An important step toward improving radiative transfer codes in general circulation models (GCMs) is to thoroughly evaluate them either by comparison to measurements directly or by comparing them to other data-validated radiation models. The Rapid Radiative Transfer Model (RRTM) shortwave (SW) radiation model accurately reproduces direct beam fluxes from the Line-by-Line Radiative Transfer Model...

Forget, F.; Millour, E.; Madeleine, J.-B.; Colaitis, A.; Spiga, A.; Montabone, L.; Hourdin, F.; Lefe, F.; Montmessin, F.; Gonzz-Galindo, F.; López-Valverde, M. A.; Lewis, S. R.; Read, P.-L. and Mulholland, D. (2011). Back to the basics: improving the prediction of temperature, pressure and winds in the LMD general circulation model. In: Fourth International Workshop on the Mars Atmosphere: Mode...

Regional atmospheric models have matured in the past few years. They now find broad applications that range from process studies, reconstruction of recent and paleoclimates, simulation of pathways and deposition of anthropogenic matter, construction of plausible scenarios of future climate change, and regional weather analysis. The initial major problem-namely, the illposed boundary value probl...

Most state-of-the-art global climate models (GCMs) project an increase in atmospheric poleward energy transport with global warming; however, the amount of increase varies significantly from model to model. Using an energy balance model that diffuses moist static energy, it is shown that: (1) the increase in atmospheric moisture content causes most of the increase in transport, and (2) changes ...

[1] The currently available theoretical and observational evidence for a latitudinal structure of thermocline vertical diffusivity is synthesized and included in a state of the art coupled climate model. Compared to the standard background value of 0.1 cm s , the simulations with the latitudinal structure show only little change in the meridional overturning circulation or northward heat transp...

The Atlantic meridional overturning circulation (AMOC) carries large amounts of heat into the North Atlantic influencing climate regionally as well as globally. Palaeo-records and simulations with comprehensive climate models suggest that the positive salt-advection feedback may yield a threshold behaviour of the system. That is to say that beyond a certain amount of freshwater flux into the No...

The Eastern North Pacific Subtropical Mode Water (ESTMW) is a water mass of low potential vorticity (PV) and appears as a weak pycnostad or thermostad. Distinct from other subtropical mode waters, it forms in the absence of a deep winter mixed layer. The formation mechanism of this ESTMW is investigated using an ocean general circulation model that is forced by monthly climatological temperatur...

A method to initialize an ensemble, introduced by Evensen (Physica, D 77:108–129, 1994a; J Geophys Res 99(C5):10143–10162, 1994b; Ocean Dynamics 53:343–367, 2003), was applied to the Ocean General Circulation Model (OGCM) HYbrid Coordinate Ocean Model (HYCOM) for the Pacific Ocean. Taking advantage of the hybrid coordinates, an initial ensemble is created by first perturbing the layer interface...

Most of the Southern Ocean (SO) is marginally stably stratified and thus prone to enhanced convection and possibly bottom-water formation whenever the upper ocean is cooled or made more saline by ice formation. Sea ice modifies the heat and freshwater fluxes, which in turn constitute a critical surface condition in this sensitive region of intense vertical exchange. The authors investigate the ...