These are the latest results of a CPC model being produced by Dr. Yan Xue. Forecasts of the tropical Pacific SST and sea level anomalies are presented here using a linear statistical model (Markov model). The Markov model is constructed in a reduced multivariate EOF space of observed sea surface temperature (SST) and sea level analysis using the methodology of Xue et al. 2000. The model is trained for the 1981-98 period.

The SST is the NCEP SST analysis (Reynolds and Smith 1994); the sea level is from the NCEP ocean analysis (Behringer et al. 1998). All the data are monthly values averaged in grid boxes of 6 degrees in longitude and 2 degrees in latitude, and cover the tropical Pacific region within 19 degrees of the equator.

The Markov model is built with three multivariate EOFs in which the anomalous fields of SST and sea level are equally weighted. The model contains 12 monthly transition matrices (Xue et al. 2000).

Figure 1 suggests that the current warm anomalies (0.3-0.6 degree) in the tropical western Pacific change little in the winter, but increase rapidly and spread to the eastern Pacific in late spring and summer.

Figure 2 suggests that the positive sea level anomalies in the western Pacific move little in the winter, but move to the eastern Pacific quickly in late spring and summer, indicating the coming of El Nino events.

The full suite of model results are updated monthly and are available on the internet at: Yan Xue's Markov model home page or at Tropical Pacific Climate Information and Prediction System