A SIMPLIFIED CLIMATE MODEL WITH COMBINED ATMOSPHERIC-HYDROLOGICAL PROCESSES

Global climate change can be reproduced in detail by using three-dimen sional general circulation models (GCMs). However, such complex models require super-computers and extensive hours of computational time for a single attempt at reproducing long term climate change. An alternat ive approach is to make simplifying assumptions that retain the essent ial physics for the desired simulation. Energy balance and radiative-c onvective models are examples of such models. The model in this study follows the simplified approach using physics-based climate processes as well as interactions between atmospheric and hydrological processes . The vertically and latitudinally averaged mean temperature and mean water vapour content between 30 degrees N-50 degrees N latitudes are c onsidered as atmospheric state variables while soil and sea temperatur es and water storage amount are considered for describing the behaviou r of the hydrological system. Temperatures in both the atmosphere and ground are calculated by a thermal energy equation that considers the physically-based processes of shortwave radiation, longwave radiation, sensible heat flux, and latent heat flux. precipitation and evaporati on processes transport moisture between the atmosphere and ground. In this study, the radiation parameterization of the simplified climate m odel is tested in the investigation of the various effects of global w arming due to doubling and quadrupling of CO2. Changes of temperature, soil water content, evaporation rate and precipitation rate are inves tigated by numerical experiments. The simplified climate model provide s acceptable simulation of climate change and holds promise for practi cal investigations such as the interactions of physical processes in t he evolution of drought phenomena.