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

Links Between Sea Surface Salinity and Australian Rainfall During ENSO/IOD Events (#2009)

Saurabh Rathore 1 2 , Nathan L. Bindoff 1 3 4 , Caroline C. Ummenhofer 4 5 , Helen E. Phillips 1 , Ming Feng 6
  1. Institute for Marine and Antarctic Studies, Battery Point, TASMANIA, Australia
  2. ARC Centre of Excellence For Climate System Science, University of New South Wales, Sydney, NSW, Australia
  3. ACE CRC, University of Tasmania, Hobart, Tasmania, Australia
  4. ARC Centre of Excellence for Climate Extremes, University of New South Wales, Sydney, NSW, Australia
  5. Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA
  6. CSIRO , Oceans and Atmosphere, Indian Ocean Marine Research Centre, Crawley, WA, Australia

Oceans are the major source of atmospheric moisture that results in precipitation over land. The moisture originating from the ocean leaves an imprint on sea surface salinity (SSS), which enables us to track the oceanic moisture source region for precipitation over land. This study demonstrates that SSS is a good indicator for locating the oceanic sources of moisture for Australian precipitation during different El Niño-Southern Oscillation/Indian Ocean dipole (ENSO/IOD) events. The moisture transport during ENSO/IOD events from ocean to land has been analysed using atmospheric moisture flux divergence. Composite maps of sea surface temperature (SST), SSS, moisture flux divergence and Australian precipitation, allows the diagnosis of oceanic signals in precipitation over land. As ENSO/IOD events evolve, a characteristic SSS signal also emerges, accompanied by moisture flux divergence and transport. Strong signatures of SSS in the Pacific and Indian Ocean occur during the peak seasons i.e. December-February for ENSO and September-November for IOD respectively. Our results suggest that changes in SSS occur prior to the peak of ENSO/IOD events. This raises the prospect that tracking of SSS can reveal the source of moisture for precipitation over Australia and could aid prediction of terrestrial rainfall.