Global trend analysis of the MODIS drought severity index

Abstract

Abstract. Recently, Mu et al. (2013) have compiled an open access data base of a remotely sensed global drought severity index (DSI) based on MODIS satellite measurements covering a continuous period of 12 years. The highest spatial resolution is 0.05° × 0.05° in the geographic band between 60° S and 80° N latitudes (more than 4.9 million locations over land). Here we present a global trend analysis of these satellite based DSI time series in order to identify geographic areas where either positive or negative trends are statistically significant. Since a DSI value conveys local characterisation at a given site, we argue that usual field significance tests cannot provide more information about the observations than the presented analysis. We are fully aware of the fact that 12 years are too short for establishing any link to global climate change, however a series of severe droughts or inland inundation on a scale of a decade might have devastating consequences for affected human communities.