Preliminary Results from the ETL Open Ocean Air-Sea Flux Database

From 1991 through 1999 the ETL Marine and Air-Sea Interaction Research Group made direct measurements of air-sea turbulent and radiative fluxes during 17 field programs in the open ocean. The majority of the cruises were from conventional research ships but two were from R/P FLIP. All data were taken with the ETL seagoing flux system (a second generation system was implemented in 1996). All cruises feature direct covariance (ship-motion corrected) momentum, sensible heat, and latent heat fluxes except CSP where there was a logging problem with the high speed data. All cruises also feature very good bulk meteorological variables (including rawinsondes) plus longwave and solar radiative fluxes. A few have covariance measurements of CO2 fluxes.

We are now in the process of reprocessing these data to put them in a common format and create a single database of fluxes and bulk variables for intercomparisons with flux parameterizations, operational forecast models, and satellite data. In this paper we will present results of analysis using 13 of the 17 cruises. This data base constitutes 7216 hours of observations obtained between 12 S and 57 N latitudes. After editing for data quality, some 4000-5000 good flux observations are usable. This is a factor of ten greater than the number of observations yielded in a typical 30-day ship deployment. The average 10-m wind speed is 6 m/s; there are approximately 30 hours of useful fluxes at 10-m wind speeds greater than 18 m/s and 400 hours at wind speeds less than 2 m/s. We will present a comparison of the data with the latest version of the COARE bulk flux algorithm and an analysis of cloud forcing of surface radiative fluxes.