NASA Ocean Vector Wind Science Team Meeting

Professor Mark Bourassa Florida State University 200 R.M. Johnson Building, 2035 E. Paul Dirac Drive, PO Box 3062840 Tallahassee, FL 323062840 USA [email protected] Barry Vanhoff (Oregon State University) David E. Weissman (Hofstra University) Contributed Talk Calibration/Validation and definitions Scatterometers have long been considered to respond to surface turbulent stress. They have been calibrated to wind-like quantities (equivalent neutral winds) due to the paucity of stress observations. Equivalent neutral winds are winds that have been modified to be more physically consistent with stress. However, for historical reasons, equivalent neutral winds were made consistent with friction velocity, which is the square root of the kinematic stress (the stress divided by atmospheric density). If scatterometers do respond to stress, this approach introduces an error (a gain) in wind speed related to the square root of atmospheric density. For scatterometerderived stress, the error would be proportional to density raised to the 1 to 1.5 power, depending on the wind speed. This dependency on air density is examined, with the goal of showing that scatterometer backscatter is more closely a function of surface stress than wind speed or equivalent neutral wind. The influence of air density is a gain, a proportional increase remove 10/09/2008 Displaying Abstracts