# title
AN OVERVIEW OF COUPLED GCM BIASES IN THE TROPICS

# abstract
2016 World Scientific Publishing Co. Pte. Ltd. This article examines the performance of complex numerical climate models with respect to several aspects of mean tropical climate and its variability. While substantial progress has been made since the early days of climate modeling, many challenges remain. A problem common to most coupled ocean-Atmosphere general circulation models (GCMs) is the cold sea surface temperature (SST) bias in the tropics. Despite this cold SST bias GCMs tend to produce too much precipitation over the tropical oceans, particularly south of the equator. Due to the close link between convection and surface winds, the precipitation biases in GCMs are also accompanied by surface wind biases. Particularly on the equator this strongly affects the simulated ocean currents and vertical temperature stratification. Precipitation biases over land surfaces likely contribute to biases over the equatorial oceans through their influence on the Walker circulation. This influence is particularly strong for the Atlantic basin, where GCMs typically overpredict precipitation over tropical South America and underpredict it over tropical Africa. Despite cold SST biases over much of the tropical oceans, warm SST biases dominate in the southeastern tropical Pacific and Atlantic. These warm biases appear to be due to a combination of surface wind biases (both on the equator and locally), excessive shortwave solar radiation due to insufficient low-level cloud, and weak oceanic stratification reducing the cooling effect of upwelling. The failure to capture the equatorial thermocline (the sharp temperature gradient separating the deep ocean from the warm surface layer) is also an important error source in coupled GCMs..

# publicationVenue.label
World Scientific Series on Asia-Pacific Weather and Climate

# authorList[]
RICHTER, I., DOI, T., CHANG, P., XU, Z., KATAOKA, T., TOZUKA, T., ... DE SZOEKE, S. P.