Environmentally dependent dust chemistry of a super Asian dust storm in March 2010: observation and simulation

Science.gov (United States)

Wang, Qiongzhen; Dong, Xinyi; Fu, Joshua S.; Xu, Jian; Deng, Congrui; Jiang, Yilun; Fu, Qingyan; Lin, Yanfen; Huang, Kan; Zhuang, Guoshun

2018-03-01

Near-surface and vertical in situ measurements of atmospheric particles were conducted in Shanghai during 19-23 March 2010 to explore the transport and chemical evolution of dust particles in a super dust storm. An air quality model with optimized physical dust emission scheme and newly implemented dust chemistry was utilized to study the impact of dust chemistry on regional air quality. Two discontinuous dust periods were observed with one traveling over northern China (DS1) and the other passing over the coastal regions of eastern China (DS2). Stronger mixing extents between dust and anthropogenic emissions were found in DS2, reflected by the higher SO2 / PM10 and NO2 / PM10 ratios as well as typical pollution elemental species such as As, Cd, Pb, and Zn. As a result, the concentrations of SO42- and NO3- and the ratio of Ca2+ / Ca were more elevated in DS2 than in DS1 but opposite for the [NH4+] / [SO42-+NO3-] ratio, suggesting the heterogeneous reactions between calcites and acid gases were significantly promoted in DS2 due to the higher level of relative humidity and gaseous pollution precursors. Lidar observation showed a columnar effect on the vertical structure of particle optical properties in DS1 that dust dominantly accounted for ˜ 80-90 % of the total particle extinction from near the ground to ˜ 700 m. In contrast, the dust plumes in DS2 were restrained within lower altitudes while the extinction from spherical particles exhibited a maximum at a high altitude of ˜ 800 m. The model simulation reproduced relatively consistent results with observations that strong impacts of dust heterogeneous reactions on secondary aerosol formation occurred in areas where the anthropogenic emissions were intensive. Compared to the sulfate simulation, the nitrate formation on dust is suggested to be improved in the future modeling efforts.

Implementation of dust emission and chemistry into the Community Multiscale Air Quality modeling system and initial application to an Asian dust storm episode

Directory of Open Access Journals (Sweden)

K. Wang

2012-11-01

Full Text Available The US Environmental Protection Agency's (EPA Community Multiscale Air Quality (CMAQ modeling system version 4.7 is further developed to enhance its capability in simulating the photochemical cycles in the presence of dust particles. The new model treatments implemented in CMAQ v4.7 in this work include two online dust emission schemes (i.e., the Zender and Westphal schemes, nine dust-related heterogeneous reactions, an updated aerosol inorganic thermodynamic module ISORROPIA II with an explicit treatment of crustal species, and the interface between ISORROPIA II and the new dust treatments. The resulting improved CMAQ (referred to as CMAQ-Dust, offline-coupled with the Weather Research and Forecast model (WRF, is applied to the April 2001 dust storm episode over the trans-Pacific domain to examine the impact of new model treatments and understand associated uncertainties. WRF/CMAQ-Dust produces reasonable spatial distribution of dust emissions and captures the dust outbreak events, with the total dust emissions of ~111 and 223 Tg when using the Zender scheme with an erodible fraction of 0.5 and 1.0, respectively. The model system can reproduce well observed meteorological and chemical concentrations, with significant improvements for suspended particulate matter (PM, PM with aerodynamic diameter of 10 μm, and aerosol optical depth than the default CMAQ v4.7. The sensitivity studies show that the inclusion of crustal species reduces the concentration of PM with aerodynamic diameter of 2.5 μm (PM_2.5 over polluted areas. The heterogeneous chemistry occurring on dust particles acts as a sink for some species (e.g., as a lower limit estimate, reducing O₃ by up to 3.8 ppb (~9% and SO₂ by up to 0.3 ppb (~27% and as a source for some others (e.g., increasing fine-mode SO₄²⁻ by up to 1.1 μg m⁻³ (~12% and PM_2.5 by up to 1.4 μg m⁻³ (~3% over the domain. The

Origin-Dependent Variations in the Atmospheric Microbiome in Eastern Mediterranean Dust Storms

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Rudich, Y.; Gat, D.

2017-12-01

Microorganisms carried by dust storms are transported through the atmosphere and may affect human health and the functionality of microbial communities in various environments. Characterizing the dust-borne microbiome in dust storms of different origins, or that followed different trajectories, provides valuable data to improve our understanding of global health and environmental impacts. We present a comparative study on the diversity of dust- borne bacterial communities in dust storms from three distinct origins—North Africa, Syria and Saudi Arabia—and compare them with local bacterial communities sampled on clear days, all collected at a single location, in Israel. Storms from different dust origins exhibited distinct bacterial communities, with signature bacterial taxa for each source. Dust storms were characterized by a lower abundance of selected antibiotic resistance genes (ARGs) compared with ambient dust, asserting that the origin of these genes is local, possibly anthropogenic. With the progression of the storm, the storm-borne bacterial community showed increasing resemblance to ambient dust, suggesting mixing with local dust. We will also discuss how exposure to dust containing biological components affect lung epithelial cells. These results show, for the first time, that dust storms from different sources display distinct bacterial communities, suggesting possible distinct effects on the environment and public health.

Dust Storm Feature Identification and Tracking from 4D Simulation Data

Science.gov (United States)

Yu, M.; Yang, C. P.

2016-12-01

Dust storms cause significant damage to health, property and the environment worldwide every year. To help mitigate the damage, dust forecasting models simulate and predict upcoming dust events, providing valuable information to scientists, decision makers, and the public. Normally, the model simulations are conducted in four-dimensions (i.e., latitude, longitude, elevation and time) and represent three-dimensional (3D), spatial heterogeneous features of the storm and its evolution over space and time. This research investigates and proposes an automatic multi-threshold, region-growing based identification algorithm to identify critical dust storm features, and track the evolution process of dust storm events through space and time. In addition, a spatiotemporal data model is proposed, which can support the characterization and representation of dust storm events and their dynamic patterns. Quantitative and qualitative evaluations for the algorithm are conducted to test the sensitivity, and capability of identify and track dust storm events. This study has the potential to assist a better early warning system for decision-makers and the public, thus making hazard mitigation plans more effective.

[Geochemical characteristics and sources of atmospheric particulates in Shanghai during dust storm event].

Science.gov (United States)

Qian, Peng; Zheng, Xiang-min; Zhou, Li-min

2013-05-01

Atmospheric particulates were sampled from three sampling sites of Putuo, Minhang and Qingpu Districts in Shanghai between Oct. , 2009 and Oct. , 2010. In addition, particulate samples were also collected from Nantong, Zhengzhou, Xi'an, and Beijing city where dust storm dust transported along during spring. Element compositions of atmospheric particulates were determined by XRF and ICP-MS. The concentrations of major and trace elements in atmospheric particulates from Putuo, Minhang and Qingpu Districts were similar, indicating their common source. The UCC standardization distribution map showed that the major element composition of dust storm samples was similar to that of loess in northwestern China, indicating that the dust storm dust was mainly derived from Western desert and partly from local area. The REE partition patterns of dust storm dusts among different cities along dust transport route were similar to each other, as well as to those of northern loess, which indicates that the dust storm samples may have the same material source as loess, which mainly comes from crust material. However, the REE partition patterns of non-dust storm particulates were different among the studied cities, and different from those of loess, which suggests that the non-dust storm samples may be mixed with non-crust source material, which is different from dust storm dust and loess. The major element composition and REE partition pattern are effective indicators for source tracing of dust storm dust.

Spring Dust Storm Smothers Beijing

Science.gov (United States)

2002-01-01

A few days earlier than usual, a large, dense plume of dust blew southward and eastward from the desert plains of Mongolia-quite smothering to the residents of Beijing. Citizens of northeastern China call this annual event the 'shachenbao,' or 'dust cloud tempest.' However, the tempest normally occurs during the spring time. The dust storm hit Beijing on Friday night, March 15, and began coating everything with a fine, pale brown layer of grit. The region is quite dry; a problem some believe has been exacerbated by decades of deforestation. According to Chinese government estimates, roughly 1 million tons of desert dust and sand blow into Beijing each year. This true-color image was made using two adjacent swaths (click to see the full image) of data from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS), flying aboard the OrbView-2 satellite, on March 17, 2002. The massive dust storm (brownish pixels) can easily be distinguished from clouds (bright white pixels) as it blows across northern Japan and eastward toward the open Pacific Ocean. The black regions are gaps between SeaWiFS' viewing swaths and represent areas where no data were collected. Image courtesy the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

Thermal tides and Martian dust storms: Direct evidence for coupling

International Nuclear Information System (INIS)

Leovy, C.B.; Zurek, R.W.

1979-01-01

Observations of surface pressure oscillations at the Viking 1 and Viking 2 lander sites on Mars indicate that the thermally driven global atmospheric tides were closely coupled to the dust content of the Martian atmosphere, especially during northern fall and winter, when two successive global dust storms occurred. The onset of each of these global storms was marked by substantial, nearly simultaneous increases in the dust opacity and in the range of the daily surface pressure variation observed at both lander sites. Although both the diurnal and semidiurnal tidal surface pressure components were amplified at Lander 1 during the onset of a global dust storm, the semidiurnal component was greatly enhanced in relation to the diurnal tide. Semidiurnal wind components were prominent at both lander sites during the height of the global dust storm. We have attempted to interpret these observations using simplified dynamical models. In particular, the semidiurnal wind component can be successfully related to the observed surface pressure variation using a simplified model of a semidiurnally forced Ekman boundary layer. On the other hand, a classical atmospheric tidal model shows that the preferential enhancement of the semidiurnal surface pressure oscillation at Lander 1 can be produced by a tidal heating distribution which places most of the heating (per unit mass) above 10-km altitude. Furthermore, when a dust storm expands to global scale, it does so rather quickly, and the total atmospheric heating at the peak of the dust storm can represent more than 50% of the available insolation. The Viking observations suggest that a number of mechanisms are important for the generation and decay of these episodic Martian global dust storms

Meteorological aspects associated with dust storms in the Sistan region, southeastern Iran

Science.gov (United States)

Kaskaoutis, D. G.; Rashki, A.; Houssos, E. E.; Mofidi, A.; Goto, D.; Bartzokas, A.; Francois, P.; Legrand, M.

2015-07-01

Dust storms are considered natural hazards that seriously affect atmospheric conditions, ecosystems and human health. A key requirement for investigating the dust life cycle is the analysis of the meteorological (synoptic and dynamic) processes that control dust emission, uplift and transport. The present work focuses on examining the synoptic and dynamic meteorological conditions associated with dust-storms in the Sistan region, southeastern Iran during the summer season (June-September) of the years 2001-2012. The dust-storm days (total number of 356) are related to visibility records below 1 km at Zabol meteorological station, located near to the dust source. RegCM4 model simulations indicate that the intense northern Levar wind, the high surface heating and the valley-like characteristics of the region strongly affect the meteorological dynamics and the formation of a low-level jet that are strongly linked with dust exposures. The intra-annual evolution of the dust storms does not seem to be significantly associated with El-Nino Southern Oscillation, despite the fact that most of the dust-storms are related to positive values of Oceanic Nino Index. National Center for Environmental Prediction/National Center for Atmospheric Research reanalysis suggests that the dust storms are associated with low sea-level pressure conditions over the whole south Asia, while at 700 hPa level a trough of low geopotential heights over India along with a ridge over Arabia and central Iran is the common scenario. A significant finding is that the dust storms over Sistan are found to be associated with a pronounced increase of the anticyclone over the Caspian Sea, enhancing the west-to-east pressure gradient and, therefore, the blowing of Levar. Infrared Difference Dust Index values highlight the intensity of the Sistan dust storms, while the SPRINTARS model simulates the dust loading and concentration reasonably well, since the dust storms are usually associated with peaks in model

Mars atmospheric phenomena during major dust storms, as measured at surface

International Nuclear Information System (INIS)

Ryan, J.A.; Henry, R.M.

1979-01-01

Meteorological instrumentation aboard the Viking Mars Landers measures wind, temperature, and pressure. Two global dust storms occurred during northern autumn and winter, observed both by the orbiters and by the landers. The meteorological data from the landers has been analyzed for the period just before first storm arrival to just after second storm arrival, with the objectives being definition of meteorological phenomena during the storm period, determination of those associated with storm and dust arrival, and evaluation of effects on synoptic conditions and the general circulation. Times of dust arrival over the sites could be defined fairly closely from optical and pressure (solar tide) data, and dust arrival was also accompanied by changes in diurnal temperature range, temperature maxima, and temperature minima. The arrivals of the storms at VL-1 were accompanied by significant increase in wind speed and pressure. No such changes were observed at VL-2. It is possible that surface material could have been raised locally at VL-1. Throughout the period except following the second dust storm synoptic picture at VL-2 was one of eastward moving cyclonic and anticyclonic systems. These disappeared following the second storm, a phenomenon which may be related to the storm

Dust storms and their impact on ocean and human health: dust in Earth's atmosphere

Science.gov (United States)

Griffin, Dale W.; Kellog, Christina A.

2004-01-01

Satellite imagery has greatly influenced our understanding of dust activity on a global scale. A number of different satellites such as NASA's Earth-Probe Total Ozone Mapping Spectrometer (TOMS) and Se-viewing Field-of-view Sensor (SeaWiFS) acquire daily global-scale data used to produce imagery for monitoring dust storm formation and movement. This global-scale imagery has documented the frequent transmission of dust storm-derived soils through Earth's atmosphere and the magnitude of many of these events. While various research projects have been undertaken to understand this normal planetary process, little has been done to address its impact on ocean and human health. This review will address the ability of dust storms to influence marine microbial population densities and transport of soil-associated toxins and pathogenic microorganisms to marine environments. The implications of dust on ocean and human health in this emerging scientific field will be discussed.

Characterisation of atmospheric deposited particles during a dust storm in urban areas of Eastern Australia

Energy Technology Data Exchange (ETDEWEB)

Gunawardena, Janaka, E-mail: j.gunawardena@qut.edu.au; Ziyath, Abdul M., E-mail: mohamed.ziyath@qut.edu.au; Bostrom, Thor E., E-mail: t.bostrom@qut.edu.au; Bekessy, Lambert K., E-mail: l.bekessy@qut.edu.au; Ayoko, Godwin A., E-mail: g.ayoko@qut.edu.au; Egodawatta, Prasanna, E-mail: p.egodawatta@qut.edu.au; Goonetilleke, Ashantha, E-mail: a.goonetilleke@qut.edu.au

2013-09-01

The characteristics of dust particles deposited during the 2009 dust storm in the Gold Coast and Brisbane regions of Australia are discussed in this paper. The study outcomes provide important knowledge in relation to the potential impacts of dust storm related pollution on ecosystem health in the context that the frequency of dust storms is predicted to increase due to anthropogenic desert surface modifications and climate change impacts. The investigated dust storm contributed a large fraction of fine particles to the environment with an increased amount of total suspended solids, compared to dry deposition under ambient conditions. Although the dust storm passed over forested areas, the organic carbon content in the dust was relatively low. The primary metals present in the dust storm deposition were aluminium, iron and manganese, which are common soil minerals in Australia. The dust storm deposition did not contain significant loads of nickel, cadmium, copper and lead, which are commonly present in the urban environment. Furthermore, the comparison between the ambient and dust storm chromium and zinc loads suggested that these metals were contributed to the dust storm by local anthropogenic sources. The potential ecosystem health impacts of the 2009 dust storm include, increased fine solids deposition on ground surfaces resulting in an enhanced capacity to adsorb toxic pollutants as well as increased aluminium, iron and manganese loads. In contrast, the ecosystem health impacts related to organic carbon and other metals from dust storm atmospheric deposition are not considered to be significant. - Highlights: • The dust storm contributed a large fraction of fine particles to pollutant build-up. • The dust storm increased TSS, Al, Fe and Mn loads in build-up on ground surfaces. • Dust storm did not significantly increase TOC, Ni, Cu, Pb and Cd loads in build-up. • Cr and Zn in dust storm deposition were contributed by local anthropogenic sources.

Characterisation of atmospheric deposited particles during a dust storm in urban areas of Eastern Australia

International Nuclear Information System (INIS)

Gunawardena, Janaka; Ziyath, Abdul M.; Bostrom, Thor E.; Bekessy, Lambert K.; Ayoko, Godwin A.; Egodawatta, Prasanna; Goonetilleke, Ashantha

2013-01-01

The characteristics of dust particles deposited during the 2009 dust storm in the Gold Coast and Brisbane regions of Australia are discussed in this paper. The study outcomes provide important knowledge in relation to the potential impacts of dust storm related pollution on ecosystem health in the context that the frequency of dust storms is predicted to increase due to anthropogenic desert surface modifications and climate change impacts. The investigated dust storm contributed a large fraction of fine particles to the environment with an increased amount of total suspended solids, compared to dry deposition under ambient conditions. Although the dust storm passed over forested areas, the organic carbon content in the dust was relatively low. The primary metals present in the dust storm deposition were aluminium, iron and manganese, which are common soil minerals in Australia. The dust storm deposition did not contain significant loads of nickel, cadmium, copper and lead, which are commonly present in the urban environment. Furthermore, the comparison between the ambient and dust storm chromium and zinc loads suggested that these metals were contributed to the dust storm by local anthropogenic sources. The potential ecosystem health impacts of the 2009 dust storm include, increased fine solids deposition on ground surfaces resulting in an enhanced capacity to adsorb toxic pollutants as well as increased aluminium, iron and manganese loads. In contrast, the ecosystem health impacts related to organic carbon and other metals from dust storm atmospheric deposition are not considered to be significant. - Highlights: • The dust storm contributed a large fraction of fine particles to pollutant build-up. • The dust storm increased TSS, Al, Fe and Mn loads in build-up on ground surfaces. • Dust storm did not significantly increase TOC, Ni, Cu, Pb and Cd loads in build-up. • Cr and Zn in dust storm deposition were contributed by local anthropogenic sources

The relationship between the Asian dust and Arctic Oscillation: An observational investigation

Science.gov (United States)

Lee, Y.; Kim, J.; Cho, H.

2009-12-01

The Arctic Oscillation (AO) represents the leading empirical orthogonal function of winter sea level pressure (SLP) fields, which resembles North Atlantic Oscillation, but has a more zonally symmetric structure (Thompson and Wallace, 1998; Wallace, 2000; Wu and Wang, 2002). This primary mode of the internal dynamics in the atmosphere predominates the Extratropical Northern Hemisphere circulation from surface to the lower stratosphere showing an equivalent barotropic structure during cold season(November-April) (Thompson and Wallace, 2000). Also, the Asian dust storms show strong interannual variation (Sun et al., 2001; Yoshino, 2002; Zhao et al., 2006; Hara et al., 2006), which are suggested to be associated with climate indices. Therefore, the purpose of this study is to identify the possible connection for the AO and the Asian dust emission during periods from late winter to spring, based on the observational investigations. In order to examine these complex associations closely, the Aerosol Index (AI) from Total Ozone Mapping Spectrometer (TOMS) are used starting from November 1978 to December 1999, except for data pause from May 1993 to August 1996. SLP and geopotential height at 500hPa (Z500) monthly fields are derived from the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalyses (1958-2001). Also, source regions of Asian dust are mainly focused on three source areas, including the Taklimakan Desert (R1), Badain Jaran Desert (R2), and Mongolia (R3) in this study. In composite study during different phases of AO, the AO exhibits a “negative phase” with relatively high pressure over the polar region and low pressure at mid-latitudes (about 45 degrees North). In strong “negative phase” of AO, decrease of AO is found to be associated with decreases of local tropospheric temperature, U-wind, and geopotential height and strong north-south gradients over the source regions of Asian dust. Therefore, we also notice that a negative index phase

The Spatial Variation of Dust Particulate Matter Concentrations during Two Icelandic Dust Storms in 2015

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Pavla Dagsson-Waldhauserova

2016-06-01

Full Text Available Particulate matter mass concentrations and size fractions of PM1, PM2.5, PM4, PM10, and PM15 measured in transversal horizontal profile of two dust storms in southwestern Iceland are presented. Images from a camera network were used to estimate the visibility and spatial extent of measured dust events. Numerical simulations were used to calculate the total dust flux from the sources as 180,000 and 280,000 tons for each storm. The mean PM15 concentrations inside of the dust plumes varied from 10 to 1600 µg·m−3 (PM10 = 7 to 583 µg·m−3. The mean PM1 concentrations were 97–241 µg·m−3 with a maximum of 261 µg·m−3 for the first storm. The PM1/PM2.5 ratios of >0.9 and PM1/PM10 ratios of 0.34–0.63 show that suspension of volcanic materials in Iceland causes air pollution with extremely high PM1 concentrations, similar to polluted urban areas in Europe or Asia. Icelandic volcanic dust consists of a higher proportion of submicron particles compared to crustal dust. Both dust storms occurred in relatively densely inhabited areas of Iceland. First results on size partitioning of Icelandic dust presented here should challenge health authorities to enhance research in relation to dust and shows the need for public dust warning systems.

Effect of dust storms on FSO communications links

KAUST Repository

Esmail, Maged Abdullah; Fathallah, Habib; Alouini, Mohamed-Slim

2017-01-01

In literature, there is a lake of information about free space optic (FSO) systems' performance in arid and semi-arid areas that are prone to frequent dust storms. Therefore, in this paper, we investigate the performance of FSO links under dust storm conditions. We aim to determine the limits and capabilities of such systems in this harsh environment. To achieve this goal, we use some performance metrics including signal-to-noise (SNR) ratio, bit error rate (BER), and channel capacity. The results show that dust is a rough impairment that causes link drop under low visibility range. Moreover, we found that the system performance can be improved by using short segments or multi-hop system. Furthermore, the results show negligible improvement in system performance under dense dust. The comparison of fog and dust impairments show that dust introduces much higher attenuation than fog. Therefore, dust can be considered as the ultimate impairment for FSO links.

Effect of dust storms on FSO communications links

KAUST Repository

Esmail, Maged Abdullah

2017-05-18

In literature, there is a lake of information about free space optic (FSO) systems\\' performance in arid and semi-arid areas that are prone to frequent dust storms. Therefore, in this paper, we investigate the performance of FSO links under dust storm conditions. We aim to determine the limits and capabilities of such systems in this harsh environment. To achieve this goal, we use some performance metrics including signal-to-noise (SNR) ratio, bit error rate (BER), and channel capacity. The results show that dust is a rough impairment that causes link drop under low visibility range. Moreover, we found that the system performance can be improved by using short segments or multi-hop system. Furthermore, the results show negligible improvement in system performance under dense dust. The comparison of fog and dust impairments show that dust introduces much higher attenuation than fog. Therefore, dust can be considered as the ultimate impairment for FSO links.

Trajectory Calculation as Forecasting Support Tool for Dust Storms

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Sultan Al-Yahyai

2014-01-01

Full Text Available In arid and semiarid regions, dust storms are common during windy seasons. Strong wind can blow loose sand from the dry surface. The rising sand and dust is then transported to other places depending on the wind conditions (speed and direction at different levels of the atmosphere. Considering dust as a moving object in space and time, trajectory calculation then can be used to determine the path it will follow. Trajectory calculation is used as a forecast supporting tool for both operational and research activities. Predefined dust sources can be identified and the trajectories can be precalculated from the Numerical Weather Prediction (NWP forecast. In case of long distance transported dust, the tool should allow the operational forecaster to perform online trajectory calculation. This paper presents a case study for using trajectory calculation based on NWP models as a forecast supporting tool in Oman Meteorological Service during some dust storm events. Case study validation results showed a good agreement between the calculated trajectories and the real transport path of the dust storms and hence trajectory calculation can be used at operational centers for warning purposes.

Interannual Similarity in the Martian Atmosphere During the Dust Storm Season

Science.gov (United States)

Kass, D. M.; Kleinboehl, A.; McCleese, D. J.; Schofield, J. T.; Smith, M. D.

2016-01-01

We find that during the dusty season on Mars (southern spring and summer) of years without a global dust storm there are three large regional-scale dust storms. The storms are labeled A, B, and C in seasonal order. This classification is based on examining the zonal mean 50 Pa (approximately 25 km) daytime temperature retrievals from TES/MGS and MCS/MRO over 6 Mars Years. Regional-scale storms are defined as events where the temperature exceeds 200 K. Examining the MCS dust field at 50 Pa indicates that warming in the Southern Hemisphere is dominated by direct heating, while northern high latitude warming is a dynamical response. A storms are springtime planet encircling Southern Hemisphere events. B storms are southern polar events that begin near perihelion and last through the solstice. C storms are southern summertime events starting well after the end of the B storm. C storms show the most interannual variability.

Mortality associated with particulate concentration and Asian dust storms in Metropolitan Taipei

Science.gov (United States)

Wang, Yu-Chun; Lin, Yu-Kai

2015-09-01

This study evaluates mortality risks from all causes, circulatory diseases, and respiratory diseases associated with particulate matter (PM10 and PM2.5) concentrations and Asian dust storms (ADS) from 2000 to 2008 in Metropolitan Taipei. This study uses a distributed lag non-linear model with Poisson distribution to estimate the cumulative 5-day (lags 0-4) relative risks (RRs) and confidence intervals (CIs) of cause-specific mortality associated with daily PM10 and PM2.5 concentrations, as well as ADS, for total (all ages) and elderly (≥65 years) populations based on study periods (ADS frequently inflicted period: 2000-2004; and less inflicted period: 2005-2008). Risks associated with ADS characteristics, including inflicted season (winter and spring), strength (the ratio of stations with Pollutant Standard Index >100 is increase in PM10 from 10 μg/m3 to 50 μg/m3 was associated with increased all-cause mortality risk with cumulative 5-day RR of 1.10 (95% CI: 1.04, 1.17) for the total population and 1.10 (95% CI: 1.02, 1.18) for elders. Mortality from circulatory diseases for the elderly was related to increased PM2.5 from 5 μg/m3 to 30 μg/m3, with cumulative 5-day RR of 1.21 (95% CI: 1.02, 1.44) from 2005 to 2008. Compared with normal days, the mortality from all causes and circulatory diseases for the elderly population was associated with winter ADS with RRs of 1.05 (95% CI: 1.01, 1.08) and 1.08 (95% CI: 1.01, 1.15), respectively. Moreover, all-cause mortality was associated with shorter and less area-affected ADS with an RR of 1.04 for total and elderly populations from 2000 to 2004. Population health risk differed not only with PM concentration but also with ADS characteristics.

The Role of Jet Adjustment Processes in Subtropical Dust Storms

Science.gov (United States)

Pokharel, Ashok Kumar; Kaplan, Michael L.; Fiedler, Stephanie

2017-11-01

Meso-α/β/γ scale atmospheric processes of jet dynamics responsible for generating Harmattan, Saudi Arabian, and Bodélé Depression dust storms are analyzed with observations and high-resolution modeling. The analysis of the role of jet adjustment processes in each dust storm shows similarities as follows: (1) the presence of a well-organized baroclinic synoptic scale system, (2) cross mountain flows that produced a leeside inversion layer prior to the large-scale dust storm, (3) the presence of thermal wind imbalance in the exit region of the midtropospheric jet streak in the lee of the respective mountains shortly after the time of the inversion formation, (4) dust storm formation accompanied by large magnitude ageostrophic isallobaric low-level winds as part of the meso-β scale adjustment process, (5) substantial low-level turbulence kinetic energy (TKE), and (6) emission and uplift of mineral dust in the lee of nearby mountains. The thermally forced meso-γ scale adjustment processes, which occurred in the canyons/small valleys, may have been the cause of numerous observed dust streaks leading to the entry of the dust into the atmosphere due to the presence of significant vertical motion and TKE generation. This study points to the importance of meso-β to meso-γ scale adjustment processes at low atmospheric levels due to an imbalance within the exit region of an upper level jet streak for the formation of severe dust storms. The low level TKE, which is one of the prerequisites to deflate the dust from the surface, cannot be detected with the low resolution data sets; so our results show that a high spatial resolution is required for better representing TKE as a proxy for dust emission.

Effect of exposure to an Asian dust storm on fractional exhaled nitric oxide in adult asthma patients in Western Japan.

Science.gov (United States)

Watanabe, Masanari; Kurai, Jun; Sano, Hiroyuki; Shimizu, Eiji

2015-01-01

Epidemiological investigations indicate that an Asian dust storm (ADS) can aggravate respiratory disorders. However, the effects of ADS on airway inflammation remain unclear. The aim of this study was to investigate the association of exposure to ADS with airway inflammation. The subjects were 33 adult patients with asthma who measured daily peak flow expiratory (PEF) from March to May 2012. Fractional exhaled nitric oxide (FeNO) was measured before and after ADS. The FeNO values were 13.8±13.7 ppb before the ADS and 20.3±19.0 ppb after the ADS, with no significant difference. There was also no significant association of PEF with ADS exposure. However, the increase of FeNO after ADS exposure was proportional to the decrease of PEF (R=-0.78, P<0.0001). These results suggest that airway inflammation aggravated by ADS exposure may induce a decrease in pulmonary function in some adult patients with asthma.

Dust storm detection using random forests and physical-based ...

Indian Academy of Sciences (India)

arid areas of the Middle. East. Due to the influences of dust aerosols on climate and human daily activities, dust detection plays a crucial role in environmental and climatic studies. Detection of dust storms is critical to accurately under- stand dust ...

Impact of Asian Dust on Climate and Air Quality

Science.gov (United States)

Chin, Mian; Tan, Qian; Diehl, Thomas; Yu, Hongbin

2010-01-01

Dust generated from Asian permanent desert and desertification areas can be efficiently transported around the globe, making significant radiative impact through their absorbing and scattering solar radiation and through their deposition on snow and ice to modify the surface albedo. Asian dust is also a major concern of surface air quality not only in the source and immediate downwind regions but also areas thousands of miles away across the Pacific. We present here a global model, GOCART, analysis of data from satellite remote sensing instrument (MODIS, MISR, CALIPSO, OMI) and other observations on Asian dust sources, transport, and deposition, and use the model to assess the Asian dust impact on global climate and air quality.

The impact of dust storms on the Arabian Peninsula and the Red Sea

KAUST Repository

Jish Prakash, P.

2015-01-12

Located in the dust belt, the Arabian Peninsula is a major source of atmospheric dust. Frequent dust outbreaks and some 15 to 20 dust storms per year have profound effects on all aspects of human activity and natural processes in this region. To quantify the effect of severe dust events on radiation fluxes and regional climate characteristics, we simulated the storm that occurred from 18 to 20 March 2012 using a regional weather research forecast model fully coupled with the chemistry/aerosol module (WRF–Chem). This storm swept over a remarkably large area affecting the entire Middle East, northeastern Africa, Afghanistan, and Pakistan. It was caused by a southward propagating cold front, and the associated winds activated the dust production in river valleys of the lower Tigris and Euphrates in Iraq; the coastal areas in Kuwait, Iran, and the United Arab Emirates; the Rub al Khali, An Nafud, and Ad Dahna deserts; and along the Red Sea coast on the west side of the Arabian Peninsula. Our simulation results compare well with available ground-based and satellite observations. We estimate the total amount of dust generated by the storm to have reached 94 Mt. Approximately 78% of this dust was deposited within the calculation domain. The Arabian Sea and Persian Gulf received 5.3 Mt and the Red Sea 1.2 Mt of dust. Dust particles bring nutrients to marine ecosystems, which is especially important for the oligotrophic Northern Red Sea. However, their contribution to the nutrient balance in the Red Sea remains largely unknown. By scaling the effect of one storm to the number of dust storms observed annually over the Red Sea, we estimate the annual dust deposition to the Red Sea, associated with major dust storms, to be 6 Mt.

The impact of dust storms on the Arabian Peninsula and the Red Sea

KAUST Repository

Jish Prakash, P.; Stenchikov, Georgiy L.; Kalenderski, Stoitchko; Osipov, Sergey; Bangalath, Hamza Kunhu

2015-01-01

Located in the dust belt, the Arabian Peninsula is a major source of atmospheric dust. Frequent dust outbreaks and some 15 to 20 dust storms per year have profound effects on all aspects of human activity and natural processes in this region. To quantify the effect of severe dust events on radiation fluxes and regional climate characteristics, we simulated the storm that occurred from 18 to 20 March 2012 using a regional weather research forecast model fully coupled with the chemistry/aerosol module (WRF–Chem). This storm swept over a remarkably large area affecting the entire Middle East, northeastern Africa, Afghanistan, and Pakistan. It was caused by a southward propagating cold front, and the associated winds activated the dust production in river valleys of the lower Tigris and Euphrates in Iraq; the coastal areas in Kuwait, Iran, and the United Arab Emirates; the Rub al Khali, An Nafud, and Ad Dahna deserts; and along the Red Sea coast on the west side of the Arabian Peninsula. Our simulation results compare well with available ground-based and satellite observations. We estimate the total amount of dust generated by the storm to have reached 94 Mt. Approximately 78% of this dust was deposited within the calculation domain. The Arabian Sea and Persian Gulf received 5.3 Mt and the Red Sea 1.2 Mt of dust. Dust particles bring nutrients to marine ecosystems, which is especially important for the oligotrophic Northern Red Sea. However, their contribution to the nutrient balance in the Red Sea remains largely unknown. By scaling the effect of one storm to the number of dust storms observed annually over the Red Sea, we estimate the annual dust deposition to the Red Sea, associated with major dust storms, to be 6 Mt.

Contribution of Asian dust to atmospheric deposition of radioactive cesium (137Cs)

International Nuclear Information System (INIS)

Fukuyama, Taijiro; Fujiwara, Hideshi

2008-01-01

Both Asian dust (kosa) transported from the East Asian continent and locally suspended dust near monitoring sites contribute to the observed atmospheric deposition of 137 Cs in Japan. To estimate the relative contribution of these dust phenomena to the total 137 Cs deposition, we monitored weekly deposition of mineral particles and 137 Cs in spring. Deposition of 137 Cs from a single Asian dust event was 62.3 mBq m -2 and accounted for 67% of the total 137 Cs deposition during the entire monitoring period. Furthermore, we found high 137 Cs specific activity in the Asian dust deposition sample. Although local dust events contributed to 137 Cs deposition, their contribution was considerably smaller than that of Asian dust. We conclude that the primary source of atmospheric 137 Cs in Japan is dust transported from the East Asian continent

Simulation and analysis of synoptic scale dust storms over the Arabian Peninsula

Science.gov (United States)

Beegum, S. Naseema; Gherboudj, Imen; Chaouch, Naira; Temimi, Marouane; Ghedira, Hosni

2018-01-01

Dust storms are among the most severe environmental problems in arid and semi-arid regions of the world. The predictability of seven dust events, viz. D1: April 2-4, 2014; D2: February 23-24, 2015; D3: April 1-3, 2015; D4: March 26-28, 2016; D5: August 3-5, 2016; D6: March 13-14, 2017 and D7:March 19-21, 2017, are investigated over the Arabian Peninsula using a regionally adapted chemistry transport model CHIMERE coupled with the Weather Research and Forecast (WRF) model. The hourly forecast products of particulate matter concentrations (PM10) and aerosol optical depths (AOD) are compared against both satellite-based (MSG/SEVRI RGB dust, MODIS Deep Blue Aerosol Optical Depth: DB-AOD, Ozone Monitoring Instrument observed UV Aerosol Absorption Index: OMI-AI) and ground-based (AERONET AOD) remote sensing products. The spatial pattern and the time series of the simulations show good agreement with the observations in terms of the dust intensity as well as the spatiotemporal distribution. The causative mechanisms of these dust events are identified by the concurrent analyses of the meteorological data. From these seven storms, five are associated with synoptic scale meteorological processes, such as prefrontal storms (D1 and D7), postfrontal storms of short (D2), and long (D3) duration types, and a summer shamal storm (D6). However, the storms D4 and D6 are partly associated with mesoscale convective type dust episodes known as haboobs. The socio-economic impacts of the dust events have been assessed by estimating the horizontal visibility, air quality index (AQI), and the dust deposition flux (DDF) from the forecasted dust concentrations. During the extreme dust events, the horizontal visibility drops to near-zero values co-occurred withhazardous levels of AQI and extremely high dust deposition flux (250 μg cm- 2 day- 1).

Martian dust storms as a possible sink of atmospheric methane

Science.gov (United States)

Farrell, W. M.; Delory, G. T.; Atreya, S. K.

2006-11-01

Recent laboratory tests, analog studies and numerical simulations all suggest that Martian dust devils and larger dusty convective storms generate and maintain large-scale electric fields. Such expected E-fields will have the capability to create significant electron drift motion in the collisional gas and to form an extended high energy (u $\\gg$ kT) electron tail in the distribution. We demonstrate herein that these energetic electrons are capable of dissociating any trace CH4 in the ambient atmosphere thereby acting as an atmospheric sink of this important gas. We demonstrate that the methane destruction rate increases by a factor of 1012 as the dust storm E-fields, E, increase from 5 to 25 kV/m, resulting in an apparent decrease in methane stability from ~ 1010 sec to a value of ~1000 seconds. While destruction in dust storms is severe, the overall methane lifetime is expected to decrease only moderately due to recycling of products, heterogeneous effects from localized sinks, etc. We show further evidence that the electrical activity anticipated in Martian dust storms creates a new harsh electro-chemical environment.

Identification of dust storm source areas in West Asia using multiple environmental datasets.

Science.gov (United States)

Cao, Hui; Amiraslani, Farshad; Liu, Jian; Zhou, Na

2015-01-01

Sand and Dust storms are common phenomena in arid and semi-arid areas. West Asia Region, especially Tigris-Euphrates alluvial plain, has been recognized as one of the most important dust source areas in the world. In this paper, a method is applied to extract SDS (Sand and Dust Storms) sources in West Asia region using thematic maps, climate and geography, HYSPLIT model and satellite images. Out of 50 dust storms happened during 2000-2013 and collected in form of MODIS images, 27 events were incorporated as demonstrations of the simulated trajectories by HYSPLIT model. Besides, a dataset of the newly released Landsat images was used as base-map for the interpretation of SDS source regions. As a result, six main clusters were recognized as dust source areas. Of which, 3 clusters situated in Tigris-Euphrates plain were identified as severe SDS sources (including 70% dust storms in this research). Another cluster in Sistan plain is also a potential source area. This approach also confirmed six main paths causing dust storms. These paths are driven by the climate system including Siberian and Polar anticyclones, monsoon from Indian Subcontinent and depression from north of Africa. The identification of SDS source areas and paths will improve our understandings on the mechanisms and impacts of dust storms on socio-economy and environment of the region. Copyright © 2014 Elsevier B.V. All rights reserved.

Dust Storm Hits Canary Islands

Science.gov (United States)

2002-01-01

A thick pall of sand and dust blew out from the Sahara Desert over the Atlantic Ocean yesterday (January 6, 2002), engulfing the Canary Islands in what has become one of the worst sand storms ever recorded there. In this scene, notice how the dust appears particularly thick in the downwind wake of Tenerife, the largest of the Canary Islands. Perhaps the turbulence generated by the air currents flowing past the island's volcanic peaks is churning the dust back up into the atmosphere, rather than allowing it to settle toward the surface. This true-color image was captured by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra satellite, on January 7, 2002. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

Surface observation of sand and dust storm in East Asia and its application in CUACE/Dust

Directory of Open Access Journals (Sweden)

Y. Q. Wang

2008-02-01

Full Text Available The spatial-temporal distributions and sources of sand and dust storm (SDS in East Asia from 2001 to 2006 were investigated on the basis of visibility and PM₁₀ data from the routine SDS and weather monitoring networks run by CMA (China Meteorological Administration. A power functional relationships between PM₁₀ and visibility was found among various regions generally with a good correlation (r²=0.90, especially in Asian SDS source regions. In addition, three SDS occurrence centers, i.e. western China, Mongolia and northern China, were identified with the Mongolia source contributing more dust to the downwind areas including Korea and Japan than other two sources. Generally, high PM₁₀ concentrations were observed in most areas of northern China. The highest value was obtained in the center of western China with a spring daily mean value of 876 μgm⁻³, and the value in other source regions exceeds 200 μgm⁻³. These data sets together with the satellite observations in China form the main observation database for the evaluation and data assimilation of CUACE/Dust system – an operational SDS forecasting system for East Asia.

Dust storm, northern Mexico

Science.gov (United States)

1983-01-01

This large dust storm along the left side of the photo, covers a large portion of the state of Coahuila, Mexico (27.5N, 102.0E). The look angle of this oblique photo is from the south to the north. In the foreground is the Sierra Madre Oriental in the states Coahuila and Nuevo Leon with the Rio Grande River, Amistad Reservoir and Texas in the background.

Accelerating Dust Storm Simulation by Balancing Task Allocation in Parallel Computing Environment

Science.gov (United States)

Gui, Z.; Yang, C.; XIA, J.; Huang, Q.; YU, M.

2013-12-01

Dust storm has serious negative impacts on environment, human health, and assets. The continuing global climate change has increased the frequency and intensity of dust storm in the past decades. To better understand and predict the distribution, intensity and structure of dust storm, a series of dust storm models have been developed, such as Dust Regional Atmospheric Model (DREAM), the NMM meteorological module (NMM-dust) and Chinese Unified Atmospheric Chemistry Environment for Dust (CUACE/Dust). The developments and applications of these models have contributed significantly to both scientific research and our daily life. However, dust storm simulation is a data and computing intensive process. Normally, a simulation for a single dust storm event may take several days or hours to run. It seriously impacts the timeliness of prediction and potential applications. To speed up the process, high performance computing is widely adopted. By partitioning a large study area into small subdomains according to their geographic location and executing them on different computing nodes in a parallel fashion, the computing performance can be significantly improved. Since spatiotemporal correlations exist in the geophysical process of dust storm simulation, each subdomain allocated to a node need to communicate with other geographically adjacent subdomains to exchange data. Inappropriate allocations may introduce imbalance task loads and unnecessary communications among computing nodes. Therefore, task allocation method is the key factor, which may impact the feasibility of the paralleling. The allocation algorithm needs to carefully leverage the computing cost and communication cost for each computing node to minimize total execution time and reduce overall communication cost for the entire system. This presentation introduces two algorithms for such allocation and compares them with evenly distributed allocation method. Specifically, 1) In order to get optimized solutions, a

An automated and integrated framework for dust storm detection based on ogc web processing services

Science.gov (United States)

Xiao, F.; Shea, G. Y. K.; Wong, M. S.; Campbell, J.

2014-11-01

Dust storms are known to have adverse effects on public health. Atmospheric dust loading is also one of the major uncertainties in global climatic modelling as it is known to have a significant impact on the radiation budget and atmospheric stability. The complexity of building scientific dust storm models is coupled with the scientific computation advancement, ongoing computing platform development, and the development of heterogeneous Earth Observation (EO) networks. It is a challenging task to develop an integrated and automated scheme for dust storm detection that combines Geo-Processing frameworks, scientific models and EO data together to enable the dust storm detection and tracking processes in a dynamic and timely manner. This study develops an automated and integrated framework for dust storm detection and tracking based on the Web Processing Services (WPS) initiated by Open Geospatial Consortium (OGC). The presented WPS framework consists of EO data retrieval components, dust storm detecting and tracking component, and service chain orchestration engine. The EO data processing component is implemented based on OPeNDAP standard. The dust storm detecting and tracking component combines three earth scientific models, which are SBDART model (for computing aerosol optical depth (AOT) of dust particles), WRF model (for simulating meteorological parameters) and HYSPLIT model (for simulating the dust storm transport processes). The service chain orchestration engine is implemented based on Business Process Execution Language for Web Service (BPEL4WS) using open-source software. The output results, including horizontal and vertical AOT distribution of dust particles as well as their transport paths, were represented using KML/XML and displayed in Google Earth. A serious dust storm, which occurred over East Asia from 26 to 28 Apr 2012, is used to test the applicability of the proposed WPS framework. Our aim here is to solve a specific instance of a complex EO data

Oxidant enhancement in martian dust devils and storms: storm electric fields and electron dissociative attachment.

Science.gov (United States)

Delory, Gregory T; Farrell, William M; Atreya, Sushil K; Renno, Nilton O; Wong, Ah-San; Cummer, Steven A; Sentman, Davis D; Marshall, John R; Rafkin, Scot C R; Catling, David C

2006-06-01

Laboratory studies, numerical simulations, and desert field tests indicate that aeolian dust transport can generate atmospheric electricity via contact electrification or "triboelectricity." In convective structures such as dust devils and dust storms, grain stratification leads to macroscopic charge separations and gives rise to an overall electric dipole moment in the aeolian feature, similar in nature to the dipolar electric field generated in terrestrial thunderstorms. Previous numerical simulations indicate that these storm electric fields on Mars can approach the ambient breakdown field strength of approximately 25 kV/m. In terrestrial dust phenomena, potentials ranging from approximately 20 to 160 kV/m have been directly measured. The large electrostatic fields predicted in martian dust devils and storms can energize electrons in the low pressure martian atmosphere to values exceeding the electron dissociative attachment energy of both CO2 and H2O, which results in the formation of the new chemical products CO/O- and OH/H-, respectively. Using a collisional plasma physics model, we present calculations of the CO/O- and OH/H- reaction and production rates. We demonstrate that these rates vary geometrically with the ambient electric field, with substantial production of dissociative products when fields approach the breakdown value of approximately 25 kV/m. The dissociation of H2O into OH/H- provides a key ingredient for the generation of oxidants; thus electrically charged dust may significantly impact the habitability of Mars.

Shifts in alpine lakes' ecosystems in Japan driven by increasing Asian dusts

Science.gov (United States)

Tsugeki, N. K.; Tani, Y.; Ueda, S.; Agusa, T.; Toyoda, K.; Kuwae, M.; Oda, H.; Tanabe, S.; Urabe, J.

2011-12-01

Recently in East Asia the amount of fossil fuel combustion have increased with economic growth. It has caused a problem of trans-boundary air pollution in the whole of eastern Asia. Furthermore, Asian dust storms contribute episodically to the global aerosol load. However, the effects of increased Asian dusts on aquatic ecosystems are not well understood. If biologically important nutrients such as nitrogen (N) and phosphorus (P) are transported via air dust, the atmospheric deposition of the dust may have serious impacts on recipient aquatic ecosystems because the biological production is limited by these nutrient elements. A previous report using sedimentary records has evaluated that atmospheric P inputs to the alpine lakes in the United States increased fivefold following the increased western settlement to this country during the nineteenth century. Since P is the most deficient nutrient for production in many lakes increase in P loading through atmospheric deposition of anthropogenically-derived dust might greatly affect the lake ecosystems. We examined fossil pigments and zooplankton remains from Pb-dated sediments taken from a high mountain lake of Hourai-Numa, located in the Towada-Hachimantai National Park of Japan, to uncover historical changes in the phyto- and zooplankton community over the past 100 years. Simultaneously, we measured the biogeochemical variables of TOC, TN, TP, δ13C, δ15N, and 206Pb/207Pb, 208Pb/207Pb in the sediments to identify environmental factors causing such changes. As a result, despite little anthropogenic activities in the watersheds, alpine lakes in Japan Islands increased algal and herbivore plankton biomasses by 3-6 folds for recent years depending on terrestrial the surrounded vegetations and landscape conditions. Biological and biogeochemical proxies recorded in the lake sediments indicate that this eutrophication occurred after the 1990s when P deposition increased due to atmospheric loading transported from Asian

Asian dust storm elevates children's respiratory health risks: a spatiotemporal analysis of children's clinic visits across Taipei (Taiwan.

Directory of Open Access Journals (Sweden)

Hwa-Lung Yu

Full Text Available Concerns have been raised about the adverse impact of Asian dust storms (ADS on human health; however, few studies have examined the effect of these events on children's health. Using databases from the Taiwan National Health Insurance and Taiwan Environmental Protection Agency, this study investigates the documented daily visits of children to respiratory clinics during and after ADS that occurred from 1997 to 2007 among 12 districts across Taipei City by applying a Bayesian structural additive regressive model controlled for spatial and temporal patterns. This study finds that the significantly impact of elevated children's respiratory clinic visits happened after ADS. Five of the seven lagged days had increasing percentages of relative rate, which was consecutively elevated from a 2-day to a 5-day lag by 0.63%∼2.19% for preschool children (i.e., 0∼6 years of age and 0.72%∼3.17% for school children (i.e., 7∼14 years of age. The spatial pattern of clinic visits indicated that geographical heterogeneity was possibly associated with the clinic's location and accessibility. Moreover, day-of-week effects were elevated on Monday, Friday, and Saturday. We concluded that ADS may significantly increase the risks of respiratory diseases consecutively in the week after exposure, especially in school children.

Long-term variability of dust-storms in Iceland

Science.gov (United States)

Dagsson-Waldhauserová, Pavla; Ólafsson, Haraldur; Arnalds, Ólafur

2013-04-01

Iceland is a volcanic island in the North Atlantic Ocean with maritime climate. In spite of moist climate, large areas are with limited vegetation cover where >40% of Iceland is classified with considerable to very severe erosion and 21% of Iceland are volcanic sandy deserts. Natural emissions from these sources influenced by strong winds affect not only regional air quality in Iceland ("Reykjavik haze") but dust particles are transported over the Atlantic ocean and Arctic Ocean > 1000 km at times. The study places Icelandic dust production area into international perspective, present long term frequency of dust storm events in NE Iceland, and estimate dust aerosol concentrations during reported dust events. Meteorological observations with dust presence codes and related visibility were used to identify the frequency and the long-term changes in dust production in NE Iceland. There were annually 16.4 days on average with reported dust observations on weather stations within the NE erosion area, indicating extreme dust plume activity and erosion within the NE deserts, even though the area is covered with snow during the major part of winter. During the 2000s the highest occurrence of dust events in six decades was reported. We have measured saltation and aeolian transport during dust/volcanic ash storms in Iceland which give some of the most intense wind erosion events ever measured. Icelandic dust affects the ecosystems over much of Iceland and causes regional haze. It is likely to affect the ecosystems of the oceans around Iceland, and it brings dust that lowers the albedo of the Icelandic glaciers, increasing melt-off due to global warming. The study indicates that Icelandic dust is not only a substantial source for regional air pollution, but may be considered to contribute to the Arctic haze phenomena and Arctic air pollution.

Development of High-Resolution Dynamic Dust Source Function - A Case Study with a Strong Dust Storm in a Regional Model

Science.gov (United States)

Kim, Dongchul; Chin, Mian; Kemp, Eric M.; Tao, Zhining; Peters-Lidard, Christa D.; Ginoux, Paul

2017-01-01

A high-resolution dynamic dust source has been developed in the NASA Unified-Weather Research and Forecasting (NU-WRF) model to improve the existing coarse static dust source. In the new dust source map, topographic depression is in 1-km resolution and surface bareness is derived using the Normalized Difference Vegetation Index (NDVI) data from Moderate Resolution Imaging Spectroradiometer (MODIS). The new dust source better resolves the complex topographic distribution over the Western United States where its magnitude is higher than the existing, coarser resolution static source. A case study is conducted with an extreme dust storm that occurred in Phoenix, Arizona in 0203 UTC July 6, 2011. The NU-WRF model with the new high-resolution dynamic dust source is able to successfully capture the dust storm, which was not achieved with the old source identification. However the case study also reveals several challenges in reproducing the time evolution of the short-lived, extreme dust storm events.

Development of High-Resolution Dynamic Dust Source Function -A Case Study with a Strong Dust Storm in a Regional Model.

Science.gov (United States)

Kim, Dongchul; Chin, Mian; Kemp, Eric M; Tao, Zhining; Peters-Lidard, Christa D; Ginoux, Paul

2017-06-01

A high-resolution dynamic dust source has been developed in the NASA Unified-Weather Research and Forecasting (NU-WRF) model to improve the existing coarse static dust source. In the new dust source map, topographic depression is in 1-km resolution and surface bareness is derived using the Normalized Difference Vegetation Index (NDVI) data from Moderate Resolution Imaging Spectroradiometer (MODIS). The new dust source better resolves the complex topographic distribution over the Western United States where its magnitude is higher than the existing, coarser resolution static source. A case study is conducted with an extreme dust storm that occurred in Phoenix, Arizona in 02-03 UTC July 6, 2011. The NU-WRF model with the new high-resolution dynamic dust source is able to successfully capture the dust storm, which was not achieved with the old source identification. However the case study also reveals several challenges in reproducing the time evolution of the short-lived, extreme dust storm events.

Paracas dust storms: Sources, trajectories and associated meteorological conditions

Science.gov (United States)

Briceño-Zuluaga, F.; Castagna, A.; Rutllant, J. A.; Flores-Aqueveque, V.; Caquineau, S.; Sifeddine, A.; Velazco, F.; Gutierrez, D.; Cardich, J.

2017-09-01

Dust storms that develop along the Pisco-Ica desert in Southern Peru, locally known as ;Paracas; winds have ecological, health and economic repercussions. Here we identify dust sources through MODIS (Moderate Resolution Imaging Spectroradiometer) imagery and analyze HYSPLIT (Hybrid Single Particles Lagrangian Integrated Trajectory) model trajectories and dispersion patterns, along with concomitant synoptic-scale meteorological conditions from National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis (NCEP/NCAR). Additionally, surface pressure data from the hourly METeorological Aerodrome Report (METAR) at Arica (18.5°S, 70.3°W) and Pisco (13.7°S, 76.2°W) were used to calculate Alongshore (sea-level) Pressure Gradient (APG) anomalies during Paracas dust storms, their duration and associated wind-speeds and wind directions. This study provides a review on the occurrence and strength of the Paracas dust storms as reported in the Pisco airfield for five-year period and their correspondence with MODIS true-color imagery in terms of dust-emission source areas. Our results show that most of the particle fluxes moving into the Ica-Pisco desert area during Paracas wind events originate over the coastal zone, where strong winds forced by steep APGs develop as the axis of a deep mid-troposphere trough sets in along north-central Chile. Direct relationships between Paracas wind intensity, number of active dust-emission sources and APGs are also documented, although the scarcity of simultaneous METAR/MODIS data for clearly observed MODIS dust plumes prevents any significant statistical inference. Synoptic-scale meteorological composites from NCEP/NCAR reanalysis data show that Paracas wind events (steep APGs) are mostly associated with the strengthening of anticyclonic conditions in northern Chile, that can be attributed to cold air advection associated with the incoming trough. Compared to the MODIS images, HYSPLIT outputs were able

Satellite Monitoring of Vegetation Response to Precipitation and Dust Storm Outbreaks in Gobi Desert Regions

Directory of Open Access Journals (Sweden)

Yuki Sofue

2018-02-01

Full Text Available Recently, droughts have become widespread in the Northern Hemisphere, including in Mongolia. The ground surface condition, particularly vegetation coverage, affects the occurrence of dust storms. The main sources of dust storms in the Asian region are the Taklimakan and Mongolian Gobi desert regions. In these regions, precipitation is one of the most important factors for growth of plants especially in arid and semi-arid land. The purpose of this study is to clarify the relationship between precipitation and vegetation cover dynamics over 29 years in the Gobi region. We compared the patterns between precipitation and Normalized Difference Vegetation Index (NDVI for a period of 29 years. The precipitation and vegetation datasets were examined to investigate the trends during 1985–2013. Cross correlation analysis between the precipitation and the NDVI anomalies was performed. Data analysis showed that the variations of NDVI anomalies in the east region correspond well with the precipitation anomalies during this period. However, in the southwest region of the Gobi region, the NDVI had decreased regardless of the precipitation amount, especially since 2010. This result showed that vegetation in this region was more degraded than in the other areas.

Radio Emissions from Electrical Activity in Martian Dust Storms

Science.gov (United States)

Majid, W.; Arabshahi, S.; Kocz, J.; Schulter, T.; White, L.

2017-12-01

Dust storms on Mars are predicted to be capable of producing electrostatic fields and discharges, even larger than those in dust storms on Earth. There are three key elements in the characterization of Martian electrostatic discharges: dependence on Martian environmental conditions, event rate, and the strength of the generated electric fields. The detection and characterization of electric activity in Martian dust storms has important implications for habitability, and preparations for human exploration of the red planet. Furthermore, electrostatic discharges may be linked to local chemistry and plays an important role in the predicted global electrical circuit. Because of the continuous Mars telecommunication needs of NASA's Mars-based assets, the Deep Space Network (DSN) is the only facility in the world that combines long term, high cadence, observing opportunities with large sensitive telescopes, making it a unique asset worldwide in searching for and characterizing electrostatic activity from large scale convective dust storms at Mars. We will describe a newly inaugurated program at NASA's Madrid Deep Space Communication Complex to carry out a long-term monitoring campaign to search for and characterize the entire Mars hemisphere for powerful discharges during routine tracking of spacecraft at Mars on an entirely non-interfering basis. The ground-based detections will also have important implications for the design of a future instrument that could make similar in-situ measurements from orbit or from the surface of Mars, with far greater sensitivity and duty cycle, opening up a new window in our understanding of the Martian environment.

Activation analysis of deposited dust brought to Israel by dust storms

International Nuclear Information System (INIS)

Ganor, E.; Tal, A.; Donagi, A.

1975-01-01

The determination of dust particles deposited in Jerusalem during regional dust storms was carried out by polarized microscopy, X-ray analysis and atomic absorption measurements. These analyses showed the presence of particles of quartz, calcite, dolomite, feldspar, halite, kaolinite, montmorillonite, epidote, tourmaline, glauconite, illite and other heavy minerals. The aims of the present study were to apply activation analysis for the determination of element composition in dust samples; to compare the results obtained by activation analysis with those obtained by other methods, i.e. chemical analysis, polarized microscopy and X-ray analysis. The results obtained by the various methods were in good agreement. (B.G.)

