The Pacific-North American pattern associated diabatic heating and its relationship to ENSO

Abstract

The Pacific-North American (PNA) pattern associated atmospheric diabatic heating is examined by linearly isolating the influence of El Niño-Southern Oscillation (ENSO). Both the vertically integrated and three-dimensional (3D) diabatic heating are calculated on the basis of NCEP/NCAR reanalysis. The PNA-related heating is dominated by anomalies in the eastern Pacific, with a north-south dipole structure in mid-latitudes and in the northern subtropics. The tropical heating anomalies are rather weak, remarkably different from those related to ENSO variability, and may be characterized by the heating nonlinearity with anomalies in the vicinity of the western Pacffic. The results provide further evidence of the independence of the PNA on ENSO from the diabatic heating point of view. Copyright © 2007 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.