MESOSCALE ANALYSIS ON RAINFALLS ASSOCIATED WITH TYPHOON SOUDELOR (1513) IN DIFFERENT STAGES

YE Long-bin; CHEN Yun; LI Sheng-qi; ZHU Jing

doi:10.16032/j.issn.1004-4965.2018.03.011

Abstract：Based on the FNL 1°×1° reanalysis data, hourly rainfall data, TBB data and radar reflectivities, this paper analyzes the characteristics, progressions of Mesoscale Convective Systems and environmental conditions of rainfall associated with typhoon Soudelor in different stages. Study shows that the torrential rainfall produced by Soudelor with the characteristics of intensity, long duration in land, wide coverage fields and so on. Most of precipitation concentrated on two stages: typhoon landing process and in combination with cold air. Both stages had great rainfall center in their areas. There were MCSs developing obviously in circulation cloud of Soudelor.Analyzing the environment conditions of Mesoscale Convective System, the result shows that: (1)The generation and development of MCSs in circulation cloud of Soudelor are the main reason that leaded the torrential rainfall. Great precipitation had happened in background which in combination with lower convergence and higher divergence. Abundant water vapor, orographic uplift and influence of cold air provided favorable conditions to the torrential rainfall. (2)The lower convergence airflow was enhanced by the terrain in the north fujian-south zhejiang area, and caused the development of MCSs by cooperating with higher divergence airflow. Most of water vapor concentrated on the north of typhoon body. The obviously asymmetric structure of Soudelor is the main reason lead the great rainfall center of first stage located in the north of typhoon body. (3)The interaction of cold air from the upper-troposphere trough and warm air from ocean in jiangsu-anhui area is the main reason leaded the development of MCSs and the torrential rainfall in second stage.