Dust Salt Research Articles

Aerosol Optical Properties over the Ebinur Region

The key to understanding the transport and deposition process of salt dust to Ebinur Lake involves the quantitative evaluation of the aerosol concentration and characteristics in Jinghe County. Based on the data of the CE-318 sun photometer station in Jinghe County during 2019, the characteristics of the aerosol optical depth (AOD) and Angström exponent (α) were analysed. The results showed that the daily variation of the AOD in Jinghe County was a single peak curve that increased or decreased monotonously in the early/late peak period and peaked at 12:00-14:00, which was opposite to the trend of the α. There were obvious seasonal differences in the aerosol concentration and dominant mode. The seasonal AOD was ranked as:spring (0.403±0.282) > summer (0.222±0.135) > autumn (0.218±0.112), whereas α was ranked as:summer (1.339±0.446) > autumn (1.116±0.278) > spring (0.914±0.269). During the spring, the range of the change in the AOD was more intense, the aerosol particle size was larger than that during the summer and autumn, and the range of the variation in the particle size was larger. There was a negative correlation between the AOD and α. During the spring and summer, the aerosol particle size varied over a wide range, and the composition was more complex. With the decrease of the α, the AOD tended to increase; during the autumn, the dominant aerosol mode (mainly fine particles) stabilized, and the AOD exhibited no obvious change with the α. From spring to autumn, aerosol gradually transited from a coarse to fine mode. Compared with the summer, local aerosols were more sensitive to the changes of the wind speed, wind direction, and relative humidity during the spring. The primary reason for the increase of the AOD during the spring was the main wind direction and the dust input brought by gale weather. Influenced by the soluble salt ions in the dust, the aerosol particles were able to undergo hygroscopic growth, but this was not the main reason for the high AOD. Temperature was not the internal factor for the change in the local aerosols; however, it was directly proportional to the diffusion ability of aerosol particles. Overall, the AOD of Jinghe County was primarily affected by dust aerosols. The increases in the amounts of small particles and aerosol moisture absorption were not the main reasons for the increase of the AOD in this area.

Optical properties of Central Asian aerosol relevant for spaceborne lidar applications and aerosol typing at 355 and 532 nm

Abstract. For the first time, a dense data set of particle extinction-to-backscatter ratios (lidar ratios), linear depolarization ratios, and backscatter- and extinction-related Ångström exponents for a Central Asian site are presented. The observations were performed with a continuously running multiwavelength polarization Raman lidar at Dushanbe, Tajikistan, during an 18-month campaign (March 2015 to August 2016). The presented seasonally resolved observations fill an important gap in the database of aerosol optical properties used in aerosol typing efforts with spaceborne lidars and ground-based lidar networks. Lidar ratios and depolarization ratios are also basic input parameters in spaceborne lidar data analyses and in efforts to harmonize long-term observations with different space lidar systems operated at either 355 or 532 nm. As a general result, the found optical properties reflect the large range of occurring aerosol mixtures consisting of long-range-transported dust (from the Middle East and the Sahara), regional desert, soil, and salt dust, and anthropogenic pollution. The full range from highly polluted to pure dust situations could be observed. Typical dust depolarization ratios of 0.23–0.29 (355 nm) and 0.30–0.35 (532 nm) were observed. In contrast, comparably low lidar ratios were found. Dust lidar ratios at 532 nm accumulated around 35–40 sr and were even lower for regional background dust conditions (20–30 sr). Detailed correlation studies (e.g., lidar ratio vs. depolarization ratios, Ångström exponent vs. lidar ratio and vs. depolarization ratio) are presented to illuminate the complex relationships between the observed optical properties and to identify the contributions of anthropogenic haze, dust, and background aerosol to the overall aerosol mixtures found within the 18-month campaign. The observation of 532 nm lidar ratios (<25 sr) and depolarization ratios (around 15 %–20 %) in layers with very low particle extinction coefficient (<30 sr) suggests that direct emission and emission of resuspended salt dust (initially originated from numerous desiccating lakes and the Aralkum desert) have a sensitive impact on the aerosol background optical properties over Dushanbe.

Exploring the spatial-temporal characteristics of the aerosol optical depth (AOD) in Central Asia based on the moderate resolution imaging spectroradiometer (MODIS).

