A Two‐Week Evaluation of Available Potential Energy and Kinetic Energy from NMC and ECMWF Analyses

Abstract

Available potential energy and kinetic energy distributions for the Northern Hemisphere computed from the FGGE Level IIIa analyses produced at the National Meteorological Center (NMC) and the Level IIIb analyses prepared at the European Centre for Medium Range Weather Forecasting (ECMWF) are presented for a two?week period 14?27 February 1979. The most significant difference between the two datasets appear in the eddy components, where the hemispheric ECMWF values are smaller than the NMC values. This difference is found at almost every latitude in the APE distributions and in tropical and polar latitudes in the KE distributions. Vertical cross sections and 250 mb height patterns for three individual days show smoother and weaker short wave features over the oceans in the ECMWF analyses. Jet streak maxima at 250 mb tended to be stronger in the NMC analyses. These results are consistent with those from previous studies which noted smaller energy values in the ECMWF analyses compared to NMC and GFDL analyses.