Spatial-temproal Features of Annual Extremes of Heavy Precipitation Processes in the Yangtze River Delta

Abstract:

The annual extremes characteristics of daily and a continuous process rainfall are analyzed by REOF and statistical models using the daily precipitation data of 80 stations in the Yangtze River Delta.The results show that the extreme precipitation in the Yangtze River Delta mainly belongs to the following patterns:South-east difference pattern of annual extremes of daily rainfall;North-south difference pattern of annual extremes of a continuous process rainfall.The four kinds of statistical models (Gumbel,Lognormal,Weibull,and Person Ⅲ) were used to fit the annual extremes series of daily and a continuous process rainfall.Test results have showed that the Weibull distribution is more suitable to the daily rainfall,and the lognormal distribution fits the continuous process rainfall.The spatial distribution of the extremes of a continuous process rainfall is relatively concentrated,and its spatial-temporal variabilities are smaller than those of the extremes of daily rainfall.

Key words:a continuous process rainfall;REOF;Weibull distribution