A moisture transport and precipitation parameterization for energy balance climate models

Abstract

The spatial distribution of water in all its three phases is an important factor in determining the climate. The interactions among temperature, water vapor, infrared emission and solar radiation form a series of feedback mechanisms, which play a very important role in the climate system. In order to trace moisture flow through the climate system and examine its impact on climate, a parameterization for the computation of moisture transport and precipitation is developed, one that will eventually be incorporated into a coupled energy balance climate-thermodynamic sea ice model (the CCSI model). This parameterization is tested by comparing computed energy transports and precipitation rates with available observations and by evaluating its sensitivity to variations in the values of specified parameters. The results of these studies indicate that the moisture parameterization is somewhat sensitive to variations in wind speed, surface air temperature and moisture flux, while it is relatively insensitive to changes in relative humidity. In general this parameterization does a good job in simulating the seasonal cycle and latitudinal distribution of the wind speed, moisture transport and precipitation when compared to the observed data and general circulation model (GCM) results.