Changes in Tropical Cyclone Precipitation Over China

In this paper, an objective technique for estimating the tropical cyclone precipitation (TCP) from station observations for China, which is called the Objective Synoptic Analysis Technique (OSAT), is proposed. As the OSAT technique is to imitate the process whereby a weather forecaster manually analyzes a synoptic map, OSAT shows a good ability to distinguish TC precipitation. To analyze the TC precipitation, OSAT takes two steps: separating independent rainbelts and distinguishing TC’s rainbelt (Fig. 1). First, based on the structure of precipitation distribution, the daily precipitation field can be separated into several independent rainbelts and some scattered precipitation stations. In this step, there are five substeps: computing raining rate of neighborhood station, selecting the most potential rainbelt centers, defining the main characteristics of a rainbelt, roughly defining edges of the L rainbelts, and carefully defining edges of the L rainbelts. Second, according to the relationships between the TC center and independent rainbelts and the scattered precipitation stations, the rainbelts associated with a TC can be determined. In this step, there are two substeps: selecting potential TC rainbelts and defining the whole TC rainbelt.