Search

Abstract: Polarization-sensitive Mie-scattering lidars were installed for dust storm monitoring at Sainshand and Zamyn-Uud in the Gobi Desert and at the Mongolian capital city of Ulaanbaatar in 2007. We studied the temporal and spatial distributions and transportation of dust, elevated dust, biomass burning smoke, and anthropogenic aerosol by using lidar measurements from the end of 2007 to the first half of 2010. The study results show that the maximum height of dust layers over the Gobi Desert of Mongolia during dust event periods varied from 0.5 to 5.5 km above the ground level (AGL). The 95th percentile level of dust vertical distribution was found at 4 and 4.5 km for Zamyn-Uud and Sainshand, respectively. The averaged maximum height of dust layers during dust events was 2.0–2.2 km AGL at those Gobi sites. The lidar measurements also revealed transport of dust layers elevated in the atmosphere. Base heights of elevated dust layers varied from 0.5 to 2.5 km AGL, while maximum heights from 2.5 to 4.5 km AGL. Backward air trajectory analyses suggested source areas of the elevated dust that transported from other source regions to southeastern Mongolia. A detail study was conducted of the dust event in 19–20 May 2008. Hourly maximum dust concentrations of PM10 (PM2.5) reached 1139–1409 (384–404) μg m−3 during the dust event episode. Dust concentration of PM10 had high correlations with visibilities. Threshold winds for dust emission were determined at Sainshand and Zamyn-Uud. The lidar measurements at the three sites detected vertical profiles of biomass burning smoke and anthropogenic aerosol with top heights of 3–4 km AGL. [Copyright &y& Elsevier]

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/90 Sr 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 precipitation. These findings suggest that the increased specific activities and the activity ratio detected in atmospheric depositions in Japan during years with frequent Asian dust transport events in the 2000s are a sign of grassland degradation. [ABSTRACT FROM AUTHOR]

Abstract: Dust mass concentrations of PM10 and PM2.5 from four monitoring stations in the Gobi Desert region of Mongolia were analyzed for a 16-month period in 2009–2010. Annual averaged PM10 concentration ranged from 9μgm−3 to 49μgm−3 at these stations during 2009. Concentrations were high in winter owing to air pollution and in spring owing to dust storms; the monthly mean concentrations of PM10 (PM2.5) at the three stations except for Sainshand reached yearly maxima in December and January, ranging from 60 (38) μgm−3 to 120 (94) μgm−3. Diurnal variations of PM10 and PM2.5 concentrations at two sites, Dalanzadgad and Zamyn-Uud, included two maxima in the morning and evening and two minima in the afternoon and early morning. However, at Erdene PM10 maxima occurred in the afternoon and evening. Both PM10 and PM2.5 concentrations were enhanced from March to May by dust storms. Dust storms raised huge amounts of fine dust particles in the Gobi of Mongolia. Maximum daily mean PM10 (PM2.5) concentrations reached 821 (500) μgm−3 at Dalanzadgad, 308 (129) μgm−3 at Zamyn-Uud, and 1328μgm−3 at Erdene. Hourly maximum PM10 (PM2.5) concentrations were as high as 6626 (2899) μgm−3 at Dalanzadgad during a dust storm. [Copyright &y& Elsevier]

Dust storms frequently occur in Mongolia and in northern China. Each year there are 30 to 120 dusty days in source regions of Mongolia and 14–20 dusty days on the Korean Peninsula. Intense sand storms and associated dust falls produce environmental impacts in East Asia. This paper discusses the environmental degradation in Mongolia and the social, economic and atmospheric impacts of dust storms in the sink area. The impact of dust storms on environmental compartments as well as their direct and indirect consequences to basic resources like water and energy demand and supply is explained. Governments are encouraged to take appropriate action in specified regions. For monitoring dust storms there is a need for international cooperation to combat growing environmental and human security concerns. [ABSTRACT FROM AUTHOR]

A joint monitoring of dust-storms that occurred in East Asia from March until May 2003 has been carried. Our discussions include dust-storm observations in the source areas of China and Mongolia, and measurements with satellites and ground monitors in central Korea. Differences were found in the definition and measurement of dust-storms. Over the source area of Mongolia there were 6 dusty days in March, 18 days in April, and 10 dusty days in May. In Inner Mongolia of northern China there were 4 dust-storms with 14 dusty days observed over the three months. In central Korea, a sink area, there were 4 cases of weak dust-storm and 17 dusty days in the spring of 2003. The highest PM10 value was 607 μgm−3 and PM 2.3 was 149 μgm−3, respectively. These observations identify the growing need for further universal observation practices and dust-storm reporting in future. Observations indicated that snow covered the central part of the Gobi Desert, near the boundary of China and Mongolia, from December until mid-March. This is in contrast to other years when the Gobi was relatively wet, producing unfavourable conditions for the formation of intense dust-storms. In addition, the very strong winds associated with intense cyclones and anticyclones were not apparent and the systems shifted northward during the spring. As a result, the frequency and intensity of observed dust-storms in 2003 in this region were very low. This confirms that there is variability in the frequency of dust-storm formation due to the current process of desertification and climate change. [ABSTRACT FROM AUTHOR]

