山东省的干旱化特征分析

利用山东省近50多年的农业旱灾灾情资料和降水资料，分析了干旱灾情和致灾因子的变化特征。结果指出：20世纪70年代后期以来，6—9月份西太平洋副高脊线位置偏南，山东省的汛期降水量有明显的减少趋势，导致干旱灾害的受灾面积明显增大。进入90年代以后，与1961—1976年相比，干燥度指数普遍增大，半岛东部及黄河以北地区干燥程度增大得最为明显，半岛东部、鲁东南及鲁南的大部分地区由湿润区演变成了半湿润区，而黄河以北绝大部分地区及鲁中北部、半岛西北部的局部地区则由半湿润区演变成了半干旱地区。造成干燥度变化的主要原因是降水量的变化，其次是积温的变化。

Characteristic analysis of change into drought in Shandong Province

By utilizing the data on agricultural drought disaster and precipitation in past 50 years in Shandong Province, the characteristics of agricultural disaster and variation features of hazard -formative factors are analyzed. The results show that after the later 1970g, the position of subtropical high ridge line in west Pacific is normal by south, the rainfall in flooding season is less than the normal remarkably, and agricultural drought disaster is severe. After the 1990g, dryness index increase especially in east of Shandong Peninsula and north of Yellow River ; east of Shandong Peninsula, most of south-east Shandong and south Shandong are from humid to semi-humid , the areas to the north of Yellow River is from semi-humid to semi-arid than that of the year from 1961 to 1976. The first reason of dryness index variation is the rainfall change, the second is the chang of accumulated temperature.