North American Multi-Model Ensemble effort at GMAO

NMME banner The GMAO is taking part in the North American Multi-Model Ensemble project (NMME), a collaborative multi-agency effort that is led by NOAA and includes NASA, the NSF, and the DOE. The goals of this effort are to capitalize on the modeling investments within the U.S. and elsewhere to produce routine, real-time, multi-model ensembles of intra-seasonal-to-interannual (ISI) predictions. The forecasts are provided to the NOAA Climate Prediction Center (CPC) on an experimental basis for evaluation and consolidation as a multi-model ensemble prediction system. GMAO benefits from this collaboration in a number of ways, including a near-real-time and on-going evaluation of our GEOS prediction system by numerous users with a wide range of potential applications.

Each month, the GMAO contributes an 11-member ensemble of global nine-month GEOS forecasts to the NMME. The GEOS ensemble is comprised of a mix of lagged forecasts (initialized every five days) and simultaneous forecasts (six forecasts initialized on the start date that is closest to the beginning of the month). The simultaneous ensembles are generated from breeding and other simpler perturbation approaches. Initial conditions are determined from GMAO’s reanalyses of the atmosphere, land and ocean. The multi-model ensemble approach has proven extremely effective at quantifying prediction uncertainty due to uncertainty in model formulation, and has proven to produce better prediction quality (on average) than any single model ensemble.

The GMAO GEOS Seasonal Forecast data is delivered to NMME each month. Results can be found on the NMME webpage North American Multi-Model Ensemble page. More details on the GMAO's seasonal forecasting system are available on the Seasonal-Decadal Analysis and Prediction web page.