scholarly journals The geomorphological role of snow since the Little Ice Age in the Sierra de Ancares (NW Spain)

2018 ◽  
Vol 44 (1) ◽  
pp. 171 ◽  
Author(s):  
P. Carrera-Gómez ◽  
M. Valcárcel
Keyword(s):  
Snow Cover ◽  
Little Ice Age ◽  
Ice Age ◽  
Nw Spain ◽  
Seasonal Snow ◽  
Snow Precipitation ◽  
Prior Construction ◽  
Seasonal Snow Cover ◽  
Rapid Mass

On the Pico Cuiña cirque, Sierra de Ancares (León, Spain), the seasonal snow cover undergoes both slow and rapid mass displacements. Push associated with moving snow is responsible for an intense geomorphological activity, which is characterised by the plucking and transport of fragments of the bedrock, the abrasion of rock surfaces and the deposition of the mobilized material. Pronival ramparts are the most characteristic accumulation geoform created by pushing snow. Its study enabled us to verify the functionality of the nival processes and to prove the relative antiquity of some of them. The use of lichenometric techniques, based on the prior construction of a growth curve for lichens of the Rhizocarpon subgenus, has made possible to date sectors of the pronival ramparts. Lichenometric dates show a series of events of geomorphic activity of the snow cover fitting chronologically within the so-called Little Ice Age. It can be deduced from the observation of the current geomorphic dynamics of the snow cover that, although Little Ice Age temperature decrease might be important, particularly in the summer, the role of the variations in snow precipitation must be also taken into consideration.

Effect of seasonal snow cover on litter decomposition in alpine forest

2013 ◽  
Vol 37 (4) ◽  
pp. 296-305 ◽  
Author(s):  
Qi-Qian WU ◽  
Fu-Zhong WU ◽  
Wan-Qin YANG ◽  
Zhen-Feng XU ◽  
Wei HE ◽  
...  
Keyword(s):  
Snow Cover ◽  
Litter Decomposition ◽  
Seasonal Snow ◽  
Alpine Forest ◽  
Seasonal Snow Cover

Modelling the hypsometric seasonal snow cover using meteorological parameters

2014 ◽  
Vol 60 (1) ◽  
pp. 51-64 ◽  
Author(s):  
Snehmani ◽  
Anshuman Bhardwaj ◽  
Mritunjay Kumar Singh ◽  
R.D. Gupta ◽  
Pawan Kumar Joshi ◽  
...  
Keyword(s):  
Snow Cover ◽  
Meteorological Parameters ◽  
Seasonal Snow ◽  
Seasonal Snow Cover

scholarly journals Canadian snow and sea ice: assessment of snow, sea ice, and related climate processes in Canada's Earth system model and climate-prediction system

2018 ◽  
Vol 12 (4) ◽  
pp. 1137-1156 ◽  
Author(s):  
Paul J. Kushner ◽  
Lawrence R. Mudryk ◽  
William Merryfield ◽  
Jaison T. Ambadan ◽  
Aaron Berg ◽  
...  
Keyword(s):  
Sea Ice ◽  
Snow Cover ◽  
Climate Prediction ◽  
Earth System Model ◽  
System Model ◽  
Prediction System ◽  
Earth System ◽  
Seasonal Snow ◽  
Observational Uncertainty ◽  
Seasonal Snow Cover

