天山南坡科契卡尔巴西冰川物质平衡初步研究

Preliminary Study of Mass Balance on the Keqicar Baxi Glacier on the South Slopes of Tianshan Mountains

基于2003—2005年考察期间观测的气温与降水资料,运用度日物质平衡模型模拟了天山南坡科契卡尔巴西冰川近期的物质平衡变化状况.结果表明:度日物质平衡模型模拟的冰川物质平衡值与实测值的变化趋势基本一致,模型模拟结果较为理想;2003/2004年度和2004/2005年度两个物质平衡年的平均物质平衡值分别为-494和-384 mm,平衡线高度(ELA)比20世纪70年升高了300 m左右.由此可见,在由暖干向暖湿转型的气候背景下,尽管降水增加显著,但强烈的升温导致科契卡尔巴西冰川处于强烈的物质亏损状态.

Since the late 1980s, there is a strong signal of climate shift from warm-dry to warm-humid in Northwest China. The mean air temperature of West China from 1987 to 2000 had increased by 0.7 ℃ as compared with the that from 1961 to 1986. With the rapid rising of air temperature, the annual mean precipitation during the period from 1987 to 2000 increased by 11% in northern Xinjiang and 320/60 in southern Xinjiang relative to that from 1960 to 1986 within the Tarim basin. In this paper, mass balance of the Keqicar Baxi Glacier in the Tarim River basin, Northwest China, is simulated under the condition of climate change, using a degree-day glacier mass-balance model. The glacier has detailed mass-balance measurement over the period 2003—2005. The modeling results are in good agreement with the measured variations in the mass balance changing with elevation during 2003—2005. The mean mass balance was —494 and—384 mm in the mass balance year of 2003—2004 and 2004—2005, respectively; compared to that in the 1970s, the equilibrium line altitude shifted up about 300 m. It can be seen that, though precipitation increases significantly, there is in the state of strong mass loss on the Keqicar Baxi Glacier due to the air temperature rising significantly. This study aims at providing a method for modelling the mass balance in the glacierised areas of the Tarim River basin, especially, in the non-monitored glacierised areas of Northwest China, as well as to assess the change in the cryosphere due to climate change.