Glacier Mass Balance and Regime: Data of Measurements and ...

70×10 3 km 2 of ice caps around the Antarctic ice sheet (Weidick and Morris, 1998). These ice caps andmountain glaciers are situated close to but separate from main ice sheet of Antarctic. The boundariesbetween them are not easy to determine. In many cases these ice caps are joined to ice shelves or majorice sheets by fast ice or by other ice shelves, e.g. Spartan Glacier in Alexandra Island, or Berkner Islandwhich is surrounded by the Ronne-Filchner ice shelves. The aggregate area of these local ice capsaround Antarctica may comprise from 70×10 3 km 2 to perhaps 5% of the entire area of the Antarctic IceSheet, or about 700×10 3 km 2 . Obviously these individual glaciers belong to a population of smallglaciers, not the major ice sheet.A special study is required to calculate more accurately the area and mass-balance state of theseice caps around the two ice sheets. Even the very low temperature ice caps and mountain glaciers inAntarctica may have had mass-balances different from the steady-state. Four years of mass-balancemeasurements in the middle 1970s on Spartan Glacier on Alexander Ice Cap show an average net massbalancevalue different from steady-state (−103 mm yr -1 ). Mass-balance measurements on Dry Valleyglaciers show a regime close to steady-state (see Appendix 1 and 3) but these glaciers are situated inmuch more colder and drier climate conditions than those closer to the ocean.It is also important to note that the area of "small" glaciers around the two ice sheets has to beconsidered as they may produce an additional contribution to sea-level change due to global warming.Thus it is difficult to calculate the glacier contribution to the global water-cycle and to sea level change;these polar glaciers are, most likely, the largest source of error.There are other regional uncertainties, for example, the North and South Patagonian Ice Fields.Different results have been published:Source North Ice Field South Ice Field Sum(IAHS/ICSI, 1989) 4,500 14,000 18,500(Aniya, 1988, 1992) 4,200 13,000 17,200There are also several other regions in South America where glacier area is not yet definedquantitatively (IAHS/ICSI, 1989, see also Table 1.1 of this paper). Meier and Bahr (1996) give a figureof 680×10 3 km 2 for the total area of "small" glaciers, which is used here. This, however, is probably aminimum estimate because: 1) Meier and Bahr used scaling from the existing World Glacier Inventory16