Construction and precision evaluation of comprehensive drought index based on meteorological and Remote sensing vegetation information

Objectives: Accurate monitoring of drought is of great practical significance for agricultural production around the world, and it is beneficial to the sustainable development of an economy. As a vital tool to measure the degree of regional drought, the construction of a comprehensive drought index with high monitoring accuracy is one of the research hotspots nowadays. Methods: This paper constructed a new comprehensive drought index （ MADI, Meteorology-Agriculture Drought Index）combined with the NDVI and monthly mean precipitation based on the Gaussian Copula Function. The superiority of MADI in capturing drought events was confirmed by statistical comparison with SPI and VCI at monthly scale and by testing in historical events. Results: The result of the research shows that: (1) MADI has high consistency with traditional drought index SPI and VCI. The months with a consistent characterization of MADI and SPI accounted for 62.24% of the total months. And the figure is 83.47% taking into account the MADI and VCI. And the months that MADI with either consistent characterization of SPI or VCI to characterize drought accounted for 97.83% of the total months.(2) MADI has high sensitive to capturing drought. In the months when MADI is consistent with SPI and VCI characterization, the absolute value of MADI was greater than that of SPI or VCI in more than 60% of the months, which means that the MADI is clearer in drought characterization. (3) MADI is more accurate in contrast to the record of historical drought events in the meteorologic yearbook. MADI successfully capture two major drought events from January to April 2012 and August to October 2007. However, the SPI and VCI fail to characterize the above events. Conclusions: Therefore, the MADI can serve as a helpful complement to SPI and VCI since it can provide an auxiliary decision for the accurate judgment of drought disasters in the Yangtze River Basin.