Temporal analysis of stable water isotopic characteristics in the Murray Darling Basin

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dc.contributor.authorHenderson-Sellers, Aen_AU
dc.contributor.authorAirey, PLen_AU
dc.contributor.authorStone, DJMen_AU
dc.contributor.authorBradd, Jen_AU
dc.contributor.authorMcGuffie, Ken_AU
dc.date.accessioned2021-07-01T00:51:43Zen_AU
dc.date.available2021-07-01T00:51:43Zen_AU
dc.date.issued2004-10-24en_AU
dc.date.statistics2021-03-18en_AU
dc.description.abstract“Water shortages, especially in tropical countries, are the climate challenge for this century” [1]. The isotopic composition of water and carbon in e.g. ice cores, ground water and biomass has been recognized as relevant to hydro-climates on timescales from glacial [2] to extreme weather [3]. We present Australian stable water isotope (SWI) research capability and exploit it in novel ways in order to establish objective validation of and improvement in existing water resource models ultimately reducing uncertainty in predictions. The use of stable water isotopes in hydro-climate modelling is refined on three timescales for the Murray Darling Basin. Isotopes demonstrate that in semi-arid regions, groundwater recharge occurs when the rainfall intensities exceed a threshold suggesting improvement of aquifer predictions over tens to thousands of years using isotopic threshold estimates. A range of atmospheric global circulation models ’ simulations of key hydrological parameters over years to decades reveals poor results for the majority (13 in 20) and underlines the value of isotopic constraints on basin hydrology. Modelling minute to monthly isotope fluxes using land surface schemes and a steady state (phenomenological) model of river hydrology allows comparison of the partitions of precipitation between transpiration, run-off and ‘lake’ evaporation with isotope observations from June 2002 to January 2003. These results will have the greatest importance if combined to improve the dynamics of simulations of regional water cycles [4]. Three timescales have been used here to explore the role of stable water isotopes in refining climate and hydrological models of the Murray Darling Basin. Firstly, over tens to thousands of years, we have examined the processes leading to the effective recharge of groundwater. The isotope data clearly indicate that in the warm arid/semi-arid regions, in contrast to the behaviour in cool temperate zones, effective recharge only occurs when the rainfall intensities exceed a threshold value. Isotopic estimates of this recharge threshold rainfall intensity could be applied to predictions of future groundwater resources. Secondly, over years to decades, we have assessed the success of a range of atmospheric global circulation models in simulating key hydrological parameters over the AMIP II period including El Niño and La Niña forcing. The results are rather poor for the majority (13 out of 20) GCMs suggesting that further constraints on the basin’s hydrology, such as from isotopes, may be valuable. In our third approach, we have modelled minute to monthly isotope fluxes using (a) land surface schemes (LSSs) at particular grid points within the Murray Darling Basin and (b) a steady state (phenomenological) model of river hydrology. Model conservation, climatic variations and ‘plausibility’, all pre-requisites for good simulations, have been investigated here for the Murray Darling. Models’ partitions of precipitation between transpiration, run-off and ‘lake’ evaporation are compared with isotope observations from the Darling River between June 2002 and January 2003. We find that: (i) more work is needed on gross water fluxes first; (ii) simple isotopic models generate plausible values but more complex ones, as yet, do not; and (iii) isotopes have potential for evaluation of whether LSSs are (in)correctly recharging and accessing groundwater reservoirs and for evaluation of the partitioning of water into runoff cf. re-evaporation. Tests based around these concepts offer a novel addition to the traditional methods of validating climate models and their sub-components.en_AU
dc.identifier.booktitleBook of extended synopsesen_AU
dc.identifier.citationHenderson-Sellers, A., Airey, P., Stone, D., Bradd, J., & McGuffie, K. (2004). Temporal analysis of stable water isotopic characteristics in the Murray Darling Basin. Paper presented to International Conference on Isotopes in Environmental Studies – Aquatic Forum 2004 Monte-Carlo, Monaco 25–29 October 2004. (pp. 419-420). Book of extended synopses. Retrieved from https://inis.iaea.org/collection/NCLCollectionStore/_Public/36/003/36003223.pdf?r=1#page=5&zoom=auto,-15,800en_AU
dc.identifier.conferenceenddate29 October 2004en_AU
dc.identifier.conferencenameIsotopes in Environmental Studies Aquatic Forum 2004en_AU
dc.identifier.conferenceplaceMonacoen_AU
dc.identifier.conferencestartdate25 October 2004en_AU
dc.identifier.placeofpublicationVienna, Austriaen_AU
dc.identifier.urihttps://inis.iaea.org/collection/NCLCollectionStore/_Public/36/003/36003223.pdf?r=1#page=5&zoom=auto,-15,800en_AU
dc.identifier.urihttps://apo.ansto.gov.au/dspace/handle/10238/11016en_AU
dc.language.isoenen_AU
dc.publisherInternational Atomic Energy Agencyen_AU
dc.subjectStable isotopesen_AU
dc.subjectWateren_AU
dc.subjectNew South Walesen_AU
dc.subjectClimatic changeen_AU
dc.subjectAquifersen_AU
dc.subjectSouthern Oscillationen_AU
dc.subjectHydrologyen_AU
dc.subjectGroundwater rechargeen_AU
dc.subjectRainen_AU
dc.titleTemporal analysis of stable water isotopic characteristics in the Murray Darling Basinen_AU
dc.typeConference Abstracten_AU
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