Pacific Ocean wind stress and surface heat flux anomalies from NCEP reanalysis and observations: Cross-statistics and ocean model responses

Wind stresses and surface heat fluxes over the Pacific Ocean from the Natio nal Center for Environmental Prediction (NCEP) reanalysis and the comprehen sive Ocean-Atmosphere Data Set (COADS) (blended with FSU tropical wind stre sses) are compared over a common time interval (1958-1997) in their statist ics anal in the responses that they induce in sea surface temperature (SST) and heat storage when used to force an ocean model. Wind stress anomalies from the two data sets are well correlated in the midlatitude extratropics, especially in the highly sampled North Pacific. In the tropics and subtrop ics, low correlations were found between the two wind stress data sets. The amplitudes of the stress variations of the two data sets are similar in mi dlatitudes, but in the tropics NCEP wind stresses are weaker than the LOADS /FSU stresses, especially on interannual timescales. Surface heat flux anom alies from the two data sets are well correlated on interannual and shorter timescales in the North Pacific Ocean poleward of 20 degreesN, but they ar e poorly correlated elsewhere and on decadal timescales. In the extratropic s the amplitudes of the heat flux variations of the two data sets are compa rable, but in the tropics the NCEP heat fluxes are weaker than those of COR DS. Ocean model hindcasts driven by bath data sets are also compared: The m idlatitude SST hindcasts were superior when using the NCEP flux anomalies w hile tropical SST hindcasts were equally skillful for the two hindcasts whe n considering all climatic timescales. The spatial and temporal sampling ra tes of the LOADS observations and their consequent impacts on constraining the NCEP reanalysis appear to be the main factors controlling the results f ound here.