What is meant by glacial mass balance what are the basic inputs and outputs?

Mass balance is the total sum of all the accumulation (snow, ice, freezing rain) and melt or ice loss (from calving icebergs, melting, sublimation) across the entire glacier. If glaciers have a mass balance that is in equilibrium with climate, then the inputs are equal to the outputs.

Which determines the mass balance of a glacier quizlet?

What is mass balance? The difference between the amount of snow and ice accumulation on the glacier and the amount of snow and ice ablation (melting and sublimation) lost from the glacier.

Why is it important that glaciers remain high in mass?

Glaciers cover about 10% of Earth’s land surface. Since glacial mass is affected by long-term climatic changes, e.g., precipitation, mean temperature, and cloud cover, glacial mass changes are considered among the most sensitive indicators of climate change and are a major source of variations in sea level.

How do glaciologist measure glaciers?

In the glaciological method, a network of stakes and pits are placed on the glacier surface and used to measure the change in surface level while taking into account snow/firn/ice density.

What was the mass balance of glaciers in 2018?

Based on preliminary data, 2018 is likely to be the 30 th year in a row of mass loss of mountain glaciers worldwide. According to the State of the Climate in 2018, The cumulative mass balance from 1980 to 2018 is −21.7 m, the equivalent of cutting a 24-m [79-foot] thick slice off the top of the average glacier.

What happens when a glacier is out of equilibrium?

This includes 23 consecutive years of negative mass balances. A glacier with a sustained negative balance is out of equilibrium and will retreat, while one with a sustained positive balance is out of equilibrium and will advance. Glacier retreat results in the loss of the low elevation region of the glacier.

When is the net balance of the Glacier measured?

The net balance is then the sum of the observed winter balance (bw) normally measured in April or May and summer balance (bs) measured in September or early October. Annual balance is the mass balance measured between specific dates.

How are the accumulations and ablations of a Glacier measured?

Accumulations and ablation are generally measured by reference to stakes inserted to a known depth into the glacier, and fixed by freezing and packing in 3. The location is fixed with GPS. Automatic weather stations on the glacier surface are key to understanding energy fluxes on the glacier.