摘要
中国西部天山乌鲁木齐河源1号冰川上的消融和热量平衡研究是在冰川消融区中部海拔高度3895m的平坦雪面上进行的。观测场中的粒雪由两个不同层次的清洁粒雪和包含来自沙漠地区尘暴的污化粒雪所组成。当下部污化层在表层出露时,冰川自然表面的反射率则产生急剧的变化。当反射率从0.67降低至0.52时,相应的吸收辐射量将随之增加47％。根据1983年7月5日至25日的观测资料,对具有代表性的各天气情势下的热量平衡各组成分量的计算表明,在热量收入部分中,净辐射供热占71.6％5.40MJ/m^2·d),感热供热占28.4%(2.15MJ/m^2·d)。在热量支出部分中,消融耗热占94.8％(-6.79MJ/m^2·d),潜热占5.0％(-0.36MJ/m^2·d),其余0.2％(-0.013MJ/m^2·d)的热量用于冰雪层中的热传导。以热量耗散形式出现的潜热意味着蒸发抑制了凝结作用。这是因为该区相对的低温和较低的湿度的缘故。在夏季,尽管平均日总量为0.013g/cm^2的蒸发在年物质平衡中所造成的物质亏损似乎是不太重要的,然而它却是制约该区冰川分布的重要因子。
Ablation and heat balance study were made on the ablation area of No. 1 Glacier at head of Urumqi River, Tianshan Mountains, Western China. The height of the observation site was 3895 m a. s. 1. which was approximately in the middle of ablation area and the observation lasted from July 5 to 25. The firn snow at the site during this period consisted of two different layer, upper one of clean granular snow and lower layer of dirty granular snow containing desert origin dusts. The surface albedo changed drastically when the lower layer appeared at the surface. The calculation of heat balance components show that in the heat source part, net radiation contributed 71.6% and sensible heat 28.4%. In the heat sink part melting contributed 94.8% and latent heat 5.0%. Latent heat in the heat sink part means that evaporation overwhelmed condensation. This is due to the relatively low temperature and low humidity in this region. Mass loss due to evaporation in summer does not seem to be important in the annual mass balance but it seems to be an important factor in determining the glacier distribution in this area.
出处
《冰川冻土》
CSCD
北大核心
1989年第4期298-310,共13页
Journal of Glaciology and Geocryology
基金
中日合作<天山冰川对气候变化的响应研究>课题
