The models are coupled without flux correction over the Tropics
(30S-30N).
At higher latitudes the forcing fields were prescribed. The coupled
system exhibits
a warm SST bias in the Tropics and a too far westward extending Pacific
cold tongue,
a common deficiency of many state of the art coupled GCMs.
The cause of the cold tongue problem is mainly the due to stronger
and too
far westward extending easterly surface winds along the equator.
The atmospheric model's 850 mbar winds, however, compare well
with observational extimates from reanalyses commanding a better atmospheric
boundary layer formulation. The slight equatorial cold bias of the ocean
model reenforces this model deficiency.
Incorporating the stability effect into our atmopheric flux calculation and tuning the models surface wind estimates was crucial for obtaining a reasonable climatology of the coupled system.
We are still working on a better atmospheric boundary layer formulation and on analyzing the SST cold bias of the oceanic component. The various annual mean surface fluxes of the coupled system compare reasonably well with the observational estimates by Large et al. 1997.
The indian summer monsoon winds are underestimated which lead to warm SST bias along the eastern African coast and to increased precipitation over central Africa. The coupled system will be used to study and analyze the oceanic and atmospheric branches of the observed teleconnections of ocean SST anomalies with the PACS region.