青海省东部农业区作物生长期不同气象干旱指标应用研究

Application research on different drought indices in crop growing period at east agricultural region of Qinghai Province

干旱一直是制约青海东部农业区农牧业生产最主要的气象灾害。利用青海东部12个气象站点近46年(1961-2006年)的气象资料,计算标准化降水指数(SPI)、降水Z指数和相对湿润度指数(M),并对各干旱指标表征的年、春季和夏季的干旱强度和干旱频率与实际干旱事件进行对比,分析其在研究区的适用性,进而分析研究区的干旱变化特征。结果表明:3种干旱指标相比,相对湿润度指数(M)对实际干旱事件的反映更准确,且能反映出不同地区干旱发生频率的差异。选取相对湿润度指数(M)作为区域干旱监测指标,得出时间上区域的春季干旱强度>年干旱强度>夏季干旱强度,夏季的干旱强度有不显著的增大趋势,而年尺度和春季的干旱强度有不显著的减小趋势;空间上,区域干旱频率和干旱强度均表现为南高北低的特征。

Drought has been the main meteorological disasters restricting agricultural and animal husbandry production in the east agricultural region of the Qinghai Province. Using data of 12 meteorological stations in the eastern part of Qinghai Province from 1961 to 2006,this paper first calculated the standardized precipitation index( SPI),precipitation Z index and relative moisture index M,and then compared the annual,spring and summer drought intensities and frequencies with the actual drought events to analyze different drought index's applicability in the research area,and then analyze drought variation characteristics in the study area. Results show that,both the actual drought events and were relative moisture index( M) reflected the difference of drought frequency in different areas more accurately than the other two drought indices. Therefore,choosing relative moisture index( M) was chosen as the regional drought monitoring index,and it is concluded that,the spring drought intensity is greater than the annual drought intensity,the annual drought intensity is greater than the summer drought intensity temporally,and the summer drought intensity has an insignificant increasing trend. However,the annual and spring drought intensities have an insignificant decreasing trend,and spatially,both the drought intensity and the drought frequency increase from north to south.