Aiguo Dai National Center for Atmospheric Research, Boulder, CO
The diurnal cycle is one of the most prominent signals of the climate system. It provides an excellent testbed for evaluating the performance of various model physics in general circulation models. For example, the diurnal and semidiurnal surface pressure tides can be used to evaluate the model simulaitons of atmospheric solar absorption by water vapor and ozone, while diurnal cycles of precipitation and cloudiness can be used to evaluate the performance of moist convection schemes. Here we will present some observational data sets and analysis methods, and use them to evaluate the NCAR Community Climate System Model (CCSM) in terms of its ability to simulate the diurnal variability.