Development of a Severe Sand-dust Storm Model and its Application to Northwest China

International Nuclear Information System (INIS)

Zhang Xiaoling; Cheng, Linsheng; Chung, Yong-Seung

2003-01-01

A very strong sand-dust storm occurred on 5 May, 1993 in Northwest China. In order to give a detailed description of the evolution of a mesoscale system along with the heavy sand-dust storm, a complex model including improved physical processes and a radiation parameterization scheme was developed based on a simulation model. The improved model introduced a sand-dust transport equation as well as a lifting transport model, sand-dust aerosols and radiation parameterization scheme.Using this model, the super sand-dust storm case on 5 May was simulated. Results indicated that the coupled mesoscale model successfully simulated the mesoscale vortex, its strong upward movement and the warm core structure of PBL. The generation and development of these structures were consistent with that of the sand-dust storm and dry squall-line (which was different with normal squall-line). Simulated sand-dust concentration and its radiative effect corresponded with observation data. The radiative effect of sand-dust aerosols caused the air to heat on the top of aerosol layer with a heating rate amounting to 2 K hr -1 . As a result, solar radiation flux that reached the surface, net radiation flux and surface temperature all suddenly went down. The temperature gradient across the cold front became obviously larger. Therefore, enhancing the development of the mesoscale system. The simulation generally reflected features during the squall-line passage of this strong sand-dust storm

The time interval distribution of sand–dust storms in theory: testing with observational data for Yanchi, China

International Nuclear Information System (INIS)

Liu, Guoliang; Zhang, Feng; Hao, Lizhen

2012-01-01

We previously introduced a time record model for use in studying the duration of sand–dust storms. In the model, X is the normalized wind speed and Xr is the normalized wind speed threshold for the sand–dust storm. X is represented by a random signal with a normal Gaussian distribution. The storms occur when X ≥ Xr. From this model, the time interval distribution of N = Aexp(−bt) can be deduced, wherein N is the number of time intervals with length greater than t, A and b are constants, and b is related to Xr. In this study, sand–dust storm data recorded in spring at the Yanchi meteorological station in China were analysed to verify whether the time interval distribution of the sand–dust storms agrees with the above time interval distribution. We found that the distribution of the time interval between successive sand–dust storms in April agrees well with the above exponential equation. However, the interval distribution for the sand–dust storm data for the entire spring period displayed a better fit to the Weibull equation and depended on the variation of the sand–dust storm threshold wind speed. (paper)

Dust, Climate, and Human Health

Science.gov (United States)

Maynard, Nancy G.

2003-01-01

Air pollution from both natural and anthropogenic causes is considered to be one of the most serious world-wide environment-related health problems, and is expected to become worse with changes in the global climate. Dust storms from the atmospheric transport of desert soil dust that has been lifted and carried by the winds - often over significant distances - have become an increasingly important emerging air quality issue for many populations. Recent studies have shown that the dust storms can cause significant health impacts from the dust itself as well as the accompanying pollutants, pesticides, metals, salt, plant debris, and other inorganic and organic materials, including viable microorganisms (bacteria, viruses and fungi). For example, thousands of tons of Asian desert sediments, some containing pesticides and herbicides from farming regions, are commonly transported into the Arctic during dust storm events. These chemicals have been identified in animal and human tissues among Arctic indigenous populations. Millions of tons of airborne desert dust are being tracked by satellite imagery, which clearly shows the magnitude as well as the temporal and spatial variability of dust storms across the "dust belt" regions of North Africa, the Middle East, and China. This paper summarizes the most recent findings on the effects of airborne desert dust on human health as well as potential climate influences on dust and health.

Effects of dust storm events on weekly clinic visits related to pulmonary tuberculosis disease in Minqin, China

Science.gov (United States)

Wang, Yun; Wang, Ruoyu; Ming, Jing; Liu, Guangxiu; Chen, Tuo; Liu, Xinfeng; Liu, Haixia; Zhen, Yunhe; Cheng, Guodong

2016-02-01

Pulmonary tuberculosis (PTB) is a major public health problem in China. Minqin, a Northwest county of China, has a very high number of annual PTB clinic visits and it is also known for its severe dust storms. The epidemic usually begins in February and ends in July, while the dust storms mainly occur throughout spring and early summer, thereby suggesting that there might be a close link between the causative agent of PTB and dust storms. We investigated the general impact of dust storms on PTB over time by analyzing the variation in weekly clinic visits in Minqin during 2005-2012. We used the Mann-Whitney-Pettitt test and a regression model to determine the seasonal periodicity of PTB and dust storms in a time series, as well as assessing the relationships between meteorological variables and weekly PTB clinic visits. After comparing the number of weekly PTB cases in Gansu province with dust storm events, we detected a clear link between the population dynamics of PTB and climate events, i.e., the onset of epidemics and dust storms (defined by an atmospheric index) occurred in almost the same mean week. Thus, particulate matter might be the cause of PTB outbreaks on dust storm days. It is highly likely that the significant decline in annual clinic visits was closely associated with improvements in the local environment, which prevented desertification and decreased the frequency of dust storm events. To the best of our knowledge, this is the first population-based study to provide clear evidence that a PTB epidemic was affected by dust storms in China, which may give insights into the association between this environmental problem and the evolution of epidemic disease.

An analysis of the correlation between dust storms in Korea and 137Cs nuclide concentration

International Nuclear Information System (INIS)

Choi, Soo-won; Kim, Jeong-hun; Shin, Sang-hwa; Hwang, Joo-ho

2008-01-01

Dust storms occur in Korea during spring time when fine dust is blown in from the far western regions of western China and Mongolia. A fine powdery dust is blown up into the sky and enters the upper reaches of the atmosphere where it is carried easterly across China then slowly falls to the ground on the Korean peninsula and Japan. The dust originates mostly in the Gobi dessert of China, as well as the yellow earth regions in the middle and upper streams of the Yellow river in China. Previous studies on dust storms have been limited to following or estimating their courses, distribution and frequency, or distribution of the heavy metals they transmit. However, since radionuclides exist in the dust, they must also exist in the dust storms. In this study, we analyzed the correlation of :1 37 Cs nuclide concentration based on a count of annual dust storm occurrence in the city of Suwon, South Korea and assessed seasonal differences of 137 Cs nuclide concentration

Climate change implications and use of early warning systems for global dust storms

Science.gov (United States)

Harriman, Lindsey M.

2014-01-01

With increased changes in land cover and global climate, early detection and warning of dust storms in conjunction with effective and widespread information broadcasts will be essential to the prevention and mitigation of future risks and impacts. Human activities, seasonal variations and long-term climatic patterns influence dust storms. More research is needed to analyse these factors of dust mobilisation to create more certainty for the fate of vulnerable populations and ecosystems in the future. Early warning and communication systems, when in place and effectively implemented, can offer some relief to these vulnerable areas. As an issue that affects many regions of the world, there is a profound need to understand the potential changes and ultimately create better early warning systems for dust storms.

Numerical study of Asian dust transport during the springtime of 2001 simulated with the Chemical Weather Forecasting System (CFORS) model

Science.gov (United States)

Uno, Itsushi; Satake, Shinsuke; Carmichael, Gregory R.; Tang, Youhua; Wang, Zifa; Takemura, Toshihiko; Sugimoto, Nobuo; Shimizu, Atsushi; Murayama, Toshiyuki; Cahill, Thomas A.; Cliff, Steven; Uematsu, Mitsuo; Ohta, Sachio; Quinn, Patricia K.; Bates, Timothy S.

2004-10-01

The regional-scale aerosol transport model Chemical Weather Forecasting System (CFORS) is used for analysis of large-scale dust phenomena during the Asian Pacific Regional Characterization Experiment (ACE-Asia) intensive observation. Dust modeling results are examined with the surface weather reports, satellite-derived dust index (Total Ozone Mapping Spectrometer (TOMS) Aerosol Index (AI)), Mie-scattering lidar observation, and surface aerosol observations. The CFORS dust results are shown to accurately reproduce many of the important observed features. Model analysis shows that the simulated dust vertical loading correlates well with TOMS AI and that the dust loading is transported with the meandering of the synoptic-scale temperature field at the 500-hPa level. Quantitative examination of aerosol optical depth shows that model predictions are within 20% difference of the lidar observations for the major dust episodes. The structure of the ACE-Asia Perfect Dust Storm, which occurred in early April, is clarified with the help of the CFORS model analysis. This storm consisted of two boundary layer components and one elevated dust (>6-km height) feature (resulting from the movement of two large low-pressure systems). Time variation of the CFORS dust fields shows the correct onset timing of the elevated dust for each observation site, but the model results tend to overpredict dust concentrations at lower latitude sites. The horizontal transport flux at 130°E longitude is examined, and the overall dust transport flux at 130°E during March-April is evaluated to be 55 Tg.

Investigation of dust storms entering Western Iran using remotely sensed data and synoptic analysis.

Science.gov (United States)

Boloorani, Ali D; Nabavi, Seyed O; Bahrami, Hosain A; Mirzapour, Fardin; Kavosi, Musa; Abasi, Esmail; Azizi, Rasoul

2014-01-01

One of the natural phenomena which have had considerable impacts on various regions of the world, including Iran, is "dust storm". In recent years, this phenomenon has taken on new dimensions in Iran and has changed from a local problem to a national issue. This study is an attempt to investigate the formation of the dust storms crossing the Western Iran. To find the sources of the dust storms entering Iran, first we examine three determined dust paths in the region and their temporal activities, using MODIS satellite images. Then, four regions were identified as dust sources through soil, land cover and wind data. Finally, atmospheric analyses are implemented to find synoptic patterns inducing dust storms. Source 1 has covered the region between the eastern banks of Euphrates and western banks of Tigris. Source 2 is in desert area of western and south-western Iraq. Finally source 3 is bounded in eastern and south-eastern deserts of Saudi Arabia called Rub-Al-Khali desert, or Empty Quarter. Moreover, south-eastern part of Iraq (source 4) was also determined as a secondary source which thickens the dust masses originating from the above mentioned sources. The study of synoptic circulations suggests that the dust storms originating from source 1 are formed due to the intense pressure gradient between the low-pressure system of Zagros and a high-pressure cell formed on Mediterranean Sea. The dust events in sources 2 and 3 are outcomes of the atmospheric circulations dominant in the cold period of the year in mid-latitudes.

Parameterization of Rocket Dust Storms on Mars in the LMD Martian GCM: Modeling Details and Validation

Science.gov (United States)

Wang, Chao; Forget, François; Bertrand, Tanguy; Spiga, Aymeric; Millour, Ehouarn; Navarro, Thomas

2018-04-01

The origin of the detached dust layers observed by the Mars Climate Sounder aboard the Mars Reconnaissance Orbiter is still debated. Spiga et al. (2013, https://doi.org/10.1002/jgre.20046) revealed that deep mesoscale convective "rocket dust storms" are likely to play an important role in forming these dust layers. To investigate how the detached dust layers are generated by this mesoscale phenomenon and subsequently evolve at larger scales, a parameterization of rocket dust storms to represent the mesoscale dust convection is designed and included into the Laboratoire de Météorologie Dynamique (LMD) Martian Global Climate Model (GCM). The new parameterization allows dust particles in the GCM to be transported to higher altitudes than in traditional GCMs. Combined with the horizontal transport by large-scale winds, the dust particles spread out and form detached dust layers. During the Martian dusty seasons, the LMD GCM with the new parameterization is able to form detached dust layers. The formation, evolution, and decay of the simulated dust layers are largely in agreement with the Mars Climate Sounder observations. This suggests that mesoscale rocket dust storms are among the key factors to explain the observed detached dust layers on Mars. However, the detached dust layers remain absent in the GCM during the clear seasons, even with the new parameterization. This implies that other relevant atmospheric processes, operating when no dust storms are occurring, are needed to explain the Martian detached dust layers. More observations of local dust storms could improve the ad hoc aspects of this parameterization, such as the trigger and timing of dust injection.

The relationship between gorgonian coral (Cnidaria: Gorgonacea) diseases and African dust storms

Science.gov (United States)

Weir-Brush, J. R.; Garrison, V.H.; Smith, G.W.; Shinn, E.A.

2004-01-01

The number of reports of coral diseases has increased throughout the world in the last 20 years. Aspergillosis, which primarily affects Gorgonia ventalina and G. flabellum, is one of the few diseases to be characterized. This disease is caused by Aspergillus sydowii, a terrestrial fungus with a worldwide distribution. Upon infection, colonies may lose tissue, and ultimately, mortality may occur if the infection is not sequestered. The spores of A. sydowii are African dust storms transport and deposit pathogens, we collected air samples from both dust storms and periods of nondust in St. John, U.S. Virgin Islands. Because we focused on fungal pathogens and used A. sydowii as a model, we isolated and cultured fungi on various types of media. Fungi including Aspergillus spp. were isolated from air samples taken from dust events and non-dust events. Twenty-three separate cultures and seven genera were isolated from dust event samples whereas eight cultures from five genera were isolated from non-dust air samples. Three isolates from the Virgin Islands dust event samples morphologically identified as Aspergillus spp. produced signs of aspergillosis in seafans, and the original pathogens were re-isolated from those diseased seafans fulfilling Koch's Postulates. This research supports the hypothesis that African dust storms transport across the Atlantic Ocean and deposit potential coral pathogens in the Caribbean.

Aerosol Particles from Dried Salt-Lakes and Saline Soils Carried on Dust Storms over Beijing

Directory of Open Access Journals (Sweden)

Xingying Zhang

2009-01-01

Full Text Available Characteristics of individual particles from a super dust storm (DS on 20 March 2002, and those of non dust storm aero sols for Beijing (NDS and Duolun (DL (a desert area are determined using a variety of methods. In China, typically the source of aero sols in dust storms is thought to be deserts with alumino silicates being the main constituent particles; how ever, this does not reflect a complete analysis with our evidence indicating potential alternate dust sources along the storm's trans port path. Individual particle anal y sis of aero sols collected from a super dust storm on 20 March 2002 in Beijing shows that among all the 14 elements measured, only S and Cl have re mark able positive correlation. 82.5% of all particles measured contained both S and Cl, and the relative mass per cent age of S and Cl in these particles is much higher than the average of all particles. 62.0% of all particles contained S, Cl, and Na, in which the concentration of Na is 1.4 times higher than average. PMF (Positive Matrix Factorization anal y sis indicates that NaCl and Na2SO4 are major components of these particles with S and Cl showing significant positive correlation. More over, SO4 2- and Cl- also show significant positive correlation in bulk aero sol analysis. XPS (X-ray Pho to electron Spectros copy analysis of the surface of aero sols demonstrates that concentrations of Na and S on particles from the dust storm are higher than those from non-dust storm particles in Beijing and also for particles from. It is very likely that particles enriched with S, Cl, and Na is from the surface soils of dried salt-lakes and saline soils enriched with chloride and sulfate. This evidence demonstrates that be sides deserts, surface soils from dry salt-lakes and saline soils of arid and semi-arid areas are also sources of particulates in dust storms over Beijing.

Metagenomic Analysis of Airborne Bacterial Community and Diversity in Seoul, Korea, during December 2014, Asian Dust Event.

Science.gov (United States)

Cha, Seho; Srinivasan, Sathiyaraj; Jang, Jun Hyeong; Lee, Dongwook; Lim, Sora; Kim, Kyung Sang; Jheong, Weonhwa; Lee, Dong-Won; Park, Eung-Roh; Chung, Hyun-Mi; Choe, Joonho; Kim, Myung Kyum; Seo, Taegun

2017-01-01

Asian dust or yellow sand events in East Asia are a major issue of environmental contamination and human health, causing increasing concern. A high amount of dust particles, especially called as particulate matter 10 (PM10), is transported by the wind from the arid and semi-arid tracks to the Korean peninsula, bringing a bacterial population that alters the terrestrial and atmospheric microbial communities. In this study, we aimed to explore the bacterial populations of Asian dust samples collected during November-December 2014. The dust samples were collected using the impinger method, and the hypervariable regions of the 16S rRNA gene were amplified using PCR followed by pyrosequencing. Analysis of the sequencing data were performed using Mothur software. The data showed that the number of operational taxonomic units and diversity index during Asian dust events were higher than those during non-Asian dust events. At the phylum level, the proportions of Proteobacteria, Actinobacteria, and Firmicutes were different between Asian dust and non-Asian dust samples. At the genus level, the proportions of the genus Bacillus (6.9%), Arthrobacter (3.6%), Blastocatella (2%), Planomicrobium (1.4%) were increased during Asian dust compared to those in non-Asian dust samples. This study showed that the significant relationship between bacterial populations of Asian dust samples and non-Asian dust samples in Korea, which could significantly affect the microbial population in the environment.

Desert Dust and Health: A Central Asian Review and Steppe Case Study

Directory of Open Access Journals (Sweden)

Troy Sternberg

2017-11-01

Full Text Available In Asian deserts environmental and anthropomorphic dust is a significant health risk to rural populations. Natural sources in dry landscapes are exacerbated by human activities that increase the vulnerability to dust and dust-borne disease vectors. Today in Central and Inner Asian drylands, agriculture, mining, and rapid development contribute to dust generation and community exposure. Thorough review of limited dust investigation in the region implies but does not quantify health risks. Anthropogenic sources, such as the drying of the Aral Sea, highlight the shifting dust dynamics across the Central EurAsian steppe. In the Gobi Desert, our case study in Khanbogd, Mongolia addressed large-scale mining’s potential dust risk to the health of the local population. Dust traps showed variable exposure to particulates among herder households and town residents; dust density distribution indicated that sources beyond the mine need to be considered when identifying particulate sources. Research suggests that atmospheric dust from multiple causes may enhance human particulate exposure. Greater awareness of dust in greater Central Asia reflects community concern about related health implications. Future human well-being in the region will require more thorough information on dust emissions in the changing environment.

Desert Dust and Health: A Central Asian Review and Steppe Case Study.

Science.gov (United States)

Sternberg, Troy; Edwards, Mona

2017-11-03

In Asian deserts environmental and anthropomorphic dust is a significant health risk to rural populations. Natural sources in dry landscapes are exacerbated by human activities that increase the vulnerability to dust and dust-borne disease vectors. Today in Central and Inner Asian drylands, agriculture, mining, and rapid development contribute to dust generation and community exposure. Thorough review of limited dust investigation in the region implies but does not quantify health risks. Anthropogenic sources, such as the drying of the Aral Sea, highlight the shifting dust dynamics across the Central EurAsian steppe. In the Gobi Desert, our case study in Khanbogd, Mongolia addressed large-scale mining's potential dust risk to the health of the local population. Dust traps showed variable exposure to particulates among herder households and town residents; dust density distribution indicated that sources beyond the mine need to be considered when identifying particulate sources. Research suggests that atmospheric dust from multiple causes may enhance human particulate exposure. Greater awareness of dust in greater Central Asia reflects community concern about related health implications. Future human well-being in the region will require more thorough information on dust emissions in the changing environment.

Thermal Tides During the 2001 Martian Global-Scale Dust Storm

Science.gov (United States)

Guzewich, Scott D.; Wilson, R. John; McConnochie, Timothy H.; Toigo, Anthony D.; Bandfield, Donald J.; Smith, Michael D.

2014-01-01

The 2001 (Mars Year 25) global dust storm radically altered the dynamics of the Martian atmosphere. Using observations from the Thermal Emission Spectrometer onboard the Mars Global Surveyor spacecraft and Mars WRF general circulation model simulations, we examine the changes to thermal tides and planetary waves caused by the storm. We find that the extratropical diurnal migrating tide is dramatically enhanced during the storm, particularly in the southern hemisphere, reaching amplitudes of more than 20 K. The tropical diurnal migrating tide is weakened to almost undetectable levels. The diurnal Kelvin waves are also significantly weakened, particularly during the period of global expansion at Ls=200deg-210deg. In contrast, the westward propagating diurnal wavenumber 2 tide strengthens to 4-8 K at altitudes above 30km. The wavenumber 1 stationary wave reaches amplitudes of 10-12 K at 50deg-70degN, far larger than is typically seen during this time of year. The phase of this stationary wave and the enhancement of the diurnal wavenumber 2 tide appear to be responses to the high-altitude westward propagating equatorial wavenumber 1 structure in dust mixing ratio observed during the storm in previous works. This work provides a global picture of dust storm wave dynamics that reveals the coupling between the tropics and high-latitude wave responses. We conclude that the zonal distribution of thermotidal forcing from atmospheric aerosol concentration is as important to understanding the atmospheric wave response as the total global mean aerosol optical depth.

Vulnerability Assessment of Dust Storms in the United States under a Changing Climate Scenario

Science.gov (United States)

Severe weather events, such as flooding, drought, forest fires, and dust storms can have a serious impact on human health. Dust storm events are not well predicted in the United States, however they are expected to become more frequent as global climate warms through the 21st cen...

An Extensive Study on Dynamical aspects of Dust Storm over the United Arab Emirates during 18-20 March 2012

Science.gov (United States)

Basha, Ghouse; Phanikumar, Devulapalli V.; Ouarda, Taha B. M. J.

2015-04-01

On 18 March 2012, a super dust storm event occurred over Middle East (ME) and lasted for several hours. Following to this, another dust storm occurred on early morning of 20 March 2012 with almost higher intensity. Both these storms reduced the horizontal visibility to few hundreds of meters and represented as one of the most intense and long duration dust storms over United Arab Emirates (UAE) in recent times. These storms also reduced the air quality in most parts of the ME implying the shutdown of Airports, schools and hundreds of people were hospitalized with respirational problems. In the context of the above, we have made a detailed study on the dynamical processes leading to triggering of dust storm over UAE and neighboring regions. We have also analyzed its impact on surface, and vertical profiles of background parameters and aerosols during the dust storm period by using ground-based, space borne, dust forecasting model, and reanalysis data sets. The synoptic and dynamic conditions responsible for the occurrence of the dust storm are discussed extensively by using European Centre for Medium-Range Weather Forecasts (ECMWF) ERA interim reanalysis data sets. The Impact of dust storm on surface and upper air radiosonde measurements and aerosol optical properties are also investigated before, during and after the dust storm event. During the dust storm, surface temperature decreased by 15oC when compared to before and after the event. PM10 values significantly increased maximum of about 1600µg/m3. Spatial variation of Aerosol Optical Depth (AOD) from Moderate-resolution Imaging Spectroradiometer (MODIS) and Ozone Monitoring Instrument (OMI) aerosol index (AI) exhibited very high values during the event and source region can be identified of dust transport to our region with this figure. The total attenuated backscatter at 550nm from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite shows the vertical extent of dust up to 8km. The dynamics of this event is

The dual effect of vegetation green-up date and strong wind on the return period of spring dust storms.

Science.gov (United States)

Feng, Jieling; Li, Ning; Zhang, Zhengtao; Chen, Xi

2017-08-15

Vegetation phenology changes have been widely applied in the disaster risk assessments of the spring dust storms, and vegetation green-up date shifts have a strong influence on dust storms. However, the effect of earlier vegetation green-up dates due to climate warming on the evaluation of dust storms return periods remains an important, but poorly understood issue. In this study, we evaluate the spring dust storm return period (February to June) in Inner Mongolia, Northern China, using 165 observations of severe spring dust storm events from 16 weather stations, and regional vegetation green-up dates as an integrated factor from NDVI (Normalized Difference Vegetation Index), covering a period from 1982 to 2007, by building the bivariate Copula model. We found that the joint return period showed better fitting results than without considering the integrated factor when the actual dust storm return period is longer than 2years. Also, for extremely severe dust storm events, the gap between simulation result and actual return period can be narrowed up to 0.4888years by using integrated factor. Furthermore, the risk map based on the return period results shows that the Mandula, Zhurihe, Sunitezuoqi, Narenbaolige stations are identified as high risk areas. In this study area, land surface is extensively covered by grasses and shrubs, vegetation green-up date can play a significant role in restraining spring dust storm outbreaks. Therefore, we suggest that Copula method can become a useful tool for joint return period evaluation and risk analysis of severe dust storms. Copyright © 2017 Elsevier B.V. All rights reserved.

Quantitative detection of mass concentration of sand-dust storms via wind-profiling radar and analysis of Z- M relationship

Science.gov (United States)

Wang, Minzhong; Ming, Hu; Ruan, Zheng; Gao, Lianhui; Yang, Di

2018-02-01

With the aim to achieve quantitative monitoring of sand-dust storms in real time, wind-profiling radar is applied to monitor and study the process of four sand-dust storms in the Tazhong area of the Taklimakan Desert. Through evaluation and analysis of the spatial-temporal distribution of reflectivity factor, it is found that reflectivity factor ranges from 2 to 18 dBz under sand-dust storm weather. Using echo power spectrum of radar vertical beams, sand-dust particle spectrum and sand-dust mass concentration at the altitude of 600 ˜ 1500 m are retrieved. This study shows that sand-dust mass concentration reaches 700 μg/m3 under blowing sand weather, 2000 μg/m3 under sand-dust storm weather, and 400 μg/m3 under floating dust weather. The following equations are established to represent the relationship between the reflectivity factor and sand-dust mass concentration: Z = 20713.5 M 0.995 under floating dust weather, Z = 22988.3 M 1.006 under blowing sand weather, and Z = 24584.2 M 1.013 under sand-dust storm weather. The retrieval results from this paper are almost consistent with previous monitoring results achieved by former researchers; thus, it is implied that wind-profiling radar can be used as a new reference device to quantitatively monitor sand-dust storms.

The cascade from local to global dust storms on Mars: Temporal and spatial thresholds on thermal and dynamical feedback

Science.gov (United States)

Toigo, Anthony D.; Richardson, Mark I.; Wang, Huiqun; Guzewich, Scott D.; Newman, Claire E.

2018-03-01

We use the MarsWRF general circulation model to examine the temporal and spatial response of the atmosphere to idealized local and regional dust storm radiative heating. The ability of storms to modify the atmosphere away from the location of dust heating is a likely prerequisite for dynamical feedbacks that aid the growth of storms beyond the local scale, while the ability of storms to modify the atmosphere after the cessation of dust radiative heating is potentially important in preconditioning the atmosphere prior to large scale storms. Experiments were conducted over a range of static, prescribed storm sizes, durations, optical depth strengths, locations, and vertical extents of dust heating. Our results show that for typical sizes (order 105 km2) and durations (1-10 sols) of local dust storms, modification of the atmosphere is less than the typical variability of the unperturbed (storm-free) state. Even if imposed on regional storm length scales (order 106 km2), a 1-sol duration storm similarly does not significantly modify the background atmosphere. Only when imposed for 10 sols does a regional dust storm create a significant impact on the background atmosphere, allowing for the possibility of self-induced dynamical storm growth. These results suggest a prototype for how the subjective observational categorization of storms may be related to objective dynamical growth feedbacks that only become available to storms after they achieve a threshold size and duration, or if they grow into an atmosphere preconditioned by a prior large and sustained storm.

Operational aerosol and dust storm forecasting

International Nuclear Information System (INIS)

Westphal, D L; Curtis, C A; Liu, M; Walker, A L

2009-01-01

The U. S. Navy now conducts operational forecasting of aerosols and dust storms on global and regional scales. The Navy Aerosol Analysis and Prediction System (NAAPS) is run four times per day and produces 6-day forecasts of sulfate, smoke, dust and sea salt aerosol concentrations and visibility for the entire globe. The Coupled Ocean Atmosphere Mesoscale Prediction System (COAMPS (registered) ) is run twice daily for Southwest Asia and produces 3-day forecasts of dust, smoke, and visibility. The graphical output from these models is available on the Internet (www.nrlmry.navy.mil/aerosol/). The aerosol optical properties are calculated for each specie for each forecast output time and used for sea surface temperature (SST) retrieval corrections, regional electro-optical (EO) propagation assessments, and the development of satellite algorithms. NAAPS daily aerosol optical depth (AOD) values are compared with the Advanced Very High Resolution Radiometer (AVHRR) and Moderate Resolution Imaging Spectroradiometer (MODIS) AOD values. Visibility forecasts are compared quantitatively with surface synoptic reports.

Simulation of spontaneous and variable global dust storms with the GFDL Mars GCM

OpenAIRE

Basu, Shabari; Wilson, John; Richardson, Mark; Ingersoll, Andrew

2006-01-01

We report on the successful simulation of global dust storms in a general circulation model. The simulated storms develop spontaneously in multiyear simulations and exhibit significant interannual variability. The simulated storms produce dramatic increases in atmospheric dustiness, global-mean air temperatures, and atmospheric circulation intensity, in accord with observations. As with observed global storms, spontaneous initiation of storms in the model occurs in southern spring and summer,...

[Dust storms trend in the Capital Circle of China over the past 50 years and its correlation with temperature, precipitation and wind].

Science.gov (United States)

Chen, Yu-fu; Tang, Hai-ping

2005-01-01

The trends of number of dust storm days of the selected 11 meteorological stations from their established year to 2000 as well as their correlations with temperature, precipitation and wind are revealed. The number of dust storm days of the Capital Circle of China is distinctly variable in space and time. The numbers of dust storm days of the western area are far more than those of the eastern area. The interannual variability of number of dust storm days is remarkable. The number of dust storm days of the following 7 stations, Erlianhaote, Abaga, Xilinhaote, Fengning, Zhangjiakou, Huailai and Beijing, declined along the past decades, but those of the other four stations had no significant upward or downward trends. There is a marked seasonality of the number of dust storm days, and the maximum was in April. The correlation between number of dust storm days and number of days of mean wind velocity > 5 m/s, which is critical wind velocity to entrain sand into the air, was strongest among the three climatic factor. There were significant positive correlations between the number of dust storm days and number of days of mean wind velocity > 5 m/s in 6 stations. The second strongest climatic factor correlated with the number of dust storm days is temperature. There are significant negative correlations between the number of dust storm days and mean annual temperature, mean winter temperature, mean spring temperature in 3 or 4 stations. The correlation between the number of dust storm days and precipitation is weakest. Only one station, Zhurihe, showes significant negative correlation between the number of dust storm days and spring rainfall. There are 4 stations whose number of dust storm days don't significantly correlate with the climate. In the end, the spatial-temporal variability of dust storms and its relation with climate in the Capital Circle of China were discussed thoroughly.

Impacts of sand and dust storms on agriculture and potential agricultural applications of a SDSWS

International Nuclear Information System (INIS)

Stefanski, R; Sivakumar, M V K

2009-01-01

This paper will give an overview of the various impacts of sand and dust storms on agriculture and then address the potential applications of a Sand and Dust Storm Warning System (SDSWS) for agricultural users. Sand and dust storms have many negative impacts on the agricultural sector including: reducing crop yields by burial of seedlings under sand deposits, the loss of plant tissue and reduced photosynthetic activity as a result of sandblasting, delaying plant development, increasing end-of-season drought risk, causing injury and reduced productivity of livestock, increasing soil erosion and accelerating the process of land degradation and desertification, filling up irrigation canals with sediments, covering transportation routes, affecting water quality of rivers and streams, and affecting air quality. One positive impact is the fertilization of soil minerals to terrestrial ecosystems. There are several potential agricultural applications of a SDSWS. The first is to alert agricultural communities farmers to take preventive action in the near-term such as harvesting maturing crops (vegetables, grain), sheltering livestock, and strengthening infrastructure (houses, roads, grain storage) for the storm. Also, the products of a SDSWS could be used in for monitoring potential locust movement and post-storm crop damage assessments. An archive of SDSWS products (movement, amount of sand and dust) could be used in researching plant and animal pathogen movement and the relationship of sand and dust storms to disease outbreaks and in developing improved soil erosion and land degradation models.

Change of the Asian dust source region deduced from the composition of anthropogenic radionuclides in surface soil in Mongolia

Directory of Open Access Journals (Sweden)

Y. Igarashi

2011-07-01

Full Text Available Recent climate change, especially during the 2000s, may be the primary reason for the expansion of the Asian dust source region. The change in the dust source region was investigated by examining anthropogenic radionuclides contained in surface soil samples from Mongolia. Surface soil was globally labeled by radioactive fallout from nuclear testing during the late 1950s and early 1960s, but there are no current direct sources for anthropogenic radionuclides in the air (before the Fukushima nuclear power plant accident in 2011. Radionuclides in the atmosphere are therefore carried mainly by wind-blown dust from surface soil, that is, aeolian dust. Asian dust carries traces of ⁹⁰Sr, ¹³⁷Cs, and other anthropogenic radionuclides; the heaviest deposition occurs in spring and has been recorded in Japan since the early 1990s. The composition of anthropogenic radionuclides in atmospheric depositions would be affected by a change in the dust source. Previous studies of atmospheric deposition at long-term monitoring sites (e.g. in Tsukuba, Japan have detected changes in the ¹³⁷Cs/⁹⁰Sr ratio and in the specific activity of the radionuclides. These changes in the composition of observed atmospheric depositions are supposed to reflect changes in the climatic conditions of the dust source region. To investigate this dust source change, we conducted a field survey of radionuclides (⁹⁰Sr and ¹³⁷Cs in surface soil samples in September 2007 in the eastern and southern regions of Mongolia, where dust storms have occurred more frequently since 2000. The specific activities of both radionuclides as well as the ¹³⁷Cs/⁹⁰Sr ratio in the surface soil were well correlated with annual average precipitation in the Mongolian desert-steppe zone. Higher specific activities and a higher ¹³⁷Cs/⁹⁰Sr ratio were found in grassland regions that experienced greater

Hydrogen escape from Mars enhanced by deep convection in dust storms

Science.gov (United States)

Heavens, Nicholas G.; Kleinböhl, Armin; Chaffin, Michael S.; Halekas, Jasper S.; Kass, David M.; Hayne, Paul O.; McCleese, Daniel J.; Piqueux, Sylvain; Shirley, James H.; Schofield, John T.

2018-02-01

Present-day water loss from Mars provides insight into Mars's past habitability1-3. Its main mechanism is thought to be Jeans escape of a steady hydrogen reservoir sourced from odd-oxygen reactions with near-surface water vapour2, 4,5. The observed escape rate, however, is strongly variable and correlates poorly with solar extreme-ultraviolet radiation flux6-8, which was predicted to modulate escape9. This variability has recently been attributed to hydrogen sourced from photolysed middle atmospheric water vapour10, whose vertical and seasonal distribution is only partly characterized and understood11-13. Here, we report multi-annual observational estimates of water content and dust and water transport to the middle atmosphere from Mars Climate Sounder data. We provide strong evidence that the transport of water vapour and ice to the middle atmosphere by deep convection in Martian dust storms can enhance hydrogen escape. Planet-encircling dust storms can raise the effective hygropause (where water content rapidly decreases to effectively zero) from 50 to 80 km above the areoid (the reference equipotential surface). Smaller dust storms contribute to an annual mode in water content at 40-50 km that may explain seasonal variability in escape. Our results imply that Martian atmospheric chemistry and evolution can be strongly affected by the meteorology of the lower and middle atmosphere of Mars.

Spectral Signature of Radiative Forcing by East Asian Dust-Soot Mixture

Science.gov (United States)

Zhu, A.; Ramanathan, V.

2007-12-01

The Pacific Dust Experiment (PACDEX) provides the first detailed sampling of dust-soot mixtures from the western Pacific to the eastern Pacific Ocean. The data includes down and up spectral irradiance, mixing state of dust and soot, and other aerosol properties. This study attempts to simulate the radiative forcing by dust-soot mixtures during the experimental period. The MODTRAN band model was employed to investigate the spectral signatures of solar irradiance change induced by aerosols at moderate spectral resolutions. For the short wave band (300-1100nm) used in this study, the reduction of downward irradiance at surface by aerosols greatly enhances with increasing wavelength in the UV band (300-400nm), reaches a maximum in the blue band, then gradually decreases toward the red band. In the near-IR band (700-1100nm), irradiance reduction by aerosols shows great fluctuations in the band with center wavelength at around 940nm, 820nm, 720nm, 760nm, 690nm, where the aerosol effect is overwhelmed by the water vapor and O2 absorptions. The spectral pattern of irradiance reduction varies for different aerosol species. The maximum reduction lies at around 450nm for soot, and shifting to about 490nm for East Asian mineral dust. It's worth noting that although soot aerosols reduce more irradiance than East Asian dust in the UV and blue band, the impact of dust to the irradiance exceeds that by soot at the longer wavelength band (i.e. around 550nm). The reduction of irradiance by East Asian dust (soot) in the UV band, visible band, and near-IR accounts for about 6% (10%), 56% (64%), and 38% (26%) of total irradiance reduction. As large amount of soot aerosols are involved during the long range transport of East Asian dust, the optical properties of dust aerosols are modified with different mixing state with soot, the spectral pattern of the irradiance reduction will be changed. The study of aerosol forcing at moderate spectral resolutions has the potential application for

Difference in Pro-Inflammatory Cytokine Responses Induced in THP1 Cells by Particulate Matter Collected on Days with and without ASIAN Dust Storms

Directory of Open Access Journals (Sweden)

Masanari Watanabe

2015-07-01

Full Text Available The associations between particulate matter from Asian dust storms (ADS and health disorders differ among studies, and the underlying mechanisms remain unclear. In this study, ADS and non-ADS particles were tested for their potential to induce pro-inflammatory cytokines associated with adverse respiratory effects. Particulate matter was collected in Japan during four periods in 2013 (2 × ADS periods; 2 × non-ADS. THP1 cells were exposed to this particulate matter, and the levels of various interleukins (ILs, and tumor necrosis factor (TNF-α were measured. Levels of IL-2 increased significantly following exposure to all particulate matter samples (compared to levels in a solvent control. Increased levels of IL-10 and TNF-α were also observed following exposure to particles collected during three (one ADS and two non-ADS and two (one ADS and one non-ADS collection periods, respectively. Thus, the effects of particulate matter on cytokine responses differed according to collection period, and the effects of ADS particles differed for each ADS event. Additionally, the levels of pro-inflammatory cytokines induced by ADS particles were not always higher than those induced by non-ADS particles.

Observation of Asian dust properties by using multi-wavelength LIDAR system at anmyeon island, Korea

International Nuclear Information System (INIS)

Choi, Sung Chul; Ko, Do Kyeoung; Lee, Jong Min; Kim, Young Joon; Noh, Young Min

2004-01-01

The Asian dust affect climate both directly and indirectly because they act as effective ice nuclei and forms ice cloud. However, little is known about spatial distribution and trajectory because few measurement data are available in the free troposphere over East Asia, where a large amount of Asian dust are transported form desert regions in Asian continent. LIDAR system is an effective tool for remotely measuring the vertical distribution of aerosol optical properties. For measurement of Asian dust optical properties, a multi-wavelength LIDAR system developed by the Advanced Environment Monitoring Research Center (ADEMRC), Gwangju Institute Science and Technology (GIST), Korea. This paper presents the results of ground-based multi-wavelength LIDAR measurements of the Asian dust aerosol over Anmyeon Island (36.40N, 126.10E) during the spring of 2004. To discriminate between Asian dust and cloud, depolarization ratio is useful for the detection of these particles and the LIDAR ratio. Also, we discuss the relationship between LIDAR ratio and other optical properties from LIDAR measurement, i.e., the depolarization ratio, aerosol extinction coefficient and LIDAR ratio

Long-Term Observations of Dust Storms in Sandy Desert Environments

Science.gov (United States)

Yun, Hye-Won; Kim, Jung-Rack; Choi, Yun-Soo

2015-04-01

Mineral dust occupies the largest portion of atmospheric aerosol. Considering the numerous risks that dust poses for socioeconomic and anthropogenic activities, it is crucial to understand sandy desert environments, which frequently generate dust storms and act as a primary source of atmospheric aerosol. To identify mineral aerosol mechanisms, it is essential to monitor desert environmental factors involving dust storm generation in the long term. In this study, we focused on two major environmental factors: local surface roughness and soil moisture. Since installments of ground observation networks in sandy deserts are unfeasible, remote sensing techniques for mining desert environmental factors were employed. The test area was established within the Badain Jaran and Kubuqi Deserts in Inner Mongolia, China, where significant seasonal aeolian processes emit mineral dust that influences all of East Asia. To trace local surface roughness, we employed a multi-angle imaging spectroradiometer (MISR) image sequence to extract multi-angle viewing (MAV) topographic parameters such as normalized difference angular index, which represents characteristics of the target desert topography. The backscattering coefficient from various space-borne SAR and stereotopography were compared with MAV observations to determine calibrated local surface roughness. Soil moisture extraction techniques from InSAR-phase coherence stacks were developed and compiled with advanced scatterometer (ASCAT) soil moisture data. Combined with metrological information such as the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA interim, correlations between intensity of sand dune activity as a proxy of aeolian processes in desert environments, surface wind conditions, and surface soil moisture were traced. Overall, we have confirmed that tracking sandy desert aeolian environments for long-term observations is feasible with space-borne, multi-sensor observations when combined with

Limited production of sulfate and nitrate on front-associated dust storm particles moving from desert to distant populated areas in northwestern China

Science.gov (United States)

Wu, Feng; Zhang, Daizhou; Cao, Junji; Guo, Xiao; Xia, Yao; Zhang, Ting; Lu, Hui; Cheng, Yan

2017-12-01

Sulfate and nitrate compounds can greatly increase the hygroscopicity of mineral particles in the atmosphere and consequently alter the particles' physical and chemical properties. Their uptake on long-distance-transported Asian dust particles within mainland China has been reported to be substantial in previous studies, but the production was very inefficient in other studies. We compared these two salts in particles collected from a synoptic-scale, mid-latitude, cyclone-induced dust storm plume at the Tengger Desert (38.79° N, 105.38° E) and in particles collected in a postfrontal dust plume at an urban site in Xi'an (34.22° N, 108.87° E) when a front-associated dust storm from the Tengger Desert arrived there approximately 700 km downwind. The results showed that the sulfate concentration was not considerably different at the two sites, while the nitrate concentration was slightly larger at the urban site than that at the desert site. The estimated nitrate production rate was 4-5 ng µg-1 of mineral dust per day, which was much less than that in polluted urban air. The adiabatic process of the dust-loading air was suggested to be the reason for the absence of sulfate formation, and the uptake of background HNO3 was suggested to be the reason for the small nitrate production. According to our investigation of the published literature, the significant sulfate and nitrate in dust-storm-associated samples within the continental atmosphere reported in previous studies cannot be confirmed as actually produced on desert dust particles; the contribution from locally emitted and urban mineral particles or from soil-derived sulfate was likely substantial because the weather conditions in those studies indicated that the collection of the samples was started before dust arrival, or the air from which the samples were collected was a mixture of desert dust and locally emitted mineral particles. These results suggest that the production of nitrate and sulfate on dust

Limited production of sulfate and nitrate on front-associated dust storm particles moving from desert to distant populated areas in northwestern China

Directory of Open Access Journals (Sweden)

F. Wu

2017-12-01

Full Text Available Sulfate and nitrate compounds can greatly increase the hygroscopicity of mineral particles in the atmosphere and consequently alter the particles' physical and chemical properties. Their uptake on long-distance-transported Asian dust particles within mainland China has been reported to be substantial in previous studies, but the production was very inefficient in other studies. We compared these two salts in particles collected from a synoptic-scale, mid-latitude, cyclone-induced dust storm plume at the Tengger Desert (38.79° N, 105.38° E and in particles collected in a postfrontal dust plume at an urban site in Xi'an (34.22° N, 108.87° E when a front-associated dust storm from the Tengger Desert arrived there approximately 700 km downwind. The results showed that the sulfate concentration was not considerably different at the two sites, while the nitrate concentration was slightly larger at the urban site than that at the desert site. The estimated nitrate production rate was 4–5 ng µg−1 of mineral dust per day, which was much less than that in polluted urban air. The adiabatic process of the dust-loading air was suggested to be the reason for the absence of sulfate formation, and the uptake of background HNO3 was suggested to be the reason for the small nitrate production. According to our investigation of the published literature, the significant sulfate and nitrate in dust-storm-associated samples within the continental atmosphere reported in previous studies cannot be confirmed as actually produced on desert dust particles; the contribution from locally emitted and urban mineral particles or from soil-derived sulfate was likely substantial because the weather conditions in those studies indicated that the collection of the samples was started before dust arrival, or the air from which the samples were collected was a mixture of desert dust and locally emitted mineral particles. These results suggest that the

Impact of mineral dust on nitrate, sulfate, and ozone in transpacific Asian pollution plumes

Directory of Open Access Journals (Sweden)

T. D. Fairlie

2010-04-01

Full Text Available We use a 3-D global chemical transport model (GEOS-Chem to interpret aircraft observations of nitrate and sulfate partitioning in transpacific dust plumes during the INTEX-B campaign of April–May 2006. The model includes explicit transport of size-resolved mineral dust and its alkalinity, nitrate, and sulfate content. The observations show that particulate nitrate is primarily associated with dust, sulfate is primarily associated with ammonium, and Asian dust remains alkaline across the Pacific. This can be reproduced in the model by using a reactive uptake coefficient for HNO₃ on dust (γ(HNO₃ ~10⁻³ much lower than commonly assumed in models and possibly reflecting limitation of uptake by dust dissolution. The model overestimates gas-phase HNO₃ by a factor of 2–3, typical of previous model studies; we show that this cannot be corrected by uptake on dust. We find that the fraction of aerosol nitrate on dust in the model increases from ~30% in fresh Asian outflow to 80–90% over the Northeast Pacific, reflecting in part the volatilization of ammonium nitrate and the resulting transfer of nitrate to the dust. Consumption of dust alkalinity by uptake of acid gases in the model is slow relative to the lifetime of dust against deposition, so that dust does not acidify (at least not in the bulk. This limits the potential for dust iron released by acidification to become bio-available upon dust deposition. Observations in INTEX-B show no detectable ozone depletion in Asian dust plumes, consistent with the model. Uptake of HNO₃ by dust, suppressing its recycling to NO_x, reduces Asian pollution influence on US surface ozone in the model by 10–15% or up to 1 ppb.

WRF-Chem Model Simulations of Arizona Dust Storms

Science.gov (United States)

Mohebbi, A.; Chang, H. I.; Hondula, D.

2017-12-01

The online Weather Research and Forecasting model with coupled chemistry module (WRF-Chem) is applied to simulate the transport, deposition and emission of the dust aerosols in an intense dust outbreak event that took place on July 5th, 2011 over Arizona. Goddard Chemistry Aerosol Radiation and Transport (GOCART), Air Force Weather Agency (AFWA), and University of Cologne (UoC) parameterization schemes for dust emission were evaluated. The model was found to simulate well the synoptic meteorological conditions also widely documented in previous studies. The chemistry module performance in reproducing the atmospheric desert dust load was evaluated using the horizontal field of the Aerosol Optical Depth (AOD) from Moderate Resolution Imaging Spectro (MODIS) radiometer Terra/Aqua and Aerosol Robotic Network (AERONET) satellites employing standard Dark Target (DT) and Deep Blue (DB) algorithms. To assess the temporal variability of the dust storm, Particulate Matter mass concentration data (PM10 and PM2.5) from Arizona Department of Environmental Quality (AZDEQ) ground-based air quality stations were used. The promising performance of WRF-Chem indicate that the model is capable of simulating the right timing and loading of a dust event in the planetary-boundary-layer (PBL) which can be used to forecast approaching severe dust events and to communicate an effective early warning.

A Peek into a Cul-De-Sac and a Mews of Martian Dust Storm Activity: Western Hellas and Syria-Claritas Fossae During Mars Year 29

Science.gov (United States)

Heavens, N. G.

2016-12-01

Western Hellas Planitia (WHP) and the region encompassed by Syria Planum and Claritas Fossae are the main centers of textured dust storm activity in Mars's southern low to mid-latitudes. (Texture in this context refers to distinct fine structure at the cloud tops indicative of active lifting.) WHP is a well-known initiation zone for regional and global dust storm activity and often the end point of the Utopia "flushing storm" track. Syria-Claritas Fossae (SCF), too, can be a lifting center in global dust storm activity. Indeed, SCF and the area to its west was the region most denuded of dust by the Mars Year (MY) 25 global dust storm, perhaps suggesting that SCF contained the principal lifting center of the storm. Thus, if the Acidalia and Utopia storm tracks are Mars's dust storm alleys, through which dust storms pass quickly again and again; WHP might be a cul-de-sac and SCF something like a mews, where dust storm activity can enter more or less easily but may not as easily leave. In this presentation, I will focus on dust storm activity in these areas in a typical non-global dust storm year, MY 29. Synthesizing visible imagery by the Mars Color Imager (MARCI) on board Mars Reconnaissance Orbiter (MRO) and Mars Climate Sounder (MCS) also on board MRO, I will consider the climatology, morphology, texture, and vertical structure of dust storm activity in these areas in order to infer their governing dynamics. This investigation has two aims: (1) to understand why these areas are centers of textured dust storm activity; and (2) to connect the characteristics of smaller-scale dust storm activity in these regions to the underlying dynamics in order to understand the role of WHP and SCF in the dynamics of global dust storms. This work is supported by NASA's Mars Data Analysis Program (NNX14AM32G).

Decreased Pulmonary Function in School Children in Western Japan after Exposures to Asian Desert Dusts and Its Association with Interleukin-8

OpenAIRE

Masanari Watanabe; Hisashi Noma; Jun Kurai; Hiroyuki Sano; Rumiko Saito; Satoshi Abe; Yutaka Kimura; Setsuya Aiba; Mitsuo Oshimura; Akira Yamasaki; Eiji Shimizu

2015-01-01

The objective of the study was to investigate the influence of Asian dust storms (ADS) on pulmonary function of school children and the relationship of this effect with interleukin-8. Morning peak expiratory flow (PEF) was measured daily in 399 children from April to May 2012 and in 384 of these children from March to May 2013. The data were analyzed for an association between ADS events and PEF by linear mixed models. Interleukin-8 transcriptional activity was assessed in THP-G8 cells stimul...

An electrified dust storm over the Negev desert, Israel

Science.gov (United States)

Yair, Yoav; Katz, Shai; Yaniv, Roy; Ziv, Baruch; Price, Colin

2016-11-01

We report on atmospheric electrical measurements conducted at the Wise Observatory in Mitzpe-Ramon, Israel (30°35‧N, 34°45‧E) during a large dust storm that occurred over the Eastern Mediterranean region on 10-11 February 2015. The dust was transported from the Sahara, Egypt and the Sinai Peninsula ahead of an approaching Cyprus low. Satellite images show the dust plume covering the Negev desert and Southern Israel and moving north. The concentrations of PM10 particles measured by the air-quality monitoring network of the Israeli Ministry of the Environment in Beer-Sheba reached values > 450 μg m- 3 and the AOT from the AERONET station in Sde-Boker was 1.5 on February 10th. The gradual intensification of the event reached peak concentrations on February 11th of over 1200 μg m- 3 and an AOT of 1.8. Continuous measurements of the fair weather vertical electric field (Ez) and vertical current density (Jz) were conducted at the Wise Observatory with 1 minute temporal resolution. Meteorological data was also recorded at the site. As the dust was advected over the observatory, very large fluctuations in the electrical parameters were registered. From the onset of the dust storm, the Ez values changed between + 1000 and + 8000 V m- 1 while the current density fluctuated between - 10 pA m2 and + 20 pA m2, both on time-scales of a few minutes. These values are significant departures from the average fair-weather values measured at the site, which are ~- 200 V m- 1 and ~ 2 pA m2. The disturbed episodes lasted for several hours on February 10th and the 11th and coincided with local meteorological conditions related to the wind speed and direction, which carried large amounts of dust particles over our observation station. We interpret the rapid changes as caused by the transport of electrically charged dust, carrying an excess of negative charge at lower altitudes.

Study of characterizations of aerosols in a dust storm source region and its influence on Beijing by NAA and ICP-MS

International Nuclear Information System (INIS)

Song Yan; Chai Zhifang; Xu Diandou; Feng Weiyue; Ouyang Hong; Mao Xueying

2005-01-01

Dust storms have caused many problems in the environment, health and climate. For decades, dust storms have occurred frequently in various regions of China. The dust aerosols not only affected the local atmosphere, but also contaminated the atmosphere of the circumjacent regions. Further, they could affect Korea, Japan and even USA via long-range transportation. Many researches related to Chinese dust storms have been reported, however, there are few reports on the chemical components and characters of dust aerosols at their sources. Data on chemical properties of dust storm in the dust source region can help people understand the characteristics of dust storms and their influence on local and other regions. Duolun county (42 degree 13' N, 116 degree 25' E) lies in the southeast of Inner Mongolia, China, in the south of Hunshandake sands (one of the four famous sands in China). Because it is located at windward of Beijing, the dust aerosols can affect Beijing quickly when dust storm occurs. Hence, the study of chemical compositions and elemental abundance patterns of atmospheric particulate matters at Duolun is imperative to understand its influence on Beijing's atmospheric quality. In this work, TSP and PM2.5 samples were collected in Beijing and Duolun, Inner Mongolia, China, in April and May of 2002. Monthly arithmetic averages of the mass concentrations indicated that the pollution of atmospheric particulate matter's (APM) in Duolun was very serious, especially in April. The chemical compositions of total 163 samples were analyzed by INAA and ICP-MS and their origins were identified through Enrichment Factor and Principal Component Analysis. The results showed that the main source of Duolun aerosols was soil dust, and coal combustion constituted the important anthropogenic contribution. The dust events in April and changes of local meteorological conditions were the main reasons for the differences of APM characteristics between April and May. The

Atmospheric Electricity Effects of Eastern Mediterranean Dust Storms

Science.gov (United States)

Katz, Shai; Yair, Yoav; Yaniv, Roy; Price, Colin

2016-04-01

We present atmospheric electrical measurements conducted at the Wise Observatory (WO) in Mizpe-Ramon (30035'N, 34045'E) and Mt. Hermon (30024'N, 35051'E), Israel, during two massive and unique dust storms that occurred over the Eastern Mediterranean region on February 10-11 and September 08-12, 2015. The first event transported Saharan dust from Egypt and the Sinai Peninsula in advance of a warm front of a Cyprus low pressure system. In the second event, dust particles were transported from the Syrian desert, which dominates the north-east border with Iraq, through flow associated with a shallow Persian trough system. In both events the concentrations of PM10 particles measured by the air-quality monitoring network of the Israeli Ministry of the Environment in Beer-Sheba reached values > 2200 μg m-3. Aerosol Optical Thickness (AOT) obtained from the AERONET station in Sde-Boker reached values up to 4.0. The gradual intensification of the first event reached peak values on the February 11th > 1200 μg m-3 and an AOT ~ 1.8, while the second dust storm commenced on September 8th with a sharp increase reaching peak values of 2225 μg m-3 and AOT of 4.0. Measurements of the fair weather vertical electric field (Ez) and of the vertical current density (Jz) were conducted continuously with a 1 minute temporal resolution. During the February event, very large fluctuations in the electrical parameters were measured at the WO. The Ez values changed between +1000 and +8000 V m-1 while the Jz fluctuated between -10 and +20 pA m-2 (this is an order of magnitude larger compared to the fair weather current density of ~2 pA m-2. In contrast, during the September event, Ez values registered at WO were between -430 and +10 V m-1 while the Jz fluctuated between -6 and +3 pA m2. For the September event the Hermon site showed Ez and Jz values fluctuating between -460 and +570 V m-1 and -14.5 and +18 pA m-2 respectively. The electric field and current variability, amplitude and the

Observed trend in Asian dust days in South Korea and its geo-physiographical implications

Science.gov (United States)

Yang, Soohyun; Paik, Kyungrock

2015-04-01

South Korea has experienced significant socio-economic damages by Asian dust (also called Yellow sand or Yellow dust). Asian dust is a wind-driven natural phenomenon that carries fine sand particles along with surface pollutants from semi-arid areas in northern China, Inner Mongolia, the Gobi Desert, and the Taklimakan Desert to the East Asia. Its occurrence requires three necessary conditions: dry soil in source areas, strong ascending air current to lift sand particles up, and intense wind speed to transport the particles. Accordingly, the drier source areas are, the larger amount of source materials for Asian dust becomes. Further, regional wind speed and direction are key elements that determine the influencing boundary and level of damage. In this study, we investigate number of Asian dust days over South Korea. We utilize monthly data over 50 years (from 1961 to 2013) recorded at 12 stations, operated by the Korean Meteorological Administration, which are evenly distributed over the country. We find that annual number of Asian dust days in South Korea tends to increase until early 2000s and the increasing trend is ceased since then. Interestingly, this transition time (early 2000s) matches the time when the surface wind speed trend has reversed (Kim and Paik, 2015). Hence, we hypothesize that occurrence of Asian dust in South Korea can be largely captured by surface wind, instead of air circulation at high altitude. We also hypothesize that the transition in the trend around early 2000s is associated with expansion of cold air system during winter over the East Asia. Detailed analysis to support these findings will be presented. Reference Kim, JC., & Paik, K. (2015). Recent recovery of surface wind speed after decadal decrease: A focus on South Korea. Climate Dynamics, (Under review).

Dust storms over the Arabian Gulf: a possible indicator of climate changes consequences

NARCIS (Netherlands)

Hamza, W.; Enan, M.R.; Al-Hassini, H.; Stuut, J.B.; de-Beer, D.

2011-01-01

Dust storm frequencies and strengths were monitored during 2009 at various locations along the coast of the United Arab Emirates (UAE), as representative sites of the Arabian Gulf marine environment. The results have been compared with a pre-2009 five-year data set. Mineralogical components of dust

Electrical Activity in Martian Dust Storms

Science.gov (United States)

Majid, W.; Arabshahi, S.; Kocz, J.

2016-12-01

Dust storms on Mars are predicted to be capable of producing electrostatic fields and discharges, even larger than those in dust storms on Earth. Such electrical activity poses serious risks to any Human exploration of the planet and the lack of sufficient data to characterize any such activity has been identified by NASA's MEPAG as a key human safety knowledge gap. There are three key elements in the characterization of Martian electrostatic discharges: dependence on Martian environmental conditions, frequency of occurrence, and the strength of the generated electric fields. We will describe a recently deployed detection engine using NASA's Deep Space Network (DSN) to carry out a long term monitoring campaign to search for and characterize the entire Mars hemisphere for powerful discharges during routine tracking of spacecraft at Mars on an entirely non-interfering basis. The resulting knowledge of Mars electrical activity would allow NASA to plan risk mitigation measures to ensure human safety during Mars exploration. In addition, these measurements will also allow us to place limits on presence of oxidants such as H2O2 that may be produced by such discharges, providing another measurement point for models describing Martian atmospheric chemistry and habitability. Because of the continuous Mars telecommunication needs of NASA's Mars-based assets, the DSN is the only instrument in the world that combines long term, high cadence, observing opportunities with large sensitive telescopes, making it a unique asset worldwide in searching for and characterizing electrostatic activity at Mars from the ground.

Asian dust events of April 1998

Science.gov (United States)

Husar, R.B.; Tratt, D.M.; Schichtel, B.A.; Falke, S.R.; Li, F.; Jaffe, D.; Gasso, S.; Gill, T.; Laulainen, N.S.; Lu, F.; Reheis, M.C.; Chun, Y.; Westphal, D.; Holben, B.N.; Gueymard, C.; McKendry, I.; Kuring, N.; Feldman, G.C.; McClain, C.; Frouin, R.J.; Merrill, J.; DuBois, D.; Vignola, F.; Murayama, T.; Nickovic, S.; Wilson, W.E.; Sassen, K.; Sugimoto, N.; Malm, W.C.

