Oral Presentation AMOS Annual Meeting and International Conference on Tropical Meteorology and Oceanography

Synoptic climatology of the southern Indian Ocean (#44)

Danielle Udy 1 2 , Tessa Vance 3 , Anthony Kiem 4 , Mark Curran 5 , Neil Holbrook 1 2 , Carly Tozer 6 , James Risbey 6
  1. Institute for Marine and Antarctic Studies, UTAS, Hobart, TAS, Australia
  2. Centre of Excellence for Climate Extremes, Sydney, NSW, Australia
  3. Antarctic Climate and Ecosystems CRC, Hobart, TAS, Australia
  4. School of Environmental and Earth Sciences, University of Newcastle, Newcastle, NSW, Australia
  5. Australian Antarctic Division, Kingston, TAS, Australia
  6. CSIRO Oceans and Atmosphere, Hobart, TAS, Australia

Interpretation of eastern Antarctic ice core proxy climate records can be improved through better understanding of the climate dynamics and variability of the Southern Indian Ocean over multiple time scales.   In the case of high-resolution (seasonal to annual) ice cores, this is especially important, as event-scale precipitation and redistribution of the snow at the surface can enhance or weaken links to regional climate processes.  Two high resolution ice cores in East Antarctica, Dome Summit South (DSS) on Law Dome and Mt Brown South (MBS) in Wilkes Land (a new record collected in early 2018), provide an opportunity to extend and broaden our understanding of Southern Indian Ocean climate dynamics and variability.  For example, climate proxies from DSS have been found to be correlated with annual rainfall variability in southwest Western Australia and parts of eastern Australia.  However, poor understanding of the climate dynamics and variability in the mid to high latitude regions of the Indian and Southern Ocean across all timescales (synoptic to centennial) impacts the interpretation of these long (> 1000 years), high-quality climate proxies.  Here we present initial results from a synoptic typing study (using ERA-Interim reanalysis between 1979-2018) for the Southern Ocean region between 40°E and 180°E – the ‘atmospheric catchment’ region for both DSS and MBS. The synoptic typing enables the examination of the important synoptic processes that may lead to the amplification or damping of climate signals in ice core climate proxies, together with an improved understanding of the relationships between large-scale climate teleconnections and seasonal to inter-annual climate characteristics (precipitation and temperature) at the ice core sites. Improved understanding and interpretation of ice core climate proxies, especially during atypical years, will enhance the application of ice core proxies for understanding, quantifying and managing the impacts of climate variability and change in the Southern Hemisphere.