Solar energy into the atmospheric system will cascade down to smaller scale eddies of high-low pressure systems, and ultimately to the molecular dissipation processes. Analysis of energy levels and energy transfer among different scales of motion offers a fundamental understanding of the general circulation of the atmosphere. The operational weather prediction models and the state-of-the-art climate models must be formulated to correctly simulate the energy cascade in the wavenumber spectral domain based on the knowledge of the observational analysis.
The objective of present study is to conduct a sequence of diagnostic energetics analyses of climate model simulations to assess the basic performance of the model atmosphere with respect to the scale interaction and the energy redistribution in the wavenumber domain. Saltzman's spectral energetics diagnosis is carried out in this study for AMIP climate model simulations by the European Center for Medium Range Weather Forecasts (ECMWF), Japan Meteorological Agency (JMA), and Meteorological Research Institute (MRI) at Tsukuba Japan.
The energetics analysis results under the AMIP project are compared with the observed atmosphere analyzed by the major operational analysis centers of the ECMWF, JMA and National Meteorological Center (NMC). In addition, the results are compared with the similar spectral energetics diagnosis for a series of climate model simulations by the NCAR CCM2 in conjunction with the Model Evaluation Consortium for Climate Assessment (MECCA) project. Under the MECCA project, we have completed the energetics analyses of climate models with different horizontal resolutions of R15, T42, T63, and T106 to evaluate the climate model sensitivity to the resolution.
In general, the energetics characteristics of different operational
models (ECMWF, NMC, and JMA) are reasonably consistent with each other,
and the discrepancies are relatively small. In contrast, we find that the
AMIP model simulations show substantial differences in energetics characteristics
which are apparently different from the observed atmosphere. The different
energetics characteristics of the AMIP model simulations will be presented
in comparison with those observations and the MECCA analysis results.