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干旱是影响社会发展和农业生产的重要因素之一。本文基于EOS/MODIS卫星遥感资料,选取江西省2001-2006年的NDVI时间序列数据,分析了NDVI对干旱的响应规律。计算了NDVI与气温、降水之间的关系。并提取植被状态指数(VCI),分析VCI与气温距平、降水距平的空间分布规律。结果表明:2003年江西夏季旱灾以高温少雨天气为主。这一时期的NDVI数值明显低于其他年份同一时期的NDVI值。气温温度越高,NDVI值越大;日照时数时间越长,NDVI值越大;降水量越高,NDVI值越大;降水距平百分率越高,VCI值越高;平均温度距平越小,VCI值越高。说明气候因素对NDVI指数和VCI指数有很大影响。研究表明,基于MODIS的植被指数可以反映旱灾的时空分布规律。
Drought is one of the important factors affecting social development and agricultural production. Based on the EOS / MODIS satellite remote sensing data, this paper selects the NDVI time series data of Jiangxi Province from 2001 to 2006, and analyzes the response of NDVI to drought. The relationship between NDVI and temperature and precipitation is calculated. The vegetation status index (VCI) was extracted and the spatial distribution of VCI, air temperature anomaly and precipitation anomaly were analyzed. The results show that in 2003, the summer drought in Jiangxi province was dominated by high temperature and a few rainy days. The NDVI values of this period are obviously lower than the NDVI values of the same period of other years. The higher the temperature is, the higher the NDVI is; the longer the sunshine duration is, the larger the NDVI is; the higher the precipitation is, the larger the NDVI is; the higher the precipitation anomaly is, the higher the VCI is and the lower the average temperature anomaly is , VCI value is higher. This shows that climatic factors have great influence on NDVI and VCI. The results show that the vegetation index based on MODIS can reflect the spatial and temporal distribution of drought.