科其喀尔巴西冰川的近地层基本气象特征

Near-Surface Meteorological Characteristics on the Koxkar Baxi Glacier,Tianshan

利用2003—2006年天山托木尔峰地区科其喀尔巴西冰川的考察资料,对该冰川近地层的基本气象特征进行了分析.研究表明:冰川从4月中下旬开始即有明显消融,主消融期为5-9月,1月冰川区的气温最低.冰川中上部的气温直减率较小,说明该处的冰川冷效应较弱;而冰川下部较大的气温直减率,则可能主要与消融区连续的表碛覆盖有关.5-9月集中了全年约75%的降水,而冬季的降水稀少.降水的分布存在明显的高低分带,低降水带位于冰川中上部的海拔3 700 m附近,而冰川末端和冰川上部的降水量较大.受地形和下垫面条件的影响,冰川下部的山谷风非常发育,而冰川上部局地环流较弱.

Based on the scientific expedition carried on Koxkar Baxi Glacier, Tomur Peak, 2003-2006, the near-surface meteorological characteristics of the Koxkar Baxi Glacier are analyzed and discussed in this paper. It is found that the glacier ablation starts from late April, while the main ablation period ranges from May to September. January is the coldest month in a year. The lapse rate of air temperature in the middle and upper parts of the glacier is small, reflecting a weak cooling effect in this region. The larger lapse rate in the lower part of the glacier, however, is supposed to be related with the broad supraglacial debris cover, Precipitation in the ablation period accounts for about 75% of the annual precipitation, and it is small in the winter. It is revealed that the precipitation around 3700 m a. s. l. is small, while in the terminus and the upper part of the glacier there are two larger precipitation zones. Depending on landform effect and land cover condition, the mountain and valley winds in the lower part of the glacier are strong, while in the upper part of the glacier there is a weak local circulation.