Australian farmers are one step closer to having regionally-relevant climate forecasting products thanks to the findings of research into Australia's regional climate drivers.

The findings offer new insights into the relationship between large-scale climate drivers and rainfall patterns in Australia's major agricultural regions.

"Simply learning that the influence of the Indian Ocean Dipole is mainly confined to the second half of the calendar year and that it particularly affects the agricultural regions of southern Australia provides useful information for farm managers," says Dr Mike Pook from the Centre for Australian Weather and Climate Research, which carried out the research. The Centre is a partnership between CSIRO and the Bureau of Meteorology.

"If producers see the positive phase of the Indian Ocean Dipole developing, for example, then they know that finishing rain in southern Australia is unlikely to be as good as they might like it to be. This is an additional influence but it still has an effect."

The research also found that the effect of the Southern Annular Mode—a measure of the strength and extent of the westerly winds over the Southern Ocean—is clearly confined to the south-west of Western Australia in autumn and the south-west coast of Victoria and western Tasmania in winter.

Dr Pook believes producers who understand rainfall variability associated with the Southern Annular Mode can make better assessments for their businesses.

"Farmers further north in Western Australia need not get upset if the Southern Annular Mode is positive because it really only reduces rainfall at the very south-west of the wheat-growing region in Western Australia in autumn," he explains.

The one-year project was funded by Managing Climate Variability.

The research also aims to identify current knowledge gaps and develop a research roadmap for improving seasonal forecasting skill and reliability.

"What we really need to understand better are the mechanisms linking climate drivers with rainfall," says Dr Pook. "How do drivers such as El Niño or the Indian Ocean Dipole work through the atmosphere to affect seasonal rainfall?"

Dr Pook and his colleagues are already using the findings in a new project in Western Australia to help improve seasonal forecast models for the south-west of the state.