A discriminate analysis method for probability forecast of dust storms in Mongolia has been developed. The prediction method uses data recorded at 23 meteorological stations in the Gobi and steppe regions of Mongolia, including surface air pressure and geo-potential height at the 500-hPa level on grid points, and weather maps from 1975 to 1990. Weather elements such as air temperature, pressure, geo-potential height etc, which influence the formation of dust storms, are prepared as predictors. To select the most informative/important predictors (variables), we used a mean correlation matrix of variables together with the Mahalonobis distance, and correlation coefficients between dust storms and predictors with an orthogonalization for removing correlated predictors. The most informative predictors for dust storm prediction are intensities of surface cyclones and migratory anticyclones, passage of cold fronts, the horizontal gradients of the surface air pressure in the cold frontal zone, cyclonic circulations from the ground surface up to the 500-hPa level, the geo-potential height at 500-hPa level and its temporal changes. Selected predictors are used in discriminate analysis for formulating dust storm prediction equations. Sandstorm data have been classified into three classes, viz., strong, moderate and weak dust storms, depending on their intensities, durations and areas covered. Predictions of the probabilities of dust storm occurrence use the prediction equations for each class. The prediction is made from 12 hours to 36 hours. Verification of the probability forecasts of dust storms is also shown. The accuracy of forecasts is 72.2–79.9% with the data used for developing equations (dependent variables), in contrast to 67.1–72.0% with unrelated data for deriving equations (independent variables). [ABSTRACT FROM AUTHOR]

Plutonium ( 238 Pu and 239,240 Pu), 137 Cs and plutonium activity ratios ( 238 Pu/ 239,240 Pu) as did uranium isotope ratio ( 235 U/ 238 U) were measured in surface soil samples collected in southeast Mongolia. The 239,240 Pu and 137 Cs concentrations in Mongolian surface soils (<53 μm of particle size) ranged from 0.42 ± 0.03 to 3.53 ± 0.09 mBq g −1 and from 11.6 ± 0.7 to 102 ± 1 mBq g −1 , respectively. The 238 Pu/ 239,240 Pu activity ratios in the surface soils (0.013–0.06) coincided with that of global fallout. The 235 U/ 238 U atom ratios in the surface soil show the natural one. There was a good correlation between the 239,240 Pu and 137 Cs concentrations in the surface soils. We introduce the migration depth to have better understanding of migration behaviors of anthropogenic radionuclides in surface soil. We found a difference of the migration behavior between 239,240 Pu and 137 Cs from 137 Cs/ 239,240 Pu – 137 Cs plots for the Mongolian and Tsukuba surface soils; plutonium in surface soil is migrated easier than 137 Cs. [ABSTRACT FROM AUTHOR]

Abstract: Atmospheric pollution caused by airborne particulate matter in the winter season in Ulaanbaatar, Mongolia is a very serious problem. However, there is a complete lack of scientific observation data to define the situation prior to any remediation. PM10 and PM2.5 average monthly values obtained by continuous monitoring showed the concentrations of particles of both size categories exceeded 100 μg m−3 during November to February (winter). PM10 particles were sampled with filters in January (i.e. during the heating period) and June (i.e.non-heating period) of 2008 in central Ulaanbaatar. To determine the composition of urban airborne particulate matter we analyzed a range of ionic components, multiple elements including heavy metals, and organic and inorganic carbon (soot). We also measured the stable carbon isotope ratio of the soot. Total carbon (sum of organic carbon and inorganic carbon) accounted for 47% of the mass of the PM10 during the heating period and 33% during the non-heating period, and was the largest component of urban airborne particulate matter in Ulaanbaatar. Stable isotope ratios (δ13C) of soot generated during the heating period (−23.4 ± 0.2‰) approximated the ratios for coal used in Ulaanbaatar (−21.3 to −24.4‰), while the ratios during the non-heating period (−27.1 ± 0.4‰) were clearly different from the coal values. In the heating period, a very high correlation was observed between soot and organic carbon, SO4 2–, NO3 −, F−, Zn, As, and Pb, and we concluded that they were derived from coal combustion along with soot. In addition, the concentrations and their ratios relative to each other of Al, Fe, Ca, K, Na, Mg, and Mn hardly differed between the heating period and the non-heating period, and it was concluded that they were derived from soil dust. [Copyright &y& Elsevier]

The COVID-19 pandemic could increase violence against children at home. However, collecting empirical data on violence is challenging due to ethical, safety, and data quality concerns. This study estimated the anticipated effect of COVID-19 on violent discipline at home using multivariable predictive regression models. Children aged 1–14 years and household members from the Multiple Indicator Cluster Surveys (MICS) conducted in Nigeria, Mongolia, and Suriname before the COVID-19 pandemic were included. A conceptual model of how the COVID-19 pandemic could affect risk factors for violent discipline was developed. Country specific multivariable linear models were used to estimate the association between selected variables from MICS and a violent discipline score which captured the average combination of violent disciplinary methods used in the home. A review of the literature informed the development of quantitative assumptions about how COVID-19 would impact the selected variables under a "high restrictions" pandemic scenario, approximating conditions expected during a period of intense response measures, and a "lower restrictions" scenario with easing of COVID-19 restrictions but with sustained economic impacts. These assumptions were used to estimate changes in violent discipline scores. Under a "high restrictions" scenario there would be a 35%–46% increase in violent discipline scores in Nigeria, Mongolia and Suriname, and under a "lower restrictions" scenario there would be between a 4%–6% increase in violent discipline scores in these countries. Policy makers need to plan for increases in violent discipline during successive waves of lockdowns. [ABSTRACT FROM AUTHOR]