Search for: All records

Abstract. This paper contains a description of recent changes tothe formulation and numerical implementation of the Quasi-GeostrophicCoupled Model (Q-GCM), which constitute a major update of the previousversion of the model (Hogg et al., 2014). The Q-GCM model has been designedto provide an efficient numerical tool to study the dynamics of multi-scalemidlatitude air–sea interactions and their climatic impacts. The presentadditions/alterations were motivated by an inquiry into the dynamics ofmesoscale ocean–atmosphere coupling and, in particular, by an apparent lackof the Q-GCM atmosphere's sensitivity to mesoscale sea-surface temperature (SST)anomalies, even at high (mesoscale) atmospheric resolutions, contrary toample theoretical and observational evidence otherwise. Major modificationsaimed at alleviating this problem include an improved radiative-convectivescheme resulting in a more realistic model mean state and associated modelparameters; a new formulation of entrainment in the atmosphere, whichprompts more efficient communication between the atmospheric mixed layer andfree troposphere; and an addition of a temperature-dependent windcomponent in the atmospheric mixed layer and the resulting mesoscalefeedbacks. The most drastic change is, however, the inclusion of moistdynamics in the model, which may be key to midlatitude ocean–atmospherecoupling. Accordingly, this version of the model is to be referred to as theMQ-GCM model. Overall, the MQ-GCM model is shown to exhibit a rich spectrumof behaviors reminiscent of many of the observed properties of the Earth'sclimate system. It remains to be seen whether the added processes are ableto affect in fundamental ways the simulated dynamics of the midlatitudeocean–atmosphere system's coupled decadal variability.