Variations of Winds and Turbulence Seen by the 50-MHz Radar at White Sands Missile Range, New Mexico

Abstract

The mean vertical profiles of the winds from about 5 to 20 km at White Sands Missile Range, New Mexico, are described. The variability of wind speed, spectral width, volume reflectivity calibrated as CN2, and vertical wind shear are documented as functions of season and of time of day using observations taken from 1991 through April 1994 with the 50-MHz profiling radar. The mean meridional winds are from the south at about 1-3 m s?1 during every season except autumn, and mean zonal winds have a broad jet near the tropopause with maximum speed over 30 m s?1 during the winter. The mean vertical velocity is downward at about 5 cm s?1 in the troposphere and is weakly upward in the lower stratosphere. The shear of the mean wind and the mean wind shear have small interseasonal variability. The variance over 1-h periods of all three wind components, the spectral width, and CN2 have lognormal frequency distributions. The variance of the meridional wind speed is greater than that of the zonal wind speed in the troposphere, but in the stratosphere during winter and spring the variance of the zonal wind speed is greater. The mean profiles of logCN2 in the stratosphere are nearly constant with altitude and from season to season, ranging over only a few decibels. Diurnal cycles of wind speed have amplitudes on the order of 1 m s?1, but the phases are highly variable with height and season, suggesting strong local topographic control of the observed diurnal cycles. The diurnal cycles of CN2, spectral width, and of the variance of the vertical velocity have the largest amplitudes in the troposphere where the daily maxima are during the afternoon.