Comprehensive drought index as an indicator for use in drought monitoring integrating multi-source remote sensing data: a case study covering the Sichuan-Chongqing region

Numerous meteorological drought-monitoring indices and remote-sensing-based spatial drought monitoring indices have been developed and applied to monitor drought in different ways. However, individual indices have obvious deficiencies in terms of their responses to drought, and they do not comprehensively reflect the available information on drought. To overcome issues with the data themselves and improve drought monitoring techniques, we use a comprehensive drought index (CDI) derived from the vegetation condition index, the temperature condition index, and the precipitation condition index to monitor meteorological or agricultural drought for the Sichuan-Chongqing region. To assess CDI performance, monthly CDI values for Sichuan-Chongqing region were used to analyse the spatial and temporal variations of the 2006 drought. The results indicated that all aspects of the drought were monitored, and the results were in agreement with related research. Meanwhile, an extreme drought was accurately explored using the CDI in the Sichuan-Chongqing region from 2000 to 2011. Finally, a validation was performed, and the results show that the CDI is closely related with the standardized precipitation index calculated using a 3-month time scale (SPI3), as well as variations in crop yield and drought-affected crop area. These results provide further evidence that the CDI is an indicator that can be used in integrated drought monitoring and that it can simultaneously reflect meteorological and agricultural drought information.