宁夏环香山地区降水特性分析

通过分析中卫环香山地区兴仁气象站1961—2008年48 a降水资料,探讨不同降水年型降水量及其年内分布,得到香山地区降水年际、年内变化规律,为该地区农业发展提供基础理论数据.结果表明,该地区丰水年（P=20%）、平水年（P=50%）和枯水年（P=75%）年降水量分别为309,242,194 mm;该地区降雨量年际变化大,在一个丰、枯周期内,丰水期只有2~3 a,而枯水期则有3~4 a,甚至更长;在48 a降水序列中出现连枯、连丰期的次数相同,但连枯期的历时长,最长可达8 a;降水主要发生在6—9月4个月,其降雨量占全年降水量的72.5%,并与该地区主要栽培作物西瓜的需水高峰期吻合.

Analysis of precipitation characteristic around Xiangshan region in Ningxia

Based on the monthly precipitation data of Xinren station from 1961 to 2008 around Xiangshan region in Zhongwei,basis data was provided for agriculture development of Xiangshan region through the investigation of amount and distribution of annual precipitation in different hydrological model year and the law of precipitation temporal variation inter-annual and among a year.Results showed that the amounts of precipitation were 309 mm,242 mm and 194 mm in wet year（P=20%）,average year（P=50%） and dry year（P=75%） respectively.The inter-annual variation of precipitation was great.The duration of wet period was 2 to 3 years and that of dry period was 3 to 4 years or even longer in a wet-dry circle.The count of occurrences of continuous wet period and continuous dry period was equal,but the duration of continuous dry period was longer than that of continuous wet period and the longest was 8 years.The precipitation was mainly occurred in June,July,August and September in averaged year and the percentage of the four months rainfall to that of a whole year was 72.5%.The precipitation temporal distribution coincided with the water requirement of watermelon.