Mesoscale Turbulence Spectra over The Indian Ocean

Abstract

Doppler wind data obtained over the Indian Ocean during the 1964 Indian Ocean Expedition are analyzed in terms of power spectrum estimates. Peculiarities in the computed distribution of the mean horizontal kinetic energy associated with mesoscale (?1?100 km) motions are noted in light of energy input from mean wind shear and energy export to the density field in a stably stratified atmosphere. The data indicate that quasi-horizontal eddies 10 km in size derive their energy mainly from mean horizontal wind shear at a wavenumber around 1?2 cycle km?1, and that eddies of a few kilometers in diameter are approximately two-dimensionally isotropic.