Coupled vegetation‐precipitation variability observed from satellite and climate records

Abstract

Variability in precipitation regimes at seasonal and longer time scales strongly influences ecosystem dynamics in arid and semi‐arid regions. In this paper, we use time series of global precipitation and satellite normalized difference vegetation index (NDVI) data to analyze joint spatial and temporal variability between terrestrial ecosystems and precipitation regimes. Accumulated monthly rainfall anomalies are quantified using a standardized precipitation index (SPI), which provides a better measure of ecologically significant precipitation excess or deficit at growing season time scales relative to monthly precipitation data. Results from canonical correlation analysis reveal geographically extensive patterns of joint NDVI‐SPI variability suggestive of strong climate‐biosphere coupling. Further, leading modes of covariability are shown to be related to large‐scale ocean‐atmosphere circulation anomalies. These results illustrate the global extent and sensitivity of ecosystems susceptible to climate change‐induced perturbations in precipitation regimes.