An index to quantifying the impacts of agricultural drought and its application in China

As one of the major weather-driven natural disasters, droughts exhibit as the most frequent and widespread natural disasters in China. It is reported that the agriculture losses show continuously grown by following the increasingly severe droughts for the whole country. In order to investigate the impacts of drought on agricultural, we rechecked the functional relationship between the crop yield and climatic variables. Based on the meta-analysis from previous literature, we found a more stable statistical relationship between the yield and the precipitation and evapotranspiration. These results introduce a new drought index, indicated as Crop Water-Related Index for Drought (CWRID), which can be used as a reference index to approximate the drought impact on the loss of yield. Based on the climatic data in China during 1982-2015, several other drought indices (SPI, SPEI, CI, and SEDI) were compared with CWRID to identify the most appropriate agricultural drought index. The data of historical drought damaged area and drought damaged crop yield reduction were used to validate the performances of different indices. The CWRID reasonably predicted the drought damaged area as well as the drought damaged yield reduction during the past 30 years in China. As a contrast, the SEDI is proved to be no suit for quantifying drought. Also, the calculated values are stored in the dataset and can be shared with researchers by request. As a simple index, results indicated that CWRID can be used to quantify the impacts of drought on agricultural as it can reflect the variation of crop yields.