Central Asia has become a key node of the belt and road corridor. It is located in arid and semi-arid climate regions, and it is a region where the contribution of global aerosols of sand and dust is continuous. However, few studies have been conducted on the Central Asian aerosol optical depth. Therefore, this paper relied on the belt and road sustainable development dataset to analyze the spatial-temporal variations in the AOD in Central Asia and provide spatial-temporal characteristics of the AOD for environmental services. We analyzed the spatial and temporal variation in the aerosol optical depth (AOD) in Central Asia by using MODIS/AQUA C6 MYD08_M3 images from 2008 to 2017. The results showed that (1) the annual average AOD in Central Asia in the past decade varied from 0.183 to 0.232, which indicated a slow decline starting in 2014. The percentage of average annual decline was approximately 0.18%, and the regular distinct revealed the distribution characteristics of AOD. In different years, the Central Asian region exhibited the similar monthly change characteristics: from July to December, the AOD decreased, and from December to February, it increased. In different seasons, the Central Asian region exhibited the different seasonal change characteristics: the AOD value was higher in the spring and summer. The mean values in the spring, summer, autumn, and winter were 0.273, 0.240, 0.155, and 0.183, respectively, and the standard deviations were 0.036, 0.038, 0.025, and 0.048, respectively. (3) Based on spatial distribution characteristics, the Tarim Basin, Aral Sea region, and Ebinur Lake area were high value areas, and Kazakhstan was a low value area. The AOD of the surrounding area of the Aral Sea had increased in the last 5years, while that of Kazakhstan, Uzbekistan, and Turkmenistan had decreased. The AOD of the Taklamakan area exhibited an inter-annual change. Sand dust aerosols were the largest contributors to the AOD in the Taklamakan area. The rising trend of the AOD in the Aral Sea area was clear, with an average annual increase of 0.234%, and the contribution of salt dust aerosols to the AOD increased. The average annual AOD in the Ebinur Lake area remained stable.

Giant Water Clusters: Where Are They From?

A new mechanism for the formation and destruction of giant water clusters (ten to hundreds of micrometers) is proposed. Our earlier hypothesis was that the clusters are associates of liquid-crystal spheres (LCS), each of which is formed around a seed particle, a microcrystal of sodium chloride. In this study, we show that the ingress of LCSs into water from the surrounding air is highly likely. We followed the evolution of giant clusters during the evaporation of water. When a certain threshold of the ionic strength of a solution is exceeded, the LCSs begin to “melt”, passing into free water, and the salt crystals dissolve, ensuring re-growth of larger crystals as a precipitate on the substrate. A schematic diagram of the dynamics of phase transitions in water containing LCSs during evaporation is proposed. The results illustrate the salt dust cycle in nature.

Remote sensing-based land surface change identification and prediction in the Aral Sea bed, Central Asia

The human-induced desiccation of the Aral Sea has generated large amounts of salt dust and has been posing a great threat to local ecological environment and human health. Monitoring its land cover changes is essential to obtaining information about the desertification process and dynamics of potential salt/sand dust source. To this end, long-term Landsat imagery was applied for the land use/cover change analysis based on support vector machine approach. The land cover distribution of the study area for 1977, 1987, 1996, 2006 and 2015 was mapped. In addition, the Markov–cellular automata integrated approach was used to predict the land cover change in 2015 and project changes in 2025 by extrapolating current trends. The classification results revealed that water surface of the Aral Sea shrunk by more than 66%, leading to the dramatic expanding of the salt soil and bare area. Change detection analysis indicated a serious land degradation trend as well as a major land cover evolution mode in the Aral Kum that could predict shifts in dust composition. The Markov–cellular automata technique was successful in predicting land cover distribution in 2015, and the projected land cover for 2025 revealed more desertification of the landscape with potential expansion in the salt soils and bare area. It is worth noting that the vegetation cover of the region represented an obvious increase in recent years that may be a good signal of ecological recovery.

Observational study on salt dust aerosol optical properties using the ground-based and satellite remote sensing

Observational study on salt dust aerosol optical properties using the ground-based and satellite remote sensing

Assessment of Oral Health among Salt Workers of Little Rann of Kutch, North Gujarat

