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Conference proceeding
Centennial-scale variability of soil moisture in Eastern Australia
pp.1140-1146
23rd International Congress on Modelling and Simulation. Modelling and Simulation Society of Australia and New Zealand (National Convention Centre in Canberra, 01/12/2019 - 06/12/2019)
2019
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Abstract
Soil moisture is of critical importance to maintaining agricultural productivity and is used as an indicator of agricultural drought. Antecedent soil moisture conditions are also important in forecasting catchment runoff and water storage levels. In-situ measurements of soil moisture, however, are exceedingly sparse at a global scale compared to most other hydroclimatic variables, and the temporal coverage of most records is limited to 15–20 years at best. To overcome this, water balance models have been developed and applied to evaluate soil water availability at centennial-scales. These include the Australian Water Availability Project (AWAP) Waterdyn model, and the Australian Water Resource Assessment (AWRA-L) models; two of the major water balance models used in Australia. This study looks to extend on their validation and application using a unique in-situ soil moisture data set from the Scaling and Assimilation of Soil Moisture and Streamflow (SASMAS) project for the Krui and Merriwa River catchments in eastern NSW, Australia. The two catchments are predominantly grazed and can be considered representative of the wider East Coast of Australia. Modelled outputs were compared against catchment average in-situ data and validated using correlation analyses. Both models performed similarly across both catchments, with the AWAP upper and lower soil moisture layers returning correlation coefficients of 0.60–0.75, while the AWRA-L root zone layer returned correlation coefficients of 0.76–0.78. Following this, long term temporal trends in soil moisture anomalies from 1908–2015 were examined against trends in rainfall cumulative deviation. Soil moisture deficits and cumulative deviation of rainfall were well correlated from 1908–2015 (r = 0.79–0.84), as was shown by the response of soil moisture to major droughts across SE Australia. Across the entire timeseries, no significant trend could be found. Many studies exist that look at this issue in response to the recent Millennium Drought across the Murray Darling Basin, however, the East Coast of Australia is identified as its own separate climate entity. Understanding soil moisture trends in this understudied area, where agricultural, environmental and industrial water needs intersect is important. A key finding was that rainfall and soil moisture deficits were more severe during the WWII Drought than the Millennium Drought. This needs to be accounted for in drought management strategies.
Details
- Title
- Centennial-scale variability of soil moisture in Eastern Australia
- Creators
- Abe Gibson - University of Newcastle AustraliaG.R Hancock - University of Newcastle AustraliaD.C Verdon-Kidd - University of Newcastle AustraliaT Wells - University of Newcastle Australia
- Contributors
- S Elsawah (Editor)
- Publication Details
- pp.1140-1146
- Conference
- 23rd International Congress on Modelling and Simulation. Modelling and Simulation Society of Australia and New Zealand (National Convention Centre in Canberra, 01/12/2019 - 06/12/2019)
- Publisher
- Modelling & Simulation Society of Australia & New Zealand; Australia
- Identifiers
- 991012995498202368
- Copyright
- These proceedings are licensed under the terms of the Creative Commons Attribution 4.0 International CC BY License (http://creativecommons.org/licenses/by/4.0), which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you attribute MSSANZ and the original author(s) and source, provide a link to the Creative Commons licence and indicate if changes were made. Images or other third party material are included in this licence, unless otherwise indicated in a credit line to the material.
- Academic Unit
- Faculty of Science and Engineering
- Language
- English
- Resource Type
- Conference proceeding