Diabatic heating associated with El Niņo-Southern Oscillation (ENSO) variability is residually diagnosed from the European Centre for Medium-Range Forecasts (ECMWF) and
National Centers for Environmental Prediction (NCEP)-National Center for Atmospheric Research (NCAR) atmospheric reanalysis datasets during the overlapping 1979-93 period.
Quantitative characterization of the horizontal and vertical structure of ENSO heating anomalies, including estimates of uncertainty, provides observationally constrained validation
targets for GCM physical parameterizations.
The diagnosed ENSO heating anomalies have similar horizontal structure, but the vertically averaged ECMWF heating is stronger and in better agreement with the Xie-Arkin
precipitation anomalies, particularly with respect to precipitation reduction over the western tropical Pacific. Comparison of heating vertical structures in the central equatorial Pacific
shows ECMWF heating to be considerably stronger in the lower troposphere, where it exhibits a local maximum.
The ENSO covariant tropospheric temperature in the two reanalyses was also examined along the equator and found to have an intriguing vertical structure, with sizeable amplitude
in the lower and upper troposphere and vanishing amplitude in between. The largest temperature anomalies in the lower troposphere are at the surface, and the ECMWF one is about
50% stronger.
The three-dimensional heating anomalies diagnosed from the reanalyses are used to evaluate the ENSO heating distribution produced by NCAR's Community Climate Model,
version 3 (CCM3) atmospheric GCM, when integrated in a climate simulation mode. At least, in context of ENSO variability, the differences in ECMWF and NCEP heating anomalies
are small in comparison with CCM3's heating departures from either of these anomalies, allowing characterization of the CCM3's ENSO heating structure: horizontally, as a more
meridional redistribution ("Hadley-like"), and vertically, as a substantially "bottom-heavy" profile, relative to the reanalyses anomalies.
In a companion paper, deficiencies in the simulated ENSO surface winds are related to specific features of the CCM3's heating error, from diagnostic modeling.
Member publication : 2000
Member publication
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