The South Pacific Convergence Zone (SPCZ) is a large region of cloud and rainfall extending across the South Pacific and influencing the climate of many Pacific Islands. The SPCZ position and intensity varies from year to year due to El Nino Southern Oscillation. Correctly forecasting the SPCZ is therefore important for improving seasonal rainfall forecasts in the South Pacific.

The researchers analysed the performance of the ACCESSS1 seasonal forecast model to predict the SPCZ position and rainfall over the period 1990-2012. ACCESSS1 performed better in simulating the SPCZ than the previous model, POAMA.

However, there are still challenges, including simulating extreme “zonal SPCZ” events which often occur during strong eastern Pacific El Nino events.

Paper: Beischer, T.A., Gregory, P., Dayal, K., Brown, J.R., Charles, A.N., Wang, W.D., Brown, J.N. Scope for predicting seasonal variation of the SPCZ with ACCESS-S1. Clim Dyn (2021).