<div><p><em>Exposure to industrial chemicals and ecological pollutants results in sober health hazards amongst the workers and general public. Salt workers are exposed to various environmental conditions like direct sunlight, salt dust and make contact with brine, which encompass an impact on the health of workers. While oral wellbeing is an vital part of the general health, we intended to establish its effect on the oral health.</em></p><p><strong><em>Objectives:</em></strong><em> </em><em>To assess the oral health among the salt workers of Little Rann of Kutch, North Gujarat, India.</em></p><p><strong><em>Material and Methods:</em></strong><em> </em><em>A cross sectional, descriptive survey was conducted among 650 Salt workers of little rann of kutch, subjects, Information was gathered on the demographic profile followed by clinical examination for recording the oral health, based on the WHO guidelines. The Chi–square test, t–test, were used for the statistical analysis.</em></p><p><strong><em>Results: M</em></strong><em>ean DMFT of females (</em><em>6.49 ± 4.15) were significantly higher as compared to those in males (p=0.001). Majority of the study participants had dental fluorosis and Attachment loss of 4–5 mm and 6-8 mm and the mean number of sextants were significantly higher among males than among females (p=0.05) </em></p><p><strong><em>Conclusion:</em></strong><em> significant amount of salt workers have a higher prevalence of oral diseases. Implying a deprived ease of access and accessibility to oral health car</em>e. </p></div>

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

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.

Potential transport pathways of dust emanating from the playa of Ebinur Lake, Xinjiang, in arid northwest China

In this paper, the HYSPLIT model, driven with reanalysis meteorological data from 1978 to 2013, was used to understand the potential transport characteristics of dust and salt dust emanating from the playa of Ebinur Lake in arid northwest China. Daily air parcel trajectories were computed forward for 8days from an origin centered over Ebinur Lake at 100m above ground level. Air parcel trajectory density plots were mapped for seven levels: 0–100m agl., 100–500m agl., 500–1000m agl., 1000–1500m agl., 1500–2000m agl., 2000–3000m agl., and 3000–5000m agl. These show that potential dust transport pathways have clear seasonal differentiation. The potential transport distance of dust and salt dust is greatest in spring and summer. In autumn and winter, the potential transport of the high-density air trajectory is below 1000m traveling a shorter distance. Potential dust transport pathways showed notifying directivity in different seasons and heights. Southeast in spring and summer, and north to northeast in autumn and winter are the two main potential transport channels of dust and salt dust. Accordingly, dust and salt dust from the playa of Ebinur Lake may influence the atmospheric processes and biogeochemical cycles of a vast region. The main area of influence of dust and salt dust is close to the source area, and will significantly accelerate the melting of snow and ice in the Tianshan Mountains. This highlights the urgent need to combine remote sensing, isotope and other methods to further research the transport characteristics of dust and salt dust from the playa of the Ebinur Lake.

The disastrous effects of salt dust deposition on cotton leaf photosynthesis and the cell physiological properties in the Ebinur Basin in Northwest China.

Salt dust in rump lake areas in arid regions has long been considered an extreme stressor for both native plants and crops. In recent years, research on the harmful effects of salt dust on native plants has been published by many scholars, but the effect on crops has been little studied. In this work, in order to determine the impact of salt dust storms on cotton, we simulated salt dust exposure of cotton leaves in Ebinur Basin in Northwest China, and measured the particle sizes and salt ions in the dust, and the photosynthesis, the structure and the cell physiological properties of the cotton leaves. (1) Analysis found that the salt ions and particle sizes in the salt dust used in the experiments were consistent with the natural salt dust and modeled the salt dust deposition on cotton leaves in this region. (2) The main salt cations on the surface and inside the cotton leaves were Na+, Ca2+, Cl- and SO4 2-, while the amounts of CO3 - and HCO3 - were low. From the analysis, we can order the quantity of the salt cations and anions ions present on the surface and inside the cotton leaves as Na+>Ca2+>Mg2+>K+ and Cl->SO4 2->HCO3 ->CO3 -, respectively. Furthermore, the five salt dust treatment groups in terms of the total salt ions on both the surface and inside the cotton leaves were A(500g.m-2)>B(400g.m-2)>C(300g.m-2)>D(200g.m-2)>E(100g.m-2)>F(0g.m-2). (3)The salt dust that landed on the surface of the cotton leaves can significantly influence the photosynthetic traits of Pn, PE, Ci, Ti, Gs, Tr, WUE, Ls, φ, Amax, k and Rady of the cotton leaves. (4)Salt dust can significantly damage the physiological functions of the cotton leaves, resulting in a decrease in leaf chlorophyll and carotenoid content, and increasing cytoplasmic membrane permeability and malondialdehyde (MDA) content by increasing the soluble sugar and proline to adjust for the loss of the cell cytosol. This increases the activity of antioxidant enzymes to eliminate harmful materials, such as the intracellular reactive oxygen and MDA, thus reducing the damage caused by the salt dust and maintaining normal physiological functioning. Overall, this work found that the salt dust deposition was a problem for the crop and the salt dust could significantly influence the physiological and biochemical processes of the cotton leaves. This will eventually damage the leaves and reduce the cotton production, leading to agricultural economic loss. Therefore, attention should be paid to salt dust storms in the Ebinur Basin and efficient measures should be undertaken to protect the environment.

