What's the game plan for the coming season?
05 August 2016
Predicting the weather and playing AFL football have a lot in common, according to Agriculture Victoria Climate Specialist Graeme Anderson.
“It doesn’t matter how many times the ball gets down to your forward line, you still need the forwards to convert them to goals,” said Graeme, who spoke at the recent MLA-sponsored Border Beef Conference.
And so it is the case with seasonal forecasting. Australia’s oceans come into each season with either good or bad form, and then the weather events determine who gets lucky and who misses out.
“Our key climate drivers and oceans can point to an average or wetter than average spring, but the individual weather events are still needed to convert that moist air into rain that falls on your farm,” Graeme said.
“Presently, June-July-August – the key seasonal outlook for southern producers – is indicating an average or wetter than average spring thanks to the Indian Ocean Dipole kicking us more moisture this year.”
Graeme said challenge for producers is to better understand the latest physics on climate drivers and the seasonal forecasts for your region, and being better able to manage the increasing variability of our seasons.
“Whether we believe in climate change or not, the ocean and atmosphere couldn’t care less," he said.
“Managing for seasonal variability will only become more important to farming enterprises, so having short, medium and longer term strategies to deal with this variability sets us up well for the future.”
Pre-season training
While weather-watching is an important element of farming, Graeme encouraged producers to focus on the aspects of their business they can control.
“Agile farmers routinely set key decision trigger points for action and, as each season unfolds, they exert the discipline to act as needed,” he said.
Graeme said the four key climate drivers, (or Climatedogs as comically explained in the Agriculture Victoria Youtube video), that producers need to watch and understand are:
- ENSO – (El Nino/Southern Oscillation)
- IOD – (Indian Ocean Dipole)
- SAM – (Southern Annular Mode)
- STR – Sub-tropical Ridge
Graeme said ENSO is particularly useful to watch during June-August to see how things are setting up for spring rainfall, with the Southern Oscillation Index being a measure of the pressure difference between Darwin and Tahiti.
“In El Nino years, like 2015, the pressure was higher over the Darwin/Australia region and lower at Tahiti (SOI negative) which is not helpful for sending moisture our way,” he said.
“Some places in NSW got very handy rains last year thanks to some moisture from the Indian Ocean, but we missed that in much of Victoria.
“The IOD has a strong correlation with Victorian spring rainfall.
“When it is positive, it is in a drier phase and wetter springs are more likely when the IOD is negative, like it is now for the 2016 winter/spring.”
The SAM refers to belts of westerly winds that circulate around the Southern Ocean and can influence the strength of frontal activity and rain triggers that get to Victoria.
When SAM is positive, fronts travel further south towards the pole, which can lead to drier winters. In summer, SAM in a positive phase can help rainfall events along Victoria’s south-east coast, eastern Victoria and southern NSW.
The STR is a natural high pressure belt which can influence the location and strength of high pressure systems across southern Australia.
Graeme said, in the past 10 years, SAM and the STR have both been less helpful in creating cooler season rainfall, with some weather events slipping south more often and, each decade since the 1950s has become warmer.
“Seven of our past 10 springs have been 1-2°C warmer than average, effectively extending the summer season into spring and autumn. This can give us some bumpy springs for producers to manage,” he said.
More information:
Agriculture Victoria Climate Specialist Graeme Anderson T: 03 5226 4821 E: graeme.anderson@ecodev.vic.gov.au
Producers in south-eastern Australia can subscribe free for monthly updates on the seasonal drivers by emailing The.Break@ecodev.vic.gov.au
For a monthly, three-minute update on YouTube visit https://www.youtube.com/channel/UClDCIII7gRZhUs03opGqH1g
To view Climatedogs visit
