Atmospheric dust aerosols over the Eastern Pamirs: major element concentrations and composition

This study measured the major element concentrations and compositions of atmospheric dust aerosol samples collected weekly for nearly 2 years at Mt. Muztagata, a remote and high-elevation site (38°17′N, 75°01′E, 4,430 m) in the Eastern Pamirs. Inductively coupled plasma mass spectroscopy (ICP–MS) results show that on the weekly timescale, air at Muztagata contained average element Al concentrations of 842 ng m⁻³ between June 2004 and December 2005, and 509 ng m⁻³ between June 2005 and April 2006. The dust load over the Eastern Pamirs appears to be far lower (by more than an order of magnitude) than those in northern China. The Muztagata dust aerosols show Ca/Al ratios (~0.7) and Fe/Al ratios (~0.7) that differ from that in northern China. The general homogeneity exists in the major element compositions, expect Ca/Al ratios which show minor but clear seasonal variations. Element ratios vary with aerosol concentration. Results indicate that concentrations and compositions of Asian dust change significantly between different emission regions, and confirm that major element ratios can be used to efficiently characterize the dust aerosols composition at different sites in northern China.     

一种新的混合迭代UKF

从统计线性回归的角度对无味变换(unscented transformation,UT)进行分析,推导了迭代无味卡尔曼滤波(iterated unscented Kalman filter,IUKF)。针对IUKF计算量大的问题,结合弦线迭代法和IUKF,得到了一种新的混合迭代无味卡尔曼滤波器。数值仿真的结果表明,新滤波算法的精度优于扩展卡尔曼滤波、迭代扩展卡尔曼滤波和无味卡尔曼滤波,并可以有效降低IUKF的计算量。     

Variations of near-surface atmospheric CO_2 and H_2O concentrations during summer on Muztagata

1 Introduction As one of the most important greenhouse gases, atmospheric carbon dioxide (CO2) has increased in concentration rapidly since preindustrial times[1―4] and significantly contributes to the climate change[5] caused by anthropogenic emissions. Documentation of the global carbon cycle has been critical for under-standing the causative relationships between green-house gases and climate change. For example, the CO2 level in the atmosphere has been monitored at many sites worldwide …     

Vertical quantitative and dominant population distribution of the bacteria isolated from the Muztagata ice core

With rapid development of microbiology on ex-treme environment, many microorganisms have been found on glacial surface and in deep glacier around the world. The extensive 16S rRNA sequence analysis of bacteria isolated from glacial samples indicates that the bacteria in ice are highly similar to those from ocean, lake, terrestrial sediment and agricultural soil on the earth[1,2]. This suggests a close relationship be-tween the microorganisms in glacial region and those in other environments s…     

An Overview of the Studies on Black Carbon and Mineral Dust Deposition in Snow and Ice Cores in East Asia

Black carbon （BC） is the most eff ective insoluble light-absorbing particulate （ILAP）, which can strongly absorb solar radiation at visible wavelengths. Once BC is deposited in snow via dry or wet process, even a small amount of BC could signifi cantly decrease snow albedo, enhance absorption of solar radiation, accelerate snow melting, and cause climate feedback. BC is considered the second most important component next to CO2 in terms of global warming. Similarly, mineral dust （MD） is another type of ILAP. So far, little attention has been paid to quantitative measurements of BC and MD deposition on snow surface in the midlatitudes of East Asia, especially over northern China. In this paper, we focus on reviewing several experiments performed for collecting and measuring scavenging BC and MD in the high Asian glaciers over the mountain range （such as the Himalayas） and in seasonal snow over northern China. Results from the surveyed literature indicate that the absorption of ILAP in seasonal snow is dominated by MD in the Qilian Mountains and by local soil dust in the Inner Mongolian region close to dust sources. The detection of BC in snow and ice cores using modern techniques has a large bias and uncertainty when the snow sample is mixed with MD. Evidence also indicates that the reduction of snow albedo by BC and MD perturbations can signifi cantly increase the net surface solar radiation, cause surface air temperature to rise, reduce snow accumulation, and accelerate snow melting.     

