A steep mass balance gradient is typical for somewhere with little accumulation and ablation and is, therefore, less sensitive to climactic changes. The shallower, the more maritime… I believe. I study soils, but wanted to make sure I fully understood a concept. Net Mass Balance bn is a value per unit area for the entire surface of a glacier, correct?
Thus, if one wanted to compute a rough estimate of runoff, you then only need to multiply the bn by the glacial surface area. In long term, the climate of the Earth is going towards the next Ice Age. What is your opinion about prolongation of the current Interglacial Stage thanks to the human effact on the global climate?
The same is valid with the total ice volumes on the Earth. In such a scale, the currrent temperature increase is still in the range of the natural fluctuation.
See for example, the slide on p. How to calculate Mass change? Save my name, email, and website in this browser for the next time I comment.
This site uses Akismet to reduce spam. Learn how your comment data is processed. Glacier mass balance Measuring mass balance Mass balance gradients Mass balance through time Further reading References Comments Glacier mass balance The mass balance of a glacier is a concept critical to all theories of glacier flow and behaviour.
Glacier mass balance and atmospheric circulation. By NASA. From Wikimedia Commons. The accumulation zone for this glacier extends from the plateau downwards. The Glacier as a System. Inputs are largely from precipitation, and also from wind-blown snow and avalanches. The glacier loses mass ablates mainly by the processes of calving and surface and subaqueous melt.
In this simplified figure, processes of internal and basal accumulation are ommitted. See Cogley et al. Meltwater stream on Mendenhall Glacier, Alaska. From: Gillfoto, Wikimedia Commons. Equilibrium line altitudes in a hypothetical glacier.
Forgot password? Don't have an account? Sign in via your Institution. You could not be signed in, please check and try again. Sign in with your library card Please enter your library card number. Related Content Related Overviews glacier equilibrium line ablation firn See all related overviews in Oxford Reference ». Show Summary Details Overview accumulation zone. Glacier accumulation Glacier ablation Equilibrium line altitude Glaciers as a system Further reading References Comments.
A glacier is a pile of snow and ice. In cold regions either towards the poles or at high altitudes , more snow falls accumulates than melts ablates in the summer season. If the snowpack starts to remain over the summer months, it will gradually build up into a glacier over a period of years.
Small valley glacier. The key input to a glacier is precipitation. Further sources of accumulation can include wind-blown snow, avalanching and hoar frost. These inputs together make up the surface accumulation on a glacier. The Glacier as a System. Inputs are largely from precipitation, and also from wind-blown snow and avalanches.
The glacier loses mass ablates mainly by the processes of calving and surface and subaqueous melt. After Cogley et al. In general, glaciers receive more mass in their upper reaches and lose more mass in their lower reaches. The part of the glacier that receives more mass by accumulation than it loses by ablation is the accumulation zone.
Photo: Murray Foubister Wikimedia Commons. The equilibrium line or snowline , also called the firnline marks the boundary between the zones of accumulation and ablation. The position of the equilibrium line changes from year to year as a function of the balance between snow accumulation in the winter and snowmelt during the summer.
Cool summers promote glacial advance and warm summers promote glacial retreat [ 5 ]. If warmer summers promote glacial retreat, then overall climate warming over many decades and centuries causes the glacier to melt and retreat significantly. Since the global climate has been warming due to human burning of fossil fuels [ 6 ], this warming is likely causing the ice sheets to melt or lose mass at an increasing rate over years and decades rather than over centuries [ 7 ].
This means that as time goes on, the glaciers are melting faster and contributing more to rising sea-level than expected based on the previous history. When ice sheets start to melt, such as those in Antarctica and Greenland, their flow into the ocean speeds up eventually creating floating ice sheets. The edges of the glacier or its extension as floating ice break off in a process called calving.
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