RESPONSE TO ATMOSPHERIC FORCING DURING EL NINO

V. I. Kuzin and V. M. Moiseev

Sensitivity of the Pacific Ocean circulation to the nonstationary atmospheric forcing is computed using the ICM&MG RAS numerical model. Prognostic experiments on the formation of a positive sea surface temperature (SST) anomaly in the eastern tropical Pacific during the 1982 El Nino were carried out. The duration of the experiments was two and a half years of the model time (from September 1981 to December 1983). Surface wind stress and ocean heat fluxes were taken from the European Center for Medium-Range Weather Forecast reanalysis. The satellite SST data for this period are used as control data. According to the computations, a positive SST anomaly forms at the beginning of 1982 in the western part due to trade-wind weakening in the central and the eastern parts of the tropical Pacific. It moves to the east at the thermocline level. By December 1982, warm waters reached the east coast of the ocean and came out at the surface, forming a warm zone. A warm-water zone with a similar shape and amplitude is found from the satellite data. This allows us to make some conclusions about a real model response to the nonstationary wind forcing.