辽西北地区干旱时空变化特征分析

利用辽西北地区14个气象站与水文站1971年-2010年的基础数据,得到降水量距平值、连续无雨日数、河道来水量距平值和相对湿润度,并以这四项指标为基础,利用可变模糊评价法得到辽西北地区综合干旱级别特征值,再结合线性倾向估计法、Mann-Kendall趋势检验与反距离权重法对辽西北地区的气象、水文综合干旱时空分布特征进行分析。结果表明:辽西北整体旱情呈显著加重趋势,1971年-1980年以轻度干旱为主,旱情较严重的时期为20世纪80年代后,1981年-1990年干旱程度最为严重,1980年-2010年是重度干旱高发期,但特大干旱少有发生;辽西北东北部和西南部地区旱情较为严重,且随时间变化呈现出加重趋势,而中部地区干旱较轻,因此抗旱减灾的重点应集中在该区的东北部和西南部地区。

Spatial and temporal variation characteristics of drought in northwestern Liaoning Province

Based on the basic data of 1971-2010 at 14 meteorological stations in northwestern Liaoning province, this paper selected four indexes (the precipitation anomaly, number of consecutive days without rain, river runoff anomaly, and relative humidity), and obtained the comprehensive drought level characteristic value of northwestern Liaoning province using the variable fuzzy evaluation method. Then it used the linear trend estimation method and Mann-Kendall test method to analyze the trend of drought and used the IDW method to analyze the spatial variation characteristics of comprehensive drought. The results show that the drought is growing significantly more serious. During 1971-1980, the drought was mostly mild, but was aggravated after the 1980s, and became the most serious during 1981-1990. The period of 1980-2010 witnessed a high incidence of severe droughts but few extremely severe droughts. The drought was more serious and was aggravated with time in the northeast and southwest of northwestern Liaoning province, but was less serious in the central region. Therefore, drought resistance and disaster reduction efforts should be mainly concentrated on the northeast and southwest of the region.