河南省冬小麦晚霜冻害风险区划

基于河南省冬小麦遥感种植面积数据、DEM数据和111个气象站1971-2010年逐日最低气温资料,采用基于GIS的逐日最低气温空间插值技术,根据冬小麦晚霜冻灾度指标及其等级划分标准,计算各空间单元轻霜冻、中霜冻和重霜冻日数,综合考虑霜冻害日数和冬小麦实际种植面积比例因素,构建冬小麦晚霜冻害风险评价指数,分析河南省冬小麦不同等级晚霜冻害日数及其风险的区域特征.结果表明:河南省冬小麦轻霜冻日数高值区主要分布在河南省北部、东部和西部丘陵山区,中霜冻和重霜冻高值区以分布在西部丘陵山区为主,霜冻日数最大值分别为67 d、48 d和120 d；轻霜冻风险较高的区域主要分布在河南省除郑州地区以外的驻马店和南阳盆地以北地区,中霜冻主要分布在东部和西部丘陵山区,重霜冻主要分布在河南省西部丘陵地区,风险指数最大值分别为28％、18％和17％.总体上看,河南省冬小麦晚霜冻害日数和风险空间分布特征明显；轻霜冻日数及其风险的覆盖面积最大,其次为中霜冻,重霜冻最小；河南省的东部、北部和西部丘陵山区为晚霜冻害的主要防御区域,各级霜冻之间以防御轻霜冻为主.

Risk Regionalization of Winter Wheat Late Freezing Injury in Henan Province

Late frost injury of winter wheat that occurs after jointing stage is one of the dominating agrometeorological disasters in Henan province.Frost damage reduces winter wheat yield and threatens the food security.More attentions need to be paid to the spatial distribution of frost injury risk for both scientists and decision-makers who concern about winter wheat production in this area.Based on the data of winter wheat growing area,Digital Elevation Model(DEM) and daily minimum temperature from 111 meteorological stations in the period between 1971 and 2010,the days of mild frost,moderate frost and severe frost are calculated according to the frost injury disaster indices value derived from the minimum temperature after jointing stage and the days after jointing stage and the criteria of frost disaster grades by use of daily minimum temperature interpolation method.The risk assessment index was represented of the frost days and the actual winter wheat growing area percentage.The spatial distribution characteristics of frost injury disaster days and its risk were analyzed.The results showed as follows.During 1971-2010,more days of mild frost were mainly distributed in northern regions,eastern regions and some western hilly and mountainous regions.While more days of moderate and severe frost in western hilly and mountainous regions,and the maximum days of frost was 67 d,48 d and 120 d,respectively.The north of Zhumadian region and Nanyang basin except Zhengzhou region had a higher risk of mild frost disaster,the northern part and western hilly and mountainous regions had a higher risk of moderate frost disaster,and western hilly and mountainous region were more vulnerable to the severe frost disaster.The risk indexes of mild,moderate and severe frost disaster were 28%,18% and 17%,respectively.For the spatial distribution of late frost injury disaster days and risk,the effected area for mild frost was the largest,followed by moderate frost,and severe frost.The eastern,northern and western parts in Henan Province were mainly winter wheat late freezing injury prevention regions.Among the three levels,the mild frost damage should be paid more concentration.