基于SPEI指数的河北省南部夏玉米生长季干旱特征分析

利用河北省南部8个气象站点1962—2018年的逐月气温、降水量数据,采用标准化降水蒸散指数(SPEI),通过小波分析、Mann-Kendall检验等方法,分析了河北省南部夏玉米生长季(6—9月)干旱变化特征以期为干旱灾害的监测、预报预警及防御提供理论依据。结果表明:夏玉米苗期干旱发生频率为31.5%,1966年后苗期气候呈湿润化趋势,在1968和2009年附近可能发生了气候湿润化的突变,整个分析期(1962—2018年)干湿变化包含13～18a、5～8a周期振荡;夏玉米穗期干旱发生频率为40.3%,2006年后穗期气候呈持续干旱化趋势,在1980和1997年附近可能发生了气候干旱化的突变,整个分析期干湿变化包含15～22a、6～10a周期振荡;夏玉米花粒期干旱发生频率为29.8%,1989年后花粒期气候呈持续干旱化趋势,可能在1992和2002年附近发生了气候干旱化的突变;夏玉米生长季干旱发生频率约为30%,生长季气候总体呈干旱化趋势,特别是1997年后持续干旱化,可能在1996年附近发生了气候干旱化的突变。

SPEI Based Characteristic Analysis of Summer Corn Drought in Growing Season in Southern Hebei Province

Based on the observation data of 8 meteorological stations in the southern Hebei Province from 1962 to 2018, the characteristics and trends of climate change in summer maize growing season (June to September) are analyzed by the regression analysis, wavelet analysis and Mann Kendall test. The frequency of drought in the seedling stage of summer maize was 31.5%. After 1966, the climate in the seedling stage showed a humidification trend. A sudden change in climate humidification occurred around 1968 and 2009. The dry wet changes during the entire analysis period (1962 to 2018) contained the periodic oscillations of 13 to 18 years and 5 to 8 years. The frequency of drought at the ear stage of summer corn was 40.3%, and the climate at the ear stage after 2006 showed a continuous aridity trend. A sudden change in climate aridification occurred around 1980 and 1997. The dry wet changes in the entire analysis period contained the periodic oscillations of 15 to 22 years and 6 to 10 years. The frequency of drought during the flower and grain period of summer maize was 29.8%. After 1989, the climate during the flower and grain period showed a continuous aridification trend. It is possible that a sudden change of climate aridity occurred in 1992 and 2002. The frequency of drought in the summer corn growing season is about 30%. The climate in the growing season showed a trend of aridification, especially after 1997, and there experienced abrupt climate aridification around 1996. The above results are expected to provide a theoretical basis for drought disaster monitoring, prediction, early warning and prevention.