Seasonal-Scale Drought Forecasting in Africa and the Middle East Using the NASA Land Information System (LIS)

Drought and water scarcity are among the most important issues facing semi-arid regions within Africa and the Middle East. A seamless and effective drought monitoring and early warning system is needed to facilitate a proactive drought management approach to mitigate socio-economic losses. In this presentation, we report on the ongoing development and validation of a seasonal scale drought forecasting system, based on NASA’s Land Information System (LIS) and downscaled dynamical seasonal climate forecasts. This system is specifically being developed to improve upon the existing drought monitoring and early warning efforts of the Famine Early Warning Systems Network (FEWS NET) and the Middle East-North Africa (MENA) Regional Drought Management System, both of which support international (e.g. USAID), national and regional stakeholders.

Seasonal-scale drought forecasting skill is derived from the initial hydrologic state and seasonal scale climate forecasts. Therefore, to better estimate the initial hydrologic state satellite-based soil moisture and terrestrial water storage (TWS) retrievals are assimilated with LIS land surface models (LSMs), i.e., NASA’s Catchment and the Noah Multi-Physics (MP) model, which incorporate prognostic water table schemes. Seasonal scale climate forecasts are taken from downscaled and bias-corrected versions of NASA’s Goddard Earth Observing System Model, version 5 (GEOS-5), and NOAA’s Climate Forecast System, version 2 (CFSv2) forecast datasets. Long-term historical reconstructions of drought conditions are generated by driving the LSMs for 30+ years with NASA’s Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2), and the Climate Hazards Group InfraRed Precipitation with Stations (CHIRPS) daily precipitation dataset. The LSMs’ total runoff is routed through the Hydrological Modeling and Analysis Platform (HyMAP) to simulate surface water dynamics, which provides an additional means of validating hydrological drought events against available long-term in situ streamflow data. For this presentation, drought forecasts of soil moisture, ET, TWS and streamflow are evaluated at different lead times out to 6 months for East Africa, which encompasses some of the most food and water insecure regions.