Drivers of precipitation stable oxygen isotope variability in an alpine setting, Snowy Mountains, Australia

Abstract

Natural archives that preserve a stable isotopic signature are routinely used to reconstruct palaeoenvironmental conditions. Isotopic values of precipitation are known to be influenced by factors such as the amount and type of precipitation, moisture pathway, landscape and terrain factors, and processes associated with precipitation formation and deposition. This study investigates oxygen isotopic variability using real-time rain and snow precipitation data from a moderate altitude (<2250 m above sea level), Southern Hemisphere alpine environment, where the causes of isotopic variability are largely unknown. Previous research at Global Network of Isotopes in Precipitation sites skewed toward rain precipitation, low-altitude, predominantly coastal locations identified amount effects as the dominant explanation of isotopic variability in southern Australia. This study based on within-and between-event real-time sampling finds that the origin of moisture and terrain effects are the dominant cause of isotopic variability in this alpine region, with little evidence of amount effects. Rainfall that originated from similar Southern Ocean latitudes showed a consistent (moderate) isotopic signature (δ ) were found also. These results have significant implications for understanding atmospheric drivers of isotopic variability from which oxygen isotope-based palaeoclimate reconstruction is informed in regions with complex topography and geographically diverse moisture pathways such as the Australian Alps.

A Synoptic Classification of Inflow-Generating Precipitation in the Snowy Mountains, Australia

“…In a similar way, event precipitation isotope analyses conducted by Callow et al (2014) identified significant synoptic-type variability in the isotopic signature of precipitation in the Snowy Mountains. The results of our study further support the dominance of moisture-source pathways in controlling isotopic variability in this region.…”

Spatial variability in the isotopic composition of water in small catchments and its effect on hydrograph separation

“…Many studies have investigated the spatial variability in the isotopic composition of precipitation at the mesoscale (100–1,000 km 2 ) and larger scale (up to the regional and continental scale). They typically found a large spatial variability in the isotopic composition of precipitation that could be explained by the orographic effect, the amount effect, sub‐cloud evaporation, moisture recycling, and differences in the vapor source (e.g., Bortolami, Ricci, Susella, & Zuppi, ; Pionke & De Walle, ; Ersek, Mix, & Clark, ; Crawford, Hughes, & Parkes, ; Callow, McGowan, Warren, & Speirs, ; Tekleab, Wenninger, & Uhlenbrook, ; Peng, Chen, Zhan, Lu, & Tong, ; Kong & Pang, ; Giustini, Brilli, & Patera, ; Delavau, Stadnyk, & Holmes, ; Krklec, Domínguez‐Villar, & Lojen, ). Studies on the isotopic composition of precipitation in small catchments (<10 km 2 ) exists as well (e.g., Gou et al, ; Qu et al, ) but very few of these studies report the observed spatial variability (or data).…”

A multimethod approach to inform epikarst drip discharge modelling: Implications for palaeo‐climate reconstruction

“…The Yarrangobilly limestone is a massive Silurian formation located in the subalpine area of the northern region of Kosciusko National Park, southeastern Australia (Figure ). The region may provide critical data to understand the palaeo‐climate of both southeastern Australia and the Southern Hemisphere, due to the location of the caves complex, which experiences precipitation sourced from southern mid‐latitudes to the tropics (Callow, McGowan, Warren, & Speirs, ; Theobald, McGowan, Speirs, & Callow, ). Despite this, there is very little published research conducted on the speleothems and associated hydrology of this region (see Markowska et al, ; Spate, Jennings, Ingle Smith, & James, ; Webb et al, ).…”