Monsoon GCM Intercomparison
In-Sik Kang and participants
Seoul National University and participating institutes
The ability of present GCMs in simulating the Asian Monsoon climate and its variability associated with the 1997-98 ENSO are evaluated based on the data from the CLIVAR/Asian-Australian Monsoon AGCM Intercomparison. Daily clim atological mean data from AMIP II and a set of 10 ensemble experiment data for September 1996 to August 1998 were obtained from 11 institutes including COLA, DNM, GEOS, GFDL, IAP, IITM, MRI, NCAR, NCEP, SNU, SUNY/GLA.
The current GCMs have a capability of simulating gross features of Asian monsoon climate and the global anomalies associated with 1997-98 El Nino such as rainfall anomalies over the tropical Pacific and the PNA pattern. However, regional features in Monsoon regions are not well reproduced by the models. Among them are the regional monsoon rainfall and its anomalies in Meiyu-Baiu region, the surface temperature and soil moisture in Asian-Australian continents, and the northward migrations of summer Monsoon onsets. In particular, the summer mean rainfall and the seasonal variability in the western Pacific are underestimated by many of the models, on the other hand, those in Indian region are overestimated in most of the models. There are large inter-model variations in various monsoon indices simulated for the 1997 El Nino summer. Also note that each model has its own characteristics in the tropical intraseasonal oscillation. Most of the models have difficulty in simulating the ISO with a reasonable degree of reality. However, the spatial change of ISO activity due to El Nino is well reproduced by the models.
