基于信息扩散和模糊评价方法的四川盆地气候干旱综合评价

利用1961~2005年历史气象资料,以受旱天数、湿润度指数、标准化降水指数、温度距平、日照距平百分率等5个要素作为干旱评价指标,应用信息扩散方法建立了各单个评价指标的春、夏、伏旱旱情等级划分标准,采用模糊综合评价方法对1961~2006年四川盆地气候干旱进行评价,并给出了各市干旱出现的频率。结果表明:2006年四川盆地发生了严重的春旱、夏旱和特别严重的伏旱,盆区17个市均有伏旱发生,其中有13个市伏旱特别严重;伏旱期少雨天气平均为30年一遇,高温天气平均为60年一遇,约29%的台站的少雨和90%的台站的高温为50年以上一遇;春、夏旱主要出现在盆地西北部和盆地南部,约2.5年出现一次,伏旱则主要出现在盆地东部,约2年出现一次。

The Drought Assessment of Sichuan Basin Based on Information Diffusion and the Fuzzy Comprehensive Evaluation Method

According to meteorological datasets from 1961 to 2005,we selected drought days,relative wetness index,standard precipitation index, temperature anomaly and percentage of sunlight anomaly as evaluation indices of drought.Based on the method of information diffusion,level standards of agricultural drought that correspond to different evaluation indices were established.Then we assessed drought in Sichuan Basin during 1961-2006 with the fuzzy comprehensive evaluation method,and gave the drought occurrences frequency of each city.The results showed that severe spring drought,severe summer drought and extremely severe late-summer drought occurred in Sichuan Basin in 2006.Late-summer drought occurred in all the 17 cities,of which 13 cities witnessed extremely severe late-summer drought in the Basin.On average,the sparse precipitation weather occurred about once every 30 years in late summer.High-temperature occurred once every 60 years.About 29%of stations encountered the shortage of precipitation,and 90% of stations encountered high temperature,which occurred once over 50 years.Spring drought and summer drought mostly occurred in northwest and south of Sichuan Basin,about once per 2.5 years,late-summer drought mostly occurred in east of Sichuan Basin,about once per 2 years.