Seasonal variability of turbulence parameters at 2 to 21 km from MST radar measurements at Vandenberg air force base, California

Abstract

Seasonal profiles of the turbulent kinetic energy, eddy dissipation rate, inner scale of turbulence, and vertical eddy diffusivity are presented from observations using the VHF Doppler profiling radar at Vandenberg (VBG) Air Force Base, California, over 4 calendar years from 2 to 21 km. Results are displayed seasonally both as a function of distance above the surface and relative to the tropopause. The VBG radar is located in the littoral region of southern California with a pronounced marine boundary layer; results are compared to those derived from other radars with similar performance located in different climatic regimes and terrain conditions. Turbulent kinetic energy values at VBG are between the higher values found at White Sands Missile Range (WSMR), New Mexico, which is located in a semiarid valley, and the site at Gadanki, India, except under Indian monsoon conditions. The same trend in general is found for the eddy dissipation rate for the same three sites although differences between the two U.S. sites are small. Inner scale profiles show the largest values at Gadanki and the smallest at WSMR with VBG estimates in the middle. Eddy diffusivity values at WSMR and VBG are in general slightly smaller than those found with the MU radar near Kyoto, Japan, but are greater than the values found in the stratosphere in Gadanki, India. All turbulence parameters show significant correlations with wind speed. Copyright 2005 by the American Geophysical Union.