利用卫星数据分析青藏高原云微物理特性

Analysis on Cloud Microphysical Property over Qinghai-Xizang Plateau Using Satellite Data

青藏高原(下称高原)对东亚大气环流、气候变化及灾害性天气的形成和发展都有重要的影响。首先比较了不同空间分辨率数据对云微物理特性分析结果的影响,结果表明,在整体区域性变化分析中,利用0.01°×0.01°高空间分辨率的MODIS数据和2.5°×2.5°低空间分辨率的ISCCP数据所反映的云特性变化趋势相当。与ISCCP资料相比,高空间分辨率的MODIS资料可以更多地反映出云的局地性特征。其次,利用近10年高空间分辨率的卫星资料分析了高原云微物理特性的时空变化,结果表明,近10年高原上云的光学厚度有减小的趋势,云水路径的年、季变化有少许波动,但多年变化没有明显趋势。在空间分布上,高原云光学厚度和云水路径从东南向西北减少,充分反映了高原西北部干旱少雨,东南部湿润多雨的事实。

The unique topography of the Qinghai-Xizang Plateau throws a great impact on ambient cir- culation, climate changing and the evolution of severe weather in East Asia. Many researches obtained some valued results using either ground based observation data or satellite data. But it is worth noting that there are less ground observation stations and unevenly distributed. The satellite observation is a good supplement for ground based observations. However, most research used ISCCP data that its spatial reso- lution is only 2. 5° × 2. 5°. It canr t explain cloud properties related to complex surface properties. This study first compared the different spatial resolution data on the results of the analysis of cloud properties. The results showed that the cloud has the similar change trend using either MODIS data with 0.01°× 0.01° resolution or ISCCP data with 2.5°× 2.5° resolution. Comparing with ISCCP data, MODIS data can show more local characteristics of cloud. Then the cloud properties were analyzed over the Qinghai-Xizang Plat- eau using EOS/MODIS data with 1 km spatial resolution in past 10 years. The results show that the cloud optical thickness tends to decrease in past 10 years. At the same time, the cloud liquid water path changes slightly fluctuations in season, but there is no significant change in the trend for many years. From the spatial distribution, the cloud optical thickness and cloud water path over the Qinghai-Xizang Plateau de- crease from southeast to northwest, and fully reflects the fact that there is drought in northwest part of the Qinghai-Xizang Plateau and is humid and rainy in southeastern part of the Qinghai-Xizang Plateau