gleb_etal2003.htm

Bulletin of Glaciological Research 20 (2003) 1-6
©Japanese Society of Snow and Ice

Evaluation of glacierized area of mountainous river basin in transition

Gleb E. GLAZIRIN and Yuji KODAMA
Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819 Japan

Abstract

　Glaciers continuously change in response to varying climate and they are always in transition. This study presents a method to estimate long-term change, with annual resolution, of the equilibrium line altitude (ELA) and area of transient glacierization (the covering of large land area by glaciers) of river basins. In this analysis, a glacierized area rather than area of individual glaciers, was examined. Two ELAs were introduced: adjusted ELA (AELA) and calculated zero balance altitude (CZBA). The AELA of an inventory year was obtained as the converged value of individual glaciers’ ELA when the ELAs were plotted against the area of individual glaciers. The CZBA was calculated as an altitude of zero annual specific mass balance, combining the empirical formulae for precipitation and ablation. The rate of change in AELA of glacierization was assumed to be proportional to the difference between the AELA and the CZBA. The series of AELA and area of glacierization were obtained using glacier inventory data of three years and the series of annual precipitation and summer (JJA) mean air temperature at a near by station by minimizing the mean squared error sum for the three glacier inventory years. The glacierized area was calculated using an empirical formula, which relates the glacierized area with the area of river basin above the AELA. The method was applied to four river basins in the Pamirs for the period from 1954 to 1980. The change of AELA was much smoother than CZBA. Our method can be used to predict future change of the equilibrium line altitude and the glacierized area from at least three glacier inventories taken over time and projected meteorological data.