Abstract. The Canadian Sea Ice and Snow Evolution (CanSISE) Network is a climate research network focused on developing and applying state-of-the-art observational data to advance dynamical prediction, projections, and understanding of seasonal snow cover and sea ice in Canada and the circumpolar Arctic. This study presents an assessment from the CanSISE Network of the ability of the second-generation Canadian Earth System Model (CanESM2) and the Canadian Seasonal to Interannual Prediction System (CanSIPS) to simulate and predict snow and sea ice from seasonal to multi-decadal timescales, with a focus on the Canadian sector. To account for observational uncertainty, model structural uncertainty, and internal climate variability, the analysis uses multi-source observations, multiple Earth system models (ESMs) in Phase 5 of the Coupled Model Intercomparison Project (CMIP5), and large initial-condition ensembles of CanESM2 and other models. It is found that the ability of the CanESM2 simulation to capture snow-related climate parameters, such as cold-region surface temperature and precipitation, lies within the range of currently available international models. Accounting for the considerable disagreement among satellite-era observational datasets on the distribution of snow water equivalent, CanESM2 has too much springtime snow mass over Canada, reflecting a broader northern hemispheric positive bias. Biases in seasonal snow cover extent are generally less pronounced. CanESM2 also exhibits retreat of springtime snow generally greater than observational estimates, after accounting for observational uncertainty and internal variability. Sea ice is biased low in the Canadian Arctic, which makes it difficult to assess the realism of long-term sea ice trends there. The strengths and weaknesses of the modelling system need to be understood as a practical tradeoff: the Canadian models are relatively inexpensive computationally because of their moderate resolution, thus enabling their use in operational seasonal prediction and for generating large ensembles of multidecadal simulations. Improvements in climate-prediction systems like CanSIPS rely not just on simulation quality but also on using novel observational constraints and the ready transfer of research to an operational setting. Improvements in seasonal forecasting practice arising from recent research include accurate initialization of snow and frozen soil, accounting for observational uncertainty in forecast verification, and sea ice thickness initialization using statistical predictors available in real time.

scholarly journals Sub-surface melting in a seasonal snow cover

1995 ◽  
Vol 41 (139) ◽  
pp. 474-482 ◽  
Author(s):  
Gary Koh ◽  
Rachel Jordan
Keyword(s):  
Surface Temperature ◽  
Snow Cover ◽  
Continuous Wave ◽  
Surface Melting ◽  
Balance Model ◽  
Fmcw Radar ◽  
Seasonal Snow ◽  
Wet Snow ◽  
Seasonal Snow Cover ◽  
Good Agreement

AbstractThe ability of solar radiation to penetrate into a snow cover combined with the low thermal conductivity of snow can lead to a sub-surface temperature maximum. This elevated sub-surface temperature allows a layer of wet snow to form below the surface even on days when the air temperature remains sub-freezing. A high-resolution frequency-modulated continuous wave (FMCW) radar has been used to detect the onset of sub-surface melting in a seasonal snow cover. The experimental observation of sub-surface melting is shown to be in good agreement with the predictions of a one-dimensional mass- and energy-balance model. The effects of varying snow characteristics and solar extinction parameters on the sub-surface melt characteristics are investigated using model simulations.

scholarly journals Simulated retreat of Jakobshavn Isbræ since the Little Ice Age controlled by geometry

2018 ◽  
Vol 12 (7) ◽  
pp. 2249-2266 ◽  
Author(s):  
Nadine Steiger ◽  
Kerim H. Nisancioglu ◽  
Henning Åkesson ◽  
Basile de Fleurian ◽  
Faezeh M. Nick
Keyword(s):  
Little Ice Age ◽  
Ice Age ◽  
Climate Forcing ◽  
Relative Role ◽  
Regional Warming ◽  
History Of ◽  
The Impact ◽  
Term Response

Abstract. Rapid retreat of Greenland's marine-terminating glaciers coincides with regional warming trends, which have broadly been used to explain these rapid changes. However, outlet glaciers within similar climate regimes experience widely contrasting retreat patterns, suggesting that the local fjord geometry could be an important additional factor. To assess the relative role of climate and fjord geometry, we use the retreat history of Jakobshavn Isbræ, West Greenland, since the Little Ice Age (LIA) maximum in 1850 as a baseline for the parameterization of a depth- and width-integrated ice flow model. The impact of fjord geometry is isolated by using a linearly increasing climate forcing since the LIA and testing a range of simplified geometries. We find that the total length of retreat is determined by external factors – such as hydrofracturing, submarine melt and buttressing by sea ice – whereas the retreat pattern is governed by the fjord geometry. Narrow and shallow areas provide pinning points and cause delayed but rapid retreat without additional climate warming, after decades of grounding line stability. We suggest that these geometric pinning points may be used to locate potential sites for moraine formation and to predict the long-term response of the glacier. As a consequence, to assess the impact of climate on the retreat history of a glacier, each system has to be analyzed with knowledge of its historic retreat and the local fjord geometry.

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