Characteristics of intra-storm temporal pattern over China
摘要
To describe the characteristics of intra-storm temporal distributions of rainfall,minute resolution rainfall data were collected from 14 weather stations in China covering nearly 40 years. A total of 10 256 storms with precipitation amounts greater than 10 mm were analyzed. Based on a dynamic K-means cluster method and the time to peak index,the storms were divided into four hyetograph types: Rainfall concentrated early in the storm (Type I); rainfall concentrated in the middle of the storm (Type II); rainfall concentrated at the end of the storm (Type III); and rainfall distributed uniformly over time (Type IV). Type I storms occurred most frequently (47.1%),followed by Type II (21.2%),Type III (15.3%),and Type IV (16.4%). In summer,Type I storms had a normalized occurring frequency of 52.2%,suggesting that Type I storms were the most prevalent storm type during the summer. In winter,all four storm types occurred with similar frequencies. Type I storms were characterized by shorter durations and higher intensities,whereas Type IV storms had longer durations and lower intensities. The average duration,intensity,and the maximum 30 min intensity for Type I storms were 19.2 h,2.8 mmh,and 20.3 mmh,respectively,whereas that for Type IV storms were 30.0 h,1.4 mmh,and 8.6 mmh.