A regional analysis of Australian climate in relation to ENSO using the PRECIS regional climate model

Abstract

The El Nino-Southern Oscillation (ENSO) is a large climate disturbance located in the tropical Pacific Ocean. During major warm events, El Nino warming extends over much of the tropical Pacific having major effects over the Australia region. Pressure, wind, surface temperature and precipitation anomalies are associated with the warm and cold phases of ENSO. This project involves the data processing of simulations spanning the years 1960 to 1990 having different boundary conditions, and present/future simulation covering the period 1990 to 2020, run with the regional climate model (RCM) PRECIS. The study domain was centered over Australia using a horizontal resolution of 50 km grid cells. The meteorological parameters extracted from the model are the standard parameters which vary during an El Nino event. Time series were compared with measured monthly and annual data sets from monitoring stations, to reveal the effect of El Nino over different areas of the region. For regional analysis, time series over the whole Australian domain were compared to measured data from different data centres. Spatial plots over the whole region were compared with measured annual data sets from data centres for the parameters. Comparison of baseline simulations was carried out over the whole region. The distribution of modelled parameters and comparison with observed parameters was analysed statistically, revealing the model's validation. The overall strategy of this particular analysis is to carry out a regional analysis of the above mentioned anomalies for present and future decades, and hence try to identify how well PRECIS can capture correlations between the climate variables and ENSO.