Climate Diagnostics and Prediction

Near Real Time Seasonal Forecasts

Seasonal-to-Interannual coupled forecasts are conducted on an experimental basis in near real time with the GEOS-5 AOGCM. A suite of 30-year 9-month hindcasts is available, initialized with the GEOS-OIDAS, MERRA-Land, and MERRA atmospheric fields. Forecasts are initialized every 5 days, with 7 ensemble members initialized on the date closest to the beginning of the month. The ensemble members are generated by coupled model breeding and by independent perturbations in the ocean and atmosphere. The experimental forecasts and historical performance can be viewed at the Experimental Climate Forecast web page. Every month the forecasts of SST, air temperature at 2m (T2m), and precipitation are delivered to the National Multi-Model Ensemble.

Since the GEOS-5 seasonal forecasts are global with an initialized sea-ice distribution, the GMAO has begun (June 2013) to contribute to the Sea Ice Outlook ( for September Sea Ice extent organized by the Study of Environmental Arctic Change (SEARCH) and the Arctic Research Consortium of the U.S. (ARCUS).

Decadal Predictions

The GEOS-5 AOGCM has been used for a suite of decadal predictions, contributed to CMIP5 and published on the Earth System Grid with the designation NASA GMAO. The forecast suite consists of a 3-member ensemble initialized each 1 December from 1960 to 2010.


The GMAO engages in research to understand drought and its predictability. GEOS-5 and MERRA have been used to examine drought in the U.S. in 2011 and 2012. Read about this recent study.

An Atlas of Weather and Climate Extremes over the Americas (beta version) is available.

The MERRA Atlas provides information on climate variability.