GIMMS NDVI time series reveal the extent, duration, and intensity of blooming desert events in the hyper-arid Atacama Desert, Northern Chile

The blooming desert, or the explosive development and flowering of ephemeral herbaceous and some woody desert species during years with abnormally high accumulated rainfall, is a spectacular biological phenomenon of the hyper-arid Atacama Desert (northern Chile) attracting botanists, ecologists, geo-scientists, and the general public from all over the world. However, the number of blooming deserts, their geographical distribution and spatio-temporal patterns have not been quantitatively assessed to date. Here, we used NDVI data from the Global Inventory Modeling and Mapping Studies (GIMMS) project to reconstruct the annual land surface phenology (ISP) of the Atacama Desert using a non-parametric statistical approach. From the reconstructed LSP, we detected the blooming deserts as positive NDVI anomalies and assessed three dimensions of the events: their temporal extent, intensity of greening and spatial extent. We identified 13 blooming deserts between 1981 and 2015, of which three (1997-98, 2002-03, and 2011) can be considered major events according to these metrics. The main event occurred in 2011, spanning 180 days between July and December 2011, and spread over 11,136 km2 of Atacama dry plains. Blooming deserts in Atacama have been triggered by the accumulation of precipitation during a period of 2 to 12 months before and during the events. The proposed three-dimensional approach allowed us to characterize different types of blooming deserts: with longer episodes or larger spatial distribution or with different greening intensities. Its flexibility to reconstruct different ISP and detect anomalies makes this method a useful tool to study these rare phenomena in other deserts in the world also.