Using a range of tools to forecast a season break and understand climate variability factors was the focus of a farmers’ workshop at Orbost, Victoria, run by Agriculture Victoria in March.
AgVic’s climate specialist Graeme Anderson aimed to bring some science to the discussion about drought and climate variability; and likened forecasting to a football tipping competition.
It was no secret to attendees to hear that, in the previous 12 months, much of Australia had experienced drought conditions gauged from below average to lowest on record; while northern Queensland had experienced flooding rated as highest on record.
Mr Anderson recommended measuring subsoil moisture to gather data that aided decision-making, particularly planning around the possibility or not of a seasonal break and sowing pasture.
“If there’s no moisture, how do you manage farm production?” he said.
“Farmers want better forecasts, to improve their understanding of climate impacts and be able to manage seasonal risk factors.”
He also recommended using the electronic tools available to gather information about the season. Long-term rainfall records can help predict the probability of a likelihood of rain falling at a particular time.
“This might help with making decisions around sowing crop or managing for recovering pastures,” Mr Anderson said.
“But there’s plenty of big variability in the system.”
He recommended Australian CliMate, www.climateapp.net.au, a predictive tool that crunches data to predict the potential of a seasonal break. Using Bete Bolong as an example, he showed it was 73 per cent likely, of 88 years in 120, that a seasonal break of more than 25 mm of rain could fall between March 1 and April 30.
Mr Anderson also said it was apparent the timing and impact of seasons was changing; since 2000, climate measurements demonstrated the seasonal rainfall zones had shifted southerly across Australia (www.aegic.org.au).
“In a lot of records, it’s clear autumn is changing in a lot of places from what we’re expecting,” he said.
Influences of the Indian Ocean dipole, the ENSO — Pacific Ocean moisture source, the Southern Annular Mode, trade winds, moisture in the air, rising pressure systems and changing temperature, were all discussed. Many of these are explained in the Climate Kelpie videos, available at www.climatekelpie.com.au
Ultimately, rain is due to the availability of precipitable water in the atmosphere.
Overall, Mr Anderson recommends accessing multiple tools for weather forecasting and seasonal decision-making.
“Weather bureaus are using as many tools as possible, to see how many of those tools endorse each other. It’s like footy tipping,” he said.
“Farmers shouldn’t rely on one tool.”
Predictions should also be as local as possible. The weather records for Orbost, for example, showed minimum and maximum temperatures averaged 9.5 and 19.8°C, respectively. Spring averaged 19°C and summer averaged 24.4°C. That knowledge helped create decision-making around the type of pastures and crops to grow.
“It is different here [at Orbost] because of influences from the Indian Ocean Dipole. Farmers in the Shepparton area are experiencing shorter spring seasons and later autumn breaks. More of them are growing summer crops,” Mr Anderson said.
He recommended farmers use weather forecast tools provided by meteorologist Jane Bunn and forecaster Dale Grey, among others.
Farmers were encouraged to drive growth on-farm by embracing research from their industry organisations, investing in appropriate infrastructure and building their own knowledge about business management, new technology, biosecurity and trade potential for their products.