夏玉米花期高温热害时空分布特征

为了对河南夏玉米花期高温热害的时空分布特征进行定量化评估,利用夏玉米发育期资料和对应时段逐日最高气温资料,分析夏玉米花期高温热害的时空变化规律。结果表明,河南省1970~1999年间夏玉米开花期高温日数变化不大,2000~2009年间高温日数最少,2010年后明显增多。将河南省按照豫东、豫南、豫西、豫北和豫中划分5个区域,以豫南高温日数最多,此后依次为豫东、豫中、豫西和豫北地区。河南省大部分地区夏玉米开花期平均高温日数为4~6日,豫北及豫西部分地区为2~4日,豫南部分地区为6~8日。豫南地区7月20~29日发生5日及以上高温日数的频次最高,为10年2~3次;随着日期的推后,发生5日以上高温的频次逐渐降低;8月9日后,全省大部分地区发生5日及以上高温的10年重现率降至1次以下。

Spatiotemporal Variation of Flowering Stage Heat Damage of Summer Maize

The aim of this paper is to quantify comparative analysis of heat damage during flowering stage of summer maize, and detailed evaluation the spatial and temporal distribution of heat damage during flowering stage of summer maize. Time span of flowering stage was analyzed based on observed growth stages. Temporal and spatial distribution of high temperature during summer maize flowering stage were analyzed based on daily maximum temperature. The result indicated that high temperature days from 1970 to 1999 kept steadily, and high temperature days from 2000 to 2009 were least among the three periods, high temperature days increased obviously since 2010. Then the area of Henan province was divided into five sections:the eastern part of Henan, the southern part of Henan, the western part of Henan, the northern part of Henan and the middle of Henan. While the high temperature days in the southern part of Henan are the most, followed by the eastern part of Henan, the middle of Henan, the western part of Henan and the northern part of Henan. The average high temperature days were 4 to 6 days in most part of Henan province, 2 to 4 days in parts of the northern part and the western part of Henan, and 6 to 8 days in part of the southern part of Henan. The frequency of high temperature days over 5 days was highest in the southern part of Henan with 2 to 3 time per ten years. The frequency of high temperature days over 5 days was declined with the date pushed back. Ten-year recurrence rate of high temperature days over 5 days was below 1 time between 9th august and 18th august in most parts of Henan.