Heavy metals in aerosol samples from the Eastern Pamirs collected 2004–2006

This study measured the concentration of heavy metal elements in atmospheric aerosol samples collected between July 2004 and April 2006 at a remote site on Mt. Muztagata (38°17'N, 75°01'E, 4430 m), in the Eastern Pamirs. Inductively coupled plasma mass spectroscopy (ICP–MS) results show that the air at Muztagata contains low concentrations of As and heavy metal elements (Cr, Ni, Cu, Zn, Cd, Pb, and Bi), comparable with those in the Arctic — far lower than in heavily populated or industrialized areas. Observed enrichment factor (EF) values greater than 10 for those elements suggest partly anthropogenic sources. Seasonal variations in the concentrations of Zn, Cd, Pb, Bi, and As resemble those of crustal Al, with greater concentrations during the summer but lower ones in winter. Our results reveal that the background atmosphere in remote inner Asia is only weakly affected by anthropogenic pollution, and demonstrate that high heavy metal concentrations occur during summer but with greater EF values during the winter. The air mass back-trajectory analyses suggest that pollution from West Asia, Central Asia, and South Asia are the main possible source areas that contribute to the heavy metals in aerosols at Muztagata.     

Measuring and modeling black carbon (BC) contamination in the SE Tibetan Plateau

Black carbon (BC) concentrations were measured in the southeast (SE) Tibetan Plateau along the valley of the Yarlung Tsangpo River during winter (between November, 2008 and January, 2009). The measured mean concentration (0.75 μg m⁻³) is significantly higher than the concentrations (0.004–0.34 μg m⁻³) measured in background and remote regions of the globe, indicating that Tibetan glaciers are contaminated by BC particles in the Plateau. Because BC particles play important roles for the climate in the Tibetan Plateau, the sources and causes of the BC contamination need to be understood and investigated. In this study, a mesocale dynamical model (WRF) with BC particle modules is applied for analyzing the measurement. The analysis suggests that the major sources for the contamination in the SE Plateau were mainly from the BC emissions in eastern Indian and Bangladesh. Because of the west prevailing winds, the heavy emissions in China had no significant effects on the SE Plateau in winter. Usually, the high altitude of the Himalayas acts a physical wall, inhibiting the transport of BC particles across the mountains to the plateau. This study, however, finds that the Yarlung Tsangpo River valley causes a 'leaking wall', whereby under certain meteorological conditions, BC particles are being transported up onto the glacier. This too causes variability of BC concentrations (ranging from 0.3 to 1.5 μg m⁻³) in a time scale of a few days. The analysis of the variability suggests that the “leaking wall” effect cannot occur when the prevailing winds were northwest winds, during which the BC transport along the valley of the Yarlung Tsangpo River was obstructed. As a result, large variability of BC concentration was observed due to the change of prevailing wind directions.     

http://www.sciencedirect.com/science/article/pii/S1674987112000023

Ice melt water from a 22.27 m ice core which was drilled from the East Rongbuk Glacier, Mt.Everest was incubation in two incubation ways:plate melt water directly and enrichment melt water prior plate,respectively.The abundance of cultivable bacteria ranged from 0-295 CFU mL^-1 to 0-1720 CFU mL^-1 in two incubations with a total of 1385 isolates obtained.Comparing to direct cultivation, enrichment cultivation recovered more bacteria.Pigment-producing bacteria accounted for an average of 84.9%of total isolates.Such high percentage suggested that pigment production may be an adaptive physiological feature for the bacteria in ice core to cope with strong ultraviolet radiation on the glacier.The abundances of cultivable bacteria and pigment-producing isolates varied synchronously along deplh:higher abundance in the middle and lower at the top and bottom.It indicated that the middle part of the ice core was hospitable for the microbial survival.Based on the physiological properties of the colonies,eighty-nine isolates were selected for phylogenetic analysis.Obtained 16S rRNA gene sequences fell into four groups:Firmicutes,Alpha-Proteobacteria,Gamma-Proteobacteria, and Actinobacteria,with the Firmicutes being dominant.Microbial compositions derived from direct and enrichment cultivations were not overlapped.We suggest that it is a better way to explore the cultiiiable microbial diversity in ice core by combining the approaches of both direct and enrichment cultivation.