Zonal Wind Reversal between 30 and 80 km over the Southwestern United States

Abstract

The reversal of winds between 30 and 80 km near the equinoxes is described with time-height cross sections. Data are from meteorological rocket soundings at White Sands Missile Range, N. Mex. (fall 1960, 1961, 1962; spring 1961, 1962) and Pacific Missile Range, Point Mugu, Calif. (spring 1961, 1962; fall 1961). The three fall reversals indicate that the reversal begins above 60 km and progresses downward at about one to four km per day. From the observation of the spring 1961 reversal, it appears that this reversal initially occurred above 45 km and progressed downward, while easterlies of smaller magnitude began to appear at about the same time below 30 km and progressed upward. The spring 1962 reversal, however, did not have this feature. The differences in the years may be explained in part by the time lag of the stratosphere warming. An average downward progression of two to five km day−1 was observed for the spring 1961 reversal and about one to three km day−1 for spring 1962. The spring and fall reversals of White Sands and Point Mugu were in close agreement in time and character.