Meridional Variation of Lower Stratospheric Gravity Wave Activity

A Quick Look at Hakuho-Maru J-COARE Cruise Rawinsonde Data

Abstract

Meridional variation of the lower stratospheric gravity wave activity in the western Pacific region (14°S-25°N)is investigated on the basis of vertical wavenumber spectra analyzed from temperature and wind data observed by rawinsondes of the Hakuho-maru J-COARE cruise during November 1 and December 4, 1992. The dominant vertical wavelength of gravity waves is ∼2.7km, which is distinguished from that of Kelvin waves (∼4km). The power spectral densities of the 4.0km, 2.7km and 2.0km wavelength components for temperature, zonal wind and meridional wind in an altitude range of 14-22km are plotted as functions of latitude. In general, they are obviously larger than those obtained in the mid-latitude regions and seem to have maxima near the equator.