Abstract:

Based on the standardized precipitation evapotranspiration index (SPEI), the temporal-spatial distribution and variation characteristic of the  light, moderate and heavy drought frequency in summer maize growing season in North China Plain were studied. The results show that the drought frequency was more than 50.0% in summer maize growing season, especially light drought occurred frequently. In southeastern part of Henan, and the middle and northern part of Hebei, drought frequency was higher. The higher light drought frequency occurred in June and October, while moderate drought mainly occurred in August and October, and heavy drought events were concentrated in June and July. The drought showed aggravated trend from 1961 to 2015, especially in October. Compared with the period 1961-1980, the drought frequency percent in the study area has increased by 37.3% in the last 15 years. The drought frequency in north-central Hebei, Beijing, Tianjin and northwestern part of Henan was more than 60.0%. As drought in different months had different effects on the growth of summer maize, the prediction of drought events in July and August needed to be strengthened so that we could make timely and effective measures for disaster prevention and mitigation.

摘要：

基于标准化降水蒸散指数（SPEI），从不同时间尺度对华北平原夏玉米生长季1961—2015年不同等级干旱发生频率、时空分布和变化特征进行了研究。结果表明，华北平原夏玉米生长季干旱频发，频率超过50.0%，主要以轻旱为主，河南东南部和河北中北部地区干旱频率高于其他地区，6月和10月轻旱频率相对较高，8—10月更容易发生中旱，重旱主要出现在6月和7月。近55 a年华北平原夏玉米生长季干旱不断增加，10月干旱频率增加趋势最显著。与1961—1980年相比，研究区近15 a干旱发生频率增加百分率为37.3%，其中河北中北部、北京、天津和河南西北部干旱发生频率在60.0%以上。不同月份的干旱对夏玉米生长影响不同，需要加强对8月和9月干旱事件的预报，以便及时采取防灾减灾措施。

关键词: 华北平原, 夏玉米, SPEI, 干旱