI in 2004, but uncertainties remain on the volcanic flux of other sulfur species other than SO2 (H2S, OCS) due to difficulty of measurement. Although the post-Pinatubo 1991 era is often classified as volcanically quiescent, many smaller eruptions (Volcanic Explosivity Index [VEI] 3-4) since 2000 have injected significant amounts of SO2 into the upper troposphere - lower stratosphere (UTLS), peaking in 2008-2011. We also show how even smaller (VEI 2) tropical eruptions can impact the UTLS and sustain above-background stratospheric aerosol optical depth, thus playing a role in climate forcing on short timescales. To better quantify tropospheric volcanic degassing, we use ~10 years of operational SO2 measurements by OMI to identify the

Uplifting of carbon monoxide from biomass burning and anthropogenic sources to the free troposphere in East Asia

Science.gov (United States)

Ding, Ke; Liu, Jane; Ding, Aijun; Liu, Qiang; Zhao, Tianliang; Shi, Jiancheng; Han, Yong; Wang, Hengmao; Jiang, Fei

2016-04-01

East Asia has experienced rapid development with increasing carbon monoxide (CO) emission in the past decades. Therefore, uplifting CO from the boundary layer to the free troposphere in East Asia can have great implications on regional air quality around the world. It can also influence global climate due to the longer lifetime of CO at higher altitudes. In this study, three cases of high CO episodes in the East China Sea and the Sea of Japan from 2003 to 2005 are examined with spaceborne Measurements of Pollution in the Troposphere (MOPITT) data, in combination with aircraft measurements from the Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC) program. Through analyses of the simulations from a chemical transport model GEOS-Chem and a trajectory dispersion model FLEXPART, we found different CO signatures in the elevated CO and distinct transport pathways and mechanisms for these cases.

The Potential of Tropospheric Gradients for Regional Precipitation Prediction

Science.gov (United States)

Boisits, Janina; Möller, Gregor; Wittmann, Christoph; Weber, Robert

2017-04-01

Changes of temperature and humidity in the neutral atmosphere cause variations in tropospheric path delays and tropospheric gradients. By estimating zenith wet delays (ZWD) and gradients using a GNSS reference station network the obtained time series provide information about spatial and temporal variations of water vapour in the atmosphere. Thus, GNSS-based tropospheric parameters can contribute to the forecast of regional precipitation events. In a recently finalized master thesis at TU Wien the potential of tropospheric gradients for weather prediction was investigated. Therefore, ZWD and gradient time series at selected GNSS reference stations were compared to precipitation data over a period of six months (April to September 2014). The selected GNSS stations form two test areas within Austria. All required meteorological data was provided by the Central Institution for Meteorology and Geodynamics (ZAMG). Two characteristics in ZWD and gradient time series can be anticipated in case of an approaching weather front. First, an induced asymmetry in tropospheric delays results in both, an increased magnitude of the gradient and in gradients pointing towards the weather front. Second, an increase in ZWD reflects the increased water vapour concentration right before a precipitation event. To investigate these characteristics exemplary test events were processed. On the one hand, the sequence of the anticipated increase in ZWD at each GNSS station obtained by cross correlation of the time series indicates the direction of the approaching weather front. On the other hand, the corresponding peak in gradient time series allows the deduction of the direction of movement as well. To verify the results precipitation data from ZAMG was used. It can be deduced, that tropospheric gradients show high potential for predicting precipitation events. While ZWD time series rather indicate the orientation of the air mass boundary, gradients rather indicate the direction of movement

Global CO emission estimates inferred from assimilation of MOPITT and IASI CO data, together with observations of O3, NO2, HNO3, and HCHO.

Science.gov (United States)

Zhang, X.; Jones, D. B. A.; Keller, M.; Jiang, Z.; Bourassa, A. E.; Degenstein, D. A.; Clerbaux, C.; Pierre-Francois, C.

2017-12-01

Atmospheric carbon monoxide (CO) emissions estimated from inverse modeling analyses exhibit large uncertainties, due, in part, to discrepancies in the tropospheric chemistry in atmospheric models. We attempt to reduce the uncertainties in CO emission estimates by constraining the modeled abundance of ozone (O3), nitrogen dioxide (NO2), nitric acid (HNO3), and formaldehyde (HCHO), which are constituents that play a key role in tropospheric chemistry. Using the GEOS-Chem four-dimensional variational (4D-Var) data assimilation system, we estimate CO emissions by assimilating observations of CO from the Measurement of Pollution In the Troposphere (MOPITT) and the Infrared Atmospheric Sounding Interferometer (IASI), together with observations of O3 from the Optical Spectrograph and InfraRed Imager System (OSIRIS) and IASI, NO2 and HCHO from the Ozone Monitoring Instrument (OMI), and HNO3 from the Microwave Limb Sounder (MLS). Our experiments evaluate the inferred CO emission estimates from major anthropogenic, biomass burning and biogenic sources. Moreover, we also infer surface emissions of nitrogen oxides (NOx = NO + NO2) and isoprene. Our results reveal that this multiple species chemical data assimilation produces a chemical consistent state that effectively adjusts the CO-O3-OH coupling in the model. The O3-induced changes in OH are particularly large in the tropics. Overall, our analysis results in a better constrained tropospheric chemical state.

Nitrogen oxides in the troposphere – What have we learned from satellite measurements?

Directory of Open Access Journals (Sweden)

Richter A.

2009-02-01

Full Text Available Nitrogen oxides are key species in the troposphere where they are linked to ozone formation and acid rain. The sources of nitrogen oxides are anthropogenic to large extend, mainly through combustion of fossil fuels. Satellite observations of NO2 provide global measurements of nitrogen oxides since summer 1995, and these data have been applied for many studies on the emission sources and strengths, the chemistry and the transport of NOx. In this paper, an overview will be given on satellite measurements of NO2 , some examples of typical applications and an outlook on future prospects.

Anthropogenic influence on the distribution of tropospheric sulphate aerosol

Energy Technology Data Exchange (ETDEWEB)

Langner, J; Rodhe, H; Crutzen, P J; Zimmermann, P [Swedish Meteorological and Hydrological Institute, Norrkoeping (Sweden)

1992-10-22

Human activities have increased global emissions of sulphur gases by about a factor of three during the past century, leading to increased sulphate aerosol concentrations, mainly in the Northern Hemisphere. Sulphate aerosols can affect the climate directly, by increasing the backscattering of solar radiation in cloud-free air, and indirectly, by providing additional cloud condensation nuclei. Here a global transport-chemistry model is used to estimate the changes in the distribution of tropospheric sulphate aerosol and deposition of non-seasalt sulphur that have occurred since pre-industrial times. The increase in sulphate aerosol concentration is small over the Southern Hemisphere oceans, but reaches a factor of 100 over northern Europe in winter. Calculations indicate, however, that at most 6% of the anthropogenic sulphur emissions is available for the formation of new aerosol particles. This is because about one-half of the sulphur dioxide is deposited on the Earth's surface, and most of the remainder is oxidized in cloud droplets so that the sulphate becomes associated with pre-existing particles. Even so, the rate of formation of new sulphate particles may have doubled since pre-industrial times. 18 refs., 3 figs.

Auditory aura in nocturnal frontal lobe epilepsy: a red flag to suspect an extra-frontal epileptogenic zone.

Science.gov (United States)

Ferri, Lorenzo; Bisulli, Francesca; Nobili, Lino; Tassi, Laura; Licchetta, Laura; Mostacci, Barbara; Stipa, Carlotta; Mainieri, Greta; Bernabè, Giorgia; Provini, Federica; Tinuper, Paolo

2014-11-01

To describe the anatomo-electro-clinical findings of patients with nocturnal hypermotor seizures (NHS) preceded by auditory symptoms, to evaluate the localizing value of auditory aura. Our database of 165 patients with nocturnal frontal lobe epilepsy (NFLE) diagnosis confirmed by videopolysomnography (VPSG) was reviewed, selecting those who reported an auditory aura as the initial ictal symptom in at least two NHS during their lifetime. Eleven patients were selected (seven males, four females). According to the anatomo-electro-clinical data, three groups were identified. Group 1 [defined epileptogenic zone (EZ)]: three subjects were studied with stereo-EEG. The EZ lay in the left superior temporal gyrus in two cases, whereas in the third case seizures arose from a dysplastic lesion located in the left temporal lobe. One of these three patients underwent left Heschl's gyrus resection, and is currently seizure-free. Group 2 (presumed EZ): three cases in which a presumed EZ was identified; in the left temporal lobe in two cases and in the left temporal lobe extending to the insula in one subject. Group 3 (uncertain EZ): five cases had anatomo-electro-clinical correlations discordant. This work suggests that auditory aura may be a helpful anamnestic feature suggesting an extra-frontal seizure origin. This finding could guide secondary investigations to improve diagnostic definition and selection of candidates for surgical treatment. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

Evaluating Lightning-generated NOx (LNOx) Parameterization based on Cloud Top Height at Resolutions with Partially-resolved Convection for Upper Tropospheric Chemistry Studies

Science.gov (United States)

Wong, J.; Barth, M. C.; Noone, D. C.

2012-12-01

Lightning-generated nitrogen oxides (LNOx) is an important precursor to tropospheric ozone production. With a meteorological time-scale variability similar to that of the ozone chemical lifetime, it can nonlinearly perturb tropospheric ozone concentration. Coupled with upper-air circulation patterns, LNOx can accumulate in significant amount in the upper troposphere with other precursors, thus enhancing ozone production (see attached figure). While LNOx emission has been included and tuned extensively in global climate models, its inclusions in regional chemistry models are seldom tested. Here we present a study that evaluates the frequently used Price and Rind parameterization based on cloud-top height at resolutions that partially resolve deep convection using the Weather Research and Forecasting model with Chemistry (WRF-Chem) over the contiguous United States. With minor modifications, the parameterization is shown to generate integrated flash counts close to those observed. However, the modeled frequency distribution of cloud-to-ground flashes do not represent well for storms with high flash rates, bringing into question the applicability of the intra-cloud/ground partitioning (IC:CG) formulation of Price and Rind in some studies. Resolution dependency also requires attention when sub-grid cloud-tops are used instead of the originally intended grid-averaged cloud-top. LNOx passive tracers being gathered by monsoonal upper tropospheric anticyclone.

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 �

Intact blood-brain barrier during spontaneous attacks of migraine without aura

DEFF Research Database (Denmark)

Amin, F M; Hougaard, A; Cramer, S P

2017-01-01

BACKGROUND AND PURPOSE: The integrity of the blood-brain barrier (BBB) has been questioned in migraine, but BBB permeability has never been investigated during spontaneous migraine attacks. In the present study, BBB permeability during spontaneous attacks of migraine without aura was investigated......, brain stem, posterior pons and whole brain. The paired samples t test was used to compare Ki (permeability) values between the attack and headache-free days. RESULTS: Nineteen patients completed the study. Median time from onset of migraine attack to scan was 6.5 h (range 4.0-15.5 h). No change...

Promoting Dark Sky Protection in Chile: the Gabriel Mistral IDA Dark Sky Sanctuary and Other AURA Initiatives

Science.gov (United States)

Smith, R. Chris; Smith, Malcolm; Pompea, Stephen; Sanhueza, Pedro; AURA-Chile EPO Team

2018-01-01

For over 20 years, AURA has been leading efforts promoting the protection of dark skies in northern Chile. Efforts began in the early 1990s at AURA's Cerro Tololo Inter-American Observatory (CTIO), working in collaboration with other international observatories in Chile including Las Campanas Observatory (LCO) and the European Southern Observatory (ESO). CTIO also partnered with local communities, for example supporting Vicuña's effort to establish the first municipal observatory in Chile. Today we have developed a multifaceted effort of dark sky protection, including proactive government relations at national and local levels, a strong educational and public outreach program, and a program of highlighting international recognition of the dark skies through the IDA Dark Sky Places program. Work on international recognition has included the declaration of the Gabriel Mistral IDA Dark Sky Sanctuary, the first such IDA sanctuary in the world.

Global 3-D modeling of atmospheric ozone in the free troposphere and the stratosphere with emphasis on midlatitude regions. Final report

Energy Technology Data Exchange (ETDEWEB)

Brasseur, G.; Tie, X.; Walters, S.

1999-03-01

The authors have used several global chemical/transport models (1) to study the contribution of various physical, chemical, and dynamical processes to the budget of mid-latitude ozone in the stratosphere and troposphere; (2) to analyze the potential mechanisms which are responsible for the observed ozone perturbations at mid-latitudes of the lower stratosphere and in the upper troposphere; (3) to calculate potential changes in atmospheric ozone response to anthropogenic changes (e.g., emission of industrially manufactured CFCs, CO, and NO{sub x}) and to natural perturbations (e.g., volcanic eruptions and biomass burning); and (4) to estimate the impact of these changes on the radiative forcing to the climate system and on the level of UV-B radiation at the surface.

First detection of ammonia (NH3 in the Asian summer monsoon upper troposphere

Directory of Open Access Journals (Sweden)

M. Höpfner

2016-11-01

Full Text Available Ammonia (NH3 has been detected in the upper troposphere by the analysis of averaged MIPAS (Michelson Interferometer for Passive Atmospheric Sounding infrared limb-emission spectra. We have found enhanced amounts of NH3 within the region of the Asian summer monsoon at 12–15 km altitude. Three-monthly, 10° longitude  ×  10° latitude average profiles reaching maximum mixing ratios of around 30 pptv in this altitude range have been retrieved, with a vertical resolution of 3–8 km and estimated errors of about 5 pptv. These observations show that loss processes during transport from the boundary layer to the upper troposphere within the Asian monsoon do not deplete the air entirely of NH3. Thus, ammonia might contribute to the so-called Asian tropopause aerosol layer by the formation of ammonium aerosol particles. On a global scale, outside the monsoon area and during different seasons, we could not detect enhanced values of NH3 above the actual detection limit of about 3–5 pptv. This upper bound helps to constrain global model simulations.

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.

(abstract) Tropospheric Calibration for the Mars Observer Gravity Wave Experiment

Science.gov (United States)

Walter, Steven J.; Armstrong, John

1994-01-01

In spring 1993, microwave radiometer-based tropospheric calibration was provided for the Mars Observer gravitational wave search. The Doppler shifted X-band radio signals propagating between Earth and the Mars Observer satellite were precisely measured to determine path length variations that might signal passage of gravitational waves. Experimental sensitivity was restricted by competing sources of variability in signal transit time. Principally, fluctuations in the solar wind and ionospheric plasma density combined with fluctions in tropospheric refractivity determined the detection limit. Troposphere-induced path delay fluctions are dominated by refractive changes caused by water vapor inhomogeneities blowing through the signal path. Since passive microwave remote sensing techniques are able to determine atmospheric propagation delays, radiometer-based tropospheric calibration was provided at the Deep Space Network Uranus tracking site (DSS-15). Two microwave water vapor radiometers (WVRs), a microwave temperature profiler (MTP), and a ground based meterological station were deployed to determine line-of-sight vapor content and vertical temperature profile concurrently with Mars Observer tracking measurements. This calibration system provided the capability to correct Mars Observer Doppler data for troposphere-induced path variations. We present preliminary analysis of the Doppler and WVR data sets illustrating the utility of WVRs to calibrate Doppler data. This takes an important step toward realizing the ambitious system required to support future Ka-band Cassini satellite gravity wave tropospheric calibration system.

