Extended Abstract (276K)10.3
Comparison of the Multi-Scale Modeling Framework and the NCAR CAM with observations along a Pacific Ocean transect
Thomas P. Ackerman, Pacific Northwest National Laboratory, Richland, WA; and S. J. Ghan, R. T. Marchand, M. Ovtchinnikov, and A. S. Koontz
The Multi-scale Modeling Framework (MMF; previously “superparameterization”) provides an alternative treatment of cloud processes in a global climate model through the use of embedded cloud resolving models. Simulations with this model using climatological sea surface temperatures suggest that the model improves some aspects of the global energy budget compared to simulations with the parent GCM. There have been few detailed examinations, however, of the MMF performance. In this study we take advantage of the methodology outlined by the European Cloud System Study project (EUROCS) to compare the MMF to data and results from conventional GCMs. The EUROCS Pacific ocean study (Siebesma et al., QJRMS, accepted) reports a comparison of energy and hydrologic variables along a transect stretching SSW from the California coast to approximately the equator. This transect samples across the Hadley circulation and includes regions of marine stratus, trade-wind stratocumulus and deep convection. Comparisons are carried out for the period of JJA 1998. We have run the MMF and the CAM 3.0 (the parent GCM with standard parameterizations) using observed sea surface temperature values for this period. We compare results from both models with satellite observations of top-of-atmosphere fluxes and column integrated quantities and with meteorological quantities from re-analysis products. These data allow us to evaluate the ability of the embedded cloud resolving models to reproduce the hydrologic properties of the atmosphere and the impact of improved cloud resolution on tropical circulation.
Session 10, Climate Modeling Studies 2 (parallel with Session 11)
Wednesday, 12 January 2005, 1:30 PM-5:30 PM
Previous paper Next paper
Recorded presentation