Characterization of contemporary aeolian dust deposition on mountain glaciers of western China

From 2008 to 2010, a total of 15 snow pit samples were collected from 13 mountain glaciers in western China. In this study these samples are used to determine the spatial distribution of insoluble particle concentrations and dust deposition fluxes in western China. The results show that the mass concentrations of insoluble particles exhibit high spatial variation and strongly decrease （by a factor of approximately 50） from the north （Tienshan Mountains） to the south （Himalayas）. However, the insoluble particles concentrations at the southeastern Tibetan Plateau （TP） sites are also high and ap- proximately 30 times greater than those in the Himalayas. The spatial distribution of the dust flux is similar to that of the mass concentrations; however, the high dust deposition rate in the southeastern TP is very significant as a result of the extensive snow accumulation （precipitation） in this region. The average sizes of the insoluble particles at each site generally exhibit bimodal distributions with peaks at approximately 5 μm and 10 μm, which can be explained as re- sulting from dust emissions from regional and local sources, respectively. The enrichment factors for most of the elements measured in insoluble particles are less than 10 at all of the study sites, indicating primarily crustal sources. However, the sites located in the peripheral mountains of western China, such as the Tienshan Mountains and the Himalayas, are characterized by high levels of certain enrichment elements （e.g., Cu, Zn, Cr, and V） indicative of sources related to the long-range transport of pollutants.

Shifts in water-level variation of Namco in the central Tibetan Plateau from ICESat and Cryo Sat-2 altimetry and station observations

The dynamics of high-altitude inland lakes in the Tibetan Plateau are sensitive indicators of climate change. Due to the remoteness and hard access, satellite altimetry becomes an effective approach to obtaining largescale and temporally continuous information of lake-level changes. The Cryo Sat-2 altimetry is expected to solve the current problem that earlier radar altimeters are only practical for monitoring large water bodies, while ICESat laser altimetry is available only for the period 2003–2009.In this study, the comparison of Cryo Sat-2 altimetry for Namco with in situ water-level data suggests a high correlation coefficient of 0.71(P \ 0.01), with the mean error of-0.12 m and root-mean-square error of 0.18 m. Further,the combination of ICESat and Cryo Sat-2 altimetry data and in situ lake-level observations reveals a rapid waterlevel rise of 0.24 ± 0.04 m/year during 2003–2008 and then a slightly decreasing trend of-0.09 ± 0.04 m/year during 2009–2013. This study suggests that the Cryo Sat-2altimetry has the potential of sustaining the fine observations on Tibetan lakes, following the ICESat mission.Besides, the examination of four key climatic variables(temperature, precipitation, potential evapotranspiration,and relative humidity) during 1990–2013 indicates that thewetting climate over Namco Basin stagnated or even reversed around 2006, which may be tightly related to the slowing lake growth.