Estimation of turbulence energy dissipation rate and vertical eddy diffusivity with the MU radar RASS

We have conducted RASS (Radio Acoustic Sounding System) observations with t he MU (Middle and Upper atmosphere) radar on 28-31 July 1994 at Shigaraki, Japan (34 degrees 51' N, 136 degrees 06' E) and determined the characterist ics of turbulence energy dissipation rate (epsilon) and vertical eddy diffu sivity (K) in the troposphere and lower stratosphere. We have first examine d the accuracy of the Brunt Vaisala frequency squared (N-2) derived from RA SS temperature profiles. Then, epsilon and K are determined by using N-2 an d the Doppler spectral width of turbulence echoes (sigma(turb)(2)) We found that the structures of epsilon and K are sometimes affected by the local v ariations of N-2. We found that sometimes epsilon became small, even though sigma(turb)(2) was large, because N-2 was small. On the contrary, K was en hanced due to small N-2, although sigma(turb)(2) was small. (C) 1999 Elsevi er Science Ltd. All rights reserved.