东北地区玉米干旱时空特征分析

Analysis of spatio-temporal characteristics of drought for maize in Northeast China

利用1961-2007年东北地区124个气象站日气象数据,采用彭曼-蒙特斯方程计算参考蒸散量、作物需水量及玉米水分亏缺指数,按玉米生长的不同发育期确定不同干旱等级玉米水分亏缺干旱指标并计算了干旱频率,并就其时空分布及其年际变化特征进行分析。结果表明：东北地区玉米生长季内干旱呈现明显的季节性和区域性,干旱发生频率较高的时段主要在苗期生长阶段,其次是灌浆成熟期;玉米苗期、拔节期、抽雄开花期、灌浆成熟期轻旱以上干旱频率都呈东北向西南逐渐增加的分布趋势,区域性比较明显;辽宁西部和南部、吉林西部和黑龙江西南部地区干旱发生频率较高,是干旱的主发区,玉米苗期、拔节期、抽雄开花期、灌浆成熟期干旱发生频率分别为60%-96%,30%-58%,20%-40%,30%-52%,从年代际变化看,20世纪60年代到80年代干旱缓和,从90年代初开始干旱呈增加的趋势,90年代中期以后干旱增加趋势明显,特别是2000-2004年维持在一个较高的水平。由此可见,东北地区近十年来干旱呈显著增加的趋势,且干旱在各个发育阶段同时发生。

Based on the observation data of temperature,precipitation,wind,vapor pressure and sunshine hours collected from 124 weather stations during 1961～2007 and the Penman-Montieth equition,the potential evapotranspiration（ET0） and Miaze water requirement（ETC） were calculated,the maize crop water deficit index（CWDI） of different classes of drought were detemined and the frequencies of different classes of drought in Northeast China were calculated.The results showed that there were significant seasonal and spatial distribution characteristics.Drought occurred in high frequency at the stage of seedling,secondly,filling-maturity stage,and the occurring frequency of slight drought or above in various growth stages of maize showed an increasing trend from northeast to southwest.In the major dry areas,the drought occurring frequency in seedling,jointing-booting,tasseling-silking and filling-maturity stages was 60%～96%,30%～58%,20%～40% and 30%～52%.For inter-decade change characteristics,drought fluctuation was moderate in the 1960～1980 s, while it turned an increasing trend since the early 1990 s,especially after the mid 1990 s,and it maintained at a high level in 2000～2004.Therefore,drought increased significantly in Northeast China in the recent 10 years and it occurred in each stage of maize development.