As a receptor of atmospheric deposition, glaciers are considered an ideal archive in the study of climate change and geochemical cycles. The deposition of methanesulfonic acid (MSA) in the glaciers provides good opportunities to study the biogeochemical cycle of sulfur in the cryosphere. In the present work, snow samples were collected from six High Asia glaciers along a north-to-south transect to determine the spatial distribution of MSA and elucidate its potential sources. The median MSA concentration in the Urumqi Glacier No.1 of Tien Shan was 138.8 ng mL(-1), which was distinctly higher than those observed in the Tibetan Plateau (TP) glaciers and polar regions. The levels of MSA in the interior TP glaciers were higher than those observed in the margins of northeastern and southeastern TP. Good correlations between MSA and K+ (r = 0.86, n = 30, alpha = 0.01), Mg2+ (r = 0.86), and NH4+ (r = 0.73) were observed in continental glaciers. Principal component analysis indicated that MSA may have terrigenous material inputs. At Yulong Snow Mountain, MSA was correlated with Na+ (r = 0.76, n = 8, alpha = 0.1), a sea-salt tracer ion, suggesting that MSA may be derived from marine environments. According to dimethyl sulfide (DMS) production and NH3 emissions in High Asia, we deduced that the high concentrations of MSA in continental glaciers are possibly related to the sources of hypersaline soil environments and animal husbandry in nomadic areas. This work is useful for further studies on regional sulfur cycling and the impacts of human activities on climate change.

Since 2000, 18 High Asia glaciers have been surveyed for black carbon (BC) deposition 22 times, and numerous snow samples and ice cores have been collected by researchers. However, most of the results were interpreted individually in papers. Here, we assemble the data and discuss the distribution of BC deposition and its impacts on the melting of the glaciers through radiative forcing. We find that BC distribution on the surfaces of High Asia glaciers primarily depends upon their elevations (i.e., higher sites have lower concentrations) and then upon regional BC emissions and surface melting conditions. BC concentrations in High Asia glaciers are similar to the Arctic and western American mountains but are significantly less than heavy industrialized areas such as northern China. Although Himalayan glaciers, which are important due to their water resources, are directly facing the strong emissions from South Asia, their mean BC is the lowest due to high elevations. A new finding indicated by ice core records suggested that great valleys in the eastern Himalayan are effective pathways for BC entering the Tibetan Plateau and make increasing BC trends in the local glaciers. On average, BC deposition causes a mean forcing of similar to 6 Wm(-2) (roughly estimated 5% of the total forcing) in High Asia glaciers and therefore may not be a major factor impacting the melting of most glaciers. (C) 2012 Elsevier Ltd. All rights reserved.