干旱指标及其在新疆阿勒泰地区干旱监测分析中的应用

Drought Index and Its Application in the Analysis on Drought Monitoring in Altai Region,Xinjiang

干旱是限制新疆阿勒泰地区农牧业生产可持续发展最主要的自然灾害之一,研究适合该区的干旱指标,是进行有效干旱监测的基础。采用新疆阿勒泰地区7个气象站1961-2008年4-10月月平均气温、降水量资料,首先通过Thomthwaite方法计算潜在蒸发量确定K干旱指数,然后对R指数、Z指数、K指数3种干旱指标进行了分析,结果表明,在监测诊断干旱轻重程度上,K指数能较客观地反映出干旱程度,R指数和Z指数监测干旱程度较轻。在此基础上,基于K指数建立的阿勒泰地区干旱监测评价的强度指数和面积指数,对该地区近48年来干旱的变化进行了分析,表明该地区干旱灾害主要集中在春夏季节,春夏连旱几率较高,强度较大;该地区干旱灾害具有阶段性特征,近年来干旱发生的频次有增多的趋势,其中秋季干旱相对较为明显。

Drought is one of the uppermost natural disasters that limit the sustainable development of farming and animal husbandry in Altai of XinJiang,and the study of an appropriate drought index is the base to an effective monitoring of drought condition. Using the monthly average temperature and the precipitation data from April to October,1961 to 2008 that observed by seven weather stations of Altai,the drought index K by calculating the potential evaporate quantity through Thomthwaite method is determined firstly,three drought indexes as R index, Z index,K index are then analyzed. Results indicate that R index can objectively reflect the drought level,R index and Z index are less obvious on the monitoring and judgment of drought level. In the light of these,the drought changes of this area in the past 48 years are analyzed according to intensity index and area index of drought monitoring,both based on K index. The results show that drought in this region mainly appears in spring and summer,with a higher probability and greater intensity of continuous drought between spring and summer. Drought disaster in this region shows a stage characteristic,the frequency of drought increased recently,among which the autumn drought is comparatively evident.