The frequency distribution of glacier area with surface altitude (elevation), generally presented as a hypsometric curve or table giving the area of the glacier within successive altitude intervals.
Descriptive of a quantity that has been averaged over part or all of the area of the glacier. The area-averaged mass balance is simply the specific mass balance of the region under consideration. The
adjective has sometimes been used to emphasize that the specific mass balance is that of the whole glacier and not of a 'specific' location. 'Mean specific mass balance' has been used in the same sense.
The ratio in percent of the ice cover area to the total sea area or some geographical area at a specific moment of time. This local may be global covering an area of the seas of the entire hemisphere
or some part of an ocean or a sea, for example such as Baffin Bay or the Barents Sea.
Extent in two spatial dimensions, always understood in mass-balance work (when the two dimensions are horizontal) to be map area, that is, the extent of the glacier or part thereof when the glacier ou
tline is projected onto the surface of an ellipsoid approximating the surface of the Earth or onto a planar (horizontal) approximation to that ellipsoid. In mass-balance studies, except for ice discharge and for the special case of frontal ablation, lengths such as layer thicknesses are always measured parallel to the vertical axis and not normal to the glacier surface. When calculating volumes within a specified outline, the area to be used is therefore the integral of ds (an element of projected area) and not the integral of sec ds, the so-called 'true' area (where is the slope of the glacier surface). The glacier area excludes nunataks but includes debris-covered parts of the glacier. However, delineating the glacier where it is debris-covered can be very difficult, because the debris may cover stagnant ice and there may be no objective way to distinguish between the debris-covered glacier and contiguous ice-cored moraine.