A Facility and Examples for Evaluating Surface Fluxes from Models and Observations

To facilitate the evaluation and monitoring of weather and climate model forecast skills and satellite-based products against high quality in-situ observations, a data repository for collocated model forecasts and simulations, satellite products, and in-situ observations has been created under the support of various World Climate Research Program (WCRP) Working Groups. Intercomparison of the collocated “data” over a one-year period for sea surface wind is presented here as one example of applications. The comparison indicates potential areas for model and satellite product improvements.

The daily wind measurements from eleven OceanSITES buoys located in the Pacific, Indian, and Atlantic Oceans are used as the reference data set. The satellite-based product blends measurements from multiple satellite observations. The model winds come from three international operational Numerical Weather Prediction (NWP) Centers (Europe, Germany and Japan) and one climate forecast Reanalysis (USA).

The surface winds from all five surface wind products correlate well with buoy winds. The Reanalysis winds have generally higher cross-correlation coefficients and smaller root-mean- square (RMS) errors when compared to other products analyzed here. On systematic speed bias against the buoys, the blended satellite wind speed is 0.41 m/s lower on average, and the Reanalysis and NWP models are 0.78 to 0.89 m/s lower, respectively. On wind direction, systematic positive/negative biases are found in the central/east central Pacific Ocean, respectively.