A CONSISTENCY CHECK OF 3 RADAR METHODS FOR MONITORING EDDY DIFFUSION AND ENERGY-DISSIPATION RATES THROUGH THE TROPOPAUSE

The capability of Stratosphere-Troposphere radars for estimating the e nergy dissipation rate epsilon and eddy diffusivity K-Z is still stron gly questioned because the methods proposed in the Literature generall y make use of assumptions not yet fully justified. In order to clarify this point, two assessment campaigns, using the high-resolution UHF P ROUST radar, have been performed. Results obtained with both ''width'' and ''power'' methods are systematically compared with a statistical approach proposed by Dewan [1979] and Woodman and Rastogi [1984], usin g the thickness and lifetime of the turbulent layers. The epsilon and K-Z derived from these three methods in observed turbulent fields near the tropopause level are found to be reasonably similar for turbulent layers whose thickness L(T) is smaller than 300 m. For the thicker tu rbulent patches (L(T)>300 m), the statistical approach using turbulent thickness tends to give eddy diffusivity values greater than those ob tained with width and power methods. This discrepancy could be due to the nonhomogeneity of the turbulence in these large turbulent structur es.