基于信息扩散理论分析华北平原夏玉米花期高温热害的风险概率

利用1980−2019年华北平原40个站点的气象数据，将夏玉米花期日最高气温≥35℃持续3d及以上作为高温指标，综合考虑频次和持续时间，制定轻度、中度、重度高温热害等级；利用灾害发生次数和站次比分析夏玉米花期高温热害的变化规律；基于信息扩散理论评估高温热害风险概率，为科学应对夏玉米花期高温热害，保障夏玉米的高产稳产提供依据。结果表明：（1）2010−2019年是华北平原夏玉米受花期高温热害影响加重的阶段，呈现连年发生、范围明显扩大的特征，河南省表现明显。（2）夏玉米花期高温热害高风险区主要为山东西部和河南省，山东西部以轻度热害为主，风险概率在10a一遇以上（≥10%）。河南省受灾范围广、频次高、程度重，重度高温热害的风险概率在10a一遇以上（≥10%）的面积占比为66%，5a一遇以上（≥20%）的面积占比为18%。

Risk Probability of Heat Injury during Summer Maize Flowering Period in North China Plain Based on Information Diffusion Theory

Maize is the most important grain crop in China, and North China Plain is the main production area of summer maize. The maize production has been threatened by the rapid increase of extreme temperature events in the context of climate change. The characteristics and risk probability of heat injury during the flowering period of summer maize were analyzed, based on the meteorological data from 40 weather stations in North China Plain from 1980 to 2019, in order to deal scientifically with heat injury and ensure the high and stable yield of summer maize. The daily maximum temperature during summer maize flowering period with more than 35℃ for more than 3 days was taken as the index of heat injury, and the grades of heat injury would be divided into slight, moderate and server levels in terms of the occurrence time and duration of heat injury. The characteristics of heat injury during the flowering period of summer maize were analyzed by the occurrence times and the stations ratio of heat injury occurrence in the study area. Moreover, the risk probability of heat injury was evaluated using the theory of information diffusion. The results indicated that: (1) the period of 2010−2019 had more serious effects of heat injury during the flowering period, which showed the characteristics of successive occurrence and spatial expansion of heat injury. The most serious heat injury happened in Henan province, which the station ratio of heat injury occurrence reached 60.7% during 2010−2019, and increased by 51.4% compared with 2000−2009. The climate tendency rate of heat injury occurrence times in Zhengzhou, Gushi and Nanyang regions reached about 0.2 times·(10y) −1 (P<0.01); (2) The high-risk areas of heat injury during the flowering period of summer maize happened in Henan province and western Shandong. A wide range, high frequency and severe severity of heat injury took place in Henan province, and the proportions of areas with severe heat injury with more than 10% and more than 5% were 66% and 18%, respectively. The slight heat injury was the main meteorological disaster in the west of Shandong province, and its risk probability was more than 10%. The risk of heat injury in the Beijing-Tianjian-Hebei area and eastern Shandong province was lower compared with Henan province, and its risk of slight and moderate heat injury was less than 5%.