Continuous low temperature, heavy snow and freezing emerged in Central China in mid-November 2009. The situation and impact of snow was analyzed and evaluated based on MODIS date and NDSI. The results showed that the curve of snow area changed as a single peak, the maximum value was on November 15th. The key snow area was in Shanxi province with 62. 89 × 104km2, following Shaanxi ,Henan and Hebei province with 40. 10 × 104km2, 37. 62 × 104km2, 37.58 × 104 km2 respectively. No more than 10. 5 × 104 km2 in Shandong, Hubei and Beijing. The rapeseed has been negative impact due to seeding stage. However, the winter wheat could get more moisture during over-wintering stage.%2009年11月中旬,中国中部地区出现了大范围持续低温、雨雪、冰冻天气气候事件,造成了积雪灾害.本文利用连续多天的MODIS遥感数据,通过计算归一化差分积雪指数(NDSI,Normalized Difference Snow Index)分析了北京、河南、河北、湖北、山东、山西、陕西7个地区的积雪状况,对积雪发生的时空特征进行了动态监测,并对监测省份农业受到的影响进行评估.结果表明:监测区整个降雪过程积雪面积呈单峰型变化,11月15日积雪面积最大,15日以后积雪面积开始减少,24日监测区积雪基本融化;山西省为本次降雪过程的核心区域,累计积雪总面积为62.89×10<'4>km<'2>,陕西、河南、河北省次之,分别为40.10×10<'4>km<'2>、37.62×10<'4>km<'2>、37.58×10<'4>km<'2>,山东、湖北、北京受积雪覆盖影响较小,积雪总面积分别为10.42×10<'4>km<'2>、8.52×110<'4>km<'2>、0.42×10<'4>km<'2>;监测期间油菜作物均处于出苗期,持续积雪覆盖会对其产量造成一定影响.已进入越冬期的冬小麦,稳定的积雪覆盖会产生积雪融水,进而土壤墒情得到改善,有利于作物来年生长.尚未进入越冬期的冬小麦抗寒能力较差,持续低温积雪对其生长及产量造成不良影响.
展开▼
