Equatorial Atmosphere

Two years of rocket wind data from Ascension Island (8°S) and Barking Sands, Hawaii (22°N), were used in conjunction with routine balloon observations in a study of the mean zonal wind distribution and the annual and semiannual zonal wind variations in the equatorial stratosphere and lower mesosphere. Four main results were found: (1) The long‐term mean zonal wind near the equator is easterly in the stratosphere and westerly in the lower mesosphere. The speed of the easterlies varies from near zero at the tropopause to about 15 m sec−1 between 30 and 40 km. (2) The annual cycle increases rapidly in amplitude outward from the equator. At Ascension Island the maximum amplitude is located at a height of 40 km and has a value of about 20 m sec−1. The maximum value of nearly 50 m sec−1 at Barking Sands occurs at a higher level, approximately 60 km. Maximum westerlies are achieved in early winter or late fall near the stratopause and a month or two later in the lower stratosphere. (3) The semiannual cycle is strongest at the equator, where it attains a maximum amplitude of 30 m sec−1 near 50 km. Strongest west winds occur shortly after the equinoxes in the lower mesosphere and progressively later at the lower levels. (4) In summer a core of maximum east winds (or jet stream) appears to exist at 15° latitude in the layer between 40 and 45 km.

EquatorAtmosphere (last edited 2019-03-31 17:25:57 by KeithLofstrom)