鄂北岗地近54 年来干湿指数变化

选取鄂北岗地及其附近8个气象站点1960年-2013年逐日的气象观测数据,采用FAO推荐的PenmanMontecito模型计算该地区参考作物蒸散量和干湿指数,在此基础上利用Mann-Kendall突变检验、Morlet小波分析等方法分析了干湿指数的变化趋势和总体特征。结果显示:1960年-2013年鄂北岗地干湿指数呈波动上升趋势,其变化速率为0.038/(10a),干湿状况有所改善;夏季干湿指数最大,春秋次之,冬季干湿指数最小;1980年-1981年期间,干湿指数发生了一次由低到高的突变;干湿指数变化过程主要存在3~6a、8~15a和17~25a等3类尺度的周期变化规律,而13a左右的周期变化是干湿变化的主周期;干湿指数与相对湿度和降水量成正相关,与气温、风速、日照时间成负相关,而降水量是导致干湿指数变化的主导因素。

Variation tendency of dry2wet index in Hillock Area of northern Hubei in the recent 54 years

Based on the daily meteor olog ical data of eig ht w eather stat ions in H illock Ar ea o f nor thern H ubei fr om 1960 to 2013,the v alues of refer ence cro p evapot ranspiratio n and dr y2w et index w ere calculated using t he Penman2Montecito equatio n r ecom2mended by the FAO, and the v ariat ion tendency and g ener al char act eristics o f dry2wet index w ere analyzed by the methods ofMann2Kendall test and Morlet wavelets analysis. The r esults indicated that ( 1) the dry2wet index has incr eased slow ly with a rate of01 038/ 10a from 1960 to 2013, and the dry2w et condition has been improved to some extent; ( 2) the dry2wet index is the highest in sum2mer, fo llowed by spring and autumn, and the low est in winter; ( 3) the dry2wet index has an abrupt chang e from 1980 to 1981; ( 4) thedry2w et index has three periodicities of 3~ 6 years, 8~ 15 years, and 17~ 25 years, and the primary perio dicity is 13 year s; and ( 5) thedr y2w et index has posit ive cor relation w ith relativ e humidity and precipitat ion, and negative cor relation w ith t emperat ur e, w indspeed, and sunshine time, and pr ecipitation is the dominant fact or t o cause the var iatio n o f dr y2w et index .