A Comparison of Amazonian Climate Data with General Circulation Model Simulations

Abstract

Climate data from the Anglo?Brazilian Amazonian Climate Observation Study have been compared with the simulations of three general circulation models with prognostic cloud schemes. Monthly averages of net all-wave radiation, incoming solar radiation, net longwave radiation, and precipitation obtained from automatic weather stations sited in three areas of Amazonia are compared with the output from the unified model of the Hadley Centre for Climate Prediction and Research, the operational forecasting model of the European Centre for Medium-Range Weather Forecasts (ECMWF), and the model of the Laboratoire de Météorologie Dynamique (LMD). The performance of the models is much improved when compared to comparisons of observations with the output from earlier, less sophisticated models. However, the Hadley Centre and LMD models tend to overpredict net and solar radiation, and the ECMWF model underpredicts net and solar radiation at two of the sites, but performs very well in Manaus. It is shown that the errors are mainly linked to the amount of cloud cover produced by the models, but also to the incoming clear sky solar radiation.