Forecasting rainfall based on the Southern Oscillation Index phases at longer lead-times in Australia
Forecasting rainfall based on the Southern Oscillation Index phases at longer lead-times in Australia Journal Article
The Rangeland Journal
- Author(s): Cobon, David H., Toombs, Nathan R.
- Published: 2013
- Volume: 35
Abstract: Under the extensive grazing conditions experienced in Australia, pastoralists would benefit from a long lead-time seasonal forecast issued for the austral warm season (November–March). Currently operational forecasts are issued publicly for rolling 3-month periods at lead-times of 0 or 1 month, usually without an indication of forecast quality. The short lag between the predictor and predictand limits use of forecasts because pastoralists operating large properties have insufficient time to implement key management decisions. The ability to forecast rainfall based on the Southern Oscillation Index (SOI) phase system was examined at 0–5-month lead-times for Australian rainfall. The SOI phase system provided a shift of adequate magnitude in the rainfall probabilities (–40 to +30%) and forecast quality for the 5-month austral warm season at lead-times >0 months. When data used to build the forecast system were used in verification, >20% of locations had a significant linear error in probability space (LEPS) and Kruskal–Wallis (KW) test for lead-times of 0–2 months. The majority of locations showing forecast quality were in northern Australia (north of 25°S), predominately in north-eastern Australia (north of 25°S, east of 140°E). Pastoralists in these areas can now apply key management decisions with more confidence up to 2 months before the November–March period. Useful lead-times of ≥3 months were not found.
- Urls: http://www.publish.csiro.au/?act=view_file&file_id=RJ12105.pdf Available from, http://www.publish.csiro.au/paper/RJ12105 Download site
- Keywords: El Nino Southern Oscillation, forecast quality, hindcasting, Inter-decadal Pacific Oscillation, pastoralists.