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

Aura OMI observations of regional SO2 and NO2 pollution changes from 2005 to 2015

Directory of Open Access Journals (Sweden)

N. A. Krotkov

2016-04-01

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 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

High-resolution inventory of NO emissions from agricultural soils over the Ile-de-France region

Energy Technology Data Exchange (ETDEWEB)

Rolland, M.-N. [INRA, AgroParisTech, UMR 1091 Environnement et Grandes Cultures, F-78850 Grignon (France); Gabrielle, B., E-mail: Benoit.Gabrielle@agroparistech.f [INRA, AgroParisTech, UMR 1091 Environnement et Grandes Cultures, F-78850 Grignon (France); Laville, P.; Cellier, P. [INRA, AgroParisTech, UMR 1091 Environnement et Grandes Cultures, F-78850 Grignon (France); Beekmann, M. [Laboratoire Inter-universitaire des Systemes Atmospheriques - CNRS, Universites Paris-Est and Paris 7, F-94 010 Creteil (France); Gilliot, J.-M.; Michelin, J.; Hadjar, D. [INRA, AgroParisTech, UMR 1091 Environnement et Grandes Cultures, F-78850 Grignon (France); Curci, G. [Dipartimento di Fisica - CETEMPS, Universita' degli Studi dell' Aquila, 67010 Coppito, L' Aquila (Italy)

2010-03-15

Arable soils are a significant source of nitric oxide (NO), a precursor of tropospheric ozone, and thereby contribute to ozone pollution. However, their actual impact on ozone formation is strongly related to their spatial and temporal emission patterns, which warrant high-resolution estimates. Here, we combined an agro-ecosystem model and geo-referenced databases to map these sources over the 12 000 km{sup 2} administrative region surrounding Paris, France, with a kilometric level resolution. The six most frequent arable crop species were simulated, with emission rates ranging from 1.4 kg N-NO ha{sup -1} yr{sup -1} to 11.1 kg N-NO ha{sup -1} yr{sup -1}. The overall emission factor for fertilizer-derived NO emissions was 1.7%, while background emissions contributed half of the total NO efflux. Emissions were strongly seasonal, being highest in spring due to fertilizer inputs. They were mostly sensitive to soil type, crops' growing season and fertilizer N rates. - The use of an agro-ecosystem model at regional scale makes it possible to map the emissions of nitric oxide from arable soils at a resolution compatible with tropospheric ozone models.

Aura y La señorita Christina: un diálogo posible

Directory of Open Access Journals (Sweden)

Mihaela Comsa

2015-01-01

Full Text Available Estudio intertextual de Aura , de Carlos Fuentes y La señorita Christina , de Mircea Eliade. Ambos textos se revelan como portadores de la capacidad de la literatura para condicionar la irrupción en nuestro mundo de otros espacios, tiempos y seres cuyas existencias no se sujetan, afortunadamente, a la prueba de la realidad fáctica, porque al ser pobladores de ‘frases imaginarias’, y por lo tanto, de ‘realidades imaginarias’, imponen su identidad autorreferencial.

Airborne measurement of peroxy radicals in the lower troposphere

Science.gov (United States)

Andrés Hernández, Maria Dolores; Horstjann, Markus; Kartal, Deniz; Krebsbach, Marc; Linke, Christian; Lichtenstern, Michael; Andrey, Javier; Burrows, John P.

2013-04-01

The importance of peroxy radicals in the tropospheric chemistry is well recognized in the scientific literature. Hydroxy- and organic peroxy radicals (HO2 and RO2, R being an organic chain) are key intermediates in the OH radical initiated oxidation of CO and SO2, of volatile organic compounds (VOC), in the ozonolysis of alkenes and photo-oxidation of carbonyl species. Peroxy radicals are responsible for the ozone production in the troposphere, the formation of peroxides and other oxidants. Although radical chemistry in the troposphere has been subject of intensive research in the past three decades, it is still very few known about the vertical distribution of peroxy radicals. Airborne observations are scarce in spite of their particular importance to improve the understanding of the tropospheric chemistry and the oxidising capacity of the atmosphere at different altitudes. In situ trace gas measurements were carried out in summer 2010 on board of the INTA (Instituto Nacional de Técnicas Aeroespaciales) C212 aircraft over Spain in the frame of the EUFAR project VERDRILLT (VERtical Distribution of Radicals In the Lower Layers of the Troposphere), and in cooperation with the DLR (Deutsches Zentrum für Luft- und Raumfahrt), the University of Wuppertal, the CEAM (Centro de Estudios Ambientales del Mediterráneo) and the UPV-EHU University in Bilbao. VERDRILLT aimed at getting a deeper understanding of the vertical distribution of peroxy radicals in the lower layers of the troposphere. Measurements were taken over urban areas and extensions of different vegetation under meteorological conditions favouring active photochemistry and convection from the ground into close atmospheric layers. Results and main findings will be presented and discussed.

Climate change projections and stratosphere-troposphere interaction

Energy Technology Data Exchange (ETDEWEB)

Scaife, Adam A.; Fereday, David R.; Butchart, Neal; Hardiman, Steven C. [Met Office Hadley Centre, Exeter (United Kingdom); Spangehl, Thomas; Cubasch, Ulrich; Langematz, Ulrike [Freie Universitaet Berlin, Berlin (Germany); Akiyoshi, Hideharu [National Institute for Environmental Studies, Tsukuba (Japan); Bekki, Slimane [LATMOS-IPSL, UVSQ, UPMC, CNRS/INSU, Paris (France); Braesicke, Peter [University of Cambridge, Cambridge (United Kingdom); Chipperfield, Martyn P. [University of Leeds, School of Earth and Environment, Leeds (United Kingdom); Gettelman, Andrew [National Center for Atmospheric Research, Boulder, CO (United States); Michou, Martine [GAME/CNRM (Meteo France, CNRS), Toulouse (France); Rozanov, Eugene [PMOD/WRC and ETHZ, Davos (Switzerland); Shepherd, Theodore G. [University of Toronto, Toronto, ON (Canada)

2012-05-15

Climate change is expected to increase winter rainfall and flooding in many extratropical regions as evaporation and precipitation rates increase, storms become more intense and storm tracks move polewards. Here, we show how changes in stratospheric circulation could play a significant role in future climate change in the extratropics through an additional shift in the tropospheric circulation. This shift in the circulation alters climate change in regional winter rainfall by an amount large enough to significantly alter regional climate change projections. The changes are consistent with changes in stratospheric winds inducing a change in the baroclinic eddy growth rate across the depth of the troposphere. A change in mean wind structure and an equatorward shift of the tropospheric storm tracks relative to models with poor stratospheric resolution allows coupling with surface climate. Using the Atlantic storm track as an example, we show how this can double the predicted increase in extreme winter rainfall over Western and Central Europe compared to other current climate projections. (orig.)

Impacts of stratospheric sulfate geoengineering on tropospheric ozone

Directory of Open Access Journals (Sweden)

L. Xia

2017-10-01

Full Text Available A range of solar radiation management (SRM techniques has been proposed to counter anthropogenic climate change. Here, we examine the potential effects of stratospheric sulfate aerosols and solar insolation reduction on tropospheric ozone and ozone at Earth's surface. Ozone is a key air pollutant, which can produce respiratory diseases and crop damage. Using a version of the Community Earth System Model from the National Center for Atmospheric Research that includes comprehensive tropospheric and stratospheric chemistry, we model both stratospheric sulfur injection and solar irradiance reduction schemes, with the aim of achieving equal levels of surface cooling relative to the Representative Concentration Pathway 6.0 scenario. This allows us to compare the impacts of sulfate aerosols and solar dimming on atmospheric ozone concentrations. Despite nearly identical global mean surface temperatures for the two SRM approaches, solar insolation reduction increases global average surface ozone concentrations, while sulfate injection decreases it. A fundamental difference between the two geoengineering schemes is the importance of heterogeneous reactions in the photochemical ozone balance with larger stratospheric sulfate abundance, resulting in increased ozone depletion in mid- and high latitudes. This reduces the net transport of stratospheric ozone into the troposphere and thus is a key driver of the overall decrease in surface ozone. At the same time, the change in stratospheric ozone alters the tropospheric photochemical environment due to enhanced ultraviolet radiation. A shared factor among both SRM scenarios is decreased chemical ozone loss due to reduced tropospheric humidity. Under insolation reduction, this is the dominant factor giving rise to the global surface ozone increase. Regionally, both surface ozone increases and decreases are found for both scenarios; that is, SRM would affect regions of the world differently in terms of air

Impacts of stratospheric sulfate geoengineering on tropospheric ozone

Science.gov (United States)

Xia, Lili; Nowack, Peer J.; Tilmes, Simone; Robock, Alan

2017-10-01

A range of solar radiation management (SRM) techniques has been proposed to counter anthropogenic climate change. Here, we examine the potential effects of stratospheric sulfate aerosols and solar insolation reduction on tropospheric ozone and ozone at Earth's surface. Ozone is a key air pollutant, which can produce respiratory diseases and crop damage. Using a version of the Community Earth System Model from the National Center for Atmospheric Research that includes comprehensive tropospheric and stratospheric chemistry, we model both stratospheric sulfur injection and solar irradiance reduction schemes, with the aim of achieving equal levels of surface cooling relative to the Representative Concentration Pathway 6.0 scenario. This allows us to compare the impacts of sulfate aerosols and solar dimming on atmospheric ozone concentrations. Despite nearly identical global mean surface temperatures for the two SRM approaches, solar insolation reduction increases global average surface ozone concentrations, while sulfate injection decreases it. A fundamental difference between the two geoengineering schemes is the importance of heterogeneous reactions in the photochemical ozone balance with larger stratospheric sulfate abundance, resulting in increased ozone depletion in mid- and high latitudes. This reduces the net transport of stratospheric ozone into the troposphere and thus is a key driver of the overall decrease in surface ozone. At the same time, the change in stratospheric ozone alters the tropospheric photochemical environment due to enhanced ultraviolet radiation. A shared factor among both SRM scenarios is decreased chemical ozone loss due to reduced tropospheric humidity. Under insolation reduction, this is the dominant factor giving rise to the global surface ozone increase. Regionally, both surface ozone increases and decreases are found for both scenarios; that is, SRM would affect regions of the world differently in terms of air pollution. In conclusion

Diurnal variation of tropospheric temperature at a tropical station

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K. Revathy

2001-08-01

Full Text Available The vertical velocity in the troposphere-lower stratosphere region measured using MST radar has been utilized to evaluate the temperature profile in the region. The diurnal variation of the tropospheric temperature on one day in August 1998 at the tropical station Gadanki (13.5° N, 79.2° E has been studied using the MST radar technique. The diurnal variation of the temperature revealed a prominent diurnal variation with the peak in the afternoon hours increasingly delayed in altitude. The tropopause temperature and altitude exhibited a clear diurnal cycle.Key words. Atmospheric composition and structure (pressure, density and temperature; troposphere - composition and chemistry; instruments and technique

Carbon monoxide and methane in the North American Arctic and Subarctic troposphere - July-August 1988

Energy Technology Data Exchange (ETDEWEB)

Harriss, R.C.; Sachse, G.W.; Hill, G.F.; Wade, L.; Bartlett, K.B.; Collins, J.E.; Steele, L.P.; Novelli, P.C. (New Hampshire Univ., Durham (United States) NASA, Langley Research Center, Hampton, VA (United States) Lockheed Engineering Sciences Co., Hampton, VA (United States) Science and Technology Corp., Hampton, VA (United States) Cooperative Inst. for Research in Environmental Sciences, Boulder, CO (United States))

1992-10-01

Enhanced concentrations of CH4 in the unpolluted atmospheric mixed layer over both Arctic and subarctic tundra landscapes are documented here using data from the NASA Arctic Boundary Layer Expedition (ABLE 3A). The CH4 concentration gradients were determined mainly by interactions of biogenic emission from wet tundra and turbulent mixing proceses. The gradient were most frequently associated with intrusion of upper tropospheric or stratospheric air into the midtroposphere, emissions from forest and tundra fires, and long-range transport of enhanced concentration of these gases from unidentified sources. Summertime haze layers exhibited midtropospheric enhancements of CH4 similar to those measured in winter Arctic events. The observations confirm the importance of Arctic and Subarctic wetland environments as a regional source of global atmospheric CH4. 33 refs.

Magnetic resonance imaging in children presenting migraine with aura: Association of hypoperfusion detected by arterial spin labelling and vasospasm on MR angiography findings.

Science.gov (United States)

Cadiot, Domitille; Longuet, Romain; Bruneau, Bertrand; Treguier, Catherine; Carsin-Vu, Aline; Corouge, Isabelle; Gomes, Constantin; Proisy, Maïa

2018-04-01

Objective A child presenting with a first attack of migraine with aura usually undergoes magnetic resonance imaging (MRI) to rule out stroke. The purpose of this study was to report vascular and brain perfusion findings in children suffering from migraine with aura on time-of-flight MR angiography (TOF-MRA) and MR perfusion imaging using arterial spin labelling (ASL). Methods We retrospectively included all children who had undergone an emergency MRI examination with ASL and TOF-MRA sequences for acute neurological deficit and were given a final diagnosis of migraine with aura. The ASL perfusion maps and TOF-MRA images were independently assessed by reviewers blinded to clinical data. A mean cerebral blood flow (CBF) value was obtained for each cerebral lobe after automatic data post-processing. Results Seventeen children were finally included. Hypoperfusion was identified in one or more cerebral lobes on ASL perfusion maps by visual assessment in 16/17 (94%) children. Vasospasm was noted within the intracranial vasculature on the TOF-MRA images in 12/17 (71%) children. All (100%) of the abnormal TOF-MRA images were associated with homolateral hypoperfusion. Mean CBF values were significantly lower ( P < 0.05) in visually hypoperfused lobes than in normally perfused lobes. Conclusion ASL and TOF-MRA are two totally non-invasive, easy-to-use MRI sequences for children in emergency settings. Hypoperfusion associated with homolateral vasospasm may suggest a diagnosis of migraine with aura.

Tropospheric ozone trend over Beijing from 2002–2010: ozonesonde measurements and modeling analysis

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Y. Wang

2012-09-01

Full Text Available Using a combination of ozonesonde data and numerical simulations of the Chemical Lagrangian Model of the Stratosphere (CLaMS, the trend of tropospheric ozone (O₃ during 2002–2010 over Beijing was investigated. Tropospheric ozone over Beijing shows a winter minimum and a broad summer maximum with a clear positive trend in the maximum summer ozone concentration over the last decade. The observed significant trend of tropospheric column ozone is mainly caused by photochemical production (3.1% yr⁻¹ for a mean level of 52 DU. This trend is close to the significant trend of partial column ozone in the lower troposphere (0–3 km resulting from the enhanced photochemical production during summer (3.0% yr⁻¹ for a mean level of 23 DU. Analysis of the CLaMS simulation shows that transport rather than chemistry drives most of the seasonality of tropospheric ozone. However, dynamical processes alone cannot explain the trend of tropospheric ozone in the observational data. Clearly enhanced ozone values and a negative vertical ozone gradient in the lower troposphere in the observational data emphasize the importance of photochemistry within the troposphere during spring and summer, and suggest that the photochemistry within the troposphere significantly contributes to the tropospheric ozone trend over Beijing during the last decade.