2001-01-01

On April 15 and 19, 1998, two intense dust storms were generated over the Gobi desert by springtime low-pressure systems descending from the northwest. The windblown dust was detected and its evolution followed by its yellow color on SeaWiFS satellite images, routine surface-based monitoring, and through serendipitous observations. The April 15 dust cloud was recirculating, and it was removed by a precipitating weather system over east Asia. The April 19 dust cloud crossed the Pacific Ocean in 5 days, subsided to the surface along the mountain ranges between British Columbia and California, and impacted severely the optical and the concentration environments of the region. In east Asia the dust clouds increased the albedo over the cloudless ocean and land by up to 10-20%, but it reduced the near-UV cloud reflectance, causing a yellow coloration of all surfaces. The yellow colored backscattering by the dust eludes a plausible explanation using simple Mie theory with constant refractive index. Over the West Coast the dust layer has increased the spectrally uniform optical depth to about 0.4, reduced the direct solar radiation by 30-40%, doubled the diffuse radiation, and caused a whitish discoloration of the blue sky. On April 29 the average excess surface-level dust aerosol concentration over the valleys of the West Coast was about 20-50 ??g/m3 with local peaks >100 ??g/m3. The dust mass mean diameter was 2-3 ??m, and the dust chemical fingerprints were evident throughout the West Coast and extended to Minnesota. The April 1998 dust event has impacted the surface aerosol concentration 2-4 times more than any other dust event since 1988. The dust events were observed and interpreted by an ad hoc international web-based virtual community. It would be useful to set up a community-supported web-based infrastructure to monitor the global aerosol pattern for such extreme aerosol events, to alert and to inform the interested communities, and to facilitate collaborative

Legal immigrants: invasion of alien microbial communities during winter occurring desert dust storms.

Science.gov (United States)

Weil, Tobias; De Filippo, Carlotta; Albanese, Davide; Donati, Claudio; Pindo, Massimo; Pavarini, Lorenzo; Carotenuto, Federico; Pasqui, Massimiliano; Poto, Luisa; Gabrieli, Jacopo; Barbante, Carlo; Sattler, Birgit; Cavalieri, Duccio; Miglietta, Franco

2017-03-10

A critical aspect regarding the global dispersion of pathogenic microorganisms is associated with atmospheric movement of soil particles. Especially, desert dust storms can transport alien microorganisms over continental scales and can deposit them in sensitive sink habitats. In winter 2014, the largest ever recorded Saharan dust event in Italy was efficiently deposited on the Dolomite Alps and was sealed between dust-free snow. This provided us the unique opportunity to overcome difficulties in separating dust associated from "domestic" microbes and thus, to determine with high precision microorganisms transported exclusively by desert dust. Our metagenomic analysis revealed that sandstorms can move not only fractions but rather large parts of entire microbial communities far away from their area of origin and that this microbiota contains several of the most stress-resistant organisms on Earth, including highly destructive fungal and bacterial pathogens. In particular, we provide first evidence that winter-occurring dust depositions can favor a rapid microbial contamination of sensitive sink habitats after snowmelt. Airborne microbial depositions accompanying extreme meteorological events represent a realistic threat for ecosystem and public health. Therefore, monitoring the spread and persistence of storm-travelling alien microbes is a priority while considering future trajectories of climatic anomalies as well as anthropogenically driven changes in land use in the source regions.

Dust storm events over Delhi: verification of dust AOD forecasts with satellite and surface observations

Science.gov (United States)

Singh, Aditi; Iyengar, Gopal R.; George, John P.

2016-05-01

Thar desert located in northwest part of India is considered as one of the major dust source. Dust storms originate in Thar desert during pre-monsoon season, affects large part of Indo-Gangetic plains. High dust loading causes the deterioration of the ambient air quality and degradation in visibility. Present study focuses on the identification of dust events and verification of the forecast of dust events over Delhi and western part of IG Plains, during the pre-monsoon season of 2015. Three dust events have been identified over Delhi during the study period. For all the selected days, Terra-MODIS AOD at 550 nm are found close to 1.0, while AURA-OMI AI shows high values. Dust AOD forecasts from NCMRWF Unified Model (NCUM) for the three selected dust events are verified against satellite (MODIS) and ground based observations (AERONET). Comparison of observed AODs at 550 nm from MODIS with NCUM predicted AODs reveals that NCUM is able to predict the spatial and temporal distribution of dust AOD, in these cases. Good correlation (~0.67) is obtained between the NCUM predicted dust AODs and location specific observations available from AERONET. Model under-predicted the AODs as compared to the AERONET observations. This may be mainly because the model account for only dust and no anthropogenic activities are considered. The results of the present study emphasize the requirement of more realistic representation of local dust emission in the model both of natural and anthropogenic origin, to improve the forecast of dust from NCUM during the dust events.

Developing Subdomain Allocation Algorithms Based on Spatial and Communicational Constraints to Accelerate Dust Storm Simulation

Science.gov (United States)

Gui, Zhipeng; Yu, Manzhu; Yang, Chaowei; Jiang, Yunfeng; Chen, Songqing; Xia, Jizhe; Huang, Qunying; Liu, Kai; Li, Zhenlong; Hassan, Mohammed Anowarul; Jin, Baoxuan

2016-01-01

Dust storm has serious disastrous impacts on environment, human health, and assets. The developments and applications of dust storm models have contributed significantly to better understand and predict the distribution, intensity and structure of dust storms. However, dust storm simulation is a data and computing intensive process. To improve the computing performance, high performance computing has been widely adopted by dividing the entire study area into multiple subdomains and allocating each subdomain on different computing nodes in a parallel fashion. Inappropriate allocation may introduce imbalanced task loads and unnecessary communications among computing nodes. Therefore, allocation is a key factor that may impact the efficiency of parallel process. An allocation algorithm is expected to consider the computing cost and communication cost for each computing node to minimize total execution time and reduce overall communication cost for the entire simulation. This research introduces three algorithms to optimize the allocation by considering the spatial and communicational constraints: 1) an Integer Linear Programming (ILP) based algorithm from combinational optimization perspective; 2) a K-Means and Kernighan-Lin combined heuristic algorithm (K&K) integrating geometric and coordinate-free methods by merging local and global partitioning; 3) an automatic seeded region growing based geometric and local partitioning algorithm (ASRG). The performance and effectiveness of the three algorithms are compared based on different factors. Further, we adopt the K&K algorithm as the demonstrated algorithm for the experiment of dust model simulation with the non-hydrostatic mesoscale model (NMM-dust) and compared the performance with the MPI default sequential allocation. The results demonstrate that K&K method significantly improves the simulation performance with better subdomain allocation. This method can also be adopted for other relevant atmospheric and numerical

The case study on elemental analyses of Asian dust particles by using an analytical scanning electron microscope

International Nuclear Information System (INIS)

Takeuchi, Jo; Masaki, Kazushige; Emoto, Yuji

2009-01-01

The individual particle analyses of suspended particulate matter (SPM: particles less than 10 μm in size) collected on tape filters during April 17-18, 2006, in Kawasaki, Japan, were carried out. The chemical elements present in aerosol particles were investigated by using a scanning electron microscope with an energy-dispersive X-ray spectrometer. The fraction of chemical elements detected in the particles collected on April 18, 2006, except for S, was in good agreement with that in Asian dust particles from the Loess Plateau, China. S was not detected in Asian dust particles but was detected in the particles collected on April 18, 2006. Therefore, it was concluded that the particles collected in April 18, 2006, in Kawasaki were Asian dust particles transported from the Asian continent, and the absorption of SO 2 or the coagulation of sulfate occurred during the transportation of Asian dust particles. (author)

High Proportions of Sub-micron Particulate Matter in Icelandic Dust Storms in 2015

Science.gov (United States)

Dagsson Waldhauserova, Pavla; Arnalds, Olafur; Olafsson, Haraldur; Magnusdottir, Agnes

2017-04-01

Iceland is extremely active dust region and desert areas of over 44,000 km2 acknowledge Iceland as the largest Arctic and European desert. Frequent dust events, up to 135 dust days annually, transport dust particles far distances towards the Arctic and Europe. Satellite MODIS pictures have revealed dust plumes exceeding 1,000 km. The annual dust deposition was calculated as 40.1 million tons yr-1. Two dust storms were measured in transverse horizontal profile about 90 km far from different dust sources in southwestern Iceland in the summer of 2015. Aerosol monitor DustTrak DRX 8533EP was used to measure PM mass concentrations corresponding to PM1, PM2.5, PM4, PM10 and the total PM15 at several places within the dust plume. Images from camera network operated by the Icelandic Road and Coastal Administration were used to estimate the visibility and spatial extent of measured dust events. A numerical simulation of surface winds was carried out with the numerical model HIRLAM with horizontal resolution of 5 km and used to calculate the total dust flux from the sources. The in situ measurements inside the dust plumes showed that aeolian dust can be very fine. The study highlights that suspended volcanic dust in Iceland causes air pollution with extremely high PM1 concentrations comparable to the polluted urban stations in Europe or Asia rather than reported dust event observations from around the world. The PM1/PM2.5 ratios are generally low during dust storms outside of Iceland, much lower than > 0.9 and PM1/PM10 ratios of 0.34-0.63 found in our study. It shows that Icelandic volcanic dust consists of higher proportion of submicron particles compared to crustal dust. The submicron particles are predicted to travel long distances. Moreover, such submicron particles pose considerable health risk because of high potential for entering the lungs. Icelandic volcanic glass has often fine pipe-vesicular structures known from asbestos and high content of heavy metals. Previous

THE VISUALIZATION METHOD OF THE 3D CONCENTRATION DISTRIBUTION OF ASIAN DUST IN THE GOOGLE EARTH

Directory of Open Access Journals (Sweden)

W. Okuda

2012-07-01

Full Text Available The Asian dust (called "Kosa" in Japan transported from desert areas in the northern China often covers over East Asia in the late winter and spring seasons. In this study, first of all, for dust events observed at various places in Japan on April 1, 2007 and March 21, 2010, the long-range transport simulation of Asian dust from desert areas in the northern China to Japan is carried out. Next, the method for representing 3D dust clouds by means of the image overlay functionality provided in the Google Earth is described. Since it is very difficult to display 3D dust clouds along the curvature of the Earth on the global scale, the 3D dust cloud distributed at the altitude of about 6300m was divided into many thin layers, each of which is the same thickness. After each of layers was transformed to the image layer, each image layer was displayed at the appropriate altitude in the Google Earth. Thus obtained image layers were displayed every an hour in the Google Earth. Finally, it is shown that 3D Asian dust clouds generated by the method described in this study are represented as smooth 3D cloud objects even if we looked at Asian dust clouds transversely in the Google Earth.

Early-Holocene greening of the Afro-Asian dust belt changed sources of mineral dust in West Asia

Science.gov (United States)

Sharifi, Arash; Murphy, Lisa N.; Pourmand, Ali; Clement, Amy C.; Canuel, Elizabeth A.; Naderi Beni, Abdolmajid; Lahijani, Hamid A. K.; Delanghe, Doriane; Ahmady-Birgani, Hesam

2018-01-01

Production, transport and deposition of mineral dust have significant impacts on different components of the Earth systems through time and space. In modern times, dust plumes are associated with their source region(s) using satellite and land-based measurements and trajectory analysis of air masses through time. Reconstruction of past changes in the sources of mineral dust as related to changes in climate, however, must rely on the knowledge of the geochemical and mineralogical composition of modern and paleo-dust, and that of their potential source origins. In this contribution, we present a 13,000-yr record of variations in radiogenic Sr-Nd-Hf isotopes and Rare Earth Element (REE) anomalies as well as dust grain size from an ombrotrophic (rain fed) peat core in NW Iran as proxies of past changes in the sources of dust over the interior of West Asia. Our data shows that although the grain size of dust varies in a narrow range through the entire record, the geochemical fingerprint of dust particles deposited during the low-flux, early Holocene period (11,700-6,000 yr BP) is distinctly different from aerosols deposited during high dust flux periods of the Younger Dryas and the mid-late Holocene (6,000-present). Our findings indicate that the composition of mineral dust deposited at the study site changed as a function of prevailing atmospheric circulation regimes and land exposure throughout the last deglacial period and the Holocene. Simulations of atmospheric circulation over the region show the Northern Hemisphere Summer Westerly Jet was displaced poleward across the study area during the early Holocene when Northern Hemisphere insolation was higher due to the Earth's orbital configuration. This shift, coupled with lower dust emissions simulated based on greening of the Afro-Asian Dust Belt during the early Holocene likely led to potential sources in Central Asia dominating dust export to West Asia during this period. In contrast, the dominant western and

Dust Storm over the Middle East: Retrieval Approach, Source Identification, and Trend Analysis

Science.gov (United States)

Moridnejad, A.; Karimi, N.; Ariya, P. A.

2014-12-01

The Middle East region has been considered to be responsible for approximately 25% of the Earth's global emissions of dust particles. By developing Middle East Dust Index (MEDI) and applying to 70 dust storms characterized on MODIS images and occurred during the period between 2001 and 2012, we herein present a new high resolution mapping of major atmospheric dust source points participating in this region. To assist environmental managers and decision maker in taking proper and prioritized measures, we then categorize identified sources in terms of intensity based on extracted indices for Deep Blue algorithm and also utilize frequency of occurrence approach to find the sensitive sources. In next step, by implementing the spectral mixture analysis on the Landsat TM images (1984 and 2012), a novel desertification map will be presented. The aim is to understand how human perturbations and land-use change have influenced the dust storm points in the region. Preliminary results of this study indicate for the first time that c.a., 39 % of all detected source points are located in this newly anthropogenically desertified area. A large number of low frequency sources are located within or close to the newly desertified areas. These severely desertified regions require immediate concern at a global scale. During next 6 months, further research will be performed to confirm these preliminary results.

Asian dust outflow in the PBL and free atmosphere retrieved by NASA CALIPSO and an assimilated dust transport model

OpenAIRE

Y. Hara; K. Yumimoto; I. Uno; A. Shimizu; N. Sugimoto; Z. Liu; D. M. Winker

2009-01-01

International audience; Three-dimensional structures of Asian dust transport in the planetary boundary layer (PBL) and free atmosphere occurring successively during the end of May 2007 were clarified using results of space-borne backscatter lidar, Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP), and results simulated using a data-assimilated version of a dust transport model (RC4) based on a ground-based NIES lidar network. Assimilated results mitigated overestimation of dust concen...

Large Salt Dust Storms Follow a 30-Year Rainfall Cycle in the Mar Chiquita Lake (Córdoba, Argentina.

Directory of Open Access Journals (Sweden)

Enrique H Bucher

Full Text Available Starting in 2006, a new source of intense salt dust storms developed in Mar Chiquita (Córdoba, Argentina, the largest saline lake in South America. Storms originate from vast mudflats left by a 30-year expansion-retreat cycle of the lake due to changes in the regional rainfall regime. The annual frequency of salt dust storms correlated with the size of the salt mudflats. Events were restricted to the coldest months, and reached up to 800 km from the source. Occurrence of dust storms was associated with specific surface colors and textures easily identifiable in satellite images. High-emission surfaces were characterized by the presence of sodium sulfate hydrous/anhydrous crystals (mirabilite and thenardite, and a superficial and variable water table, which may result in the periodic development of a characteristic "fluffy" surface derived from salt precipitation-dissolution processes. HYSPLIT model simulation estimates a deposition maximum near the sources (of about 2.5 kg/ha/yr, and a decreasing trend from the emission area outwards, except for the relative secondary maximum modeled over the mountain ranges in southern Bolivia and northern Argentina due to an orographic effect. The 2009 total deposition of salt dust generated in Mar Chiquita was estimated at 6.5 million tons.

Detection and monitoring of two dust storm events by multispectral modis images.

Digital Repository Service at National Institute of Oceanography (India)

Mehta P.S.; Kunte, P.D.

of Oman, over Arabian Sea to the coast of Pakistan. The dust storm lasted over the Arabian Sea till 30^th March. MODIS sensors on both Terra and Aqua Satellites captured images of both events. From the difference in emissive/transmissive nature...

Assessment of Vegetation Variation on Primarily Creation Zones of the Dust Storms Around the Euphrates Using Remote Sensing Images

Directory of Open Access Journals (Sweden)

Jamil Amanollahi

2012-06-01

Full Text Available Recently, period frequency and effect domain of the dust storms that enter Iran from Iraq have increased. In this study, in addition to detecting the creation zones of the dust storms, the effect of vegetation cover variation on their creation was investigated using remote sensing. Moderate resolution image Spectroradiometer (MODIS and Landsat Thematic Mapper (TM5 have been utilized to identify the primarily creation zones of the dust storms and to assess the vegetation cover variation, respectively. Vegetation cover variation was studied using Normalized Differences Vegetation Index (NDVI obtained from band 3 and band 4 of the Landsate satellite. The results showed that the surrounding area of the Euphrates in Syria, the desert in the vicinity of this river in Iraq, including the deserts of Alanbar Province, and the north deserts of Saudi Arabia are the primarily creation zones of the dust storms entering west and south west of Iran. The results of NDVI showed that excluding the deserts in the border of Syria and Iraq, the area with very weak vegetation cover have increased between 2.44% and 20.65% from 1991 to 2009. In the meanwhile, the retention pound surface areas in the south deserts of Syria as well as the deserts in its border with Iraq have decreased 6320 and 4397 hectares, respectively. As it can be concluded from the findings, one of the main environmental parameters initiating these dust storms is the decrease in the vegetation cover in their primarily creation zones.

The Effect of Asian Dust Aerosols on Cloud Properties and Radiative Forcing from MODIS and CERES

Science.gov (United States)

Huang, Jianping; Minnis, Patrick; Lin, Bing; Wang, Tianhe; Yi, Yuhong; Hu, Yongxiang; Sun-Mack, Sunny; Ayers, Kirk

2005-01-01

The effects of dust storms on cloud properties and radiative forcing are analyzed over northwestern China from April 2001 to June 2004 using data collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) and Clouds and the Earth's Radiant Energy System (CERES) instruments on the Aqua and Terra satellites. On average, ice cloud effective particle diameter, optical depth and ice water path of the cirrus clouds under dust polluted conditions are 11%, 32.8%, and 42% less, respectively, than those derived from ice clouds in dust-free atmospheric environments. The humidity differences are larger in the dusty region than in the dust-free region, and may be caused by removal of moisture by wet dust precipitation. Due to changes in cloud microphysics, the instantaneous net radiative forcing is reduced from -71.2 W/m2 for dust contaminated clouds to -182.7 W/m2 for dust-free clouds. The reduced cooling effects of dusts may lead to a net warming of 1 W/m2, which, if confirmed, would be the strongest aerosol forcing during later winter and early spring dust storm seasons over the studied region.

Diagnostic evaluation of the Community Earth System Model in simulating mineral dust emission with insight into large-scale dust storm mobilization in the Middle East and North Africa (MENA)

Science.gov (United States)

Parajuli, Sagar Prasad; Yang, Zong-Liang; Lawrence, David M.

2016-06-01

Large amounts of mineral dust are injected into the atmosphere during dust storms, which are common in the Middle East and North Africa (MENA) where most of the global dust hotspots are located. In this work, we present simulations of dust emission using the Community Earth System Model Version 1.2.2 (CESM 1.2.2) and evaluate how well it captures the spatio-temporal characteristics of dust emission in the MENA region with a focus on large-scale dust storm mobilization. We explicitly focus our analysis on the model's two major input parameters that affect the vertical mass flux of dust-surface winds and the soil erodibility factor. We analyze dust emissions in simulations with both prognostic CESM winds and with CESM winds that are nudged towards ERA-Interim reanalysis values. Simulations with three existing erodibility maps and a new observation-based erodibility map are also conducted. We compare the simulated results with MODIS satellite data, MACC reanalysis data, AERONET station data, and CALIPSO 3-d aerosol profile data. The dust emission simulated by CESM, when driven by nudged reanalysis winds, compares reasonably well with observations on daily to monthly time scales despite CESM being a global General Circulation Model. However, considerable bias exists around known high dust source locations in northwest/northeast Africa and over the Arabian Peninsula where recurring large-scale dust storms are common. The new observation-based erodibility map, which can represent anthropogenic dust sources that are not directly represented by existing erodibility maps, shows improved performance in terms of the simulated dust optical depth (DOD) and aerosol optical depth (AOD) compared to existing erodibility maps although the performance of different erodibility maps varies by region.

Dust Storms in North China in 2002: A Case Study of the Low Frequency Oscillation

Institute of Scientific and Technical Information of China (English)

无

2007-01-01

The low frequency oscillation in both hemispheres and its possible role in the dust weather storm events over North China in 2002 are analyzed as a case study. Results show that the Aleutian Low is linked with the Circumpolar Vortex in the Southern Hemisphere on a 30-60-day oscillation, with a weak Circumpolar Vortex tending to deepen the Aleutian Low which may be helpful for the generation of dust storm events.The possible mechanism behind this is the inter-hemispheric interaction of the mean meridional circulation,with the major variability over East Asia. The zonal mean westerly wind at high latitudes of the Southern Hemisphere in the upper level troposphere may lead that of the Northern Hemisphere, which then impacts the local circulation in the Northern Hemisphere. Thus, the low frequency oscillation teleconnection is one possible linkage in the coupling between the Southern Hemisphere circulation and dust events over North China. However, the interannual variation of the low frequency oscillation is unclear.

Chemical composition of PM10 and its in vitro toxicological impacts on lung cells during the Middle Eastern Dust (MED) storms in Ahvaz, Iran.

Science.gov (United States)

Naimabadi, Abolfazl; Ghadiri, Ata; Idani, Esmaeil; Babaei, Ali Akbar; Alavi, Nadali; Shirmardi, Mohammad; Khodadadi, Ali; Marzouni, Mohammad Bagherian; Ankali, Kambiz Ahmadi; Rouhizadeh, Ahmad; Goudarzi, Gholamreza

2016-04-01

Reports on the effects of PM10 from dust storm on lung cells are limited. The main purpose of this study was to investigate the chemical composition and in vitro toxicological impacts of PM10 suspensions, its water-soluble fraction, and the solvent-extractable organics extracted from Middle Eastern Dust storms on the human lung epithelial cell (A549). Samples of dust storms and normal days (PM10 0.05). These results led to the conclusions that dust storm PM10 as well as normal day PM10 could lead to cytotoxicity, and the organic compounds (PAHs) and the insoluble particle-core might be the main contributors to cytotoxicity. Our results showed that cytotoxicity and the risk of PM10 to human lung may be more severe during dust storm than normal days due to inhalation of a higher mass concentration of airborne particles. Further research on PM dangerous fractions and the most responsible components to make cytotoxicity in exposed cells is recommended. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evolution of aerosol chemistry in Xi'an, inland China, during the dust storm period of 2013 - Part 1: Sources, chemical forms and formation mechanisms of nitrate and sulfate

Science.gov (United States)

Wang, G. H.; Cheng, C. L.; Huang, Y.; Tao, J.; Ren, Y. Q.; Wu, F.; Meng, J. J.; Li, J. J.; Cheng, Y. T.; Cao, J. J.; Liu, S. X.; Zhang, T.; Zhang, R.; Chen, Y. B.

2014-11-01

were secondarily produced via this pathway, with the remaining derived from the Gobi desert and Loess Plateau, while SO42- in the event almost entirely originated from the desert regions. Such cases are different from those in the East Asian continental outflow region, where during Asia dust storm events SO42- is secondarily produced and concentrates in sub-micrometer particles as (NH4)2SO4 and/or NH4HSO4. To the best of our knowledge, the current work for the first time revealed an infant state of the East Asian dust ageing process in the regions near the source, which is helpful for researchers to understand the panorama of East Asian dust ageing process from the desert area to the downwind region.

Experimental Constraints On Transparency of The 1052;1040;rtian Atmosphere Out of Dust Storm

Science.gov (United States)

Korablev, O.; Moroz, V. I.; Rodin, A. V.

In the absence of a dust storm so-called permanent dust haze with = 0.2 in the atmo- sphere of Mars determines its thermal structure, as it has been shown by Gierasch and Goody [1972 JAS 29, 400] and is confirmed by modern Mars GCMs that include dust cycle. Dust loading varies substantially with the season and geographic location, and only the data of mapping instruments are adequate to characterize it. Presently, these are the data of thermal IR instruments, benefiting from being insensitive to condensa- tional clouds: TES/MGS and IRTM/Viking. In calm atmospheric conditions (aphelion season) a typical value of 9-µm optical depth 9 of 0.05-0.15 is observed by these instruments [Smith et al. 2000, 2001 JGR 105, 9539; JGR 106, 23929; Martin and Richardson 1993 JGR 98, 10941]. In order to quantify the typical optical depth of the permanent dust haze, we will discuss, among others, the following two questions: 1) How to agree the above values and reliable measurements from the surface (VL, Pathfinder) which give the typical optical depth (out of dust storms) of = 0.5 from one side, and some ground-based observations (in UV-visible range) that frequently reveal < 0.02 on the other side. 2) What is the relationship between 9 and the visi- ble optical depth? Comparison of IRTM and VL measurements (the only simultaneous observations available so far) suggest vis/9 = 2.5, that contradict to vis/9 = 0.9 that follow from IRIS/Mariner 9 mineralogy model, which is confirmed by recent re- analysis of IRIS data.

Real-time observational evidence of changing Asian dust morphology with the mixing of heavy anthropogenic pollution

Science.gov (United States)

Pan, X.; Uno, I.; Wang, Z.; Nishizawa, T.; Sugimoto, N.; Yamamoto, S.; Kobayashi, H.; Sun, Y.; Fu, P.; Tang, X.; Wang, Z.

2017-12-01

Natural mineral dust and heavy anthropogenic pollution and its complex interactions cause significant environmental problems in East Asia. Due to restrictions of observing technique, real-time morphological change in Asian dust particles owing to coating process of anthropogenic pollutants is still statistically unclear. Here, we first used a newly developed, single-particle polarization detector and quantitatively investigate the evolution of the polarization property of backscattering light reflected from dust particle as they were mixing with anthropogenic pollutants in North China. The decrease in observed depolarization ratio is mainly attributed to the decrease of aspect ratio of the dust particles as a result of continuous coating processes. Hygroscopic growth of Calcium nitrate (Ca(NO3)2) on the surface of the dust particles played a vital role, particularly when they are stagnant in the polluted region with high RH conditions. Reliable statistics highlight the significant importance of internally mixed, `quasi-spherical' Asian dust particles, which markedly act as cloud condensation nuclei and exert regional climate change.

Simulating the meteorology and PM10 concentrations in Arizona dust storms using the Weather Research and Forecasting model with Chemistry (Wrf-Chem).

Science.gov (United States)

Hyde, Peter; Mahalov, Alex; Li, Jialun

2018-03-01

Nine dust storms in south-central Arizona were simulated with the Weather Research and Forecasting with Chemistry model (WRF-Chem) at 2 km resolution. The windblown dust emission algorithm was the Air Force Weather Agency model. In comparison with ground-based PM 10 observations, the model unevenly reproduces the dust-storm events. The model adequately estimates the location and timing of the events, but it is unable to precisely replicate the magnitude and timing of the elevated hourly concentrations of particles 10 µm and smaller ([PM 10 ]).Furthermore, the model underestimated [PM 10 ] in highly agricultural Pinal County because it underestimated surface wind speeds and because the model's erodible fractions of the land surface data were too coarse to effectively resolve the active and abandoned agricultural lands. In contrast, the model overestimated [PM 10 ] in western Arizona along the Colorado River because it generated daytime sea breezes (from the nearby Gulf of California) for which the surface-layer speeds were too strong. In Phoenix, AZ, the model's performance depended on the event, with both under- and overestimations partly due to incorrect representation of urban features. Sensitivity tests indicate that [PM 10 ] highly relies on meteorological forcing. Increasing the fraction of erodible surfaces in the Pinal County agricultural areas improved the simulation of [PM 10 ] in that region. Both 24-hr and 1-hr measured [PM 10 ] were, for the most part, and especially in Pinal County, extremely elevated, with the former exceeding the health standard by as much as 10-fold and the latter exceeding health-based guidelines by as much as 70-fold. Monsoonal thunderstorms not only produce elevated [PM 10 ], but also cause urban flash floods and disrupt water resource deliveries. Given the severity and frequency of these dust storms, and conceding that the modeling system applied in this work did not produce the desired agreement between simulations and

Variations in airborne bacterial communities at high altitudes over the Noto Peninsula (Japan) in response to Asian dust events

Science.gov (United States)

Maki, Teruya; Hara, Kazutaka; Iwata, Ayumu; Lee, Kevin C.; Kawai, Kei; Kai, Kenji; Kobayashi, Fumihisa; Pointing, Stephen B.; Archer, Stephen; Hasegawa, Hiroshi; Iwasaka, Yasunobu

2017-10-01

Aerosol particles, including airborne microorganisms, are transported through the free troposphere from the Asian continental area to the downwind area in East Asia and can influence climate changes, ecosystem dynamics, and human health. However, the variations present in airborne bacterial communities in the free troposphere over downwind areas are poorly understood, and there are few studies that provide an in-depth examination of the effects of long-range transport of aerosols (natural and anthropogenic particles) on bacterial variations. In this study, the vertical distributions of airborne bacterial communities at high altitudes were investigated and the bacterial variations were compared between dust events and non-dust events.Aerosols were collected at three altitudes from ground level to the free troposphere (upper level: 3000 or 2500 m; middle level: 1200 or 500 m; and low level: 10 m) during Asian dust events and non-dust events over the Noto Peninsula, Japan, where westerly winds carry aerosols from the Asian continental areas. During Asian dust events, air masses at high altitudes were transported from the Asian continental area by westerly winds, and laser imaging detection and ranging (lidar) data indicated high concentrations of non-spherical particles, suggesting that dust-sand particles were transported from the central desert regions of Asia. The air samples collected during the dust events contained 10-100 times higher concentrations of microscopic fluorescent particles and optical particle counter (OPC) measured particles than in non-dust events. The air masses of non-dust events contained lower amounts of dust-sand particles. Additionally, some air samples showed relatively high levels of black carbon, which were likely transported from the Asian continental coasts. Moreover, during the dust events, microbial particles at altitudes of > 1200 m increased to the concentrations ranging from 1. 2 × 106 to 6. 6 × 106 particles m-3. In contrast

Dust and Biological Aerosols from the Sahara and Asia Influence Precipitation in the Western US

Energy Technology Data Exchange (ETDEWEB)

Creamean, Jessie; Suski, Kaitlyn; Rosenfeld, Daniel; Cazorla, Alberto; DeMott, Paul J.; Sullivan, Ryan C.; White, Allen B.; Ralph, F. M.; Minnis, Patrick; Comstock, Jennifer M.; Tomlinson, Jason M.; Prather, Kimberly

2013-03-29

Winter storms in California’s Sierra Nevada increase seasonal snowpack and provide critical water resources for the state. Thus, the mechanisms influencing precipitation in this region have been the subject of research for decades. Previous studies suggest Asian dust enhances cloud ice and precipitation (1), while few studies consider biological aerosols as an important global source of ice nuclei (IN). Here, we show that dust and biological aerosols transported from as far as the Sahara were present in glaciated high-altitude clouds coincident with elevated IN concentrations and ice-induced precipitation. This study presents the first direct cloud and precipitation measurements showing that Saharan and Asian dust and biological aerosols likely serve as IN and play an important role in orographic precipitation processes over the western United States.

Estimation of radiative effect of a heavy dust storm over northwest China using Fu–Liou model and ground measurements

International Nuclear Information System (INIS)

Wang, Wencai; Huang, Jianping; Zhou, Tian; Bi, Jianrong; Lin, Lei; Chen, Yonghang; Huang, Zhongwei; Su, Jing

2013-01-01

A heavy dust storm that occurred in Northwestern China during April 24–30 2010 was studied using observational data along with the Fu–Liou radiative transfer model. The dust storm was originated from Mongolia and affected more than 10 provinces of China. Our results showed that dust aerosols have a significant impact on the radiative energy budget. At Minqin (102.959°E, 38.607°N) and Semi-Arid Climate and Environment Observatory of Lanzhou University (SACOL, 104.13°E, 35.95°N) sites, the net radiative forcing (RF) ranged from 5.93 to 35.7 W m −2 at the top of the atmosphere (TOA), −6.3 to −30.94 W m −2 at surface, and 16.77 to 56.32 W m −2 in the atmosphere. The maximum net radiative heating rate reached 5.89 K at 1.5 km on 24 April at the Minqin station and 4.46 K at 2.2 km on 29 April at the SACOL station. Our results also indicated that the radiative effect of dust aerosols is affected by aerosol optical depth (AOD), single-scattering albedo (SSA) and surface albedo. Modifications of the radiative energy budget by dust aerosols may have important implications for atmospheric circulation and regional climate. -- Highlights: ► Dust aerosols' optical properties and radiative effects were investigated. ► We have surface observations on Minqin and SACOL where heavy dust storm occurred. ► Accurate input parameters for model were acquired from ground-based measurements. ► Aerosol's optical properties may have changed when transported

Evolution of trace elements in the planetary boundary layer in southern China: Effects of dust storms and aerosol-cloud interactions

Science.gov (United States)

Li, Tao; Wang, Yan; Zhou, Jie; Wang, Tao; Ding, Aijun; Nie, Wei; Xue, Likun; Wang, Xinfeng; Wang, Wenxing

2017-03-01

Aerosols and cloud water were analyzed at a mountaintop in the planetary boundary layer in southern China during March-May 2009, when two Asian dust storms occurred, to investigate the effects of aerosol-cloud interactions (ACIs) on chemical evolution of atmospheric trace elements. Fe, Al, and Zn predominated in both coarse and fine aerosols, followed by high concentrations of toxic Pb, As, and Cd. Most of these aerosol trace elements, which were affected by dust storms, exhibited various increases in concentrations but consistent decreases in solubility. Zn, Fe, Al, and Pb were the most abundant trace elements in cloud water. The trace element concentrations exhibited logarithmic inverse relationships with the cloud liquid water content and were found highly pH dependent with minimum concentrations at the threshold of pH 5.0. The calculation of Visual MINTEQ model showed that 80.7-96.3% of Fe(II), Zn(II), Pb(II), and Cu(II) existed in divalent free ions, while 71.7% of Fe(III) and 71.5% of Al(III) were complexed by oxalate and fluoride, respectively. ACIs could markedly change the speciation distributions of trace elements in cloud water by pH modification. The in-cloud scavenging of aerosol trace elements likely reached a peak after the first 2-3 h of cloud processing, with scavenging ratios between 0.12 for Cr and 0.57 for Pb. The increases of the trace element solubility (4-33%) were determined in both in-cloud aerosols and postcloud aerosols. These results indicated the significant importance of aerosol-cloud interactions to the evolution of trace elements during the first several cloud condensation/evaporation cycles.

Single-particle characterization of 'Asian Dust' certified reference materials using low-Z particle electron probe X-ray microanalysis

International Nuclear Information System (INIS)

Hwang, Hee Jin; Ro, Chul-Un

2006-01-01

In order to clearly elucidate whether Asian Dust particles experience chemical modification during long-range transport, it is necessary to characterize soil particles where Asian Dust particles originate. If chemical compositions of source soil particles are well characterized, then chemical compositions of Asian Dust particles collected outside source regions can be compared with those of source soil particles in order to find out the occurrence of chemical modification. Asian Dust particles are chemically and morphologically heterogeneous, and thus the average composition and the average aerodynamic diameter (obtainable by bulk analysis) are not much relevant if the chemical modifications of the particles must be followed. The major elemental composition and abundance of the particle types that are potential subjects of chemical modification can only be obtained using single-particle analysis. A single particle analytical technique, named low-Z particle electron probe X-ray microanalysis (low-Z particle EPMA), was applied to characterize two certified reference materials (CRMs) for Asian Dust particles, which were collected from a loess plateau area and a desert of China. The CRMs were defined by bulk analyses to provide certified concentrations for 13 chemical elements. Using the low-Z particle EPMA technique, the concentrations of major chemical species such as aluminosilicates, SiO 2 , CaCO 3 , and carbonaceous species were obtained. Elemental concentrations obtained by the low-Z particle EPMA are close to the certified values, with considering that the single particle and bulk analyses employ very different approaches. There are still some discrepancies between those concentration values, resulting from analyses of particles with different sizes, different sample amounts analyzed, and uncertainties involved in the single particle analysis

Reply to Comment by Xu et al. on "Sr-Nd isotope composition and clay mineral assemblages in eolian dust from the central Philippine Sea over the last 600 kyr: Implications for the transport mechanism of Asian dust" by Seo et al.

Science.gov (United States)

Seo, Inah; Lee, Yong Il; Yoo, Chan Min; Kim, Hyung Jeek; Hyeong, Kiseong

2016-12-01

Against Xu et al. (2016), who argued that East Asian Desert (EAD) dust that traveled on East Asian Winter Monsoon winds dominates over Central Asian Desert (CAD) dust in the Philippine Sea with presentation of additional data, we reconfirm Seo et al.'s (2014) conclusion that CAD dust carried on the Prevailing Westerlies and Trade Winds dominates over EAD dust in overall dust budget of the central Philippine Sea. The relative contribution of dust from EADs and CADs using clay mineral composition should be evaluated with elimination of mineralogical contribution from the volcanic end-member which is enriched in kaolinite and overestimate the contribution of EAD dust.

The global dispersion of pathogenic microorganisms by dust storms and its relevance to agriculture: Chapter 1

Science.gov (United States)

Gonzalez-Martin, Cristina; Teigell-Perez, Nuria; Valladares, Basilio; Griffin, Dale W.

2014-01-01

Dust storms move an estimated 500–5000 Tg of soil through Earth’s atmosphere every year. Dust-storm transport of topsoils may have positive effects such as fertilization of aquatic and terrestrial ecosystems and the evolution of soils in proximal and distal environments. Negative effects may include the stripping of nutrient-rich topsoils from source regions, sandblasting of plant life in downwind environments, the fertilization of harmful algal blooms, and the transport of toxins (e.g., metals, pesticides, herbicides, etc.) and pathogenic microorganisms. With respect to the long-range dispersion of microorganisms and more specifically pathogens, research is just beginning to demonstrate the quantity and diversity of organisms that can survive this type of transport. Most studies to date have utilized different assays to identify microorganisms and microbial communities using predominately culture-based, and more recently nonculture-based, methodologies. There is a clear need for international-scale research efforts that apply standardized methods to advance this field of science. Here we present a review of dust-borne microorganisms with a focus on their relevance to agronomy.

Size-segregated fluxes of mineral dust from a desert area of northern China by eddy covariance

Directory of Open Access Journals (Sweden)

G. Fratini

2007-06-01

Full Text Available Mineral dust emission accounts for a substantial portion of particles present in the troposphere. It is emitted mostly from desert areas, mainly through intense storm episodes. The aim of this work was to quantify size-segregated fluxes of mineral dust particles emitted during storm events occurring in desert areas of northern China (Alashan desert, Inner Mongolia, known to act as one of the strongest sources of mineral dust particles in the Asian continent. Long-range transport of mineral dust emitted in this area is responsible for the high particle concentrations reached in densely populated areas, including the city of Beijing. Based on a theoretical analysis, an eddy covariance system was built to get size-segregated fluxes of mineral dust particles with optical diameters ranging between 0.26 and 7.00 µm. The system was optimised to measure fluxes under intense storm event conditions. It was tested in two sites located in the Chinese portion of the Gobi desert. During the field campaign, an intense wind erosion event, classified as a "weak dust storm", was recorded in one of them. Data obtained during this event indicate that particle number fluxes were dominated by the finer fraction, whereas in terms of mass, coarser particle accounted for the largest portion. It was found that during the storm event, ratios of size-segregated particle mass fluxes remained substantially constant and a simple parameterization of particle emission from total mass fluxes was possible. A strong correlation was also found between particle mass fluxes and the friction velocity. This relationship is extremely useful to investigate mechanisms of particle formation by wind erosion.

Oxidant enhancement in martian dust devils and storms: implications for life and habitability.

Science.gov (United States)

Atreya, Sushil K; Wong, Ah-San; Renno, Nilton O; Farrell, William M; Delory, Gregory T; Sentman, Davis D; Cummer, Steven A; Marshall, John R; Rafkin, Scot C R; Catling, David C

2006-06-01

We investigate a new mechanism for producing oxidants, especially hydrogen peroxide (H2O2), on Mars. Large-scale electrostatic fields generated by charged sand and dust in the martian dust devils and storms, as well as during normal saltation, can induce chemical changes near and above the surface of Mars. The most dramatic effect is found in the production of H2O2 whose atmospheric abundance in the "vapor" phase can exceed 200 times that produced by photochemistry alone. With large electric fields, H2O2 abundance gets large enough for condensation to occur, followed by precipitation out of the atmosphere. Large quantities of H2O2 would then be adsorbed into the regolith, either as solid H2O2 "dust" or as re-evaporated vapor if the solid does not survive as it diffuses from its production region close to the surface. We suggest that this H2O2, or another superoxide processed from it in the surface, may be responsible for scavenging organic material from Mars. The presence of H2O2 in the surface could also accelerate the loss of methane from the atmosphere, thus requiring a larger source for maintaining a steady-state abundance of methane on Mars. The surface oxidants, together with storm electric fields and the harmful ultraviolet radiation that readily passes through the thin martian atmosphere, are likely to render the surface of Mars inhospitable to life as we know it.

Chemical composition of PM_1_0 and its in vitro toxicological impacts on lung cells during the Middle Eastern Dust (MED) storms in Ahvaz, Iran

International Nuclear Information System (INIS)

Naimabadi, Abolfazl; Ghadiri, Ata; Idani, Esmaeil; Babaei, Ali Akbar; Alavi, Nadali; Shirmardi, Mohammad; Khodadadi, Ali

2016-01-01

Reports on the effects of PM_1_0 from dust storm on lung cells are limited. The main purpose of this study was to investigate the chemical composition and in vitro toxicological impacts of PM_1_0 suspensions, its water-soluble fraction, and the solvent-extractable organics extracted from Middle Eastern Dust storms on the human lung epithelial cell (A549). Samples of dust storms and normal days (PM_1_0   0.05). These results led to the conclusions that dust storm PM_1_0 as well as normal day PM_1_0 could lead to cytotoxicity, and the organic compounds (PAH_s) and the insoluble particle-core might be the main contributors to cytotoxicity. Our results showed that cytotoxicity and the risk of PM_1_0 to human lung may be more severe during dust storm than normal days due to inhalation of a higher mass concentration of airborne particles. Further research on PM dangerous fractions and the most responsible components to make cytotoxicity in exposed cells is recommended. - Highlights: • Chemical compositions of PM_1_0 during normal and dust event days were obtained. • Heavy metal concentrations in dusty conditions were higher than normal days. • PM_1_0 caused a decrease in the cell viability and an increase in LDH in supernatant. • Water-soluble fraction had severe cytotoxicity than solvent extractable organics. • Higher mass concentrations of PM_1_0 may contribute to more severe cytotoxicity. - Inhalation of higher mass concentration of PM during the MED storms may contribute to more severe cytotoxicity than normal days.

Use of SEVIRI images and derived products in a WMO Sand and dust Storm Warning System

Energy Technology Data Exchange (ETDEWEB)

MartInez, M A; Ruiz, J; Cuevas, E [Agencia Estatal de MeteorologIa (AEMET) (Spain)], E-mail: mig@inm.es

2009-03-01

The Visible/IR images of SEVIRI (Spinning Enhanced Visible and Infrared Imager), on board Meteosat Second Generation (MSG) satellites, are used to monitor dust events. Satellite-based detection of dust is a difficult problem due in part to the observing-system limitations. The main difficulty is that the dust can be confused with water/ice clouds. SEVIRI is not as optimal for the viewing of dust as SEAWIFS or MODIS, due to the fact that both of them count with additional short-wavelength channels. However, the SEVIRI 15-minute loop images can detect small dust plumes as well as subtle changes from one image to the next. A description of how the AEMET, former INM, is developing the environment to support MSG satellite imagery to the WMO/GEO Sand and Dust Storm Warning System (SDS WS) for Europe, Africa and Middle East Regional Centre will be briefly presented, together with some on-going operational developments to best monitor dust events.

Diagnosis of the Relationship between Dust Storms over the Sahara Desert and Dust Deposit or Coloured Rain in the South Balkans

Directory of Open Access Journals (Sweden)

N. G. Prezerakos

2010-01-01

Full Text Available The main objects of study in this paper are the synoptic scale atmospheric circulation systems associated with the rather frequent phenomenon of coloured rain and the very rare phenomenon of dust or sand deposits from a Saharan sandstorm triggered by a developing strong depression. Analysis of two such cases revealed that two days before the occurrence of the coloured rain or the dust deposits over Greece a sand storm appeared over the north-western Sahara desert. The flow in the entire troposphere is southerly/south-westerly with an upward vertical motion regime. If the atmospheric conditions over Greece favour rain then this rain contains a part of the dust cloud while the rest is drawn away downstream adopting a light yellow colour. In cases where the atmospheric circulation on the route of the dust cloud trajectories is not intensively anticyclonic dust deposits can occur on the surface long far from the region of the dust origin. Such was the case on 4th April, 1988, when significant synoptic-scale subsidence occurred over Italy and towards Greece. The upper air data, in the form of synoptic maps, illustrate in detail the synoptic-scale atmospheric circulations associated with the emission-transport-deposition and confirm the transportation of dust particles.

Biogeochemical Impact of Long-Range Transported Dust over Northern South China Sea

Science.gov (United States)

Tsay, Si-Chee; Wang, S. H.; Hsu, N. C.

2011-01-01

Transpacific transport and impact of Asian dust aerosols have been well documented (e.g., results from ACE-Asia and regional follow-on campaigns), but little is known about dust invasion to the South China Sea (SCS). On 19-21 March 2010, a fierce Asian dust storm affected large areas from the Gobi deserts to the West Pacific, including Taiwan and Hong Kong. As a pilot study of the 7-SEAS (Seven South East Asian Studies) in the northern SCS, detailed characteristics of long-range transported dust aerosols were first observed by a comprehensive set of ground-based instruments deployed at the Dongsha islands (20deg42'52" N, 116deg43'51" E). Aerosol measurements such as particle mass concentrations, size distribution, optical properties, hygroscopicity, and vertical profiles help illustrate the evolution of this dust outbreak. Our results indicate that these dust particles were mixed with anthropogenic and marine aerosols, and transported near the surface. Satellite assessment of biogeochemical impact of dust deposition into open oceans is hindered by our current inability in retrieving areal dust properties and ocean colors over an extensive period of time, particularly under the influence of cloudy conditions. In this paper, we analyze the changes of retrieved Chlorophyll-a (Chl-a) concentration over the northern SCS, considered as oligotophic waters in the spring, from long-term SeaWiFS measurements since 1997. Over the past decade, six long-range transported dust events are identified based on spatiotemporal evolutions of PM10 measurements from regional monitoring stations, with the aid of trajectory analysis. Multi-year composites of Chl-a imagery for dust event and non-dust background during March-April are applied to overcome insufficient retrievals of Chl-a due to cloudy environment. Due to anthropogenic modification within a shallow boundary layer off the densely populated and industrial southeast coast of China, the iron ion activation of deliquescent dust

Raman lidar measurement of water vapor and ice clouds associated with Asian dust layer over Tsukuba, Japan

Science.gov (United States)

Sakai, Tetsu; Nagai, Tomohiro; Nakazato, Masahisa; Matsumura, Takatsugu

2004-03-01

The vertical distributions of particle extinction, backscattering, depolarization, and water vapor mixing ratio were measured using a Raman lidar over Tsukuba (36.1°N, 140.1°E), Japan, on 23-24 April 2001. Ice clouds associated with the Asian dust layer were observed at an altitude of ~6-9 km. The relative humidities in the cloud layer were close to the ice saturation values and the temperature at the top of the cloud layer was ~-35°C, suggesting that the Asian dust acted as ice nuclei at the high temperatures. The meteorological analysis suggested that the ice-saturated region was formed near the top of the dust layer where the moist air ascended in slantwise fashion above the cold-frontal zone associated with extratropical cyclone.

Properties of a local dust storm on Mars' Atlantis Chaos by means of radiative transfer modeling.

Science.gov (United States)

Oliva, Fabrizio; Altieri, Francesca; Geminale, Anna; Bellucci, Giancarlo; D'Aversa, Emiliano; Carrozzo, Giacomo; Sindoni, Giuseppe; Grassi, Davide

2017-04-01

In this study we present the analysis of the dust properties in a local storm imaged in the Atlantis Chaos region on Mars by the OMEGA spectrometer (Bibring et al., 2004) on March 2nd 2005 (ORB1441_5). By means of an inverse radiative transfer code we study the dust properties across the region and try to infer the connection be-tween the local storm dynamics and the orography. OMEGA is a visible and near-IR mapping spectrometer, operating in the spectral range 0.38-5.1 μm with three separate channels with different spectral resolution. The instrument's IFOV is 1.2 mrad. To analyze the storm properties we have used the inverse radiative transfer model MITRA (Oliva et al., 2016; Sindoni et al., 2013) to retrieve the effective radius reff, the optical depth at 880 nm τ880 and the top pressure tp of the dust layer. We used the Mars Climate Database (MCD, Forget et al., 1999) to obtain the atmospheric properties of the studied region to be used as input in our model. Moreover we used the optical constants from Wolff et al. (2009) to describe the dust composition. The properties from the surface have been obtained by ap-plying the SAS method (Geminale et al., 2015) to observations of the same region relatively clear from dust. All retrievals have been performed in the spectral range 500 ÷ 2500 nm. Here we describe the result from our analysis carried out on selected regions of the storm and characterized by a different optical depth of the dust. Aknowledgements: This study has been performed within the UPWARDS project and funded in the context of the European Union's Horizon 2020 Programme (H2020-Compet-08-2014), grant agreement UPWARDS-633127. References: Bibring, J-P. et al., 2004. OMEGA: Observatoire pour la Minéralogie, l'Eau, les Glaces et l'Activité. Mars Express: the scientific payload, Ed. by Andrew Wilson, scientific coordination: Agustin Chicarro. ESA SP-1240, Noordwijk, Netherlands: ESA Publications Division, ISBN 92-9092-556-6, 2004, p. 37 - 49. Forget

Deposition of 137Cs in Rokkasho, Japan and its relation to Asian dust

International Nuclear Information System (INIS)

Akata, Naofumi; Hasegawa, Hidenao; Kawabata, Hitoshi; Chikuchi, Yuki; Sato, Tadahiro; Ohtsuka, Yoshihito; Kondo, Kunio; Hisamatsu, Shun'ichi

2007-01-01

Biweekly atmospheric depositions of 137 Cs were measured in Rokkasho, Aomori, Japan from March 2000 to March 2006 to study recent 137 Cs deposition. Although the deposition level was generally lower than the detectable limit, deposition samples collected in spring occasionally had measurable levels of 137 Cs. The annual 137 Cs deposition from 2001 to 2005 was 0.04-0.69 Bq m -2 with a mean value of 0.27 Bq m -2 . Depositions of insoluble Al, Fe and Ti were strongly correlated with the 137 Cs deposition, suggesting that suspension of soil particles was the main source of the recent 137 Cs deposition. Asian dust events were coincident with some of the significant 137 Cs depositions in spring. It was found that the ratios of 137 Cs/Al and Fe/Al could be used as indices for discriminating Asian dust from suspension of the local surface soil. Backward trajectory analysis suggested southern Mongolian and northeastern China regions as sources of the significant 137 Cs depositions

Characterization of atmospheric bioaerosols along the transport pathway of Asian dust during the Dust-Bioaerosol 2016 Campaign

Science.gov (United States)

Tang, Kai; Huang, Zhongwei; Huang, Jianping; Maki, Teruya; Zhang, Shuang; Shimizu, Atsushi; Ma, Xiaojun; Shi, Jinsen; Bi, Jianrong; Zhou, Tian; Wang, Guoyin; Zhang, Lei

2018-05-01

Previous studies have shown that bioaerosols are injected into the atmosphere during dust events. These bioaerosols may affect leeward ecosystems, human health, and agricultural productivity and may even induce climate change. However, bioaerosol dynamics have rarely been investigated along the transport pathway of Asian dust, especially in China where dust events affect huge areas and massive numbers of people. Given this situation, the Dust-Bioaerosol (DuBi) Campaign was carried out over northern China, and the effects of dust events on the amount and diversity of bioaerosols were investigated. The results indicate that the number of bacteria showed remarkable increases during the dust events, and the diversity of the bacterial communities also increased significantly, as determined by means of microscopic observations with 4,6-diamidino-2-phenylindole (DAPI) staining and MiSeq sequencing analysis. These results indicate that dust clouds can carry many bacteria of various types into downwind regions and may have potentially important impacts on ecological environments and climate change. The abundances of DAPI-stained bacteria in the dust samples were 1 to 2 orders of magnitude greater than those in the non-dust samples and reached 105-106 particles m-3. Moreover, the concentration ratios of DAPI-stained bacteria to yellow fluorescent particles increased from 5.1 % ± 6.3 % (non-dust samples) to 9.8 % ± 6.3 % (dust samples). A beta diversity analysis of the bacterial communities demonstrated the distinct clustering of separate prokaryotic communities in the dust and non-dust samples. Actinobacteria, Bacteroidetes, and Proteobacteria remained the dominant phyla in all samples. As for Erenhot, the relative abundances of Acidobacteria and Chloroflexi had a remarkable rise in dust events. In contrast, the relative abundances of Acidobacteria and Chloroflexi in non-dust samples of R-DzToUb were greater than those in dust samples. Alphaproteobacteria made the major

PM10 concentration levels at an urban and background site in Cyprus: the impact of urban sources and dust storms.

Science.gov (United States)

Achilleos, Souzana; Evans, John S; Yiallouros, Panayiotis K; Kleanthous, Savvas; Schwartz, Joel; Koutrakis, Petros

2014-12-01

Air quality in Cyprus is influenced by both local and transported pollution, including desert dust storms. We examined PM10 concentration data collected in Nicosia (urban representative) from April 1, 1993, through December 11, 2008, and in Ayia Marina (rural background representative) from January 1, 1999, through December 31, 2008. Measurements were conducted using a Tapered Element Oscillating Micro-balance (TEOM). PM10 concentrations, meteorological records, and satellite data were used to identify dust storm days. We investigated long-term trends using a Generalized Additive Model (GAM) after controlling for day of week, month, temperature, wind speed, and relative humidity. In Nicosia, annual PM10 concentrations ranged from 50.4 to 63.8 μg/m3 and exceeded the EU annual standard limit enacted in 2005 of 40 μg/m3 every year A large, statistically significant impact of urban sources (defined as the difference between urban and background levels) was seen in Nicosia over the period 2000-2008, and was highest during traffic hours, weekdays, cold months, and low wind conditions. Our estimate of the mean (standard error) contribution of urban sources to the daily ambient PM10 was 24.0 (0.4) μg/m3. The study of yearly trends showed that PM10 levels in Nicosia decreased from 59.4 μg/m3 in 1993 to 49.0 μg/m3 in 2008, probably in part as a result of traffic emission control policies in Cyprus. In Ayia Marina, annual concentrations ranged from 27.3 to 35.6 μg/m3, and no obvious time trends were observed. The levels measured at the Cyprus background site are comparable to background concentrations reported in other Eastern Mediterranean countries. Average daily PM10 concentrations during desert dust storms were around 100 μg/m3 since 2000 and much higher in earlier years. Despite the large impact ofdust storms and their increasing frequency over time, dust storms were responsible for a small fraction of the exceedances of the daily PM10 limit. Implications: This

Preliminary studies on applications of micro-PIXE to atmospheric aerosols

International Nuclear Information System (INIS)

Kasahara, M.; Ma, C.-J.; Kamiya, T.; Sakai, T.

2001-01-01

To characterize the physical and chemical properties of the individual aerosol particles during Asian dust storm in Japan, micro-PIXE technique was applied in this study. Aerosol particles were sampled in Kyoto, Japan from the middle of March to the end of April 1999. Mass concentration in Asian dust storm events was roughly 3-5 times higher than that of the highest concentration measured in non-Asian dust storm seasons. Single particles were generally sharp-edged and irregular in shape and contained mostly crustal elements such as Si, Fe and Ca. Although in soils of the desert and loess areas in northwest of China S and Cl were not detected, significant concentrations of S and Cl were detected in coarse fraction during Asian dust storm event. Nearly all single particles in the coarse fraction existed as a mixed state of soil components and S

Possible influences of Asian dust aerosols on cloud properties and radiative forcing observed from MODIS and CERES

Science.gov (United States)

Huang, Jianping; Minnis, Patrick; Lin, Bing; Wang, Tianhe; Yi, Yuhong; Hu, Yongxiang; Sun-Mack, Sunny; Ayers, Kirk

2006-03-01

The effects of dust storms on cloud properties and Radiative Forcing (RF) are analyzed over Northwestern China from April 2001 to June 2004 using data collected by the MODerate Resolution Imaging Spectroradiometer (MODIS) and Clouds and the Earth's Radiant Energy System (CERES) instruments on the Aqua and Terra satellites. On average, ice cloud effective particle diameter, optical depth and ice water path of cirrus clouds under dust polluted conditions are 11%, 32.8%, and 42% less, respectively, than those derived from ice clouds in dust-free atmospheric environments. Due to changes in cloud microphysics, the instantaneous net RF is increased from -161.6 W/m2 for dust-free clouds to -118.6 W/m2 for dust-contaminated clouds.

The Influence of Asian Dust, Haze, Mist, and Fog on Hospital Visits for Airway Diseases.

Science.gov (United States)

Park, Jinkyeong; Lim, Myoung Nam; Hong, Yoonki; Kim, Woo Jin

2015-10-01

Asian dust is known to have harmful effects on the respiratory system. Respiratory conditions are also influenced by environmental conditions regardless of the presence of pollutants. The same pollutant can have different effects on the airway when the air is dry compared with when it is humid. We investigated hospital visits for chronic obstructive pulmonary disease (COPD) and asthma in relation to the environmental conditions. We conducted a retrospective study using the Korean National Health Insurance Service claims database of patients who visited hospitals in Chuncheon between January 2006 and April 2012. Asian dust, haze, mist, and fog days were determined using reports from the Korea Meteorological Administration. Hospital visits for asthma or COPD on the index days were compared with the comparison days. We used two-way case-crossover techniques with one to two matching. The mean hospital visits for asthma and COPD were 59.37 ± 34.01 and 10.04 ± 6.18 per day, respectively. Hospital visits for asthma significantly increased at lag0 and lag1 for Asian dust (relative risk [RR], 1.10; 95% confidence interval [CI], 1.01-1.19; pfog (RR, 0.85; 95% CI, 0.75-0.97; pfog, which occur in humid air conditions, showed the opposite effects on airway diseases, after adjusting to the pollutants. It would require more research to investigate the effects of various air conditions on airway diseases.

