Climate data and their characterisation for hydrological scenario modelling across northern Australia

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Li, Lingtao; Donohue, Randall; McVicar, Tim ORCID ID icon; Van Niel, Tom; Teng, Jin ORCID ID icon; Potter, Nick; Smith, Ian; Kirono, Dewi; Bathols, Janice; Cai, Wenju; Marvanek, Steve; Gallant, Simon; Chiew, Francis; Frost, Andrew


2009-06-27


Report


71 pp


This report describes the climate data for the three climate scenarios used for the hydrological modelling in the project. The three climate scenarios are historical climate, recent climate, and future climate. The climate scenarios have 77 years of daily climate data at 0.05° x 0.05° (~ 5 km x 5 km) resolution grid cells across northern Australia. This report documents the data sources and methods implemented to develop the three climate scenarios, being historical climate (Scenario A), recent climate (Scenario B), and future climate (Scenario C). It also provides key climate characteristics of the three scenarios that allow water resource managers to better understand the current and projected climate of the systems they manage. The historical climate scenario (Scenario A) is the baseline against which other scenarios are compared. Scenario A is a 77-year record of daily rainfall and evapotranspiration data from 1 September 1930 to 31 August 2007, and is based on the SILO database developed and maintained in real-time by the Queensland Climate Change Centre of Excellence. The recent climate scenario (Scenario B) is used to assess future water availability should the climate in the future prove to be similar to that of the most recent 11 years (i.e. 1 September 1996 to 31 August 2007).The future climate scenario (Scenario C) is used to assess a range of possible climate conditions around the year 2030. Forty-five future climate variants, each with 77 years of daily climate sequences, were used. The future climate variants came from scaling the historical climate data to represent ~2030 climate, based on analyses of 15 global climate models (GCMs) and three global warming scenarios from the Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change. The historical (77-year) mean annual rainfall for the entire project area is 850 mm/year. Rainfall is highest in northern near-coastal areas, with some isolated locations receiving a mean annual rainfall in excess of 3000 mm/year. The lowest rainfall occurs in the south of the project area, where mean annual rainfall is less than 350 mm/year. Over the entire area, 94 percent of the rainfall occurs in the wet season (November to April). The 77-year mean annual areal potential evapotranspiration averaged across the project area is 1954 mm/year, varying from 2116 mm/year in the south to 1584 mm/year in the north. As mean annual potential evapotranspiration is greater than mean annual rainfall over most of the project area, the project area is largely a water-limited landscape. Note, however, that there are pockets where rainfall is greater than potential evapotranspiration on a mean annual basis, so hydrologically are considered energy-limited. Intense rainfall in the wet season leads to significant river flows. Over the 77-year period rainfall trends are increasing, and this is primarily due to an increase in rainfall intensity, with the number of rain-days per year being fairly constant. The recent (11-year) mean annual rainfall for the project area is 1001 mm/year, 17.8 percent higher than the historical mean. The increases are seen primarily in the Timor Sea Drainage Division (the western part of the study area). Recent annual rainfall is similar to historical annual rainfall for much of the Gulf of Carpentaria Drainage Division and the northern portion of the North-East Coast Drainage Division. There is considerable uncertainty in the global warming projections and in the predictions of how global warming affects local rainfall, while simulations of potential evapotranspiration have less variance. In the wet season months, regional projections of rainfall vary by up to 100 mm/month. Over the whole project area, projected water-year rainfall varies between 758 and 873 mm/year compared to its historical average of 850 mm/year. Projected potential evapotranspiration ranges between 1920 and 1972 mm/year compared to a historical mean of 1954 mm/year. Unde


CSIRO


CSIRO


Surfacewater Hydrology


Accepted Version (pdf) (7.52MB)


https://doi.org/10.4225/08/584af30470d0a


© Copyright 2009 CSIRO. all rights reserved. This work is copyright. Apart from any use as permitted under the Copyright Act 1968, no part may be reproduced by any process without prior written permission from CSIRO.


CSIRO Water for a Healthy Country Flagship


EP113200


Client Report (Author)


English


ISSN 1835-095


Li, Lingtao; Donohue, Randall; McVicar, Tim; Van Niel, Tom; Teng, Jin; Potter, Nick; Smith, Ian; Kirono, Dewi; Bathols, Janice; Cai, Wenju; Marvanek, Steve; Gallant, Simon; Chiew, Francis; Frost, Andrew. Climate data and their characterisation for hydrological scenario modelling across northern Australia. CSIRO: CSIRO; 2009.https://doi.org/10.4225/08/584af30470d0a



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