Isocyanic acid in a global chemistry transport model: Tropospheric distribution, budget, and identification of regions with potential health impacts

Science.gov (United States)

Young, Paul. J.; Emmons, Louisa K.; Roberts, James M.; Lamarque, Jean-FrançOis; Wiedinmyer, Christine; Veres, Patrick; Vandenboer, Trevor C.

2012-05-01

This study uses a global chemical transport model to estimate the distribution of isocyanic acid (HNCO). HNCO is toxic, and concentrations exceeding 1 ppbv have been suggested to have negative health effects. Based on fire studies, HNCO emissions were scaled to those of hydrogen cyanide (30%), resulting in yearly total emissions of 1.5 Tg for 2008, from both anthropogenic and biomass burning sources. Loss processes included heterogeneous uptake (pH dependent), dry deposition (like formic acid), and reaction with the OH radical (k = 1 × 10-15 molecule-1 cm3 s-1). Annual mean surface HNCO concentrations were highest over parts of China (maximum of 470 pptv), but episodic fire emissions gave much higher levels, exceeding 4 ppbv in tropical Africa and the Amazon, and exceeding 10 ppbv in Southeast Asia and Siberia. This suggests that large biomass burning events could result in deleterious health effects for populations in these regions. For the tropospheric budget, using the model-calculated pH the HNCO lifetime was 37 days, with the split between dry deposition and heterogeneous loss being 95%:5%. Fixing the heterogeneous loss rate at pH = 7 meant that this process dominated, accounting for ˜70% of the total loss, giving a lifetime of 6 days, and resulting in upper tropospheric concentrations that were essentially zero. However, changing the pH does not notably impact the high concentrations found in biomass burning regions. More observational data is needed to evaluate the model, as well as a better representation of the likely underestimated biofuel emissions, which could mean more populations exposed to elevated HNCO concentrations.

A Prototype of Tropospheric Delay Correction in L1-SAIF Augmentation

Science.gov (United States)

Takeichi, Noboru; Sakai, Takeyasu; Fukushima, Sounosuke; Ito, Ken

L1-SAIF signal is one of the navigation signals of Quasi-Zenith Satellite System, which provides an augmentation function for mobile users in Japan. This paper presents the detail of the tropospheric delay correction in L1-SAIF augmentation. The tropospheric delay correction information is generated at the ground station using the data collected at GEONET (GPS Earth Observation NETwork) stations. The correction message contains the information of the zenith tropospheric delay (ZTD) values at 105 Tropospheric Grid Points (TGP) in the experiment area. From this message a mobile user can acquire the ZTD value at some neighboring TGPs, and estimate the local ZTD value accurately by using a suitable ZTD model function. Only 3 L1-SAIF messages are necessary to provide all of the tropospheric correction information. Several investigations using the actual data observed at many GEONET stations overall Japan have proved that it is possible to achieve the correction accuracy of 13.2mm (rms).

Tropospheric Ozone Assessment Report: Present-day distribution and trends of tropospheric ozone relevant to climate and global atmospheric chemistry model evaluation

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A. Gaudel

2018-05-01

Full Text Available 'The Tropospheric Ozone Assessment Report' (TOAR is an activity of the International Global Atmospheric Chemistry Project. This paper is a component of the report, focusing on the present-day distribution and trends of tropospheric ozone relevant to climate and global atmospheric chemistry model evaluation. Utilizing the TOAR surface ozone database, several figures present the global distribution and trends of daytime average ozone at 2702 non-urban monitoring sites, highlighting the regions and seasons of the world with the greatest ozone levels. Similarly, ozonesonde and commercial aircraft observations reveal ozone’s distribution throughout the depth of the free troposphere. Long-term surface observations are limited in their global spatial coverage, but data from remote locations indicate that ozone in the 21st century is greater than during the 1970s and 1980s. While some remote sites and many sites in the heavily polluted regions of East Asia show ozone increases since 2000, many others show decreases and there is no clear global pattern for surface ozone changes since 2000. Two new satellite products provide detailed views of ozone in the lower troposphere across East Asia and Europe, revealing the full spatial extent of the spring and summer ozone enhancements across eastern China that cannot be assessed from limited surface observations. Sufficient data are now available (ozonesondes, satellite, aircraft across the tropics from South America eastwards to the western Pacific Ocean, to indicate a likely tropospheric column ozone increase since the 1990s. The 2014–2016 mean tropospheric ozone burden (TOB between 60°N–60°S from five satellite products is 300 Tg ± 4%. While this agreement is excellent, the products differ in their quantification of TOB trends and further work is required to reconcile the differences. Satellites can now estimate ozone’s global long-wave radiative effect, but evaluation is difficult due to limited

Stratospheric Ozone Distribution and Tropospheric General Circulation: Interconnections in the UTLS Region

Science.gov (United States)

Barodka, S.; Krasovsky, A.; Shalamyansky, A.

2014-12-01

The height of the tropopause, which divided the stratosphere and the troposphere, is a result of two rival categories of processes: the tropospheric vertical convection and the radiative heating of the stratosphere resulting from the ozone cycle. Hence, it is natural that tropospheric and stratospheric phenomena can have effect each other in manifold processes of stratosphere-troposphere interactions. In the present study we focus our attention to the "top-down" side of the interaction: the impact of stratospheric ozone distribution on the features of tropospheric circulation and the associated weather patterns and regional climate conditions. We proceed from analyzes of the observational data performed at the A.I. Voeikov Main Geophysical Observatory, which suggest a distinct correlation between stratospheric ozone distribution, synoptic formations and air-masses boundaries in the upper troposphere and the temperature field of the lower stratosphere [1]. Furthermore, we analyze local features of atmospheric general circulation and stratospheric ozone distribution from the atmospheric reanalyses and general circulation model data, focusing our attention to instantaneous positions of subtropical and polar stationary atmospheric fronts, which define regional characteristics of the general circulation cells in the troposphere and separate global tropospheric air-masses, correspond to distinct meteorological regimes in the TOC field [2, 3]. We assume that by altering the tropopause height, stratospheric ozone-related processes can have an impact on the location of the stationary atmospheric fronts, thereby exerting influence on circulation processes in troposphere and lower stratosphere. For midlatitudes, the tropopause height controls the position of the polar stationary front, which has a direct impact on the trajectory of motion of active vortices on synoptic tropospheric levels, thereby controlling weather patterns in that region and the regional climate. This

Real-Time Tropospheric Product Establishment and Accuracy Assessment in China

Science.gov (United States)

Chen, M.; Guo, J.; Wu, J.; Song, W.; Zhang, D.

2018-04-01

Tropospheric delay has always been an important issue in Global Navigation Satellite System (GNSS) processing. Empirical tropospheric delay models are difficult to simulate complex and volatile atmospheric environments, resulting in poor accuracy of the empirical model and difficulty in meeting precise positioning demand. In recent years, some scholars proposed to establish real-time tropospheric product by using real-time or near-real-time GNSS observations in a small region, and achieved some good results. This paper uses real-time observing data of 210 Chinese national GNSS reference stations to estimate the tropospheric delay, and establishes ZWD grid model in the country wide. In order to analyze the influence of tropospheric grid product on wide-area real-time PPP, this paper compares the method of taking ZWD grid product as a constraint with the model correction method. The results show that the ZWD grid product estimated based on the national reference stations can improve PPP accuracy and convergence speed. The accuracy in the north (N), east (E) and up (U) direction increase by 31.8 %,15.6 % and 38.3 %, respectively. As with the convergence speed, the accuracy of U direction experiences the most improvement.

Sulfur dioxide emissions from la soufriere volcano, st. Vincent, west indies.

Science.gov (United States)

Hoff, R M; Gallant, A J

1980-08-22

During the steady-state period of activity of La Soufriere Volcano in 1979, the mass emissions of sulfur dioxide into the troposphere amounted to a mean value of 339 +/- 126 metric tons per day. This value is similar to the sulfur dioxide emissions of other Central American volcanoes but less than those measured at Mount Etna, an exceptionally strong volcanic source of sulfur dioxide.

An upper tropospheric ‘ozone river’ from Africa to India during the 2008 Asian post-monsoon season

Directory of Open Access Journals (Sweden)

Flore Tocquer

2015-03-01

Full Text Available We have used ozone data from the Infrared Atmospheric Sounding Interferometer to follow an event of ozone-enriched air-masses in the upper troposphere from eastern Africa to northern India. The ozone transport (hereafter called ‘ozone river’ or O3R occurred during the Asian post-monsoon season in 2008 and was associated with Rossby wave propagation. The persistence of the O3R in a narrow channel was confirmed by MOZAIC airborne data over the northwestern Indian coast. The regions of origin of the O3R were identified by a transport analysis based on the Lagrangian model FLEXPART. The Lagrangian simulations combined with potential vorticity fields indicate that stratospheric intrusions are not likely to be the most important contributor to the observed O3 enhancements. A high-resolution Eulerian model, Meso-NH, with tagged tracers was used to discriminate between African biomass burning, lightnings and Indian anthropogenic pollution as potential sources of precursors for the O3R. Lightning NOx emissions, associated with convective clouds over Africa, were found to be the principal contributor to the ozone enhancement over the Indian Ocean taking advantage of a northeastward jet. This case study illustrates African lightning emissions as an important source for enhanced O3 in the upper troposphere over the Indian Ocean region during the post-monsoon season.

Urban exports to the nonurban troposphere: Results from project MISTT

International Nuclear Information System (INIS)

White, W.H.; Patterson, D.E.; Wilson, W.E. Jr.

1983-01-01

An identifiable plume of contaminated air forms downwind of metropolitan St. Louis under certain conditions. The contribution of this urban plume to tropospheric ozone and aerosol loadings is calculated from concentration and wind fields measured during Project MISTT. On all three summer days selected for study, net ozone exports reached 2-3 x 10 6 g mol/h, or about 3/2 mole per mole of emitted nitrogen, within hours of emission. Conversion of sulfur dioxide to sulfate aerosol was incomplete at the distances sampled: it is estimated that haze exports ultimately reached 500--600 km 2 /h, or 8--9 m 2 per gram of emitted sulfur. Simple extrapolation of the yields observed at St. Louis indicates that anthropogenic inputs overwhelm natural contributions to ozone and aerosols over eastern North America

Physics of the tropospheric radiopropagation

International Nuclear Information System (INIS)

Ajayi, G.O.

1989-02-01

The physics of the tropospheric radiopropagation is presented considering the atmospheric radio refractive index and taking into account the influence of precipitation and the attenuation due to the atmospheric gases. 35 refs, 20 figs, 3 tabs

Radiative forcing for changes in tropospheric O3

International Nuclear Information System (INIS)

Grossman, A.S.; Wuebbles, D.J.; Grant, K.E.

1994-06-01

We have evaluated the radiative forcing for assumed changes in tropospheric O 3 in the 500-1650 cm -1 wavenumber range. The radiative forcing calculations were performed as a function of latitude as well as for a globally and seasonally averaged model atmosphere, both in a clear sky approximation and in a model containing a representative cloud distribution. The scenarios involved radiative forcing calculations for O 3 at normal atmospheric abundance and at a tropospheric abundance depleted by 25 ppbv, at each altitude, for all northern hemisphere latitudes. Normal abundances of H 2 O, CO 2 , CH 4 , and N 2 O were included in the calculations. The IR radiative forcing was calculated using a correlated k-distribution radiative transfer model. The tropospheric radiative forcing values are compared to the IPCC formulae for ozone tropospheric forcing as well as other published values to determine the validity of the correlated k-distribution approach to the radiative forcing calculations. The results for the global average atmosphere show agreement with previous results to the order of 10 percent. We conclude that the O 3 forcing is linear in the background abundance and that the radiative forcing for ozone for the globally averaged atmosphere and the latitude averaged radiative forcing in the clear sky approximation are in agreement to within 10 percent. For the case of an atmosphere in which the tropospheric ozone has been depleted by 25 ppbv at all altitudes in the northern hemisphere, the mid latitude zone contributes ∼50 percent of the forcing, tropic zone contributes ∼37 percent of the forcing and the polar zone contributes ∼13 percent of the total forcing

Model study of the impacts of emissions, chemical and dynamical processes on the CO variability in the tropical upper troposphere and lower stratosphere

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Chunxiao Wang

2015-07-01

Full Text Available The Whole Atmosphere Community Climate Model (WACCM is used to investigate the relative importance of CO emissions, chemical and dynamical processes on temporal variations of CO in the tropical upper troposphere (UT and the lower stratosphere (LS. The semi-annual oscillation (SAO in the tropical UT and the annual oscillation (AO in the tropical LS detected in the MLS CO observations can be well captured by the model. The model simulations reveal that the CO surface emissions explain most of the SAO signals in the tropical UT, with the remainder being attributed to dynamical and chemical processes. The CO AO in the LS primarily results from combined effects of dynamical and chemical processes while the dynamical and chemical processes make opposite contributions to the CO AO signals, consistent with the previous findings. Our analysis further reveals that CO surface emissions tend to weaken the amplitude of the CO annual cycle in the tropical LS, while the annual variations in the meridional component of the Brewer–Dobson (BD circulation can amplify the annual variations of CO above 30 hPa. The model simulations also indicate that the CO annual cycle in the LS has a mixed behaviour with the annual variations of tropical upwelling reflected in CO between ~70 and ~50 hPa and a standard tape-recorder signal above 50 hPa. Moreover, the AO signals of CO exist up to 10 hPa when the chemical processes are switched off. The temporal and spatial variations of CO in the UT and near the tropopause are mainly driven by the upward transport of CO by tropical deep convection and the Asian summer monsoon circulation. In the early stage of the South Asian summer monsoon over the Bay of Bengal and the South China in the late spring and early summer, the transport of the CO surface emissions over Southeast Asia by the South Asian summer monsoon leads to an increase in the tropical CO, but the horizontal transport from the extratropics into the tropics (termed in

OMI/Aura Sulphur Dioxide (SO2) Total Column 1-orbit L2 Swath 13x24 km V003

Data.gov (United States)

National Aeronautics and Space Administration — The Ozone Monitoring Instrument (OMI) was launched aboard the EOS-Aura satellite on July 15, 2004 (1:38 pm equator crossing time, ascending mode). OMI with its 2600...

