Atmospheric Circulation During December 1970 Through February 1971

Abstract

Abstract National Meteorological Center wind data from December 1970 to February 1971 were used to compute the 90-day winter mean eddy kinetic energy, and the energy exchange between waves and between waves and zonal mean flows at 200 mb, over mid-latitude (33.0–48.1°N), subtropical (10.0–28.7°N) and tropical (5.0°N–14.8°S) belts. In the mid-latitude (subtropical) belt, waves of wavenumbers 1–10 lose (gain) energy to (from) zonal mean flows with large contributions from wavenumbers 2–3 and 5–7. Energy exchanges over the tropical belt are quite different from those in the mid-latitude and subtropical belts with conspicuously small wave-zonal flow interaction and somewhat larger wave-wave nonlinear interactions. Wavenumber 8 receives substantial energy via wave-wave interaction with other waves in both the sub-tropical and tropical belts. Sometimes the 200 mb eddy kinetic energy was well above its 90-day winter mean at all latitudinal belts. Such occasions were characterized by an extremely strong jet strea...