The Observed Annual Cycle in the Meridional Transport of Atmospheric Energy

Abstract

The annual cycles in the atmospheric storage and in the meridional transport of energy are discussed. The calculations are based on a five-year sample from more than 500 radiosonde stations mainly located in the Northern Hemisphere. All statistics represent values integrated vertically between the earth's surface and 75 mb and horizontally along a latitude circle. Several new and interesting features of the eddy and mean transports of potential energy, sensible heat, latent heat and kinetic energy become apparent by the breakdown according to calendar month. In December through February more than half of the sensible heat is transported poleward by the standing eddies. The transient eddy heat flux does not peak in winter but in April and November. The strong annual cycle in the tropical Hadley circulation does not contribute to the poleward transfer of energy for the year as a whole.