Relationship between mortality and fine particles during Asian dust, smog-Asian dust, and smog days in Korea.

Science.gov (United States)

Kim, Hyun-Sun; Kim, Dong-Sik; Kim, Ho; Yi, Seung-Muk

2012-01-01

This study examined the association between all-cause/cardiovascular mortality and PM(2.5) as related to Asian dust (AD), smog-AD, smog, and nonevent days and evaluated the differential risks according to specific events for mortality. The daily records of all-cause/cardiovascular mortality and PM(2.5) from March to May 2003-2006 in Seoul, Korea, were used as independent and dependent variables. Differences in the event effects were assessed using a time-series analysis. Both all-cause and cardiovascular mortalities were significantly associated with PM(2.5) during smog-AD and AD days only. Differences in chemical composition emerging during long-range transport to Korea may explain these observations, especially as regards secondary aerosol, metal-sulfate/or nitrate, and metallic components. These results suggest that exposure to PM(2.5) during specific events is differentially associated with human mortality and that changes in the chemical composition of PM(2.5), occurring during long-range transport, represent important factors in such differential effects on health.

Impact of Middle Eastern dust storms on indoor and outdoor composition of bioaerosol

Science.gov (United States)

Soleimani, Zahra; Goudarzi, Gholamreza; Sorooshian, Armin; Marzouni, Mohammad Bagherian; Maleki, Heidar

2016-08-01

The presence of microbes in airborne aerosol particles, especially dust, is a major public health concern in desert regions. This study is the first of its kind to examine the effect of dust storms on indoor and outdoor microbial air quality at a hospital on the western side of Iran (city of Ahvaz), which is notorious for being highly vulnerable to dust emissions. Air samples were collected inside and outside of the hospital environment for six months, with the unique advantage of this study being that the region and duration of measurements allow for a clear comparison between dusty and normal days. On normal days, the average concentrations (outdoor/indoor) of bacteria and fungi were 423/329 cfu m-3 and 596/386 cfu m-3, respectively, which increased to 1257/406 cfu m-3 and 1116/550 cfu m-3 on dust event days. Indoor/Outdoor ratios for bacteria and fungi are lower on dust event days (0.26-0.60) versus normal days (0.44-0.95). Bacillus spp., Micrococcus spp., Streptomyces spp., and Staphylococcus spp. were the dominant bacteria both indoors and outdoors on normal and dust event days. Gram positive bacteria exhibited higher concentrations than Gram negative bacteria in both outdoor and indoor air samples as well as during both normal and dust event days. The data suggest that Gram positive bacteria are more resistant to undesirable outdoor conditions (e.g., high incident solar radiation) as compared to Gram negative ones. These results have implications for other populated arid regions where more stringent control of indoor air quality can greatly benefit public health.

Spatial and temporal distributions of Martian north polar cold spots before, during, and after the global dust storm of 2001

Science.gov (United States)

Cornwall, C.; Titus, T.N.

2009-01-01

In the 1970s, Mariner and Viking observed features in the Mars northern polar region that were a few hundred kilometers in diameter with 20 fj,m brightness temperatures as low as 130 K (considerably below C02 ice sublimation temperatures). Over the past decade, studies have shown that these areas (commonly called "cold spots") are usually due to emissivity effects of frost deposits and occasionally to active C02 snowstorms. Three Mars years of Mars Global Surveyor Thermal Emission Spectrometer data were used to observe autumn and wintertime cold spot activity within the polar regions. Many cold spots formed on or near scarps of the perennial cap, probably induced by adiabatic cooling due to orographic lifting. These topographically associated cold spots were often smaller than those that were not associated with topography. We determined that initial grain sizes within the cold spots were on the order of a few millimeters, assuming the snow was uncontaminated by dust or water ice. On average, the half-life of the cold spots was 5 Julian days. The Mars global dust storm in 2001 significantly affected cold spot activity in the north polar region. Though overall perennial cap cold spot activity seemed unaffected, the distribution of cold spots did change by a decrease in the number of topographically associated cold spots and an increase in those not associated with topography. We propose that the global dust storm affected the processes that form cold spots and discuss how the global dust storm may have affected these processes. ?? 2009 by the American Geophysical Union.

Dust, Pollution, and Biomass Burning Aerosols in Asian Pacific: A Column Surface/Satellite Perspective

Science.gov (United States)

Tsay, Si-Chee; Lau, William K. M. (Technical Monitor)

2002-01-01

Many recent field experiments are designed to study the compelling variability in spatial and temporal scale of both pollution-derived and naturally occurring aerosols, which often exist in high concentrations over eastern/southeastern Asia and along the rim of the western Pacific. For example, the phase-I of ACE-Asia was conducted from March-May 2001 in the vicinity of the Gobi desert, East Coast of China, Yellow Sea, Korea, and Japan, along the pathway of Kosa (severe events that blanket East Asia with yellow desert dust, peaked in the Spring season). Asian dust typically originates in desert areas far from polluted urban regions. During transport, dust layers can interact with anthropogenic sulfate and soot aerosols from heavily polluted urban areas. Springtime is also the peak season for biomass burning in southeastern Asia. Added to the complex effects of clouds and natural marine aerosols, dust particles reaching the marine environment can have drastically different properties than those from the source. Thus, understanding the unique temporal and spatial variations of Asian aerosols is of special importance in regional-to-global climate issues such as radiative forcing, the hydrological cycle, and primary biological productivity in the mid-Pacific Ocean. During ACE-Asia we have measured continuously aerosol physical/optical/radiative properties, column precipitable water amount, and surface reflectivity over homogeneous areas from surface. The inclusion of flux measurements permits the determination of aerosol radiative flux in addition to measurements of loading and optical depth. At the time of the Terra/MODIS (Moderate Resolution Imaging Spectroradiometer), SeaWiFS (Sea-viewing Wide Field-of-view Sensor), TOMS (Total Ozone Mapping Spectrometer) and other satellite overpasses, these ground-based observations can provide valuable data to compare with satellite retrievals over land. A column satellite-surface perspective of Asian aerosols will be presented

Inter-annual changes of Biomass Burning and Desert Dust and their impact over East Asia

Science.gov (United States)

DONG, X.; Fu, J. S.; Huang, K.

2014-12-01

Impact of mineral dust and biomass burning aerosols on air quality has been well documented in the last few decades, but the knowledge about their interactions with anthropogenic emission and their impacts on regional climate is very limited (IPCC, 2007). While East Asia is greatly affected by dust storms in spring from Taklamakan and Gobi deserts (Huang et al., 2010; Li et al., 2012), it also suffers from significant biomass burning emission from Southeast Asia during the same season. Observations from both surface monitoring and satellite data indicated that mineral dust and biomass burning aerosols may approach to coastal area of East Asia simultaneously, thus have a very unique impact on the local atmospheric environment and regional climate. In this study, we first investigated the inter-annual variations of biomass burning and dust aerosols emission for 5 consecutive years from 2006-2010 to estimate the upper and lower limits and correlation with meteorology conditions, and then evaluate their impacts with a chemical transport system. Our preliminary results indicated that biomass burning has a strong correlation with precipitation over Southeast Asia, which could drive the emission varying from 542 Tg in 2008 to 945 Tg in 2010, according to FLAMBE emission inventory (Reid et al., 2009). Mineral dust also demonstrated a strong dependence on wind filed. These inter-annual/annual variations will also lead to different findings and impacts on air quality in East Asia. Reference: Huang, K., et al. (2010), Mixing of Asian dust with pollution aerosol and the transformation of aerosol components during the dust storm over China in spring 2007, Journal of Geophysical Research-Atmospheres, 115. IPCC (2007), Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, New York. Li, J., et al. (2012), Mixing of Asian mineral dust with anthropogenic pollutants over East Asia: a model case study of a super-duststorm in

Importance of dust storms in the diagenesis of sandstones: a case study, Entrada sandstone in the Ghost Ranch area, New Mexico, USA

Science.gov (United States)

Orhan, Hükmü

1992-04-01

The importance of dust storms on geological processes has only been studied recently. Case-hardening, desert-varnish formation, duricrust development, reddening and cementation of sediments and caliche formation, are some important geological processes related to dust storms. Dust storms can also be a major source for cements in aeolian sandstones. The Jurassic aeolian Entrada Formation in the Ghost Ranch area is composed of quartz with minor amounts of feldspar and rock fragments, and is cemented with smectite as grain coatings and calcite and kaolinite as pore fillings. Smectite shows a crinkly and honeycomb-like morphology which points to an authigenic origin. The absence of smectite as framework grains and the presence of partially dissolved grains, coated with smectite and smectite egg-shells, indicate an external source. Clay and fine silt-size particles are believed to be the major source for cements, smectite and calcite in the Entrada Formation. The common association of kaolinite with altered feldspar, and the absence of kaolinite in spots heavily cemented with calcite, lead to the conclusions that the kaolinite formation postdates carbonates and that framework feldspar grains were the source of kaolinite.

Modeling the Transport and Radiative Forcing of Taklimakan Dust over the Tibetan Plateau: A case study in the summer of 2006

Energy Technology Data Exchange (ETDEWEB)

Chen, Siyu; Huang, J.; Zhao, Chun; Qian, Yun; Leung, Lai-Yung R.; Yang, Ben

2013-01-30

The Weather Research and Forecasting model with chemistry (WRF-Chem) is used to investigate an intense dust storm event during 26 to 30 July 2006 that originated over the Taklimakan Desert (TD) and transported to the northern slope of Tibetan Plateau (TP). The dust storm is initiated by the approach of a strong cold frontal system over the TD. In summer, the meridional transport of TD dust to the TP is favored by the thermal effect of the TP and the weakening of the East Asian westerly winds. During this dust storm, the transport of TD dust over the TP is further enhanced by the passage of the cold front. As a result, TD dust breaks through the planetary boundary layer and extends to the upper troposphere over the northern TP. TD dust flux arrived at the TP with a value of 6.6 Gg/day in this 5 day event but decays quickly during the southward migration over the TP due to dry deposition. The simulations show that TD dust cools the atmosphere near the surface and heats the atmosphere above with a maximum heating rate of 0.11 K day-1 at ~7 km over the TP. The event-averaged net radiative forcings of TD dust over the TP are -3.97, 1.61, and -5.58 Wm-2 at the top of the atmosphere (TOA), in the atmosphere, and at the surface, respectively. The promising performance of WRF-Chem in simulating dust and its radiative forcing provides confidence for use in further investigation of climatic impact of TD dust over the TP.

Remote-sensing-based analysis of landscape change in the desiccated seabed of the Aral Sea--a potential tool for assessing the hazard degree of dust and salt storms.

Science.gov (United States)

Löw, F; Navratil, P; Kotte, K; Schöler, H F; Bubenzer, O

2013-10-01

With the recession of the Aral Sea in Central Asia, once the world's fourth largest lake, a huge new saline desert emerged which is nowadays called the Aralkum. Saline soils in the Aralkum are a major source for dust and salt storms in the region. The aim of this study was to analyze the spatio-temporal land cover change dynamics in the Aralkum and discuss potential implications for the recent and future dust and salt storm activity in the region. MODIS satellite time series were classified from 2000-2008 and change of land cover was quantified. The Aral Sea desiccation accelerated between 2004 and 2008. The area of sandy surfaces and salt soils, which bear the greatest dust and salt storm generation potential increased by more than 36 %. In parts of the Aralkum desalinization of soils was found to take place within 4-8 years. The implication of the ongoing regression of the Aral Sea is that the expansion of saline surfaces will continue. Knowing the spatio-temporal dynamics of both the location and the surface characteristics of the source areas for dust and salt storms allows drawing conclusions about the potential hazard degree of the dust load. The remote-sensing-based land cover assessment presented in this study could be coupled with existing knowledge on the location of source areas for an early estimation of trends in shifting dust composition. Opportunities, limits, and requirements of satellite-based land cover classification and change detection in the Aralkum are discussed.

Long-range atmospheric transport of volatile monocarboxylic acids with Asian dust over a high mountain snow site, central Japan

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T. Mochizuki

2016-11-01

Full Text Available To understand the long-range transport of monocarboxylic acids from the Asian continent to the Japanese islands, we collected snowpack samples from a pit sequence (depth ca. 6 m at the Murodo-Daira snowfield near the summit of Mt. Tateyama, central Japan, in 2009 and 2011. Snow samples (n = 16 were analyzed for normal (C1–C10, branched chain (iC4–iC6, aromatic (benzoic and toluic acid isomers, and hydroxyl (glycolic and lactic monocarboxylic acids, together with inorganic ions and dissolved organic carbon (DOC. Acetic acid (C2 was found to be a dominant species (average 125 ng g−1, followed by formic acid (C1 (85.7 ng g−1 and isopentanoic acid (iC5 (20.0 ng g−1. We found a strong correlation (r =  0.88 between formic plus acetic acids and non-sea-salt Ca2+ that is a proxy of Asian dust. Contributions of total monocarboxylic acids to DOC in 2009 (21.2 ± 11.6 % were higher than that in 2011 (3.75 ± 2.62 %, being consistent with higher intensity of Asian dust in 2009 than in 2011. Formic plus acetic acids also showed a positive correlation (r =  0.90 with benzoic acid that is a tracer of automobile exhaust, indicating that monocarboxylic acids and their precursors are largely emitted from anthropogenic sources in China and/or secondarily produced in the atmosphere by photochemical processing. In addition, the ratio of formic plus acetic acids to nss–Ca2+ (0.27 was significantly higher than those (0.00036–0.0018 obtained for reference dust materials of Chinese loess deposits from the Tengger and Gobi deserts. This result suggests that volatile and semi-volatile organic acids are adsorbed on the alkaline dust particles during long-range atmospheric transport. Entrainment of organic acids by dusts is supported by a good correlation (r = 0.87 between formic plus acetic acids and pH of melt snow samples. Our study suggests that Asian alkaline dusts may be a carrier of volatile monocarboxylic

A Dynamic Enhancement With Background Reduction Algorithm: Overview and Application to Satellite-Based Dust Storm Detection

Science.gov (United States)

Miller, Steven D.; Bankert, Richard L.; Solbrig, Jeremy E.; Forsythe, John M.; Noh, Yoo-Jeong; Grasso, Lewis D.

2017-12-01

This paper describes a Dynamic Enhancement Background Reduction Algorithm (DEBRA) applicable to multispectral satellite imaging radiometers. DEBRA uses ancillary information about the clear-sky background to reduce false detections of atmospheric parameters in complex scenes. Applied here to the detection of lofted dust, DEBRA enlists a surface emissivity database coupled with a climatological database of surface temperature to approximate the clear-sky equivalent signal for selected infrared-based multispectral dust detection tests. This background allows for suppression of false alarms caused by land surface features while retaining some ability to detect dust above those problematic surfaces. The algorithm is applicable to both day and nighttime observations and enables weighted combinations of dust detection tests. The results are provided quantitatively, as a detection confidence factor [0, 1], but are also readily visualized as enhanced imagery. Utilizing the DEBRA confidence factor as a scaling factor in false color red/green/blue imagery enables depiction of the targeted parameter in the context of the local meteorology and topography. In this way, the method holds utility to both automated clients and human analysts alike. Examples of DEBRA performance from notable dust storms and comparisons against other detection methods and independent observations are presented.

Characterisation of bio-aerosols during dust storm period in N-NW India

Science.gov (United States)

Yadav, Sudesh; Chauhan, M. S.; Sharma, Anupam

Bio-investigations for pollen and spores were performed on dry free-fall dust and PM 10 aerosol samples, collected from three different locations separated by a distance of 600 km, situated in dust storm hit region of N-NW India. Presence of pollen of trees namely Prosopis ( Prosopis juliflora and Prosopis cinearia), Acacia, Syzygium, Pinus, Cedrus, Holoptelea and shrubs namely Ziziphus, Ricinus, Ephedra and members of Fabaceae, Oleaceae families was recorded but with varying proportions in the samples of different locations. Poaceae, Chenopodiaceae/Amaranthaceae, Caryophyllaceae, Brassicaceae and Cyperaceae (sedges) were some of the herb pollen identified in the samples. Among the fungal spores Nigrospora was seen in almost all samples. Nigrospora is a well known allergen and causes health problems. The concentration of trees and shrubs increases in the windward direction just as the climate changes from hot arid to semiarid. The higher frequency of grasses (Poaceae) or herbs could either be a result of the presence of these herbs in the sampling area and hence the higher production of pollen/spores or due to the resuspension from the exposed surface by the high-intensity winds. But we cannot ascertain the exact process at this stage. The overall similarity in the pollen and spore assemblage in our dust samples indicates a common connection or source(s) to the dust in this region. Presence of the pollen of the species of Himalayan origin in our entire samples strongly point towards a Himalayan connection, could be direct or indirect, to the bioaerosols and hence dust in N-NW India. In order to understand the transport path and processes involved therein, present study needs further extension with more number of samples and with reference to meteorological parameters.

The potential influence of Asian and African mineral dust on ice, mixed-phase and liquid water clouds

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A. Wiacek

2010-09-01

Full Text Available This modelling study explores the availability of mineral dust particles as ice nuclei for interactions with ice, mixed-phase and liquid water clouds, also tracking the particles' history of cloud-processing. We performed 61 320 one-week forward trajectory calculations originating near the surface of major dust emitting regions in Africa and Asia using high-resolution meteorological analysis fields for the year 2007. Dust-bearing trajectories were assumed to be those coinciding with known dust emission seasons, without explicitly modelling dust emission and deposition processes. We found that dust emissions from Asian deserts lead to a higher potential for interactions with high ice clouds, despite being the climatologically much smaller dust emission source. This is due to Asian regions experiencing significantly more ascent than African regions, with strongest ascent in the Asian Taklimakan desert at ~25%, ~40% and 10% of trajectories ascending to 300 hPa in spring, summer and fall, respectively. The specific humidity at each trajectory's starting point was transported in a Lagrangian manner and relative humidities with respect to water and ice were calculated in 6-h steps downstream, allowing us to estimate the formation of liquid, mixed-phase and ice clouds. Downstream of the investigated dust sources, practically none of the simulated air parcels reached conditions of homogeneous ice nucleation (T≲−40 °C along trajectories that have not experienced water saturation first. By far the largest fraction of cloud forming trajectories entered conditions of mixed-phase clouds, where mineral dust will potentially exert the biggest influence. The majority of trajectories also passed through atmospheric regions supersaturated with respect to ice but subsaturated with respect to water, where so-called "warm ice clouds" (T≳−40 °C theoretically may form prior to supercooled water or mixed-phase clouds. The importance of "warm ice

A simplified Suomi NPP VIIRS dust detection algorithm

Science.gov (United States)

Yang, Yikun; Sun, Lin; Zhu, Jinshan; Wei, Jing; Su, Qinghua; Sun, Wenxiao; Liu, Fangwei; Shu, Meiyan

2017-11-01

Due to the complex characteristics of dust and sparse ground-based monitoring stations, dust monitoring is facing severe challenges, especially in dust storm-prone areas. Aim at constructing a high-precision dust storm detection model, a pixel database, consisted of dusts over a variety of typical feature types such as cloud, vegetation, Gobi and ice/snow, was constructed, and their distributions of reflectance and Brightness Temperatures (BT) were analysed, based on which, a new Simplified Dust Detection Algorithm (SDDA) for the Suomi National Polar-Orbiting Partnership Visible infrared Imaging Radiometer (NPP VIIRS) is proposed. NPP VIIRS images covering the northern China and Mongolian regions, where features serious dust storms, were selected to perform the dust detection experiments. The monitoring results were compared with the true colour composite images, and results showed that most of the dust areas can be accurately detected, except for fragmented thin dusts over bright surfaces. The dust ground-based measurements obtained from the Meteorological Information Comprehensive Analysis and Process System (MICAPS) and the Ozone Monitoring Instrument Aerosol Index (OMI AI) products were selected for comparison purposes. Results showed that the dust monitoring results agreed well in the spatial distribution with OMI AI dust products and the MICAPS ground-measured data with an average high accuracy of 83.10%. The SDDA is relatively robust and can realize automatic monitoring for dust storms.

Radiative Effects of Aerosols Generated from Biomass Burning, Dust Storms, and Forest Fires

Science.gov (United States)

Christopher Sundar A.; Vulcan, Donna V.; Welch, Ronald M.

1996-01-01

Atmospheric aerosol particles, both natural and anthropogenic, are important to the earth's radiative balance. They scatter the incoming solar radiation and modify the shortwave reflective properties of clouds by acting as Cloud Condensation Nuclei (CCN). Although it has been recognized that aerosols exert a net cooling influence on climate (Twomey et al. 1984), this effect has received much less attention than the radiative forcings due to clouds and greenhouse gases. The radiative forcing due to aerosols is comparable in magnitude to current anthropogenic greenhouse gas forcing but opposite in sign (Houghton et al. 1990). Atmospheric aerosol particles generated from biomass burning, dust storms and forest fires are important regional climatic variables. A recent study by Penner et al. (1992) proposed that smoke particles from biomass burning may have a significant impact on the global radiation balance. They estimate that about 114 Tg of smoke is produced per year in the tropics through biomass burning. The direct and indirect effects of smoke aerosol due to biomass burning could add up globally to a cooling effect as large as 2 W/sq m. Ackerman and Chung (1992) used model calculations and the Earth Radiation Budget Experiment (ERBE) data to show that in comparison to clear days, the heavy dust loading over the Saudi Arabian peninsula can change the Top of the Atmosphere (TOA) clear sky shortwave and longwave radiant exitance by 40-90 W/sq m and 5-20 W/sq m, respectively. Large particle concentrations produced from these types of events often are found with optical thicknesses greater than one. These aerosol particles are transported across considerable distances from the source (Fraser et al. 1984). and they could perturb the radiative balance significantly. In this study, the regional radiative effects of aerosols produced from biomass burning, dust storms and forest fires are examined using the Advanced Very High Resolution Radiometer (AVHRR) Local Area

Quantitative estimates of Asian dust input to the western Philippine Sea in the mid-late Quaternary and its potential significance for paleoenvironment

Science.gov (United States)

Xu, Zhaokai; Li, Tiegang; Clift, Peter D.; Lim, Dhongil; Wan, Shiming; Chen, Hongjin; Tang, Zheng; Jiang, Fuqing; Xiong, Zhifang

2015-09-01

We present a new high-resolution multiproxy data set of Sr-Nd isotopes, rare earth element, soluble iron, and total organic carbon data from International Marine Global Change Study Core MD06-3047 located in the western Philippine Sea. We integrate our new data with published clay mineralogy, rare earth element chemistry, thermocline depth, and δ13C differences between benthic and planktonic foraminifera, in order to quantitatively constrain Asian dust input to the basin. We explore the relationship between Philippine Sea and high-latitude Pacific eolian fluxes, as well as its significance for marine productivity and atmospheric CO2 during the mid-late Quaternary. Three different indices indicate that Asian dust contributes between ˜15% and ˜50% to the detrital fraction of the sediments. Eolian dust flux in Core MD06-3047 is similar to that in the polar southern Pacific sediment. Coherent changes for most dust flux maximum/minimum indicate that dust generation in interhemispheric source areas might have a common response to climatic variation over the mid-late Quaternary. Furthermore, we note relatively good coherence between Asian dust input, soluble iron concentration, local marine productivity, and even global atmospheric CO2 concentration over the entire study interval. This suggests that dust-borne iron fertilization of marine phytoplankton might have been a periodic process operating at glacial/interglacial time scales over the past 700 ka. We suggest that strengthening of the biological pump in the Philippine Sea, and elsewhere in the tropical western Pacific during the mid-late Quaternary glacial periods may contribute to the lowering of atmospheric CO2 concentrations during ice ages.

The role of dust storms in total atmospheric particle concentrations at two sites in the western U.S.

Science.gov (United States)

Neff, Jason C.; Reynolds, Richard L.; Munson, Seth M.; Fernandez, Daniel; Belnap, Jayne

2013-01-01

Mineral aerosols are produced during the erosion of soils by wind and are a common source of particles (dust) in arid and semiarid regions. The size of these particles varies widely from less than 2 µm to larger particles that can exceed 50 µm in diameter. In this study, we present two continuous records of total suspended particle (TSP) concentrations at sites in Mesa Verde and Canyonlands National Parks in Colorado and Utah, USA, respectively, and compare those values to measurements of fine and coarse particle concentrations made from nearby samplers. Average annual concentrations of TSP at Mesa Verde were 90 µg m−3 in 2011 and at Canyonlands were 171 µg m−3 in 2009, 113 µg m−3 in 2010, and 134 µg m−3 in 2011. In comparison, annual concentrations of fine (diameter of 2.5 µm and below) and coarse (2.5–10 µm diameter) particles at these sites were below 10 µg m−3 in all years. The high concentrations of TSP appear to be the result of regional dust storms with elevated concentrations of particles greater than 10 µm in diameter. These conditions regularly occur from spring through fall with 2 week mean TSP periodically in excess of 200 µg m−3. Measurement of particles on filters indicates that the median particle size varies between approximately 10 µm in winter and 40 µm during the spring. These persistently elevated concentrations of large particles indicate that regional dust emission as dust storms and events are important determinants of air quality in this region.

Impact of Two Intense Dust Storms on Aerosol Characteristics and Radiative Forcing over Patiala, Northwestern India

Directory of Open Access Journals (Sweden)

Deepti Sharma

2012-01-01

Full Text Available Impact of dust storms on the aerosol characteristics and radiative forcing over Patiala, northwestern India has been studied during April-June of 2010 using satellite observations and ground-based measurements. Six dust events (DE have been identified during the study period with average values of Aqua-MODIS AOD550 and Microtops-II AOD500 over Patiala as 1.00±0.51 and 0.84±0.41, respectively while Aura-OMI AI exhibits high values ranging from 2.01 to 6.74. The Ångström coefficients α380–870 and β range from 0.12 to 0.31 and 0.95 to 1.40, respectively. The measured spectral AODs, the OPAC-derived aerosol properties and the surface albedo obtained from MODIS were used as main inputs in SBDART model for the calculation of aerosol radiative forcing (ARF over Patiala. The ARF at surface (SRF and top of atmosphere (TOA ranges from ∼−50 to −100 Wm−2 and from ∼−10 to −25 Wm−2, respectively during the maximum of dust storms. The radiative forcing efficiency was found to be −66 Wm−2AOD−1 at SRF and −14 Wm−2AOD−1 at TOA. High values of ARF in the atmosphere (ATM, ranging between ∼+40 Wm−2 and +80.0 Wm−2 during the DE days, might have significant effect on the warming of the lower and middle atmosphere and, hence, on climate over northwestern India.

Maintaining the Background Dust Opacity During Northern Hemisphere Summer Mars Using Wind Stress Based Dust Lifting

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Jha, V.; Kahre, M. A.

2017-12-01

The Mars atmosphere has low levels of dust during Northern Hemisphere (NH) spring and summer (the non-dusty season) and increased levels during NH autumn and winter (the dusty season). In the absence of regional or global storms, dust devils and local storms maintain a background minimum dust loading during the non-dusty season. While observational surveys and Global Climate Model (GCM) studies suggest that dust devils are likely to be major contributors to the background haze during NH spring and summer, a complete understanding of the relative contribution of dust devils and local dust storms has not yet been achieved. We present preliminary results from an investigation that focuses on the effects of radiatively active water ice clouds on dust lifting processes during these seasons. Water ice clouds are known to affect atmospheric temperatures directly by absorption and emission of thermal infrared radiation and indirectly through dynamical feedbacks. Our goal is to understand how clouds affect the contribution by local (wind stress) dust storms to the background dust haze during NH spring and summer. The primary tool for this work is the NASA Ames Mars GCM, which contains physical parameterizations for a fully interactive dust cycle. Three simulations that included wind stress dust lifting were executed for a period of 5 Martian years: a case that included no cloud formation, a case that included radiatively inert cloud formation and a case that included radiatively active cloud (RAC) formation. Results show that when radiatively active clouds are included, the clouds in the aphelion cloud belt radiatively heat the atmosphere aloft in the tropics (Figure 1). This heating produces a stronger overturning circulation, which in turn produces an enhanced low-level flow in the Hadley cell return branch. The stronger low-level flow drives higher surface stresses and increased dust lifting in those locations. We examine how realistic these simulated results are by

Time-course monitoring of urban bioaerosol bacterial communities and its use in microbial hazard identification during Asian Dust events in Seoul, Korea

Science.gov (United States)

Park, J.

2015-12-01

The microbial communities transported by Asian dust events have attracted much attention as bioaerosols because the transported airborne microbes may strongly influence the downwind ecosystems and potentially human health in East Asia. Bioaerosol study has received relatively little attention and their characterization and risk assessments remain poorly developed. We used high throughput 16S rRNA gene targeted pyrosequencing and real-time quantitative PCR (qPCR) to monitor airborne bacterial communities and assess their potential risk. We monitored microbial communities in bioaerosol in Seoul between 2011 and 2013 using high volume air samplers. Six samples were collected during Asian dust (AD) events and the other 34 samples were urban air collected during non-Asian dust (non-AD) events. According to the qPCR result, the gene copy numbers of 16S rRNA genes were significantly higher during the AD events (P culture methods. 16S rRNA gene sequences of several pathogens were detected and their relative abundances appeared to have increased with increased concentrations of PM10. About 1% of Bacillus isolates were identified as known pathogenic B. cereus, confirming their presence in Asian dust samples. The qPCR detection of bceT gene, which codes for an enterotoxin in B. cereus group, was significantly increased in the AD dust samples over the non-AD samples. The following MLST assessment and virulence test of cultivated Bacillus isolates showed that B. cereus, B. licheniformis and B. mycoides were identified as pathogenic bacteria, and these pathogenic bacteria were usually more abundant during AD events. To assess the possible associations of identified pathogens on the hospital stroke admissions of residents in Seoul, we identified sixteen bioaerosol episodes using Poisson regression and calculated relative risk. The findings are useful in building a database for bacterial pathogens in AD events.

Effects of Asian sand dust particles on the respiratory and immune system.

OpenAIRE

Honda, Akiko; Matsuda, Yugo; Murayama, Rumiko; Tsuji, Kenshi; Nishikawa, Masataka; Koike, Eiko; Yoshida, Seiichi; Ichinose, Takamichi; Takano, Hirohisa

2013-01-01

Epidemiologic studies have reported that Asian sand dust (ASD) particles can affect respiratory health; however, the mechanisms remain unclear. We investigated the effects of ASD on airway epithelial cells and immune cells, and their contributing factors to the effects. Human airway epithelial cells were exposed to ASD collected on 1-3 May (ASD1) and on 12-14 May (ASD2) 2011 in Japan and heat-treated ASD1 for excluding heat-sensitive substances (H-ASD) at a concentration of 0, 3, 30 or 90 µg ...

Airborne Dust, "The Good Guy or the Bad Guy": How Much do We Know?

Science.gov (United States)

Tsay, Si-Chee

2010-01-01

Processes in generating, transporting, and dissipating the airborne dust particles are global phenomena -African dust regularly reaching the Alps; Asian dust seasonally crossing the Pacific into North America, and ultimately the Atlantic into Europe. One of the vital biogeochemical roles dust storms play in Earth's ecosystem is routinely mobilizing mineral dust, as a source of iron, from deserts into oceans for fertilizing the growth of phytoplankton -the basis of the oceanic food chain. Similarly, these dust-laden airs also supply crucial nutrients for the soil of tropical rain forests, the so-called womb of life that hosts 50-90% of the species on Earth. With massive amounts of dust lifted from desert regions and injected into the atmosphere, however, these dust storms often affect daily activities in dramatic ways: pushing grit through windows and doors, forcing people to stay indoors, causing breathing problems, reducing visibility and delaying flights, and by and large creating chaos. Thus, both increasing and decreasing concentrations of doses result in harmful biological effects; so do the airborne dust particles to our Living Earth. Since 1997 NASA has been successfully launching a series of satellites - the Earth Observing System - to intensively study, and gain a better understanding of, the Earth as an integrated system. Through participation in many satellite remote-sensing/retrieval and validation projects over the years, we have gradually developed and refined the SMART (Surface-sensing Measurements for Atmospheric Radiative Transfer) and COMMIT (Chemical, Optical & Microphysical Measurements of In-situ Troposphere) mobile observatories, a suite of surface remote sensing and in-situ instruments that proved to be vital in providing high temporal measurements, which complement the satellite observations. In this talk, we will present SMART-COMMIT which has played key roles, serving as network or supersite, in major international research projects such

Orbital time scale records of Asian eolian dust from the Sea of Japan since the early Pliocene

Science.gov (United States)

Zhang, Wenfang; De Vleeschouwer, David; Shen, Ji; Zhang, Zeke; Zeng, Lin

2018-05-01

A high-resolution potassium content record of sediments from Integrated Ocean Drilling Program (IODP) Site U1422 drilled in the northern Sea of Japan was employed to yield an astronomical timescale for this ∼205 m thick sedimentary archive. The K content was quantified using the natural gamma radiation (NGR) data routinely measured on DV JOIDES Resolution. The U1422 K (wt.%) series shows an increasing trend with time, which parallels the growth of North Hemisphere ice sheets since ∼4 Ma, as revealed by the global benthic foraminifer's oxygen isotope stack (LR04). We propose that K content variations reflect changes in the relative contributions of Asian eolian dust and volcanic weathering products, in response to changes in global ice volume. Using the shipboard age model, constrained by palaeomagnetism and nanofossils datums, we tuned the U1422 K content variations to the LR04 stack. Our tuned age model for site U1422 goes back to 3.9 Ma. The studied record indicates that Asian dust generation is enhanced during periods of global cooling. The synchronous variations between the U1422 K record and the LR04 stack also suggest that global cooling played a dominant role in promoting the central Asian aridification since ∼3.9 Ma, while the uplift of Tibetan Plateau plays a secondary role, considering many disagreements still exists between the timing and amplitude of the Qinghai-Tibetan uplift and the evolution of central Asian aridity since the early Pliocene.

Excess 228Th in the airborne dust: An indicator of continental dust from the East Asian deserts

International Nuclear Information System (INIS)

Hirose, K.; Sugimura, Y.

1984-01-01

Thorium isotopes in the airborne dust collected at Tsukuba Science City in Japan from January 1981 to December 1982 show clear seasonal variations. Especially 228 Th in the airborne particles have a typical maximum concentration between February and April, which is about an order of magnitude higher than during the remainder of the year. According to the result of size distribution of thorium isotope-bearing particles in the air, about 53% of 228 Th is associated with the particles less than 1.6 μm aerodynamic diameter. These results reveal that 228 Th in the airborne particles is present in fine soily matters originating from the East Asian deserts. (orig.)

Temporal and spatial variation in radioactivity deposition in Japan-influence of the Asian dust-Kosa

International Nuclear Information System (INIS)

Igarashi, Yasuhito; Aoyama, Michio; Hirose, Katsumi; Shinoda, Yoshihiro

2007-01-01

The possible effect of Asian dust-Kosa in radioactivity deposition, recorded during the recent years, is addressed. The Kosa events were remarkable during 2000 to 2002 in the Far East region, however no significant change was admitted in the MRI radioactivity deposition time series for 90 Sr and 137 Cs. Therefore, we looked at the nationwide distribution and seasonal trends in 90 Sr and 137 Cs depositions by using the data from the Environmental Radioactivity and Radiation Database available on the web. It was found that 137 Cs deposition was larger in northern Japan along the Japan Sea side during spring. The 137 Cs/ 90 Sr activity ratio as well as the 137 Cs specific activity tended to be larger at the high 137 Cs deposition sites. The influence of the Kosa during 2000 to 2002 had larger in northern Japan/Sea of Japan side and the source of the Kosa may be different from the conventional type of the Kosa. The high 137 Cs/ 90 Sr activity ratio and the high 137 Cs specific activity suggest the source area had higher precipitation rate (higher fallout), where the fractionation between the 137 Cs and 90 Sr proceeded. Such area may become new source area for the aeolian dust due possibly to the recent global climate change. This accords with the literature on the source statistics of the Asian dust during the 1990s and the early 2000s. (author)

Isotopic evidences for provenances of east asian dust

International Nuclear Information System (INIS)

Yang Jiedong; Chen Jun; Li Gaojun; Ji Junfeng; Rao Wenbo

2007-01-01

, but the provenances of dust storm in April, 2006 mainly is Region C, i.e. the Mu Us Desert and Hobq Desert. (authors)

Atmosphere aerosol/dust composition over central Asia and western Siberia derived from snow/ice core records and calibrated with NASA remote sensing data

Science.gov (United States)

Aizen, V. B.; Aizen, E. M.; Joswiak, D. R.; Surazakov, A. B.; Takeuchi, N.

2007-12-01

The vast arid and semi-arid regions of central Asia, Mongolia, and Northern China are the world's second largest source of atmospheric mineral dust. In recent years, severe dust storms in Asia have intensified in frequency, duration, and areal coverage. However, limited spatial and temporal extent of aerosol measurements precludes definitive statements to be made regarding relationship between the Asian aerosol generation and climate. It has been well known that glaciers are the natural archives of environmental records related to past climate and aerosol generation. In our research, we utilized central Asian and western Siberia shallow ice-core records recovered from Altai, Tien Shan and Pamir mountain glaciers. Despite the fact that ice-core data may extend climate/aerosol records back in time, their sparse coverage is inadequate to document aerosol spatial distribution. The NASA products from Aura, Terra and Aqua satellite missions address this gap identifying aerosol sources, transport pathways, and area of deposition. The main objective of our research is to evaluate an affect of climate variability on dynamics of Asian aerosol loading to atmosphere and changes in aerosol transport pathways. Dust particle, major and rare earth element analysis from dust aerosols deposited and accumulated in Altai, Tien Shan and Pamir glaciers suggests that loess from Tajikistan, Afghanistan and north-western China are main sources of aerosol loading into the upper troposphere over the central Asia and western Siberia. At the same time, the soluble ionic component of the ice-cores, related to aerosol generated from evaporate deposits, demonstrated both anthropogenic and natural impacts on atmospheric chemistry over these regions. Large perturbations of Ca2+ derived from CaCO3- rich dust transported from Goby Desert to Altai and Tien Shan. Origin and pathway of the ice-core aerosol depositions for the last 10-years were identified through calibrating ice-core records with dust

Transpacific Transport of Dust to North American High-Elevation Sites: Integrated Dataset and Model Outputs

Science.gov (United States)

Kassianov, E.; Pekour, M. S.; Flynn, C. J.; Berg, L. K.; Beranek, J.; Zelenyuk, A.; Zhao, C.; Leung, L. R.; Ma, P. L.; Riihimaki, L.; Fast, J. D.; Barnard, J.; Hallar, G. G.; McCubbin, I.; Eloranta, E. W.; McComiskey, A. C.; Rasch, P. J.

2017-12-01

Understanding the effects of dust on the regional and global climate requires detailed information on particle size distributions and their changes with distance from the source. Awareness is now growing about the tendency of the dust coarse mode with moderate ( 3.5 µm) volume median diameter (VMD) to be rather insensitive to complex removal processes associated with long-range transport of dust from the main sources. Our study, with a focus on the transpacific transport of dust, demonstrates that the impact of coarse mode aerosol (VMD 3µm) is well defined at the high-elevation mountain-top Storm Peak Laboratory (SPL, about 3.2 km MSL) and nearby Atmospheric Radiation Measurement (ARM) Climate Research Facility Mobile Facility (AMF) during March 2011. Significant amounts of coarse mode aerosol are also found at the nearest Aerosol Robotic Network (AERONET) site. Outputs from the high-resolution Weather Research and Forecasting (WRF) Model coupled with chemistry (WRF-Chem) show that the major dust event is likely associated with transpacific transport of Asian and African plumes. Satellite data, including the Moderate Resolution Imaging Spectroradiometer (MODIS) and Multiangle Imaging SpectroRadiometer (MISR) aerosol optical depth (AOD) and plume height from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) lidar data provide the observational support of the WRF-Chem simulations. Our study complements previous findings by indicating that the quasi-static nature of the coarse mode appears to be a reasonable approximation for Asian and African dust despite expected frequent orographic precipitation over mountainous regions in the western United States.

The global distribution of mineral dust

International Nuclear Information System (INIS)

Tegen, I; Schepanski, K

2009-01-01

Dust aerosol particles produced by wind erosion in arid and semi arid regions affect climate and air quality, but the magnitude of these effects is largely unquantified. The major dust source regions include the Sahara, the Arabian and Asian deserts; global annual dust emissions are currently estimated to range between 1000 and 3000 Mt/yr. Dust aerosol can be transported over long distances of thousands of kilometers, e.g. from source regions in the Saharan desert over the North Atlantic, or from the Asian deserts towards the Pacific Ocean. The atmospheric dust load varies considerably on different timescales. While dust aerosol distribution and dust effects are important on global scales, they strongly depend on dust emissions that are controlled on small spatial and temporal scales.

Long-term profiling of mineral dust and pollution aerosol with multiwavelength polarization Raman lidar at the Central Asian site of Dushanbe, Tajikistan: case studies

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J. Hofer

2017-12-01

Full Text Available For the first time, continuous vertically resolved aerosol measurements were performed by lidar in Tajikistan, Central Asia. Observations with the multiwavelength polarization Raman lidar PollyXT were conducted during CADEX (Central Asian Dust EXperiment in Dushanbe, Tajikistan, from March 2015 to August 2016. Co-located with the lidar, a sun photometer was also operated. The goal of CADEX is to provide an unprecedented data set on vertically resolved aerosol optical properties in Central Asia, an area highly affected by climate change but largely missing vertically resolved aerosol measurements. During the 18-month measurement campaign, mineral dust was detected frequently from ground to the cirrus level height. In this study, an overview of the measurement period is given and four typical but different example measurement cases are discussed in detail. Three of them are dust cases and one is a contrasting pollution aerosol case. Vertical profiles of the measured optical properties and the calculated dust and non-dust mass concentrations are presented. Dust source regions were identified by means of backward trajectory analyses. A lofted layer of Middle Eastern dust with an aerosol optical thickness (AOT of 0.4 and an extinction-related Ångström exponent of 0.41 was measured. In comparison, two near-ground dust cases have Central Asian sources. One is an extreme dust event with an AOT of 1.5 and Ångström exponent of 0.12 and the other one is a most extreme dust event with an AOT of above 4 (measured by sun photometer and an Ångström exponent of −0.08. The observed lidar ratios (and particle linear depolarization ratios in the presented dust cases range from 40.3 to 46.9 sr (and 0.18–0.29 at 355 nm and from 35.7 to 42.9 sr (0.31–0.35 at 532 nm wavelength. The particle linear depolarization ratios indicate almost unpolluted dust in the case of a lofted dust layer and pure dust in the near-ground dust cases. The lidar ratio

Large Contribution of Coarse Mode to Aerosol Microphysical and Optical Properties: Evidence from Ground-Based Observations of a Transpacific Dust Outbreak at a High-Elevation North American Site

Energy Technology Data Exchange (ETDEWEB)

Kassianov, E. [Pacific Northwest National Laboratory, Richland, Washington; Pekour, M. [Pacific Northwest National Laboratory, Richland, Washington; Flynn, C. [Pacific Northwest National Laboratory, Richland, Washington; Berg, L. K. [Pacific Northwest National Laboratory, Richland, Washington; Beranek, J. [Pacific Northwest National Laboratory, Richland, Washington; Zelenyuk, A. [Pacific Northwest National Laboratory, Richland, Washington; Zhao, C. [Pacific Northwest National Laboratory, Richland, Washington; Leung, L. R. [Pacific Northwest National Laboratory, Richland, Washington; Ma, P. L. [Pacific Northwest National Laboratory, Richland, Washington; Riihimaki, L. [Pacific Northwest National Laboratory, Richland, Washington; Fast, J. D. [Pacific Northwest National Laboratory, Richland, Washington; Barnard, J. [University of Nevada, Reno, Nevada; Hallar, A. G. [Storm Peak Laboratory, Desert Research Institute, Steamboat Springs, Colorado; McCubbin, I. B. [Storm Peak Laboratory, Desert Research Institute, Steamboat Springs, Colorado; Eloranta, E. W. [University of Wisconsin–Madison, Madison, Wisconsin; McComiskey, A. [National Oceanic and Atmospheric Administration, Boulder, Colorado; Rasch, P. J. [Pacific Northwest National Laboratory, Richland, Washington

2017-05-01

Our work is motivated by previous studies of the long-range trans-Atlantic transport of Saharan dust and the observed quasi-static nature of coarse mode aerosol with a volume median diameter (VMD) of approximately 3.5 µm. We examine coarse mode contributions from the trans-Pacific transport of Asian dust to North American aerosol microphysical and optical properties using a dataset collected at the high-elevation, mountain-top Storm Peak Laboratory (SPL, 3.22 km above sea level [ASL]) and the nearby Atmospheric Radiation Measurement (ARM) Mobile Facility (AMF, 2.76 km ASL). Data collected during the SPL Cloud Property Validation Experiment (STORMVEX, March 2011) are complemented by quasi-global high-resolution model simulations coupled with aerosol chemistry. We identify dust event associated mostly with Asian plume (about 70% of dust mass) where the coarse mode with moderate (~4 µm) VMD is distinct and contributes substantially to aerosol microphysical (up to 70% for total volume) and optical (up to 45% for total scattering and aerosol optical depth) properties. Our results, when compared with previous Saharan dust studies, suggest a fairly invariant behavior of coarse mode dust aerosols. If confirmed in additional studies, this invariant behavior may simplify considerably model parameterizations for complex and size-dependent processes associated with dust transport and removal.

Influence of Asian dust particles on immune adjuvant effects and airway inflammation in asthma model mice.

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Jun Kurai

Full Text Available An Asian dust storm (ADS contains airborne particles that affect conditions such as asthma, but the mechanism of exacerbation is unclear. The objective of this study was to compare immune adjuvant effects and airway inflammation induced by airborne particles collected on ADS days and the original ADS soil (CJ-1 soil in asthma model mice.Airborne particles were collected on ADS days in western Japan. NC/Nga mice were co-sensitized by intranasal instillation with ADS airborne particles and/or Dermatophagoides farinae (Df, and with CJ-1 soil and/or Df for 5 consecutive days. Df-sensitized mice were stimulated with Df challenge intranasally at 7 days after the last Df sensitization. At 24 hours after challenge, serum allergen specific antibody, differential leukocyte count and inflammatory cytokines in bronchoalveolar lavage fluid (BALF were measured, and airway inflammation was examined histopathologically.Co-sensitization with ADS airborne particles and Df increased the neutrophil and eosinophil counts in BALF. Augmentation of airway inflammation was also observed in peribronchiolar and perivascular lung areas. Df-specific serum IgE was significantly elevated by ADS airborne particles, but not by CJ-1 soil. Levels of interleukin (IL-5, IL-13, IL-6, and macrophage inflammatory protein-2 were higher in BALF in mice treated with ADS airborne particles.These results suggest that substances attached to ADS airborne particles that are not in the original ADS soil may play important roles in immune adjuvant effects and airway inflammation.

Responses of heterotrophic bacteria abundance and activity to Asian dust enrichment in the low nutrients and low chlorophyll (LNLC) region of the Northwestern Pacific Ocean

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Shi, Dongwan; Li, Kuiran; Tian, Yanzhao; Zhang, Xiaohao; Bai, Jie

2017-05-01

Bacteria, as an essential part of microbial food web, play a significant role in the marine ecosystem. Dust deposits into the surface ocean carrying with vital nutrient such as Inorganic nitrogen and phosphorus etc., which has an important influence on the life activities of heterotrophic bacteria. The microcosm experiments with Asian dust deposition was carried out on board in the station K3 (26.18°N, 136.73°E) in April 2015, aiming to estimate the impact of dust deposition on the oligotrophic Northwestern pacific Sea, the main goal of the present paper was to assess how dust deposition events affect the abundance and activity of heterotrophic bacteria in low nutrient and low chlorophyll (LNLC) sea area. Station K3 located in the central northwestern Pacific Ocean, which has the characteristic of low nutrient and low chlorophyll. The study shows that there was an N-P co-limitation in station K3, and the deposition of Asian dust can increase the abundance, and promote the activity of heterotrophic bacteria in the station K3.

Aerosol deposition and suspension during a Texas dust storm

International Nuclear Information System (INIS)

Porch, W.M.; Lovill, J.E.

1976-03-01

It is important to understand deposition and suspension of aerosol by wind as separate phenomena. This is especially true for the case of a contaminated area of land, contributing toxic aerosol. Once the toxic particulates have left the contaminated area, they can only deposit, even though new non-toxic particulates are being suspended all around them. A fortunate meteorological situation and a site with fast response aerosol and wind instrumentation, allowed us to analyze deposition and suspension, as separate phenomena on the same data record during a Texas dust storm. The major results of this analysis can be summarized as follows: The size distribution of the soil particulates and the geometrical orientation of plowed furrows to the wind are important to the threshold velocity, beyond which particles will be suspended from bare soil. Thresholds this year for clay soil were almost double that for the previous year for sand soil; the relationship between aerosol flux and wind speed above threshold was less well defined than the sandy soil data. The relationship does seem to involve a lower exponent than the sandy soil data, which showed a flux that varied as about the sixth power of the wind speed

Characterization of individual ice residual particles by the single droplet freezing method: a case study in the Asian dust outflow region

Science.gov (United States)

Iwata, Ayumi; Matsuki, Atsushi

2018-02-01

In order to better characterize ice nucleating (IN) aerosol particles in the atmosphere, we investigated the chemical composition, mixing state, and morphology of atmospheric aerosols that nucleate ice under conditions relevant for mixed-phase clouds. Five standard mineral dust samples (quartz, K-feldspar, Na-feldspar, Arizona test dust, and Asian dust source particles) were compared with actual aerosol particles collected from the west coast of Japan (the city of Kanazawa) during Asian dust events in February and April 2016. Following droplet activation by particles deposited on a hydrophobic Si (silicon) wafer substrate under supersaturated air, individual IN particles were located using an optical microscope by gradually cooling the temperature to -30 °C. For the aerosol samples, both the IN active particles and non-active particles were analyzed individually by atomic force microscopy (AFM), micro-Raman spectroscopy, and scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX). Heterogeneous ice nucleation in all standard mineral dust samples tested in this study was observed at consistently higher temperatures (e.g., -22.2 to -24.2 °C with K-feldspar) than the homogeneous freezing temperature (-36.5 °C). Meanwhile, most of the IN active atmospheric particles formed ice below -28 °C, i.e., at lower temperatures than the standard mineral dust samples of pure components. The most abundant IN active particles above -30 °C were predominantly irregular solid particles that showed clay mineral characteristics (or mixtures of several mineral components). Other than clay, Ca-rich particles internally mixed with other components, such as sulfate, were also regarded as IN active particle types. Moreover, sea salt particles were predominantly found in the non-active fraction, and internal mixing with sea salt clearly acted as a significant inhibiting agent for the ice nucleation activity of mineral dust particles. Also, relatively

Difference in the wind speeds required for initiation versus continuation of sand transport on mars: implications for dunes and dust storms.

Science.gov (United States)

Kok, Jasper F

2010-02-19

Much of the surface of Mars is covered by dunes, ripples, and other features formed by the blowing of sand by wind, known as saltation. In addition, saltation loads the atmosphere with dust aerosols, which dominate the Martian climate. We show here that saltation can be maintained on Mars by wind speeds an order of magnitude less than required to initiate it. We further show that this hysteresis effect causes saltation to occur for much lower wind speeds than previously thought. These findings have important implications for the formation of dust storms, sand dunes, and ripples on Mars.

Promotion Effect of Asian Dust on Phytoplankton Growth and Potential Dissolved Organic Phosphorus Utilization in the South China Sea

Science.gov (United States)

Chu, Qiang; Liu, Ying; Shi, Jie; Zhang, Chao; Gong, Xiang; Yao, Xiaohong; Guo, Xinyu; Gao, Huiwang

2018-03-01

Dust deposition is an important nutrient source to the South China Sea (SCS), but few in situ experiments were conducted on phytoplankton response to the deposition. We conducted onboard incubation experiments at three stations near Luzon Strait in the SCS, with addition of multiple dissolved inorganic nutrients, Asian dust, and rainwater. From our results, nitrogen and phosphorus were both urgently needed for phytoplankton growth in the SCS, indicated by the evident Chl a response to the addition of nitrogen and phosphorus together. Almost no evident response was observed by adding phosphorus or iron alone to incubation waters, although a delayed response of Chl a in mass concentration was observed by adding nitrogen alone. The latter implied a possible utilization of dissolved organic phosphorus because of insufficient dissolved inorganic phosphorus in incubation waters. Under such nutrient condition, Asian dust showed an apparent promotion effect on phytoplankton growth by providing sufficient amounts of nitrogen but low phosphorus. Meanwhile, it was found that large sized (> 5 μm) phytoplankton community showed different responses to dust addition at different stations. At stations A3 and A6, Chaetoceros spp. became the dominant species during the bloom period, while at station WG2, Nitzschia spp. became dominant. In combination with different initial nutrients and Chl a levels at the three stations, the different phytoplankton community evolution implied the response difference to external inputs between oligotrophic (stations A3 and A6) and ultraoligotrophic (station WG2) conditions in the SCS.

Viking orbiter imaging observations of dust in the Martian atmosphere

International Nuclear Information System (INIS)

Briggs, G.A.; Baum, W.A.; Barnes, J.

1979-01-01

More than 20 local Martian dust clouds and two global dust storms were observed with the Viking orbiter camera. Sixteen of the local clouds were imaged in two colors or were observed with other instruments confirming their identification as dust clouds. These Viking results are compared with earth-based observations of Martian dust storms and with Mariner 9 data. Most of the dust activity seen by Viking occurred during southern hemisphere spring and early summer, when Mars was near perihelion and isolation was near maximum. About half the local clouds occurred near the edge of the southern polar cap, where winds are presumably enhanced by a strong regional temperature gradient. The other half occurred mainly in the southern hemisphere near regions where circulation models incorporating topography predict positive vertical velocities. Although dust clouds observed from earth show a similar partial correlation with models, some ambiguity exists concerning interpretation of regions near Hellespontus that have spawned the most spectacular Martian dust storms on record

The impact of the winter North Atlantic Oscillation on the frequency of spring dust storms over Tarim Basin in northwest China in the past half-century

International Nuclear Information System (INIS)

Zhao Yong; Huang Anning; Zhou Yang; Huang Ying; Zhu Xinsheng

2013-01-01

The relationship between the frequency of spring dust storms over Tarim Basin in northwest China and the winter North Atlantic Oscillation (NAO) is investigated by using the observed dust storm frequency (DSF) and the 10 m wind velocity at 36 stations in Tarim Basin and the National Centers for Environment Prediction/National Center for Atmospheric Research reanalysis data for the period 1961–2007. The spring DSF (winter NAO) index shows a clear decreasing (increasing) linear trend over 1961–2007. The winter NAO correlates well with the subsequent spring DSF over Tarim Basin on both interannual and interdecadal time scales and its interannual to interdecadal variation plays an important role in the spring DSF. Two possible physical mechanisms are identified. One is related to the large scale anomalous circulations in spring in the middle to high troposphere modulated by the winter NAO, providing the background of dynamical conditions for the dust storm occurrences. The other is related to the shifts in the local horizontal sea level pressure (SLP) gradients and 10 m wind speed, corresponding to changes in the large scale circulations in spring. The decrease in the local 10 m wind speed due to the reduced horizontal SLP gradients over Tarim Basin during the strong winter NAO years contributes to the decline of the DSF in the subsequent spring. (letter)

Lorentz-Shaped Comet Dust Trail Cross Section from New Hybrid Visual and Video Meteor Counting Technique - Implications for Future Leonid Storm Encounters

Science.gov (United States)

Jenniskens, Peter; Crawford, Chris; Butow, Steven J.; Nugent, David; Koop, Mike; Holman, David; Houston, Jane; Jobse, Klaas; Kronk, Gary

2000-01-01

A new hybrid technique of visual and video meteor observations was developed to provide high precision near real-time flux measurements for satellite operators from airborne platforms. A total of 33,000 Leonids. recorded on video during the 1999 Leonid storm, were watched by a team of visual observers using a video head display and an automatic counting tool. The counts reveal that the activity profile of the Leonid storm is a Lorentz profile. By assuming a radial profile for the dust trail that is also a Lorentzian, we make predictions for future encounters. If that assumption is correct, we passed 0.0003 AU deeper into the 1899 trailet than expected during the storm of 1999 and future encounters with the 1866 trailet will be less intense than. predicted elsewhere.

Role of Chinese wind-blown dust in enhancing environmental pollution in Metropolitan Seoul

Energy Technology Data Exchange (ETDEWEB)

Kim, Wonnyon [Department of Earth and Environmental Sciences, Korea University, Seoul 136-713 (Korea, Republic of); Doh, Seong-Jae [Department of Earth and Environmental Sciences, Korea University, Seoul 136-713 (Korea, Republic of)], E-mail: sjdoh@korea.ac.kr; Yu, Yongjae; Lee, Meehye [Department of Earth and Environmental Sciences, Korea University, Seoul 136-713 (Korea, Republic of)

2008-05-15

A suite of rock magnetic experiments and intensive microscopic observations were carried out on Asian dust deposits in Seoul, Korea, collected on 19 and 23 March 2002, 9 April 2002 and 12 April 2003. Desert-sand and loess from the dust source regions in China were also analyzed as a comparison. Asian dust showed a higher magnetic concentration than the source region samples, indicating a significant influx of magnetic particles into Asian dust had occurred during its transportation. Electron microscopy identified carbon-bearing iron-oxides as the added material. These iron-oxides were likely to have been produced by anthropogenic pollution (fossil fuel combustion) while the wind-blown dusts passing across the industrial areas of eastern China and western Korea. Such wind-paths were confirmed by a simulation of the air-mass trajectories. The magnetic technique appears to be useful for determining the anthropogenic pollution of Asian dust. - Magnetic quantification of anthropogenic pollution of Asian dust.