On the relationship between tropospheric conditions and widespread hot days in Iran

Science.gov (United States)

Asakereh, Hossein; Shadman, Hassan

2018-01-01

The present study investigated how the tropospheric conditions relate to the occurrence of widespread hot days (WHD) in Iran using the data of maximum daily temperature and other tropospheric variables. To better understand the tropospheric conditions during WHD, different patterns of tropospheric circulation were examined systematically. Four tropospheric types were identified based on sea level pressure (SLP). SLP, 500 hPa height, anomaly patterns, and warm advection maps were constructed for typical days of each group. The tropospheric conditions associated with hot days occurred simultaneously with a low-pressure system at sea level, a ridge at middle troposphere over Iran, and a pronounced trough over the Mediterranean Sea at 500 hPa. These conditions caused air mass from subtropical regions toward Iran. That is, northward, northeastward, and even eastward winds injected heat with warm origins toward the country. Hot days compounded by drought conditions have affected many parts of the country in different ways such as decrease in the agricultural products in numerous areas and significant discharge reduction in many rivers. The society is also very likely to face considerable challenges to cope with hot days. The findings of the study can be utilized in climate modeling and climate prediction of hot days in the country. Accordingly, water and electricity consumption can be planned with further precision and water consumption can be managed in crises.

Stratosphere-troposphere exchange in a summertime extratropical low: analysis

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J. Brioude

2006-01-01

Full Text Available Ozone and carbon monoxide measurements sampled during two commercial flights in airstreams of a summertime midlatitude cyclone are analysed with a Lagrangian-based study (backward trajectories and a Reverse Domain Filling technique to gain a comprehensive understanding of transport effects on trace gas distributions. The study demonstrates that summertime cyclones can be associated with deep stratosphere-troposphere transport. A tropopause fold is sampled twice in its life cycle, once in the lower troposphere (O3≃100 ppbv; CO≃90 ppbv in the dry airstream of the cyclone, and again in the upper troposphere (O3≃200 ppbv; CO≃90 ppbv on the northern side of the large scale potential vorticity feature associated with baroclinic development. In agreement with the maritime development of the cyclone, the chemical composition of the anticyclonic portion of the warm conveyor belt outflow (O3≃40 ppbv; CO≃85 ppbv corresponds to the lowest mixing ratios of both ozone and carbon monoxide in the upper tropospheric airborne observations. The uncertain degree of confidence of the Lagrangian-based technique applied to a 100 km segment of upper level airborne observations with high ozone (200 ppbv and relatively low CO (80 ppbv observed northwest of the cyclone prevents identification of the ozone enrichment process of air parcels embedded in the cyclonic part of the upper level outflow of the warm conveyor belt. Different hypotheses of stratosphere-troposphere exchange are discussed.

Towards positive feedbacks between vegetation and tropospheric O3

Science.gov (United States)

VanLoocke, A. D.; Bernacchi, C. J.; Ainsworth, E. A.; Betzelberger, A. M.

2011-12-01

The concentration of tropospheric ozone ([O3]) has approximately doubled since 1900 and is projected to continue increasing. The extent of this increase depends strongly on the emission of ozone precursors as well as changing temperature and humidity. The responses of vegetation to O3 may also have the potential to positively feedback on regional climate and on the cycle of O3 formation and destruction. Plant productivity is linked to feedbacks in the climate indirectly through the carbon cycle as well as directly through the partitioning of radiation into sensible and latent heat fluxes. In the troposphere, O3 reduces plant productivity, an effect that is pronounced in soybean, the 4th most important food crop in the world. The soybean-maize agro-ecosystem is the largest ecosystem in the contiguous U.S., therefore changes in productivity and water use by soybean under increasing [O3] could impact the regional climate and hydrologic cycle in Midwestern U.S. with feedback effects on tropospheric O3 production and cycling. To assess the response to increasing [O3], soybeans were grown under open-air agricultural conditions at the SoyFACE research facility. During the 2009 growing season, eight 20 m diameter plots were exposed to different [O3] ranging from 40 to 200 ppb. Measurements of leaf-level gas exchange were made on four dates throughout the growing season and non-destructive measurements of Leaf Area Index were made weekly. Canopy latent and sensible heat fluxes were measured continuously throughout the growing season (day of year 197-245) using a residual energy balance micrometeorological technique. Results show that as [O3] increased, rates of photosynthesis and stomatal conductance decreased. Productivity, (i.e. seed yield) decreased by over 60% from 40 to 200 ppb while canopy evapotranspiration decreased by 30%. Sensible heat flux increased by 30%, while the growing season average canopy temperatures increased by 1 °C and with peak increases of 2 �

OMI/Aura Cloud Pressure and Fraction (Raman Scattering) 1-Orbit L2 Swath 13x24 km V003

Data.gov (United States)

National Aeronautics and Space Administration — The reprocessed Aura OMI Version 003 Level 2 Cloud Data Product OMCLDRR is made available (in April 2012) to the public from the NASA Goddard Earth Sciences Data and...

OMI/Aura Aerosol product Multi-wavelength Algorithm Zoomed 1-Orbit L2 Swath 13x12km V003

Data.gov (United States)

National Aeronautics and Space Administration — The reprocessed OMI/Aura Level-2 Zoomed Aerosol data product OMAEROZ at 13x12 km resolution has been made available from the NASA Goddard Earth Sciences Data and...

The Impact of Upper Tropospheric Humidity from Microwave Limb Sounder on the Midlatitude Greenhouse Effect

Science.gov (United States)

Hu, Hua; Liu, W. Timothy

1998-01-01

This paper presents an analysis of upper tropospheric humidity, as measured by the Microwave Limb Sounder, and the impact of the humidity on the greenhouse effect in the midlatitudes. Enhanced upper tropospheric humidity and an enhanced greenhouse effect occur over the storm tracks in the North Pacific and North Atlantic. In these areas, strong baroclinic activity and the large number of deep convective clouds transport more water vapor to the upper troposphere, and hence increase greenhouse trapping. The greenhouse effect increases with upper tropospheric humidity in areas with a moist upper troposphere (such as areas over storm tracks), but it is not sensitive to changes in upper tropospheric humidity in regions with a dry upper troposphere, clearly demonstrating that there are different mechanisms controlling the geographical distribution of the greenhouse effect in the midlatitudes.

Impact of NO2 Profile Shape in OMI Tropospheric NO2 Retrievals

Science.gov (United States)

Lamsal, Lok; Krotkov, Nickolay A.; Pickering, K.; Schwartz, W. H.; Celarier, E. A.; Bucsela, E. J.; Gleason, J. F.; Philip, S.; Nowlan, C.; Martin, R. V.;

La imaginación enfermiza: La ciudad muerta y el gótico en Aura de Carlos Fuentes

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Miguel Ángel Náter

2004-04-01

Full Text Available Este ensayo se acerca a la novela Aura, de Carlos Fuentes, para explorar la reescritura del gótico y, sobre todo, la relación de la ciudad muerta o del pueblo abandonado, desde la perspectiva del espacio apocalíptico, entendido como la paralela desintegración de los espacios, de los cuerpos y de las mentes. El deterioro de la casa, en contraste con el adelanto tecnológico, se vincula con el cuerpo decrépito de la anciana Consuelo. La oscuridad del interior del edificio es correlato del oscurantismo y de la brujería, que producirá la alienación de Felipe Montero. Sobre la base de lo grotesco como lo expone Wolfgang Kayser, y de lo siniestro como lo propone Sigmund Freud, se pretende resaltar la importancia de Aura en la tradición novelística hispanoamericana que intenta presentar una narrativa disidente en relación con la novela del progreso y del adelanto tecnológico. En esa tendencia se incluyen, además, novelas como El lugar sin límites de José Donoso, Pedro Páramo de Juan Rulfo y Casas muertas de Miguel Otero SilvaThis essay represents an approach to the novel of Carlos Fuentes' Aura, a novel which explores the re-writing of the gothic, and above all, the relation of the dead city to the abandoned town, in the perspective of the apocalyptic space understood as the parallel disintegration of the space, of the bodies and the minds. The deterioration of the house, in contrast to the technological progress, is linked to the decrepit body of the old woman, Consuelo. The dark within the building correlates to the obscurantism and witchery that will lead to the alienation of Felipe Montero. On the basis of the grotesque as expounded by Wolfgang Kaiser, and the sinister, as propounded by Freud, the idea is to emphasize the significance of Aura in the Hispanic American tradition, which proposes a dissident narrative against the novel of progress and technological advance. This tendency also includes novels like J. Donoso' El lugar sin

Effect of hypoxia on BOLD fMRI response and total cerebral blood flow in migraine with aura patients

DEFF Research Database (Denmark)

Arngrim, Nanna; Hougaard, Anders; Schytz, Henrik W

2018-01-01

was measured in the visual cortex ROIs V1-V5. Total cerebral blood flow (CBF) was calculated by measuring the blood velocity in the internal carotid arteries and the basilar artery using phase-contrast mapping (PCM) MRI. Hypoxia induced a greater decrease in BOLD response to visual stimulation in V1-V4 in MA......Experimentally induced hypoxia triggers migraine and aura attacks in patients suffering from migraine with aura (MA). We investigated the blood oxygenation level-dependent (BOLD) signal response to visual stimulation during hypoxia in MA patients and healthy volunteers. In a randomized double......-blind crossover study design, 15 MA patients were allocated to 180 min of normobaric poikilocapnic hypoxia (capillary oxygen saturation 70-75%) or sham (normoxia) on two separate days and 14 healthy volunteers were exposed to hypoxia. The BOLD functional MRI (fMRI) signal response to visual stimulation...

Fauna helmintológica peruana: Paryphostomum huaccaci sp. n. (Echinostomotidoe parásito de Cathartes aura jota Molino, 1782

Directory of Open Access Journals (Sweden)

Nicanor Ibáñez H.

2014-06-01

Full Text Available Es motivo de la presente nota, contribuir al conocimiento de un trematodo: Paryphostomum huaccaci sp. n. perteneciente o la Familia Echinostomatidae Poche, 1926 y que parásita a Cathartes aura jota Molina, 1782.

OMI/Aura Ozone (O3) Total Column 1-Orbit L2 Swath 13x24 km V003 NRT

Data.gov (United States)

National Aeronautics and Space Administration — The OMI/Aura Level-2 Total Column Ozone Data Product OMTO3 Near Real Time data is made available from the OMI SIPS NASA for the public access. The Ozone Monitoring...

Modeled Full-Flight Aircraft Emissions Impacts on Air Quality and Their Sensitivity to Grid Resolution

Science.gov (United States)

Vennam, L. P.; Vizuete, W.; Talgo, K.; Omary, M.; Binkowski, F. S.; Xing, J.; Mathur, R.; Arunachalam, S.

2018-01-01

Aviation is a unique anthropogenic source with four-dimensional varying emissions, peaking at cruise altitudes (9–12 km). Aircraft emission budgets in the upper troposphere lower stratosphere region and their potential impacts on upper troposphere and surface air quality are not well understood. Our key objective is to use chemical transport models (with prescribed meteorology) to predict aircraft emissions impacts on the troposphere and surface air quality. We quantified the importance of including full-flight intercontinental emissions and increased horizontal grid resolution. The full-flight aviation emissions in the Northern Hemisphere contributed ~1.3% (mean, min–max: 0.46, 0.3–0.5 ppbv) and 0.2% (0.013, 0.004–0.02 μg/m3) of total O3 and PM2.5 concentrations at the surface, with Europe showing slightly higher impacts (1.9% (O3 0.69, 0.5–0.85 ppbv) and 0.5% (PM2.5 0.03, 0.01–0.05 μg/m3)) than North America (NA) and East Asia. We computed seasonal aviation-attributable mass flux vertical profiles and aviation perturbations along isentropic surfaces to quantify the transport of cruise altitude emissions at the hemispheric scale. The comparison of coarse (108 × 108 km2) and fine (36 × 36 km2) grid resolutions in NA showed ~70 times and ~13 times higher aviation impacts for O3 and PM2.5 in coarser domain. These differences are mainly due to the inability of the coarse resolution simulation to capture nonlinearities in chemical processes near airport locations and other urban areas. Future global studies quantifying aircraft contributions should consider model resolution and perhaps use finer scales near major aviation source regions. PMID:29707471

Modeled Full-Flight Aircraft Emissions Impacts on Air Quality and Their Sensitivity to Grid Resolution

Science.gov (United States)

Vennam, L. P.; Vizuete, W.; Talgo, K.; Omary, M.; Binkowski, F. S.; Xing, J.; Mathur, R.; Arunachalam, S.

2017-12-01

Aviation is a unique anthropogenic source with four-dimensional varying emissions, peaking at cruise altitudes (9-12 km). Aircraft emission budgets in the upper troposphere lower stratosphere region and their potential impacts on upper troposphere and surface air quality are not well understood. Our key objective is to use chemical transport models (with prescribed meteorology) to predict aircraft emissions impacts on the troposphere and surface air quality. We quantified the importance of including full-flight intercontinental emissions and increased horizontal grid resolution. The full-flight aviation emissions in the Northern Hemisphere contributed 1.3% (mean, min-max: 0.46, 0.3-0.5 ppbv) and 0.2% (0.013, 0.004-0.02 μg/m3) of total O3 and PM2.5 concentrations at the surface, with Europe showing slightly higher impacts (1.9% (O3 0.69, 0.5-0.85 ppbv) and 0.5% (PM2.5 0.03, 0.01-0.05 μg/m3)) than North America (NA) and East Asia. We computed seasonal aviation-attributable mass flux vertical profiles and aviation perturbations along isentropic surfaces to quantify the transport of cruise altitude emissions at the hemispheric scale. The comparison of coarse (108 × 108 km2) and fine (36 × 36 km2) grid resolutions in NA showed 70 times and 13 times higher aviation impacts for O3 and PM2.5 in coarser domain. These differences are mainly due to the inability of the coarse resolution simulation to capture nonlinearities in chemical processes near airport locations and other urban areas. Future global studies quantifying aircraft contributions should consider model resolution and perhaps use finer scales near major aviation source regions.

OMI/Aura and MODIS/Aqua Merged Cloud Product 1-Orbit L2 Swath 13x24 km V003

Data.gov (United States)

National Aeronautics and Space Administration — The OMI/Aura and MODIS/Aqua Merged Cloud Product 1-Orbit L2 Swath 13x24 km (OMMYDCLD) is a Level-2 orbital product that combines cloud parameters retrieved by the...

MLS/Aura Level 2 Nitric Acid (HNO3) Mixing Ratio V003 (ML2HNO3) at GES DISC

Data.gov (United States)

National Aeronautics and Space Administration — ML2HNO3 is the EOS Aura Microwave Limb Sounder (MLS) standard product for nitric acid derived from radiances measured by the 240 GHz radiometer at and below 10 hPa,...

MLS/Aura Level 2 Nitric Acid (HNO3) Mixing Ratio V004 (ML2HNO3) at GES DISC

Data.gov (United States)

National Aeronautics and Space Administration — ML2HNO3 is the EOS Aura Microwave Limb Sounder (MLS) standard product for nitric acid derived from radiances measured by the 240 GHz radiometer at and below 10 hPa,...

Primary intracranial angiomatoid fibrous histiocytoma presenting with anaemia and migraine-like headaches and aura as early clinical features

DEFF Research Database (Denmark)

Hansen, Jakob Møller; Larsen, Vibeke Andrée; Scheie, David

2015-01-01

A 17-year-old female with migraine with aura complained of fatigue and was diagnosed with anemia. Three years later, changes in her headache pattern prompted hospital referral. Brain MRI showed a bi-lobed extra-axial intracerebral tumor encroaching both parieto-occipital regions. The resection...

