A Summary of 40-Year Observed Variation Facts of Climate and Glacier No.1 at Headwater of rümqi River,Tianshan,China
LI Zhong qin, HAN Tian ding, JIN Zhe fan, YANG Hui an, JIAO Ke qin(Tianshan Glaciological Station, CAREERI, CAS, Lanzhou Gansu 73000, Chi na)
Comprehensive, Glacier No.1 centered o bservations are conducted at headwater of rümqi River by Tianshan Glaciological Station since 1959.This paper presents analyses of mass balance, terminus, area and surface velocity histories of Glacier No.1, and as well as spatial distributed streamflow and climate factor (air temperature and precipitation) records from nearby area. Our study demonstrates that the continuous local annual temperature rising, resulting in reduction of cooling energy in the glacier, might be responsible for recent acceleration of glacier melting. The headwater region of rümqi River is experiencing a warm and humid period ever sine the mid-90s. From 1958 to 2000, with an average annual balance -188.6 mm (about -34.6×10 4 m 3 in volume), the cumulative balance of Glacier No.1 is reach u p to -7 925 mm(1 452×10 4 m 3 ), in other words, the thickness of the glacier stream decreased by more than 8m over the past 42 year span. With an accelerated shrinking tendency, the glacier area decreased by 11% from 1962 to 2001. The terminus of the glacier is in the state of retreat since it has been observed from 1960s. From 1962 to 2001 East Branch retreated 168.95 m, whilst West Branch retreated 185.23 m. In agreement with ice mass losing, surface velocity of the glacier is appreciably slowing down. By using water balance model, annual meltwater runoff of the glacier has been computed sine 1958. It shows an elevated trend, especially after 1985. The mean meltwater runoff depth from 1986-2001 is 936.6 mm, comparing to 508.4 mm from 1958 to 1985, it increased by 84.2%.