- Our participation in the AMIP exercise yielded a 10 year 1979-1988 integration with the 17-layer GLA GCM which in turn was derived from the earlier 9-layer version of the GLA GCM of Kalnay et al. (1983), but for several improvements on an ongoing basis. We discovered the following key features of the model.
- The model simulates a very stable rainfall climatology and surface hydrology that is characterized by realistic interannual variations in response to observationally prescribed sea-surface temperatures.
- The model also simulates a statistically discernible climate variation in the tropics together with a realistic large-scale response of the monsoon circulation forced by the 1987/1988 SST variations.
- Among the key outstanding features of the simulation are i) a respectable Koeppen Climate classification, ii) a realistic 30-60 day oscillation, 1995: and iii) a skillful response of the Indian and Asian monsoons to SSTs and presumably snow and ice. The key model deficiencies comprise the following:
- a. Too high land surface temperature particularly in the local summer
b. Excessive zonality of circulation at mid and high latitudes with weak eddy transports and low polar surface pressures.
c. Lack of skill in seasonal forecasts outside the tropics.
d. Several isolated generic deficiencies of all GCMs.