Stable-Isotope and Trace Element Time Series from Fedchenko Glacier (Pamirs) Snow/Firn Cores

In summer 2005, two pilot snow/firn cores were obtained at 5365 and 5206 m a.s.l. on Fedchenko glacier, Pamirs, Tajikistan, the world\u27s longest and deepest alpine glacier. The well-defined seasonal layering appearing in stable-isotope and trace element distribution identified the physical links controlling the climate and aerosol concentration signals. Air temperature and humidity/precipitation were the primary determinants of stable-isotope ratios. Most precipitation over the Pamirs originated in the Atlantic. In summer, water vapor was re-evaporated from semi-arid regions in central Eurasia. The semi-arid regions contribute to non-soluble aerosol loading in snow accumulated on Fedchenko glacier. In the Pamir core, concentrations of rare earth elements, major and other elements were less than those in the Tien Shan but greater than those in Antarctica, Greenland, the Alps and the Altai. The content of heavy metals in the Fedchenko cores is 2-14 times lower than in the Altai glaciers. Loess from Afghan-Tajik deposits is the predominant lithogenic material transported to the Pamirs. Trace elements generally showed that aerosol concentration tended to increase on the windward slopes during dust storms but tended to decrease with altitude under clear conditions. The trace element profile documented one of the most severe droughts in the 20th century

Changes in atmospheric chemical composition determined from ice core records in southwestern Siberia during the 20th century /by Daniel R. Joswiak.

Thesis (Ph. D., Geography)--University of Idaho, September 2008

Monsoon-driven transport of organochlorine pesticides and polychlorinated biphenyls to the Tibetan plateau:three year atmospheric monitoring study

Due to the influence of the Indian monsoon system, air mass transport in and to the Tibetan Plateau shows obvious seasonality. In order to assess the responses of atmospheric concentrations of persistent organic pollutants (POPs) to the Indian Monsoon fluctuation patterns, a three year air monitoring program (2008–2011) was conducted in an observation station close to the Yarlung Tsangpo Grand Canyon, southeastern Tibetan Plateau. The air concentrations of polychlorinated biphenyls (PCBs) and hexachlorocyclohexanes (HCHs) are generally comparable to those of other remote regions, whereas the concentrations of DDTs are much higher than reported for the polar regions, the North American Rocky Mountains, and the European Alps. The concentrations of DDTs and PCBs were strongly linked to the cyclic patterns of the Indian monsoon, displaying higher values in the monsoon season (May–September) and lower values in the nonmonsoon season (November–March). A “bimodal” pattern was observed for α- and γ-HCH, with higher concentrations in spring and autumn and lower concentrations in the summer (monsoon season). Rain scavenging in the monsoon season likely resulted in the lower HCH concentrations in the atmosphere. This paper sheds lights on the role the Indian monsoon plays on the atmospheric transport of POPs to the Tibetan Plateau

Post-depositional enrichment of black soot in snow-pack and accelerated melting of Tibetan glaciers

The post-depositional enrichment of black soot in snow-pack was investigated by measuring the redistribution of black soot along monthly snow-pits on a Tien Shan glacier. The one-year experiment revealed that black soot was greatly enriched, defined as the ratio of concentration to original snow concentration, in the unmelted snow-pack by at least an order of magnitude. Greatest soot enrichment was observed in the surface snow and the lower firn-pack within the melt season percolation zone. Black carbon (BC) concentrations as high as 400 ng g(-1) in the summer surface snow indicate that soot can significantly contribute to glacier melt. BC concentrations reaching 3000 ng g(-1) in the bottom portion of the firn pit are especially concerning given the expected equilibrium-line altitude (ELA) rise associated with future climatic warming, which would expose the dirty underlying firn and ice. Since most of the accumulation area on Tibetan glaciers is within the percolation zone where snow densification is characterized by melting and refreezing, the enrichment of black soot in the snow-pack is of foremost importance. Results suggest the effect of black soot on glacier melting may currently be underestimated.</p

Monsoon-Driven Transport of Organochlorine Pesticides and Polychlorinated Biphenyls to the Tibetan Plateau: Three Year Atmospheric Monitoring Study

Due to the influence of the Indian monsoon system, air mass transport in and to the Tibetan Plateau shows obvious seasonality. In order to assess the responses of atmospheric concentrations of persistent organic pollutants (POPs) to the Indian Monsoon fluctuation patterns, a three year air monitoring program (2008–2011) was conducted in an observation station close to the Yarlung Tsangpo Grand Canyon, southeastern Tibetan Plateau. The air concentrations of polychlorinated biphenyls (PCBs) and hexachlorocyclohexanes (HCHs) are generally comparable to those of other remote regions, whereas the concentrations of DDTs are much higher than reported for the polar regions, the North American Rocky Mountains, and the European Alps. The concentrations of DDTs and PCBs were strongly linked to the cyclic patterns of the Indian monsoon, displaying higher values in the monsoon season (May–September) and lower values in the nonmonsoon season (November–March). A “bimodal” pattern was observed for α- and γ-HCH, with higher concentrations in spring and autumn and lower concentrations in the summer (monsoon season). Rain scavenging in the monsoon season likely resulted in the lower HCH concentrations in the atmosphere. This paper sheds lights on the role the Indian monsoon plays on the atmospheric transport of POPs to the Tibetan Plateau