@pbett

Seasonal predictive skill of intraseasonal synoptic type variability over the Cape south coast of South Africa by making use of the Met Office Global Seasonal Forecast System 5

, , , and . Int. J. Climatol., (Aug 1, 2016)
DOI: 10.1002/joc.4830

Abstract

The skill in predicting intraseasonal characteristics of synoptic type occurrences at the seasonal time scale over the all-year rainfall region of South Africa (35°–33°S and 21°–27°E) is assessed by utilizing an ensemble of simulations performed using the GloSea5 coupled ocean–atmosphere model. Hindcasts of daily sea-level pressure fields of 14 austral spring September–October–November (SON) and summer December–January–February (DJF) seasons, initialized in August and November, respectively, are analysed. The skill assessment is achieved through the use of self-organizing maps. Deterministic and probabilistic assessment of synoptic type frequency forecasts indicate that intraseasonal circulation variability over the Cape south coast region is marginally predictable at seasonal time scales, more so during SON than DJF. In particular, the results obtained demonstrate that there is potential for the skillful seasonal prediction of the anomalous frequency of occurrence of high-impact rainfall events associated with cut-off lows within SON seasons.

Links and resources

Tags