This article, written by Chris Funk of the US GS, outlines how the Famine Early Warning Systems Network (FEWS NET) uses satellite data and statistical forecasts to provide early warnings of potential droughts in sub-Saharan Africa.

Funk outlines the role of satellite data in FEWS NET at all stages of the crop-growing season — from scenario building before the season to calculating the water balance during it and assessing yields at the end. Focusing on food security outlooks for East Africa in late 2008, Funk describes how data from NASA's Aqua and QuikSCAT satellites can be used to track moisture and wind conditions over the Indian Ocean and Africa, and how these help anticipate hydrologic conditions in the future to predict shortfalls.

Funk emphasises the need to combine such data with socio-economic analyses of, for example, crop prices, grain stores, political conditions and agricultural inputs. This will help maximise the accuracy and effectiveness of early warnings of drought and food shortages.