3.1
Bulk Parameterization of Air-Sea Fluxes: Updates and Verification for the COARE Algorithm
C. W. Fairall, NOAA/ERL/ETL, Boulder, CO; and E. F. Bradley, J. E. Hare, A. A. Grachev, and J. B. Edson
Direct measurement of air-sea fluxes remains a technological challenge that is practiced by only a few research groups around the globe. Accurate measurements of fluxes from ships and buoys in a routine, unattended mode are still not practical. Thus, virtually all estimates of global or regional fluxes are obtained from bulk flux models, which use more easily obtained near surface meteorological data. Ultimately, bulk model coefficients must be traced to direct measurements obtained in very demanding intensive field programs. In the last decade great progress has been made on several technological fronts to improve the quality of the direct flux data. Similarly, several theoretical advances in representations of interfacial and boundary-layer processes has removed earlier pathological problems and linked the parameterizations more closely to the underlying physics. In 1996 version 2.5 of the COARE bulk algorithm was published and has become one of the most frequently used in the air-sea interaction community. In this paper we describe steps taken to improve the algorithm and a comparison with new data. This new version of the algorithm (COARE 3.0) was based on published results and 2777 one-hour covariance flux measurements in the ETL inventory. To test it, we added 4439 new values from field experiments between 1997 and 1999, which now dominate the database, especially in the wind speed regime beyond 10 ms-1 where the number of observations increased from 67 to about 800. After applying various quality controls, the database was used to evaluate the algorithm in several ways. The average (mean and median) model results agreed with the measurements to within about 5% for moisture from 0 to 20 ms-1. For stress, the covariance measurements were about 10% higher than the model at wind speeds over 15 ms-1 while inertial-dissipation measurements agreed closely at all wind speeds. In the paper we will discuss measurement issues, how these results compare with classic results from other field programs and models, and prospects for extending beyond 20 ms-1.
Session 3, Part 1: Air-sea Fluxes and interfacial processes
Monday, 10 February 2003, 4:00 PM-5:30 PM
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