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The frequency of precipitation days in the Yangtze River basin

YIJIN WU¹, STEFAN BECKER², LORENZ KING³, HSIANG-TE KUNG⁴, TONG JIANG⁵, HEIKE HARTMANN³ & WENJING ZHU⁶

1 School of Urban And Environmental Sciences, Central China Normal University, Wuhan 430079, China

wuyijin@public.wh.hb.cn

2 Department of Geography, University of Wisconsin Oshkosh, 800 Algoma Boulevard, Oshkosh, Wisconsin 54901, USA

3 Geographisches Institut, Justus-Liebig-University, Giessen, Germany

4 Department of Earth Sciences, The University of Memphis, Memphis, Tennessee 38152, USA

5 Nanjing Institute of Geography and Limnology, CAS, Nanjing 210008, China

6 School of Earth Sciences, China University of Geosciences, Wuhan 430074, China

Abstract This paper explores the frequency of precipitation days to better understand flood potential by using different percentiles in the Yangtze River basins from 1950 to 2000. The positive (increasing) trends of the precipitation days at the 75th and the 95th percentile are analysed on both yearly and decadal scales. Some interesting facts have been revealed through this study. It is observed that the precipitation days at the 75th percentile increase more than that of the 95th percentile in the basin. This explains that the yearly increasing precipitation is due to excessive rains and not heavy rains. Also, through the trends (positive and negative), the variation of yearly precipitation days can be classified.

Key words frequency; precipitation days; trends; Yangtze River basin

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