LOWER-TROPOSPHERIC HEAT-TRANSPORT IN THE PACIFIC STORM TRACK

The relative effects of dynamics and surface thermal interactions in d etermining the heat flux and temperature fluctuations within the lower -tropospheric portion of the Pacific storm track are quantified using the probability distribution functions (PDFs) of the temperature fluct uations and heat flux, Lagrangian passive tracer calculations, and a s imple stochastic model. It is found that temperature fluctuations damp to the underlying oceanic temperature with a timescale of approximate ly 1 day but that dynamics still play the predominant role in determin ing atmospheric heat flux, due to eddy mixing lengths within the storm track of less than or equal to 5 degrees latitude. These results are confirmed by the favorable comparison of the PDFs of the model-generat ed and observed temperature fluctuations and heat flux. The implicatio ns of strong thermal damping in the lower troposphere are discussed an d speculations are made regarding the effect of such damping upon baro clinic eddy life cycles and the general circulation.