Methane simulations at Cape Grim to assess methane flux estimates for South East Australia

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dc.contributor.authorLoh, ZMen_AU
dc.contributor.authorLaw, RMen_AU
dc.contributor.authorCorbin, KDen_AU
dc.contributor.authorSteele, LPen_AU
dc.contributor.authorKrummel, PBen_AU
dc.contributor.authorFraser, PJen_AU
dc.contributor.authorZahorowski, Wen_AU
dc.date.accessioned2020-06-12T06:07:47Zen_AU
dc.date.available2020-06-12T06:07:47Zen_AU
dc.date.issued2011-11-15en_AU
dc.date.statistics2020-05-15en_AU
dc.description.abstractA transport model intercomparison for methane (TransCom-CH4) has been run involving twelve models (Patra et al., 2011). We contributed simulations using two climate models, CCAM and ACCESS. The CCAM simulations were nudged to NCEP analysed meteorology, which allows simulated atmospheric concentrations to be compared to observations on synoptic timescales. The ACCESS simulations were forced only with observed sea surface temperatures and are consequently not expected to match observed synoptic variations. The TransCom experiment involved simulating six CH4 tracers (with different prescribed fluxes) along with SF6, radon and methyl chloroform. We have analysed hourly model output for Cape Grim and find that the magnitude of the non-baseline signal differs, especially in winter, dependent on the CH4 flux scenario used. The magnitude of the non-baseline signal also varies between models, although these differences can be reconciled when methane is scaled by model-simulated radon concentration. Comparison with observed CH4, also scaled using radon, suggests that the CH4 flux scenario with little or no wetland emissions in winter matches the observations. The observations also indicate an apparent extra source of CH4 in October-November not seen in the model simulations. However this appears to be an artefact of this analysis method which assumes that radon emissions are known (and in this case constant in space and time). We have found that the discrepancy between model and observations in spring appears to be due to a poor simulation of radon, rather than CH4. Observed radon shows a larger seasonality than modelled radon, which suggests that temporal and spatial variations in radon flux need to be considered. It would also be helpful to understand why the simulated CCAM and ACCESS radon (and non-baseline CH4) concentrations differ in magnitude. Comparisons with Cape Grim output from the other participating TransCom-CH4 models may provide some insight.en_AU
dc.identifier.citationLoh, Z. M., Law, R. M., Corbin, K. D., Steele, L. P., Krummel, P. B., Fraser, P. J., & Zahorowski, W. (2011). Methane simulations at Cape Grim to assess methane flux estimates for South East Australia. Paper presented at the 5th CAWCR Annual workshop, Melbourne, Victoria, 15-16 November 2011.en_AU
dc.identifier.conferenceenddate16 November 2011en_AU
dc.identifier.conferencename5th CAWCR Annual Workshopen_AU
dc.identifier.conferenceplaceMelbourne, Victoriaen_AU
dc.identifier.conferencestartdate15 November 2011en_AU
dc.identifier.govdoc9524en_AU
dc.identifier.isbn9780643107250en_AU
dc.identifier.urihttps://www.cawcr.gov.au/technical-reports/CTR_044.pdfen_AU
dc.identifier.urihttp://apo.ansto.gov.au/dspace/handle/10238/9626en_AU
dc.language.isoenen_AU
dc.publisherCentre for Australian Weather and Climate Researchen_AU
dc.relation.ispartofseriesCAWCR technical report no. 44;en_AU
dc.subjectMethaneen_AU
dc.subjectSimulationen_AU
dc.subjectAustraliaen_AU
dc.subjectMeteorologyen_AU
dc.subjectEnvironmental transporten_AU
dc.subjectEcological concentrationen_AU
dc.subjectAmbient temperatureen_AU
dc.subjectRadonen_AU
dc.titleMethane simulations at Cape Grim to assess methane flux estimates for South East Australiaen_AU
dc.typeConference Abstracten_AU
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