西北太平洋上一个爆发性气旋的云系特征分析

Characteristics of Clouds Associated with an Explosive Cyclone over the Northwestern Pacific Ocean

本文利用CloudSat卫星数据处理中心(CloudSat Data Processing Center, CloudSat DPC)提供的CloudSat卫星资料、欧洲中期天气预报中心(European Centrefor Medium-Range Weather Forecasts, ECMWF)提供的ERA5再分析资料、美国国家航空航天局(National Aeronautics and Space Admin-istration, NASA)提供的Aqua卫星可见光云图,对2019年2月28日至3月5日发生在西北太平洋上一个爆发性气旋(EC)个例四个阶段云系的宏观形态和微物理学特征进行了分析。结果表明,自EC的发生至消亡阶段,云的宏观形态先从不规则形状发展成紧凑的螺旋状,随后云系面积逐渐扩大直至消散。EC在不同阶段云的微物理学特性的水平分布特征较为一致,但其他方面却存在较大差异。在气旋成熟阶段,在其中心北部云的冰水路径和雪水路径有一个大值中心,与“暖核”位置相对应,但液态水路径无大值中心,云的雨水路径的大值则主要分布于气旋南部和东部。EC在不同阶段,云的微物理学特性垂直分布有如下特征:云的冰水含量分布呈“三层模型”分布,但云的其他微物理量随高度增加逐渐减小。总体而言,EC在不同阶段的云系呈现“零散”至“规则”再到“零散”的分布特征。

This paper investigates the characteristics of clouds associated with an explosive cyclone (EC) which occurred over the Northwestern Pacific from 28 February to 5 March 2019, by using the CloudSat satellite data obtained from the CloudSat Data Processing Center (CloudSat DPC), ERA5 reanalysis data from the European Centre for Medium-Range Weather Forecasts (ECMWF), and Aqua satellite visible imagery provided by the National Aeronautics and Space Administration (NASA). The mac-ro-features and microphysical characteristics of the clouds associated with this EC were documented. It was shown that the outer macro-shapes of the clouds developed from irregular shape to compacted spiral-shape, and the cloud area expanded gradually until the EC dissipated. The horizontal distribution of microphysical characteristics of clouds associated with the EC at different stages was consistent, but there exited significant differences in other aspects. At the mature stage of EC, there were large value centers for cloud ice water path and snow water path in the north of EC, respectively, corresponding to the “warm core” position, but there was no large value center for cloud liq-uid water path. The large cloud rain water path was mainly located in the south and east of the EC. At different stages of EC, the vertical distribution of microphysical characteristics of cloud presented the following characteristics: the distribution of cloud ice water content displayed a “three-layer-model” pattern. But, the other cloud microphysical properties gradually decreased with the height increasing. In general, the cloud patterns associated with EC at various stages exhibited different distributions from “scattered-shape” to “regular-shape”, and then to “scat-tered-shape”.