基于PR和VIRS融合资料的东亚台风和非台风降水结构分析

Characteristics of Typhoon Precipitation and Non-typhoon Precipitation over East Asia Based on Merged PR and VIRS Data

借助JAXA/EORC 热带台风数据集资料，实现了台风区和非台风区的分离，在此基础上，利用热带测雨卫星搭载的测雨雷达和可见光/红外扫描仪的融合观测资料，对1998～2007年东亚雨季台风及非台风降水的气候特征和降水云红外信号特征进行了分析。结果表明：1）东亚台风降水强度谱较非台风降水谱更宽，特别是对流降水主要分布在5～20 mm/h之间；强降水更多，主要分布在东亚洋面。2）雨季东亚降水的主要形式是非台风层云降水，但台风降水对局地降水量的贡献也不容忽视，例如台湾以东附近洋面可达20%。3）台风降水云亮温海陆分布差异显著；其雨顶高度在4～9 km（层云）和4.5～12.5 km（对流）之间均有分布，较非台风降水雨顶高度谱更宽。4）不同等级的台风在降水强度、覆盖区域和云顶10.8μm亮温分布上差异大。

Typhoon and non-typhoon regions were separated in this study by using the Tropical Cyclone database and merged data of the Tropical Rainfall Measuring Mission Precipitation radar （PR） and visible/infrared scanner from Japan Aerospace Exploration Agency/Earth Observation Research Center （JAXA/EORC）. The characteristics of typhoon and non-typhoon precipitation and their infrared signals were then analyzed over East Asia during the rainy season from 1998 to 2007. The distribution of typhoon rainfall intensity was shown to be significantly wider than that of non-typhoon, particularly for convective rainfall ranging from 5 mm/h to 20 mm/h. Strong typhoon rainfall occurred mainly over the ocean in East Asia. Although the main form of precipitation over East Asia is non-typhoon stratiform precipitation, the contribution of typhoon precipitation to the total precipitation can reach 20%in the east area of Taiwan and thus cannot be ignored. Storm heights of typhoon precipitation show distinguished land–sea distribution differences ranging from 4 km to 9 km for stratiform precipitation and 4.5 km to 12.5 km for convective precipitation. These results are much wider than those of non-typhoon precipitation. Moreover, the conditional rain rate, covering area, and brightness temperature at 10.8 gm differs significantly for typhoon precipitation of various intensity periods.