The influence of climate drivers on the Australian snow season

Pepler, Acacia; Trewin, Blair; Ganter, Catherine

doi:10.22499/2.6502.002

Cited by 16 publications

(19 citation statements)

References 15 publications

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“…The snowpack in the Australian Alps exhibits high temporal variability (Bormann, Evans, & McCabe, 2014;Nicholls, 2005;Pepler, Trewin, & Ganter, 2015) and provides an example of an ecologically and economically important, yet warm and highly marginal, snow environment. Positioned at the warm end of the maritime category in the classification system of Sturm, Holmgren, and Liston (1995), it shares some physical characteristics with other warm snow regions such as the Mediterranean zones described by Fayad et al (2017) and López-Moreno, Gascoin, et al (2017).…”

Section: Study Locationmentioning

confidence: 99%

Spatial controls on the distribution and dynamics of a marginal snowpack in the Australian Alps

Bilish

Callow

McGrath

et al. 2019

Hydrological Processes

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Seasonal snowpacks in marginal snow environments are typically warm and nearly isothermal, exhibiting high inter‐ and intra‐annual variability. Measurements of snow depth and snow water equivalent were made across a small subalpine catchment in the Australian Alps over two snow seasons in order to investigate the extent and implications of snowpack spatial variability in this marginal setting. The distribution and dynamics of the snowpack were found to be influenced by upwind terrain, vegetation, solar radiation, and slope. The role of upwind vegetation was quantified using a novel parameter based on gridded vegetation height. The elevation range of the catchment was relatively modest (185 m), and elevation impacted distribution but not dynamics. Two characteristic features of marginal snowpack behaviour are presented. Firstly, the evolution of the snowpack is described in terms of a relatively unstable accumulation state and a highly stable ablation state, as revealed by temporal variations in the mean and standard deviation of snow water equivalent. Secondly, the validity of partitioning the snow season into distinct accumulation and ablation phases is shown to be compromised in such a setting. Snow at the most marginal locations may undergo complete melt several times during a season and, even where snow cover is more persistent, ablation processes begin to have an effect on the distribution of the snowpack early in the season. Our results are consistent with previous research showing that individual point measurements are unable to fully represent the variability in the snowpack across a catchment, and we show that recognising and addressing this variability are particularly important for studies in marginal snow environments.

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Section: Study Locationmentioning

confidence: 99%

Spatial controls on the distribution and dynamics of a marginal snowpack in the Australian Alps

Bilish

Callow

McGrath

et al. 2019

Hydrological Processes

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show abstract

“…At lower elevations and on some ablating aspects, the ephemeral class may be more applicable (Sanecki et al, ). Precipitation, snow conditions, and runoff exhibit very high inter‐ and intra‐annual variability (Chubb, Siems, & Manton, ; Nicholls, ; Pepler, Trewin, & Ganter, ; Theobald, McGowan, & Speirs, ), and, in a global context, the Australian snowpack can be considered highly marginal (Bormann et al, ).…”

Section: Study Settingmentioning

confidence: 99%

“…and intra-annual variability (Chubb, Siems, & Manton, 2011;Nicholls, 2005;Pepler, Trewin, & Ganter, 2015;Theobald, McGowan, & Speirs, 2016), and, in a global context, the Australian snowpack can be considered highly marginal (Bormann et al, 2014).…”

Section: Precipitation Snow Conditions and Runoff Exhibit Very Highmentioning

confidence: 99%

Energy balance and snowmelt drivers of a marginal subalpine snowpack

Bilish

McGowan

Callow

2018

Hydrological Processes

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Snowmelt from the seasonal snowpack in the Australian Alps is a significant source of water for irrigated agriculture, electricity generation, and environmental flows in the Murray–Darling Basin. Previous studies have reported negative decadal to multidecadal trends in maximum snow depth, snow season duration, and snow‐covered area. Here, we characterise the energy balance of this marginal maritime snowpack for the first time. Turbulent fluxes measured using the eddy covariance and bulk aerodynamic methods are compared; discrepancies are attributed to the differing assumptions of the methods and characteristics of the measurement site. We examine the variability of the individual energy balance components and the drivers of snowmelt, and we find that incoming longwave radiation is the dominant control on snowmelt, providing more than 80% of the total energy to the snowpack over the season. During a midwinter rain‐on‐snow event, the advected rain heat flux provided 8% of the daily total, with the incoming longwave flux still accounting for almost 80%. The ground heat flux contributes a small proportion of the seasonal total but increases in patchy or intermittent snow cover. Comparing these results with those of studies in other maritime locations, we find that the turbulent fluxes are likely to make a proportionally higher contribution to the energy balance due to the short Australian snow season, underpinning the sensitivity of this environment to climate variability and change. These results extend the limited body of knowledge on highly marginal snowpacks and may be relevant to other regions with no direct measurements of the energy balance.

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“…ENSO is a significant driver of precipitation variability in SEA with El Niño (La Niña) events associated with below (above) average precipitation [ Gallant et al , ; Brown et al , ] through changes in the occurrence of precipitation events [ Pui et al , ]. Impacts of El Niño (La Niña) events for SEA include increased risk of drought (flood), bushfire [ Gallant et al , ], decreased snow cover [ Pepler et al , ], and streamflow [ Chiew et al , ]. Historically, the winter half year has been the wettest season in the Snowy Mountains; however, there is evidence that this may be changing [ Theobald et al , ].…”

Section: Introductionmentioning

confidence: 99%

Evidence of increased tropical moisture in southeast Australian alpine precipitation during ENSO

Theobald

McGowan

2016

Geophysical Research Letters

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An understanding of past atmospheric variability during El Niño–Southern Oscillation (ENSO) events is critical for informing debate on current and future changes in precipitation in a warming world. Here we show that atmospheric moisture content over much of Australia during inflow‐generating precipitation days (≥10 mm d−1) associated with La Niña (El Niño) events has increased (decreased) over the period 1958–2015. This is most notable in tropical latitudes which are the source of moisture of most precipitation ≥ 10 mm in southeast Australia (SEA). These trends are consistent with climate model projections and increases in tropical sea surface temperatures since the 1950s. They confirm that enhanced tropical ocean forcing of interannual climate variability through ENSO due to global warming is changing the hydroclimate of midlatitudes and in‐turn will require major changes to water resource use and management.

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The influence of climate drivers on the Australian snow season

Cited by 16 publications

References 15 publications

Spatial controls on the distribution and dynamics of a marginal snowpack in the Australian Alps

Spatial controls on the distribution and dynamics of a marginal snowpack in the Australian Alps

Energy balance and snowmelt drivers of a marginal subalpine snowpack

Evidence of increased tropical moisture in southeast Australian alpine precipitation during ENSO

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