基于Palmer指数的朝阳地区1952-2015年干旱演变特征研究

利用辽宁省朝阳市6个地区的气象站1952-2015年期间64年的逐日降水量、气温等气象数据计算其Palmer干旱指数,并应用小波分解对PDSI指数进行多分辨率分析,从而探究了该地区干旱发生等级、频次、覆盖范围、周期、突变等时间演变特性及发生规律,将为农业生产、抗灾预警、救灾措施制定等工作提供理论依据.研究结果表明,朝阳地区年干旱变化呈明显的5年小周期和10年大周期重复,夏季和秋季发生多次干旱突变,1980s突变较为明显;秋季的干旱情况最为严重、夏季的干旱次之、冬季和春季的干旱程度较轻;年、春、夏、秋、冬干旱发生频次分别为5.72、1.3、1.59、1.56、1.41个月;干旱覆盖范围分别为82.6%、38.0%、48.2%、47.9%和37.0%.

A Study on Drought Temporal Variation Characteristic of Chao Yang District in 1952-2015 Based on PDSI

The Palmer drought severity index of Chao Yang district is calculated based on the daily precipitation and temperature data of six monitoring stations from 1952 to 2015 and decomposed by wavelet for multi resolution analysis.The drought temporal variation characteristic indexes,such as grades,frequency,coverage,cycle and mutation are investigated.The results show that the inter annual and seasonal drought present increasing trends in Chaoyang district;autumn drought is the most serious,summer drought is the second,and drought in winter and spring is lighter;the annual and four seasonal drought occurrence frequency is 5.72,1.3,1.59,1.56,and 1.41 months,respectively,and the corresponding draught coverage is 82.6%,38.0%,48.2%,47.9% and 37.0%,respectively;drought mutation is very familiar in summer and autumn,especially in 1980s and drought appears with several cycles nesting each other.