The Naval Research Laboratory ocean surface flux (NFLUX) system: Satellite-based turbulent heat flux products

The Naval Research Laboratory ocean surface flux (NFLUX) system provides satellite-based surface state parameter and surface turbulent heat flux fields operationally over the global ocean. These products are presented as an alternative to using numerical weather prediction models-namely, the U.S. Navy Global Environmental Model (NAVGEM)-to provide the surface forcing to operational ocean models. NFLUX utilizes satellite sensor data records from the Special Sensor Microwave Imager/Sounder (SSMIS), the Advanced Microwave Sounding Unit-A (AMSU-A), the Advanced Technology Microwave Sounder (ATMS), and the Advanced Microwave Scanning Radiometer-2 (AMSR-2) sensors as well as satellite environmental data records from WindSat, the Advanced Scatterometers (ASCAT), and the Oceansat scatterometer (OSCAT). The satellite data are processed and translated into estimates of surface specific humidity, surface air temperature, and 10-m scalar wind speed. Two-dimensional variational analyses of quality-controlled satellite data, in combination with an atmospheric-model field, form global gridded surface state parameter fields. Bulk formulas are then applied to produce surface turbulent heat flux fields. Six-hourly analysis fields are created from 1 January 2013 through 31 December 2013. These fields are examined and validated against in situ data and NAVGEM. Overall, the NFLUX fields have a smaller bias, lower or similar root-mean-square error, and increased skill score relative to those of NAVGEM.