APPLICATIONS OF THE CLOUDSAT TROPICAL CYCLONE PRODUCT IN ANALYZING THE VERTICAL STRUCTURE OF TROPICAL CYCLONES OVER THE WESTERN PACIFIC

Abstract:

Cloud profiling radar (CPR) onboard CloudSat allows for deep penetration into dense clouds/precipitation. In this study, tropical cyclones (TCs) are classified into three stages as developing, mature, and decaying. The circular TC area with the radius of 500 km is divided into five regions. The vertical structure characteristics of 94 Western Pacific TCs at different stages in different regions from June 2006 to February 2014 are statistically quantified using the CloudSat tropical cyclone overpass product (the CSTC Product). Contoured frequency by altitude diagrams (CFADs) of radar reflectivity show an arc-like feature and exhibit opposite distributions with a boundary at 5 km. Bright bands are found at this altitude, indicating melting layers. Deep convective (DC) clouds have the largest occurrence probability in the inner region, while Ci clouds occur more frequently in the outer region at 10-15 km. As clouds have the second largest vertical scale after DC clouds. Distributions of Ac, Cu, and Ns clouds at different stages have few distinctions. As the altitude increases, the ice effective radius and the distribution width parameter decrease while the particle number concentration increases. Moist static energy (MSE), cloud thickness (CT), liquid water path (LWP), ice water path (IWP), water vapor (WV), and rain rate (RR) all diminish along the radial direction and are significantly larger at the mature stage. The average value of MSE at the developing stage is larger than that at the decaying stage.