Different sensitivities of snowpacks to warming in Mediterranean climate mountain areas

Abstract

In this study we quantified the sensitivity of snow to climate warming in selected mountain sites having a Mediterranean climate, including the Pyrenees in Spain and Andorra, the Sierra Nevada in Spain and California (USA), the Atlas in Morocco, and the Andes in Chile. Meteorological observations from high elevations were used to simulate the snow energy and mass balance (SEMB) and calculate its sensitivity to climate. Very different climate sensitivities were evident amongst the various sites. For example, reductions of 9%-19% and 6-28 days in the mean snow water equivalent (SWE) and snow duration, respectively, were found per°C increase. Simulated changes in precipitation (±20%) did not affect the sensitivities. The Andes and Atlas Mountains have a shallow and cold snowpack, and net radiation dominates the SEMB; and explains their relatively low sensitivity to climate warming. The Pyrenees and USA Sierra Nevada have a deeper and warmer snowpack, and sensible heat flux is more important in the SEMB; this explains the much greater sensitivities of these regions. Differences in sensitivity help explain why, in regions where climate models project relatively greater temperature increases and drier conditions by 2050 (such as the Spanish Sierra Nevada and the Moroccan Atlas Mountains), the decline in snow accumulation and duration is similar to other sites (such as the Pyrenees and the USA Sierra Nevada), where models project stable precipitation and more attenuated warming. The snowpack in the Andes (Chile) exhibited the lowest sensitivity to warming, and is expected to undergo only moderate change (a decrease of <12% in mean SWE, and a reduction of < 7 days in snow duration under RCP 4.5). Snow accumulation and duration in the other regions are projected to decrease substantially (a minimum of 40% in mean SWE and 15 days in snow duration) by 2050.

Energy balance and snowmelt drivers of a marginal subalpine snowpack

“…In the midwinter months, our sensible heat measurements were similar to those modelled by López‐Moreno et al () at a higher elevation in the U.S. Sierra Nevada but were somewhat smaller over the season as a whole as a result of the relatively cool spring and the shorter period with snow in the Australian Alps. Net latent heat loss was around a quarter of that in the Sierra Nevada, and less than at all of the locations studied by López‐Moreno et al Although evaporation/sublimation from the Pipers Creek snowpack was modest in 2016, it is expected to be greater in those years in which warm dry north‐westerly winds affect the region during the spring ablation period.…”

“…The shorter snow season therefore suggests that the relative importance of turbulent fluxes is greater in the Australian Alps than in many other maritime environments. As sensitivity to warming is proportional to the relative magnitude of sensible heat in the energy balance (López‐Moreno et al, ), this study provides a physical basis to the statement that the Australian snowpack is highly marginal and sensitive to climate change.…”

Snow Sublimation in Mountain Environments and Its Sensitivity to Forest Disturbance and Climate Warming

“…These relative humidity decreases were important for damping the simulated decreases in vapor pressure gradient between the snow and the atmosphere (Figure ). Given that recent work has highlighted the importance of sublimation fluxes to snowpack resiliency in arid and semi‐arid environments (Harpold & Brooks, ; López‐Moreno et al, ), this study evaluated the role of sublimation, in order to contextualize the integrated snowpack response to changing climate conditions.…”

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

“…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). These include high bulk densities and low vertical temperature gradients.…”