A comparison of single column model simulations of summertime midlatitude continental convection

Abstract

Abstract. Eleven different single-column models (SCMs) and one cloud ensemble model (CEM) are driven by boundary conditions observed at the Atmospheric Radiation Measurement (ARM) program southern Great Plains site for a 17 day period during the summer of 1995. Comparison of the model simulations reveals common signatures identifiable as products of errors in the boundary conditions. Intermodel differences in the simulated temperature, humidity, cloud, precipitation, and radiative fluxes reflect differences in model resolution or physical parameterizations, although sensitive dependence on initial conditions can also contribute to intermodel differences. All models perform well at times but poorly at others. Although none of the SCM simulations stands out as superior to the others, the simulation by the CEM is in several respects in better agreement with the observations than the simulations by the SCMs. Nudging of the simulated temperature and humidity toward observations generally improves the simulated cloud and radiation fields as well as the simulated temperature and humidity but degrades the precipitation simulation for models with large temperature and humidity biases without nudging. Although some of the intermodel differences have not been explained, others have been identified as model problems that can be or have been corrected as a result of the comparison.

Potential impacts from biological aerosols on ensembles of continental clouds simulated numerically

“…RMS errors of temperature and vapour mixing ratio (not shown) are similar. The mean errors here are comparable to or less than those from other CSRM studies of convection at the Oklahoma ARM site displayed by Ghan et al (2000) and Xu et al (2002). Table 3 shows the predicted and observed radiative fluxes, averaged over the whole mesoscale domain and simulated period.…”

Intercomparison of model simulations of mixed‐phase clouds observed during the ARM Mixed‐Phase Arctic Cloud Experiment. II: Multilayer cloud

“…The model specifications for this intercomparison are similar to previous Atmospheric Radiation Measurement (ARM) intercomparison studies for the ARM Southern Great Plains site (Ghan et al, 2000;Xie et al, 2005;Xu et al, 2005), with participation from both singlecolumn models (SCMs, representing a single grid cell of a general-circulation or weather-prediction model), and cloud-resolving models (CRMs). The fairly large domain in the vertical dimension precluded the participation of higher-resolution large-eddy models, although these models did participate in Part I.…”

Influence of different convection parameterisations in a GCM

“…Intercomparisons of convection schemes in the past have mostly been accomplished with single column models (e.g. Ghan et al, 2000;Xie et al, 2002) and focused on specific conditions. According to Randall et al (1996) this has the advantage of limited amounts of data (for both models and observations) to be compared and an easier identification and separation of individual effects.…”