uetake_2006.htm

Bulletin of Glaciological Research 23 (2006) 85-93
©Japanese Society of Snow and Ice

Preliminary observations of sub-surface and shallow ice core at July 1st Glacier, China in 2002-2004

Jun UETAKE¹, Akiko SAKAI², Yoshihiro MATSUDA², Koji FUJITA², Hideki NARITA³,Sumito MATOBA³, Keqin DUAN⁴, Masayoshi NAKAWO⁵ and Tandong YAO⁶
1 Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Tokyo 152-8551, Japan
2 Graduate School of Environmental Studies, Nagoya University, Nagoya 464-8601, Japan
3 Institute of LowTemperature Science, Hokkaido University, Sapporo 060-0819, Japan
4 Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Science, Lanzhou 730000, China
5 Research Institute for Humanity and Nature, Kyoto 602-0878, Japan
6 Institute of Tibetan Plateau, Beijing 100085, China

Abstract

　 The albedo reduction on glacier surfaces in past summers due to microbiological activities and mineral particles should be considered to reconstruct precise fluctuation of glacier mass balance. However, there is little knowledge on preservation of the microorganisms and the mineral particles in glacier ice. In particular, influence of superimposed ice formation on these preservations is unknown. As the first step to understand the albedo reduction process and to reconstruct surface albedo changes on glaciers in northwestern China, where superimposed ice formation has an impact on glacier mass balance, we report the glacier surface level changes, seasonal and annual changes of stratigraphy and analyzed results of short ice cores at upper parts of the July 1st Glacier from 2002 to 2004. Surface melting on the glacier was accelerated by dark-colored materials composed of cryoconite and mineral particles. The glacier surface level was lowered year by year and ELA (Equilibrium Line Altitude) was much higher than that in the 1970s and 1980s. An ice core of 1.82m length included five cyanobacterial layers. As cyanobacteria growduring summer, these layers may be useful as markers for summer layers and allowto infer surface albedo changes in the past. Average annual snow mass balance estimated from the cyanobacterial peaks in the core is 313mm, which corresponds to the annual precipitation observed near the terminus of the July 1st Glacier. These results would open up the possibilities that we could reconstruct past mass balance and albedo effects.