青藏高原积雪被动微波遥感资料与台站观测资料的对比分析

积雪资料的可靠程度在反映积雪变化、预估后期气候变化时非常重要, 利用青藏高原74个气象台站资料与被动微波遥感资料进行对比分析. 结果表明: 两种积雪资料在高原南部边缘、高原东部唐古拉山与念青唐古拉山东部均表现为高值区, 在柴达木盆地、高原腹地及沿雅鲁藏布江一线表现为一致的少雪区,在青海南部和藏东南地区差异较大.遥感资料的积雪深度和积雪日数变化敏感区与台站观测资料存在差异.在积雪的显著季节性特征及气候尺度上的年际变化特征方面, 遥感资料与台站资料具有很好的一致性, 但遥感资料在刻画积雪季节内波动特征方面欠佳, 且年平均积雪深度和积雪日数遥感数据偏大.对AMSR-E逐日积雪资料进行评价发现, 高原腹地总精度大于高原边缘地区, 海拔3 000 m以下的反演精度较高, 雪深在9~10 cm时的反演精度较高.

Analyses of Snow Cover Based on Passive Microwave Remote Sensing Data and Observed Data over the Tibetan Plateau

Reliability of snow cover data is the key factor to reflect the change of snow cover and to predict the climate change. Based on the observed snow data from 74 weather stations, the snow data accuracy from passive microwave remote sensing over the Tibetan Plateau was analyzed. The results show that both passive microwave remote sensing data and observed data reveal high seasonal snow cover regions in the southwestern edge of the plateau and in the east of the Tanggula Range and the Nyainqêntanglha Range. Less seasonal snow cover regions are the Qaidam Basin and the hinterland of the plateau and along the Yarlung Zangbo River. Snow cover has a significant difference between the south of Qinghai Province and the southeast of the plateau. There is a good consistent between passive microwave remote sensing data and observed data in significant seasonal characteristics and annual variations of snow cover. However, the remote sensing data do not describe the fluctuating characteristics within a season very well. Annual mean snow depth derived from passive microwave remote sensing data seems larger than that from weather station's data. Looking from the daily snow depth data of AMSR-E, it is found that the accuracy of snow cover in the plateau hinterland is higher than that in the plateau margin. Also, the accuracy is higher in the regions below 3 000 m a.s.l. and when snow depth is 9~10 cm.