Comparison of Cloud Characteristics Between Typhoon Lekima(1909) and Typhoon Yagi(1814)

Abstract

Previous studies show that two typhoons with similar landing area and similar moving tracks may have significant differences in precipitation intensity, which are caused by different structure and characteristics of the cloud systems. Based on FY-2H, Aqua, CALIPSO(Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) and GPM(Global Precipitation Measurement) satellite data, the horizontal and vertical structural characteristics of the cloud system, 3-dimensional structure and characteristics of Typhoon Lekima(1909) and Typhoon Yagi(1814), which landed along the Wenling coast of Zhejiang Province, are discussed.The visibility of typhoon eye area and the helicity of typhoon cloud system in TBB images are important indicators of typhoon development. The precipitation near the typhoon center is the largest, and the spatial distribution of typhoon precipitation is asymmetrical. For the typhoons with similar paths, strong typhoon induces circular strong precipitation center, while weak typhoon is along with belt-type strong precipitation center. In the mature stage of typhoon development, the maximum cloud top height is near the typhoon eye. When the cloud top height on the north side of the spiral rain belt area is lower than that on the south side, the typhoon develops strongly. When the cloud top height on the south side of the spiral rain belt area is lower than that the the north side, the typhoon is relatively weak. Before typhoon landing, the proportion of single layer cloud is higher when the typhoon is stronger, and the atmosphere is optically thicker. Typhoon clouds are mainly deep convective clouds and cirrus clouds consisting of non-directional ice. The height of cloud base and thickness in spiral rainband are related to the development of typhoon. Before typhoon landing, the area of high and low brightness temperature under the same channel, the precipitation type of typhoon, the length and number of convective columns in the 3-dimensional precipitation structure, and the precipitation rate in vertical direction can all indicate the development of typhoon. Regardless the typhoon strength, the total amount of ice water particles is roughly the same, and the difference in intensity is reflected in the areas of the high and low brightness temperature under the same channel. The spiral rain belt of a strong typhoon is dominated by stratiform precipitation, while a weak typhoon is dominated by convective precipitation. The number and length of convective columns of a strong typhoon are far greater than those of a weak typhoon.

Keywords

• similar track typhoon