RESEARCH OVERVIEW
Research in 
the GMAO emphasizes the use of satellite observations to address questions about climate variability, water and energy budgets, composition, and weather and climate prediction. Global ocean, atmosphere and land surface models are developed as components of assimilation and forecast systems, as well as for addressing the weather and climate research questions identified in NASA's science mission. Our research includes topics such as the generation and analysis of comprehensive climate-relevant data sets to support studies of variability and change.
Our modeling strategy is driven by the need to have a comprehensive global model valid for both weather and climate and for use in both simulation and assimilation. The atmospheric component must be a state- of-the-art weather prediction model, and the land and ocean components must accurately represent processes important for modeling subseasonal to decadal timescales. The GEOS system of models integrates the various components under the Earth System Modeling Framework (ESMF) using MAPL, a utility layer that facilitates the use of ESMF.
The GMAO's assimilation research is focused on enhancing the use of NASA satellite data for weather and climate prediction and for climate analyses. Guidance on observing system issues is provided through Observing System Experiments (OSEs) and through an emerging Observing System Simulation Experiment (OSSE) capability.
Climate Diagnostics and Prediction
One of the key questions to be addressed in NASA's science mission is how well transient climate variations can be understood and predicted. The GMAO explores the impact of coupled prediction strategies and observations on prediction skill at subseasonal to decadal timescales, with a focus on identifying sources of predictability and the role that specific observations play in extending prediction skill. In addition to trying to improve skill in predicting ENSO and other short-term climate variability, our research focuses on the sources and predictability limits of long-term droughts, on weather-climate connections, and on attribution of weather extremes.
The GMAO has undertaken a reanalysis for the satellite era —MERRA— using the GEOS-5 AGCM and its atmospheric data assimilation system from 1979 to the present. MERRA is continuing as a real-time climate analysis. The GMAO continues efforts to improve on atmospheric reanalyses at the same time as working a Integrated Earth System Analysis (IESA) with our atmosphere, ocean and land surface data assimilation systems.
