Climate variability and change in East Africa

Climate variability and change in East Africa is determined using climate data and regional climate model simulations. Our focus is on East Africa, a region with a history of droughts and floods, whose complex terrain and varied climates are not resolved by global climate models. While many climate studies use 2.5˚ spatial grids or national-level data, our unit of analysis is 1˚ ≈ 100 km spatial scale, which accommodates regression and other (spatial) statistical analysis of climate and environmental variables.

Monthly land surface data are used to determine climate variability at local and regional scales for the period 1970-2009. The Standardized Precipitation Index at the six-month time scale (SPI6) is the primary measure used. For annualized SPI6, drought severity varied spatially, temporally, and across climate zones. Variability associated with phenomena such as El Niño-Southern Oscillation was evident. In general, most of the domain was near normal or became slightly wetter between 1970 and 2009. For the same period, the temperature remained near normal or became slightly warmer. Variability is also measured by daily minimum and maximum temperature anomalies.

For the final study phase, the Nested Regional Climate Model (NRCM) is used to assess future climate variability. NRCM simulations with 12-km grids resolve topography and land-use variations that may be crucial to determining local impacts of large-scale climate changes.

This study is part of a pilot study of climate and armed conflict. It identifies climate trends at scales that are useful for agro-ecological impacts, which are factored into conflict regression models.