A SPECIAL OSCILLATION OF ZONAL MEAN TEMPERATURES OF THE MIDDLE ATMOSPHERE

Through an analysis of SAMS temperature data of the Nimbus 7 satellite , an oscillation of the zonal mean temperature superimposed on the sea sonal trend is discovered. Its character is to oscillate synchronously on the constant pressure surface and to form standing waves in the ve rtical direction. It is proposed that this oscillation may be a charac teristic mode of the atmosphere, and the zonal wavenumber m = 0, merid ional wavenumber n = 0, and the geopotential eigenfunction is P-0(0), which indicates a simple vertical motion of the atmosphere. The existe nce of reflection levels in the vertical direction may be the causes f or the formation of these standing waves and the harmonic oscillations , whose fundamental period is similar to 16 days. (C) 1998 Elsevier Sc ience Ltd. All rights reserved.