ABSTRACT
Droughts have significant economic and societal impacts. This chapter offers an overview of the state of science and practice in Monitoring, Forecasting, and Understanding Droughts. It highlights the research advances in these areas, and the remaining challenges and opportunities. The chapter discusses land surface models (LSMs)-based drought prediction capabilities. The US Drought Monitor (USDM), which has been providing a weekly assessment of drought conditions throughout the United States since 1999, represents the nation's current state-of-the-science operational monitoring capability. The overarching goals of drought prediction research have been to improve the understanding of physical mechanisms of drought, sources of predictability, and the nature and magnitude of unpredictable variability. In drought monitoring research, one major success of the last decade is the development of the LSM-based North American land data assimilation system (NLDAS) and its application to operational drought monitoring. Another success is the expanded use of remotely sensed data in drought monitoring efforts, especially data describing vegetation and evapotranspiration.
