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

to estimate the effect of calving on sea-level rise. The calving of floating glaciers, of course, has noeffect on sea level, but most small glaciers have grounded termini.Glazovskiy (1995) has estimated the rate of calving for glaciers in the Russian Arctic. Brown etal (1982) compiled calving rates for the Alaskan coast. In 1999-2000 mass balance and ice motionmeasurements were carried out on Mendenhall Glacier (Juneau Ice Field, Alaska). Comparisons ofseveral topographic maps (first is in 1948) and surface profiles determined in 1995, 1999 and 2000 byairborne GPS-guided, laser-ranging elevation profiling system (described in Echelmeyer et al., 1996)have helped to calculate iceberg calving into the lake, which was 6.2% of surface melting value longtermperiod (1948-2000), and 5.7% in 1999-2000 (Motyka et al., 2001).Unpublished estimates of totalcalving for Patagonia and Tierra del Fuego have been communicated by P. Holmlund, and for Svalbardby J.-O. Hagen. Meier (unpublished) has made crude estimates of calving discharge for the CanadianArctic and for small glaciers around Greenland and Antarctica by estimating the width of calving frontsand individual calving rates based on analogous climatic regions. Cogley (unpublished) has compiled alist of known or potential calving glaciers, both tidewater and lacustrine, from World Glacier MonitoringService sources. A number of other measurements of individual glacier calving, of all types, have beenmade. IPCC-1995 (Warrick et al, 1996) combined the estimates of Glazovskiy, Brown, Holmlund,Hagen, and Meier, to suggest that iceberg discharge into the sea from small glaciers at the present timetotals between 52 and 80 km 3 yr -1 , but this is an untested and uncertain result.Internal accumulation and iceberg calving are components, which may partially compensate eachother due to their different signs. But this cannot be recommended as a solution to the problem becauseof the need to determine the components for any particular glacier as well as on regional and globalscales. In only a very few cases do the mass-balance data presented in Appendix 3 include internalaccumulation and iceberg calving; these cases are noted.2.2.1. Mass balance of an entire glacier.To determine an average value of variables of glacier regime many sites have to be installed overthe glacier surface in order to cover all possible ranges of changing parameters: elevation (the mostimportant parameter), aspect, different forms of relief. From the results of measurements on many sitesthe mass balance of entire glacier is calculated:b n= (1/S) [Σ(b n1s 1+ b n2s 2+…+ b njs j)] (3),30