Modelling isotopic fluxes of coastal and inland landscapes using ISOLSM in New South Wales, Australia

Continuous In-situ measurements of oxygen and hydrogen stable isotopes in water vapour were paired with eddy covariance and meteorological observations to provide in-depth understanding of land-atmosphere interactions and assess the performance of the stable isotope-enabled National Centre for Atmospheric Research (NCAR) Land Surface Model (ISOLSM) for two distinct localities. Stable water isotopes, eddy covariance and meteorological observations were conducted over two separate periods at the Lucas Heights (coastal) and Baldry (inland) sites within New South Wales, Australia respectively. In addition, soil water, plant water, ground water and precipitation were collected for oxygen and hydrogen stable isotopes analyses. Furthermore, ET was partitioned using isotopic mass balance approach where water vapour stable isotopes were measured within Perspex chambers placed over bare soil and vegetated plots three times a day (morning, midday and evening). These data were compared with model output from ISOLSM. The results showed that ISOLSM had the capacity of reproducing observed flux behaviour. However, due to the fact that advective processes dominating water vapour at the coastal site, there was not obvious agreement between observed and modelled isotopic fluxes at Lucas Heights. Our studies provide detailed intercomparisons of isotopic fluxes in coastal and inland landscapes.