Wavenumber spectra of the Mediterranean Sea winds derived from the NASA QuikSCAT data

The paper describes some of the results obtained computing and analyzing the zonal and meridional spectra of the wind kinetic energy in the wavenumber space, derived from the QuikSCAT wind data over the Mediterranean Sea. To compute the spectra, a technique based on the Lomb periodogram has been used to overcome the problem of missing data, that occurs often in the Mediterranean basin, due to its morphology. The same technique has been applied to wind data from two atmospheric global models (NCEP and ECMWF). The comparison among the spectra has permitted to define the wavelength range where models under estimate the energy, which resulted for wavelengths < 500 km. The analysis on the spectral decay law k(gamma), carried out through a statistical method based on the Monte Carlo simulations, has shown that the gamma = -5/3 decay, which accounts for the energy transfer from high to low wavenumbers, holds for wavelengths 900 km < lambda < 1300 km for zonal and 900 kin < lambda < 1000 km for meridional kinetic energy, while the gamma = -3 decay occurs at 700 km < lambda < 900 km for zonal and 600 km < lambda < 900 km for meridional. At shorter wavelengths lambda < 600 km, the decay is gamma = -3.3.