Evaluation of the global aerosol microphysical ModelE2-TOMAS model against satellite and ground-based observations

Abstract. The TwO-Moment Aerosol Sectional (TOMAS) microphysics model has been integrated into the state-of-the-art general circulation model, GISS ModelE2. This paper provides a detailed description of the ModelE2-TOMAS model and evaluates the model against various observations including aerosol precursor gas concentrations, aerosol mass and number concentrations, and aerosol optical depths. Additionally, global budgets in ModelE2-TOMAS are compared with those of other global aerosol models, and the ModelE2-TOMAS model is compared to the default aerosol model in ModelE2, which is a one-moment aerosol (OMA) model (i.e. no aerosol microphysics). Overall, the ModelE2-TOMAS predictions are within the range of other global aerosol model predictions, and the model has a reasonable agreement (mostly within a factor of 2) with observations of sulfur species and other aerosol components as well as aerosol optical depth. However, ModelE2-TOMAS (as well as ModelE2-OMA) cannot capture the observed vertical distribution of sulfur dioxide over the Pacific Ocean, possibly due to overly strong convective transport and overpredicted precipitation. The ModelE2-TOMAS model simulates observed aerosol number concentrations and cloud condensation nuclei concentrations roughly within a factor of 2. Anthropogenic aerosol burdens in ModelE2-OMA differ from ModelE2-TOMAS by a few percent to a factor of 2 regionally, mainly due to differences in aerosol processes including deposition, cloud processing, and emission parameterizations. We observed larger differences for naturally emitted aerosols such as sea salt and mineral dust, as those emission rates are quite different due to different upper size cutoff assumptions.

Salt dust storm in the Ebinur Lake region: its 50-year dynamic changes and response to climate changes and human activities

The dynamic changes characteristics of salt dust storm in the Ebinur Lake of Xinjiang were investigated using the monitoring data during 1957–2007 of atmospheric dust storm and floating dust from four meteorological stations surrounding the dry lakebeds, and the gray correlation analysis method was used to calculate the correlation degree between annual dust storm days and meteorological and socioeconomic factors. The results showed that salt dust storm in the Ebinur Lake region presented a fluctuating process during 1957–2007, in which 1975 and 2000 were the two cut-off points. During 1975–2000, there were very frequent storms, and the average annual number of salt dust storm days was 10–48, while the average annual number of storm days was not more than 12 both before 1975 and after 2000. The annual variation of salt dust storm displayed a double-peak pattern, of which storm in spring accounted for 62–90 % of the total dust storm days of a year, and that in autumn accounted for 7–13 %. Among the meteorological factors, strong winds had the greatest impact on salt dust storm, followed by temperature and precipitation. For the anthropogenic factors, agricultural acreage exhibited the strongest influence on salt dust storm, followed by lake surface area and population number, while livestock number showed the smallest effect.

