Creating an Eight-Member Ocean Reanalysis Ensemble for use by the Climate Modeling Community.

Research shows that ensemble-averaged ocean reanalysis generally outperform individual ocean reanalyses products. The ensemble average and spread provide useful information to evaluate climate models. This presentation describes an effort to produce estimates of ensemble average from several ocean reanalysis products that cover the 1979-2010 period. We highlight the challenges and methods used in horizontal regridding and vertically interpolating the monthly fields to a common 1x1 degree latitude-longitude grid and common depths. The ensemble-averaged and the regridded, interpolated data are published in the Collaborative REAnalysis Technical Environment Intercomparison Project (CREATE-IP) in the Earth System Grid Federation (ESGF). This work is a collaboration between NASA Goddard Space Flight Center and the CLIVAR Global Synthesis and Observations Panel (GSOP) to develop ensemble average and spread products for monthly, 3-D potential temperature, salinity, and zonal and meridional velocities from eight ocean reanalyses: National Centers for Environmental Prediction (NCEP) Climate Forecast System Reanalysis (CFSR), Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC ), European Centre for Medium-Range Weather Forecasts (ECMWF) Ocean Reanalysis System 4 (ORA-S4), ECMWF Ocean ReAnalysis Pilot 5.0 (ORAP5.0), German Estimating the Circulation and Climate of the Ocean (GECCO2), NOAA Geophysical Fluid Dynamics Laboratory (GFDL) Monthly Ensemble Means, NOAA Global Ocean Data Assimilation System (GODAS) and Multivariate Ocean Variational Estimation (MOVE) Meteorological Research Institute Community Ocean Model (MRI.COM-G2i).