Role of Chinese wind-blown dust in enhancing environmental pollution in Metropolitan Seoul

International Nuclear Information System (INIS)

Kim, Wonnyon; Doh, Seong-Jae; Yu, Yongjae; Lee, Meehye

2008-01-01

A suite of rock magnetic experiments and intensive microscopic observations were carried out on Asian dust deposits in Seoul, Korea, collected on 19 and 23 March 2002, 9 April 2002 and 12 April 2003. Desert-sand and loess from the dust source regions in China were also analyzed as a comparison. Asian dust showed a higher magnetic concentration than the source region samples, indicating a significant influx of magnetic particles into Asian dust had occurred during its transportation. Electron microscopy identified carbon-bearing iron-oxides as the added material. These iron-oxides were likely to have been produced by anthropogenic pollution (fossil fuel combustion) while the wind-blown dusts passing across the industrial areas of eastern China and western Korea. Such wind-paths were confirmed by a simulation of the air-mass trajectories. The magnetic technique appears to be useful for determining the anthropogenic pollution of Asian dust. - Magnetic quantification of anthropogenic pollution of Asian dust

Evidence for Asian dust effects from aerosol plume measurements during INTEX-B 2006 near Whistler, BC

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W. R. Leaitch

2009-06-01

Full Text Available Several cases of aerosol plumes resulting from trans-Pacific transport were observed between 2 km and 5.3 km at Whistler, BC from 22 April 2006 to 15 May 2006. The fine particle (<1 μm chemical composition of most of the plumes was dominated by sulphate that ranged from 1–5 μg m⁻³ as measured with a Quadrapole Aerosol Mass Spectrometer (Q-AMS. Coarse particles (>1 μm were enhanced in all sulphate plumes. Fine particle organic mass concentrations were relatively low in most plumes and were nominally anti-correlated with the increases in the number concentrations of coarse particles. The ion chemistry of coarse particles sampled at Whistler Peak was dominated by calcium, sodium, nitrate, sulphate and formate. Scanning transmission X-ray microscopy of coarse particles sampled from the NCAR C-130 aircraft relatively close to Whistler indicated carbonate, potassium and organic functional groups, in particular the carboxyl group. Asian plumes reaching Whistler, BC during the INTEX-B study were not only significantly reduced of fine particle organic material, but organic compounds were attached to coarse particles in significant quantities. Suspension of dust with deposited organic material and scavenging of organic materials by dust near anthropogenic sources are suggested, and if any secondary organic aerosol (SOA was formed during transport from Asian source regions across the Pacific it was principally associated with the coarse particles. An average of profiles indicates that trans-Pacific transport between 2 and 5 km during this period increased ozone by about 10 ppbv and fine particle sulphate by 0.2–0.5 μg m⁻³. The mean sizes of the fine particles in the sulphate plumes were larger when dust particles were present and smaller when the fine particle organic mass concentration was larger and dust was absent. The coarse particles of dust act to accumulate sulphate, nitrate and organic material in larger particles

Density currents as a desert dust mobilization mechanism

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S. Solomos

2012-11-01

Full Text Available The formation and propagation of density currents are well studied processes in fluid dynamics with many applications in other science fields. In the atmosphere, density currents are usually meso-β/γ phenomena and are often associated with storm downdrafts. These storms are responsible for the formation of severe dust episodes (haboobs over desert areas. In the present study, the formation of a convective cool pool and the associated dust mobilization are examined for a representative event over the western part of Sahara desert. The physical processes involved in the mobilization of dust are described with the use of the integrated atmospheric-air quality RAMS/ICLAMS model. Dust is effectively produced due to the development of near surface vortices and increased turbulent mixing along the frontal line. Increased dust emissions and recirculation of the elevated particles inside the head of the density current result in the formation of a moving "dust wall". Transport of the dust particles in higher layers – outside of the density current – occurs mainly in three ways: (1 Uplifting of preexisting dust over the frontal line with the aid of the strong updraft (2 Entrainment at the upper part of the density current head due to turbulent mixing (3 Vertical mixing after the dilution of the system. The role of the dust in the associated convective cloud system was found to be limited. Proper representation of convective processes and dust mobilization requires the use of high resolution (cloud resolving model configuration and online parameterization of dust production. Haboob-type dust storms are effective dust sources and should be treated accordingly in dust modeling applications.

Characterization of individual ice residual particles by the single droplet freezing method: a case study in the Asian dust outflow region

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A. Iwata

2018-02-01

Full Text Available In order to better characterize ice nucleating (IN aerosol particles in the atmosphere, we investigated the chemical composition, mixing state, and morphology of atmospheric aerosols that nucleate ice under conditions relevant for mixed-phase clouds. Five standard mineral dust samples (quartz, K-feldspar, Na-feldspar, Arizona test dust, and Asian dust source particles were compared with actual aerosol particles collected from the west coast of Japan (the city of Kanazawa during Asian dust events in February and April 2016. Following droplet activation by particles deposited on a hydrophobic Si (silicon wafer substrate under supersaturated air, individual IN particles were located using an optical microscope by gradually cooling the temperature to −30 °C. For the aerosol samples, both the IN active particles and non-active particles were analyzed individually by atomic force microscopy (AFM, micro-Raman spectroscopy, and scanning electron microscopy (SEM coupled with energy dispersive X-ray spectroscopy (EDX. Heterogeneous ice nucleation in all standard mineral dust samples tested in this study was observed at consistently higher temperatures (e.g., −22.2 to −24.2 °C with K-feldspar than the homogeneous freezing temperature (−36.5 °C. Meanwhile, most of the IN active atmospheric particles formed ice below −28 °C, i.e., at lower temperatures than the standard mineral dust samples of pure components. The most abundant IN active particles above −30 °C were predominantly irregular solid particles that showed clay mineral characteristics (or mixtures of several mineral components. Other than clay, Ca-rich particles internally mixed with other components, such as sulfate, were also regarded as IN active particle types. Moreover, sea salt particles were predominantly found in the non-active fraction, and internal mixing with sea salt clearly acted as a significant inhibiting agent for the ice nucleation activity of mineral

Characterization of east Asian dust outbreaks in the spring of 2001 using ground-based and satellite data

Science.gov (United States)

Darmenova, Kremena; Sokolik, Irina N.; Darmenov, Anton

2005-01-01

This study presents a detailed examination of east Asian dust events during March-April of 2001, by combining satellite multisensor observation (Total Ozone Mapping Spectrometer (TOMS), Moderate-Resolution Imaging Spectroradiometer (MODIS), and Sea-Viewing Wide Field-of-View Sensor (SeaWiFS)) meteorological data from weather stations in China and Mongolia and the Pennsylania State University/National Center for Atmospheric Research Mesoscale Modeling System (MM5) driven by the National Centers for Environmental Prediction Reanalysis data. The main goal is to determine the extent to which the routine surface meteorological observations (including visibility) and satellite data can be used to characterize the spatiotemporal distribution of dust plumes at a range of scales. We also examine the potential of meteorological time series for constraining the dust emission schemes used in aerosol transport models. Thirty-five dust events were identified in the source region during March and April of 2001 and characterized on a case-by-case basis. The midrange transport routes were reconstructed on the basis of visibility observations and observed and MM5-predicted winds with further validation against satellite data. We demonstrate that the combination of visibility data, TOMS aerosol index, MODIS aerosol optical depth over the land, and a qualitative analysis of MODIS and SeaWiFS imagery enables us to constrain the regions of origin of dust outbreaks and midrange transport, though various limitations of individual data sets were revealed in detecting dust over the land. Only two long-range transport episodes were found. The transport routes and coverage of these dust episodes were reconstructed by using MODIS aerosol optical depth and TOMS aerosol index. Our analysis reveals that over the oceans the presence of persistent clouds poses a main problem in identifying the regions affected by dust transport, so only partial reconstruction of dust transport routes reaching the

Global transport of thermophilic bacteria in atmospheric dust.

Science.gov (United States)

Perfumo, Amedea; Marchant, Roger

2010-04-01

Aerosols from dust storms generated in the Sahara-Sahel desert area of Africa are transported north over Europe and periodically result in dry dust precipitation in the Mediterranean region. Samples of dust collected in Turkey and Greece following two distinct desert storm events contained viable thermophilic organisms of the genus Geobacillus, namely G. thermoglucosidasius and G. thermodenitrificans, and the recently reclassified Aeribacillus pallidus (formerly Geobacillus pallidus). We present here evidence that African dust storms create an atmospheric bridge between distant geographical regions and that they are also probably the source of thermophilic geobacilli later deposited over northern Europe by rainfall or dust plumes themselves. The same organisms (99% similarity in the 16S rDNA sequence) were found in dust collected in the Mediterranean region and inhabiting cool soils in Northern Ireland. This study also contributes new insights to the taxonomic identification of Geobacillus sp. Attempts to identify these organisms using 16S rRNA gene sequences have revealed that they contain multiple and diverse copies of the ribosomal RNA operon (up to 10 copies with nine different sequences), which dictates care in interpreting data about the systematics of this genus. © 2010 Society for Applied Microbiology and Blackwell Publishing Ltd.

Long-range-transported bioaerosols captured in snow cover on Mount Tateyama, Japan: impacts of Asian-dust events on airborne bacterial dynamics relating to ice-nucleation activities

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T. Maki

2018-06-01

Full Text Available The westerly wind travelling at high altitudes over eastern Asia transports aerosols from the Asian deserts and urban areas to downwind areas such as Japan. These long-range-transported aerosols include not only mineral particles but also microbial particles (bioaerosols, that impact the ice-cloud formation processes as ice nuclei. However, the detailed relations of airborne bacterial dynamics to ice nucleation in high-elevation aerosols have not been investigated. Here, we used the aerosol particles captured in the snow cover at altitudes of 2450 m on Mt Tateyama to investigate sequential changes in the ice-nucleation activities and bacterial communities in aerosols and elucidate the relationships between the two processes. After stratification of the snow layers formed on the walls of a snow pit on Mt Tateyama, snow samples, including aerosol particles, were collected from 70 layers at the lower (winter accumulation and upper (spring accumulation parts of the snow wall. The aerosols recorded in the lower parts mainly came from Siberia (Russia, northern Asia and the Sea of Japan, whereas those in the upper parts showed an increase in Asian dust particles originating from the desert regions and industrial coasts of Asia. The snow samples exhibited high levels of ice nucleation corresponding to the increase in Asian dust particles. Amplicon sequencing analysis using 16S rRNA genes revealed that the bacterial communities in the snow samples predominately included plant associated and marine bacteria (phyla Proteobacteria during winter, whereas during spring, when dust events arrived frequently, the majority were terrestrial bacteria of phyla Actinobacteria and Firmicutes. The relative abundances of Firmicutes (Bacilli showed a significant positive relationship with the ice nucleation in snow samples. Presumably, Asian dust events change the airborne bacterial communities over Mt Tateyama and carry terrestrial bacterial populations, which

Long-range-transported bioaerosols captured in snow cover on Mount Tateyama, Japan: impacts of Asian-dust events on airborne bacterial dynamics relating to ice-nucleation activities

Science.gov (United States)

Maki, Teruya; Furumoto, Shogo; Asahi, Yuya; Lee, Kevin C.; Watanabe, Koichi; Aoki, Kazuma; Murakami, Masataka; Tajiri, Takuya; Hasegawa, Hiroshi; Mashio, Asami; Iwasaka, Yasunobu

2018-06-01

The westerly wind travelling at high altitudes over eastern Asia transports aerosols from the Asian deserts and urban areas to downwind areas such as Japan. These long-range-transported aerosols include not only mineral particles but also microbial particles (bioaerosols), that impact the ice-cloud formation processes as ice nuclei. However, the detailed relations of airborne bacterial dynamics to ice nucleation in high-elevation aerosols have not been investigated. Here, we used the aerosol particles captured in the snow cover at altitudes of 2450 m on Mt Tateyama to investigate sequential changes in the ice-nucleation activities and bacterial communities in aerosols and elucidate the relationships between the two processes. After stratification of the snow layers formed on the walls of a snow pit on Mt Tateyama, snow samples, including aerosol particles, were collected from 70 layers at the lower (winter accumulation) and upper (spring accumulation) parts of the snow wall. The aerosols recorded in the lower parts mainly came from Siberia (Russia), northern Asia and the Sea of Japan, whereas those in the upper parts showed an increase in Asian dust particles originating from the desert regions and industrial coasts of Asia. The snow samples exhibited high levels of ice nucleation corresponding to the increase in Asian dust particles. Amplicon sequencing analysis using 16S rRNA genes revealed that the bacterial communities in the snow samples predominately included plant associated and marine bacteria (phyla Proteobacteria) during winter, whereas during spring, when dust events arrived frequently, the majority were terrestrial bacteria of phyla Actinobacteria and Firmicutes. The relative abundances of Firmicutes (Bacilli) showed a significant positive relationship with the ice nucleation in snow samples. Presumably, Asian dust events change the airborne bacterial communities over Mt Tateyama and carry terrestrial bacterial populations, which possibly induce ice

Study on an intense dust storm over Greece

Science.gov (United States)

Kaskaoutis, D. G.; Kambezidis, H. D.; Nastos, P. T.; Kosmopoulos, P. G.

Springtime constitutes the most favorable period for Sahara dust outbreaks and transport over Eastern Mediterranean. This study investigates the aerosol properties during April 2005 using remote-sensing and ground-based measurements. Three dust events with high aerosol optical depth (AOD) values have been observed during the measuring period, with duration of two days, i.e. 11-12, 16-17 and 25-26 April 2005. In this paper we mainly focus on the intense dust event of 16-17 April 2005, when a thick dust layer transported from Libya affected the whole Greek territory. Very high AOD values obtained from Aqua-MODIS sensor were observed over Greece (mean 2.42 ± 1.25) on 17 April, while the respective mean April value was 0.31 ± 0.09. The AOD at 550 nm (AOD 550) values over Crete were even larger, reaching ˜4.0. As a consequence, the PM 10 concentrations over Athens dramatically increased reaching up to 200 μg m -3. On the other hand, the fine-mode fraction values obtained from Terra-MODIS showed a substantial decrease in the whole Greek area on 17 April with values below 0.2 in the Southern regions. The intense dust layer showed a complex behavior concerning its spatial and temporal evolution and allowed us to study the changes in the optical properties of the desert dust particles along their transport routes due to the mixing processes with other aerosol types. The results from different measurements (ground-based and remote-sensing) did not contradict each other and, therefore, are adequate for monitoring of dust load over the Eastern Mediterranean.

Extreme dust storm over the eastern Mediterranean in September 2015: satellite, lidar, and surface observations in the Cyprus region

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R.-E. Mamouri

2016-11-01

Full Text Available A record-breaking dust storm originating from desert regions in northern Syria and Iraq occurred over the eastern Mediterranean in September 2015. In this contribution of a series of two articles (part 1, observations; part 2, atmospheric modeling, we provide a comprehensive overview of the aerosol conditions during this extreme dust outbreak in the Cyprus region. These observations are based on satellite observations (MODIS, moderate resolution imaging spectroradiometer of aerosol optical thickness (AOT and Ångström exponent, surface particle mass (PM10 concentrations measured at four sites in Cyprus, visibility observations at three airports in southern Cyprus and corresponding conversion products (particle extinction coefficient, dust mass concentrations, EARLINET (European Aerosol Research Lidar Network lidar observations of dust vertical layering over Limassol, particle optical properties (backscatter, extinction, lidar ratio, linear depolarization ratio, and derived profiles of dust mass concentrations. Maximum 550 nm AOT exceeded values of 5.0, according to MODIS, and the mass loads were correspondingly >  10 g m−2 over Larnaca and Limassol during the passage of an extremely dense dust front on 8 September 2015. Hourly mean PM10 values were close to 8000 µg m−3 and the observed meteorological optical range (visibility was reduced to 300–750 m at Larnaca and Limassol. The visibility observations suggest peak values of the near-surface total suspended particle (TSP extinction coefficients of 6000 Mm−1 and thus TSP mass concentrations of 10 000 µg m−3. The Raman polarization lidar observations mainly indicated a double layer structure of the dust plumes (reaching to about 4 km height, pointing to at least two different dust source regions. Dust particle extinction coefficients (532 nm already exceeded 1000 Mm−1 and the mass concentrations reached 2000 µg m−3 in the elevated dust layers on

The impact of Pacific Decadal Oscillation on springtime dust activity in Syria

Science.gov (United States)

Pu, B.; Ginoux, P. A.

2016-12-01

The increasing trend of aerosol optical depth in the Middle East and a recent severe dust storm in Syria have raised questions as whether dust storms will increase and promoted investigations on the dust activities driven by the natural climate variability underlying the ongoing human perturbations such as the Syrian civil war. This study examined the influences of the Pacific decadal oscillation (PDO) on dust activities in Syria using an innovative dust optical depth (DOD) dataset derived from Moderate Resolution Imaging Spectroradiometer (MODIS) Deep Blue aerosol products. A significantly negative correlation is found between the Syrian DOD and the PDO in spring from 2003-2015. High DOD in spring is associated with lower geopotential height over the Middle East, Europe, and North Africa, accompanied by near surface anomalous westerly winds over the Mediterranean basin and southerly winds over the eastern Arabian Peninsula. These large-scale patterns promote the formation of the cyclones over the Middle East to trigger dust storms and also facilitate the transport of dust from North Africa, Iraq, and Saudi Arabian to Syria, where the transported dust dominates the seasonal mean DOD in spring. A negative PDO not only creates circulation anomalies favorable to high DOD in Syria but also suppresses precipitation in dust source regions over the eastern and southern Arabian Peninsula and northeastern Africa. On the daily scale, in addition to the favorable large-scale condition associated with a negative PDO, enhanced atmospheric instability in Syria associated with increased precipitation in Turkey and northern Syria is also critical for the development of strong springtime dust storms in Syria.

The Dust Storm Index (DSI): A method for monitoring broadscale wind erosion using meteorological records

Science.gov (United States)

O'Loingsigh, T.; McTainsh, G. H.; Tews, E. K.; Strong, C. L.; Leys, J. F.; Shinkfield, P.; Tapper, N. J.

2014-03-01

Wind erosion of soils is a natural process that has shaped the semi-arid and arid landscapes for millennia. This paper describes the Dust Storm Index (DSI); a methodology for monitoring wind erosion using Australian Bureau of Meteorology (ABM) meteorological observational data since the mid-1960s (long-term), at continental scale. While the 46 year length of the DSI record is its greatest strength from a wind erosion monitoring perspective, there are a number of technical challenges to its use because when the World Meteorological Organisation (WMO) recording protocols were established the use of the data for wind erosion monitoring was never intended. Data recording and storage protocols are examined, including the effects of changes to the definition of how observers should interpret and record dust events. A method is described for selecting the 180 long-term ABM stations used in this study and the limitations of variable observation frequencies between stations are in part resolved. The rationale behind the DSI equation is explained and the examples of temporal and spatial data visualisation products presented include; a long term national wind erosion record (1965-2011), continental DSI maps, and maps of the erosion event types that are factored into the DSI equation. The DSI is tested against dust concentration data and found to provide an accurate representation of wind erosion activity. As the ABM observational records used here were collected according to WMO protocols, the DSI methodology could be used in all countries with WMO-compatible meteorological observation and recording systems.

Decreased Pulmonary Function in School Children in Western Japan after Exposures to Asian Desert Dusts and Its Association with Interleukin-8

Directory of Open Access Journals (Sweden)

Masanari Watanabe

2015-01-01

Full Text Available The objective of the study was to investigate the influence of Asian dust storms (ADS on pulmonary function of school children and the relationship of this effect with interleukin-8. Morning peak expiratory flow (PEF was measured daily in 399 children from April to May 2012 and in 384 of these children from March to May 2013. The data were analyzed for an association between ADS events and PEF by linear mixed models. Interleukin-8 transcriptional activity was assessed in THP-G8 cells stimulated by airborne particles collected on ADS days. Seven ADS days were identified: April 23 and 24, 2012; March 8 to 10, 2013; and March 19 and 20, 2013. Changes in PEF after ADS exposure were −8.17 L/min (95% confidence interval, −11.40 to −4.93 in 2012 and −1.17 L/min (−4.07 to 1.74 in 2013, and there was a significant difference between 2012 and 2013. Interleukin-8 transcriptional activity was significantly higher in 2012 at 10.6±2.9-fold compared to 3.7±0.4 in March 8 to 10, 2013, and 2.3±0.2 in March 19 and 20, 2013. The influence of ADS events on pulmonary function of children differs with each ADS event and may be related to interleukin-8 production.

Decreased Pulmonary Function in School Children in Western Japan after Exposures to Asian Desert Dusts and Its Association with Interleukin-8

Science.gov (United States)

Watanabe, Masanari; Kurai, Jun; Sano, Hiroyuki; Saito, Rumiko; Kimura, Yutaka; Aiba, Setsuya; Oshimura, Mitsuo; Yamasaki, Akira; Shimizu, Eiji

2015-01-01

The objective of the study was to investigate the influence of Asian dust storms (ADS) on pulmonary function of school children and the relationship of this effect with interleukin-8. Morning peak expiratory flow (PEF) was measured daily in 399 children from April to May 2012 and in 384 of these children from March to May 2013. The data were analyzed for an association between ADS events and PEF by linear mixed models. Interleukin-8 transcriptional activity was assessed in THP-G8 cells stimulated by airborne particles collected on ADS days. Seven ADS days were identified: April 23 and 24, 2012; March 8 to 10, 2013; and March 19 and 20, 2013. Changes in PEF after ADS exposure were −8.17 L/min (95% confidence interval, −11.40 to −4.93) in 2012 and −1.17 L/min (−4.07 to 1.74) in 2013, and there was a significant difference between 2012 and 2013. Interleukin-8 transcriptional activity was significantly higher in 2012 at 10.6 ± 2.9-fold compared to 3.7 ± 0.4 in March 8 to 10, 2013, and 2.3 ± 0.2 in March 19 and 20, 2013. The influence of ADS events on pulmonary function of children differs with each ADS event and may be related to interleukin-8 production. PMID:26060816

Lead isotopes combined with a sequential extraction procedure for source apportionment in the dry deposition of Asian dust and non-Asian dust

International Nuclear Information System (INIS)

Lee, Pyeong-Koo; Yu, Soonyoung

2016-01-01

Lead isotopic compositions were determined in leachates that were generated using sequential extractions of dry deposition samples of Asian dust (AD) and non-Asian dust (NAD) and Chinese desert soils, and used to apportion Pb sources. Results showed significant differences in "2"0"6Pb/"2"0"7Pb and "2"0"6Pb/"2"0"4Pb isotopic compositions in non-residual fractions between the dry deposition samples and the Chinese desert soils while "2"0"6Pb/"2"0"7Pb and "2"0"6Pb/"2"0"4Pb isotopic compositions in residual fraction of the dry deposition of AD and NAD were similar to the mean "2"0"6Pb/"2"0"7Pb and "2"0"6Pb/"2"0"4Pb in residual fraction of the Alashan Plateau soil. These results indicate that the geogenic materials of the dry deposition of AD and NAD were largely influenced by the Alashan Plateau soil, while the secondary sources of the dry deposition were different from those of the Chinese desert soils. In particular, the lead isotopic compositions in non-residual fractions of the dry deposition were homogenous, which implies that the non-residual four fractions (F1 to F4) shared the primary anthropogenic origin. "2"0"6Pb/"2"0"7Pb values and the predominant wind directions in the study area suggested that airborne particulates of heavily industrialized Chinese cities were one of the main Pb sources. Source apportionment calculations showed that the average proportion of anthropogenic Pb in the dry deposition of AD and NAD was 87% and 95% respectively in total Pb extraction, 92% and 97% in non-residual fractions, 15% and 49% in residual fraction. Approximately 81% and 80% of the anthropogenic Pb was contributed by coal combustion in China in the dry deposition of AD and NAD respectively while the remainder was derived from industrial Pb contamination. The research result proposes that sequential extractions with Pb isotope analysis are a useful tool for the discrimination of anthropogenic and geogenic origins in highly contaminated AD and NAD. - Highlights: �

Dust, Pollution, and Biomass Burning Aerosols in Asian Pacific: A Column Satellite-Surface Perspective

Science.gov (United States)

Tsay, Si-Chee

2004-01-01

Airborne dusts from northern China contribute a significant part of the air quality problem and, to some extent, regional climatic impact in Asia during spring-time. However, with the economical growth in China, increases in the emission of air pollutants generated from industrial and vehicular sources will not only impact the radiation balance, but adverse health effects to humans all year round. In addition, both of these dust and air pollution clouds can transport swiftly across the Pacific reaching North America within a few days, possessing an even larger scale effect. The Asian dust and air pollution aerosols can be detected by its colored appearance on current Earth observing satellites (e.g., MODIS, SeaWiFS, TOMS, etc.) and its evolution monitored by satellites and surface network. Biomass burning has been a regular practice for land clearing and land conversion in many countries, especially those in Africa, South America, and Southeast Asia. However, the unique climatology of Southeast Asia is very different than that of Africa and South America, such that large-scale biomass burning causes smoke to interact extensively with clouds during the peak-burning season of March to April. Significant global sources of greenhouse gases (e.g., CO2, CH4), chemically active gases (e.g., NO, CO, HC, CH3Br), and atmospheric aerosols are produced by biomass burning processes. These gases influence the Earth-atmosphere system, impacting both global climate and tropospheric chemistry. Some aerosols can serve as cloud condensation nuclei, which play an important role in determining cloud lifetime and precipitation, hence, altering the earth's radiation and water budget. Biomass burning also affects the biogeochemical cycling of nitrogen and carbon compounds from the soil to the atmosphere; the hydrological cycle (i.e., run off and evaporation); land surface reflectivity and emissivity; as well as ecosystem biodiversity and stability. Two new initiatives, EAST-AIRE (East

Three-dimensional variational assimilation of MODIS aerosol optical depth: Implementation and application to a dust storm over East Asia

Science.gov (United States)

Liu, Zhiquan; Liu, Quanhua; Lin, Hui-Chuan; Schwartz, Craig S.; Lee, Yen-Huei; Wang, Tijian

2011-12-01

Assimilation of the Moderate Resolution Imaging Spectroradiometer (MODIS) total aerosol optical depth (AOD) retrieval products (at 550 nm wavelength) from both Terra and Aqua satellites have been developed within the National Centers for Environmental Prediction (NCEP) Gridpoint Statistical Interpolation (GSI) three-dimensional variational (3DVAR) data assimilation system. This newly developed algorithm allows, in a one-step procedure, the analysis of 3-D mass concentration of 14 aerosol variables from the Goddard Chemistry Aerosol Radiation and Transport (GOCART) module. The Community Radiative Transfer Model (CRTM) was extended to calculate AOD using GOCART aerosol variables as input. Both the AOD forward model and corresponding Jacobian model were developed within the CRTM and used in the 3DVAR minimization algorithm to compute the AOD cost function and its gradient with respect to 3-D aerosol mass concentration. The impact of MODIS AOD data assimilation was demonstrated by application to a dust storm from 17 to 24 March 2010 over East Asia. The aerosol analyses initialized Weather Research and Forecasting/Chemistry (WRF/Chem) model forecasts. Results indicate that assimilating MODIS AOD substantially improves aerosol analyses and subsequent forecasts when compared to MODIS AOD, independent AOD observations from the Aerosol Robotic Network (AERONET) and Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument, and surface PM10 (particulate matter with diameters less than 10 μm) observations. The newly developed AOD data assimilation system can serve as a tool to improve simulations of dust storms and general air quality analyses and forecasts.

Ecological Restoration Programs Induced Amelioration of the Dust Pollution in North China Plain

Science.gov (United States)

Long, X.; Tie, X.; Li, G.; Junji, C.

2017-12-01

With Moderate Resolution Imaging Spectroradiometer (MODIS) land cover product (MCD12Q1), we quantitatively evaluate the ecological restoration programs (ERP) induced land cover change in China by calculating gridded the land use fraction (LUF). We clearly capture two obvious vegetation (grass and forest) protective barriers arise between the dust source region DSR and North China Plain NCP from 2011 to 2013. The WRF-DUST model is applied to investigate the impact of ERPs on dust pollution from 2 to 8 March 2016, corresponding to a national dust storm event over China. Despite some model biases, the WRF-DUST model reasonably reproduced the temporal variations of dust storm event, involving IOA of 0.96 and NMB of 2% for DSR, with IOA of 0.83 and NMB of -15% for downwind area of NCP. Generally, the WRF-DUST model well capture the spatial variations and evolutions of dust storm events with episode-average [PMC] correlation coefficient (R) of 0.77, especially the dust storm outbreak and transport evolution, involving daily average [PMC] R of 0.9 and 0.73 on 4-5 March, respectively. It is found that the ERPs generally reduce the dust pollution in NCP, especially for BTH, involving upper dust pollution control benefits of -15.3% (-21.0 μg m-3) for BTH, and -6.2% (-9.3 μg m-3) for NCP. We are the first to conduct model sensitivity studies to quantitatively evaluate the impacts of the ERPs on the dust pollution in NCP. And our narrative is independently based on first-hand sources, whereas government statistics.

Enhancement and identification of dust events in the south-west ...

Indian Academy of Sciences (India)

in dust source regions, which have a negative impact on human health ... Keywords. MODIS; dust storm; visible; infrared; remote sensing; brightness temperature. 1 ... clouds can often be misinterpreted as dust. In order to ... dust aerosol outbreaks over land using satellite ... models were also used to track air parcels arriving.

Application of wind-profiling radar data to the analysis of dust weather in the Taklimakan Desert.

Science.gov (United States)

Wang, Minzhong; Wei, Wenshou; Ruan, Zheng; He, Qing; Ge, Runsheng

2013-06-01

The Urumqi Institute of Desert Meteorology of the China Meteorological Administration carried out an atmospheric scientific experiment to detect dust weather using a wind-profiling radar in the hinterland of the Taklimakan Desert in April 2010. Based on the wind-profiling data obtained from this experiment, this paper seeks to (a) analyze the characteristics of the horizontal wind field and vertical velocity of a breaking dust weather in a desert hinterland; (b) calculate and give the radar echo intensity and vertical distribution of a dust storm, blowing sand, and floating dust weather; and (c) discuss the atmosphere dust counts/concentration derived from the wind-profiling radar data. Studies show that: (a) A wind-profiling radar is an upper-air atmospheric remote sensing system that effectively detects and monitors dust. It captures the beginning and ending of a dust weather process as well as monitors the sand and dust being transported in the air in terms of height, thickness, and vertical intensity. (b) The echo intensity of a blowing sand and dust storm weather episode in Taklimakan is about -1~10 dBZ while that of floating dust -1~-15 dBZ, indicating that the dust echo intensity is significantly weaker than that of precipitation but stronger than that of clear air. (c) The vertical shear of horizontal wind and the maintenance of low-level east wind are usually dynamic factors causing a dust weather process in Taklimakan. The moment that the low-level horizontal wind field finds a shear over time, it often coincides with the onset of a sand blowing and dust storm weather process. (d) When a blowing sand or dust storm weather event occurs, the atmospheric vertical velocity tends to be of upward motion. This vertical upward movement of the atmosphere supported with a fast horizontal wind and a dry underlying surface carries dust particles from the ground up to the air to form blown sand or a dust storm.

New insights into the vertical structure of the September 2015 dust storm employing eight ceilometers and auxiliary measurements over Israel

Science.gov (United States)

Uzan, Leenes; Egert, Smadar; Alpert, Pinhas

2018-03-01

On 7 September 2015, an unprecedented and unexceptional extreme dust storm struck the eastern Mediterranean (EM) basin. Here, we provide an overview of the previous studies and describe the dust plume evolution over a relatively small area, i.e., Israel. This study presents vertical profiles provided by an array of eight ceilometers covering the Israeli shore, inland and mountain regions. We employ multiple tools including spectral radiometers (Aerosol Robotic Network - AERONET), ground particulate matter concentrations, satellite images, global/diffuse/direct solar radiation measurements and radiosonde profiles. The main findings reveal that the dust plume penetrated Israel on 7 September from the northeast in a downward motion to southwest. On 8 September, the lower level of the dust plume reached 200 m above ground level, generating aerosol optical depth (AOD) above 3 and extreme ground particulate matter concentrations up to ˜ 10 000 µm m-3. A most interesting feature on 8 September was the very high variability in the surface solar radiation in the range of 200-600 W m-2 (22 sites) over just a distance of several hundred kilometers in spite of the thick dust layer above. Furthermore, 8 September shows the lowest radiation levels for this event. On the following day, the surface solar radiation increased, thus enabling a late (between 11:00 and 12:00 UTC) sea breeze development mainly in the coastal zone associated with a creation of a narrow dust layer detached from the ground. On 10 September, the AOD values started to drop down to ˜ 1.5, and the surface concentrations of particulate matter decreased as well as the ceilometers' aerosol indications (signal counts) although Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) revealed an upper dust layer remained.

Modeled Downward Transport of a Passive Tracer over Western North America during an Asian Dust Event in April 1998.

Science.gov (United States)

Hacker, Joshua P.; McKendry, Ian G.; Stull, Roland B.

2001-09-01

An intense Gobi Desert dust storm in April 1998 loaded the midtroposphere with dust that was transported across the Pacific to western North America. The Mesoscale Compressible Community (MC2) model was used to investigate mechanisms causing downward transport of the midtropospheric dust and to explain the high concentrations of particulate matter of less than 10-m diameter measured in the coastal urban areas of Washington and southern British Columbia. The MC2 was initialized with a thin, horizontally homogeneous layer of passive tracer centered at 650 hPa for a simulation from 0000 UTC 26 April to 0000 UTC 30 April 1998. Model results were in qualitative agreement with observed spatial and temporal patterns of particulate matter, indicating that it captured the important meteorological processes responsible for the horizontal and vertical transport over the last few days of the dust event. A second simulation was performed without topography to isolate the effects of topography on downward transport.Results show that the dust was advected well east of the North American coast in southwesterly midtropospheric flow, with negligible dust concentration reaching the surface initially. Vertically propagating mountain waves formed during this stage, and differences between downward and upward velocities in these waves could account for a rapid descent of dust to terrain height, where the dust was entrained into the turbulent planetary boundary layer. A deepening outflow (easterly) layer near the surface transported the tracer westward and created a zonal-shear layer that further controlled the tracer advection. Later, the shear layer lifted, leading to a downward hydraulic acceleration along the western slopes, as waves generated in the easterly flow amplified below the shear layer that was just above mountain-crest height. Examination of 10 yr of National Centers for Environmental Prediction-National Center for Atmospheric Research reanalyses suggests that such events

The impact of the Pacific Decadal Oscillation on springtime dust activity in Syria

Directory of Open Access Journals (Sweden)

B. Pu

2016-10-01

Full Text Available The increasing trend of aerosol optical depth in the Middle East and a recent severe dust storm in Syria have raised questions as to whether dust storms will increase and promoted investigations on the dust activities driven by the natural climate variability underlying the ongoing human perturbations such as the Syrian civil war. This study examined the influences of the Pacific Decadal Oscillation (PDO on dust activities in Syria using an innovative dust optical depth (DOD dataset derived from Moderate Resolution Imaging Spectroradiometer (MODIS Deep Blue aerosol products. A significantly negative correlation is found between the Syrian DOD and the PDO in spring from 2003 to 2015. High DOD in spring is associated with lower geopotential height over the Middle East, Europe, and North Africa, accompanied by near-surface anomalous westerly winds over the Mediterranean basin and southerly winds over the eastern Arabian Peninsula. These large-scale patterns promote the formation of the cyclones over the Middle East to trigger dust storms and also facilitate the transport of dust from North Africa, Iraq, and Saudi Arabia to Syria, where the transported dust dominates the seasonal mean DOD in spring. A negative PDO not only creates circulation anomalies favorable to high DOD in Syria but also suppresses precipitation in dust source regions over the eastern and southern Arabian Peninsula and northeastern Africa.On the daily scale, in addition to the favorable large-scale condition associated with a negative PDO, enhanced atmospheric instability in Syria (associated with increased precipitation in Turkey and northern Syria is also critical for the development of strong springtime dust storms in Syria.

The impact of the Pacific Decadal Oscillation on springtime dust activity in Syria

Science.gov (United States)

Pu, Bing; Ginoux, Paul

2016-10-01

The increasing trend of aerosol optical depth in the Middle East and a recent severe dust storm in Syria have raised questions as to whether dust storms will increase and promoted investigations on the dust activities driven by the natural climate variability underlying the ongoing human perturbations such as the Syrian civil war. This study examined the influences of the Pacific Decadal Oscillation (PDO) on dust activities in Syria using an innovative dust optical depth (DOD) dataset derived from Moderate Resolution Imaging Spectroradiometer (MODIS) Deep Blue aerosol products. A significantly negative correlation is found between the Syrian DOD and the PDO in spring from 2003 to 2015. High DOD in spring is associated with lower geopotential height over the Middle East, Europe, and North Africa, accompanied by near-surface anomalous westerly winds over the Mediterranean basin and southerly winds over the eastern Arabian Peninsula. These large-scale patterns promote the formation of the cyclones over the Middle East to trigger dust storms and also facilitate the transport of dust from North Africa, Iraq, and Saudi Arabia to Syria, where the transported dust dominates the seasonal mean DOD in spring. A negative PDO not only creates circulation anomalies favorable to high DOD in Syria but also suppresses precipitation in dust source regions over the eastern and southern Arabian Peninsula and northeastern Africa.On the daily scale, in addition to the favorable large-scale condition associated with a negative PDO, enhanced atmospheric instability in Syria (associated with increased precipitation in Turkey and northern Syria) is also critical for the development of strong springtime dust storms in Syria.

Ozone Production by Colliding Dust in the Martian Atmosphere

Science.gov (United States)

Baragiola, R. A.; Dukes, C. A.

2012-03-01

Laboratory studies show that ozone is produced by electrical discharges when rocks fracture. We propose that a similar process should occur in the collision of dust particles during dust storms in Mars and discuss implications.

Characterization of synoptic patterns causing dust outbreaks that affect the Arabian Peninsula

Science.gov (United States)

Hermida, L.; Merino, A.; Sánchez, J. L.; Fernández-González, S.; García-Ortega, E.; López, L.

2018-01-01

Dust storms pose serious weather hazards in arid and semiarid regions of the earth. Understanding the main synoptic conditions that give rise to dust outbreaks is important for issuing forecasts and warnings to the public in cases of severe storms. The aim of the present study is to determine synoptic patterns that are associated with or even favor dust outbreaks over the Arabian Peninsula. In this respect, red-green-blue dust composite images from the Meteosat Second Generation (MSG) satellite are used to detect dust outbreaks affecting the Arabian Peninsula, with possible influences in southwestern Asia and northeastern Africa, between 2005 and 2013. The Meteosat imagery yielded a sample of 95 dust storm days. Meteorological fields from NCEP/NCAR reanalysis data of wind fields at 10 m and 250 hPa, mean sea level pressure, and geopotential heights at 850 and 500 hPa were obtained for the dust storm days. Using principal component analysis in T-mode and non-hierarchical k-means clustering, we obtained four major atmospheric circulation patterns associated with dust outbreaks during the study days. Cluster 4 had the largest number of days with dust events, which were constrained to summer, and cluster 3 had the fewest. In clusters 1, 2 and 3, the jet stream favored the entry of a low-pressure area or trough that varied in location between the three clusters. Their most northerly location was found in cluster 4, along with an extensive low-pressure area supporting strong winds over the Arabian Peninsula. The spatial distribution of aerosol optical depth for each cluster obtained was characterized using the Moderate Resolution Imaging Spectroradiometer data. Then, using METAR stations, clusters were also characterized in terms of frequency and visibility.

Coupling the Mars Dust and Water Cycles: Investigating the Role of Clouds in Controlling the Vertical Distribution of Dust During N. H. Summer

Science.gov (United States)

Kahre, M. A.; Haberle, R. M.; Hollingsworth, J. L.; Wilson, R. J.

2014-01-01

The dust cycle is critically important for the current climate of Mars. The radiative effects of dust impact the thermal and dynamical state of the atmosphere (Gierasch and Goody, 1968; Haberle et al., 1982; Zurek et al., 1992). Although dust is present in the Martian atmosphere throughout the year, the level of dustiness varies with season. The atmosphere is generally the dustiest during northern fall and winter and the least dusty during northern spring and summer (Smith, 2004). Dust particles are lifted into the atmosphere by dust storms that range in size from meters to thousands of kilometers across (Cantor et al., 2001). During some years, regional storms combine to produce hemispheric or planet encircling dust clouds that obscure the surface and raise atmospheric temperatures by as much as 40 K (Smith et al., 2002). Key recent observations of the vertical distribution of dust indicate that elevated layers of dust exist in the tropics and sub-tropics throughout much of the year (Heavens et al., 2011). These observations have brought particular focus on the processes that control the vertical distribution of dust in the Martian atmosphere. The goal of this work is to further our understanding of how clouds in particular control the vertical distribution of dust, particularly during N. H. spring and summer

Effects of two Asian sand dusts transported from the dust source regions of Inner Mongolia and northeast China on murine lung eosinophilia

Energy Technology Data Exchange (ETDEWEB)

He, Miao, E-mail: hemiao.cmu@gmail.com [Environment and Chronic Non-communicable Disease Research Center, College of Public Health, China Medical University, 11001 Shenyang (China); Department of Health Sciences, Oita University of Nursing and Health Sciences, 870-1201 Oita (Japan); Ichinose, Takamichi, E-mail: ichinose@oita-nhs.ac.jp [Department of Health Sciences, Oita University of Nursing and Health Sciences, 870-1201 Oita (Japan); Song, Yuan, E-mail: freude@med.uoeh-u.ac.jp [Department of Immunology and Parasitology, School of Medicine, University of Occupational and Environmental Health, Iseigaoka, Yahata-nishi-ku, Kitakyushu, 807-8555 Fukuoka (Japan); Yoshida, Yasuhiro, E-mail: songyuan1107@163.com [Department of Immunology and Parasitology, School of Medicine, University of Occupational and Environmental Health, Iseigaoka, Yahata-nishi-ku, Kitakyushu, 807-8555 Fukuoka (Japan); Arashidani, Keiichi, E-mail: arashi@snow.ocn.ne.jp [Department of Immunology and Parasitology, School of Medicine, University of Occupational and Environmental Health, Iseigaoka, Yahata-nishi-ku, Kitakyushu, 807-8555 Fukuoka (Japan); Yoshida, Seiichi, E-mail: syoshida@oita-nhs.ac.jp [Department of Health Sciences, Oita University of Nursing and Health Sciences, 870-1201 Oita (Japan); Liu, Boying, E-mail: boyingliu321@gmail.com [Environment and Chronic Non-communicable Disease Research Center, College of Public Health, China Medical University, 11001 Shenyang (China); Department of Health Sciences, Oita University of Nursing and Health Sciences, 870-1201 Oita (Japan); Nishikawa, Masataka, E-mail: mnishi@nies.go.jp [Environmental Chemistry Division, National Institute for Environmental Studies, 305-8506 Tsukuba, Ibaraki (Japan); Takano, Hirohisa, E-mail: htakano@health.env.kyoto-u.ac.jp [Environmental Health Division, Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto 615-8530 (Japan); and others

2013-11-01

The quality and quantity of toxic materials adsorbed onto Asian sand dust (ASD) are different based on dust source regions and passage routes. The aggravating effects of two ASDs (ASD1 and ASD2) transported from the source regions of Inner Mongolia and northeast China on lung eosinophilia were compared to clarify the role of toxic materials in ASD. The ASDs contained different amounts of lipopolysaccharides (LPS) and β-glucan (ASD1 < ASD2) and SiO{sub 2} (ASD1 > ASD2). CD-1 mice were instilled intratracheally with ASD1, ASD2 and/or ovalbumin (OVA) four times at 2-week intervals. ASD1 and ASD2 enhanced eosinophil recruitment induced by OVA in the submucosa of the airway, with goblet cell proliferation in the bronchial epithelium. ASD1 and ASD2 synergistically increased OVA-induced eosinophil-relevant cytokines interleukin-5 (IL-5), IL-13 (ASD1 < ASD2) and chemokine eotaxin (ASD1 > ASD2) in bronchoalveolar lavage fluid. ASD2 aggravating effects on lung eosinophilia were greater than ASD1. The role of LPS and β-glucan in ASD2 on the production of pro-inflammatory mediators was assessed using in vitro bone marrow-derived macrophages (BMDMs) from wild type, Toll-like receptor 2-deficient (TLR2 −/−), TLR4 −/−, and MyD88 −/− mice (on Balb/c background). ASD2-stimulated TLR2 −/− BMDMs enhanced IL-6, IL-12, TNF-α, MCP-1 and MIP-1α secretion compared with ASD2-stimulated TLR4 −/− BMDMs. Protein expression from ASD2-stimulated MyD88 −/− BMDM were very low or undetectable. The in vitro results indicate that lung eosinophilia caused by ASD is TLR4 dependent. Therefore, the aggravation of OVA-related lung eosinophilia by ASD may be dependent on toxic substances derived from microbes, such as LPS, rather than SiO{sub 2}. - Highlights: • Asian sand dust (ASD) from the deserts of China causes serious respiratory problems. • The aggravating effects of two ASDs on lung eosinophilia were compared. • The ASDs contained different LPS and β-glucan (ASD1

Effects of two Asian sand dusts transported from the dust source regions of Inner Mongolia and northeast China on murine lung eosinophilia

International Nuclear Information System (INIS)

He, Miao; Ichinose, Takamichi; Song, Yuan; Yoshida, Yasuhiro; Arashidani, Keiichi; Yoshida, Seiichi; Liu, Boying; Nishikawa, Masataka; Takano, Hirohisa

2013-01-01

The quality and quantity of toxic materials adsorbed onto Asian sand dust (ASD) are different based on dust source regions and passage routes. The aggravating effects of two ASDs (ASD1 and ASD2) transported from the source regions of Inner Mongolia and northeast China on lung eosinophilia were compared to clarify the role of toxic materials in ASD. The ASDs contained different amounts of lipopolysaccharides (LPS) and β-glucan (ASD1 2 (ASD1 > ASD2). CD-1 mice were instilled intratracheally with ASD1, ASD2 and/or ovalbumin (OVA) four times at 2-week intervals. ASD1 and ASD2 enhanced eosinophil recruitment induced by OVA in the submucosa of the airway, with goblet cell proliferation in the bronchial epithelium. ASD1 and ASD2 synergistically increased OVA-induced eosinophil-relevant cytokines interleukin-5 (IL-5), IL-13 (ASD1 ASD2) in bronchoalveolar lavage fluid. ASD2 aggravating effects on lung eosinophilia were greater than ASD1. The role of LPS and β-glucan in ASD2 on the production of pro-inflammatory mediators was assessed using in vitro bone marrow-derived macrophages (BMDMs) from wild type, Toll-like receptor 2-deficient (TLR2 −/−), TLR4 −/−, and MyD88 −/− mice (on Balb/c background). ASD2-stimulated TLR2 −/− BMDMs enhanced IL-6, IL-12, TNF-α, MCP-1 and MIP-1α secretion compared with ASD2-stimulated TLR4 −/− BMDMs. Protein expression from ASD2-stimulated MyD88 −/− BMDM were very low or undetectable. The in vitro results indicate that lung eosinophilia caused by ASD is TLR4 dependent. Therefore, the aggravation of OVA-related lung eosinophilia by ASD may be dependent on toxic substances derived from microbes, such as LPS, rather than SiO 2 . - Highlights: • Asian sand dust (ASD) from the deserts of China causes serious respiratory problems. • The aggravating effects of two ASDs on lung eosinophilia were compared. • The ASDs contained different LPS and β-glucan (ASD1 2 (ASD1 > ASD2). • The ASD2 aggravating effects on lung

The Spatio-Temporal Distribution of Particulate Matter during Natural Dust Episodes at an Urban Scale.

Directory of Open Access Journals (Sweden)

Helena Krasnov

Full Text Available Dust storms are a common phenomenon in arid and semi-arid areas, and their impacts on both physical and human environments are of great interest. Number of studies have associated atmospheric PM pollution in urban environments with origin in natural soil/dust, but less evaluated the dust spatial patterns over a city. We aimed to analyze the spatial-temporal behavior of PM concentrations over the city of Beer Sheva, in southern Israel, where dust storms are quite frequent. PM data were recorded during the peak of each dust episode simultaneously in 23 predetermined fixed points around the city. Data were analyzed for both dust days and non-dust days (background. The database was constructed using Geographic Information System and includes distributions of PM that were derived using inverse distance weighted (IDW interpolation. The results show that the daily averages of atmospheric PM10 concentrations during the background period are within a narrow range of 31 to 48 μg m-3 with low variations. During dust days however, the temporal variations are significant and can range from an hourly PM10 concentration of 100 μg m-3 to more than 1280 μg m-3 during strong storms. IDW analysis demonstrates that during the peak time of the storm the spatial variations in PM between locations in the city can reach 400 μg m-3. An analysis of site and storm contribution to total PM concentration revealed that higher concentrations are found in parts of the city that are proximal to dust sources. The results improve the understanding of the dynamics of natural PM and the dependence on wind direction. This may have implications for environmental and health outcomes.

Direct observations of the atmospheric processing of Asian mineral dust

Directory of Open Access Journals (Sweden)

R. C. Sullivan

2007-01-01

Full Text Available The accumulation of secondary acids and ammonium on individual mineral dust particles during ACE-Asia has been measured with an online single-particle mass spectrometer, the ATOFMS. Changes in the amounts of sulphate, nitrate, and chloride mixed with dust particles correlate with air masses from different source regions. The uptake of secondary acids depended on the individual dust particle mineralogy; high amounts of nitrate accumulated on calcium-rich dust while high amounts of sulphate accumulated on aluminosilicate-rich dust. Oxidation of S(IV to S(VI by iron in the aluminosilicate dust is a possible explanation for this enrichment of sulphate, which has important consequences for the fertilization of remote oceans by soluble iron. This study shows the segregation of sulphate from nitrate and chloride in individual aged dust particles for the first time. A transport and aging timeline provides an explanation for the observed segregation. Our data suggests that sulphate became mixed with the dust first. This implies that the transport pathway is more important than the reaction kinetics in determining which species accumulate on mineral dust. Early in the study, dust particles in volcanically influenced air masses were mixed predominately with sulphate. Dust mixed with chloride then dominated over sulphate and nitrate when a major dust front reached the R. V. Ronald Brown. We hypothesize that the rapid increase in chloride on dust was due to mixing with HCl(g released from acidified sea salt particles induced by heterogeneous reaction with volcanic SO2(g, prior to the arrival of the dust front. The amount of ammonium mixed with dust correlated strongly with the total amount of secondary acid reaction products in the dust. Submicron dust and ammonium sulphate were internally mixed, contrary to frequent reports that they exist as external mixtures. The size distribution of the mixing state of dust with these secondary species validates previous

Health risk assessment of exposure to the Middle-Eastern Dust storms in the Iranian megacity of Kermanshah.

Science.gov (United States)

Goudarzi, G; Daryanoosh, S M; Godini, H; Hopke, P K; Sicard, P; De Marco, A; Rad, H D; Harbizadeh, A; Jahedi, F; Mohammadi, M J; Savari, J; Sadeghi, S; Kaabi, Z; Omidi Khaniabadi, Y

2017-07-01

This study assessed the effects of particulate matter (PM), equal or less than 10 μm in aerodynamic diameter (PM 10 ), from the Middle-Eastern Dust events on public health in the megacity of Kermanshah (Iran). This study used epidemiological modeling and monitored ambient air quality data to estimate the potential PM 10 impacts on public health. The AirQ2.2.3 model was used to calculate mortality and morbidity attributed to PM 10 as representative of dust events. Using Visual Basic for Applications, the programming language of Excel software, hourly PM 10 concentrations obtained from the local agency were processed to prepare input files for the AirQ2.2.3 model. Using baseline incidence, defined by the World Health Organization, the number of estimated excess cases for respiratory mortality, hospital admissions for chronic obstructive pulmonary disease, for respiratory diseases, and for cardiovascular diseases were 37, 39, 476, and 184 persons, respectively, from 21st March, 2014 to 20th March, 2015. Furthermore, 92% of mortality and morbidity cases occurred in days with PM 10 concentrations lower than 150 μg/m 3 . The highest percentage of person-days occurred for daily concentrations range of 100-109 μg/m 3 , causing the maximum health end-points among the citizens of Kermanshah. Calculating the number of cumulative excess cases for mortality or morbidity attributed to PM 10 provides a good tool for decision and policy-makers in the field of health care to compensate their shortcomings particularly at hospital and healthcare centers for combating dust storms. To diminish these effects, several immediate actions should be managed in the governmental scale to control dust such as spreading mulch and planting new species that are compatible to arid area. Copyright © 2017 The Royal Society for Public Health. All rights reserved.

Asian Dust Weather Categorization with Satellite and Surface Observations

Science.gov (United States)

Lin, Tang-Huang; Hsu, N. Christina; Tsay, Si-Chee; Huang, Shih-Jen

2011-01-01

This study categorizes various dust weather types by means of satellite remote sensing over central Asia. Airborne dust particles can be identified by satellite remote sensing because of the different optical properties exhibited by coarse and fine particles (i.e. varying particle sizes). If a correlation can be established between the retrieved aerosol optical properties and surface visibility, the intensity of dust weather can be more effectively and consistently discerned using satellite rather than surface observations. In this article, datasets consisting of collocated products from Moderate Resolution Imaging Spectroradiometer Aqua and surface measurements are analysed. The results indicate an exponential relationship between the surface visibility and the satellite-retrieved aerosol optical depth, which is subsequently used to categorize the dust weather. The satellite-derived spatial frequency distributions in the dust weather types are consistent with China s weather station reports during 2003, indicating that dust weather classification using satellite data is highly feasible. Although the period during the springtime from 2004 to 2007 may be not sufficient for statistical significance, our results reveal an increasing tendency in both intensity and frequency of dust weather over central Asia during this time period.

Modification of Asian-dust particles transported by different routes - A case study

Science.gov (United States)

Zaizen, Yuji; Naoe, Hiroaki; Takahashi, Hiroshi; Okada, Kikuo

2014-11-01

Two separate Asian dust events occurred before and after the passage of a cold front over Japan on 21 March 2010. According to back trajectories and a model simulation, the two dusty air-masses originated from the same region in Mongoria or northern China and were transported over different routes to Japan. Samples of aerosol particles from both airmasses were collected at Tsukuba and Mt. Haruna and examined by single-particle analysis using a transmission electron microscope and an energy dispersive X-ray analyzer. The mixing properties of mineral aerosol were quite different in the two airmasses and size ranges. In the prefrontal airmass, which were associated with pollution, most of fine (mixed with sulfate. On the contrary, mineral aerosols in the postfront airmass, which were relatively natural, were mostly externally mixed. In the latter case, the internal mixing was associated with Ca, however in the former case, mixing processes not concerning mineralogy was suggested.

Simulating Mars' Dust Cycle with a Mars General Circulation Model: Effects of Water Ice Cloud Formation on Dust Lifting Strength and Seasonality

Science.gov (United States)

Kahre, Melinda A.; Haberle, Robert; Hollingsworth, Jeffery L.

2012-01-01

The dust cycle is critically important for the current climate of Mars. The radiative effects of dust impact the thermal and dynamical state of the atmosphere [1,2,3]. Although dust is present in the Martian atmosphere throughout the year, the level of dustiness varies with season. The atmosphere is generally the dustiest during northern fall and winter and the least dusty during northern spring and summer [4]. Dust particles are lifted into the atmosphere by dust storms that range in size from meters to thousands of kilometers across [5]. Regional storm activity is enhanced before northern winter solstice (Ls200 degrees - 240 degrees), and after northern solstice (Ls305 degrees - 340 degrees ), which produces elevated atmospheric dust loadings during these periods [5,6,7]. These pre- and post- solstice increases in dust loading are thought to be associated with transient eddy activity in the northern hemisphere with cross-equatorial transport of dust leading to enhanced dust lifting in the southern hemisphere [6]. Interactive dust cycle studies with Mars General Circulation Models (MGCMs) have included the lifting, transport, and sedimentation of radiatively active dust. Although the predicted global dust loadings from these simulations capture some aspects of the observed dust cycle, there are marked differences between the simulated and observed dust cycles [8,9,10]. Most notably, the maximum dust loading is robustly predicted by models to occur near northern winter solstice and is due to dust lifting associated with down slope flows on the flanks of the Hellas basin. Thus far, models have had difficulty simulating the observed pre- and post- solstice peaks in dust loading.

Coupling Mars' Dust and Water Cycles: Effects on Dust Lifting Vigor, Spatial Extent and Seasonality

Science.gov (United States)

Kahre, M. A.; Hollingsworth, J. L.; Haberle, R. M.; Montmessin, F.

2012-01-01

The dust cycle is an important component of Mars' current climate system. Airborne dust affects the radiative balance of the atmosphere, thus greatly influencing the thermal and dynamical state of the atmosphere. Dust raising events on Mars occur at spatial scales ranging from meters to planet-wide. Although the occurrence and season of large regional and global dust storms are highly variable from one year to the next, there are many features of the dust cycle that occur year after year. Generally, a low-level dust haze is maintained during northern spring and summer, while elevated levels of atmospheric dust occur during northern autumn and winter. During years without global-scale dust storms, two peaks in total dust loading were observed by MGS/TES: one peak occurred before northern winter solstice at Ls 200-240, and one peak occurred after northern winter solstice at L(sub s) 305-340. These maxima in dust loading are thought to be associated with transient eddy activity in the northern hemisphere, which has been observed to maximize pre- and post-solstice. Interactive dust cycle studies with Mars General Circulation Models (MGCMs) have included the lifting, transport, and sedimentation of radiatively active dust. Although the predicted global dust loadings from these simulations capture some aspects of the observed dust cycle, there are marked differences between the simulated and observed dust cycles. Most notably, the maximum dust loading is robustly predicted by models to occur near northern winter solstice and is due to dust lifting associated with down slope flows on the flanks of the Hellas basin. Thus far, models have had difficulty simulating the observed pre- and post- solstice peaks in dust loading. Interactive dust cycle studies typically have not included the formation of water ice clouds or their radiative effects. Water ice clouds can influence the dust cycle by scavenging dust from atmosphere and by interacting with solar and infrared radiation

The physics of wind-blown sand and dust.

Science.gov (United States)

Kok, Jasper F; Parteli, Eric J R; Michaels, Timothy I; Karam, Diana Bou

2012-10-01

The transport of sand and dust by wind is a potent erosional force, creates sand dunes and ripples, and loads the atmosphere with suspended dust aerosols. This paper presents an extensive review of the physics of wind-blown sand and dust on Earth and Mars. Specifically, we review the physics of aeolian saltation, the formation and development of sand dunes and ripples, the physics of dust aerosol emission, the weather phenomena that trigger dust storms, and the lifting of dust by dust devils and other small-scale vortices. We also discuss the physics of wind-blown sand and dune formation on Venus and Titan.

