Equatorial Zonal Wind in the Middle Atmosphere Derived from Geopotential Height and Temperature Data

Abstract

This paper examines the feasibility of deriving the zonal wind at the equator using monthly mean temperature and geopotential height data from satellite and radiosonde/rocketsonde measurements. Using climatological data of the stratosphere and mesosphere based on monthly mean Nimbus 5 Selective Chopper Radiometer and Nimbus 6 Pressure Modulator Radiometer measurements, and stratospheric monthly mean data from the National Meteorological Center for 1979?86, we present meridional cross sections and time profiles of the zonal wind in the tropical middle atmosphere. The derived zonal wind at the equator reproduces the mean climatology of the tropical middle atmosphere as well as the general characteristics of the equatorial quasi-biennial (QBO) and semiannual oscillations (SAO) observed in monthly mean radiosonde and rocketsonde data. Although the amplitude of the derived wind QBO is for the most part underestimated relative to direct wind measurements, the amplitude of the derived wind SAO compares fairly well with rocketsonde observations.