Contribution of emissions to concentrations: the TAGGING 1.0 submodel based on the Modular Earth Submodel System (MESSy 2.52)

Science.gov (United States)

Grewe, Volker; Tsati, Eleni; Mertens, Mariano; Frömming, Christine; Jöckel, Patrick

2017-07-01

sectors) to, e.g., ozone, are only marginally sensitive to changes in model resolution, though the level of detail increases. A reduction in road traffic emissions by 5 % shows that road traffic global tropospheric ozone is reduced by 4 % only, because the net ozone productivity increases. This 4 % reduction in road traffic tropospheric ozone corresponds to a reduction in total tropospheric ozone by ≈ 0.3 %, which is compensated by an increase in tropospheric ozone from other sources by 0.1 %, resulting in a reduction in total tropospheric ozone of ≈ 0.2 %. This compensating effect compares well with previous findings. The computational costs of the TAGGING submodel are low with respect to computing time, but a large number of additional tracers are required. The advantage of the tagging scheme is that in one simulation and at every time step and grid point, information is available on the contribution of different emission sectors to the ozone budget, which then can be further used in upcoming studies to calculate the respective radiative forcing simultaneously.

Tropospheric ozone climatology over Beijing: analysis of aircraft data from the MOZAIC program

Directory of Open Access Journals (Sweden)

A. J. Ding

2008-01-01

Full Text Available Ozone (O₃ profiles recorded over Beijing from 1995 to 2005 by the Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC program were analyzed to provide a first climatology of tropospheric O₃ over Beijing and the North China Plains (NCPs, one of the most populated and polluted regions in China. A pooled method was adopted in the data analysis to reduce the influence of irregular sampling frequency. The tropospheric O₃ over Beijing shows a seasonal and vertical distribution typical of mid-latitude locations in the Northern Hemisphere, but has higher daytime concentrations in the lower troposphere, when compared to New York City, Tokyo, and Paris at similar latitude. The tropospheric O₃ over Beijing exhibits a common summer maximum and a winter minimum, with a broad summer maximum in the middle troposphere and a narrower early summer (June peak in the lower troposphere. Examination of meteorological and satellite data suggests that the lower tropospheric O₃ maximum in June is a result of strong photochemical production, transport of regional pollution, and possibly also more intense burnings of biomass in Central-Eastern China. Trajectory analysis indicates that in summer the regional pollution from the NCPs, maybe mixed with urban plumes from Beijing, played important roles on the high O₃ concentrations in the boundary layer, but had limited impact on the O₃ concentrations in the middle troposphere. A comparison of the data recorded before and after 2000 reveals that O₃ in the lower troposphere over Beijing had a strong positive trend (approximately 2% per year from 1995 to 2005 in contrast to a flat or a decreasing trend over Tokyo, New York City, and Paris, indicating worsening photochemical pollution in Beijing and the NCPs.

Impact of West African Monsoon convective transport and lightning NOx production upon the upper tropospheric composition: a multi-model study

Directory of Open Access Journals (Sweden)

H. Schlager

2010-06-01

Full Text Available Within the African Monsoon Multidisciplinary Analysis (AMMA, we investigate the impact of nitrogen oxides produced by lightning (LiNOx and convective transport during the West African Monsoon (WAM upon the composition of the upper troposphere (UT in the tropics. For this purpose, we have performed simulations with 4 state-of-the-art chemistry transport models involved within AMMA, namely MOCAGE, TM4, LMDz-INCA and p-TOMCAT. The model intercomparison is complemented with an evaluation of the simulations based on both spaceborne and airborne observations. The baseline simulations show important differences between the UT CO and O3 distributions simulated by each of the 4 models when compared to measurements from the MOZAIC program and fom the Aura/MLS spaceborne sensor. We show that such model discrepancies can be explained by differences in the convective transport parameterizations and, more particularly, the altitude reached by convective updrafts (ranging between ~200–125 hPa. Concerning UT O3, the models exhibit a good agreement with the main observed features. Nevertheless the majority of models simulate low O3 concentrations compared to both MOZAIC and Aura/MLS observations south of the equator, and rather high concentrations in the Northern Hemisphere. Sensitivity studies are performed to quantify the effect of deep convective transport and the influence of LiNOx production on the UT composition. These clearly indicate that the CO maxima and the elevated O3 concentrations south of the equator are due to convective uplift of air masses impacted by Southern African biomass burning, in agreement with previous studies. Moreover, during the WAM, LiNOx from Africa are responsible for the highest UT O3 enhancements (10–20 ppbv over the tropical Atlantic between 10° S–20° N. Differences between models are primarily due to the performance of the parameterizations used to simulate lightning activity which are evaluated using spaceborne

Tropospheric ozone observations - How well can we assess tropospheric ozone changes?

Science.gov (United States)

Tarasick, D. W.; Galbally, I. E.; Ancellet, G.; Leblanc, T.; Wallington, T. J.; Ziemke, J. R.; Steinbacher, M.; Stähelin, J.; Vigouroux, C.; Hannigan, J. W.; García, O. E.; Foret, G.; Zanis, P.; Liu, X.; Weatherhead, E. C.; Petropavlovskikh, I. V.; Worden, H. M.; Osman, M.; Liu, J.; Lin, M.; Cooper, O. R.; Schultz, M. G.; Granados-Muñoz, M. J.; Thompson, A. M.; Cuesta, J.; Dufour, G.; Thouret, V.; Hassler, B.; Trickl, T.

2017-12-01

Since the early 20th century, measurements of ozone in the free troposphere have evolved and changed. Data records have different uncertainties and biases, and differ with respect to coverage, information content, and representativeness. Almost all validation studies employ ECC ozonesondes. These have been compared to UV-absorption measurements in a number of intercomparison studies, and show a modest ( 1-5%) high bias in the troposphere, with an uncertainty of 5%, but no evidence of a change over time. Umkehr, lidar, FTIR, and commercial aircraft all show modest low biases relative to the ECCs, and so -- if the ECC biases are transferable -- all agree within 1σ with the modern UV standard. Relative to the UV standard, Brewer-Mast sondes show a 20% increase in sensitivity from 1970-1995, while Japanese KC sondes show an increase of 5-10%. Combined with the shift of the global ozonesonde network to ECCs, this can induce a false positive trend, in analyses based on sonde data. Passive sounding methods -- Umkehr, FTIR and satellites -- have much lower vertical resolution than active methods, and this can limit the attribution of trends. Satellite biases are larger than those of other measurement systems, ranging between -10% and +20%, and standard deviations are large: about 10-30%, versus 5-10% for sondes, aircraft, lidar and ground-based FTIR. There is currently little information on measurement drift for satellite measurements of tropospheric ozone. This is an evident area of concern if satellite retrievals are used for trend studies. The importance of ECC sondes as a transfer standard for satellite validation means that efforts to homogenize existing records, by correcting for known changes and by adopting strict standard operating procedures, should continue, and additional research effort should be put into understanding and reducing sonde uncertainties. Representativeness is also a potential source of large errors, which are difficult to quantify. The global

Migraineurs without aura show microstructural abnormalities in the cerebellum and frontal lobe.

Science.gov (United States)

Granziera, C; Romascano, D; Daducci, A; Roche, A; Vincent, M; Krueger, G; Hadjikhani, N

2013-12-01

The involvement of the cerebellum in migraine pathophysiology is not well understood. We used a biparametric approach at high-field MRI (3 T) to assess the structural integrity of the cerebellum in 15 migraineurs with aura (MWA), 23 migraineurs without aura (MWoA), and 20 healthy controls (HC). High-resolution T1 relaxation maps were acquired together with magnetization transfer images in order to probe microstructural and myelin integrity. Clusterwise analysis was performed on T1 and magnetization transfer ratio (MTR) maps of the cerebellum of MWA, MWoA, and HC using an ANOVA and a non-parametric clusterwise permutation F test, with age and gender as covariates and correction for familywise error rate. In addition, mean MTR and T1 in frontal regions known to be highly connected to the cerebellum were computed. Clusterwise comparison among groups showed a cluster of lower MTR in the right Crus I of MWoA patients vs. HC and MWA subjects (p = 0.04). Univariate and bivariate analysis on T1 and MTR contrasts showed that MWoA patients had longer T1 and lower MTR in the right and left pars orbitalis compared to MWA (p < 0.01 and 0.05, respectively), but no differences were found with HC. Lower MTR and longer T1 point at a loss of macromolecules and/or micro-edema in Crus I and pars orbitalis in MWoA patients vs. HC and vs. MWA. The pathophysiological implications of these findings are discussed in light of recent literature.

OMI/Aura Global Ground Pixel Corners 1-Orbit L2 Swath 13x24km V003 (OMPIXCOR) at GES DISC

Data.gov (United States)

National Aeronautics and Space Administration — The Version-3 Aura Ozone Monitoring Instrument (OMI) Pixel Corner Product, OMPIXCOR, is now available from the NASA Goddard Earth Sciences Data and Information...

Differences in short-term primary motor cortex synaptic potentiation as assessed by repetitive transcranial magnetic stimulation in migraine patients with and without aura.

Science.gov (United States)

Conte, Antonella; Barbanti, Piero; Frasca, Vittorio; Iacovelli, Elisa; Gabriele, Maria; Giacomelli, Elena; Aurilia, Cinzia; Pichiorri, Floriana; Gilio, Francesca; Inghilleri, Maurizio

2010-01-01

To find out more about glutamatergic and gabaergic transmission in migraine, in this study we investigated glutamate-dependent short-term synaptic potentiation and GABA-dependent inhibitory cortical interneuron excitability as assessed by 5Hz-rTMS delivered over primary motor cortex (M1) (motor evoked potential, MEP, amplitude facilitation and cortical silent period, CSP, duration lengthening) in migraine patients with (MA) and without aura (MwoA) and healthy controls. We studied 37 patients with migraine (19 MA and 18 MwoA) and 19 healthy control subjects. 5Hz-rTMS was delivered at 120% resting motor threshold to the hand motor area of the left hemisphere with the target muscle at rest and during contraction. Three of the MA patients were also tested at the end of visual aura during a spontaneous migraine attack. ANOVA showed that the MEP significantly increased in size and CSP significantly lengthened during 5Hz-rTMS in the three groups tested. The 5Hz-rTMS-induced MEP facilitation differed significantly being highest in MA patients. In the three patients tested both ictally and interictally the MEP increased during the interictal session but remained unchanged when the visual aura ended. Our study shows that the neurophysiological feature that differentiates MA patients from MwoA patients and healthy controls is an abnormal M1 susceptibility to 5Hz-rTMS both outside and during the attack suggesting that glutamate-dependent short-term M1 cortical potentiation patterns differ in migraine with and without aura. Copyright 2009 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Freight from Space: Evaluating Freight Activity and Emissions Trends from Satellite Data

Science.gov (United States)

Bickford, E.; Holloway, T.; Oberman, J.; Janssen, M.

2012-12-01

Heavy duty diesel freight trucks are the fastest growing source of highway emissions in the U.S., with domestic freight tonnage projected to double by 2050. Highway diesel vehicles currently account for 42% of on-road emissions of nitrogen oxides (NOx), 58% of on-road fine particulate (PM2.5) emissions, and 21% of on-road carbon dioxide emissions. Because most surface air quality monitors are located in densely populated areas and not rural highways, it is difficult to use ground-based observations to validate spatial trends in transportation emissions. Therefore, we have employed satellite retrievals from the OMI instrument to inform surface freight transportation inventory estimates by validating modeled tropospheric vertical column total nitrogen dioxide (NO2) against satellite observations. For this research we built a roadway-by-roadway bottom-up diesel truck emissions inventory using GIS, the U.S. Federal Highway Administration's Freight Analysis Framework (FAF) activity dataset, and the U.S. Environmental Protection Agency's MOVES emissions model. We use freight rail emissions from the Eastern Regional Technical Advisory Committee (ERTAC), inventory emissions from the Lake Michigan's Air Directors Consortium (LADCO) and the EPA's Community Multiscale Air Qualiy (CMAQ) model to simulate ground-level and tropospheric column concentrations of NO2. We also use the combination of models and satellite data to evaluate weekday-weekend patterns of NO2 concentrations and the relative contributions of highway diesel vehicles, highway gasoline vehicles, and freight rail to transportation-related pollution. This research presents the first evaluation of surface freight transport from space-based observations. We find satellite retrievals of surface pollutants provide a useful data tool for evaluating air quality models and constraining emissions sources.

Tropospheric radiative forcing of CH4

International Nuclear Information System (INIS)

Grossman, A.S.; Grant, K.E.

1994-04-01

We have evaluated the tropospheric radiative forcing of CH 4 in the 0-3000 cm -1 wavenumber range and compared this with prior published calculations. The atmospheric test cases involved perturbed methane scenarios in both a McClatchey mid latitude, summer, clear sky approximation, model atmosphere, as well as a globally and seasonally averaged model atmosphere containing a representative cloud distribution. The scenarios involved pure CH 4 radiative forcing and CH 4 plus a mixture of H 2 O, CO 2 , O 3 , and N 2 O. The IR radiative forcing was calculated using a correlated k-distribution transmission model. The major purposes of this paper are to first, use the correlated k-distribution model to calculate the tropospheric radiative forcing for CH 4 , as the only radiatively active gas, and in a mixture with H 2 O, CO 2 , O 3 , and N 2 O, for a McClatchey mid-latitude summer, clear-sky model atmosphere, and to compare the results to those obtained in the studies mentioned above. Second, we will calculate the tropospheric methane forcing in a globally and annually averaged atmosphere with and without a representative cloud distribution in order to validate the conjecture given in IPCC (1990) that the inclusion of clouds in the forcing calculations results in forcing values which are approximately 20 percent less than those obtained using clear sky approximations

Improved simulation of tropospheric ozone by a global-multi-regional two-way coupling model system

Directory of Open Access Journals (Sweden)

Y. Yan

2016-02-01

with the ground measurements from 0.53 to 0.68, and it reduces the mean model bias from 10.8 to 6.7 ppb. Regionally, the coupled system reduces the bias by 4.6 ppb over Europe, 3.9 ppb over North America and 3.1 ppb over other regions. The two-way coupling brings O3 vertical profiles much closer to the HIPPO (for remote areas and MOZAIC (for polluted regions data, reducing the tropospheric (0–9 km mean bias by 3–10 ppb at most MOZAIC sites and by 5.3 ppb for HIPPO profiles. The two-way coupled simulation also reduces the global tropospheric column ozone by 3.0 DU (9.5 %, annual mean, bringing them closer to the OMI data in all seasons. Additionally, the two-way coupled simulation also reduces the global tropospheric mean hydroxyl radical by 5 % with improved estimates of methyl chloroform and methane lifetimes. Simulation improvements are more significant in the Northern Hemisphere, and are mainly driven by improved representation of spatial inhomogeneity in chemistry/emissions. Within the nested domains, the two-way coupled simulation reduces surface ozone biases relative to typical GEOS-Chem one-way nested simulations, due to much improved LBCs. The bias reduction is 1–7 times the bias reduction from the global to the one-way nested simulation. Improving model representations of small-scale processes is important for understanding the global and regional tropospheric chemistry.