艾比湖湿地退化对盐尘暴发生及运移路径的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 艾比湖湿地退化对盐尘暴发生及运移路径的影响 DOI: 10.5846/stxb201312263034 作者: 作者单位: 新疆大学资源与环境科学学院 绿洲生态教育部重点实验室 作者简介: 通讯作者: 中图分类号: X87 基金项目: 国家自然科学基金项目(41130531,41261090,41161063) Effect of salt dust storm migration pathways on degradation of Ebinur Lake Wetland Author: Affiliation: College of Resources and Environment Science,Xinjiang University,Key Laboratory of Oasis Ecosystem of Education Ministry,Xinjiang University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:新疆艾比湖湿地内间歇性裸露的干涸湖底加重了周围区域的盐渍化程度,为盐尘暴的发生发展提供了粉尘物质来源。盐碱粉末在风力作用下以颗粒物的形式悬浮在空中并向周围扩散,严重危害周边区域的生态安全和社会经济发展。本文选择研究区三期遥感影像,结合同期野外实测大气降尘及地表土壤采样数据,剖析区域土壤盐渍化与盐尘暴发生作用机制,探讨艾比湖湿地退化引发的盐尘暴在传输、沉降过程中对源地及途经区域的生态环境的影响,进而对盐尘暴的运移路径进行模拟预测。有关成果对于揭示该区域独特的盐尘暴发生及作用机制问题具有重要作用。 Abstract:The lake wetlands are a transition zone between aquatic and terrestrial ecosystems. They are also one of the most important environments that sustain human beings, especially in arid and semi-arid areas of Northwestern China. The lake wetland ecosystem not only serves as an important media reflecting the dynamics of the local natural processes and habitat, but also promotes the interaction between human beings and the nature to maintain a sustainable balance between the two. Salt dust storm and alkaline dust deposition are generally caused by lack of water as loose deposits, dry lake bed crust, salt and saline soil are blown and salt deposits are dispositioned due to wind erosion. The salt powder in the form of suspended particles in the air becomes a natural disaster accompanied with strong wind. In addition to saline, alkaline elements, it contains crystalline dry lakebed sediments, toxic chemicals, and harmful heavy metal particles, which threaten plant survival. The development process of alkaline dust storm not only contaminates the air, food, water, and other natural resources with a mix of bacteria, fungi, and other toxic and harmful substances, but it also destroys the grassland and crops, and causes various diseases in humans and livestock. Intermittently exposed lake bottom of dry lake in the Ebinur Lake region is the primary source for salt dust storms in the surrounding area. Saline powder suspends in the air and spreads in the form of particles with the wind, seriously endangering the ecological stability and socio-economic development of the surrounding area. The current study attempts to investigate the dust storm migration pathways and its environmental effects using three remote sensing images combined with synchronous field measurements of salt dust and surface soil samples with the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model. We also explore the environmental changes caused by salt dust storms and their impacts on the settlement process of Ebinur Lake by simulating and predicting the migration pathways of salt dust storms. Combining atmospheric dust deposition and surface soil data as well as the westerly direction and airflow path, we simulated the transport trajectories of salt dust for about four months in Bortala Mongol Autonomous Prefecture of Xinjiang Uyghur Autonomous Region, China. The results indicate that: (1) the degree of soil salinization within the study area is uneven. The highest level of salinization occurs around the Ebinur Lake but gradually weakens towards the peripheral expansion areas; (2) the dynamics of saline land is closely related to the change in vegetation cover and water area and to human activity, which also has a significant impact on the evolution of soil salinization; (3) there are two different paths of salt dust storm, the north path starting from Bortala Mongol Autonomous Prefecture→Aletai→Gansu→Inner Mongolia→Mongolia→Heilongjiang and southeastern path from Bortala Mongol Autonomous Prefecture (Jinghe, Bole, Wenquan, and Alashankou)→Wusu→Kuitun→Vrümqi→Kurla→Turpan→Kumul. Our results present important information regarding the occurrence and mechanism of salt and dust storms in arid and semi-arid regions. 参考文献 相似文献 引证文献

Cover Picture: Mining Report 4/2014

AbstractEfficient solutions are required in the field of work and environmental safety, which improve the level of safety. In this context dedusting and air cleaning are key challenges even today. Since 1999 the company CFT GmbH Compact Filter Technic is specialized in the development and construction of patented dedusting plants in the field of mining and tunnelling. At present a CFT dry‐type deduster of the type HTKK 1/750‐2S is in use in the Polish rock salt mine Polkowice Sieroszowice of the Polish mining company KGHM Polska Miedź S.A. With a suction output of 1,050 m3/min it filters approximately 2 tons of salt dust per hour out of the air. The filter elements are cleaned fully automated and the collected dust is automatically discharged.

English

The helicopters used for marine operations encounter harsh environment laden with salt mist, sand and dust which could accelerate the deterioration of components. Assessment of the effect of operational environment on component degradation of such helicopter engines is crucial in scheduling their maintenance and ensuring flight safety. The objective of this study is to understand and assess the differential degradation pattern of aeroengines operated in marine environment in comparison to their counterparts operated in non-marine environment. In this study, a sample of 257 ex-service aeroengines of same type and make, operated in marine and non-marine environment were randomly selected and their degradation pattern observed. After obtaining the data on component degradation, further statistical analysis was carried out and the statistical significance of the observations were computed. Out of the ten major components considered in this study, five of them were found to have statistically significant differential degradation due to operation in marine environment. For the remaining components adequate evidence was not available to substantiate differential degradation due to operation in marine environment. These findings serve as valuable input for maintenance inventory planning as well as component improvement programme. Defence Science Journal, Vol. 64, No. 4, July 2014, pp. 371-377, DOI:http://dx.doi.org/10.14429/dsj.64.4007

The Oral Health Status and the Treatment Needs of Salt Workers at Sambhar Lake, Jaipur, India

