Having a good understanding of what drives our climate from season to season and year to year is necessary for interpreting how seasonal forecasts are likely to impact your farm business. If you’re interested in finding out more about what influences your regions’ climate from season to season and year to year then read on…
So what are the drivers of our climate during wet seasons and droughts in your region? And how is the climate changing over time? How often do you get average rainfall? (Probably not as often as you’d like!) Do you know the key signals for when the season is about to turn? When is the best time to look at forecasts? How could probabilistic forecasts be used in your business? Australia's climate is incredibly variable and this variability is increasing with global average temperature on the rise.
Looking back over historical climate data for a region can reveal some interesting trends showing the influence of our climate drivers on seasonal and annual rainfall over preceding decades.
This section is under development. It will include maps and pie charts for a wide range of grain growing localities that will enable you to see if and how the years have panned out in the past in the GRDC south cropping region.
Here is an example of what we'll be preparing for a range of localities across South eastern Australia:
Bordertown Aug-Oct Rainfall in 32 El Nino years since 1881:
Bordertown Aug-Oct rainfall in 27/20 IOD+ years since 1881:
To find out more about how our key climate drivers and other influences impact our regions climate, both year to year and seasonally, visit the Bureau of Meteorology, (BOM) Australian Climate influences webpages.
Interested in finding out more about the key climate drivers for south eastern Australia? The following references might be useful.
The Queensland Govt system of ENSO phases: Stone, R. and Auliciems, A., 1992. SOI phase relationships with rainfall in eastern Australia. International J. Climatology, 12, 625-636. https://www.researchgate.net/publication/216644358_SOI_relationships_with_rainfall_in_eastern_Australia
The three phases of the El Niño–Southern Oscillation (ENSO), Bureau of Meteorology Website Link: http://www.bom.gov.au/climate/enso/history/ln-2010-12/three-phases-of-ENSO.shtml
The original IOD year classification paper: Meyers, G.A., P.C. McIntosh, L. Pigot and M.J. Pook, 2007. The years of El Nino, La Nina and interactions with the tropical Indian Ocean. J. Clim., 20, 2872-2880. https://journals.ametsoc.org/doi/full/10.1175/JCLI4152.1
Modified and updated by: Ummenhofer, C.C., Sen Gupta, A., Briggs, P.R., England, M.H., McIntosh, P.C., Meyers, G.A., Pook, M.J., Raupach, M.R., and Risbey, J., 2011. Indian and Pacific Ocean influences on Southeast Australian drought and soil moisture. Journal of Climate, 24, 1313-1336. http://web.maths.unsw.edu.au/~ccumm/Ummenhofer.etal_2011_SEA.pdf
SAM index methodology: Marshall, G. J., 2003. Trends in the Southern Annular Mode from observations and reanalyses. J. Clim., 16, 4134-4143. Link: http://journals.ametsoc.org/doi/pdf/10.1175/1520-0442%282003%29016%3C4134%3ATITSAM%3E2.0.CO%3B2
SAM data source: Link: http://www.antarctica.ac.uk/met/gjma/sam.html
The relationship between the decline of South Eastern Australia rainfall and the strengthening of the sub-tropical ridge. Timbal, B. and W. Drosdowsky, 2012. International Journal. of Climatology. Link: http://onlinelibrary.wiley.com/doi/10.1002/joc.3492/pdf
The following references have useful information about the interaction of all four climate drivers and their influences on Australia: