Intraseasonal Surface Fluxes in the Tropical Western Pacific and Indian Oceans from NCEP Reanalyses

Abstract

Abstract Reliability of the surface fluxes from National Centers for Environmental Prediction (NCEP) reanalyses is assessed across the warm pool of the western Pacific and Indian Oceans. Emphasis is given to the spatial distribution and coherence of the fluxes on intraseasonal (25–100 day) periods, as intraseasonal variability predominates the subseasonal variability across the warm pool. Comparison is made with surface fluxes estimated from data collected at a mooring during the Coupled Ocean–Atmosphere Response Experiment and with independent gridded estimates based on operational wind and surface pressure analyses and satellite observations of rainfall, shortwave radiation, and outgoing longwave radiation. In general, fluxes that depend primarily on surface wind variations (e.g., stress and latent heat flux) agree more favorably than fluxes that are largely dependent on fluctuations of convection (e.g., surface shortwave radiation and freshwater or precipitation). In particular, the intraseasonal varia...