Australian climate benchmarking CORDEX-Australasia CORDEX-CMIP6 model evaluation rainfall regional climate models regional climate projections temperature
This study applies a benchmarking framework to assess a 34-member ensemble of regional climate models that have dynamically downscaled Coordinated Model Intercomparison Project (CMIP6) models over the Australasian region. Four modelling centres contributed regional climate models to this ensemble using three regional climate models (RCMs) and a total of five model configurations. The RCMs compared are the Conformal Cubic Atmospheric Model (CCAM), the Weather Research and Forecast (WRF) model and the Bureau Atmospheric Regional Projections for Australia (BARPA-R). Assessment is conducted over the Australian continent using a separation into four major climate zones over a 30-year historical climatological period (1985–2014). Rainfall and near-surface temperatures are compared against six benchmarks measuring mean state patterns, spatial and temporal variance, seasonal cycles, long-term trends and selected extreme indices. Benchmark thresholds are derived either from previous studies or comparison with the driving model ensemble. Major model biases vary between ensemble members and include dry biases in northern and southern Australia, winter wet biases and a persistent low bias in the winter diurnal temperature range across all the modelling centres. Daily variability at large length scales is comparable in the driving global climate model and downscaled regional climate model length scales, and long-term trends are largely determined by the driving global climate model. Overall, the ensemble was deemed to be fit for purpose for impact studies. Strengths and weaknesses of the systematic benchmarking framework used here are discussed.
Details
Title
Towards benchmarking the dynamically downscaled CMIP6 CORDEX-Australasia ensemble over Australia
Authors/Creators
Xiaoxuan Jiang
Emma Howard
Chun-Hsu Su
Rachael N. Isphording
Benjamin Ng
Sarah Chapman
Fei Ji
Michael Grose
Jozef Syktus
Ralph Trancoso
Marcus Thatcher
Sugata Narsey
Giovanni Di Virgilio
Jatin Kala - Murdoch University, Centre for Terrestrial Ecosystem Science and Sustainability
Publication Details
Journal of Southern Hemisphere Earth Systems Science, Vol.75(2), ES24050
Publisher
CSIRO Publishing on behalf of the Bureau of Meteorology.