祁连山老虎沟12号冰川近地层微气象特征分析

Analysis on Micrometeorological Characteristic in the Surface Layer of Laohugou Glacier No.12 in Qilian Mountains

利用2009年9月1日-2010年8月31日祁连山老虎沟12号冰川海拔4 550m气象观测资料,分析并讨论了气温、降水、比湿、气压、风速、风向、总辐射、感热和潜热通量的变化特征。结果表明,在冰川下垫面影响下,气温的逐时变化呈现出升温比降温要快,但季节变化则相反,气温变化的位相比风速要超前;降水主要集中在5～9月,占全年降水的68.1%;冬季平均风速最大,夏季最小,春季高于秋季,春、秋季冰川风的强度要大于谷风,夏季则相反,冬季冰川风占绝对主导地位,且冰川风对地气间的能量交换有重要影响;全年感热通量日平均值大部分都为正值,而潜热通量基本都为负值,在气温较高、风速较大的情况下二者均有明显的增加;夏季感热和潜热通量的绝对值都比冬季要大。

The micrometeorological variation characteristics,such as temperature,rainfall,specific humility,air pressure,wind,sensible heat flux,latent heat flux and so on,are analyzed based on the observed meteorological data from September 1,2009 to August 31,2010,at the elevation of 4 550 m of the Laohugou Glacier No.12 in Qilian Mountains.Due to the influence of the glacier underlying surface,the rising rate of hourly mean variations of temperature is larger than the decreasing rate,opposite to the seasonal variation.The phase variation of temperature is in advance of wind speed.Precipitation mainly concentrates from May to September,which is 68.1% of the annual amount.The mean wind speed is the largest in winter,the smallest in summer,and in spring it is above in autumn.The glacier wind is heavier than valley wind in spring and autumn,opposite to in summer.It governs in winter and plays an important role in energy exchanges in the land-surface process.The major portion of daily mean sensible heat flux is positive,and the latent heat flux is almost negative in all the year,which increase noticeably in the case of higher temperature and larger wind speed.The absolute values of sensible heat and latent heat fluxes in summer are larger than in winter.