南疆沙漠腹地夏季晴天与沙尘日小气候观测对比分析

Contrast Analysis on Microclimate Characteristic of Clear Day and Sand-dust Day in Tazhong Station of Desert Hinterland of South Xinjiang in Summer

利用塔克拉玛干沙漠大气环境观测试验站2006年8月13—31日近地层微气象资料以及常规地面观测资料,选取晴天与沙尘日个例,采用波文比能量平衡方法,对比分析了晴天与沙尘日沙漠腹地的小气候和地表能量平衡特征。结果表明,晴天气温、地温日变化幅度均大于沙尘日,各深度地温极值出现时间滞后于沙尘日;晴天夜间近地层存在逆温,沙尘日具有等温性;晴天夜间比湿较大,白天较小,沙尘日夜间比湿变化平缓,在沙尘暴发生时,比湿急剧增大,并有弱的逆湿现象存在;沙尘日总辐射、反射辐射、净辐射和感热通量比晴天明显偏小,向下长波辐射却大于晴天,但潜热变化差异不太明显。

By using the micrometeorology data and conventional observation data from the Taklimakan desert atmospheric environment observation station on 13--31 August 2006, and choosing the case of typical clear day and sand day, the microclimate characteristic and ground surface energy balance of two different weather conditions in Taklimakan desert hinterland were comparatively analyzed with Bowen Ratio Heat Budget Method. The results show that there has a obvious difference in microclimate characteristic and ground surface energy balance between clear day and sand day. The diurnal variation in air temperature, humidity and sand layer temperature on clear day was larger than that on sand day. The temperature inversion occurred near the surface layer at night of clear day, the temperature increasing with the height within certain altitude range. However, it presented isothermal during the night of sand day, the temperature changed little with increasing height. Desert hinterland surface heat equilibrium was influenced greatly by sand weather. The global radiation, reflected radiation, net radiation and sensible heat flux of sand day were obviously smaller than those of clear day. But the atmosphere down long wave radiation was larger than clear day. No matter how for sand day or clear day, the latent heat variation difference was very small.