Regional Climate Modelling in South-east Australia

This project will use a regional climate model to assess the importance of various physical processes related to the surface water cycle. How they change in time and space, and what changes are likely under future climate change. The project will produce an ensemble of regional climate projections for all of Australia at 50km resolution and over south-east Australia at 10km resolution. These simulations will be used to understand important regional climate processes in the present climate as well as projecting changes that will occur in a future warmed climate. In particular, changes in precipitation intensity on sub-daily time-scales will be investigated over Australia and the Maritime continent. The regional climate model used is the Weather, Research and Forecasting (WRF) model which is supported by the National Center for Atmospheric Research in the USA, and optimized to run in highly parallel computing environments.

Principal investigator

Jason Evans
Magnifying glass

Area of science

Earth Sciences

Systems used

Magnus and Zeus

Applications used

Partner Institution: The University of NSW| Project Code: n81

The Challenge

This project will address several important related problems:

1. What is the best method to produce regional climate change projections that indicate the most likely future climate as well as the range of plausible future climates that must be considered in impacts and adaptation studies, while explicitly accounting for the level of model independence?

2. How will precipitation change at the sub-daily time scale due to climate change?

3. How do heatwaves develop and intensify, and how does this change across cities to produce the large spatial variability in heat often seen?

The Solution

The World Climate Research Programme (WCRP) is backing an international initiative called the COordinated Regional climate Downscaling EXperiment (CORDEX – The goal of the initiative is to provide regionally downscaled climate projections for most land regions of the globe, as a compliment to the global climate model projections performed within the fifth Coupled Model Intercomparison Project (CMIP5). CORDEX includes data from both dynamical and statistical downscaling. It is anticipated that the CORDEX dataset will provide a link to the impacts and adaptation community through its better resolution and regional focus. Participation in CORDEX is open and any researchers performing climate downscaling are encourage to engage with the initiative.
The model evaluation framework consists of RCM simulations performed using the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim re-analysis as “perfect boundary conditions”. These simulations will be evaluated through a set of regional benchmark statistics, against regional datasets, that are designed and assembled by regional diagnostic teams. The climate projection framework within CORDEX is based on the set of GCM simulations in support of the IPCC fifth Assessment Report, referred to as CMIP5. CORDEX will focus on the GCM experiments using emission scenarios known as RCP4.5 and RCP8.5 which represent a mid and a high-level emission scenario. GCM driven CORDEX simulations will span 1951 to 2100. Each RCM should perform these simulations for multiple GCMs.

The Outcome

This project will perform an ensemble of CORDEX simulations with the original addition of saving the maximum precipitation each day over durations ranging from 5 minutes to 1 hour. As well as contributing to a robust regional climate projection ensemble within the CORDEX framework, this additional information will allow, for the first time, direct assessment of projected changes in precipitation extremes across time scales from 5 minutes to multiple days which can be used to address hydrology engineering practice. They will also be examined for future changes in heatwaves.

List of Publications

Liu, D.L., B. Wang, J. Evans, F. Ji, C. Waters, I. Macadam, X. Yang
and K. Beyer (2018) Propagation of climate model biases to biophysical modelling can complicate assessments of climate change impact in agricultural systems. International Journal of Climatology, doi: 10.1002/joc.5820.

Clarke, H. and J.P. Evans (2018) Exploring the future change space
for fire weather in southeast Australia. Theoretical and Applied Climatology, doi: 10.1007/s00704-018-2507-4.

Li, J., C. Wasko, F. Johnson, J. Evans and A. Sharma (2018) Can
Regional Climate Modeling capture the observed changes in spatial organization of extreme storms at higher temperatures? Geophysical Research Letters, 45(9), 4475-4484, doi: 10.1029/2018GL077716.

Ji, F., J.P. Evans, A. Di Luca, N. Jiang, R. Olson, L. Fita, D. Argüeso,
L. T-C Chang, Y. Scorgie, M. Riley (2018) Projected Change in Characteristics of
Near Surface Temperature Inversions for Southeast Australia. Climate Dynamics, doi: 10.1007/s00382-018-4214-3.

Herold, N., M. Ekstrom, J. Kala, J. Goldie and J. Evans (2018)
Australian climate extremes in the 21st century according to a regional climate model ensemble: implications for health and agriculture. Weather and Climate Extremes, doi: 10.1016/j.wace.2018.01.001.

Evans, J.P., M. Kay, P. Abhnil and A. Pitman (2018) The resilience of
Australian wind energy to climate change. Environmental Research Letters, 13(2), 024014, doi: 10.1088/1748-9326/aaa632