Indian Ocean Climate Initiative Stage 3 (IOCI3) - Very High Resolution Modelling of Hot Spell Trends and Projections for South-West and North-West Western Australia
IOCI3, a climate research collaboration between CSIRO, the Bureau of Meteorology (BoM) and the Western Australian Government, produced maps of mean hot spell intensity, frequency and duration for the 1958-2010 period using estimates derived from statistical models. They also produced maps of trends in hot spell intensity, frequency and duration for... more this time period. In addition they provided maps of mean hot spell thresholds, intensity, frequency and duration for the 1981-2010 period using estimates derived from statistical models, and projections of these characteristics for the 2070-2099 period under the A2 greenhouse gas (GHG) emissions scenario (described in the IPCC Special Report on Emissions Scenarios [SRES]), as well as the difference between these two periods." Results are provided in the JPEG file format. less
Climate Change Processes
daily maximum temperature
SRES A2 scenario
south-west Western Australia
north-west Western Australia
Indian Ocean Climate Initiative
Generalized Linear Model
High quality station data as well as quarter-degree gridded (0.25°× 0.25° resolution) daily maximum temperature data from BoM Australian Water Availability Project (AWAP) were used to produce these results. Hot spell temperature thresholds were selected using statistical methods. Hot spell occurrence (frequency) was modelled by a Poisson process, hot spell intensity by a generalized Pareto distribution, and hot spell duration through a geometric distribution. The Generalized Linear Model framework was used to estimate the parameters in the model for hot spells. This method was applied to daily maximum temperature data simulated from the CSIRO Cubic Conformal Atmospheric Model (CCAM) for both the present-day and possible future climate under the SRES A2 GHG emissions scenario. The CCAM was nested in the CSIRO Mk3.0 Global Climate Model host for the SRES A2 scenario.
Caveats & limitations: The hot spell projections should be seen as initial estimates only, and they should not be used for making impact, vulnerability and risk assessments. They were made using only one climate model (CCAM); more work using an ensemble of global and regional climate model results is required to provide more robust projections of hot spells in Western Australia.
Extreme events are by definition rare, and analysis relies on partial (extreme) datasets (e.g., daily maximum temperatures higher 35 °C). In addition, estimating extremes necessitates extrapolating beyond such relatively small observed records. Consequently, the uncertainty associated with these projections of extremes is large, especially when extrapolating from a small dataset. To produce these projections we used AWAP data was used to overcome data shortages. However, the methods used to construct the AWAP dataset (interpolation) may smooth out some extreme values; this may lead to an underestimation of extremes in some cases. To these uncertainties are added the uncertainties inherent in the use of climate models.
CC Public Domain
Bureau of Meteorology (Australia), CSIRO (Australia), Western Australian State Government (Australia)
Li, Yun; Lau, Rex; Katz, Rick; Phatak, Aloke (2012): Indian Ocean Climate Initiative Stage 3 (IOCI3) - Very High Resolution Modelling of Hot Spell Trends and Projections for South-West and North-West Western Australia. v1. CSIRO. Data Collection.
All rights (including copyright) CSIRO Australia 2012.
The metadata and files (if any) are available to the public.
CLSD IOCI3 Theme 2 - C2006/4983
The set of projections for north-west Western Australia in this collection is one of a total of three sets produced under Project 2.4, Physical-Statistical Modelling of Extreme Events, which was part of IOCI3 Theme 2, Current and Future Climate of the North West Including Extreme Events. This Project advanced modelling techniques to develop multi-s... moreite models for rainfall and temperature extremes for application to present-day and projected climatic conditions. New statistical, physical ('dynamical') and physical-statistical methods were developed or applied. This included development of spatial maps of changes in extreme rainfall intensity for defined annual recurrence intervals and durations.
The set of projections for south-west Western Australia in this collection is one of two sets produced under Project 3.2: Climate Extremes: Potential Forecast Skill and Climate Change Scenarios, which was part of IOCI3 Theme 3, Very-high resolution climate change projections for the South west. This Project developed scenarios for intensity-frequency-duration characteristics of seasonal rainfall under climate change.
Indian Ocean Climate Initiative Stage 3 (IOCI3) Results
The Indian Ocean Climate Initiative Stage 3 (IOCI3), a climate research collaboration between CSIRO, BoM and the Western Australian Government, has produced climate projections for south-west and north-west WA. These include fine-scale (statistically downscaled) projections for rainfall and temperature (IOCI3 Projects 2.3 and 3.1); projections of e... morextreme rainfall, including rainfall contributions from tropical cyclones; and projections of hot spells (heat waves) (IOCI3 Projects 2.4 and 3.2). less