Ozone in the Tropical Troposphere

NARCIS (Netherlands)

Peters, Wouter

2002-01-01

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

Influence of isoprene chemical mechanism on modelled changes in tropospheric ozone due to climate and land use over the 21st century

Science.gov (United States)

Squire, O. J.; Archibald, A. T.; Griffiths, P. T.; Jenkin, M. E.; Smith, D.; Pyle, J. A.

2015-05-01

Isoprene is a~precursor to tropospheric ozone, a key pollutant and greenhouse gas. Anthropogenic activity over the coming century is likely to cause large changes in atmospheric CO2 levels, climate and land use, all of which will alter the global vegetation distribution leading to changes in isoprene emissions. Previous studies have used global chemistry-climate models to assess how possible changes in climate and land use could affect isoprene emissions and hence tropospheric ozone. The chemistry of isoprene oxidation, which can alter the concentration of ozone, is highly complex, therefore it must be parameterised in these models. In this work, we compare the effect of four different reduced isoprene chemical mechanisms, all currently used in Earth system models, on tropospheric ozone. Using a box model we compare ozone in these reduced schemes to that in a more explicit scheme (the Master Chemical Mechanism) over a range of NOx and isoprene emissions, through the use of O3 isopleths. We find that there is some variability, especially at high isoprene emissions, caused by differences in isoprene-derived NOx reservoir species. A global model is then used to examine how the different reduced schemes respond to potential future changes in climate, isoprene emissions, anthropogenic emissions and land use change. We find that, particularly in isoprene-rich regions, the response of the schemes varies considerably. The wide-ranging response is due to differences in the model descriptions of the peroxy radical chemistry, particularly their relative rates of reaction towards NO, leading to ozone formation, or HO2, leading to termination. Also important is the yield of isoprene nitrates and peroxyacyl nitrate precursors from isoprene oxidation. Those schemes that produce less of these NOx reservoir species, tend to produce more ozone locally and less away from the source region. We also note changes in other key oxidants such as NO3 and OH (due to the inclusion of

OMI/Aura Surface UVB Irradiance and Erythemal Dose Daily L3 Global 1.0x1.0 deg Grid V003

Data.gov (United States)

National Aeronautics and Space Administration — The Aura-OMI Daily Gridded Surface UV Irradiance Product (OMUVBd) is now available from the NASA Goddard Earth Sciences Data and Information Services Center (GES...

SCIAMACHY formaldehyde observations: constraint for isoprene emission estimates over Europe?

Directory of Open Access Journals (Sweden)

G. Dufour

2009-03-01

Full Text Available Formaldehyde (HCHO is an important intermediate compound in the degradation of volatile organic compounds (VOCs in the troposphere. Sources of HCHO are largely dominated by its secondary production from VOC oxidation, methane and isoprene being the main precursors in unpolluted areas. As a result of the moderate lifetime of HCHO, its spatial distribution is determined by reactive hydrocarbon emissions. We focus here on Europe and investigate the influence of the different emissions on HCHO tropospheric columns with the CHIMERE chemical transport model in order to interpret the comparisons between SCIAMACHY and simulated HCHO columns. Europe was never specifically studied before for these purposes using satellite observations. The bias between measurements and model is less than 20% on average. The differences are discussed according to the errors on the model and the observations and remaining discrepancies are attributed to a misrepresentation of biogenic emissions. This study requires the characterisation of: (1 the model errors and performances concerning formaldehyde. The errors on the HCHO columns, mainly related to chemistry and mixed emission types, are evaluated to 2×10¹⁵ molecule/cm² and the model performances evaluated using surface measurements are satisfactory (~13%; (2 the observation errors that define the needs in spatial and temporal averaging for meaningful comparisons. Using SCIAMACHY observations as constraint for biogenic isoprene emissions in an inverse modelling scheme reduces their uncertainties by about a factor of two in region of intense emissions. The retrieved correction factors for the isoprene emissions range from a factor of 0.15 (North Africa to a factor of 2 (Poland, the United Kingdom depending on the regions.

Thermodynamic constraint on the depth of the global tropospheric circulation.

Science.gov (United States)

Thompson, David W J; Bony, Sandrine; Li, Ying

2017-08-01

The troposphere is the region of the atmosphere characterized by low static stability, vigorous diabatic mixing, and widespread condensational heating in clouds. Previous research has argued that in the tropics, the upper bound on tropospheric mixing and clouds is constrained by the rapid decrease with height of the saturation water vapor pressure and hence radiative cooling by water vapor in clear-sky regions. Here the authors contend that the same basic physics play a key role in constraining the vertical structure of tropospheric mixing, tropopause temperature, and cloud-top temperature throughout the globe. It is argued that radiative cooling by water vapor plays an important role in governing the depth and amplitude of large-scale dynamics at extratropical latitudes.

Global model of zenith tropospheric delay proposed based on EOF analysis

Science.gov (United States)

Sun, Langlang; Chen, Peng; Wei, Erhu; Li, Qinzheng

2017-07-01

Tropospheric delay is one of the main error budgets in Global Navigation Satellite System (GNSS) measurements. Many empirical correction models have been developed to compensate this delay, and models which do not require meteorological parameters have received the most attention. This study established a global troposphere zenith total delay (ZTD) model, called Global Empirical Orthogonal Function Troposphere (GEOFT), based on the empirical orthogonal function (EOF, also known as geographically weighted PCAs) analysis method and the Global Geodetic Observing System (GGOS) Atmosphere data from 2012 to 2015. The results showed that ZTD variation could be well represented by the characteristics of the EOF base function Ek and associated coefficients Pk. Here, E1 mainly signifies the equatorial anomaly; E2 represents north-south asymmetry, and E3 and E4 reflects regional variation. Moreover, P1 mainly reflects annual and semiannual variation components; P2 and P3 mainly contains annual variation components, and P4 displays semiannual variation components. We validated the proposed GEOFT model using tropospheric delay data of GGOS ZTD grid data and the tropospheric product of the International GNSS Service (IGS) over the year 2016. The results showed that GEOFT model has high accuracy with bias and RMS of -0.3 and 3.9 cm, respectively, with respect to the GGOS ZTD data, and of -0.8 and 4.1 cm, respectively, with respect to the global IGS tropospheric product. The accuracy of GEOFT demonstrating that the use of the EOF analysis method to characterize ZTD variation is reasonable.

Mudança no padrão biológico da migrânea com aura após a utilização da tetrabenazina: relato de caso Change in the biologic pattern of the migraine with aura after the use of tetrabenazine: case report

Directory of Open Access Journals (Sweden)

ELCIO JULIATO PIOVESAN

2000-06-01

Full Text Available A participação do sistema dopaminérgico na fisiopatologia da migrânea tem sido proposta a partir de recentes conquistas genéticas. Uma possível hipereatividade dos receptores dopaminérgicos DRD2 tornou as evidências mais contundentes neste sentido. Descrevemos paciente masculino, 31 anos, portador de distonia generalizada, secundária a hipóxia perinatal. Aos 16 anos, começou a ter crises de cefaléia que preenchiam os critérios para migrânea com aura. Três anos após tratamento da distônia com tetrabenazina, observou-se nítida redução da frequência, intensidade e duração das crises. Durante dois períodos, superiores a dois meses, a interrupção do tratamento com tetrabenazina induziu piora nas crises de migrânea. Apresentamos este relato como sendo a primeira descrição na literatura mostrando efeitos benéficos da tetrabenazina, um bloqueador dos receptores dopaminérgicos, sobre o comportamento da migrânea com aura.The influence of the dopaminergic system on the pathophysiology of migraine has been suggested as a result of recent genetic discoveries. A possible hyper-reactivity of the dopaminergic receptors DRD2 reinforced the evidence regarding this. We describe a 31 years-old male patient affected by a generalized dystonia secondary to perinatal hypoxia. At age 16, the patient started having headache crises that met the criteria for migraine with aura. After three years of treatment for dystonia with tetrabenazine, a clear reduction in the frequency, intensity and duration of the crises was perceived. During two periods longer than two months, the interruption of the treatment with tetrabenazine brought about an aggravation of the migraine crises. We present this case as being the first description in the literature showing the beneficial effects of tetrabenazine, a blocker of dopaminergic receptors, on the behavior of migraine with aura.

Benchmarking CCMI models' top-of-atmosphere flux in the 9.6-µm ozone band using AURA TES Instantaneous Radiative Kernel

Science.gov (United States)

Kuai, L.; Bowman, K. W.; Worden, H. M.; Paulot, F.; Paynter, D.; Oman, L.; Strode, S. A.; Rozanov, E.; Stenke, A.; Revell, L. E.; Plummer, D. A.

2017-12-01

The estimated ozone radiative forcing (RF) from chemical-climate models range widely from +0.2 to +0.6 Wm-2. The reason has never been well understood. Since the ozone absorption in the 9.6 μm band contributes 97% of the O3 longwave RF, the variation of outgoing longwave radiation (OLR) due to ozone is dominant by this band. The observed TOA flux over 9.6 µm ozone band by Thermal Emission Spectrometer (TES) shows the global distribution has unique spatial patterns. In addition, the simulated TOA fluxes over 9.6 µm ozone band by different models have never been evaluated against observations. The bias of TOA flux from model could be primarily contributed by the bias of temperature, water vapor and ozone. Furthermore, the sensitivity of TOA flux to tropospheric ozone (instantaneous radiative kernel, IRK) may also affected by these biases (Kuai et al., 2017). The bias in TOA flux would eventually propagate into model calculations of ozone RF and cause divergence of the predictions of future climate by models. In this study, we applied the observation-based IRK product by AURA TES to attribute the CCMI model bias in TOA flux over 9.6 µm ozone band to ozone, water vapor, air temperature, and surface temperature. The comparisons of the three CCMI models (AM3, SOCOL3 and GEOCCM) to TES observations suggest that 1) all models underestimate the TOA flux at tropics and subtropics. 2) The TOA flux bias is comparable similar by AM3 and GEOSCC (-0.2 to -0.3 W/m2) however is larger for the relative young model, SOCOL3 (-0.4 to -0.6 W/m2). 3) The contributions by surface temperature are similarly moderate (-0.2 W/m2). 4) The contribution of ozone is largest by SOCOL3 (-0.3 W/m2), smallest by GEOSCCM (less than 0.1 W/m2) and moderate by AM3 (-0.2 W/m2). 5) Overall, the contributions by atmospheric temperature are all small (less than 0.1 W/m2). 6) The contribution of water vapor is negative and small by both SOCOL3 and GEOSCCM (0.1 W/m2) however large and positive by AM3 (0

Tropospheric ozone and biomass burning in intertropical Africa

International Nuclear Information System (INIS)

Cros, B.; Nganga, D.; Delmas, R.A.; Fontan, J.

1991-01-01

To obtain a better understanding of tropospheric ozone's behavior in the equatorial belt of Africa, surface ozone measurements were made in the northern Congo (forest region) and on the other side of the equator in a savanna area. The data show a seasonal cycle with maximum values during the dry season: January and February in the northern tropics and June to October in the southern ones. Satellite data are needed to explain the eventual disappearance or non-appearance of a maximum of total tropospheric ozone during the northern dry season

OMI/Aura Surface UVB Irradiance and Erythemal Dose Daily L2 Global 0.25 deg Lat/Lon Grid V003

Data.gov (United States)

National Aeronautics and Space Administration — The Version 003 of Aura-OMI Spectral Surface UVB Irradiance and Erythemal Dose Level-2G data product (Daily level-2 data binned into global 0.25 deg Lat/Lon grids)...

Estimating NOx emissions and surface concentrations at high spatial resolution using OMI

Science.gov (United States)

Goldberg, D. L.; Lamsal, L. N.; Loughner, C.; Swartz, W. H.; Saide, P. E.; Carmichael, G. R.; Henze, D. K.; Lu, Z.; Streets, D. G.

2017-12-01

In many instances, NOx emissions are not measured at the source. In these cases, remote sensing techniques are extremely useful in quantifying NOx emissions. Using an exponential modified Gaussian (EMG) fitting of oversampled Ozone Monitoring Instrument (OMI) NO2 data, we estimate NOx emissions and lifetimes in regions where these emissions are uncertain. This work also presents a new high-resolution OMI NO2 dataset derived from the NASA retrieval that can be used to estimate surface level concentrations in the eastern United States and South Korea. To better estimate vertical profile shape factors, we use high-resolution model simulations (Community Multi-scale Air Quality (CMAQ) and WRF-Chem) constrained by in situ aircraft observations to re-calculate tropospheric air mass factors and tropospheric NO2 vertical columns during summertime. The correlation between our satellite product and ground NO2 monitors in urban areas has improved dramatically: r2 = 0.60 in new product, r2 = 0.39 in operational product, signifying that this new product is a better indicator of surface concentrations than the operational product. Our work emphasizes the need to use both high-resolution and high-fidelity models in order to re-calculate vertical column data in areas with large spatial heterogeneities in NOx emissions. The methodologies developed in this work can be applied to other world regions and other satellite data sets to produce high-quality region-specific emissions estimates.

Fatores desencadeantes de crises de migrânea em pacientes com migrânea sem aura Precipitating factors of migraine attacks in patients with migraine without aura

Directory of Open Access Journals (Sweden)

Ricardo Ierusalimschy

2002-09-01

Full Text Available Com o objetivo de estudar a distribuição de fatores desencadeantes de migrânea em uma população determinada, foram avaliados, através de entrevista pessoal, 100 pacientes que preenchiam os critérios diagnósticos para migrânea sem aura propostos pela Sociedade Internacional de Cefaléia. O estresse foi o desencadeante mais citado, respondendo pelo surgimento de crises de migrânea em 76% dos pacientes. Em seguida, em ordem de frequência decrescente, foram citados: estímulos sensoriais (75%, privação do sono (49%, jejum (48%, fatores ambientais (47%, alimentos (46%, menstruação (39%, fadiga (35%, bebidas alcoólicas (28%, sono prolongado (27%, cafeína (22%, esforço físico (20%, trauma craniano (20%, viagens (4%, atividade sexual (3%, medicamentos (2%, os movimentos do pescoço (2%, tabagismo (1% e uso de travesseiro baixo (1%. Conclui-se que determinados fatores parecem desempenhar papel importante na precipitação da migrânea.To study the distribution of triggers of migraine in a selected population, 100 patients who fulfilled the diagnostic criteria for migraine without aura as proposed by the International Headache Societywere evaluated by means of a personal interview. Stress was the most cited trigger, triggering migraine in 76%. Afterwards, in descending order of frequency, were cited sensorial stimuli (75%, sleep deprivation (49%, hunger (48%, environmental factors (47%, food (46%, menses (39%, fatigue (35%, alcohol (28%, sleep excess (27%, cafeine (22%, physical exertion (20%, head trauma (20%, trips (4%, sexual activity (3%, medications (2%, neck movements (2%, smoking (1% and the use of a low pillow (1%. It is concluded that certain factors seem to play an important role in the triggering of migraine.

