In Australia, we’ve become so used to hearing the term “drought” that many people have become desensitised to it. As such, it can be difficult to comprehend the magnitude of the current rainfall deficiencies currently being experienced by farmers across areas of the country – particularly across northern NSW and southern Queensland where years of failed wet and storm seasons has yielded some of the lowest rainfall totals on record. More concerning is that many of these locations have very long rainfall records – some dating back over 140 years.
To demonstrate the extent of this drought we have gone through rainfall records in Stanthorpe, Moree, Armidale and St George – all of which are experiencing their driest first 8-months of the year on record, and some only receiving a fraction of their average rainfall so far. Many other locations are in the same position – but these sites have long-standing rainfall records pushing well into the 1800s which helps illustrate how significant the lack of rainfall is compared to previous years.
One of the significant culprits to our unusual rainfall patterns has been the unusual sea surface temperature patterns experienced. The positive IOD (Indian Ocean Dipole) due to relatively cooler water located in the eastern Indian Ocean has played a large role in recent rainfall deficiencies. However the elephant in the room has been the Pacific Ocean where last year the atmosphere effectively decoupled from the oceanic sea surface temperature patterns. This was amplified by the lack of a clear oceanic signal, with sea surface temperatures not fitting into the normally accepted El Nino, warm neutral, neutral, cool neutral or La Nina classifications.