基于作物水分亏缺指数的吉林省玉米不同生育时段干旱特征分析

Analysis of Characteristic on Drought in Different Developmental Times of Maize Based on Crop Water Deficit Index in Jilin Province

利用吉林省1961-2015年46个气象站的逐日气象数据,结合Penman-Monteith方程,计算玉米生育期逐旬需水量(Et_c)、降水量以及作物水分亏缺指数(CWDI),根据干旱等级指标计算逐旬不同等级干旱频率、平均干旱强度以及干旱风险指数,并分析其空间分布和时间变化特征。结果表明:从玉米生长季水分供需状况看,西部地区整个玉米生长季水分亏缺最严重,玉米易遭受干旱威胁,中部发生干旱的威胁次于西部地区,东部发生干旱的威胁最小。西部地区干旱发生频率最高,其次是中部,东部地区干旱发生频率最低,平均干旱强度和干旱风险指数与此有相同的分布特征。各等级干旱基本上是在玉米生长的前期和后期发生频率较高,而在玉米生长的关键期,发生频率相对较小。除个别情况,各时段基本是轻旱发生频率最高,其次是中旱,而重旱发生频率较低,特旱发生频率最低。代表站各时段水分亏缺指数年际变化基本是中前期呈减少趋势,中后期呈增加趋势。不同时段各等级风险区空间分布也存在差异。

Based on daily meteorological data from1961 to 2015 of 46 meteorological stations,and Penman-Montieth equation,the water requirement,precipitation and crop water deficit index(CWDI)in every ten days of Maize growth stages were calculated.According to the drought level indicators,frequency of different grade drought,average intensity of drought,and risk index of drought were calculated in each ten days and their spatial distribution and temporal variation were analyzed.The result showed that,in terms of water supply and demand in maize growth season,the water deficit is the most serious in the West in the whole growth season,and it is susceptible to drought threatened,while the threat of drought in the Middle is inferior to the west,and the threat of drought in the East is the least.The west has the highest drought occurrence frequency,followed by the Middle,and the East has the lowest drought frequency.Average intensity of drought,and risk index of drought have the nearly same distribution characteristics.Basically,frequency of each grade drought is high in the early and late stages,while it is low in the critical period of maize.Basically,with few exceptions,the occurrence frequency of the light drought is the highest,next is the moderate drought,while the occurrence frequency of the severe drought is low and the excessive drought is the lowest in each stage.The inter-annual variability of water deficit index of representative stations in each time periods is that,the early-middle stages have decreasing trend while the middle-late stages have increasing trend.There are also differences in the spatial distribution of each level risk area in different time periods.