Airborne transport of Saharan dust to the Mediterranean and to the Atlantic

Energy Technology Data Exchange (ETDEWEB)

Pericleous, K.A.; Plainiotis, S. [Greenwich Univ., London (United Kingdom); Fisher, B.E.A. [Environment Agency, Reading (United Kingdom)

2006-07-01

A Lagrangian particle dispersion (LPD) model was used to predict the transport of sand particles and particulate matter (PM{sub 10}) exceedances attributed to Saharan storms in the Atlantic ocean near the United Kingdom, and in the Mediterranean Sea near Crete. Forward and reverse receptor modes were used to confirm the discovery of conflicting emission sources. Outputs were compared with satellite images and receptor data from multiple ground-based sites. Two models were used, notably the hybrid single particle Lagrangian integrated trajectory (HYSPLIT) model, and FLEXPART, an open source model. The emission model used to simulate dust emissions caused in a Sahara dust storm was based on the concept that threshold friction velocity was dependent on surface roughness. Case studies were presented for various Saharan dust episodes in the studied regions. Results of the study showed that the model accurately characterized sand entrainment in the atmosphere due to wind shear. It was concluded that coupled with advanced weather forecasting, the model can be used to predict the onset of desert dust storms well before their effects are felt. 15 refs., 6 figs.

Study of Radiative Forcing of Dust Aerosols and its impact on Climate Characteristics

KAUST Repository

Qureshi, Fawwad H

2012-12-01

The purpose of following project is to study the effect of dust aerosols on the radiative forcing which is directly related to the surface temperature. A single column radiative convective model is used for simulation purpose. A series of simulations have been performed by varying the amount of dust aerosols present in the atmosphere to study the trends in ground temperature, heating rate and radiative forcing for both its longwave and shortwave components. A case study for dust storm is also performed as dust storms are common in Arabian Peninsula. A sensitivity analyses is also performed to study the relationship of surface temperature minimum and maximum against aerosol concentration, single scattering albedo and asymmetry factor. These analyses are performed to get more insight into the role of dust aerosols on radiative forcing.

1500-year Record of trans-Pacific Dust Flux collected from the Denali Ice Core, Mt. Hunter, Alaska

Science.gov (United States)

Saylor, P. L.; Osterberg, E. C.; Koffman, B. G.; Winski, D.; Ferris, D. G.; Kreutz, K. J.; Wake, C. P.; Handley, M.; Campbell, S. W.

2016-12-01

Mineral dust aerosols are a critical component of the climate system through their influence on atmospheric radiative forcing, ocean productivity, and surface albedo. Dust aerosols derived from Asian deserts are known to reach as far as Europe through efficient transport in the upper tropospheric westerlies. While centennially-to-millennially resolved Asian dust records exist over the late Holocene from North Pacific marine sediment cores and Asian loess deposits, a high-resolution (sub-annual to decadal) record of trans-Pacific dust flux will significantly improve our understanding of North Pacific dust-climate interactions and provide paleoclimatological context for 20th century dust activity. Here we present an annually resolved 1500-year record of trans-Pacific dust transport based on chemical and physical dust measurements in parallel Alaskan ice cores (208 m to bedrock) collected from the summit plateau of Mt. Hunter in Denali National Park. The cores were sampled at high resolution using a continuous melter system with discrete analyses for major ions (Dionex ion chromatograph), trace elements (Element2 inductively coupled plasma mass spectrometer), and stable water isotope ratios (Picarro laser ringdown spectroscopy), and continuous flow analysis for dust concentration and size distribution (Klotz Abakus). We compare the ice core dust record to instrumental aerosol stations, satellite observations, and dust model data from the instrumental period, and evaluate climatic controls on dust emission and trans-Pacific transport using climate reanalysis data, to inform dust-climate relationships over the past 1500 years. Physical particulate and chemical data demonstrate remarkable fidelity at sub-annual resolution, with both displaying a strong springtime peak consistent with periods of high dust activity over Asian desert source regions. Preliminary results suggest volumetric mode typically ranges from 4.5 - 6.5 um, with a mean value of 5.5 um. Preliminary

Correlation between Asian Dust and Specific Radioactivities of Fission Products Included in Airborne Samples in Tokushima, Shikoku Island, Japan, Due to the Fukushima Nuclear Accident

International Nuclear Information System (INIS)

Sakama, M.; Nagano, Y.; Kitade, T.; Shikino, O.; Nakayama, S.

2014-01-01

Radioactive fission product 131 I released from the Fukushima Daiichi Nuclear Power Plants (FD-NPP) was first detected on March 23, 2011 in an airborne aerosol sample collected at Tokushima, Shikoku Island, located in western Japan. Two other radioactive fission products, 134 Cs and 137 Cs were also observed in a sample collected from April 2 to 4, 2011. The maximum specific radioactivities observed in this work were about 2.5 to 3.5 mBq×m -3 in a airborne aerosol sample collected on April 6. During the course of the continuous monitoring, we also made our first observation of seasonal Asian Dust and those fission products associated with the FDNPP accident concurrently from May 2 to 5, 2011. We found that the specific radioactivities of 134 Cs and 137 Cs decreased drastically only during the period of Asian Dust. And also, it was found that this trend was very similar to the atmospheric elemental concentration (ng×m -3 ) variation of stable cesium ( 133 Cs) quantified by elemental analyses using our developed ICP-DRC-MS instrument

Change of iron species and iron solubility in Asian dust during the long-range transport from western China to Japan

Directory of Open Access Journals (Sweden)

Y. Takahashi

2011-11-01

Full Text Available In the North Pacific, transport and deposition of mineral dust from Asia appear to be one of major sources of iron which can regulate growth of phytoplankton in the ocean. In this process, it is essential to identify chemical species of iron contained in Asian dust, because bioavailability of iron in the ocean is strongly influenced by the solubility of iron, which in turn is dependent on iron species in the dust. Here, we report that clay minerals (illite and chlorite in the dusts near the source collected at Aksu (western China can be transformed into ferrihydrite by atmospheric chemical processes during their long-range transport to eastern China (Qingdao and Japan (Tsukuba based on the speciation by X-ray absorption fine structure (XAFS and other methods such as X-ray diffraction and chemical extraction. As a result, Fe molar ratio in Aksu (illite : chlorite : ferrihydrite = 70 : 25 : 5 was changed to that in Tsukuba (illite : chlorite : ferrihydrite = 65 : 10 : 25. Moreover, leaching experiments were conducted to study the change of iron solubility. It was found that the iron solubility for the dust in Tsukuba (soluble iron fraction: 11.8 % and 1.10 % for synthetic rain water and seawater, respectively was larger than that in Aksu (4.1 % and 0.28 %, respectively, showing that iron in the dust after the transport becomes more soluble possibly due to the formation of ferrihydrite in the atmosphere. Our findings suggested that secondary formation of ferrihydrite during the transport should be considered as one of important processes in evaluating the supply of soluble iron to seawater.

Simulated variations of eolian dust from inner Asian deserts at the mid-Pliocene, last glacial maximum, and present day: contributions from the regional tectonic uplift and global climate change

Energy Technology Data Exchange (ETDEWEB)

Shi, Zhengguo; Liu, Xiaodong; An, Zhisheng [Chinese Academy of Sciences, State Key Laboratory of Loess Quaternary Geology (SKLLQG), Institute of Earth Environment, Xi' an (China); Yi, Bingqi; Yang, Ping [Texas A and M University, College Station, TX (United States); Mahowald, Natalie [Cornell University, Ithaca, NY (United States)

2011-12-15

Northern Tibetan Plateau uplift and global climate change are regarded as two important factors responsible for a remarkable increase in dust concentration originating from inner Asian deserts during the Pliocene-Pleistocene period. Dust cycles during the mid-Pliocene, last glacial maximum (LGM), and present day are simulated with a global climate model, based on reconstructed dust source scenarios, to evaluate the relative contributions of the two factors to the increment of dust sedimentation fluxes. In the focused downwind regions of the Chinese Loess Plateau/North Pacific, the model generally produces a light eolian dust mass accumulation rate (MAR) of 7.1/0.28 g/cm{sup 2}/kyr during the mid-Pliocene, a heavier MAR of 11.6/0.87 g/cm{sup 2}/kyr at present, and the heaviest MAR of 24.5/1.15 g/cm{sup 2}/kyr during the LGM. Our results are in good agreement with marine and terrestrial observations. These MAR increases can be attributed to both regional tectonic uplift and global climate change. Comparatively, the climatic factors, including the ice sheet and sea surface temperature changes, have modulated the regional surface wind field and controlled the intensity of sedimentation flux over the Loess Plateau. The impact of the Tibetan Plateau uplift, which increased the areas of inland deserts, is more important over the North Pacific. The dust MAR has been widely used in previous studies as an indicator of inland Asian aridity; however, based on the present results, the interpretation needs to be considered with greater caution that the MAR is actually not only controlled by the source areas but the surface wind velocity. (orig.)

Seasonal Contribution of Mineral Dust and Otlher Major Components to Particulate Matter at Two Remote Sites in Central Asia

Science.gov (United States)

Dust storms are significant contributors to ambient levels of particulate matter (PM) in many areas of the world. Central Asia, an area that is relatively understudied in this regard, is anticipated to be affected by dust storms due to its proximity to several major deserts that ...

Comparison of Key Absorption and Optical Properties Between Pure and Transported Anthropogenic Dust over East and Central Asia

Science.gov (United States)

Bi, Jianrong; Huang, Jianping; Holben, Brent N.; Zhang, Guolong

2016-01-01

Asian dust particulate is one of the primary aerosol constituents in the Earth-atmosphere system that exerts profound influences on environmental quality, human health, the marine biogeochemical cycle, and Earth's climate. To date, the absorptive capacity of dust aerosol generated from the Asian desert region is still an open question. In this article, we compile columnar key absorption and optical properties of mineral dust over East and Central Asian areas by utilizing the multiyear quality-assured datasets observed at 13 sites of the Aerosol Robotic Network (AERONET). We identify two types of Asian dust according to threshold criteria from previously published literature. (1) The particles with high aerosol optical depth at 440 nm (AOD(440) > or = 0.4) and a low Angstrom wavelength exponent at 440-870 nm (alpha or = 0.4 and 0.2 < alpha < 0.6 are designated as Transported Anthropogenic Dust (TDU), which is mainly dominated by dust aerosol and might mix with other anthropogenic aerosol types. Our results reveal that the primary components of high AOD days are predominantly dust over East and Central Asian regions, even if their variations rely on different sources, distance from the source, emission mechanisms, and meteorological characteristics. The overall mean and standard deviation of single-scattering albedo, asymmetry factor, real part and imaginary part of complex refractive index at 550 nm for Asian PDU are 0.935 +/- 0.014, 0.742 +/- 0.008, 1.526 +/- 0.029, and 0.00226 +/- 0.00056, respectively, while corresponding values are 0.921 +/- 0.021, 0.723 +/- 0.009, 1.521 +/- 0.025, and 0.00364 +/- 0.0014 for Asian TDU. Aerosol shortwave direct radiative effects at the top of the atmosphere (TOA), at the surface (SFC), and in the atmospheric layer (ATM) for Asian PDU (alpha < 0.2) and TDU (0.2 < alpha < 0.6) computed in this study, are a factor of 2 smaller than the results of Optical Properties of Aerosols and Clouds (OPAC) mineral-accumulated (mineral-acc.) and

Using NASA EOS in the Arabian and Saharan Deserts to Examine Dust Particle Size and Spectral Signature of Aerosols

Science.gov (United States)

Brenton, J. C.; Keeton, T.; Barrick, B.; Cowart, K.; Cooksey, K.; Florence, V.; Herdy, C.; Luvall, J. C.; Vasquez, S.

2012-12-01

Exposure to high concentrations of airborne particulate matter can have adverse effects on the human respiratory system. Ground-based studies conducted in Iraq have revealed the presence of potential human pathogens in airborne dust. According to the Environmental Protection Agency (EPA), airborne particulate matter below 2.5μm (PM2.5) can cause long-term damage to the human respiratory system. Given the relatively high incidence of new-onset respiratory disorders experienced by US service members deployed to Iraq, this research offers a new glimpse into how satellite remote sensing can be applied to questions related to human health. NASA's Earth Observing System (EOS) can be used to determine spectral characteristics of dust particles, the depth of dust plumes, as well as dust particle sizes. Comparing dust particle size from the Sahara and Arabian Deserts gives insight into the composition and atmospheric transport characteristics of dust from each desert. With the use of NASA SeaWiFS DeepBlue Aerosol, dust particle sizes were estimated using Angström exponent. Brightness Temperature Difference (BTD) equation was used to determine the distribution of particle sizes, the area of the dust storm, and whether silicate minerals were present in the dust. The Moderate-resolution Imaging Spectroradiometer (MODIS) on Terra satellite was utilized in calculating BTD. Minimal research has been conducted on the spectral characteristics of airborne dust in the Arabian and Sahara Deserts. Mineral composition of a dust storm that occurred 17 April 2008 near Baghdad was determined using imaging spectrometer data from the Jet Propulsion Laboratory Spectral Library and EO-1 Hyperion data. Mineralogy of this dust storm was subsequently compared to that of a dust storm that occurred over the Bodélé Depression in the Sahara Desert on 7 June 2003.

Effect of ecological restoration programs on dust concentrations in the North China Plain: a case study

Science.gov (United States)

Long, Xin; Tie, Xuexi; Li, Guohui; Cao, Junji; Feng, Tian; Zhao, Shuyu; Xing, Li; An, Zhisheng

2018-05-01

In recent decades, the Chinese government has made a great effort in initiating large-scale ecological restoration programs (ERPs) to reduce the dust concentrations in China, especially for dust storm episodes. Using the Moderate Resolution Imaging Spectroradiometer (MODIS) land cover product, the ERP-induced land cover changes are quantitatively evaluated in this study. Two obvious vegetation protective barriers arise throughout China from the southwest to the northeast, which are well known as the Green Great Wall (GGW). Both the grass GGW and forest GGW are located between the dust source region (DSR) and the densely populated North China Plain (NCP). To assess the effect of ERPs on dust concentrations, a regional transport/dust model (WRF-DUST, Weather Research and Forecast model with dust) is applied to investigate the evolution of dust plumes during a strong dust storm episode from 2 to 8 March 2016. The WRF-DUST model generally performs reasonably well in reproducing the temporal variations and spatial distributions of near-surface [PMC] (mass concentration of particulate matter with aerodynamic diameter between 2.5 and 10 µm) during the dust storm event. Sensitivity experiments have indicated that the ERP-induced GGWs help to reduce the dust concentration in the NCP, especially in BTH (Beijing, Tianjin, and Hebei). When the dust storm is transported from the upwind DSR to the downwind NCP, the [PMC] reduction ranges from -5 to -15 % in the NCP, with a maximum reduction of -12.4 % (-19.2 µg m-3) in BTH and -7.6 % (-10.1 µg m-3) in the NCP. We find the dust plumes move up to the upper atmosphere and are transported from the upwind DSR to the downwind NCP, accompanied by dust decrease. During the episode, the forest GGW is nonsignificant in dust concentration control because it is of benefit for dry deposition and not for emission. Conversely, the grass GGW is beneficial in controlling dust erosion and is the dominant reason for [PMC] decrease in the NCP

Effect of ecological restoration programs on dust concentrations in the North China Plain: a case study

Directory of Open Access Journals (Sweden)

X. Long

2018-05-01

Full Text Available In recent decades, the Chinese government has made a great effort in initiating large-scale ecological restoration programs (ERPs to reduce the dust concentrations in China, especially for dust storm episodes. Using the Moderate Resolution Imaging Spectroradiometer (MODIS land cover product, the ERP-induced land cover changes are quantitatively evaluated in this study. Two obvious vegetation protective barriers arise throughout China from the southwest to the northeast, which are well known as the Green Great Wall (GGW. Both the grass GGW and forest GGW are located between the dust source region (DSR and the densely populated North China Plain (NCP. To assess the effect of ERPs on dust concentrations, a regional transport/dust model (WRF-DUST, Weather Research and Forecast model with dust is applied to investigate the evolution of dust plumes during a strong dust storm episode from 2 to 8 March 2016. The WRF-DUST model generally performs reasonably well in reproducing the temporal variations and spatial distributions of near-surface [PMC] (mass concentration of particulate matter with aerodynamic diameter between 2.5 and 10 µm during the dust storm event. Sensitivity experiments have indicated that the ERP-induced GGWs help to reduce the dust concentration in the NCP, especially in BTH (Beijing, Tianjin, and Hebei. When the dust storm is transported from the upwind DSR to the downwind NCP, the [PMC] reduction ranges from −5 to −15 % in the NCP, with a maximum reduction of −12.4 % (−19.2 µg m−3 in BTH and −7.6 % (−10.1 µg m−3 in the NCP. We find the dust plumes move up to the upper atmosphere and are transported from the upwind DSR to the downwind NCP, accompanied by dust decrease. During the episode, the forest GGW is nonsignificant in dust concentration control because it is of benefit for dry deposition and not for emission. Conversely, the grass GGW is beneficial in controlling dust erosion and is the

The Continuous Monitoring of Desert Dust using an Infrared-based Dust Detection and Retrieval Method

Science.gov (United States)

Duda, David P.; Minnis, Patrick; Trepte, Qing; Sun-Mack, Sunny

2006-01-01

Airborne dust and sand are significant aerosol sources that can impact the atmospheric and surface radiation budgets. Because airborne dust affects visibility and air quality, it is desirable to monitor the location and concentrations of this aerosol for transportation and public health. Although aerosol retrievals have been derived for many years using visible and near-infrared reflectance measurements from satellites, the detection and quantification of dust from these channels is problematic over bright surfaces, or when dust concentrations are large. In addition, aerosol retrievals from polar orbiting satellites lack the ability to monitor the progression and sources of dust storms. As a complement to current aerosol dust retrieval algorithms, multi-spectral thermal infrared (8-12 micron) data from the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Meteosat-8 Spinning Enhanced Visible and Infrared Imager (SEVIRI) are used in the development of a prototype dust detection method and dust property retrieval that can monitor the progress of Saharan dust fields continuously, both night and day. The dust detection method is incorporated into the processing of CERES (Clouds and the Earth s Radiant Energy System) aerosol retrievals to produce dust property retrievals. Both MODIS (from Terra and Aqua) and SEVERI data are used to develop the method.

Investigation of dust formations in the atmosphere on the basis of satellite observations

Science.gov (United States)

Ivanchik, M. V.; Kliushnikov, S. I.; Krovotyntsev, V. A.; Serebrennikov, A. N.

1984-06-01

A method for the computer processing of space photographs is described which makes it possible to determine dust formations in the atmosphere. Dust formations are identified according to the character of contrast-density distribution. Processed images are compared with actinometric data collected in a dust storm area (Conakry, Guinea, May 1983).

Properties and effects of dust particles suspended in the martian atmosphere

International Nuclear Information System (INIS)

Pollack, J.B.; Colburn, D.S.; Flasar, M.; Kahn, R.; Carlston, C.E.; Pidek, D.

1979-01-01

Direct measurements of the optical depth above the two Viking landers are reported for a period of covering the summer, fall, and winter seasons in the northern hemisphere, a time period during which two global dust storms occurred. The optical depth had a value of about 1 just before the onset of each storm; it increased very rapidly, on a time scale of a few days, to peak values of about 3 and 6 with the arrival of the first and second storms, respectively; and its steadily decreased shortly thereafter (> or approx. = few days to few weeks) for both storms, with the decay occurring more rapidly during the initial period of decay. We have also carried out further analyses of observations of the sky brightness made with the lander cameras during the summer season to obtain improved estimates of other dust particle parameters, including the cross section weighted mean particle radius, several shape factors, and the imaginary indices of refraction. These results have been used to define the radiative properties of the suspended dust particles at solar wavelenths. The derived radiative properties of the dust were incorporated into a 1D radiative convective model. Satisfactory agreement with the temperature structure determined during the descent of the landers to the surface. Is achieved when allowance is made for the effects of vertical motions induced by large scale atmospheric dynamics. The diurnal temperature variations predicted by the 1D calculations for the observed optical depths are also in crude agreement with values inferred from orbiter and lander measurements. The 1D model predicts that the diurnal temperature change and daily mean temperature, averaged over the entire atmospheric vertical column, steadily increase as the optical depth of the dust increases to a value of several, and then subsequently change little

Impact of air pollution on deposition of mineral dust: Implications for ocean productivity

Science.gov (United States)

Fan, S.; Horrowitz, L. W.; Levy, H.; Moxim, W. J.

2003-12-01

Atmospheric dust aerosols originating from arid regions are simulated in an atmospheric global chemical transport model. Based on model results and observations of dust oncentration, we hypothesize that Asian dust over the North Pacific is mostly hydrophilic and removed efficiently by both ice and droplet nucleation processes. By contrast, African dust over the tropical Atlantic is mostly hydrophobic and removed by ice, but not droplet, nucleation. We suggest that Asian dust is transformed into hydrophilic aerosols by chemical reactions with air pollutants over East Asia, which produce high levels of readily soluble materials on the surface of dust particles. A model of chemical aging will be presented for the hygroscopic transformation of mineral dust in the atmosphere. The model predicts that evolving air pollution in East Asia could have caused an increase of dust deposition to the coastal oceans off Asia and a decrease by as much as 50 percent in the eastern North Pacific. Insofar as iron from dust deposition fuels diatom blooms in the North Pacific Ocean, this decrease could have potential consequences on ocean biology.

Iron content and solubility in dust from high-alpine snow along a north-south transect of High Asia

Directory of Open Access Journals (Sweden)

Guangjian Wu

2012-04-01

Full Text Available This study describes the dissolved and insoluble iron fraction of dust (mineral aerosol in high-alpine snow samples collected along a north-south transect across High Asia (Eastern Tien Shan, Qilian Shan, and Southern Tibetan Plateau. This dust provides the basic chemical properties of mid- and high-level tropospheric Asian dust that can supply the limiting iron nutrient for phytoplankton growth in the North Pacific. The iron content in Asian dust averages 4.95% in Eastern Tien Shan, 3.38–5.41% along Qilian Shan and 3.85% in the Southern Tibetan Plateau. The iron fractional solubility averages about 0.25% in Eastern Tien Shan, 0.05–2% along Qilian Shan and 1.5% in the Southern Tibetan Plateau. Among the controlling factors that can affect iron solubility in Asian dust, such as dust composition and particle grain size, acidity seems to be the most significant and can increase the iron solubility by one or two orders of magnitude with acidification of pH=0.66. Our results reveal that iron solubility of dust in the remote downwind sites is higher than that in high-alpine snow, confirming the strong pH-dependence of iron solubility, and indicating that Asian dust shows a large variation in iron solubility on a regional scale.

Simulating southwestern U.S. desert dust influences on supercell thunderstorms

Science.gov (United States)

Lerach, David G.; Cotton, William R.

2018-05-01

Three-dimensional numerical simulations were performed to evaluate potential southwestern U.S. dust indirect microphysical and direct radiative impacts on a real severe storms outbreak. Increased solar absorption within the dust plume led to modest increases in pre-storm atmospheric stability at low levels, resulting in weaker convective updrafts and less widespread precipitation. Dust microphysical impacts on convection were minor in comparison, due in part to the lofted dust concentrations being relatively few in number when compared to the background (non-dust) aerosol population. While dust preferentially serving as cloud condensation nuclei (CCN) versus giant CCN had opposing effects on warm rain production, both scenarios resulted in ample supercooled water and subsequent glaciation aloft, yielding larger graupel and hail. Associated latent heating from condensation and freezing contributed little to overall updraft invigoration. With reduced rain production overall, the simulations that included dust effects experienced slightly reduced grid-cumulative precipitation and notably warmer and spatially smaller cold pools. Dust serving as ice nucleating particles did not appear to play a significant role. The presence of dust ultimately reduced the number of supercells produced but allowed for supercell evolution characterized by consistently higher values of relative vertical vorticity within simulated mesocyclones. Dust radiative and microphysical effects were relatively small in magnitude when compared to those from altering the background convective available potential energy and vertical wind shear. It is difficult to generalize such findings from a single event, however, due to a number of case-specific environmental factors. These include the nature of the low-level moisture advection and characteristics of the background aerosol distribution.

Asian sand dust enhances ovalbumin-induced eosinophil recruitment in the alveoli and airway of mice

International Nuclear Information System (INIS)

Hiyoshi, Kyoko; Ichinose, Takamichi; Sadakane, Kaori; Takano, Hirohisa; Nishikawa, Masataka; Mori, Ikuko; Yanagisawa, Rie; Yoshida, Seiichi; Kumagai, Yoshito; Tomura, Shigeo; Shibamoto, Takayuki

2005-01-01

Asian sand dust (ASD) containing sulfate (SO 4 2- ) reportedly causes adverse respiratory health effects but there is no experimental study showing the effect of ASD toward allergic respiratory diseases. The effects of ASD and ASD plus SO 4 2- toward allergic lung inflammation induced by ovalbumin (OVA) were investigated in this study. ICR mice were administered intratracheally with saline; ASD alone (sample from Shapotou desert); and ASD plus SO 4 2- (ASD-SO 4 ); OVA+ASD; OVA+ASD-SO 4 . ASD or ASD-SO 4 alone caused mild nutrophilic inflammation in the bronchi and alveoli. ASD and ASD-SO 4 increased pro-inflammatory mediators, such as Keratinocyte chemoattractant (KC) and macrophage inflammatory protein (MIP)-1 alpha, in bronchoalveolar lavage fluids (BALF). ASD and ASD-SO 4 enhanced eosinophil recruitment induced by OVA in the alveoli and in the submucosa of the airway, which has a goblet cell proliferation in the bronchial epithelium. However, a further increase of eosinophils by addition of SO 4 2- was not observed. The two sand dusts synergistically increased interleukin-5 (IL-5) and monocyte chemotactic protein-1 (MCP-1), which were associated with OVA, in BALF. However, the increased levels of IL-5 were lower in the OVA+ASD-SO 4 group than in the OVA+ASD group. ASD caused the adjuvant effects to specific-IgG1 production by OVA, but not to specific-IgE. These results suggest that the enhancement of eosinophil recruitment in the lung is mediated by synergistically increased IL-5 and MCP-1. IgG1 antibodies may play an important role in the enhancement of allergic reaction caused by OVA and sand dust. However, extra sulfate may not contribute to an increase of eosinophils

Iron content and solubility in dust from high-alpine snow along a north-south transect of High Asia

OpenAIRE

Wu, Guangjian; Zhang, Chenglong; Li, Zhongqin; Zhang, Xuelei; Gao, Shaopeng

2012-01-01

This study describes the dissolved and insoluble iron fraction of dust (mineral aerosol) in high-alpine snow samples collected along a north-south transect across High Asia (Eastern Tien Shan, Qilian Shan, and Southern Tibetan Plateau). This dust provides the basic chemical properties of mid- and high-level tropospheric Asian dust that can supply the limiting iron nutrient for phytoplankton growth in the North Pacific. The iron content in Asian dust averages 4.95% in Eastern Tien Shan, 3.38–5...

Correlation between Asian Dust and Specific Radioactivities of Fission Products Included in Airborne Samples in Tokushima, Shikoku Island, Japan, Due to the Fukushima Nuclear Accident

Energy Technology Data Exchange (ETDEWEB)

Sakama, M., E-mail: minorusakama@tokushima-u.ac.jp [Department of Radiological Science, Division of Biomedical Information Sciences, Institute of Health Biosciences, The University of Tokushima, Tokushima 770-8509 (Japan); Nagano, Y. [Department of Radiological Science, Division of Biomedical Information Sciences, Institute of Health Biosciences, The University of Tokushima, Tokushima 770-8509 (Japan); Kitade, T. [Department of Laboratory, M and S Instruments Inc., Osaka 532-0005 (Japan); Shikino, O. [Department of Inorganic Analysis, PerkinElmer Japan Co. Ltd., Yokohama 240-0005 (Japan); Nakayama, S. [Department of Nuclear Science, Institute of Socio-Arts and Sciences, The University of Tokushima, Tokushima 770-8502 (Japan)

2014-06-15

Radioactive fission product {sup 131}I released from the Fukushima Daiichi Nuclear Power Plants (FD-NPP) was first detected on March 23, 2011 in an airborne aerosol sample collected at Tokushima, Shikoku Island, located in western Japan. Two other radioactive fission products, {sup 134}Cs and {sup 137}Cs were also observed in a sample collected from April 2 to 4, 2011. The maximum specific radioactivities observed in this work were about 2.5 to 3.5 mBq×m{sup -3} in a airborne aerosol sample collected on April 6. During the course of the continuous monitoring, we also made our first observation of seasonal Asian Dust and those fission products associated with the FDNPP accident concurrently from May 2 to 5, 2011. We found that the specific radioactivities of {sup 134}Cs and {sup 137}Cs decreased drastically only during the period of Asian Dust. And also, it was found that this trend was very similar to the atmospheric elemental concentration (ng×m{sup -3}) variation of stable cesium ({sup 133}Cs) quantified by elemental analyses using our developed ICP-DRC-MS instrument.

Development of electrochemical biosensor for detection of pathogenic microorganism in Asian dust events.

Science.gov (United States)

Yoo, Min-Sang; Shin, Minguk; Kim, Younghun; Jang, Min; Choi, Yoon-E; Park, Si Jae; Choi, Jonghoon; Lee, Jinyoung; Park, Chulhwan

2017-05-01

We developed a single-walled carbon nanotubes (SWCNTs)-based electrochemical biosensor for the detection of Bacillus subtilis, one of the microorganisms observed in Asian dust events, which causes respiratory diseases such as asthma and pneumonia. SWCNTs plays the role of a transducer in biological antigen/antibody reaction for the electrical signal while 1-pyrenebutanoic acid succinimidyl ester (1-PBSE) and ant-B. subtilis were performed as a chemical linker and an acceptor, respectively, for the adhesion of target microorganism in the developed biosensor. The detection range (10 2 -10 10  CFU/mL) and the detection limit (10 2  CFU/mL) of the developed biosensor were identified while the response time was 10 min. The amount of target B. subtilis was the highest in the specificity test of the developed biosensor, compared with the other tested microorganisms (Staphylococcus aureus, Flavobacterium psychrolimnae, and Aquabacterium commune). In addition, target B. subtilis detected by the developed biosensor was observed by scanning electron microscope (SEM) analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dust: Small-scale processes with global consequences

Science.gov (United States)

Okin, G.S.; Bullard, J.E.; Reynolds, R.L.; Ballantine, J.-A.C.; Schepanski, K.; Todd, M.C.; Belnap, J.; Baddock, M.C.; Gill, T.E.; Miller, M.E.

2011-01-01

Desert dust, both modern and ancient, is a critical component of the Earth system. Atmospheric dust has important effects on climate by changing the atmospheric radiation budget, while deposited dust influences biogeochemical cycles in the oceans and on land. Dust deposited on snow and ice decreases its albedo, allowing more light to be trapped at the surface, thus increasing the rate of melt and influencing energy budgets and river discharge. In the human realm, dust contributes to the transport of allergens and pathogens and when inhaled can cause or aggravate respiratory diseases. Dust storms also represent a significant hazard to road and air travel. Because it affects so many Earth processes, dust is studied from a variety of perspectives and at multiple scales, with various disciplines examining emissions for different purposes using disparate strategies. Thus, the range of objectives in studying dust, as well as experimental approaches and results, has not yet been systematically integrated. Key research questions surrounding the production and sources of dust could benefit from improved collaboration among different research communities. These questions involve the origins of dust, factors that influence dust production and emission, and methods through which dust can be monitored. ?? Author(s) 2011.

Fine-scale application of WRF-CAM5 during a dust storm episode over East Asia: Sensitivity to grid resolutions and aerosol activation parameterizations

Science.gov (United States)

Wang, Kai; Zhang, Yang; Zhang, Xin; Fan, Jiwen; Leung, L. Ruby; Zheng, Bo; Zhang, Qiang; He, Kebin

2018-03-01

An advanced online-coupled meteorology and chemistry model WRF-CAM5 has been applied to East Asia using triple-nested domains at different grid resolutions (i.e., 36-, 12-, and 4-km) to simulate a severe dust storm period in spring 2010. Analyses are performed to evaluate the model performance and investigate model sensitivity to different horizontal grid sizes and aerosol activation parameterizations and to examine aerosol-cloud interactions and their impacts on the air quality. A comprehensive model evaluation of the baseline simulations using the default Abdul-Razzak and Ghan (AG) aerosol activation scheme shows that the model can well predict major meteorological variables such as 2-m temperature (T2), water vapor mixing ratio (Q2), 10-m wind speed (WS10) and wind direction (WD10), and shortwave and longwave radiation across different resolutions with domain-average normalized mean biases typically within ±15%. The baseline simulations also show moderate biases for precipitation and moderate-to-large underpredictions for other major variables associated with aerosol-cloud interactions such as cloud droplet number concentration (CDNC), cloud optical thickness (COT), and cloud liquid water path (LWP) due to uncertainties or limitations in the aerosol-cloud treatments. The model performance is sensitive to grid resolutions, especially for surface meteorological variables such as T2, Q2, WS10, and WD10, with the performance generally improving at finer grid resolutions for those variables. Comparison of the sensitivity simulations with an alternative (i.e., the Fountoukis and Nenes (FN) series scheme) and the default (i.e., AG scheme) aerosol activation scheme shows that the former predicts larger values for cloud variables such as CDNC and COT across all grid resolutions and improves the overall domain-average model performance for many cloud/radiation variables and precipitation. Sensitivity simulations using the FN series scheme also have large impacts on

Dust observations by PFS on Mars Express

Science.gov (United States)

Zasova, L. V.; Formisano, V.; Moroz, V. I.; Grassi, D.; Ignatiev, N. I.; Blecka, M. I.; Maturilli, A.; Palomba, E.; Piccioni, G.; Pfs Team

Dust is always present in the Martian atmosphere with opacity, which changes from values below 0.1 (at 9 μ m) up to several units during the dust storms. From the thermal IR (LW channel of PFS) the dust opacity is retrieved in a self consistent way together with the temperature profile from the same spectrum A preliminary investigation along the orbit, which comes through Hellas, shows that the value of dust opacity anticorrelates with surface altitude. From -70 to +25 of latitude the vertical dust distribution follows the exponential low with the scale of 12 km, which corresponds to the gaseous scale height near noon and indicates for well mixed condition. The dust opacity, corresponding to the zero surface altitude, is found of 0.25+-0.05. More detailed investigations of all available data will be presented, including analysis of both short- and long- wavelength spectra of PFS.

Biological response to coastal upwelling and dust deposition in the area off Northwest Africa

Science.gov (United States)

Ohde, T.; Siegel, H.

2010-05-01

Nutrient supply in the area off Northwest Africa is mainly regulated by two processes, coastal upwelling and deposition of Saharan dust. In the present study, both processes were analyzed and evaluated by different methods, including cross-correlation, multiple correlation, and event statistics, using remotely sensed proxies of the period from 2000 to 2008 to investigate their influence on the marine environment. The remotely sensed chlorophyll- a concentration was used as a proxy for the phytoplankton biomass stimulated by nutrient supply into the euphotic zone from deeper water layers and from the atmosphere. Satellite-derived alongshore wind stress and sea-surface temperature were applied as proxies for the strength and reflection of coastal upwelling processes. The westward wind and the dust component of the aerosol optical depth describe the transport direction of atmospheric dust and the atmospheric dust column load. Alongshore wind stress and induced upwelling processes were most significantly responsible for the surface chlorophyll- a variability, accounting for about 24% of the total variance, mainly in the winter and spring due to the strong north-easterly trade winds. The remotely sensed proxies allowed determination of time lags between biological response and its forcing processes. A delay of up to 16 days in the surface chlorophyll- a concentration due to the alongshore wind stress was determined in the northern winter and spring. Although input of atmospheric iron by dust storms can stimulate new phytoplankton production in the study area, only 5% of the surface chlorophyll- a variability could be ascribed to the dust component in the aerosol optical depth. All strong desert storms were identified by an event statistics in the time period from 2000 to 2008. The 57 strong storms were studied in relation to their biological response. Six events were clearly detected in which an increase of chlorophyll- a was caused by Saharan dust input and not by

Synergistic Use of Remote Sensing and Modeling for Tracing Dust Storms in the Mediterranean

Directory of Open Access Journals (Sweden)

D. G. Kaskaoutis

2012-01-01

Full Text Available This study focuses on the detection of the dust source region and monitoring of the transport of the dust plume from its primary outflow to final deposition. The application area is the Sahara desert and the eastern Mediterranean, where two dust events occurred during the period 4–6 February 2009, an unusual event for a winter period. The Aqua-MODIS and OMI observations clearly define the spatial distribution of the dust plumes, while the CALIPSO observations of total attenuated backscatter (TAB at 532 nm, depolarization ratio (DR, and attenuated color ratio (1064/532 nm on 5 February 2009 provide a clear view and vertical structure of the dust-laden layer. The dust source region is defined to be near the Chad-Niger-Libyan borders, using satellite observations and model (DREAM output. This dust plume is vertically extended up to 2.5 km and is observed as a mass plume of dust from surface level to that altitude, where the vertical variation of TAB (0.002 to 0.2 and DR (0.2–0.5 implies dust-laden layer with non-spherical particles. CALIPSO profiles show that after the dust plume reached at its highest level, the dust particles start to be deposited over the Mediterranean and the initial dust plume was strongly attenuated, while features of dust were limited below about 1–1.5 km for latitudes northern of ~36° (Greek territory.

I Got Them Dust Bowl Blues: Wind Erosion in the Music of the Southern Great Plains

Science.gov (United States)

Lee, J. A.

2017-12-01

This paper deals with the role of wind erosion and blowing dust on the music of the Dust Bowl region, a portion of the southern Great Plains of the United States. A defining characteristic of the region is dust storms, and in the 1930s, severe dust storms created dramatic images that came to symbolize all of the economic, social and environmental hardships suffered by the people during the 1930s. The music of the time, by Woody Guthrie and others, suggested that the region was being destroyed, never to recover. The region was resilient, however, and in recent decades, dust has been depicted in songs either as an adversity to be endured or simply as a normal part of life in the area. It may be that blowing dust has become a defining characteristic of the region because of a somewhat warped sense of pride in living in an often-difficult environment.

Exploring Dust Impacts on Tropical Systems from the NASA HS-3 Field Campaign

Science.gov (United States)

Nowottnick, Ed; Colarco, Pete; da Silva, Arlindo; Barahona, Donifan; Hlavka, Dennis

2015-01-01

One of the overall scientific goals of the NASA Hurricane and Severe Storm Sentinel (HS-3) field campaign is to better understand the role of the Saharan Air Layer (SAL) in tropical storm development. During the 2012 HS-3 deployment, the Cloud Physics Lidar (CPL) observed dust within SAL air in close proximity to a developing Nadine (September 11, 2012). Throughout the mission, the NASA GEOS-5 modeling system supported HS-3 by providing 0.25 degrees resolution 5-day global forecasts of aerosols, which were used to support mission planning. The aerosol module was radiatively interactive within the GEOS-5 model, but aerosols were not directly coupled to cloud and precipitation processes. In this study we revisit the aerosol forecasts with an updated version of the GEOS-5 model. For the duration of Hurricane Nadine, we run multiday climate simulations leading up to each respective Global Hawk flight with and without aerosol direct interaction. For each set of simulations, we compare simulated dust mass fluxes to identify differences in SAL entrainment related to the interaction between dust aerosols and the atmosphere. We find that the direct effects of dust induce a low level anticyclonic circulation that temporarily shields Nadine from the intrusion of dry air, leading to a more intense storm.

Biological effects of desert dust in respiratory epithelial cells and a murine model.

Science.gov (United States)

Abstract As a result of the challenge of recent dust storms to public health, we tested the postulate that desert dust collected in the southwestern United States could impact a biological effect in respiratory epithelial cells and an animal model. Two samples of surface sedime...

Long-term dust aerosol production from natural sources in Iceland.

Science.gov (United States)

Dagsson-Waldhauserova, Pavla; Arnalds, Olafur; Olafsson, Haraldur

2017-02-01

Iceland is a volcanic island in the North Atlantic Ocean with maritime climate. In spite of moist climate, large areas are with limited vegetation cover where >40% of Iceland is classified with considerable to very severe erosion and 21% of Iceland is volcanic sandy deserts. Not only do natural emissions from these sources influenced by strong winds affect regional air quality in Iceland ("Reykjavik haze"), but dust particles are transported over the Atlantic ocean and Arctic Ocean >1000 km at times. The aim of this paper is to place Icelandic dust production area into international perspective, present long-term frequency of dust storm events in northeast Iceland, and estimate dust aerosol concentrations during reported dust events. Meteorological observations with dust presence codes and related visibility were used to identify the frequency and the long-term changes in dust production in northeast Iceland. There were annually 16.4 days on average with reported dust observations on weather stations within the northeastern erosion area, indicating extreme dust plume activity and erosion within the northeastern deserts, even though the area is covered with snow during the major part of winter. During the 2000s the highest occurrence of dust events in six decades was reported. We have measured saltation and Aeolian transport during dust/volcanic ash storms in Iceland, which give some of the most intense wind erosion events ever measured. Icelandic dust affects the ecosystems over much of Iceland and causes regional haze. It is likely to affect the ecosystems of the oceans around Iceland, and it brings dust that lowers the albedo of the Icelandic glaciers, increasing melt-off due to global warming. The study indicates that Icelandic dust may contribute to the Arctic air pollution. Long-term records of meteorological dust observations from Northeast Iceland indicate the frequency of dust events from Icelandic deserts. The research involves a 60-year period and

Radiocarbon analysis of BC and OC in PM10 aerosols at Cape Hedo, Okinawa, Japan, during long-range transport events from East Asian countries

International Nuclear Information System (INIS)

Handa, Daishi; Nakajima, Hitomi; Arakaki, Takemitsu; Kumata, Hidetoshi; Shibata, Yasuyuki; Uchida, Masao

2010-01-01

We determined the 14 C/ 12 C ratio and concentrations of black carbon (BC) and organic carbon (OC) in airborne particulate matter (APM) with diameter 10 ) collected in Okinawa, Japan, between March and June 2008. During Asian dust events in March and April, APM and OC concentrations in PM 10 aerosols were approximately threefold and twofold higher than those during the non-Asian-dust period in June. 'Refractory' BC concentrations (i.e., because of refraction, 10 aerosols collected during the Asian dust events (mean = 41.5% and 62.3%, respectively) than for those collected in the non-Asian-dust period (mean = 67.2% and 93.8%, respectively), indicating a strong influence of fossil-fuel-derived carbon during Asian dust events. One sample showed high OC concentration but relatively low BC concentration, suggesting formation during the long-range transport of biogenic organic compounds. The results suggest that not only fossil-fuel-derived air pollutants but also organic compounds derived from biomass in Asia should be considered to better characterize long-range transported aerosols.

Regional and climatic controls on seasonal dust deposition in the southwestern U.S.

Science.gov (United States)

Reheis, M.C.; Urban, F.E.

2011-01-01

Vertical dust deposition rates (dust flux) are a complex response to the interaction of seasonal precipitation, wind, changes in plant cover and land use, dust source type, and local vs. distant dust emission in the southwestern U.S. Seasonal dust flux in the Mojave-southern Great Basin (MSGB) deserts, measured from 1999 to 2008, is similar in summer-fall and winter-spring, and antecedent precipitation tends to suppress dust flux in winter-spring. In contrast, dust flux in the eastern Colorado Plateau (ECP) region is much larger in summer-fall than in winter-spring, and twice as large as in the MSGB. ECP dust is related to wind speed, and in the winter-spring to antecedent moisture. Higher summer dust flux in the ECP is likely due to gustier winds and runoff during monsoonal storms when temperature is also higher. Source types in the MSGB and land use in the ECP have important effects on seasonal dust flux. In the MSGB, wet playas produce salt-rich dust during wetter seasons, whereas antecedent and current moisture suppress dust emission from alluvial and dry-playa sources during winter-spring. In the ECP under drought conditions, dust flux at a grazed-and-plowed site increased greatly, and also increased at three annualized, previously grazed sites. Dust fluxes remained relatively consistent at ungrazed and currently grazed sites that have maintained perennial vegetation cover. Under predicted scenarios of future climate change, these results suggest that an increase in summer storms may increase dust flux in both areas, but resultant effects will depend on source type, land use, and vegetation cover. ?? 2011.

A 12-year observation of water-soluble ions in TSP aerosols collected at a remote marine location in the western North Pacific: an outflow region of Asian dust

Science.gov (United States)

Boreddy, S. K. R.; Kawamura, K.

2015-06-01

In order to characterize the long-term trend of remote marine aerosols, a 12-year observation was conducted for water-soluble ions in TSP (total suspended particulate) aerosols collected from 2001 to 2012 in the Asian outflow region at Chichijima Island in the western North Pacific. We found a clear difference in chemical composition between the continentally affected and marine background air masses over the observation site. Asian continental air masses are delivered from late autumn to spring, whereas marine air masses were dominated in summer. Concentrations of non-sea salt (nss-) SO42-, NO3-, NH4+, nss-K+ and nss-Ca2+ are high in winter and spring and low in summer. On the other hand, MSA- (methanesulfonate) exhibits higher concentrations during spring and winter, probably due to springtime dust bloom or due to the direct continental transport of MSA- to the observation site. We could not find any clear decadal trend for Na+, Cl-, Mg2+ and nss-Ca2+ in all seasons, although there exists a clear seasonal trend. However, concentrations of nss-SO42- continuously decreased from 2007 to 2012, probably due to the decreased SO2 emissions in East Asia especially in China. In contrast, nss-K+ and MSA- concentrations continuously increased from 2001 to 2012 during winter and spring seasons, demonstrating that biomass burning and/or terrestrial biological emissions in East Asia are being increasingly transported from the Asian continent to the western North Pacific. This study also demonstrates that Asian dusts can act as an important source of nutrients for phytoplankton and thus sea-to-air emission of dimethyl sulfide over the western North Pacific.

Dust emission: small-scale processes with global consequences

Science.gov (United States)

Okin, Gregory S.; Bullard, Joanna E.; Reynolds, Richard L.; Ballantine, John-Andrew C.; Schepanski, Kerstin; Todd, Martin C.; Belnap, Jayne; Baddock, Matthew C.; Gill, Thomas E.; Miller, Mark E.

2011-01-01

Desert dust, both modern and ancient, is a critical component of the Earth system. Atmospheric dust has important effects on climate by changing the atmospheric radiation budget, while deposited dust influences biogeochemical cycles in the oceans and on land. Dust deposited on snow and ice decreases its albedo, allowing more light to be trapped at the surface, thus increasing the rate of melt and influencing energy budgets and river discharge. In the human realm, dust contributes to the transport of allergens and pathogens and when inhaled can cause or aggravate respiratory diseases. Dust storms also represent a significant hazard to road and air travel. Because it affects so many Earth processes, dust is studied from a variety of perspectives and at multiple scales, with various disciplines examining emissions for different purposes using disparate strategies. Thus, the range of objectives in studying dust, as well as experimental approaches and results, has not yet been systematically integrated. Key research questions surrounding the production and sources of dust could benefit from improved collaboration among different research communities. These questions involve the origins of dust, factors that influence dust production and emission, and methods through which dust can be monitored.

Spectral optical properties of long-range transport Asian dust and pollution aerosols over Northeast Asia in 2007 and 2008

Directory of Open Access Journals (Sweden)

J. Jung

2010-06-01

Full Text Available As a part of the IGAC (International Global Atmospheric Chemistry Mega-cities program, aerosol physical and optical properties were continuously measured from March 2007 to March 2008 at an urban site (37.57° N, 126.94° E in Seoul, Korea. Spectral optical properties of long-range transported Asian dust and pollution aerosols have been investigated based on the year long measurement data. Optically measured black carbon/thermally measured elemental carbon (BC/EC ratio showed clear monthly variation with high values in summer and low values in winter mainly due to the enhancement of light attenuation by the internal mixing of EC. Novel approach has been suggested to retrieve the spectral light absorption coefficient (b_abs from Aethalometer raw data by using BC/EC ratio. Mass absorption efficiency, σ_abs (=b_abs/EC at 550 nm was determined to be 9.0±1.3, 8.9±1.5, 9.5±2.0, and 10.3±1.7 m² g⁻¹ in spring, summer, fall, and winter, respectively with an annual mean of 9.4±1.8 m² g⁻¹. Threshold values to classify severe haze events were suggested in this study. Increasing trend of aerosol single scattering albedo (SSA with wavelength was observed during Asian dust events while little spectral dependence of SSA was observed during long-range transport pollution (LTP events. Satellite aerosol optical thickness (AOT and Hysplit air mass backward trajectory analyses as well as chemical analysis were performed to characterize the dependence of spectral optical properties on aerosol type. Results from this study can provide useful information for studies on regional air quality and aerosol's effects on climate change.

Stable carbon and nitrogen isotopic compositions of ambient aerosols collected from Okinawa Island in the western North Pacific Rim, an outflow region of Asian dusts and pollutants

Science.gov (United States)

Kunwar, Bhagawati; Kawamura, Kimitaka; Zhu, Chunmao

2016-04-01

Stable carbon (δ13C) and nitrogen (δ15N) isotope ratios were measured for total carbon (TC) and nitrogen (TN), respectively, in aerosol (TSP) samples collected at Cape Hedo, Okinawa, an outflow region of Asian pollutants, during 2009-2010. The averaged δ13C and δ15N ratios are -22.2‰ and +12.5‰, respectively. The δ13C values are similar in both spring (-22.5‰) and winter (-22.5‰), suggesting the similar sources and/or source regions. We found that δ13C from Okinawa aerosols are ca. 2‰ higher than those reported from Chinese megacities probably due to photochemical aging of organic aerosols. A strong correlation (r = 0.81) was found between nss-Ca and TSP, suggesting that springtime aerosols are influenced from Asian dusts. However, carbonates in the Asian dusts were titrated with acidic species such as sulfuric acid and oxalic acid during atmospheric transport although two samples suggested the presence of remaining carbonate. No correlations were found between δ13C and tracer compounds (levoglucosan, elemental carbon, oxalic acid, and Na+). During winter and spring, coal burning is significant source in China. Based on isotopic mass balance, contribution of coal burning origin particles to total aerosol carbon was estimated as ca. 97% in winter, which is probably associated with the high emissions in China. Contribution of NO3- to TN was on average 45% whereas that of NH4+ was 18%. These results suggest that vehicular exhaust is an important source of TN in Okinawa aerosols. Concentration of water-soluble organic nitrogen (WSON) is higher in summer, suggesting that WSON is more emitted from the ocean in warmer season whereas inorganic nitrogen is more emitted in winter and spring from pollution sources in the Asian continent.

Electrodynamic Dust Shield for Solar Panels on Mars

Science.gov (United States)

Calle, C. I.; Buhler, C. R.; Mantovani, J. G.; Clements S.; Chen, A.; Mazumder, M. K.; Biris, A. S.; Nowicki, A. W.

2004-01-01

The Materials Adherence Experiment on the Mars Pathfinder mission measured an obscuration of the solar arrays due to dust deposition at a rate of about 0.2 8% per day. It was estimated that settling dust may cause degradation in performance of a solar panel of between 22% and 89% over the course of two years [1, 2]. These results were obtained without the presence of a global dust storm. Several types of adherence forces keep dust particles attached to surfaces. The most widely discussed adherence force is the electrostatic force. Laboratory experiments [3] as well as indirect evidence from the Wheel Abrasion Experiment on Pathfinder [4] indicate that it is very likely that the particles suspended in the Martian atmosphere are electrostatically charged.

Red Dawn: Characterizing Iron Oxide Minerals in Atmospheric Dust

Science.gov (United States)

Yauk, K.; Ottenfeld, C. F.; Reynolds, R. L.; Goldstein, H.; Cattle, S.; Berquo, T. S.; Moskowitz, B. M.

2012-12-01

Atmospheric dust is comprised of many components including small amounts of iron oxide minerals. Although the iron oxides make up a small weight percent of the bulk dust, they are important because of their roles in ocean fertilization, controls on climate, and as a potential health hazard to humans. Here we report on the iron oxide mineralogy in dust from a large dust storm, dubbed Red Dawn, which engulfed eastern Australia along a 3000 km front on 23 September 2009. Red Dawn originated from the lower Lake Eyre Basin of South Australia, western New South Wales (NSW) and southwestern Queensland and was the worst dust storm to have hit the city of Sydney in more than 60 years. Dust samples were collected from various locations across eastern Australia (Lake Cowal, Orange, Hornsby, Sydney) following the Red Dawn event. Our dust collection provides a good opportunity to study the physical and mineralogical properties of iron oxides from Red Dawn using a combination of reflectance spectroscopy, Mössbauer spectroscopy (MB), and magnetic measurements. Magnetization measurements from 20-400 K reveal that magnetite/maghemite, hematite and goethite are present in all samples with magnetite occurring in trace amounts (effects (d< 100 nm). Finally, we compared reflectance with a magnetic parameter (hard isothermal remanent magnetization, HIRM) for ferric oxide abundance to assess the degree to which ferric oxide in these samples might absorb solar radiation. In samples for which both parameters were obtained, HIRM and average reflectance over the visible wavelengths are correlated as a group (r2=0.24). These results indicate that the ferric oxide minerals in Red Dawn dust absorb solar radiation. Much of this ferric oxide occurs likely as grain coatings of nanohematite and nanogoethite, thereby providing high surface area to enhance absorption of solar radiation.

Temporal and spatial variations in sand and dust storm events in East Asia from 2007 to 2016: Relationships with surface conditions and climate change.

Science.gov (United States)

An, Linchang; Che, Huizheng; Xue, Min; Zhang, Tianhang; Wang, Hong; Wang, Yaqiang; Zhou, Chunhong; Zhao, Hujia; Gui, Ke; Zheng, Yu; Sun, Tianze; Liang, Yuanxin; Sun, Enwei; Zhang, Hengde; Zhang, Xiaoye

2018-08-15

We analyzed the frequency and intensity of sand and dust storms (SDSs) in East Asia from 2007 to 2016 using observational data from ground stations, numerical modeling, and vegetation indices obtained from both satellite and reanalysis data. The relationships of SDSs with surface conditions and the synoptic circulation pattern were also analyzed. The statistical analyses demonstrated that the number and intensity of SDS events recorded in spring during 2007 to 2016 showed a decreasing trend. The total number of spring SDSs decreased from at least ten events per year before 2011 to less than ten events per year after 2011. The overall average annual variation of the surface dust concentration in the main dust source regions decreased 33.24μg/m 3 (-1.75%) annually. The variation in the temperatures near and below the ground surface and the amount of precipitation and soil moisture all favored an improvement in vegetation coverage, which reduced the intensity and frequency of SDSs. The strong winds accompanying the influx of cold air from high latitudes showed a decreasing trend, leading to a decrease in the number of SDSs and playing a key role in the decadal decrease of SDSs. The decrease in the intensity of the polar vortex during study period was closely related to the decrease in the intensity and frequency of SDSs. Copyright © 2018 Elsevier B.V. All rights reserved.

The DREAMS experiment flown on the ExoMars 2016 mission for the study of Martian environment during the dust storm season

Science.gov (United States)

Bettanini, C.; Esposito, R.; Debei, S.; Molfese, C.; Colombatti, G.; Aboudan, A.; Brucato, J. R.; Cortecchia, F.; Di Achille, G.; Guizzo, G. P.; Friso, E.; Ferri, F.; Marty, L.; Mennella, V.; Molinaro, R.; Schipani, P.; Silvestro, S.; Mugnuolo, R.; Pirrotta, S.; Marchetti, E.; Harri, A.-M.; Montmessin, F.; Wilson, C.; Arruego Rodriguez, I.; Abbaki, S.; Apestigue, V.; Bellucci, G.; Berthelier, J. J.; Calcutt, S. B.; Forget, F.; Genzer, M.; Gilbert, P.; Haukka, H.; Jimenez, J. J.; Jimenez, S.; Josset, J. L.; Karatekin, O.; Landis, G.; Lorenz, R.; Martinez, J.; Möhlmann, D.; Moirin, D.; Palomba, E.; Pateli, M.; Pommereau, J.-P.; Popa, C. I.; Rafkin, S.; Rannou, P.; Renno, N. O.; Schmidt, W.; Simoes, F.; Spiga, A.; Valero, F.; Vazquez, L.; Vivat, F.; Witasse, O.

2017-08-01

The DREAMS (Dust characterization, Risk assessment and Environment Analyser on the Martian Surface) experiment on Schiaparelli lander of ExoMars 2016 mission was an autonomous meteorological station designed to completely characterize the Martian atmosphere on surface, acquiring data not only on temperature, pressure, humidity, wind speed and direction, but also on solar irradiance, dust opacity and atmospheric electrification, to measure for the first time key parameters linked to hazard conditions for future manned explorations. Although with very limited mass and energy resources, DREAMS would be able to operate autonomously for at least two Martian days (sols) after landing in a very harsh environment as it was supposed to land on Mars during the dust storm season (October 2016 in Meridiani Planum) relying on its own power supply. ExoMars mission was successfully launched on 14th March 2016 and Schiaparelli entered the Mars atmosphere on October 20th beginning its 'six minutes of terror' journey to the surface. Unfortunately, some unexpected behavior during the parachuted descent caused an unrecoverable critical condition in navigation system of the lander driving to a destructive crash on the surface. The adverse sequence of events at 4 km altitude triggered the transition of the lander in surface operative mode, commanding switch on the DREAMS instrument, which was therefore able to correctly power on and send back housekeeping data. This proved the nominal performance of all DREAMS hardware before touchdown demonstrating the highest TRL of the unit for future missions. This paper describes this experiment in terms of scientific goals, design, performances, testing and operational capabilities with an overview of in flight performances and available mission data.

