Climate modeling

A number of current coupled ocean-atmosphere climate models predict that the overturning of the North Atlantic may decrease somewhat under a future warmer climate.While this is not a feature that coupled models deal with well, its direct impact on the ocean s sequestration of carbon would be to cause a significant decline in the carbon that is stored in the deep water. This is a positive feedback, as oceanic carbon uptake would decline. Flowever, the expansion of area populated by the productive cool water plankton, and the associated decline... 

What are the difficulties in the use of climate models to estimate effects of increased CO... 

The possibility that the climatic future might feature a change in frequency of weather extremes underscores the desirability for climate models capable of predicting the future spectrum of prevailing circulation patterns. Weather extremes such as drought or excessive cold are the products of certain persistent (blocking) planetary wave patterns. In fact, it is reasonable to assume that past climatic... 

Fig. 4-13 Calculated and observed annual wet deposition of sulfur in mgS/m per year. (Reprinted from "Atmospheric Environment," Volume 30, Feichter, J., Kjellstrom, E., Rodhe, H., Dentener, F., Lelieveld, and Roelofs, G.-J., Simulation of the tropospheric sulfur cycle in a global climate model, pp. 1693-1707, Copyright 1996, with permission from Elsevier Science.)...

Fig. 4-14 Schematic diagram showing the components of a global climate model (GCM). (Reprinted from Hartmann (1994), with permission from Academic Press.)...

The complexities of land surface response and runoff generation have also presented a major obstacle to global climate modelers. Hydrologic response is linked to several important climate feedbacks (see Section 6.4.2), so imtil the hydro-logic cycle, and in particular its land surface component, can be accurately represented, there is little hope for accurate assessments of global change. 

Dickinson, R. E. (1984). Modeling evapotranspiration for three-dimensional global climate models. Geo-physical Monographs Q. E. Hansen and T. Takahashi, eds.) 29,58-72. American Geophysical Union. 

Bonan, G. B. (1996b). The NCAR land surface model (LSM version 1.0) coupled to the NCAR community climate model, NCAR Tech. Note NCARTTN-429+STR, NCAR, Boulder, CO. 

Craig, S. G. and Holmen, K. J. (1998). Atmospheric CO2 simulated by the National Center for Atmospheric Research Community Climate Model. 2. 

Dickinson, R. E., Henderson-Sellers, A., Kennedy, P. J. and Wilson, M. F. (1986). Biosphere-Atmosphere Transfer Scheme (BATS) for the NCAR Community Climate Model, NCAR Tech. Note TN-275+STR, Nat. Cent, for Atmos. Res., Boulder, CO. 

Hack, J. J. (1994). Parameterization of moist convection in the National Center for Atmospheric Research community climate model (CCM2), /. Geophys. Res. 99, 5551-5568. 

Holtslag, A. A. M. and Boville, B. A. (1993). Local versus nonlocal boundary-layer diffusion in a global climate model, /. Clim. 6,1825-1842. 

Six, C., Fischer, A. and Walters, S. (1996). The seasonal cycle of atmospheric CO2 A study based on the NCAR Community Climate Model (CCM2), /. Geophys. Res. 101,15079-15097. 

While most climate models consider feedbacks as being dependent on temperature (usually Ts), there are many other dependent variables in the climate system that could be involved, for example solar irradiance at the ground or rainfall. However, it is customary to describe these mathematically as functions of Tg,... 

Fig. 1 Global mean surface temperature evolution during the last century (observed) and projected for the next century. Bars on the right show the possible range of temperature increases from different AOGCM, and also from Simple Climate Models (SCM) and Earth Models of Intermediate Complexity (EMIC). Figure taken from IPCC [1]...

Fig. 2 Relative changes (between 2080-2099 and present, 1980-1999) of annual surface runoff on the globe, from results of several climate models forced by emissions of scenario AIB. Dashed areas indicate that more than 90% of models agree with the sign of change. Taken from IPCC [1]...

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