中文摘要：

2008年初,我国南方出现了罕见的大范围低温雨雪冰冻天气灾害。在整理灾害过程期间南方地区冻雨天气探空曲线后,发现我国东部低海拔地区冻雨天气的发生机制与高海拔的贵州中西部冻雨天气的发生机制有所不同。我国南方地区由于处于低纬度地区,地面积雪多为湿雪、薄雪。雪内少量液态水就能导致微波亮温值急剧上升,大大改变雪层观测辐射信号。利用南方地区积雪冻融变化时微波亮温昼夜之间的差异变化,使用被动微波数据（SSM/I）建立了一种针对低纬度南方地区积雪监测的补充方法,从而可以获得更加完整的低纬度地区积雪覆盖图像。

英文摘要：

A rarely severe cryogenic freezing rain and snow disaster occurred in widespread southern China from January to early February in 2008.According to the thermosonde curves,it appears that the mechanism of freezing-rain in the eastern China is different from that in mid-western Guizhou with high-altitude.Most snow cover in the low-latitude southern China is thin and wet.A little liquid water in snow could sharply raise the microwave brightness temperature,therefore change the radiation signal.Based on the variation of brightness temperature value between day and night during snow freezing-thawing process in southern China,a compensating way of snow monitoring in lower latitude was built by using the passive microwave data（DMSP-SSM/I）,which combined with other snow remote sense products could offer more information about snow distribution.