冬小麦干旱的下垫面孕灾环境研究——以淮河流域为例

基于1961—2019年淮河流域140个气象站点的日尺度降水数据和2000—2016年的月尺度的地表温度(LST)、归一化植被指数(NDVI)数据,利用表征气象干旱的标准化降水指数(SPI)挑选确定冬小麦不同生长期的典型干旱年份;利用表征农业干旱温度植被干旱指数(TVDI),借助Landsat-8数据提取淮河流域冬小麦...

Study on the Hazard-formative Environment on Underlying Surface of Winter Wheat Drought-A Case Study of Huaihe River Basin, China

Based on the daily scale precipitation data of 140 meteorological stations from 1961 to 2019, monthly scale Land Surface Temperature (LST) and Normalized Difference Vegetation Index (NDVI) from 2000 to 2016, the Huaihe River Basin was taken as the research area. The meteorological drought was characterized by Standardized Precipitation Index (SPI), the typical dry years were determined, according to the SPI. And the agricultural drought was characterized by Temperature Vegetation Drought Index (TVDI). Landsat 8 data was used to extract winter wheat planting area in the Huaihe River Basin, and the further in-depth analysis was made on the correlation and influence between the underlying surface hazard-formative environmental conditions, such as elevation, slope, river, soil type, soil relative humidity and shallow groundwater depth, and winter wheat drought, to provide theoretical basis and technical support for the study of winter wheat drought disaster prevention and mitigation. The results showed that:(1) From 1961 to 2019, the precipitation changing trend in different growth periods of winter wheat was not obvious, and the precipitation in pre-winter growth period and filling and mature period showed a slightly rising trend. The upward and downward trends of all meteorological stations were not significant. According to SPI, the typical dry year in the pre-winter growth period was 2010, the over-wintering period was 2011, the regreening and heading period was 2006, and the filling and mature period was 2001. (2) By comparing the proportion of meteorological drought and agricultural drought above mild drought and the spatial distribution, the degree of agricultural drought in the Huaihe River Basin was generally greater than the meteorological drought, and their spatial distributions were consistent overall, but there were some regional inconsistencies. It was necessary to further analyze the impact of underlying surface hazard-formative environment on agricultural drought. (3) Winter wheat drought was highly correlated with river, surface soil relative humidity and shallow groundwater depth, but less correlated with elevation, slope and soil type. Winter wheat agricultural drought in the Huaihe River Basin was prone to occur in areas with relatively high elevation, steep slope, semi - hydrogenous soil type, distances from rivers, low surface soil relative humidity and shallow groundwater burial depth of more than 1 m. The degree of drought increased from coastal to inland and was higher in the south and lower in the north, so it was necessary to strengthen disaster prevention and drought resistance in such areas and increase artificial irrigation facilities.