Abstract
Abstract. A simple diagnostic model has been used to identify the parameters that induce large errors in the simulation of tropical precipitation in atmospheric General Circulation models (GCM). The GCM that have been considered are those developed by the National Center for Environmental Prediction (NCEP), the National Center for Atmospheric Research (NCAR) and the Japanese Meteorological Agency (JMA). These models participated in the phase II of the Atmospheric Model Inter-comparison Project (AMIP II) and simulated the climate for the period 1979 to 1995. The root mean-square error in the simulation of precipitation in tropical continents was larger in NCEP and NCAR simulations than in the JMA simulation. The large error in the simulation of precipitation in NCEP was due to errors in the vertical profile of water vapour. The large error in precipitation in NCAR in North Africa was due to an error in net radiation (at the top of the atmosphere). The simple diagnostic model predicts that the moisture converge is a nonlinear function of integrated water vapour. The large error in the interannual variance of rainfall in NCEP over India has been shown to be due to this nonlinearity.Key words. Meteorology and atmospheric dynamics (precipitation; tropical meteorology; convective processes)
Highlights
During the past 25 years, sophisticated General Circulation Models (GCM) have been used to simulate the seasonal variation of rainfall in the tropics
A diagnostic model developed by Srinivasan (2001) has been used to identify the factors that contribute to errors in the simulation of tropical rainfall
We have used a simple diagnostic model for tropical precipitation to identify the factors that contribute to errors in the simulation of rainfall in tropical continents in Atmospheric General Circulation Models (GCM)
Summary
During the past 25 years, sophisticated General Circulation Models (GCM) have been used to simulate the seasonal variation of rainfall in the tropics. The rainfall pattern in the tropics simulated by 30 GCM that participated in the AMIP was compared by Gadgil and Sajjani (1998) They found that most of the models could simulate. Srinivasan (2001) has shown that the observed seasonal variation of precipitation in large tropical continents can be simulated using a simple diagnostic model that is based on energy and moisture balance in a vertical column of the atmosphere. This diagnostic model identifies four parameters that control the seasonal variation of rainfall.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
