- Title
- Centennial-scale variability of soil moisture in eastern Australia
- Creator
- Gibson, A. J.; Hancock, G. R.; Verdon-Kidd, D. C.; Wells, T.
- Relation
- 23rd International Congress on Modelling and Simulation (MODSIM2019). Proceedings of 23rd International Congress on Modelling and Simulation (MODSIM2019) (Canberra, ACT 01-06 December, 2019) p. 1140-1146
- Publisher Link
- http://dx.doi.org/10.36334/modsim.2019.k22.gibson
- Publisher
- Modelling and Simulation Society of Australia and New Zealand
- Resource Type
- conference paper
- Date
- 2019
- Description
- 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 MurrayDarling 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.
- Subject
- soil moisture; AWAP; AWRA-L; rainfall; agriculture; drought; SDG 2; SDG 8; Sustainable Development Goals
- Identifier
- http://hdl.handle.net/1959.13/1436048
- Identifier
- uon:39900
- Identifier
- ISBN:9780975840092
- Language
- eng
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