What is relation between mass balance and volume balance?

What is relation between mass balance and volume balance?
what we can  infer from mass balance ?
what we can infer from volume estimations?
Is both are required  to know the glacier health?
Is there any relation between glacier velocity, mass balance and volume?
Kindly explain me in simple terms.

Asked by Raaj

Hello Raaj,

Mass balance is the sum of all the inputs to a glacier system minus all the outputs – so all the snow, avalanches, wind-blown snow, minus all the surface meltwater runoff, iceberg calving, submarine melting on a marine-terminating glacier, and so on.

The glacier balance velocity is the velocity required for a glacier, which is in equilibrium with climate, to maintain a certain size with a given mass balance. All the accumulated snow must be moved down to the end of the glacier where it is ablated (melted).

I’m not sure what you mean by volume balance, but essentially, if the inputs equal the outputs, then the glacier will remain stable – neither advancing nor receding. If the inputs are greater, the glacier will advance. If the outputs are greater, the glacier will recede.

Mass balance is therefore an estimate of glacier health. A glacier with a negative mass balance will recede. The majority of glaciers in the world have a negative mass balance.