Concentration variations of the tropospheric carbon dioxide over the Antarctic region

Directory of Open Access Journals (Sweden)

Shohei Murayama

1997-03-01

Full Text Available Aircraft measurements of the atmospheric CO_2 concentration have been made over Syowa Station, Antarctica since 1983. The minimum concentration of the average seasonal CO_2 cycle appears in March throughout the troposphere, while the maximum concentration occurs in mid-August in the upper troposphere and in late September in the middle and lower troposphere. The peak-to-peak amplitude of the seasonal cycle decreases with height. The CO_2 concentration increases with height during most of the year; however, this height dependency is larger from summer to early winter than in the remaining seasons. The average concentration difference between the upper troposphere and the ground surface is about 0.3ppmv. From comparisons with the results of the ground-based and aircraft measurements at southern middle and high latitudes and trajectory analysis, it is hypothesized that the seasonal cycle of height-dependent atmospheric transport processes could influence the seasonal cycle and the vertical distribution of the CO_2 concentration over Syowa Station.

Tropospheric Delay from VLBI and GNSS Measurements

Science.gov (United States)

Gubanov, V. S.

2018-02-01

Using an updated version of the QUASAR software package developed at the Institute of Applied Astronomy of the Russian Academy of Sciences, we have processed the VLBI observations within the international CONT14 program (May 6-20, 2014), in which a global network of 17 stations was involved (a total of 250 000 observations). The package update concerned the optimization of data structure and the refinement of stochastic models for the random variations in wet tropospheric delay and atomic clock difference. The main goal of this paper is to compare the VLBI determinations of the tropospheric delay with its independent determinations using global navigation satellite systems (GNSS). We show that both these determinations agree well between themselves only in the case of a global analysis of the VLBI observations, where the VLBI station coordinates are also refined, along with the tropospheric delay and the clock synchronization and Earth orientation parameters. If, alternatively, the station coordinates are insufficiently accurate and are not refined from VLBI observations, then it is appropriate not to determine the tropospheric delay from these observations, but to take it from the publicly accessible independent GNSS data. However, this requires that the VLBI and GNSS techniques operate simultaneously at a common observing site. We have established the shortcomings of the universally accepted method of stabilizing the global solution associated with the absence of a criterion for choosing reference stations and radio sources. Two ways of their elimination are proposed: (i) introducing a coordinated list of weight factors for the errors in the coordinates of such stations and sources into the stabilization algorithm and (ii) adopting a coordinated list of stations and sources the refinement of whose coordinates is not required at all for a certain time.

Chemical and aerosol characterisation of the troposphere over West Africa during the monsoon period as part of AMMA

Directory of Open Access Journals (Sweden)

C. E. Reeves

2010-08-01

Full Text Available During June, July and August 2006 five aircraft took part in a campaign over West Africa to observe the aerosol content and chemical composition of the troposphere and lower stratosphere as part of the African Monsoon Multidisciplinary Analysis (AMMA project. These are the first such measurements in this region during the monsoon period. In addition to providing an overview of the tropospheric composition, this paper provides a description of the measurement strategy (flights performed, instrumental payloads, wing-tip to wing-tip comparisons and points to some of the important findings discussed in more detail in other papers in this special issue.

The ozone data exhibits an "S" shaped vertical profile which appears to result from significant losses in the lower troposphere due to rapid deposition to forested areas and photochemical destruction in the moist monsoon air, and convective uplift of ozone-poor air to the upper troposphere. This profile is disturbed, particularly in the south of the region, by the intrusions in the lower and middle troposphere of air from the southern hemisphere impacted by biomass burning. Comparisons with longer term data sets suggest the impact of these intrusions on West Africa in 2006 was greater than in other recent wet seasons. There is evidence for net photochemical production of ozone in these biomass burning plumes as well as in urban plumes, in particular that from Lagos, convective outflow in the upper troposphere and in boundary layer air affected by nitrogen oxide emissions from recently wetted soils. This latter effect, along with enhanced deposition to the forested areas, contributes to a latitudinal gradient of ozone in the lower troposphere. Biogenic volatile organic compounds are also important in defining the composition both for the boundary layer and upper tropospheric convective outflow.

Mineral dust was found to be the most abundant and ubiquitous aerosol type in the

Susceptibility to migraine with aura: an analysis of the CACNA1A gene in the population of Valle Central de Costa Rica

International Nuclear Information System (INIS)

Rodriguez Porras, Luis Roberto

2005-01-01

The aim is to assess the role of the CACNA1A gene in the pathogenesis of migraine with aura, in a population of Valle Central Costa Rica, so as to make a clinical description of patients analyzed. 174 patients (diagnosed with migraine with aura) were studied and both parents with the genetic markers D19S221, D19S1150, D19S226 located at 2.5,0 and 2.5 cM respectively of CACNA1A. The markers were amplified by PCR and examined in an automatic DNA sequencers. There was no difference between gene frequencies of patients and the control group. The results no support the hypothesis of migraine as a channelopathy analyzed gene. (author) [es

OMI/Aura Effective Cloud Pressure and Fraction (Raman Scattering) Daily L2 Global 0.25 deg Lat/Lon Grid V003

Data.gov (United States)

National Aeronautics and Space Administration — The reprocessed Version-3 Aura OMI Level-2G Cloud data product OMCLDRRG has been made available (in April 2012) to the public from the NASA Goddard Earth Sciences...

The implications of intermediate stop operations on aviation emissions and climate

NARCIS (Netherlands)

Linke, F.; Grewe, V.; Gollnick, V

2017-01-01

Among the various transport modes aviation’s impact on climate change deserves special attention. Due to typical flight altitudes in the upper troposphere and above, the effect of aircraft engine emissions like e.g. water vapour, nitrogen oxides and aerosols on

Characterizing sampling and quality screening biases in infrared and microwave limb sounding

Science.gov (United States)

Millán, Luis F.; Livesey, Nathaniel J.; Santee, Michelle L.; von Clarmann, Thomas

2018-03-01

This study investigates orbital sampling biases and evaluates the additional impact caused by data quality screening for the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) and the Aura Microwave Limb Sounder (MLS). MIPAS acts as a proxy for typical infrared limb emission sounders, while MLS acts as a proxy for microwave limb sounders. These biases were calculated for temperature and several trace gases by interpolating model fields to real sampling patterns and, additionally, screening those locations as directed by their corresponding quality criteria. Both instruments have dense uniform sampling patterns typical of limb emission sounders, producing almost identical sampling biases. However, there is a substantial difference between the number of locations discarded. MIPAS, as a mid-infrared instrument, is very sensitive to clouds, and measurements affected by them are thus rejected from the analysis. For example, in the tropics, the MIPAS yield is strongly affected by clouds, while MLS is mostly unaffected. The results show that upper-tropospheric sampling biases in zonally averaged data, for both instruments, can be up to 10 to 30 %, depending on the species, and up to 3 K for temperature. For MIPAS, the sampling reduction due to quality screening worsens the biases, leading to values as large as 30 to 100 % for the trace gases and expanding the 3 K bias region for temperature. This type of sampling bias is largely induced by the geophysical origins of the screening (e.g. clouds). Further, analysis of long-term time series reveals that these additional quality screening biases may affect the ability to accurately detect upper-tropospheric long-term changes using such data. In contrast, MLS data quality screening removes sufficiently few points that no additional bias is introduced, although its penetration is limited to the upper troposphere, while MIPAS may cover well into the mid-troposphere in cloud-free scenarios. We emphasize that the

Real-Time Tropospheric Delay Estimation using IGS Products

Science.gov (United States)

Stürze, Andrea; Liu, Sha; Söhne, Wolfgang

2014-05-01

The Federal Agency for Cartography and Geodesy (BKG) routinely provides zenith tropospheric delay (ZTD) parameter for the assimilation in numerical weather models since more than 10 years. Up to now the results flowing into the EUREF Permanent Network (EPN) or E-GVAP (EUMETNET EIG GNSS water vapour programme) analysis are based on batch processing of GPS+GLONASS observations in differential network mode. For the recently started COST Action ES1206 about "Advanced Global Navigation Satellite Systems tropospheric products for monitoring severe weather events and climate" (GNSS4SWEC), however, rapid updates in the analysis of the atmospheric state for nowcasting applications require changing the processing strategy towards real-time. In the RTCM SC104 (Radio Technical Commission for Maritime Services, Special Committee 104) a format combining the advantages of Precise Point Positioning (PPP) and Real-Time Kinematic (RTK) is under development. The so-called State Space Representation approach is defining corrections, which will be transferred in real-time to the user e.g. via NTRIP (Network Transport of RTCM via Internet Protocol). Meanwhile messages for precise orbits, satellite clocks and code biases compatible to the basic PPP mode using IGS products are defined. Consequently, the IGS Real-Time Service (RTS) was launched in 2013 in order to extend the well-known precise orbit and clock products by a real-time component. Further messages e.g. with respect to ionosphere or phase biases are foreseen. Depending on the level of refinement, so different accuracies up to the RTK level shall be reachable. In co-operation of BKG and the Technical University of Darmstadt the real-time software GEMon (GREF EUREF Monitoring) is under development. GEMon is able to process GPS and GLONASS observation and RTS product data streams in PPP mode. Furthermore, several state-of-the-art troposphere models, for example based on numerical weather prediction data, are implemented. Hence, it

Lidar Profiling In the lower Troposphere: experience from PECAN

Science.gov (United States)

Demoz, Belay B.; Delgado, Ruben; Caroll, Brian; Vermeesch, Kevin; Whiteman, David N.; Sakai, Ricardo; Tesfay, Sium; Cooper, Lorenza

2018-04-01

Results from the PECAN (Plains Elevated Convection at Night) campaign are discussed. In particular, the utility of simple backscatter lidars/ceilometers in quantifying atmospheric dynamics parameters and variables as well as evolution of the lower tropospheric dynamics are made. Cases of bore wave dynamics and the potential of these events in lofting of low level, moist, airmass and its consequence in thunderstorm initiation are made. A suite of thermodynamic profiling instruments are combined and compared to describe and visualize lower tropospheric dynamic evolution.

Climate/chemistry feedbacks and biogenic emissions.

Science.gov (United States)

Pyle, John A; Warwick, Nicola; Yang, Xin; Young, Paul J; Zeng, Guang

2007-07-15

The oxidizing capacity of the atmosphere is affected by anthropogenic emissions and is projected to change in the future. Model calculations indicate that the change in surface ozone at some locations could be large and have significant implications for human health. The calculations depend on the precise scenarios used for the anthropogenic emissions and on the details of the feedback processes included in the model. One important factor is how natural biogenic emissions will change in the future. We carry out a sensitivity calculation to address the possible increase in isoprene emissions consequent on increased surface temperature in a future climate. The changes in ozone are significant but depend crucially on the background chemical regime. In these calculations, we find that increased isoprene will increase ozone in the Northern Hemisphere but decrease ozone in the tropics. We also consider the role of bromine compounds in tropospheric chemistry and consider cases where, in a future climate, the impact of bromine could change.

Verification and Validation of Tropospheric Model/Database

National Research Council Canada - National Science Library

Junho, choi

1998-01-01

A verification and validation of tropospheric models and databases has been performed based on ray tracing algorithm, statistical analysis, test on real time system operation, and other technical evaluation process...

Summer planetary-scale oscillations: aura MLS temperature compared with ground-based radar wind

Directory of Open Access Journals (Sweden)

C. E. Meek

2009-04-01

Full Text Available The advent of satellite based sampling brings with it the opportunity to examine virtually any part of the globe. Aura MLS mesospheric temperature data are analysed in a wavelet format for easy identification of possible planetary waves (PW and aliases masquerading as PW. A calendar year, 2005, of eastward, stationary, and westward waves at a selected latitude is shown in separate panels for wave number range −3 to +3 for period range 8 h to 30 days (d. Such a wavelet analysis is made possible by Aura's continuous sampling at all latitudes 82° S–82° N. The data presentation is suitable for examination of years of data. However this paper focuses on the striking feature of a "dish-shaped" upper limit to periods near 2 d in mid-summer, with longer periods appearing towards spring and fall, a feature also commonly seen in radar winds. The most probable cause is suggested to be filtering by the summer jet at 70–80 km, the latter being available from ground based medium frequency radar (MFR. Classically, the phase velocity of a wave must be greater than that of the jet in order to propagate through it. As an attempt to directly relate satellite and ground based sampling, a PW event of period 8d and wave number 2, which appears to be the original rather than an alias, is compared with ground based radar wind data. An appendix discusses characteristics of satellite data aliases with regard to their periods and amplitudes.

NASA Global Hawk Project Update and Future Plans: A New Tool for Earth Science Research

Science.gov (United States)

Naftel, Chris

2009-01-01

Science objectives include: First demonstration of the Global Hawk unmanned aircraft system (UAS) for NASA and NOAA Earth science research and applications; Validation of instruments on-board the Aura satellite; Exploration of trace gases, aerosols, and dynamics of remote upper Troposphere/lower Stratosphere regions; Sample polar vortex fragments and atmospheric rivers; Risk reduction for future missions that will study hurricanes and atmospheric rivers.

OMI/Aura Zoom-in Ground Pixel Corners 1-Orbit L2 Swath 13x12km V003 (OMPIXCORZ) at GES DISC

Data.gov (United States)

National Aeronautics and Space Administration — The Version-3 Aura Ozone Monitoring Instrument (OMI) Pixel Corner Product in zoom-in mode, OMPIXCORZ, is now available from the NASA Goddard Earth Sciences Data and...

Derivation of Tropospheric Ozone Climatology and Trends from TOMS Data

Science.gov (United States)

Newchurch, Michael J.; McPeters, Rich; Logan, Jennifer; Kim, Jae-Hwan

2002-01-01

This research addresses the following three objectives: (1) Derive tropospheric ozone columns from the TOMS instruments by computing the difference between total-ozone columns over cloudy areas and over clear areas in the tropics; (2) Compute secular trends in Nimbus-7 derived tropospheric Ozone column amounts and associated potential trends in the decadal-scale tropical cloud climatology; (3) Explain the occurrence of anomalously high ozone retrievals over high ice clouds.

Investigating vertical distribution patterns of lower tropospheric PM2.5 using unmanned aerial vehicle measurements

Science.gov (United States)

Li, Xiao-Bing; Wang, Dong-Sheng; Lu, Qing-Chang; Peng, Zhong-Ren; Wang, Zhan-Yong

2018-01-01

-fuel combustion sources. In addition, a 48-h backward trajectory analysis of air parcels showed that the lower tropospheric aerosol particles were mainly from emissions of local sources in the YRD region in the summer and autumn. By sharp contrast, the aerosol particles of this region in the winter were mainly of long-range transport sources from the north and northwest China due to the impact of Asian winter monsoon.

