Evaluation of a hybrid satellite- and NWP-based turbulent heat flux product using Tropical Atmosphere-Ocean (TAO) buoys

Gridded hybrid turbulent heat flux fields were created by applying the state- of- the- art Coupled Ocean- Atmosphere Response Experiment ( COARE) version 3.0 bulk algorithm to state variables ( sea surface temperature, winds relative to currents, air temperature, and air specific humidity) derived from either numerical weather prediction ( NWP) reanalysis ( National Centers for Environmental Prediction - National Center for Atmospheric Research ( NCEP- NCAR) reanalysis ( NCEP1), NCEP reanalysis- 2 ( NCEP2), and 40- year European Centre for Medium- Range Weather Forecasts ( ECMWF) reanalysis ( ERA40)) or satellite sensors ( QuikSCAT winds and Tropical Rainfall Measuring Mission ( TRMM) Microwave Imager microwave sea surface temperature). The most accurate source for each state variable was determined by comparing variables to tropical Pacific Tropical Atmosphere- Ocean ( TAO) buoy observations for the years 2000 - 2001. The selected sources were as follows: QuikSCAT for winds relative to currents, ERA40 for air temperature and specific humidity, and TRMM Microwave Imager fusion product for sea surface temperature. Errors in latent and sensible heat fluxes to state variables were analyzed. Specific humidity errors contributed the most to errors in latent heat flux ( LHF). Overall, the hybrid LHF product had a bias of - 5.8 W m(-2) and a standard deviation of difference of 16.2 W m(-2), which is comparable to the accuracy of LHF derived from TAO measurements.