The Statistic Analysis on Extreme Air Temperatureof Some Cities in the Middle Yellow River Basin

摘要

The climate change heavily impacts the hydrological cycle and water resources in a basin. The researches on probability distribution of climate variables of Yellow River basin are the fundament to study the change tendency of flow and sediment in the river. This article selected the extreme temperature series from 1984 to 2004 at both Xi' an and Taiyuan station as the analyzing objectives. The minimum temperature is fitted by Weibull distribution; the maximum value is fitted by Gumbel distribution. The coefficients of the two distributions were estimated by the moment method and the least square method. The recurrence time of T — year event of the extreme temperature is analyzed, and the method how to calculate the number of T — year event in a given time is presented in this article. The results of the statistical computation showed that two distributions fitted the data well. The methodology presented in this paper may be used to analyze other hydrological and meteorological variables.