Salt workers are exposed to the adversities of environmental conditions such as direct sunlight, salt dust and contact with brine, which have an impact on the health of workers. Since oral health is an integral part of the general health, we planned to determine its effect on the oral cavity. To assess the oral health status and the treatment needs among the workers of Sambhar Salts Limited at Sambhar Lake, Jaipur, India. A cross sectional, descriptive survey was conducted among 979 subjects (509 males; 470 females) who were aged between 19-68 years, who were the workers of Sambhar Salts Limited, Sambhar Lake, Jaipur, India. An interview on the demographic profile followed a clinical examination for recording the oral health status, based on the World Health Organization guidelines. The Chi-square test, t-test, One way Analysis of Variance and a Stepwise multiple linear regression analysis were used for the statistical analysis. Females had a significantly greater prevalence of dental fluorosis (71.7%) and periodontal disease (96.4%) as compared to males (p= 0.001). The mean number of healthy sextants (0.71 ± 0.09) and the mean DMFT (5.19 ± 4.11) were also significantly higher in females as compared to those in males (p=0.001). One surface filling (78.2%), followed by pulp care and restoration (76.1%) were the most prevalent treatment needs. The gender and oral hygiene practices for dental caries and periodontal disease were respectively identified as the best predictors. Considerable percentages of salt workers have demonstrated a higher prevalence of oral diseases. Higher unmet treatment needs suggest a poor accessibility and availability of oral health care, in addition to a low utilization of preventive or therapeutic oral health services.

Quantification of salt dust pathways from a groundwater‐fed lake: Implications for solute budgets and dust emission rates

Emissions of salt dust from the shores of saline lakes significantly impact lake chemistry, air quality, transportation, human health, and climate. Quantitative methods for assessing these emissions, however, are still in the developmental stage. We investigate salt pathways from groundwater to dust using an approach that takes advantage of opportune conditions at a groundwater‐fed, saline lake in the Nebraska Sand Hills region. The mass of salt in the lakeshore surface crust and soil was measured, as well as in the dust on the surrounding dune field. These data, together with information on the lake hydrology, show that dust emission is an important mechanism controlling lake salinity, even though a mere fraction of the salt crust is deflated each year under extant climatic conditions. Wind data collected at the lake site indicate high wind speeds capable of dust mobilization. Therefore, the physical and chemical bonding of salts in the crust is offered as the primary limiting factor for dust emission rates.

A GAME THEORY APPROACH TO SALINIZATION PROBLEM OF THE ARAL SEA BASIN

This paper studies a transboundary economy with two countries located in a lake basin. Each country withdraws water from the lake for irrigation purposes, which in turn causes the lake to desiccate. The receding lake leaves surfaces covered with salt dust, which is transported by wind to the surrounding area, increasing the salinity of the two countries' lands. This paper examines whether a partially cooperative water - allocation scheme, where a central authority chooses the two countries' respective abatement levels (of salt dust) after the countries individually choose per-unit taxes on water withdrawal, induces the countries to withdraw water at the socially efficient level. We find that the partial scheme works, i.e. it induces both countries to optimally choose to withdraw at the socially efficient level.

Nubes de polvo salino y humo en la laguna de Mar Chiquita, provincia de Córdoba, Argentina, agosto de 2009

Nubes de polvo salino y humo en la laguna de Mar Chiquita, provincia de Córdoba, Argentina, agosto de 2009

How present aerosol pollution from North America impacts North Atlantic climate

This paper describes the potential effects of present-day aerosol pollution from North America (USA, Canada) on the climate of the North Atlantic region. The study has been performed by applying the comprehensive atmospheric general circulation model ECHAM5-HAM, which is coupled to a mixed-layer ocean with an embedded thermodynamic sea ice module. The model includes a microphysical aerosol model (HAM), which allows for the assessment of aerosol impacts on climate. Sulphate, black and organic carbon, sea salt and mineral dust are considered as aerosol species. Two equilibrium simulations with two different aerosol pollutant scenarios are compared for each season.We investigate the effect on radiation, temperature, hydrological quantities and dynamics, when human-induced aerosol emissions from North America were omitted. The decrease of both direct and indirect aerosol effects induces a positive change in top of the atmosphere (TOA) radiative fluxes resulting in an overall warming in the whole region. Our results demonstrate the vulnerability especially of the Arctic to the reduction in aerosol load. For fall we find an increase in precipitation over the North Atlantic, associated with a tendency to a larger number of cyclones with high-pressure gradients and a higher frequency in storm days.