OMI/Aura TOMS-Like Ozone and Radiative Cloud Fraction Daily L3 Global 0.25x0.25 deg V003

Data.gov (United States)

National Aeronautics and Space Administration — The Version-003 of Level-3 Aura/OMI daily global TOMS-Like Total Column Ozone gridded product (OMTO3e) is generated by the NASA OMI science team by picking the best...

Global Gravity Wave Variances from Aura MLS: Characteristics and Interpretation

Science.gov (United States)

2008-12-01

slight longitudinal variations, with secondary high- latitude peaks occurring over Greenland and Europe . As the QBO changes to the westerly phase, the...equatorial GW temperature variances from suborbital data (e.g., Eck- ermann et al. 1995). The extratropical wave variances are generally larger in the...emanating from tropopause altitudes, presumably radiated from tropospheric jet stream in- stabilities associated with baroclinic storm systems that

Right-to-left shunt may be prone to affect the white matter integrity of posterior circulation in migraine without aura.

Science.gov (United States)

Xie, Hui; Bian, Yitong; Jian, Zhijie; Huo, Kang; Liu, Rui; Zhu, Dan; Zhang, Lihui; Wu, Jun; Yang, Jian; Liu, Jixin; Luo, Guogang

2018-01-01

Numerous studies have indicated an association between migraine and right-to-left shunt. However, little is known about whether right-to-left shunt has an effect on the migraine brain. This observational study aims to explore the impact of right-to-left shunt on the brain of migraine without aura on microstructural level. Thirty-five patients with migraine without aura were enrolled in this study. Contrast-enhanced Transcranial Doppler was performed to evaluate the status of right-to-left shunt. Three-dimensional T1-weighted and diffusion tensor images were acquired for data analysis. We employed voxel-based morphometry and tract-based spatial statistical analyses to assess the differences of gray and white matter between migraineurs with and without right-to-left shunt, respectively. Among the 35 patients, 19 (54.3%) patients had right-to-left shunt. There were no significant differences in headache features between migraineurs with and without right-to-left shunt. There were significant increases of mean and radial diffusivity in migraineurs with right-to-left shunt compared with migraineurs without right-to-left shunt. The alterations were primarily located in the right posterior thalamic radiation, secondly in the body of corpus callosum and the right superior corona radiata. No significant differences were observed in values of fractional anisotropy and axial diffusivity. No significant between-group differences were found in gray matter volume. Right-to-left shunt may cause alterations of white matter integrity in migraine without aura, and the alterations are more likely to be located at the posterior circulation.

Lidar Profiling In the lower Troposphere: experience from PECAN

Directory of Open Access Journals (Sweden)

Demoz Belay B.

2018-01-01

Full Text Available Results from the PECAN (Plains Elevated Convection at Night campaign are discussed. In particular, the utility of simple backscatter lidars/ceilometers in quantifying atmospheric dynamics parameters and variables as well as evolution of the lower tropospheric dynamics are made. Cases of bore wave dynamics and the potential of these events in lofting of low level, moist, airmass and its consequence in thunderstorm initiation are made. A suite of thermodynamic profiling instruments are combined and compared to describe and visualize lower tropospheric dynamic evolution.

[A case of focal epilepsy manifesting multiple psychiatric auras].

Science.gov (United States)

Ezura, Michinori; Kakisaka, Yosuke; Jin, Kazutaka; Kato, Kazuhiro; Iwasaki, Masaki; Fujikawa, Mayu; Aoki, Masashi; Nakasato, Nobukazu

2015-01-01

We present a case of epilepsy with multiple types of focal seizures that were misdiagnosed as psychiatric disorders. A 20-year-old female patient presented with a variety of episodes, including loss of consciousness, deja vu, fear, delusion of possession, violent movements, and generalized convulsions. Each of these symptoms appeared in a stereotypic manner. She was initially diagnosed with a psychiatric disorder and treated with psychoactive medications, which had no effect. Long-term video electroencephalography revealed that her episodes of violent movement with impaired consciousness and secondarily generalized seizure were epileptic events originating in the right hemisphere. High-field brain magnetic resonance imaging for detecting subtle lesions revealed bilateral lesions from periventricular nodular heterotopia. Her final diagnosis was right hemispheric focal epilepsy. Carbamazepine administration was started, which successfully controlled all seizures. The present case demonstrates the pitfall of diagnosing focal epilepsy when it presents with multiple types of psychiatric aura. Epilepsy should thus be included in differential diagnoses, considering the stereotypic nature of symptoms, to avoid misdiagnosis.

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.

Synopsis of TC4 Missions and Meteorology

Science.gov (United States)

Starr, D.; Pfister, L.; Selkirk, H.; Nguyen, L.

2007-12-01

The TC4 (Tropical Composition, Clouds and Climate Coupling) Experiment conducted 26 aircraft sorties on 13 flight days from July 17 to August 8, 2007 (23 days). Quality science observations were also obtained during the transit flights to/from from San Jose, Costa Rica, where the mission was based. On 9 days, coordinated aircraft missions were flown with the NASA ER-2 and DC-8, and with the NASA WB-57 on 3 occasions (and transit flights). The ER-2 served as an A-Train simulator (MODIS, CloudSat, CALIPSO, AIRS/TES, partial AMSR-E) while the WB-57 provided in-situ measurements of upper tropospheric cloud particles, aerosols and trace gases. The DC-8 provided both in-situ and remote sensing measurements, where the latter were focused on Aura validation, and also including a down-looking scanning precipitation radar (TRMM PR simulator). This paper will provide a synopsis of the science observations that were obtained, as regards the clouds and cloud systems sampled, from a meteorological perspective. A diversity of clouds were sampled and the meteorology proved more interesting than expected, at least to this author. Upper tropospheric cirrus outflows were sampled from a number of convective cloud systems including ITCZ-type systems as well as systems close to and affected by land. The low level inflows to these systems were also sampled in some cases (DC-8) and missions were flown to sample stratocumulus clouds over the Pacific Ocean exploiting the unique instrumentation on the DC-8 to add to the knowledge of these clouds which are so important to the Earth radiation budget. Measurements were made in the tropical Tropopause Transition Layer (TTL) by the WB-57. Upper tropospheric clouds and TTL properties and processes were central TC4 objectives. Excellent data were also obtained on the fate of the Saharan Air Layer and its aerosols over the Caribbean and Central America, as well as samples of plumes from volcanoes in Ecuador and Columbia and biogenic emissions over

OMI/Aura Cloud Pressure and Fraction (O2-O2 Absorption) 1-Orbit L2 Swath 13x24km V003

Data.gov (United States)

National Aeronautics and Space Administration — The reprocessed OMI/Aura Level-2 cloud data product OMCLDO2 is now available from the NASA GoddardEarth Sciences Data and Information Services Center (GES DISC) for...

OMI/Aura Near UV Aerosol Optical Depth and Single Scattering Albedo 1-orbit L2 Swath 13x24 km V003

Data.gov (United States)

National Aeronautics and Space Administration — The OMI/Aura level-2 near UV Aerosol data product 'OMAERUV', recently re-processed using an enhanced algorithm, is now released (April 2012) to the public. The data...

The Tropospheric Products of the International VLBI Service for Geodesy and Astrometry

Science.gov (United States)

Heinkelmann, Robert; Schwatke, Christian

2010-01-01

The IVS runs two tropospheric products: The IVS tropospheric parameter rapid combination monitors the zenith wet delay (ZWD) and zenith total delay (ZTD) of the rapid turnaround sessions R1 and R4. Goal of the combination is the identification and the exclusion of outliers by comparison and the assessment of the precision of current VLBI solutions in terms of tropospheric parameters. The rapid combination is done on a weekly basis four weeks after the observation files are released on IVS Data Centers. Since tropospheric and geodetic parameters, such as vertical station components, can significantly correlate, the consistency of the ZTD can be a measure of the consistency of the corresponding TRF as well. The ZWD mainly rely on accurate atmospheric pressure data. Thus, besides estimation techniques, modeling and analyst s noise, ZWD reflects differences in the atmospheric pressure data applied to the VLBI analysis. The second product, called tropospheric parameter long-term combination, aims for an accurate determination of climatological signals, such as trends of the atmospheric water vapor observed by VLBI. Therefore, the long-term homogeneity of atmospheric pressure data plays a crucial role for this product. The paper reviews the methods applied and results achieved so far and describes the new maintenance through DGFI.

Seasonal variations and vertical features of aerosol particles in the Antarctic troposphere

Directory of Open Access Journals (Sweden)

Keiichiro Hara

2010-12-01

Full Text Available Tethered balloon-borne aerosol measurements were carried out at Syowa Station, Antarctica during the 46th Japanese Antarctic Research Expedition. CN concentration had a maximum in the summer, whereas the number concentrations of fine particles (D_p>0.3 μm and coarse particles (D_p>2.0 μm increased during the winter-spring. The range of CN concentration was 30-2200 cm^ near the surface (surface-500 m and 7-7250 cm^ in the lower free troposphere (>1500 m. During the austral summer, higher CN concentration was often observed in the lower free troposphere. Frequent appearance of higher CN concentration in the free troposphere relative to the surface measurements strongly suggests that new particle formation in the Antarctic regions occurs in the lower free troposphere. Single particle analysis indicated that most of the aerosol particles during the winter were composed of Mg-enriched sea-salt particles originated from sea-salt fractionation on the sea-ice and their modified particles by NO_3^ and SO_4^. This suggests that sea-salt fractionation on sea-ice and modification of sea-salt particles were affected greatly by aerosol hygroscopicity during the winter. Antarctic haze layer was observed not only in the boundary layer but also in the lower free troposphere.

The global warming potential of methane reassessed with combined stratosphere and troposphere chemistry

Science.gov (United States)

Holmes, C. D.; Archibald, A. T.; Eastham, S. D.; Søvde, O. A.

2017-12-01

Methane is a direct and indirect greenhouse gas. The direct greenhouse effect comes from the radiation absorbed and emitted by methane itself. The indirect greenhouse effect comes from radiatively active gases that are produced during methane oxidation: principally O3, H2O, and CO2. Methane also suppresses tropospheric OH, which indirectly affects numerous greenhouses gases and aerosols. Traditionally, the methane global warming potential (GWP) has included the indirect effects on tropospheric O3 and OH and stratospheric H2O, with these effects estimated independently from unrelated tropospheric and stratospheric chemistry models and observations. Using this approach the CH4 is about 28 over 100 yr (without carbon cycle feedbacks, IPCC, 2013). Here we present a comprehensive analysis of the CH4 GWP in several 3-D global atmospheric models capable of simulating both tropospheric and stratospheric chemistry (GEOS-Chem, Oslo CTM3, UKCA). This enables us to include, for the first time, the indirect effects of CH4 on stratospheric O3 and stratosphere-troposphere coupling. We diagnose the GWP from paired simulations with and without a 5% perturbation to tropospheric CH4 concentrations. Including stratospheric chemistry nearly doubles the O3 contribution to CH4 GWP because of O3 production in the lower stratosphere and because CH4 inhibits Cl-catalyzed O3 loss in the upper stratosphere. In addition, stratosphere-troposphere coupling strengthens the chemical feedback on its own lifetime. In the stratosphere, this feedback operates by a CH4 perturbation thickening the stratospheric O3 layer, which impedes UV-driven OH production in the troposphere and prolongs the CH4 lifetime. We also quantify the impact of CH4-derived H2O on the stratospheric HOx cycles but these effects are small. Combining all of the above, these models suggest that the 100-yr GWP of CH4 is over 33.5, a 20% increase over the latest IPCC assessment.

Relationship between changes in the upper and lower tropospheric water vapor: A revisit

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Yang, M.; Sun, D. Z.; Zhang, G. J.

2017-12-01

Upper tropospheric water vapor response to enhanced greenhouse gas forcing is as important as the lower tropospheric water vapor response in determining climate sensitivity. Early studies using older versions of climate models have suggested that the upper- and lower-troposphere water vapor changes are more strongly coupled in the climate models than in the observations. Here we reexamine this issue using a state-of-the-art climate model—the NCAR community model CAM5. Specifically, we have calculated the correlations between interannual variations of specific humidity in all levels of the troposphere with that at the surface in CAM5 and in the observations (as represented by the updated ERA-Interim and NCEP reanalysis). It is found that the previously noted biases in how strongly upper tropospheric water vapor and lower troposphere water vapor are linked still exist in CAM5—the change in the tropical averaged upper tropospheric water vapor is more strongly correlated with the change in the surface. However, this bias disappears in the averaged correlation obtained by averaging the point-by-point correlations over the tropics. The spatial pattern of the point-by-point correlations reveals that the better agreement between the model and the observations is related to the opposite model biases in different regions: the correlation is weaker in the model in the western Pacific, but stronger in the central and eastern Pacific. Further analysis of precipitation fields suggests that the weaker (stronger) coupling between tropospheric water vapor and surface moisture over western (central-eastern) Pacific in model is related to weaker (stronger) simulated convective activities in these regions. More specifically, during El Nino, the model has excessive deep convection in the central Pacific, but too littler deep convection in western Pacific. Implications of the results are discussed in the context of climate change as well as in the context of how to improve the model

OMI/Aura Multi-wavelength Aerosol Optical Depth and Single Scattering Albedo 1-orbit L2 Swath 13x24 km V003

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National Aeronautics and Space Administration — The improved Level-2 OMI Aerosol Product 'OMAERO' is now available (http://disc.gsfc.nasa.gov/Aura/OMI/omaero_v003.shtml ) from NASA GSFC Earth Sciences (GES) Data...

Global impacts of tropospheric halogens (Cl, Br, I on oxidants and composition in GEOS-Chem

Directory of Open Access Journals (Sweden)

T. Sherwen

2016-09-01

Full Text Available We present a simulation of the global present-day composition of the troposphere which includes the chemistry of halogens (Cl, Br, I. Building on previous work within the GEOS-Chem model we include emissions of inorganic iodine from the oceans, anthropogenic and biogenic sources of halogenated gases, gas phase chemistry, and a parameterised approach to heterogeneous halogen chemistry. Consistent with Schmidt et al. (2016 we do not include sea-salt debromination. Observations of halogen radicals (BrO, IO are sparse but the model has some skill in reproducing these. Modelled IO shows both high and low biases when compared to different datasets, but BrO concentrations appear to be modelled low. Comparisons to the very sparse observations dataset of reactive Cl species suggest the model represents a lower limit of the impacts of these species, likely due to underestimates in emissions and therefore burdens. Inclusion of Cl, Br, and I results in a general improvement in simulation of ozone (O3 concentrations, except in polar regions where the model now underestimates O3 concentrations. Halogen chemistry reduces the global tropospheric O3 burden by 18.6 %, with the O3 lifetime reducing from 26 to 22 days. Global mean OH concentrations of 1.28  ×  106 molecules cm−3 are 8.2 % lower than in a simulation without halogens, leading to an increase in the CH4 lifetime (10.8 % due to OH oxidation from 7.47 to 8.28 years. Oxidation of CH4 by Cl is small (∼  2 % but Cl oxidation of other VOCs (ethane, acetone, and propane can be significant (∼  15–27 %. Oxidation of VOCs by Br is smaller, representing 3.9 % of the loss of acetaldehyde and 0.9 % of the loss of formaldehyde.