Correlation between Yellow Dust and Radioactivity

International Nuclear Information System (INIS)

AIZaabia, Mouza A; Kim, Byoung-Jik

2015-01-01

In East Asia, yellow dust or Asian Dust (AD) outbreaks are among the largest contributors of wind-blown dust that carry natural and anthropogenic radionuclides and subsequently alter their concentration and distribution throughout the environment. Although the Korean Peninsula has been experiencing AD events since ancient times, the research has tended to focus on the transport routes and characteristics of AD, rather than on its impact on radionuclide activity levels. This paper examines the relationship between radionuclide concentration in the air and the frequency of dusty days in South Korea during AD intrusion events. It also investigates whether increased radionuclide concentration is a function of either more mass or more dust contamination. In this study, significant linear correlations of gamma-emitting radionuclides were found with mass of dust and occurrence frequency of AD. Regardless of the source origin of the dust, 137 Cs and 7 Be concentration primarily depended on dust mass in the filter. Nonetheless, the correlations were greatly distorted in 2011 and in the spring season, particularly the correlations with AD days that were far below that of the correlations obtained for the whole study period. A possible explanation of these conflicting results is that a change in the dust source could appreciably alter the concentration, deposition, and distribution of airborne radionuclides

Geomorphic and land cover identification of dust sources in the eastern Great Basin of Utah, U.S.A.

Science.gov (United States)

Hahnenberger, Maura; Nicoll, Kathleen

2014-01-01

This study identifies anthropogenically disturbed areas and barren playa surfaces as the two primary dust source types that repeatedly contribute to dust storm events in the eastern Great Basin of western Utah, U.S.A. This semi-arid desert region is an important contributor to dust production in North America, with this study being the first to specifically identify and characterize regional dust sources. From 2004 to 2010, a total of 51 dust event days (DEDs) affected the air quality in Salt Lake City, UT. MODIS satellite imagery during 16 of these DEDs was analyzed to identify dust plumes, and assess the characteristics of dust source areas. A total of 168 plumes were identified, and showed mobilization of dust from Quaternary deposits located within the Bonneville Basin. This analysis identifies 4 major and 5 secondary source areas for dust in this region, which produce dust primarily during the spring and fall months and during moderate or greater drought conditions, with a Palmer Drought Index (PDI) of - 2 or less. The largest number of observed dust plumes (~ 60% of all plumes) originated from playas (ephemeral lakes) and are classified as barren land cover with a silty clay soil sediment surface. Playa surfaces in this region undergo numerous recurrent anthropogenic disturbances, including military operations and anthropogenic water withdrawal. Anthropogenic disturbance is necessary to produce dust from the vegetated landscape in the eastern Great Basin, as evidenced by the new dust source active from 2008 to 2010 in the area burned by the 2007 Milford Flat Fire; this fire was the largest in Utah's history due to extensive cover of invasive cheatgrass (Bromus tectorum) along with drought conditions. However, dust mobilization from the Milford Flat Burned Area was limited to regions that had been significantly disturbed by post-fire land management techniques that consisted of seeding, followed by chaining or tilling of the soil. Dust storms in the eastern

(dust, PM10 , and BC) using CHIMERE chemistry tra

Indian Academy of Sciences (India)

The objective of this study is to evaluate the ability of a European chemistry transport model,. 'CHIMERE' driven by ..... tive days in May 2008 (12–16 May) to simulate the dust storm ...... Regional Office for Europe, Copenhagen. Zender C, Bian ...

Overview of Asian Biomass Burning and Dust Aerosols Measured during the Dongsha Experiment in the Spring of 2010

Science.gov (United States)

Lin, N.; Tsay, S.; Wang, S.; Sheu, G.; Chi, K.; Lee, C.; Wang, J.

2010-12-01

launched four times per day during the IOPs. This experiment provides a relatively complete dataset of aerosol chemistry and physical observations conducted in the source/sink region for below marine boundary layer and lower free troposphere of biomass burning/air pollutants in the northern SE Asia. This presentation will give an overview of this experiment and its preliminary results, including a severe and unusual Asian dust event that was observed in Dognsha Island.

Can Asian Dust Trigger Phytoplankton Blooms in the Oligotrophic Northern South China Sea?

Science.gov (United States)

Wang, Sheng Hsiang; Hsu, Nai-Yung Christina; Tsay, Si-Chee; Lin, Neng-Huei; Sayer, Andrew M.; Huang, Shih-Jen; Lau, William K. M.

2012-01-01

Satellite data estimate a high dust deposition flux (approximately 18 g m(exp-2 a(exp-1) into the northern South China Sea (SCS). However, observational evidence concerning any biological response to dust fertilization is sparse. In this study, we combined long-term aerosol and chlorophyll-a (Chl-a) measurements from satellite sensors (MODIS and SeaWiFS) with a 16-year record of dust events from surface PM10 observations to investigate dust transport, flux, and the changes in Chl-a concentration over the northern SCS. Our result revealed that readily identifiable strong dust events over this region, although relatively rare (6 cases since 1994) and accounting for only a small proportion of the total dust deposition (approximately 0.28 g m(exp-2 a(exp-1), do occur and could significantly enhance phytoplankton blooms. Following such events, the Chl-a concentration increased up to 4-fold, and generally doubled the springtime background value (0.15 mg m(exp-3). We suggest these heavy dust events contain readily bioavailable iron and enhance the phytoplankton growth in the oligotrophic northern SCS.

Dust modelling and forecasting in the Barcelona Supercomputing Center: Activities and developments

Energy Technology Data Exchange (ETDEWEB)

Perez, C; Baldasano, J M; Jimenez-Guerrero, P; Jorba, O; Haustein, K; Basart, S [Earth Sciences Department. Barcelona Supercomputing Center. Barcelona (Spain); Cuevas, E [Izanaa Atmospheric Research Center. Agencia Estatal de Meteorologia, Tenerife (Spain); Nickovic, S [Atmospheric Research and Environment Branch, World Meteorological Organization, Geneva (Switzerland)], E-mail: carlos.perez@bsc.es

2009-03-01

The Barcelona Supercomputing Center (BSC) is the National Supercomputer Facility in Spain, hosting MareNostrum, one of the most powerful Supercomputers in Europe. The Earth Sciences Department of BSC operates daily regional dust and air quality forecasts and conducts intensive modelling research for short-term operational prediction. This contribution summarizes the latest developments and current activities in the field of sand and dust storm modelling and forecasting.

Dust modelling and forecasting in the Barcelona Supercomputing Center: Activities and developments

International Nuclear Information System (INIS)

Perez, C; Baldasano, J M; Jimenez-Guerrero, P; Jorba, O; Haustein, K; Basart, S; Cuevas, E; Nickovic, S

2009-01-01

The Barcelona Supercomputing Center (BSC) is the National Supercomputer Facility in Spain, hosting MareNostrum, one of the most powerful Supercomputers in Europe. The Earth Sciences Department of BSC operates daily regional dust and air quality forecasts and conducts intensive modelling research for short-term operational prediction. This contribution summarizes the latest developments and current activities in the field of sand and dust storm modelling and forecasting.

Snow–Dust Storm: Unique case study from Iceland, March 6–7, 2013

Czech Academy of Sciences Publication Activity Database

Dagsson-Waldhauserova, P.; Arnalds, O.; Olafsson, H.; Hladil, Jindřich; Skála, Roman; Navrátil, Tomáš; Chadimová, Leona; Meinander, O.

2015-01-01

Roč. 16, March (2015), s. 69-74 ISSN 1875-9637 Institutional support: RVO:67985831 Keywords : snow dust deposition * atmosphere cryosphere interactions * volcanic dust * natural phenomenon * Arctic Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.275, year: 2015

On the dust load and rainfall relationship in South Asia: an analysis from CMIP5

Science.gov (United States)

Singh, Charu; Ganguly, Dilip; Dash, S. K.

2018-01-01

This study is aimed at examining the consistency of the relationship between load of dust and rainfall simulated by different climate models and its implication for the Indian summer monsoon system. Monthly mean outputs of 12 climate models, obtained from the archive of the Coupled Model Intercomparison Project phase 5 (CMIP5) for the period 1951-2004, are analyzed to investigate the relationship between dust and rainfall. Comparative analysis of the model simulated precipitation with the India Meteorological Department (IMD) gridded rainfall, CRU TS3.21 and GPCP version 2.2 data sets show significant differences between the spatial patterns of JJAS rainfall as well as annual cycle of rainfall simulated by various models and observations. Similarly, significant inter-model differences are also noted in the simulation of load of dust, nevertheless it is further noted that most of the CMIP5 models are able to capture the major dust sources across the study region. Although the scatter plot analysis and the lead-lag pattern correlation between the dust load and the rainfall show strong relationship between the dust load over distant sources and the rainfall in the South Asian region in individual models, the temporal scale of this association indicates large differences amongst the models. Our results caution that it would be pre-mature to draw any robust conclusions on the time scale of the relationship between dust and the rainfall in the South Asian region based on either CMIP5 results or limited number of previous studies. Hence, we would like to emphasize upon the fact that any conclusions drawn on the relationship between the dust load and the South Asian rainfall using model simulation is highly dependent on the degree of complexity incorporated in those models such as the representation of aerosol life cycle, their interaction with clouds, precipitation and other components of the climate system.

Influence of dust and mud on the optical, chemical, and mechanical properties of a pv protective glass.

Science.gov (United States)

Yilbas, Bekir Sami; Ali, Haider; Khaled, Mazen M; Al-Aqeeli, Nasser; Abu-Dheir, Numan; Varanasi, Kripa K

2015-10-30

Recent developments in climate change have increased the frequency of dust storms in the Middle East. Dust storms significantly influence the performances of solar energy harvesting systems, particularly (photovoltaic) PV systems. The characteristics of the dust and the mud formed from this dust are examined using various analytical tools, including optical, scanning electron, and atomic force microscopies, X-ray diffraction, energy spectroscopy, and Fourier transform infrared spectroscopy. The adhesion, cohesion and frictional forces present during the removal of dry mud from the glass surface are determined using a microtribometer. Alkali and alkaline earth metal compounds in the dust dissolve in water to form a chemically active solution at the glass surface. This solution modifies the texture of the glass surface, thereby increasing the microhardness and decreasing the transmittance of the incident optical radiation. The force required to remove the dry mud from the glass surface is high due to the cohesive forces that result from the dried mud solution at the interface between the mud and the glass. The ability altering the characteristics of the glass surface could address the dust/mud-related limitations of protective surfaces and has implications for efficiency enhancements in solar energy systems.

Correlation between Yellow Dust and Radioactivity

Energy Technology Data Exchange (ETDEWEB)

AIZaabia, Mouza A [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Kim, Byoung-Jik [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

2015-10-15

In East Asia, yellow dust or Asian Dust (AD) outbreaks are among the largest contributors of wind-blown dust that carry natural and anthropogenic radionuclides and subsequently alter their concentration and distribution throughout the environment. Although the Korean Peninsula has been experiencing AD events since ancient times, the research has tended to focus on the transport routes and characteristics of AD, rather than on its impact on radionuclide activity levels. This paper examines the relationship between radionuclide concentration in the air and the frequency of dusty days in South Korea during AD intrusion events. It also investigates whether increased radionuclide concentration is a function of either more mass or more dust contamination. In this study, significant linear correlations of gamma-emitting radionuclides were found with mass of dust and occurrence frequency of AD. Regardless of the source origin of the dust, {sup 137}Cs and {sup 7}Be concentration primarily depended on dust mass in the filter. Nonetheless, the correlations were greatly distorted in 2011 and in the spring season, particularly the correlations with AD days that were far below that of the correlations obtained for the whole study period. A possible explanation of these conflicting results is that a change in the dust source could appreciably alter the concentration, deposition, and distribution of airborne radionuclides.

Disturbance to desert soil ecosystems contributes to dust-mediated impacts at regional scales

Science.gov (United States)

Pointing, Stephen B.; Belnap, Jayne

2014-01-01

This review considers the regional scale of impacts arising from disturbance to desert soil ecosystems. Deserts occupy over one-third of the Earth’s terrestrial surface, and biological soil covers are critical to stabilization of desert soils. Disturbance to these can contribute to massive destabilization and mobilization of dust. This results in dust storms that are transported across inter-continental distances where they have profound negative impacts. Dust deposition at high altitudes causes radiative forcing of snowpack that leads directly to altered hydrological regimes and changes to freshwater biogeochemistry. In marine environments dust deposition impacts phytoplankton diazotrophy, and causes coral reef senescence. Increasingly dust is also recognized as a threat to human health.

Physical properties of suspended dust during moist and low wind conditions in Iceland

Czech Academy of Sciences Publication Activity Database

Dagsson-Waldhauserova, P.; Arnalds, O.; Olafsson, H.; Škrabalová, L.; Sigurdardottir, G. M.; Braniš, M.; Hladil, Jindřich; Skála, Roman; Navrátil, Tomáš; Chadimová, Leona; Lowis of Menar, S.; Thorsteinsson, T.; Carlsen, H. K.; Jonsdottir, I.

2014-01-01

Roč. 27, č. 1 (2014), s. 25-39 ISSN 1670-567X Institutional support: RVO:67985831 Keywords : atmospheric measurements * dust storm event * surface heating * dust aerosol * climate aspects Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.188, year: 2014 http://www.ias.is/landbunadur/wgsamvef.nsf/Attachment/IAS%20-%204%20kafli%20Pavla/$file/IAS%20-%204%20kafli%20Pavla.pdf

Dust modeling over East Asia during the summer of 2010 using the WRF-Chem model

Science.gov (United States)

Zhang, B.; Huang, J.; Chen, S.

2017-12-01

An intense summer dust storm over East Asia during June 24-27, 2010, was systematically analyzed using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) and a variety of in situ measurements and satellite retrievals. The results showed that the WRF-Chem model captured the spatial and temporal distributions of meteorological factors and dust aerosols over East Asia. This summer dust storm was initiated by the approach of a transverse trough in the northwestern Xinjiang. Because of the passage of the cutoff-low, a large amount of cold air was transported southward and further enhanced in the narrow valleys of the Altai and Tianshan Mountains, which resulted in higher wind speeds and huge dust emissions over the Taklimakan Desert (TD). Dust emission fluxes over the TD were as high as 54 μg m-2 s-1 on June 25th. The dust aerosols from the TD then swept across Inner Mongolia, Ningxia and Mongolia, and some were also transported eastward to Beijing, Tianjin, the Hebei region, and even South Korea and Japan. The simulations further showed that summer dust over East Asia exerts an important influence on the radiation budget in the Earth-atmosphere system. Dust heat the atmosphere at a maximum heating rate of 0.14 k day-1, effectively changing the vertical stability of the atmosphere and affecting climate change at regional and even global scales. The dust event-averaged direct radiative forcing induced by dust particles over the TD at all-sky was -6.0, -16.8 and 10.8 W m-2 at the top of the atmosphere, the surface, and in the atmosphere, respectively.

Identification of possible intense historical geomagnetic storms using combined sunspot and auroral observations from East Asia

Directory of Open Access Journals (Sweden)

D. M. Willis

2005-03-01

Full Text Available Comprehensive catalogues of ancient sunspot and auroral observations from East Asia are used to identify possible intense historical geomagnetic storms in the interval 210 BC-AD 1918. There are about 270 entries in the sunspot catalogue and about 1150 entries in the auroral catalogue. Special databases have been constructed in which the scientific information in these two catalogues is placed in specified fields. For the purposes of this study, an historical geomagnetic storm is defined in terms of an auroral observation that is apparently associated with a particular sunspot observation, in the sense that the auroral observation occurred within several days of the sunspot observation. More precisely, a selection criterion is formulated for the automatic identification of such geomagnetic storms, using the oriental records stored in the sunspot and auroral databases. The selection criterion is based on specific assumptions about the duration of sunspot visibility with the unaided eye, the likely range of heliographic longitudes of an energetic solar feature, and the likely range of transit times for ejected solar plasma to travel from the Sun to the Earth. This selection criterion results in the identification of nineteen putative historical geomagnetic storms, although two of these storms are spurious in the sense that there are two examples of a single sunspot observation being associated with two different auroral observations separated by more than half a (synodic solar rotation period. The literary and scientific reliabilities of the East Asian sunspot and auroral records that define the nineteen historical geomagnetic storms are discussed in detail in a set of appendices. A possible time sequence of events is presented for each geomagnetic storm, including possible dates for both the central meridian passage of the sunspot and the occurrence of the energetic solar feature, as well as likely transit times for the ejected solar plasma

Atmospheric deposition of radioactive cesium (137Cs) associated with dust events in East Asia

International Nuclear Information System (INIS)

Fujiwara, H.

2010-01-01

Since the cessation of atmospheric nuclear testing in 1980, there has been no known serious atmospheric contamination by radioactive cesium (sup(137)Cs) apart from the Chernobyl nuclear reactor accident in 1986. There now remain only small amounts of anthropogenic radionuclides in the atmosphere that can be directly related to past testing. However, sup(137)Cs is still regularly found in atmospheric deposition samples in Japan. In this study, we analyzed sup(137)Cs monitoring data, meteorological data, and field survey results to investigate the recent transport and deposition of sup(137)Cs associated with dust phenomena. Monthly records of nationwide sup(137)Cs deposition in Japan during the 1990s show a consistent seasonal variation, with higher levels of deposition occurring in spring. In March 2002, an unexpectedly high amount of sup(137)Cs was deposited in the northwestern coastal area of Japan at the same time as an Asian dust event was observed. Analysis of land-based weather data showed that sandstorms and other dust-raising phenomena also occurred in March 2002 over areas of Mongolia and northeastern China where grassland and shrubs predominated. Furthermore, radioactivity measurements showed sup(137)Cs enrichment in the surface layer of grassland soils in the areas affected by these sandstorms. These results suggest that grasslands are potential sources of sup(137)Cs-bearing dust. Continued desertification of the East Asian continent in response to recent climate change can be expected to result in an increase in sup(137)Cs-bearing soil particles in the atmosphere, and their subsequent re-deposition in Japan. However, soil dust is also raised around Japanese monitoring sites by the strong winds that are common in Japan in spring, and this local dust might also contribute to sup(137)Cs deposition in Japan. To estimate the relative contributions of local and distant dust events to the total sup(137)Cs deposition, we monitored deposition of mineral particles

Assessment of state-of-the-art dust emission scheme in GEOS

Science.gov (United States)

Darmenov, A.; Liu, X.; Prigent, C.

2017-12-01

The GEOS modeling system has been extended with state-of-the-art parameterization of dust emissions based on the vertical flux formulation described in Kok et al., 2014. The new dust scheme was coupled with the GOCART and MAM aerosol models. In the present study we compared dust emissions, aerosol optical depth (AOD) and radiative fluxes from GEOS experiments with the standard and new dust emissions. AOD from the model experiments were also compared with AERONET and satellite based AOD product. Based on this comparative analysis we concluded that the new parameterization improved the GEOS capability to model dust aerosols originating from African sources, however it led to overestimation of dust emissions from Asian and Middle-Eastern sources. Further regional tuning of key parameters controlling the threshold friction velocity may be required in order to attain more definitive and uniform improvement in the dust modeling skill with the newly implemented dust emissions scheme.

Optical and microphysical properties of natural mineral dust and anthropogenic soil dust near dust source regions over northwestern China

Science.gov (United States)

Wang, Xin; Wen, Hui; Shi, Jinsen; Bi, Jianrong; Huang, Zhongwei; Zhang, Beidou; Zhou, Tian; Fu, Kaiqi; Chen, Quanliang; Xin, Jinyuan

2018-02-01

Mineral dust aerosols (MDs) not only influence the climate by scattering and absorbing solar radiation but also modify cloud properties and change the ecosystem. From 3 April to 16 May 2014, a ground-based mobile laboratory was deployed to measure the optical and microphysical properties of MDs near dust source regions in Wuwei, Zhangye, and Dunhuang (in chronological order) along the Hexi Corridor over northwestern China. Throughout this dust campaign, the hourly averaged (±standard deviation) aerosol scattering coefficients (σsp, 550 nm) of the particulates with aerodynamic diameters less than 2.5 µm (PM2.5) at these three sites were sequentially 101.5 ± 36.8, 182.2 ± 433.1, and 54.0 ± 32.0 Mm-1. Correspondingly, the absorption coefficients (σap, 637 nm) were 9.7 ± 6.1, 6.0 ± 4.6, and 2.3 ± 0.9 Mm-1; single-scattering albedos (ω, 637 nm) were 0.902 ± 0.025, 0.931 ± 0.037, and 0.949 ± 0.020; and scattering Ångström exponents (Åsp, 450-700 nm) of PM2.5 were 1.28 ± 0.27, 0.77 ± 0.51, and 0.52 ± 0.31. During a severe dust storm in Zhangye (i.e., from 23 to 25 April), the highest values of σsp2.5 ( ˜ 5074 Mm-1), backscattering coefficient (σbsp2.5, ˜ 522 Mm-1), and ω637 ( ˜ 0.993) and the lowest values of backscattering fraction (b2.5, ˜ 0.101) at 550 nm and Åsp2.5 ( ˜ -0.046) at 450-700 nm, with peak values of aerosol number size distribution (appearing at the particle diameter range of 1-3 µm), exhibited that the atmospheric aerosols were dominated by coarse-mode dust aerosols. It is hypothesized that the relatively higher values of mass scattering efficiency during floating dust episodes in Wuwei and Zhangye are attributed to the anthropogenic soil dust produced by agricultural cultivations.

Long-term variability of dust events in Iceland (1949-2011)

Science.gov (United States)

Dagsson-Waldhauserova, P.; Arnalds, O.; Olafsson, H.

2014-12-01

The long-term frequency of atmospheric dust observations was investigated for the southern part of Iceland and interpreted together with earlier results obtained from northeastern (NE) Iceland (Dagsson-Waldhauserova et al., 2013). In total, over 34 dust days per year on average occurred in Iceland based on conventionally used synoptic codes for dust observations. However, frequent volcanic eruptions, with the re-suspension of volcanic materials and dust haze, increased the number of dust events fourfold (135 dust days annually). The position of the Icelandic Low determined whether dust events occurred in the NE (16.4 dust days annually) or in the southern (S) part of Iceland (about 18 dust days annually). The decade with the most frequent dust days in S Iceland was the 1960s, but the 2000s in NE Iceland. A total of 32 severe dust storms (visibility typically warm, occurring during summer/autumn (May-September) and during mild southwesterly winds, while the subarctic dust events (S Iceland) were mainly cold, occurring during winter/spring (March-May) and during strong northeasterly winds. About half of the dust events in S Iceland occurred in winter or at sub-zero temperatures. A good correlation was found between particulate matter (PM10) concentrations and visibility during dust observations at the stations Vík and Stórhöfði. This study shows that Iceland is among the dustiest areas of the world and that dust is emitted year-round.

Cavity Ring-Down Measurement of Aerosol Optical Properties During the Asian Dust Above Monterey Experiment and DOE Aerosol Intensive Operating Period

Science.gov (United States)

Ricci, K.; Strawa, A. W.; Provencal, R.; Castaneda, R.; Bucholtz, A.; Schmid, B.

2004-01-01

Large uncertainties in the effects of aerosols on climate require improved in-situ measurements of extinction coefficient and single-scattering albedo. This paper describes preliminary results from Cadenza, a new continuous wave cavity ring-down (CW-CRD) instrument designed to address these uncertainties. Cadenza measures the aerosol extinction coefficient for 675 nm and 1550 nm light, and simultaneously measures the scattering coefficient at 675 nm. In the past year Cadenza was deployed in the Asian Dust Above Monterey (ADAM) and DOE Aerosol Intensive Operating Period (IOP) field projects. During these flights Cadenza produced measurements of aerosol extinction in the range from 0.2 to 300/Mm with an estimated precision of 0.1/Mm for 1550 nm light and 0.2/Mm for 675 nm light. Cadenza data from the ADAM and Aerosol IOP missions compared favorably with data from the other instruments aboard the CIRPAS Twin Otter aircraft and participating in those projects. We present comparisons between the Cadenza measurements and those from a TSI nephelometer, Particle Soot Absorption Photometer (PSAP), and the AATS 14 sun-photometer. Measurements of the optical properties of smoke and dust plumes sampled during these campaigns are presented and estimates of heating rates due to these plumes are made.

Impact of Asian Aerosols on Precipitation Over California: An Observational and Model Based Approach

Science.gov (United States)

Naeger, Aaron R.; Molthan, Andrew L.; Zavodsky, Bradley T.; Creamean, Jessie M.

2015-01-01

Dust and pollution emissions from Asia are often transported across the Pacific Ocean to over the western United States. Therefore, it is essential to fully understand the impact of these aerosols on clouds and precipitation forming over the eastern Pacific and western United States, especially during atmospheric river events that account for up to half of California's annual precipitation and can lead to widespread flooding. In order for numerical modeling simulations to accurately represent the present and future regional climate of the western United States, we must account for the aerosol-cloud-precipitation interactions associated with Asian dust and pollution aerosols. Therefore, we have constructed a detailed study utilizing multi-sensor satellite observations, NOAA-led field campaign measurements, and targeted numerical modeling studies where Asian aerosols interacted with cloud and precipitation processes over the western United States. In particular, we utilize aerosol optical depth retrievals from the NASA Moderate Resolution Imaging Spectroradiometer (MODIS), NOAA Geostationary Operational Environmental Satellite (GOES-11), and Japan Meteorological Agency (JMA) Multi-functional Transport Satellite (MTSAT) to effectively detect and monitor the trans-Pacific transport of Asian dust and pollution. The aerosol optical depth (AOD) retrievals are used in assimilating the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) in order to provide the model with an accurate representation of the aerosol spatial distribution across the Pacific. We conduct WRF-Chem model simulations of several cold-season atmospheric river events that interacted with Asian aerosols and brought significant precipitation over California during February-March 2011 when the NOAA CalWater field campaign was ongoing. The CalWater field campaign consisted of aircraft and surface measurements of aerosol and precipitation processes that help extensively validate our WRF

Asian sand dust enhances murine lung inflammation caused by Klebsiella pneumoniae

International Nuclear Information System (INIS)

He, Miao; Ichinose, Takamichi; Yoshida, Seiichi; Yamamoto, Shoji; Inoue, Ken-ichiro; Takano, Hirohisa; Yanagisawa, Rie; Nishikawa, Masataka; Mori, Ikuko; Sun, Guifan; Shibamoto, Takayuki

2012-01-01

Inhaling concomitants from Asian sand dust (ASD) may result in exacerbation of pneumonia by the pathogen. The exacerbating effect of ASD on pneumonia induced by Klebsiella pneumoniae (KP) was investigated in ICR mice. The organic substances adsorbed onto ASD collected from the atmosphere of Iki-island in Japan were excluded by heat treatment at 360 °C for 30 min. ICR mice were instilled intratracheally with ASD at doses of 0.05 mg or 0.2 mg/mouse four times at 2-week intervals (total dose of 0.2 mg or 0.8 mg/mouse) and were administrated with ASD in the presence or absence of KP at the last intratracheal instillation. Pathologically, ASD caused exacerbation of pneumonia by KP as shown by increased inflammatory cells within the bronchiolar and the alveolar compartments. ASD enhanced the neutrophil number dose dependently as well as the expression of cytokines (IL-1β, IL-6, IL-12, IFN-γ, TNF-α) and chemokines (KC, MCP-1, MIP-1α) related to KP in BALF. In an in vitro study using RAW264.7 cells, combined treatment of ASD and KP increased gene expression of IL-1β, IL-6, IFN-β, KC, MCP-1, and MIP-1α. The same treatment tended to increase the protein level of IL-1β, TNF-α and MCP-1 in a culture medium compared to each treatment alone. The combined treatment tended to increase the gene expression of Toll-like receptor 2 (TLR2), and NALP3, ASC and caspase-1 compared with KP alone. These results suggest that the exacerbation of pneumonia by ASD + KP was due to the enhanced production of pro-inflammatory mediators via activation of TLR2 and NALP3 inflammasome pathways in alveolar macrophages.

Asian sand dust enhances murine lung inflammation caused by Klebsiella pneumoniae

Energy Technology Data Exchange (ETDEWEB)

He, Miao [Department of Environmental and Occupational Health, College of Public Health, China Medical University, 11001, Shenyang (China); Ichinose, Takamichi; Yoshida, Seiichi [Department of Health Sciences, Oita University of Nursing and Health Sciences, 870-1201, Oita (Japan); Yamamoto, Shoji; Inoue, Ken-ichiro; Takano, Hirohisa; Yanagisawa, Rie [Pathophysiology Research Team, National Institute for Environmental Studies, 305-8506, Tsukuba, Ibaraki (Japan); Nishikawa, Masataka; Mori, Ikuko [Environmental Chemistry Division, National Institute for Environmental Studies, 305-8506, Tsukuba, Ibaraki (Japan); Sun, Guifan [Department of Environmental and Occupational Health, College of Public Health, China Medical University, 11001, Shenyang (China); Shibamoto, Takayuki, E-mail: tshibamoto@ucdavis.edu [Department of Environmental Toxicology, University of California, Davis, CA 95616 (United States)

2012-01-15

Inhaling concomitants from Asian sand dust (ASD) may result in exacerbation of pneumonia by the pathogen. The exacerbating effect of ASD on pneumonia induced by Klebsiella pneumoniae (KP) was investigated in ICR mice. The organic substances adsorbed onto ASD collected from the atmosphere of Iki-island in Japan were excluded by heat treatment at 360 °C for 30 min. ICR mice were instilled intratracheally with ASD at doses of 0.05 mg or 0.2 mg/mouse four times at 2-week intervals (total dose of 0.2 mg or 0.8 mg/mouse) and were administrated with ASD in the presence or absence of KP at the last intratracheal instillation. Pathologically, ASD caused exacerbation of pneumonia by KP as shown by increased inflammatory cells within the bronchiolar and the alveolar compartments. ASD enhanced the neutrophil number dose dependently as well as the expression of cytokines (IL-1β, IL-6, IL-12, IFN-γ, TNF-α) and chemokines (KC, MCP-1, MIP-1α) related to KP in BALF. In an in vitro study using RAW264.7 cells, combined treatment of ASD and KP increased gene expression of IL-1β, IL-6, IFN-β, KC, MCP-1, and MIP-1α. The same treatment tended to increase the protein level of IL-1β, TNF-α and MCP-1 in a culture medium compared to each treatment alone. The combined treatment tended to increase the gene expression of Toll-like receptor 2 (TLR2), and NALP3, ASC and caspase-1 compared with KP alone. These results suggest that the exacerbation of pneumonia by ASD + KP was due to the enhanced production of pro-inflammatory mediators via activation of TLR2 and NALP3 inflammasome pathways in alveolar macrophages.

Influence of tropical storms in the Northern Indian Ocean on dust entrainment and long-range transport.

Digital Repository Service at National Institute of Oceanography (India)

Ramaswamy, V.

to the winter and summer Shamal Winds, tropical cyclones are an important mechanism of dust entrainment and transport of dust in this region. Elevated dust levels were observed in the northern Arabian Sea during most tropical cyclone events. During the study...

Characterization of Dust Properties at the Source Region During ACE-Asia

Science.gov (United States)

Tsay, Si-Chee; Lau, William (Technical Monitor)

2001-01-01

ACE (Aerosol Characterization Experiment)-Asia is designed to study the compelling variability in spatial and temporal scale of both pollution-derived and naturally-occurring aerosols, which often exist in high concentrations over eastern Asia and along the rim of the western Pacific. The phase-I of ACE-Asia was conducted from March-May 2001 in the vicinity of the Gobi desert, east coast of China, Yellow Sea, Korea, and Japan, along the pathway of Kosa (severe events that blanket East Asia with yellow desert dust, peaked in the Spring season). Asian dust typically originates in desert areas far from polluted urban regions. During transport, dust layers can interact with anthropogenic sulfate and soot aerosols from heavily polluted urban areas. Added to the complex effects of clouds and natural marine aerosols, dust particles reaching the marine environment can have drastically different properties than those from the source. Thus, understanding the unique temporal and spatial variations of Asian dust is of special importance in regional-to-global climate issues such as radiative forcing, the hydrological cycle, and primary biological productivity in the mid-Pacific Ocean. During ACE-Asia we have measured continuously aerosol optical/radiative properties, column precipitable water amount, and surface reflectivity over homogeneous areas from surface. The inclusion of flux measurements permits the determination of dust aerosol radiative flux in addition to measurements of loading and optical thickness. At the time of the Terra/MODIS overpass, these ground-based observations can provide valuable data to compare with MODIS retrievals over land. Preliminary results will be presented and discussed their implications in regional climatic effects.

Effect of wind speed and relative humidity on atmospheric dust concentrations in semi-arid climates.

Science.gov (United States)

Csavina, Janae; Field, Jason; Félix, Omar; Corral-Avitia, Alba Y; Sáez, A Eduardo; Betterton, Eric A

2014-07-15

Atmospheric particulate have deleterious impacts on human health. Predicting dust and aerosol emission and transport would be helpful to reduce harmful impacts but, despite numerous studies, prediction of dust events and contaminant transport in dust remains challenging. In this work, we show that relative humidity and wind speed are both determinants in atmospheric dust concentration. Observations of atmospheric dust concentrations in Green Valley, AZ, USA, and Juárez, Chihuahua, México, show that PM10 concentrations are not directly correlated with wind speed or relative humidity separately. However, selecting the data for high wind speeds (>4m/s at 10 m elevation), a definite trend is observed between dust concentration and relative humidity: dust concentration increases with relative humidity, reaching a maximum around 25% and it subsequently decreases with relative humidity. Models for dust storm forecasting may be improved by utilizing atmospheric humidity and wind speed as main drivers for dust generation and transport. Copyright © 2014 Elsevier B.V. All rights reserved.

Impact of atmospheric circulation types on southwest Asian dust and Indian summer monsoon rainfall

Science.gov (United States)

Kaskaoutis, D. G.; Houssos, E. E.; Solmon, F.; Legrand, M.; Rashki, A.; Dumka, U. C.; Francois, P.; Gautam, R.; Singh, R. P.

2018-03-01

This study examines the meteorological feedback on dust aerosols and rainfall over the Arabian Sea and India during the summer monsoon using satellite data, re-analysis and a regional climate model. Based on days with excess aerosol loading over the central Ganges basin during May - September, two distinct atmospheric circulation types (weather clusters) are identified, which are associated with different dust-aerosol and rainfall distributions over south Asia, highlighting the role of meteorology on dust emissions and monsoon rainfall. Each cluster is characterized by different patterns of mean sea level pressure (MSLP), geopotential height at 700 hPa (Z700) and wind fields at 1000 hPa and at 700 hPa, thus modulating changes in dust-aerosol loading over the Arabian Sea. One cluster is associated with deepening of the Indian/Pakistan thermal low leading to (i) increased cyclonicity and thermal convection over northwestern India and Arabian Peninsula, (ii) intensification of the southwest monsoon off the Horn of Africa, iii) increase in dust emissions from Rub-Al-Khali and Somalian deserts, (iv) excess dust accumulation over the Arabian Sea and, (v) strengthening of the convergence of humid air masses and larger precipitation over Indian landmass compared to the other cluster. The RegCM4.4 model simulations for dust-aerosol and precipitation distributions support the meteorological fields and satellite observations, while the precipitation over India is positively correlated with the aerosol loading over the Arabian Sea on daily basis for both weather clusters. This study highlights the key role of meteorology and atmospheric dynamics on dust life cycle and rainfall over the monsoon-influenced south Asia.

"Dust Devils": Gardening Agents on the Surface of Mars, and Hidden Hazards to Human Exploration?

Science.gov (United States)

Marshall, J.; Smith, P.; White, B.; Farrell, W.

1999-09-01

dust devils are to be expected in reasonable abundance. First, from a geological perspective, the vortices will act as "gardening" agents for the top few centimeters of entrainable material. Over time (hundreds of millions, or billions of years being available), they will cover the surface with scouring paths, and the grain sizes that can be lofted by a vortex probably extends over the whole sand to dust range. The depositional paths are, of course, much larger, so that vortex-induced deposition is more widespread than vortex-induced erosion, and will without doubt, affect the whole region in which the dust devils occur (this might explain why rocks at the Viking site seemed oddly capped with dust in a region apparently subject to general aeolian scouring). On Mars, the lift forces in dust devils might be less than on earth owing to the much thinner atmosphere, but this may be counterbalanced by lower gravity and greater vortex velocities. Certainly, when active, other aeolian phenomena on Mars --sand motion and dust storms, seem no less energetic and no less capable of lofting sediments than equivalent terrestrial aeolian phenomena. Every several years, within the current climatic regime, the surface of Mars is subject to light dust fall from global dust storms. Over time, this should develop a very uniform surface layer, with commensurate uniformity in grain size, mineralogy, albedo, color, and general spectroscopic properties. Dust devils will disturb this situation by continually mixing the surface dust with underlying layers, perhaps composed of silt and sand. This size mixing will also involve compositional mixing. After some years, the thin layer of dust that may be difficult to entrain alone, becomes progressively mixed with coarser materials that could reduce the general aeolian threshold of the soil. Certainly the continual disturbance by vorticity will prevent surface stabilization that may bind or indurate grains (caused by slow cementation or ice welding

Chemical Composition Based Aerosol Optical Properties According to Size Distribution and Mixture Types during Smog and Asian Dust Events in Seoul, Korea

Science.gov (United States)

Jung, Chang Hoon; Lee, Ji Yi; Um, Junshik; Lee, Seung Soo; Kim, Yong Pyo

2018-02-01

This study investigated the optical properties of aerosols involved in different meteorological events, including smog and Asian dust days. Carbonaceous components and inorganic species were measured in Seoul, Korea between 25 and 31 March 2012. Based on the measurements, the optical properties of aerosols were calculated by considering composition, size distribution, and mixing state of aerosols. To represent polydisperse size distributions of aerosols, a lognormal size distribution with a wide range of geometric mean diameters and geometric standard deviations was used. For the optical property calculations, the Mie theory was used to compute single-scattering properties of aerosol particles with varying size and composition. Analysis of the sampled data showed that the water-soluble components of organic matter increased on smog days, whereas crustal elements increased on dust days. The water content significantly influenced the optical properties of aerosols during the smog days as a result of high relative humidity and an increase in the water-soluble component. The absorption coefficients depended on the aerosol mixture type and the aerosol size distributions. Therefore, to improve our knowledge on radiative impacts of aerosols, especially the regional impacts of aerosols in East Asia, accurate measurements of aerosols, such as size distribution, composition, and mixture type, under different meteorological conditions are required.

Occupational dermatoses: An Asian perspective.

Science.gov (United States)

Bhatia, Riti; Sharma, Vinod Kumar

2017-01-01

Occupational dermatoses contribute to a significant portion of work-related diseases, especially in Asia, where a major portion of the workforce is in the unorganized sector. This review article is focussed on the frequency and pattern of occupational skin diseases reported across Asian countries and type of allergens implicated in different occupations. The literature was searched systematically using key words 'occupational dermatoses,' 'occupational skin disease' and name of each Asian country. Ninty five full-text articles were considered relevant and evaluated. Some of the dermatoses seen in industrial workers in Asian countries are similar to those in Western countries, including dermatoses due to chromate in construction and electroplating workers, epoxy resin, and chromate in painters, wood dust in workers in the furniture industry, azo dyes in textile workers and formaldehyde and chromates in those working in the leather and dyeing industries, dermatoses in domestic workers, chefs and health-care workers. Dermatoses in workers engaged in agriculture, beedi (tiny cigars) manufacture, agarbatti (incense sticks) production, fish processing, carpet weaving, sanitation and those working in coffee plantations and coal mines appear to be unique to Asian countries. Recognition of clinical patterns and geographic variations in occupational skin diseases will provide an impetus to further strengthen future research in these areas, as well as improving their management.

Influence of Dust Loading on Atmospheric Ionizing Radiation on Mars

Science.gov (United States)

Norman, Ryan B.; Gronoff, Guillaume; Mertens, Christopher J.

2014-01-01

Measuring the radiation environment at the surface of Mars is the primary goal of the Radiation Assessment Detector on the NASA Mars Science Laboratory's Curiosity rover. One of the conditions that Curiosity will likely encounter is a dust storm. The objective of this paper is to compute the cosmic ray ionization in different conditions, including dust storms, as these various conditions are likely to be encountered by Curiosity at some point. In the present work, the Nowcast of Atmospheric Ionizing Radiation for Aviation Safety model, recently modified for Mars, was used along with the Badhwar & O'Neill 2010 galactic cosmic ray model. In addition to galactic cosmic rays, five different solar energetic particle event spectra were considered. For all input radiation environments, radiation dose throughout the atmosphere and at the surface was investigated as a function of atmospheric dust loading. It is demonstrated that for galactic cosmic rays, the ionization depends strongly on the atmosphere profile. Moreover, it is shown that solar energetic particle events strongly increase the ionization throughout the atmosphere, including ground level, and can account for the radio blackout conditions observed by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument on the Mars Express spacecraft. These results demonstrate that the cosmic rays' influence on the Martian surface chemistry is strongly dependent on solar and atmospheric conditions that should be taken into account for future studies.

Modeling wind-blown desert dust in the southwestern United States for public health warning: A case study

Science.gov (United States)

Yin, Dazhong; Nickovic, Slobodan; Barbaris, Brian; Chandy, Beena; Sprigg, William A.

A model for simulating desert dust cycle was adapted and applied for a dust storm case in the southwest United States (US). This is an initial test of the model's capability as part of a future public health early warning system. The modeled meteorological fields, which drive a dust storm, were evaluated against surface and upper-air measurement data. The modeled dust fields were compared with satellite images, in situ surface PM2.5 and PM10 data, and visibility data in the areas affected by the dust event. The model predicted meteorological fields reasonably well. The modeled surface and upper-air field patterns were in agreement with the measured ones. The vertical profiles of wind, temperature, and humidity followed closely with the observed profiles. Statistical analyses of modeled and observed meteorological variables at surface sites showed fairly good model performance. The modeled dust spatial distributions were comparable with the satellite-observed dust clouds and the reduced visibility patterns. Most encouragingly, the model-predicted and observed PM2.5 peak hours matched reasonably well. The model produced better PM2.5 peak hours than PM10 peak hours. The temporal varying trends of daily and hourly PM2.5 and PM10 concentrations at most of the measurement sites were similar to those observed. Discrepancies between the values of the modeled and the measured surface PM2.5 and PM10 concentrations differed with time and location. Sometimes the modeled and measured concentrations can have one order of magnitude differences. These revealed there were possible deficiencies in the simulation of the dust production strength and location, and the representation of dust particle size in the modeling. Better land surface data and size representation of the dust production are expected to further improve model performance.

Saharan and Arabian Dust Aerosols: A Comparative Case Study of Lidar Ratio

Directory of Open Access Journals (Sweden)

Córdoba-Jabonero Carmen

2016-01-01

Full Text Available This work presents a first comparative study of the Lidar Ratio (LR values obtained for dust particles in two singular dust-influenced regions: the Canary Islands (Spain, close to the African coast in the North Atlantic Ocean, frequently affected by Saharan dust intrusions, and the Kuwait area (Arabian Peninsula as usually influenced by Arabian dust storms. Synergetic lidar and sun-photometry measurements are carried out in two stations located in these particular regions for that purpose. Several dusty cases were observed during 2014 in both stations and, just for illustration, two specific dusty case studies have been selected and analyzed to be shown in this work. In general, mean LR values of 54 sr and 40 sr were obtained in these studies cases for Saharan and Arabian dust particles, respectively. Indeed, these results are in agreement with other studies performed for dust particles arriving from similar desert areas. In particular, the disparity found in Saharan and Arabian dust LR values can be based on the singular composition of the suspended dust aerosols over each station. These results can be useful for CALIPSO extinction retrievals, where a single LR value (40 sr is assumed for pure dust particles independently on the dust source region.

Dust fluxes linked to intensification of Prevailing Westerlies and Trade Winds stimulated Ethmodiscus rex giant diatom blooms in the southern Mariana Trench, western tropical Pacific at onset of the Last Glacial Maximum

Science.gov (United States)

Chen, D.; Luo, M.; Algeo, T. J.; Chen, L.

2017-12-01

The strontium (Sr) and neodymium (Nd) isotope compositions and clay-mineral assemblages of the detrital fraction of sediments in the southern Mariana Trench together with major- and trace-elements concentrations of bulk sediments have been determined to trace the sediment provenance and investigate the relationship between Asian dust input and blooms of the giant diatom Ethmodiscus rex. Enrichment of barium (Ba) in relative to upper continental crust (UCC) and low average Rb/K ratios in all study cores point to both hydrothermal and volcaniclastic inputs to the sediments. Both the Sr-Nd isotope compositions and the clay-mineral assemblages of the detrital fraction reflect a two-component mixing system consisting of Mariana arc volcaniclastics and eolian Asian dust. A decrease in smectite content and an increase in illite content just before formation of laminated diatom mats (LDMs) suggest a change in the source of the eolian dust from eastern Asian deserts (EADs) to central Asian deserts (CADs) at the onset of the Last Glacial Maximum (LGM). This observation suggests a causal linkage between atmospheric circulation patterns, the sources of eolian Asian dust, and marine productivity in the western Pacific region. We postulate that the shift to CAD-sourced dust may have played a greater role in promoting biological productivity in the oligotrophic western Pacific Ocean during the LGM than previously realized.

Storms

International Nuclear Information System (INIS)

Kai, Keizo; Melrose, D.B.; Suzuki, S.

1985-01-01

At metre and decametre wavelengths long-lasting solar radio emission, consisting of thousands of short-lived spikes superimposed on a slowly varying continuum, is observed. This type of storm emission may continue for periods ranging from a few hours to several days; the long duration is one of the characteristics which distinguish storms from other types of solar radio emission. These events are called storms or noise storms by analogy with geomagnetic storms. (author)

Dust, Elemental Carbon and Other Impurities on Central Asian Glaciers: Origin and Radiative Forcing

Science.gov (United States)

Schmale, J.; Flanner, M.; Kang, S.; Sprenger, M.; Zhang, Q.; Li, Y.; Guo, J.; Schwikowski, M.

2015-12-01

In Central Asia, more than 60 % of the population depends on water stored in glaciers and mountain snow. While temperature, precipitation and dynamic processes are key drivers of glacial change, deposition of light absorbing impurities such as mineral dust and black carbon can lead to accelerated melting through surface albedo reduction. Here, we discuss the origin of deposited mineral dust and black carbon and their impacts on albedo change and radiative forcing (RF). 218 snow samples were taken from 13 snow pits on 4 glaciers, Abramov (Pamir), Suek, Glacier No. 354 and Golubin (Tien Shan), representing deposition between summer 2012 and 2014. They were analyzed for elemental and organic carbon by a thermo-optical method, mineral dust by gravimetry, and iron by ICP-MS. Back trajectory ensembles were released every 6 hours with the Lagranto model for the covered period at all sites. Boundary layer "footprints" were calculated to estimate general source regions and combined with MODIS fire counts for potential fire contributions. Albedo reduction due to black carbon and mineral dust was calculated with the Snow-Ice-Aerosol-Radiative model (SNICAR), and surface spectral irradiances were derived from atmospheric radiative transfer calculations to determine the RF under clear-sky and all sky conditions using local radiation measurements. Dust contributions came from Central Asia, the Arabian Peninsula, the Sahara and partly the Taklimakan. Fire contributions were higher in 2014 and generally came from the West and North. We find that EC exerts roughly 3 times more RF than mineral dust in fresh and relatively fresh snow (~5 W/m2) and up to 6 times more in snow that experienced melting (> 10 W/m2) even though EC concentrations (average per snow pit from 90 to 700 ng/g) were up to two orders of magnitude lower than mineral dust (10 to 140 μg/g).

Properties of Aerosols during a Dust Storm over the Beijing Area,

Science.gov (United States)

1983-12-12

THE BEIJING AREA by Zhou Mingyu , Qu Shaohou, et al DTIC S ELECTE JAN 04 1984 N Lum E Approved for public release; distribution unlimited. 84 01 04 015...STORM OVER THE BEIJING AREA By: Zhou Mingyu , Qu Shaohou, et al. English~ pages: 22 Source: Huanjing Kexue Xuebao, Vol. 1, Nr. 3, September 1981, pp... Mingyu , Qu Shaohou, Song Ximing, Li Yuying, Yang Shaojin and Qian Qinfang Zhou, Qu, Song and Li of Institute of Atmospheric Physics, Chinese Academy

Occupational dermatoses: An Asian perspective

Directory of Open Access Journals (Sweden)

Riti Bhatia

2017-01-01

Full Text Available Occupational dermatoses contribute to a significant portion of work-related diseases, especially in Asia, where a major portion of the workforce is in the unorganized sector. This review article is focussed on the frequency and pattern of occupational skin diseases reported across Asian countries and type of allergens implicated in different occupations. The literature was searched systematically using key words 'occupational dermatoses,' 'occupational skin disease' and name of each Asian country. Ninty five full-text articles were considered relevant and evaluated. Some of the dermatoses seen in industrial workers in Asian countries are similar to those in Western countries, including dermatoses due to chromate in construction and electroplating workers, epoxy resin, and chromate in painters, wood dust in workers in the furniture industry, azo dyes in textile workers and formaldehyde and chromates in those working in the leather and dyeing industries, dermatoses in domestic workers, chefs and health-care workers. Dermatoses in workers engaged in agriculture, beedi (tiny cigars manufacture, agarbatti (incense sticks production, fish processing, carpet weaving, sanitation and those working in coffee plantations and coal mines appear to be unique to Asian countries. Recognition of clinical patterns and geographic variations in occupational skin diseases will provide an impetus to further strengthen future research in these areas, as well as improving their management.

The DREAMS experiment flown on the ExoMars 2016 mission for the study of Martian environment during the dust storm season

Science.gov (United States)

Bettanini, C.; Esposito, F.; Debei, S.; Molfese, C.; Colombatti, G.; Aboudan, A.; Brucato, J. R.; Cortecchia, F.; di Achille, G.; Guizzo, G. P.; Friso, E.; Ferri, F.; Marty, L.; Mennella, V.; Molinaro, R.; Schipani, P.; Silvestro, S.; Mugnuolo, R.; Pirrotta, S.; Marchetti, E.; International Dreams Team

2018-07-01

The DREAMS (Dust characterization, Risk assessment and Environment Analyser on the Martian Surface) instrument on Schiaparelli lander of ExoMars 2016 mission was an autonomous meteorological station designed to completely characterize the Martian atmosphere on surface, acquiring data not only on temperature, pressure, humidity, wind speed and its direction, but also on solar irradiance, dust opacity and atmospheric electrification; this comprehensive set of parameters would assist the quantification of risks and hazards for future manned exploration missions mainly related to the presence of airborne dust. Schiaparelli landing on Mars was in fact scheduled during the foreseen dust storm season (October 2016 in Meridiani Planum) allowing DREAMS to directly measure the characteristics of such extremely harsh environment. DREAMS instrument’s architecture was based on a modular design developing custom boards for analog and digital channel conditioning, power distribution, on board data handling and communication with the lander. The boards, connected through a common backbone, were hosted in a central electronic unit assembly and connected to the external sensors with dedicated harness. Designed with very limited mass and an optimized energy consumption, DREAMS was successfully tested to operate autonomously, relying on its own power supply, for at least two Martian days (sols) after landing on the planet. A total of three flight models were fully qualified before launch through an extensive test campaign comprising electrical and functional testing, EMC verification and mechanical and thermal vacuum cycling; furthermore following the requirements for planetary protection, contamination control activities and assay sampling were conducted before model delivery for final integration on spacecraft. During the six months cruise to Mars following the successful launch of ExoMars on 14th March 2016, periodic check outs were conducted to verify instrument health check and

Transportation and Bioavailability of Copper and Zinc in a Storm Water Retention Pond

Science.gov (United States)

Camponelli, K.; Casey, R. E.; Wright, M. E.; Lev, S. M.; Landa, E. R.

2006-05-01

Highway runoff has been identified as a non-point source of metals to storm water retention ponds. Zinc and copper are major components of tires and brake pads, respectively. As these automobile parts degrade, they deposit particulates onto the roadway surface. During a storm event, these metal containing particulates are washed into a storm water retention pond where they can then accumulate over time. These metals may be available to organisms inhabiting the pond and surrounding areas. This study focuses on tracking the metals from their deposition on the roadway to their transport and accumulation into a retention pond. The retention pond is located in Owings Mills, MD and collects runoff from an adjacent four lane highway. Pond sediments, background soils, road dust samples, and storm events were collected and analyzed. Copper and zinc concentrations in the pond sediments are higher than local background soils indicating that the pond is storing anthropogenically derived metals. Storm event samples also reveal elevated levels of copper and zinc transported through runoff, along with a large concentration of total suspended solids. After looking at the particulate and dissolved fractions of both metals in the runoff, the majority of the Zn and Cu are in the particulate fraction. Changes in TSS are proportional with changes in particulate bound Zn, indicating that the solid particulates that are entering into the pond are a major contributor of the total metal loading. Sequential extractions carried out on the road dust show that the majority of zinc is extracted in the second and third fractions and could become available to organisms in the pond. There is a small amount of Cu that is being released in the more available stages of the procedure; however the bulk of the Cu is seen in the more recalcitrant steps. In the pond sediments however, both Cu and Zn are only being released from the sediments in the later steps and are most likely not highly available.

Identifying airborne fungi in Seoul, Korea using metagenomics.

Science.gov (United States)

Oh, Seung-Yoon; Fong, Jonathan J; Park, Myung Soo; Chang, Limseok; Lim, Young Woon

2014-06-01

Fungal spores are widespread and common in the atmosphere. In this study, we use a metagenomic approach to study the fungal diversity in six total air samples collected from April to May 2012 in Seoul, Korea. This springtime period is important in Korea because of the peak in fungal spore concentration and Asian dust storms, although the year of this study (2012) was unique in that were no major Asian dust events. Clustering sequences for operational taxonomic unit (OTU) identification recovered 1,266 unique OTUs in the combined dataset, with between 223᾿96 OTUs present in individual samples. OTUs from three fungal phyla were identified. For Ascomycota, Davidiella (anamorph: Cladosporium) was the most common genus in all samples, often accounting for more than 50% of all sequences in a sample. Other common Ascomycota genera identified were Alternaria, Didymella, Khuskia, Geosmitha, Penicillium, and Aspergillus. While several Basidiomycota genera were observed, Chytridiomycota OTUs were only present in one sample. Consistency was observed within sampling days, but there was a large shift in species composition from Ascomycota dominant to Basidiomycota dominant in the middle of the sampling period. This marked change may have been caused by meteorological events. A potential set of 40 allergy-inducing genera were identified, accounting for a large proportion of the diversity present (22.5᾿7.2%). Our study identifies high fungal diversity and potentially high levels of fungal allergens in springtime air of Korea, and provides a good baseline for future comparisons with Asian dust storms.

Collecting Comet Samples by ER-2 Aircraft: Cosmic Dust Collection During the Draconid Meteor Shower in October 2012

Science.gov (United States)

Bastien, Ron; Burkett, P. J.; Rodriquez, M.; Frank, D.; Gonzalez, C.; Robinson, G.-A.; Zolensky, M.; Brown, P.; Campbell-Brown, M.; Broce, S.;

Dust Aerosols at the Source Region During ACE-ASIA: A Surface/Satellite Perspective

Science.gov (United States)

Tsay, Si-Chee; Lau, William K. M. (Technical Monitor)

2001-01-01

ACE (Aerosol Characterization Experiment)-Asia is designed to study the compelling variability in spatial and temporal scale of both pollution-derived and naturally occurring aerosols, which often exist in high concentrations over eastern Asia and along the rim of the western Pacific. The phase-I of ACE-Asia was conducted from March-May 2001 in the vicinity of the Gobi desert, East Coast of China, Yellow Sea, Korea, and Japan, along the pathway of Kosa (severe events that blanket East Asia with yellow desert dust, peaked in the Spring season). Asian dust typically originates in desert areas far from polluted urban regions. During transport, dust layers can interact with anthropogenic sulfate and soot aerosols from heavily polluted urban areas. Added to the complex effects of clouds and natural marine aerosols, dust particles reaching the marine environment can have drastically different properties than those from the source. Thus, understanding the unique temporal and spatial variations of Asian dust is of special importance in regional-to-global climate issues such as radiative forcing, the hydrological cycle, and primary biological productivity in the mid-Pacific Ocean. During ACE-Asia we have measured continuously aerosol physical/optical/radiative properties, column precipitable water amount, and surface reflectivity over homogeneous areas from surface. The inclusion of flux measurements permits the determination of dust aerosol radiative flux in addition to measurements of loading and optical thickness. At the time of the Terra/MODIS, SeaWiFS, TOMS and other satellite overpasses, these ground-based observations can provide valuable data to compare with satellite retrievals over land. Preliminary results will be presented and discussed their implications in regional climatic effects.

Geomagnetically Induced Currents Around the World During the 17 March 2015 Storm

Science.gov (United States)

Carter, B. A.; Yizengaw, E.; Pradipta, R.; Weygand, J. M.; Piersanti, M.; Pulkkinen, Antti Aleksi; Moldwin, M. B.; Norman, R.; Zhang, K.

2016-01-01

Geomagnetically induced currents (GICs) represent a significant space weather issue for power grid and pipeline infrastructure, particularly during severe geomagnetic storms. In this study, magnetometer data collected from around the world are analyzed to investigate the GICs caused by the 2015 St. Patricks Day storm. While significant GIC activity in the high-latitude regions due to storm time substorm activity is shown for this event, enhanced GIC activity was also measured at two equatorial stations in the American and Southeast Asian sectors. This equatorial GIC activity is closely examined, and it is shown that it is present both during the arrival of the interplanetary shock at the storm sudden commencement (SSC) in Southeast Asia and during the main phase of the storm approximately 10 h later in South America. The SSC caused magnetic field variations at the equator in Southeast Asia that were twice the magnitude of those observed only a few degrees to the north, strongly indicating that the equatorial electrojet (EEJ) played a significant role. The large equatorial magnetic field variations measured in South America are also examined, and the coincident solar wind data are used to investigate the causes of the sudden changes in the EEJ approximately 10 h into the storm. From this analysis it is concluded that sudden magnetopause current increases due to increases in the solarwind dynamic pressure, and the sudden changes in the resultant magnetospheric and ionospheric current systems, are the primary drivers of equatorial GICs.

Origin of pollutants in South Asia

International Nuclear Information System (INIS)

Siddique, N.; Waheed, S.

2012-01-01

Transboundary transport of air pollution in the South Asian region has been an issue of increasing importance over the past several decades. Long-range transport of pollution produced by natural processes such as dust storms or natural forest fires. Airborne particulate matter datasets covering the period from 2002 to 2007 from the neighbouring countries like Bangladesh, India, Pakistan and Sri Lanka were used to find the source areas that are primarily responsible for long range transported pollutants. All countries collected samples with the same type of sampler and used the same techniques for mass and BC measurements. It was found that high fine soil contributions were from dust storms. On the other hand smoke in this region mainly comes from Northern India where agricultural waste is often burned is shown. (Orig./A.B.)

