This article will give you a clear understanding of how the SAM affects Australian Farmers and the weather patterns that are associated the its interaction with other climate drivers.
Hello again, dear Aussie farmers! Beyond the popular El Nino and La Nina, there’s another vital player impacting our climate: SAM, or the Southern Annular Mode. Let’s dive into understanding SAM and how it can help you navigate the farming seasons.
Ever noticed the belt of high pressure encircling the globe in the subtropics? That’s the subtropical ridge. To its south, we find the roaring westerly winds, often named the roaring 40s and furious 50s. SAM reflects the unusual shifts of these winds north or south.
When these winds shift, they stir the pot! They can influence the weather systems around our southern hemisphere, which includes those bringing rains to southern Australia.
Similar to our previous friend, the IOD, SAM has three moods: positive, neutral, and negative. They usually last about two weeks, but sometimes they stick around longer.
Typically, the westerly winds sit atop southern Australia during winter. This invites cold fronts from the south, blessing us with regular winter rains. But if these winds wander towards Antarctica, we get fewer rains, a situation termed positive SAM. However, there’s a twist. A positive SAM can also lead to heavier rains on the East Coast.
In summer, things flip! If the winds venture north (a negative SAM), drier air blankets eastern Australia. However, a positive SAM means more moist winds along the east coast, which translates to a higher chance of rain.
In spring, SAM’s influence resembles a mild summer pattern for southern Australia. A negative phase can even hint at a potential heatwave. Come autumn, SAM’s influence on rainfall diminishes, but a negative SAM can usher in extreme heat in northern and central regions.
SAM’s moves are linked to these famous climate drivers. During El Ninos, SAM tends to lean negative, and during La Ninas, it leans positive. This only intensifies their effects, especially in summer.
Lately, there’s been a drift towards more positive SAM events, causing weather systems to shift south.
Grasping the nuances of SAM empowers you to anticipate seasonal outlooks better. With this knowledge, you can craft strategies tailored to your crops, ensuring fruitful harvests.
If the IOD and Enso forecast are predicting wetter or dryer than usual conditions, you can combat the financial burden of these risks with our Dry Season or Wet Harvest Weather Certificates. Just give us a call or watch our tutorials and we can show you how to become financially independent from these events.
SAM might not be as famous as El Nino or La Nina, but it’s crucial in the grand scheme of Australia’s climate. Keep tabs on its rhythms to stay ahead of the curve. For a deeper dive into SAM, head over to http://www.bom.gov.au/climate/sam/
Here’s to savvy farming, rain or shine!