The main goal of the GCSS Pacific Cross-section Intercomparison (GPCI) is to evaluate and improve the representation of tropical and sub-tropical cloud and precipitation processes in climate prediction models. In GPCI, a new type of model evaluation is proposed where climate models are analyzed along a Pacific Ocean transect from California to the equator. This approach aims at complementing the more traditional efforts in GCSS by providing a simple framework for the evaluation of models that encompasses several fundamental cloud regimes such as stratocumulus, shallow cumulus and deep cumulus, as well as the transitions between them.

Currently twenty four climate and weather prediction models are participating in GPCI. We will present results of the comparison between models and recent satellite data. In particular, we will explore in detail the potential of the Atmospheric Infrared Sounder (AIRS) and CloudSat in terms of the evaluation of the representation of the atmospheric hydrologic cycle in climate models. In addition we will discuss the utilization of high-resolution models to evaluate and improve the physics of climate models in the context of GPCI.