Dust Generation Resulting from Desiccation of Playa Systems: Studies on Mono and Owens Lakes, California

Science.gov (United States)

Gill, Thomas Edward

1995-01-01

Playas, evaporites, and aeolian sediments frequently are linked components within the Earth system. Anthropogenic water diversions from terminal lakes form playas that release fugitive dust. These actions, documented worldwide, simulate aeolian processes activated during palaeoclimatic pluvial/interpluvial transitions, and have significant environmental impacts. Pluvial lakes Russell and Owens in North America's Great Basin preceded historic Mono and Owens Lakes, now desiccated by water diversions into dust-generating, evaporite -encrusted playas. Geochemical and hydrologic cycles acting on the Owens (Dry) Lake playa form three distinct crust types each year. Although initial dust production results from deflation of surface efflorescences after the playa dries, most aerosols are created by saltation abrasion of salt/silt/clay crusts at crust/ sand sheet contacts. The warm-season, clastic "cemented" crust is slowest to degrade into dust. If the playa surface is stabilized by an unbroken, non-efflorescent crust, dust formation is discouraged. When Mono Lake's surFace elevation does not exceed 1951 meters (6400 feet), similar processes will also generate dust from its saline lower playa. Six factors--related to wind, topography, groundwater, and sediments--control dust formation at both playas. These factors were combined into a statistical model relating suspended dust concentrations to playa/lake morphometry. The model shows the extent and severity of Mono Lake dust storms expands significantly below the surface level 6376 feet (1943.5 meters). X-ray diffraction analysis of Mono Basin soils, playa sediments, and aerosols demonstrates geochemical cycling of materials through land, air and water during Mono Lake's 1982 low stand. Soils and clastic playa sediments contain silicate minerals and tephra. Saline groundwater deposited calcite, halite, thenardite, gaylussite, burkeite and glauberite onto the lower playa. Aerosols contained silicate minerals (especially

Optical and microphysical properties of natural mineral dust and anthropogenic soil dust near dust source regions over northwestern China

Directory of Open Access Journals (Sweden)

X. Wang

2018-02-01

Full Text Available Mineral dust aerosols (MDs not only influence the climate by scattering and absorbing solar radiation but also modify cloud properties and change the ecosystem. From 3 April to 16 May 2014, a ground-based mobile laboratory was deployed to measure the optical and microphysical properties of MDs near dust source regions in Wuwei, Zhangye, and Dunhuang (in chronological order along the Hexi Corridor over northwestern China. Throughout this dust campaign, the hourly averaged (±standard deviation aerosol scattering coefficients (σsp, 550 nm of the particulates with aerodynamic diameters less than 2.5 µm (PM2.5 at these three sites were sequentially 101.5 ± 36.8, 182.2 ± 433.1, and 54.0 ± 32.0 Mm−1. Correspondingly, the absorption coefficients (σap, 637 nm were 9.7 ± 6.1, 6.0 ± 4.6, and 2.3 ± 0.9 Mm−1; single-scattering albedos (ω, 637 nm were 0.902 ± 0.025, 0.931 ± 0.037, and 0.949 ± 0.020; and scattering Ångström exponents (Åsp, 450–700 nm of PM2.5 were 1.28 ± 0.27, 0.77 ± 0.51, and 0.52 ± 0.31. During a severe dust storm in Zhangye (i.e., from 23 to 25 April, the highest values of σsp2.5 ( ∼  5074 Mm−1, backscattering coefficient (σbsp2.5,  ∼  522 Mm−1, and ω637 ( ∼  0.993 and the lowest values of backscattering fraction (b2.5,  ∼  0.101 at 550 nm and Åsp2.5 ( ∼  −0.046 at 450–700 nm, with peak values of aerosol number size distribution (appearing at the particle diameter range of 1–3 µm, exhibited that the atmospheric aerosols were dominated by coarse-mode dust aerosols. It is hypothesized that the relatively higher values of mass scattering efficiency during floating dust episodes in Wuwei and Zhangye are attributed to the anthropogenic soil dust produced by agricultural cultivations.

Effect of chemical mixing state on the hygroscopicity and cloud nucleation properties of calcium mineral dust particles

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R. C. Sullivan

2009-05-01

Full Text Available Atmospheric mineral dust particles can alter cloud properties and thus climate by acting as cloud condensation nuclei (CCN that form cloud droplets. The CCN activation properties of various calcium mineral dust particles were studied experimentally to investigate the consequences of field observations showing the segregation of sulphate from nitrate and chloride between individual aged Asian dust particles, and the enrichment of oxalic acid in Asian dust. Each mineral's observed apparent hygroscopicity was primarily controlled by its solubility, which determines the degree to which the mineral's intrinsic hygroscopicity can be expressed. The significant increase in hygroscopicity caused by mixing soluble hygroscopic material with insoluble mineral particles is also presented. Insoluble minerals including calcium carbonate, representing fresh unprocessed dust, and calcium sulphate, representing atmospherically processed dust, had similarly small apparent hygroscopicities. Their activation is accurately described by a deliquescence limit following the Kelvin effect and corresponded to an apparent single-hygroscopicity parameter, κ, of ~0.001. Soluble calcium chloride and calcium nitrate, representing atmospherically processed mineral dust particles, were much more hygroscopic, activating similar to ammonium sulphate with κ~0.5. Calcium oxalate monohydrate (κ=0.05 was significantly less CCN-active than oxalic acid (κ=0.3, but not as inactive as its low solubility would predict. These results indicate that the common assumption that all mineral dust particles become more hygroscopic and CCN-active after atmospheric processing should be revisited. Calcium sulphate and calcium oxalate are two realistic proxies for aged mineral dust that remain non-hygroscopic. The dust's apparent hygroscopicity will be controlled by its chemical mixing state, which is determined by its mineralogy and the chemical reaction pathways it experiences

Climatic controls of the interannual to decadal variability in Saudi Arabian dust activity: Towards the development of a seasonal prediction tool

Science.gov (United States)

Yu, Y.; Notaro, M.; Liu, Z.; Alkolibi, F.; Fadda, E.; Bakhrjy, F.

2013-12-01

Atmospheric dust significantly influences the climate system, as well as human life in Saudi Arabia. Skillful seasonal prediction of dust activity with climatic variables will help prevent some negative social impacts of dust storms. Yet, the climatic regulators on Saudi Arabian dust activity remain largely unaddressed. Remote sensing and station observations show consistent seasonal cycles in Saudi Arabian dust activity, which peaks in spring and summer. The climatic controls on springtime and summertime Saudi Arabian dust activity during 1975-2010 are studied using observational and reanalysis data. Empirical Orthogonal Function (EOF) of the observed Saudi Arabian dust storm frequency shows a dominant homogeneous pattern across the country, which has distinct interannual and decadal variations, as revealed by the power spectrum. Regression and correlation analyses reveal that Saudi Arabian dust activity is largely tied to precipitation on the Arabian Peninsula in spring and northwesterly (Shamal) wind in summer. On the seasonal-interannual time scale, warm El Niño-Southern Oscillation (ENSO) phase (El Niño) in winter-to-spring inhibits spring dust activity by increasing the precipitation over the Rub'al Khali Desert, a major dust source region on the southern Arabian Peninsula; warm ENSO and warm Indian Ocean Basin Mode (IOBM) in winter-to-spring favor less summer dust activity by producing anomalously low sea-level pressure over eastern north Africa and Arabian Peninsula, which leads to the reduced Shamal wind speed. The decadal variation in dust activity is likely associated with the Atlantic Multidecadal Oscillation (AMO), which impacts Sahel rainfall and North African dust, and likely dust transport to Saudi Arabia. The Pacific Decadal Oscillation (PDO) and tropical Indian Ocean SST also have influence on the decadal variation in Saudi Arabian dust activity, by altering precipitation over the Arabian Peninsula and summer Shamal wind speed. Using eastern

Ice nucleation by surrogates for atmospheric mineral dust and mineral dust/sulfate particles at cirrus temperatures

Directory of Open Access Journals (Sweden)

C. M. Archuleta

2005-01-01

Full Text Available This study examines the potential role of some types of mineral dust and mineral dust with sulfuric acid coatings as heterogeneous ice nuclei at cirrus temperatures. Commercially-available nanoscale powder samples of aluminum oxide, alumina-silicate and iron oxide were used as surrogates for atmospheric mineral dust particles, with and without multilayer coverage of sulfuric acid. A sample of Asian dust aerosol particles was also studied. Measurements of ice nucleation were made using a continuous-flow ice-thermal diffusion chamber (CFDC operated to expose size-selected aerosol particles to temperatures between -45 and -60°C and a range of relative humidity above ice-saturated conditions. Pure metal oxide particles supported heterogeneous ice nucleation at lower relative humidities than those required to homogeneously freeze sulfuric acid solution particles at sizes larger than about 50 nm. The ice nucleation behavior of the same metal oxides coated with sulfuric acid indicate heterogeneous freezing at lower relative humidities than those calculated for homogeneous freezing of the diluted particle coatings. The effect of soluble coatings on the ice activation relative humidity varied with the respective uncoated core particle types, but for all types the heterogeneous freezing rates increased with particle size for the same thermodynamic conditions. For a selected size of 200 nm, the natural mineral dust particles were the most effective ice nuclei tested, supporting heterogeneous ice formation at an ice relative humidity of approximately 135%, irrespective of temperature. Modified homogeneous freezing parameterizations and theoretical formulations are shown to have application to the description of heterogeneous freezing of mineral dust-like particles with soluble coatings.

Optical Extinction Measurements of Dust Density in the GMRO Regolith Test Bin

Science.gov (United States)

Lane, J.; Mantovani, J.; Mueller, R.; Nugent, M.; Nick, A.; Schuler, J.; Townsend, I.

2016-01-01

A regolith simulant test bin was constructed and completed in the Granular Mechanics and Regolith Operations (GMRO) Lab in 2013. This Planetary Regolith Test Bed (PRTB) is a 64 sq m x 1 m deep test bin, is housed in a climate-controlled facility, and contains 120 MT of lunar-regolith simulant, called Black Point-1 or BP-1, from Black Point, AZ. One of the current uses of the test bin is to study the effects of difficult lighting and dust conditions on Telerobotic Perception Systems to better assess and refine regolith operations for asteroid, Mars and polar lunar missions. Low illumination and low angle of incidence lighting pose significant problems to computer vision and human perception. Levitated dust on Asteroids interferes with imaging and degrades depth perception. Dust Storms on Mars pose a significant problem. Due to these factors, the likely performance of telerobotics is poorly understood for future missions. Current space telerobotic systems are only operated in bright lighting and dust-free conditions. This technology development testing will identify: (1) the impact of degraded lighting and environmental dust on computer vision and operator perception, (2) potential methods and procedures for mitigating these impacts, (3) requirements for telerobotic perception systems for asteroid capture, Mars dust storms and lunar regolith ISRU missions. In order to solve some of the Telerobotic Perception system problems, a plume erosion sensor (PES) was developed in the Lunar Regolith Simulant Bin (LRSB), containing 2 MT of JSC-1a lunar simulant. PES is simply a laser and digital camera with a white target. Two modes of operation have been investigated: (1) single laser spot - the brightness of the spot is dependent on the optical extinction due to dust and is thus an indirect measure of particle number density, and (2) side-scatter - the camera images the laser from the side, showing beam entrance into the dust cloud and the boundary between dust and void. Both

Phytoplankton growth response to Asian dust addition in the northwest Pacific Ocean versus the Yellow Sea

Science.gov (United States)

Zhang, Chao; Gao, Huiwang; Yao, Xiaohong; Shi, Zongbo; Shi, Jinhui; Yu, Yang; Meng, Ling; Guo, Xinyu

2018-02-01

In this study, five on-board microcosm experiments were performed in the subtropical gyre, the Kuroshio Extension region of the northwest Pacific Ocean (NWPO), and the Yellow Sea (YS) in order to investigate phytoplankton growth following the addition of artificially modified mineral dust (AM dust) and various nutrients (nitrogen (N), phosphorus (P), iron (Fe), N + P, and N + P + Fe). The two experiments carried out with AM-dust addition in the subtropical gyre showed a maximum chlorophyll a (Chl a) concentration increase of 1.7- and 2.8-fold, while the cell abundance of large-sized phytoplankton ( > 5 µm) showed a 1.8- and 3.9-fold increase, respectively, relative to the controls. However, in the Kuroshio Extension region and the YS, the increases in maximum Chl a and cell abundance of large-sized phytoplankton following AM-dust addition were at most 1.3-fold and 1.7-fold larger than those in the controls, respectively. A net conversion efficiency index (NCEI) newly proposed in this study, size-fractionated Chl a, and the abundance of large-sized phytoplankton were analysed to determine which nutrients contribute to supporting phytoplankton growth. Our results demonstrate that a combination of nutrients, N-P or N + P + Fe, is responsible for phytoplankton growth in the subtropical gyre following AM-dust addition. Single nutrient addition, i.e., N in the Kuroshio Extension region and P or N in the YS, controls the phytoplankton growth following AM-dust addition. In the AM-dust-addition experiments, in which the increased N-P or P was identified to determine phytoplankton growth, the dissolved inorganic P from AM dust (8.6 nmol L-1) was much lower than the theoretically estimated minimum P demand (˜ 20 nmol L-1) for phytoplankton growth. These observations suggest that additional supply augments the bioavailable P stock in incubated seawater with AM-dust addition, most likely due to an enhanced solubility of P from AM dust or the remineralization of the dissolved

Electrodynamic Dust Shield Demonstrator

Science.gov (United States)

Stankie, Charles G.

2013-01-01

The objective of the project was to design and manufacture a device to demonstrate a new technology developed by NASA's Electrostatics and Surface Physics Laboratory. The technology itself is a system which uses magnetic principles to remove regolith dust from its surface. This project was to create an enclosure that will be used to demonstrate the effectiveness of the invention to The Office of the Chief Technologist. ONE of the most important challenges of space exploration is actually caused by something very small and seemingly insignificant. Dust in space, most notably on the moon and Mars, has caused many unforeseen issues. Dirt and dust on Earth, while a nuisance, can be easily cleaned and kept at bay. However, there is considerably less weathering and erosion in space. As a result, the microscopic particles are extremely rough and abrasive. They are also electrostatically charged, so they cling to everything they make contact with. This was first noted to be a major problem during the Apollo missions. Dust would stick to the spacesuits, and could not be wiped off as predicted. Dust was brought back into the spacecraft, and was even inhaled by astronauts. This is a major health hazard. Atmospheric storms and other events can also cause dust to coat surfaces of spacecraft. This can cause abrasive damage to the craft. The coating can also reduce the effectiveness of thermal insulation and solar panels.' A group of engineers at Kennedy Space Center's Electrostatics and Surface Physics Laboratory have developed a new technology, called the Electrodynamic Dust Shield, to help alleviate these problems. It is based off of the electric curtain concept developed at NASA in 1967. "The EDS is an active dust mitigation technology that uses traveling electric fields to transport electrostatically charged dust particles along surfaces. To generate the traveling electric fields, the EDS consists of a multilayer dielectric coating with an embedded thin electrode grid

[Process study on hysteresis of vegetation cover influencing sand-dust events].

Science.gov (United States)

Xu, Xing-Kui; Wang, Xiao-Tao; Zhang, Feng

2009-02-15

Data analysis from satellite and weather stations during 1982-2000 shows nonlinear relationship between vegetation cover and sand-dust events is present in most part of China. Vegetation cover ratio in summer can impact significantly on the frequency of sand-dust storms from winter to spring in the source regions of sand-dust events. It is not quite clear about the hysteresis that vegetation cover in summer influence sand-dust events during winter and spring. A quasi-geostrophic barotropic model is used under the condition of 3 magnitude of frictional coefficient to investigate the cause of the hysteresis. Wind velocity shows a greatest decline at 90% during 72 h as initial wind velocity is 10 m/s for magnitude of frictional coefficient between atmosphere and water surface, greatest decline at 100% during 18 h for magnitude of frictional coefficient between atmosphere and bare soil and a 100% reduction of wind speed during 1 h for magnitude of frictional coefficient between atmosphere and vegetation cover. Observation and simulation prove that residual root and stem from summervegetation are one of factors to influence sand-dust events happened during winter and spring. Air inhibition from residual root and stem is a most important reason for hysteresis that vegetation cover influence sand-dust events.

An overview of mineral dust modeling over East Asia

Science.gov (United States)

Chen, Siyu; Huang, Jianping; Qian, Yun; Zhao, Chun; Kang, Litai; Yang, Ben; Wang, Yong; Liu, Yuzhi; Yuan, Tiangang; Wang, Tianhe; Ma, Xiaojun; Zhang, Guolong

2017-08-01

East Asian dust (EAD) exerts considerable impacts on the energy balance and climate/climate change of the earth system through its influence on solar and terrestrial radiation, cloud properties, and precipitation efficiency. Providing an accurate description of the life cycle and climate effects of EAD is therefore critical to better understanding of climate change and socioeconomic development in East Asia and even worldwide. Dust modeling has undergone substantial development since the late 1990s, associated with improved understanding of the role of EAD in the earth system. Here, we review the achievements and progress made in recent decades in terms of dust modeling research, including dust emissions, long-range transport, radiative forcing (RF), and climate effects of dust particles over East Asia. Numerous efforts in dust/EAD modeling have been directed towards furnishing more sophisticated physical and chemical processes into the models on higher spatial resolutions. Meanwhile, more systematic observations and more advanced retrieval methods for instruments that address EAD related science issues have made it possible to evaluate model results and quantify the role of EAD in the earth system, and to further reduce the uncertainties in EAD simulations. Though much progress has been made, large discrepancies and knowledge gaps still exist among EAD simulations. The deficiencies and limitations that pertain to the performance of the EAD simulations referred to in the present study are also discussed.

Systematic characterization of structural, dynamical and electrical properties of dust devils and implications for dust lifting processes

Science.gov (United States)

Franzese, Gabriele; Esposito, Francesca; Lorenz, Ralph D.; Popa, Ciprian; Silvestro, Simone; Deniskina, Natalia; Cozzolino, Fabio

2017-04-01

scale. Instead, on Mars the presence of the dust devils has been confirmed at almost every latitude and altitude and it has been indicated as the possible main source of suspended dust outside the storm seasons. Hence, the study of the dust devils becomes of great importance in order to understand the atmospheric dust loading and the global climate of the planet. In addition, the dust lifting phenomena are probably one of the main source of atmospheric electrification on Mars and the measurement and study of the Martian boundary layer electric field is one of the main objectives of the future Martian space missions, such as ExoMars 2020. Indeed, this mission will accommodate "Dust Complex", a suite of sensors that will monitor lifted dust and atmospheric electric field on the surface of Mars. For these reasons, the present work represents a useful tool for the understanding of the dust lifting phenomena and their electrification both on Earth and on Mars.

Bioprocess of Kosa bioaerosols: effect of ultraviolet radiation on airborne bacteria within Kosa (Asian dust).

Science.gov (United States)

Kobayashi, Fumihisa; Maki, Teruya; Kakikawa, Makiko; Yamada, Maromu; Puspitasari, Findya; Iwasaka, Yasunobu

2015-05-01

Kosa (Asian dust) is a well-known weather phenomenon in which aerosols are carried by the westerly winds from inland China to East Asia. Recently, the frequency of this phenomenon and the extent of damage caused have been increasing. The airborne bacteria within Kosa are called Kosa bioaerosols. Kosa bioaerosols have affected ecosystems, human health and agricultural productivity in downwind areas. In order to develop a new and useful bacterial source and to identify the source region of Kosa bioaerosols, sampling, isolation, identification, measurement of ultraviolet (UV) radiation tolerance and experimental simulation of UV radiation conditions were performed during Kosa bioaerosol transportation. We sampled these bioaerosols using a Cessna 404 airplane and a bioaerosol sampler at an altitude of approximately 2900 m over the Noto Peninsula on March 27, 2010. The bioaerosol particles were isolated and identified as Bacillus sp. BASZHR 1001. The results of the UV irradiation experiment showed that the UV radiation tolerance of Kosa bioaerosol bacteria was very high compared with that of a soil bacterium. Moreover, the UV radiation tolerance of Kosa bioaerosol spores was higher than that of soil bacterial spores. This suggested that Kosa bioaerosols are transported across the atmosphere as living spores. Similarly, by the experimental simulation of UV radiation conditions, the limited source region of this Kosa bioaerosol was found to be southern Russia and there was a possibility of transport from the Kosa source area. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Modulation of ice ages via precession and dust-albedo feedbacks

Directory of Open Access Journals (Sweden)

Ralph Ellis

2016-11-01

Full Text Available We present here a simple and novel proposal for the modulation and rhythm of ice-ages and interglacials during the late Pleistocene. While the standard Milankovitch-precession theory fails to explain the long intervals between interglacials, these can be accounted for by a novel forcing and feedback system involving CO2, dust and albedo. During the glacial period, the high albedo of the northern ice sheets drives down global temperatures and CO2 concentrations, despite subsequent precessional forcing maxima. Over the following millennia more CO2 is sequestered in the oceans and atmospheric concentrations eventually reach a critical minima of about 200 ppm, which combined with arid conditions, causes a die-back of temperate and boreal forests and grasslands, especially at high altitude. The ensuing soil erosion generates dust storms, resulting in increased dust deposition and lower albedo on the northern ice sheets. As northern hemisphere insolation increases during the next Milankovitch cycle, the dust-laden ice-sheets absorb considerably more insolation and undergo rapid melting, which forces the climate into an interglacial period. The proposed mechanism is simple, robust, and comprehensive in its scope, and its key elements are well supported by empirical evidence.

Microarray Analysis of Gene Expression Alteration in Human Middle Ear Epithelial Cells Induced by Asian Sand Dust.

Science.gov (United States)

Go, Yoon Young; Park, Moo Kyun; Kwon, Jee Young; Seo, Young Rok; Chae, Sung-Won; Song, Jae-Jun

2015-12-01

The primary aim of this study is to evaluate the gene expression profile of Asian sand dust (ASD)-treated human middle ear epithelial cell (HMEEC) using microarray analysis. The HMEEC was treated with ASD (400 µg/mL) and total RNA was extracted for microarray analysis. Molecular pathways among differentially expressed genes were further analyzed. For selected genes, the changes in gene expression were confirmed by real-time polymerase chain reaction. A total of 1,274 genes were differentially expressed by ASD. Among them, 1,138 genes were 2 folds up-regulated, whereas 136 genes were 2 folds down-regulated. Up-regulated genes were mainly involved in cellular processes, including apoptosis, cell differentiation, and cell proliferation. Down-regulated genes affected cellular processes, including apoptosis, cell cycle, cell differentiation, and cell proliferation. The 10 genes including ADM, CCL5, EDN1, EGR1, FOS, GHRL, JUN, SOCS3, TNF, and TNFSF10 were identified as main modulators in up-regulated genes. A total of 11 genes including CSF3, DKK1, FOSL1, FST, TERT, MMP13, PTHLH, SPRY2, TGFBR2, THBS1, and TIMP1 acted as main components of pathway associated with 2-fold down regulated genes. We identified the differentially expressed genes in ASD-treated HMEEC. Our work indicates that air pollutant like ASD, may play an important role in the pathogenesis of otitis media.

Effects of dust on forest tree health in Zagros oak forests.

Science.gov (United States)

Moradi, A; Taheri Abkenar, K; Afshar Mohammadian, M; Shabanian, N

2017-10-10

Dust is one of the most devastating factors for the environment threatening all animal and plant species. In many regions, the ecological and economic impact of microdust on scarce species is critical. In the western region of Iran, the Zagros forests have been exposed to dust storms for many years. In this study, the effect of dust on oak trees, the most important trees of Zagros forests, is investigated. For this purpose, 3-year-old seedlings of three species of oak trees under natural conditions were exposed to dust during spring and summer months. Seedlings were divided into two groups; one group was assigned as dust treatment and the other as control that the control group washed regularly to remove dust. Anatomical characteristics of leaves and dust deposits on leaves during the study period were examined by scanning electron microscope (SEM). The rate of photosynthesis and gas exchange in control and treated plants was examined by IRGA, LCI. SEM images showed that stomata structure, trichome density, and epicuticular waxes of leaves are different in all three species. This difference in micromorphology of species influences the effects of dust deposited on the leaves. A comparison of leaf species images in control and dust treatment showed that in dust treatment the percentage of stomata blocked by dust in three species (per unit area) of Quercus infectoria, Q. libni, and Q. brantii were 61/6, 48/4, and 38/1%, respectively. The results of leaf gas exchange investigation indicated that stomatal occlusion by dust had a negative impact on the examined parameters of three oak species (P ≤ 0.01). Thus, gas exchange and photosynthetic rates of the treated species were significantly reduced. The results of both parts of the study showed the vulnerability of the three species to dust as Q. infectoria > Q. libni > Q. brantii. Therefore, based on these findings, dust can disrupt the physiological activities of the studied species and the continuation of the

Atmospheric dust events in central Asia: Relationship to wind, soil type, and land use

Science.gov (United States)

Pi, Huawei; Sharratt, Brenton; Lei, Jiaqiang

2017-06-01

Xinjiang Province in northwest China is one of the most important source regions of atmospheric dust in the world. Spatial-temporal characteristics of dust events in the province were investigated by time series analysis of annual dust event frequency and meteorological data collected at 101 meteorological stations from 1960 to 2007. Blowing dust frequency (BDF) and dust storm frequency (DSF) decreased with time in North, South, and East Xinjiang whereas floating dust frequency (FDF) decreased with time only in South and East Xinjiang. Dust concentrations were lower in North than in South Xinjiang and decreased with time in East Xinjiang. Wind significantly influenced the temporal trend in FDF, BDF, and DSF in South Xinjiang and DSF in North Xinjiang. Frequency of dust events was smaller by an order of magnitude in North (10.9 d yr-1) than in South Xinjiang (111.3 d yr-1), possibly due in part to higher annual precipitation in North Xinjiang. Floating dust was most frequently observed in East and South Xinjiang, while blowing dust was most frequently observed in North Xinjiang. The high frequency of floating dust in East and South Xinjiang is likely due to the enclosed terrain that characterizes these regions. Land use and soil type also influenced dust events. Although climate influences frequency of dust events, the occurrence of these events may be reduced most effectively by imposing better land management practices in deciduous forests or orchards characterized by saline soils in respectively North and East Xinjiang and meadows characterized by Guanyu soils in South Xinjiang.

The effects of electric forces on dust lifting: Preliminary studies with a numerical model

International Nuclear Information System (INIS)

Kok, J F; Renno, N O

2008-01-01

Atmospheric dust aerosols affect the Earth's climate by scattering and absorbing radiation and by modifying cloud properties. Recent experiments have indicated that electric fields produced in dusty phenomena such as dust storms and dust devils could enhance the emission of dust aerosols. However, the generation of electric fields in dusty phenomena is poorly understood. To address this problem, we present results from the first physically-based numerical model of electric fields in dust lifting. Our model calculates the motion and collisions of air-borne particles, as well as the charge transfer during these collisions. This allows us to simulate the formation of electric fields as a function of physical parameters, such as wind stress and soil properties. Preliminary model results show that electric fields can indeed enhance the lifting of soil particles. Moreover, they suggest that strong electric fields could trigger a positive feedback because increases in the concentration of charged particles strengthen the original electric field, which in turn lifts additional surface particles. We plan to further test and calibrate our model with experimental data.

Dust Propagation and Radiation In the Presence of a Low-level Jet in Central China on March 17, 2010

Science.gov (United States)

McDowell, B. K.; Chen, S. H.

2014-12-01

Suspended dust in the air can directly change the energy budget in the atmosphere and at the surface through scattering and absorption of radiation. Thus, dust can potentially modify the development of weather systems. To explore the dust-radiation effects on weather systems, a dust model was developed based on the Weather Research and Forecasting (WRF) model. The calculations of dust processes in the WRF dust model include emission, advection, boundary layer mixing, cumulus mixing, dust-radiation interaction, wet scavenging, and sedimentation. Due to a high vertical spatial resolution near the surface a time splitting method was applied to the calculation of dust sedimentation to relax the numerical time step. The "Hexi Corridor" is the historical name given to a string of oases along the northern slope of the Tibetan Plateau that formed a relatively easy transportation route between eastern China and central Asia. As trade developed over the centuries, this route became known as the Silk Road. This corridor also marks the transition from the relatively flat Gobi desert area in northern China to the elevated mountains of the Tibetan Plateau. These mountains present a southern barrier to the paths of dust storms that develop during spring outbreaks of the Mongolian Cyclone. In March of 2010, a series of dust storms developed in the Gobi Desert north of the Hexi Corridor that transported massive amounts of dust eastward to central and northeastern China, Korea and Japan. On March 17 during this event, a low-level jet developed along the northern perimeter of the Plateau, in alignment with upper level winds and the Hexi Corridor. Over the course of the day, a well-defined short-duration dust plume was emitted in the southern Gobi desert area and was transported over 1300 km in a southeast direction, over the Loess Plateau and into the Gansu Province. In this study, the interactions of synoptic conditions with regional topography that led to the development of the low

Optical properties of dust and the opacity of the Martian atmosphere

Science.gov (United States)

Korablev, O.; Moroz, V. I.; Petrova, E. V.; Rodin, A. V.

Particulate component of the Mars atmosphere composed by micron-sized products of soil weathering and water ice clouds strongly affects the current climate of the planet. In the absence of a dust storm so-called permanent dust haze with τ ≈ 0.2 in the atmosphere of Mars determines its thermal structure. Dust loading varies substantially with the season and geographic location, and only the data of mapping instruments are adequate to characterize it, such as TES/MGS and IRTM/Viking. In spite of vast domain of collected data, no model is now capable to explain all observed spectral features of dust aerosol. Several mineralogical and microphysical models of the atmospheric dust have been proposed but they cannot explain the pronounced systematic differences between the IR data (τ = 0.05-0.2) and measurements from the surface (Viking landers, Pathfinder) which give the typical “clear” optical depth of τ ≈ 0.5 from one side, and ground-based observations in the UV-visible range showing much more transparent atmosphere, on the other side. Also the relationship between τ9 and the visible optical depth is not well constrained experimentally so far. Future focused measurements are therefore necessary to study Martian aerosol.

Storm Time Global Observations of Large-Scale TIDs From Ground-Based and In Situ Satellite Measurements

Science.gov (United States)

Habarulema, John Bosco; Yizengaw, Endawoke; Katamzi-Joseph, Zama T.; Moldwin, Mark B.; Buchert, Stephan

2018-01-01

This paper discusses the ionosphere's response to the largest storm of solar cycle 24 during 16-18 March 2015. We have used the Global Navigation Satellite Systems (GNSS) total electron content data to study large-scale traveling ionospheric disturbances (TIDs) over the American, African, and Asian regions. Equatorward large-scale TIDs propagated and crossed the equator to the other side of the hemisphere especially over the American and Asian sectors. Poleward TIDs with velocities in the range ≈400-700 m/s have been observed during local daytime over the American and African sectors with origin from around the geomagnetic equator. Our investigation over the American sector shows that poleward TIDs may have been launched by increased Lorentz coupling as a result of penetrating electric field during the southward turning of the interplanetary magnetic field, Bz. We have observed increase in SWARM satellite electron density (Ne) at the same time when equatorward large-scale TIDs are visible over the European-African sector. The altitude Ne profiles from ionosonde observations show a possible link that storm-induced TIDs may have influenced the plasma distribution in the topside ionosphere at SWARM satellite altitude.

African dust carries microbes across the ocean: are they affecting human and ecosystem health?

Science.gov (United States)

Kellogg, Christina A.; Griffin, Dale W.

2003-01-01

Atmospheric transport of dust from northwest Africa to the western Atlantic Ocean region may be responsible for a number of environmental hazards, including the demise of Caribbean corals; red tides; amphibian diseases; increased occurrence of asthma in humans; and oxygen depletion (eutrophication) in estuaries. Studies of satellite images suggest that hundreds of millions of tons of dust are trans-ported annually at relatively low altitudes across the Atlantic Ocean to the Caribbean Sea and southeastern United States. The dust emanates from the expanding Sahara/Sahel desert region in Africa and carries a wide variety of bacteria and fungi. The U.S. Geological Survey, in collaboration with the NASA/Goddard Spaceflight Center, is conducting a study to identify microbes--bacteria, fungi, viruses--transported across the Atlantic in African soil dust. Each year, millions of tons of desert dust blow off the west African coast and ride the trade winds across the ocean, affecting the entire Caribbean basin, as well as the southeastern United States. Of the dust reaching the U.S., Florida receives about 50 percent, while the rest may range as far north as Maine or as far west as Colorado. The dust storms can be tracked by satellite and take about one week to cross the Atlantic.

Geomagnetic storm forecasting service StormFocus: 5 years online

Science.gov (United States)

Podladchikova, Tatiana; Petrukovich, Anatoly; Yermolaev, Yuri

2018-04-01

Forecasting geomagnetic storms is highly important for many space weather applications. In this study, we review performance of the geomagnetic storm forecasting service StormFocus during 2011-2016. The service was implemented in 2011 at SpaceWeather.Ru and predicts the expected strength of geomagnetic storms as measured by Dst index several hours ahead. The forecast is based on L1 solar wind and IMF measurements and is updated every hour. The solar maximum of cycle 24 is weak, so most of the statistics are on rather moderate storms. We verify quality of selection criteria, as well as reliability of real-time input data in comparison with the final values, available in archives. In real-time operation 87% of storms were correctly predicted while the reanalysis running on final OMNI data predicts successfully 97% of storms. Thus the main reasons for prediction errors are discrepancies between real-time and final data (Dst, solar wind and IMF) due to processing errors, specifics of datasets.

Solar noise storms

CERN Document Server

Elgaroy, E O

2013-01-01

Solar Noise Storms examines the properties and features of solar noise storm phenomenon. The book also presents some theories that can be used to gain a better understanding of the phenomenon. The coverage of the text includes topics that cover the features and behavior of noise storms, such as the observable features of noise storms; the relationship between noise storms and the observable features on the sun; and ordered behavior of storm bursts in the time-frequency plane. The book also covers the spectrum, polarization, and directivity of noise storms. The text will be of great use to astr

Empirical STORM-E Model. [I. Theoretical and Observational Basis

Science.gov (United States)

Mertens, Christopher J.; Xu, Xiaojing; Bilitza, Dieter; Mlynczak, Martin G.; Russell, James M., III

2013-01-01

Auroral nighttime infrared emission observed by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument onboard the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) satellite is used to develop an empirical model of geomagnetic storm enhancements to E-region peak electron densities. The empirical model is called STORM-E and will be incorporated into the 2012 release of the International Reference Ionosphere (IRI). The proxy for characterizing the E-region response to geomagnetic forcing is NO+(v) volume emission rates (VER) derived from the TIMED/SABER 4.3 lm channel limb radiance measurements. The storm-time response of the NO+(v) 4.3 lm VER is sensitive to auroral particle precipitation. A statistical database of storm-time to climatological quiet-time ratios of SABER-observed NO+(v) 4.3 lm VER are fit to widely available geomagnetic indices using the theoretical framework of linear impulse-response theory. The STORM-E model provides a dynamic storm-time correction factor to adjust a known quiescent E-region electron density peak concentration for geomagnetic enhancements due to auroral particle precipitation. Part II of this series describes the explicit development of the empirical storm-time correction factor for E-region peak electron densities, and shows comparisons of E-region electron densities between STORM-E predictions and incoherent scatter radar measurements. In this paper, Part I of the series, the efficacy of using SABER-derived NO+(v) VER as a proxy for the E-region response to solar-geomagnetic disturbances is presented. Furthermore, a detailed description of the algorithms and methodologies used to derive NO+(v) VER from SABER 4.3 lm limb emission measurements is given. Finally, an assessment of key uncertainties in retrieving NO+(v) VER is presented

Paradigm shifts about dust on the Moon: From Apollo 11 to Chang'e-4

Science.gov (United States)

O'Brien, Brian J.

2018-07-01

Strategic purposes of this DAP-2017 report are to update our DAP-2010 report on movements of inescapable fine lunar dust, to summarise key new measurements and to assist rigorous focus. Lunar dust is defined here in two sciences, Apollo dust and Ejecta dust, to end several confusions. The Kuhn Cycle is introduced to stimulate progression of a science about movements of Apollo dust which lacks an agreed paradigm to supply puzzles for scientists to solve and tools for their solution. We populate the cycle with two paradigm shifts. The first was serendipitous invention in 1966 of the Apollo Dust Detector Experiment (DDE), 3 orthogonal solar cells each with a thermometer, which on Apollo 12 measured cause and effect, collective movements of billions to trillions of low-energy Apollo dust particles and changes in temperature they cause. In contrast, Apollo 17 LEAM and LADEE LDEX experiments follow traditions to measure impacts of high-velocity Ejecta dust particles, one by one. In 2015, Apollo 12 DDE discoveries of sunrise-driven storms of Apollo dust stimulated a measurement-based 5-step model of dust transport at astronaut waist height. The discoveries solve (i) 50-year-old mysteries of Horizon Glow, (ii) 30-year-old uncertainties about levitated dust, (iii) processes leading to lunar surfaces being smooth and (iv) immobilisation of the Chang'e-3 lunar rover Yutu in 2014 after its first sunrise. The IAC-2017 Website Abstract of a withdrawn Chang'e-3 presentation may support our views that sunrise-mobilised dust caused immobilisation of Yutu. A precursor to a second paradigm shift was May 2016 announced revision of Chang'e-4 scientific priorities. Using Kuhn terminology of scientific progress, a second shift would follow our "revolution" in 2015 that sunrise-driven dust storms caused the 2014 ″crisis" of immobilisation of Chang'e-3 lunar rover Yutu. No such sequence occurred previously with lunar dust. Measurement-based evidence from Apollo 11 to Chang'e-3 confirms

Field Measurements and Modeling of Dust Transport and Deposition on a Hawaiian Volcano

Science.gov (United States)

Douglas, M.; Stock, J. D.; Cerovski-Darriau, C.; Bishaw, K.; Bedford, D.

2017-12-01

The western slopes of Hawaii's Mauna Kea volcano are mantled by fine-grained soils that record volcanic airfall and eolian deposition. Where exposed, strong winds transport this sediment across west Hawaii, affecting tourism and local communities by decreasing air and water quality. Operations on US Army's Ke'amuku Maneuver Area (KMA) have the potential to increase dust flux from these deposits. To understand regional dust transport and composition, the USGS established 18 ground monitoring sites and sampling locations surrounding KMA. For over three years, each station measured vertical and horizontal dust flux while co-located anemometers measured wind speed and direction. We use these datasets to develop a model for dust supply and transport to assess whether KMA is a net dust sink or source. We find that horizontal dust flux rates are most highly correlated with entrainment threshold wind speeds of 8 m/s. Using a dust model that partitions measured horizontal dust flux into inward- and outward-directed components, we predict that KMA is currently a net dust sink. Geochemical analysis of dust samples illustrates that organics and pedogenic carbonate make up to 70% of their mass. Measured vertical dust deposition rates of 0.005 mm/m2/yr are similar to deposition rates of 0.004 mm/m2/yr predicted from the divergence of dust across KMA's boundary. These rates are low compared to pre-historic rates of 0.2-0.3 mm/yr estimated from radiocarbon dating of buried soils. Therefore, KMA's soils record persistent deposition both over past millennia and at present at rates that imply infrequent, large dust storms. Such events led to soil-mantled topography in an otherwise rocky Pleistocene volcanic landscape. A substantial portion of fine-grained soils in other leeward Hawaiian Island landscapes may have formed from similar eolian deposition, and not direct weathering of parent rock.

Young Asian Dutch constructing Asianness: Understanding the role of Asian popular culture

OpenAIRE

Kartosen, R.A.

2016-01-01

This doctoral thesis is about young Asian Dutch, panethnic Asian identities and identifications, and Asian/Asian Dutch popular culture. It addresses several pressing questions, including: why do young Asian Dutch, who were born and/or raised in the Netherlands, identify as Asian and construct Asian identities? What is the content or meaning of these Asian identities and identifications young Asian Dutch imagine? And how do these relate to young Asian Dutch’ Dutch and homeland identities and i...

Modelling soil dust aerosol in the Bodélé depression during the BoDEx campaign

Science.gov (United States)

Tegen, I.; Heinold, B.; Todd, M.; Helmert, J.; Washington, R.; Dubovik, O.

2006-09-01

We present regional model simulations of the dust emission events during the Bodélé Dust Experiment (BoDEx) that was carried out in February and March 2005 in Chad. A box model version of the dust emission model is used to test different input parameters for the emission model, and to compare the dust emissions computed with observed wind speeds to those calculated with wind speeds from the regional model simulation. While field observations indicate that dust production occurs via self-abrasion of saltating diatomite flakes in the Bodélé, the emission model based on the assumption of dust production by saltation and using observed surface wind speeds as input parameters reproduces observed dust optical thicknesses well. Although the peak wind speeds in the regional model underestimate the highest wind speeds occurring on 10-12 March 2005, the spatio-temporal evolution of the dust cloud can be reasonably well reproduced by this model. Dust aerosol interacts with solar and thermal radiation in the regional model; it is responsible for a decrease in maximum daytime temperatures by about 5 K at the beginning the dust storm on 10 March 2005. This direct radiative effect of dust aerosol accounts for about half of the measured temperature decrease compared to conditions on 8 March. Results from a global dust model suggest that the dust from the Bodélé is an important contributor to dust crossing the African Savannah region towards the Gulf of Guinea and the equatorial Atlantic, where it can contribute up to 40% to the dust optical thickness.

Young Asian Dutch constructing Asianness: Understanding the role of Asian popular culture

NARCIS (Netherlands)

Kartosen, R.A.

2016-01-01

This doctoral thesis is about young Asian Dutch, panethnic Asian identities and identifications, and Asian/Asian Dutch popular culture. It addresses several pressing questions, including: why do young Asian Dutch, who were born and/or raised in the Netherlands, identify as Asian and construct Asian

Original deep convection in the atmosphere of Mars driven by the radiative impact of dust and water-ice particles

Science.gov (United States)

Spiga, A.; Madeleine, J. B.; Hinson, D.; Millour, E.; Forget, F.; Navarro, T.; Määttänen, A.; Montmessin, F.

2017-09-01

We unveil two examples of deep convection on Mars - in dust storms and water-ice clouds - to demonstrate that the radiative effect of aerosols and clouds can lead to powerful convective motions just as much as the release of latent heat in moist convection

DREAMS: a payload on-board the ExoMars EDM Schiaparelli for the characterization of Martian environment during the statistical dust storm season

Science.gov (United States)

Molfese, Cesare; Esposito, Francesca; Debei, Stefano; Bettanini, Carlo; Arruego Rodríguez, Ignacio; Colombatti, Giacomo; Harri, Ari-Matty.; Montmessin, Franck; Wilson, Colin; Aboudan, Alessio; Mugnuolo, Raffaele; Pirrotta, Simone; Marchetti, Ernesto; Witasse, Olivier

2015-04-01

, the dust opacity, and the atmospheric electric properties close to the surface of Mars. It will fly in January 2016 on-board the Schiaparelli Entry, Descent and landing Demonstrator Module (EDM) of the ExoMars space mission. It is foreseen to land on Mars in late October 2016 during the statistical dust storm season. Therefore, DREAMS might have the unique chance to make scientific measurements to characterize the Martian environment in a dusty scenario also performing the first ever measurements of atmospheric electric field on Mars. The relationship between the process of dust entrainment in the atmosphere during dust events and the enhancement of atmospheric electric field has been widely studied in an intense field test campaign in the Sahara desert. In order to better characterize this physical process, we performed atmospheric and environmental measurements comparable to those that DREAMS will acquire on Mars. Preliminary results will be discussed. DREAMS is in a high development state. A first model has been delivered to ESA and has been integrated in the EDM Flight Model. Integration tests are on-going. The DREAMS Flight Model will be delivered at the end of March this year.

Particle size traces modern Saharan dust transport and deposition across the equatorial North Atlantic

Directory of Open Access Journals (Sweden)

M. van der Does

2016-11-01

Full Text Available Mineral dust has a large impact on regional and global climate, depending on its particle size. Especially in the Atlantic Ocean downwind of the Sahara, the largest dust source on earth, the effects can be substantial but are poorly understood. This study focuses on seasonal and spatial variations in particle size of Saharan dust deposition across the Atlantic Ocean, using an array of submarine sediment traps moored along a transect at 12° N. We show that the particle size decreases downwind with increased distance from the Saharan source, due to higher gravitational settling velocities of coarse particles in the atmosphere. Modal grain sizes vary between 4 and 32 µm throughout the different seasons and at five locations along the transect. This is much coarser than previously suggested and incorporated into climate models. In addition, seasonal changes are prominent, with coarser dust in summer and finer dust in winter and spring. Such seasonal changes are caused by transport at higher altitudes and at greater wind velocities during summer than in winter. Also, the latitudinal migration of the dust cloud, associated with the Intertropical Convergence Zone, causes seasonal differences in deposition as the summer dust cloud is located more to the north and more directly above the sampled transect. Furthermore, increased precipitation and more frequent dust storms in summer coincide with coarser dust deposition. Our findings contribute to understanding Saharan dust transport and deposition relevant for the interpretation of sedimentary records for climate reconstructions, as well as for global and regional models for improved prediction of future climate.

Dust Rains Deliver Diverse Assemblages of Microorganisms to the Eastern Mediterranean

Science.gov (United States)

Itani, Ghida Nouhad; Smith, Colin Andrew

2016-03-01

Dust rains may be particularly effective at delivering microorganisms, yet their biodiversities have been seldom examined. During 2011 and 2012 in Beirut, Lebanon, 16 of 21 collected rainfalls appeared dusty. Trajectory modelling of air mass origins was consistent with North African sources and at least one Southwest Asian source. As much as ~4 g particulate matter, ~20 μg DNA, and 50 million colony forming units were found deposited per square meter during rainfalls each lasting less than one day. Sequencing of 93 bacteria and 25 fungi cultured from rain samples revealed diverse bacterial phyla, both Gram positive and negative, and Ascomycota fungi. Denaturing Gradient Gel Electrophoresis of amplified 16S rDNA of 13 rains revealed distinct and diverse assemblages of bacteria. Dust rain 16S libraries yielded 131 sequences matching, in decreasing order of abundance, Betaproteobacteria, Alphaproteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, Cyanobacteria, Epsilonproteobacteria, Gammaproteobacteria, and Deltaproteobacteria. Clean rain 16S libraries yielded 33 sequences matching only Betaproteobacteria family Oxalobacteraceae. Microbial composition varied between dust rains, and more diverse and different microbes were found in dust rains than clean rains. These results show that dust rains deliver diverse communities of microorganisms that may be complex products of revived desert soil species and fertilized cloud species.

Open questions on optical properties of dust and the opacity of the Martian atmosphere

Science.gov (United States)

Korablev, O.; Moroz, V.; Petrova, E.; Rodin, A.

Particulate component of the atmosphere composed by micron-sized products of soil weathering and water ice clouds that strongly affect the current climate of the planet. In the absence of a dust storm so-called permanent dust haze with0.2 in the atmosphere of Mars determines its thermal structure. Dust loading varies substantially with the season and geographic location, and only the data of mapping instruments are adequate to characterize it, such as TES/MGS and IRTM/Viking. In spite of vast domain of collected data, no model is now capable to explain all observed spectral features of dust aerosol. Several mineralogical and microphysical models of the atmospheric dust have been proposed but they cannot explain the pronounced systematic differences between the IR data and measurem ents from the surface (Viking landers, Pathfinder) which give in the quiet seasons the typical optical depth of? 0.5 from one side, and ground-based observations in the UV-visible range that frequently infer <0.2, on the other side. Also the relationship between9 and the visible optical depth is not well established experimentally so far. Future focused measurements are therefore necessary to study Martian aerosol.

Dust Storms: Why Are Dust Storms a Concern?

Science.gov (United States)

... Skip to main content ENVIRONMENTAL HEALTH CONCERNS AND TOXIC CHEMICALS WHERE YOU LIVE, WORK, AND PLAY Search:  Home ... Tree Farm and Logging Uranium Tailings Urban and Industrial Runoff Urban ... Acetone Ammonia Arsenic Asbestos Benzene Bisphenol A (BPA) ...

Viking Lander image analysis of Martian atmospheric dust

Science.gov (United States)

Pollack, James B.; Ockert-Bell, Maureen E.; Shepard, Michael K.

1995-01-01

We have reanalyzed three sets of Viking Lander 1 and 2 (VL1 and VL2) images of the Martian atmosphere to better evaluate the radiative properties of the atmospheric dust particles. The properties of interest are the first two moments of the size distribution, the single-scattering albedo, the dust single-scattering phase function, and the imaginary index of refraction. These properties provide a good definition of the influence that the atmospheric dust has on heating of the atmosphere. Our analysis represents a significant improvement over past analyses (Pollack et al. 1977,1979) by deriving more accurate brightnesses closer to the sun, by carrying out more precise analyses of the data to acquire the quantities of interest, and by using a better representation of scattering by nonspherical particles. The improvements allow us to better define the diffraction peak and hence the size distribution of the particles. For a lognormal particle size distribution, the first two moments of the size distribution, weighted by the geometric cross section, are found. The geometric cross-section weighted mean radius (r(sub eff)) is found to be 1.85 +/- 0.3 microns at VL2 during northern summer when dust loading was low and 1.52 +/- 0.3 microns at VL1 during the first dust storm. In both cases the best cross-section weighted mean variance (nu(eff)) of the size distribution is equal to 0.5 +/- 0.2 microns. The changes in size distribution, and thus radiative properties, do not represent a substantial change in solar energy deposition in the atmosphere over the Pollack et al. (1977,1979) estimates.

Learning Storm

CERN Document Server

Jain, Ankit

2014-01-01

If you are a Java developer who wants to enter into the world of real-time stream processing applications using Apache Storm, then this book is for you. No previous experience in Storm is required as this book starts from the basics. After finishing this book, you will be able to develop not-so-complex Storm applications.

Modelling soil dust aerosol in the Bodélé depression during the BoDEx campaign

Directory of Open Access Journals (Sweden)

I. Tegen

2006-01-01

Full Text Available We present regional model simulations of the dust emission events during the Bodélé Dust Experiment (BoDEx that was carried out in February and March 2005 in Chad. A box model version of the dust emission model is used to test different input parameters for the emission model, and to compare the dust emissions computed with observed wind speeds to those calculated with wind speeds from the regional model simulation. While field observations indicate that dust production occurs via self-abrasion of saltating diatomite flakes in the Bodélé, the emission model based on the assumption of dust production by saltation and using observed surface wind speeds as input parameters reproduces observed dust optical thicknesses well. Although the peak wind speeds in the regional model underestimate the highest wind speeds occurring on 10–12 March 2005, the spatio-temporal evolution of the dust cloud can be reasonably well reproduced by this model. Dust aerosol interacts with solar and thermal radiation in the regional model; it is responsible for a decrease in maximum daytime temperatures by about 5 K at the beginning the dust storm on 10 March 2005. This direct radiative effect of dust aerosol accounts for about half of the measured temperature decrease compared to conditions on 8 March. Results from a global dust model suggest that the dust from the Bodélé is an important contributor to dust crossing the African Savannah region towards the Gulf of Guinea and the equatorial Atlantic, where it can contribute up to 40% to the dust optical thickness.

Current understanding of magnetic storms: Storm-substorm relationships

International Nuclear Information System (INIS)

Kamide, Y.; Gonzalez, W.D.; Baumjohann, W.; Daglis, I.A.; Grande, M.; Joselyn, J.A.; Singer, H.J.; McPherron, R.L.; Phillips, J.L.; Reeves, E.G.; Rostoker, G.; Sharma, A.S.; Tsurutani, B.T.

1998-01-01

This paper attempts to summarize the current understanding of the storm/substorm relationship by clearing up a considerable amount of controversy and by addressing the question of how solar wind energy is deposited into and is dissipated in the constituent elements that are critical to magnetospheric and ionospheric processes during magnetic storms. (1) Four mechanisms are identified and discussed as the primary causes of enhanced electric fields in the interplanetary medium responsible for geomagnetic storms. It is pointed out that in reality, these four mechanisms, which are not mutually exclusive, but interdependent, interact differently from event to event. Interplanetary coronal mass ejections (ICMEs) and corotating interaction regions (CIRs) are found to be the primary phenomena responsible for the main phase of geomagnetic storms. The other two mechanisms, i.e., HILDCAA (high-intensity, long-duration, continuous auroral electrojet activity) and the so-called Russell-McPherron effect, work to make the ICME and CIR phenomena more geoeffective. The solar cycle dependence of the various sources in creating magnetic storms has yet to be quantitatively understood. (2) A serious controversy exists as to whether the successive occurrence of intense substorms plays a direct role in the energization of ring current particles or whether the enhanced electric field associated with southward IMF enhances the effect of substorm expansions. While most of the Dst variance during magnetic storms can be solely reproduced by changes in the large-scale electric field in the solar wind and the residuals are uncorrelated with substorms, recent satellite observations of the ring current constituents during the main phase of magnetic storms show the importance of ionospheric ions. This implies that ionospheric ions, which are associated with the frequent occurrence of intense substorms, are accelerated upward along magnetic field lines, contributing to the energy density of the

Recent trends of plutonium deposition observed in Japan: comparison with naturallithogenic radionuclides, thorium isotopes

International Nuclear Information System (INIS)

Hirose, K.; Igarashi, Y.; Aoyama, M.

2005-01-01

Plutonium in monthly deposition samples from 2000 to end of 2003 collected to Tsukuba (the Meteorological Research Institute), Japan is reported, together with monthly thorium deposition. The annual deposition of 239,240 Pri during the past 18 years. ranged from 1.7 to 7.8 mBq m -2 y -1 shows no systematic inter-annual variation. However, a maximum annual 239,240 Pu deposition (7.8 mBq m -2 y -1 ) was observed in 2002. On the other hand, monthly 239,240 Pu depositions show a typical seasonal variation with a maximum in spring season (March to April), which corresponds to the seasonal cycle of generation of dust storms in the East Asian arid area. Thorium, which is a typical lithogenic radionuclide, reflects soil-derived particles in the atmospheric dust. The monthly Th deposition showed a typical seasonal trend with a maximum in spring and minimum in summer. The 230 Th/ 232 Th activity ratios in the deposition samples significantly differed from that in surface soils collected in Tsukuba area, which means that a significant part of thorium in deposition samples is not derived from suspension of local soil particles. The result reveals that the resent 239,240 Pu deposition observed in Japan are attributed to resuspension of deposited plutonium; resuspended plutonium originates from the East Asian continent desert and arid areas. These findings suggest that a significant amount of soil dust observed in Tsukuba is attributable to the long-range transport of continental dust from the East Asian arid areas. Plutonium in deposition samples as does thorium would become a proxy of the environmental change in the Asian continent.

Combined TOPEX/Poseidon TEC and ionosonde observations of negative low-latitude ionospheric storms

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K. J. W. Lynn

2004-09-01

Full Text Available Ionospheric storms showing a strong depression in daytime foF2 values were sought which penetrated to low-latitudes, as identified by vertical ionosondes operating at Darwin and Townsville over the period 1992-1998. The 32 storms thus identified showed a seasonal occurrence peaking near the equinoxes with a bias to the summer side. Of these storms, three (27 March 1995, 25 October 1997, 8 November 1997 combined Australian and South East Asian ionosonde observations with local afternoon TOPEX/Poseidon measurements of TEC. The equatorial anomaly is usually well developed at this time of day and consequently these storms were chosen for detailed study. The TOPEX/Poseidon satellite provided vertical profiles of the ionosphere across both hemispheres, thus allowing the totality of storm behaviour to be observed for the first time at low-latitudes and related directly to the ionosonde observations. The three storms were remarkably consistent in their behaviour, the negative ionospheric storm day followed some 24-36h after the beginning of a magnetic storm and the development of the equatorial anomaly was suppressed. However, the suppression of the equatorial anomaly was not the main cause of the strong depression in foF2 observed by the Southern Hemisphere ionosondes. The latter was associated with an additional bite-out in both TEC and foF2 that occurred on the southern side of the magnetic equator. None of the three storms produced any major negative disturbance outside the range of normal variability of TEC and foF2 at the northern latitude sites for which data was available, despite the absence of the anomaly. The satellite measurements show the strength of the anomaly to be highly variable from day-to-day and anomaly peaks are frequently not present even on magnetically quiet days. Thus, an absence of anomaly peaks is contained within the normal variability of non-storm days. The north-south asymmetry and seasonal occurrence are consistent with

Coastal Storm Surge Analysis: Storm Forcing. Report 3. Intermediate Submission No. 1.3

Science.gov (United States)

2013-07-01

The storm surge study considers both tropical storms and extratropical cyclones for determination of return period storm surge elevations. The...Appendix B: Extratropical Cyclone Selection in Support of FEMA Region III Storm Surge Modeling...stations applied in the storm selection process. ............................................. 56  Table B2. Extratropical cyclones selected from the

Mechanisms of Saharan Dust Radiative Effects Coupled to Eddy Energy and Wave Activity

Science.gov (United States)

Hosseinpour, F.; Wilcox, E. M.; Colarco, P. R.

2017-12-01

We explore mechanisms addressing the relationships between the net radiative forcing of Saharan Air Layer (SAL) and eddy energetics of the African Easterly jet-African easterly wave (AEJ-AEWs) system across the tropical Atlantic storm track. This study indicates that radiatively interactive dust aerosols have the capability to modify the exchange of kinetic energy between the AEWs and AEJ. We find that while dust can have both constructive and destructive effects on eddy activity of the waves, depending on the behavior and structure of waves exhibiting different characteristic time-scales, the local heating by dust tends to change the quadruple pattern of eddy momentum fluxes of the AEWs which can yield feedbacks onto the mean-flow. These results arise from applying an ensemble of large NASA satellite observational data sets, such as MODIS, SeaWiFS and TRMM, as well as the GOCART aerosol model and MERRA reanalysis. Sensitivity studies indicate that the results are consistent when the analysis is performed with multiple different aerosol datasets. While the mechanisms proposed here require further evaluation with numerical model experiments, this study presents a novel approach and new insights into Saharan dust effects on large-scale climate dynamics.

Diurnal cycle of the dust instantaneous direct radiative forcing over the Arabian Peninsula

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