Association between the Dynamics of Indian Ocean Subtropical High and Winter Time Precipitation and Stream Flow: A Case Study Over Acheron River Catchment, Victoria

Abstract

In this study, we explore the relationships between winter (May-August) Acheron River catchment (ARC), Victoria, Australia, rainfall and streamflow and winter Indian Ocean Subtropical High Pressure (IOSHPS) and Indian Ocean Subtropical High Longitude (IOSHLN) through correlation and regression analysis. Analysis is performed for the period of 1951-2011. It is found that the correlation of IOSHPS with winter ARC rainfall and streamflow are -0.46 and -0.33 respectively and IOSHLN are -0.54 and -0.57 are observed. Dynamics (zonal movements) of IOSHPS analysis showed that east-west shifts of IOSHPS are responsible for the variable amounts of rainfall receive in the ARC that resulted in variable streamflow. Regression analysis suggested IOSH indices describe 38% and 36% variability in rainfall (May-August) and streamflow (May-August) over ARC respectively further investigations showed that southern oscillation index (SOI) and El-Nino southern oscillation (ENSO) have weak association independently as well as combination with IOSHLN than IOSH indices over ARC winter rainfall and streamflow.