陕西关中西部作物生长季近70年旱涝指数分析——以杨陵为例

An analysis of index of dryness/wetness for growth season during past 70 years in western Guanzhong -- Taking Yangling as a case

用 Bhalme和 Mooley提出的旱涝指数计算方法 ,计算分析了作物生长季 ( 3月～ 1 0月 )杨陵近 70年的旱涝指数。结果表明 ,作物生长季各月不同等级的干旱出现频率远大于涝等级的出现频率 ,其中重旱以 4月～ 5月和 9月～ 1 0月出现频率 >5 % ,中旱以 3月～ 4月 ,6月和 8月出现频率 >1 0 % ;1 930 s～ 1 940 s和 1 970 s～ 1 990 s旱多于涝 ,中旱～重旱出现频率分别比中涝～重涝高 9.9%～ 1 2 .1 %和 1 1 .2 %～ 30 .0 % ;1 95 0 s～ 1 960 s大旱大涝并存 ,涝略多于旱 ,中涝～重涝出现频率比中旱～重旱高 3.8%～ 7.5 %。旱涝指数在 1 95 2年和1

The index of dryness/wetness and the grade of dryness/wetness based on method of Bhalme and Mooley are calculated for growth season (March to October)during past 70 years at Yangling. The result shows that the frequency of various grades of dryness is bigger than that of wetness in several months during growth season. The frequency of serious dryness is >5% from April to May and September to October, while the frequency of middle dryness is >10% from March and April and June and August. The frequency of middle serious dryness is 9.9%~12.1% and 11.2%~30.0% higher than that of middle serious wetness during 1930s^1940s and 1970s^1990s respectively, while the frequency of middle serious wetness is 3.5%~7.5% higher than that of middle serious dryness during 1950s^1960s. The index series of dryness/wetness has a phenomenon of climatic jump in 1952 and 1976.