Mountain Glaciers and Ice Caps (Outside Greenland)
M. Sharp1, G. Wolken2, M.-L. Geai1, D. Burgess3, J.G. Cogley4, A. Arendt5, B. Wouters6
1Department of Earth and Atmospheric Science, University of Alberta, Edmonton, AB, Canada
2Alaska Division of Geological and Geophysical Surveys, Fairbanks, AK, USA
3Geological Survey of Canada, Ottawa, ON, Canada
4Department of Geography, Trent University, Peterborough, ON, Canada
5Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK, USA
6School of Geographical Sciences, University of Bristol, Bristol, UK
November 27, 2013
- Annual climatic mass balance (Bclim) was negative at 21 of 24 glaciers monitored in 2010-2011.
- Regional mean Bclim (for all available glaciers in 2010-11) was the second most negative value, after 2009-10, in the period 1989-2011. The last time the regional mean Bclim was positive was in 1992-1993.
The area of mountain glaciers and ice caps in the Arctic exceeds 420,000 km2, representing about 54% of the total global and ice cover other than the ice sheets of Greenland and Antarctica. Between 2003 and 2009, wastage of these glaciers accounted for a net annual input of ~174 Gt a-1 of water to the oceans. This is about 67% of the total global glacial input of water to the oceans from non-ice sheet sources (Gardner et al. 2013). Transfer of water from glaciers to the oceans occurs by a combination of surface melt and runoff, iceberg calving, and submarine melting of the termini of glaciers that end in the ocean.
The climatic mass balance (Bclim, Cogley et al. 2011) of a glacier, defined as the difference between annual mass gain (from precipitation on the glacier) and annual mass loss (from meltwater runoff, sublimation and evaporation), is a widely used index of how glaciers respond to climate change and variability. It is measured annually at as many as 27 glaciers in the Arctic (Fig. 50): three in Alaska, four in the Canadian Arctic islands, nine in Iceland, four in Svalbard and seven in northern Scandinavia. Unfortunately, there are no current measurements of Bclim in the Russian Arctic. Measurements of Bclim refer to a mass balance year, a one-year period between the ends of two successive melt seasons. In the Arctic, measurements are typically made in spring, when both the winter balance for the current mass balance year and the summer balance for the previous mass balance year are determined. For this reason, the most recent measurements available relate to the 2010-2011 mass balance year, except for Arctic Canada, for which data for 2011-2012 are available.
Measurements of Bclim of these glaciers for the mass balance years 2009-2010, 2010-2011 (World Glacier Monitoring Service 2012, 2013), and 2011-2012 (for Arctic Canada only) are presented in Table 6. In 2010-2011 Bclim was negative (mass loss) for 21 of the 24 glaciers, and positive (mass gain) for only three (all outlets of the northern margin of Iceland's Vatnajökull ice cap). Relative to 2009-2010, Bclim was more negative in 2010-2011 in coastal southern Alaska, Arctic Canada, Svalbard, and northern Scandinavia, and less negative in interior Alaska and Iceland. For the 2011-2012 mass balance year, measurements of Bclim for three of the glaciers in Arctic Canada were less negative than in the previous year, while in one case (Melville South ice cap) they were slightly more negative.
(Record length, years)
(kg m-2 yr-1)
(kg m-2 yr-1)
(kg m-2 yr-1)
in Fig. 50
|Alaska||Wolverine (46)||-85 (30)||-1070 (11)||1|
|Lemon Creek (59)||-580 (26)||-720 (16)||3|
|Gulkana (46)||-1832 (3)||-1290 (7)||2|
|Arctic Canada||Devon Ice Cap (52)||-417 (5)||-683 (1)||-503 (4)||7|
|Meighen Ice Cap (53)||-387 (12)||-1310 (1)||-1118 (2)||5|
|Melville S. Ice Cap (50)||-939 (4)||-1339 (2)||-1556 (1)||4|
|White (50)||-188 (20)||-983 (1)||-951 (2)||6|
|Iceland||Langjökull S. Dome (16)||-3800 (1)||-1279 (9)||8|
|Hofsjökull E||-2830 (1)||9|
|Hofsjökull N||-2400 (1)||9|
|Hofsjökull SW||-3490 (1)||9|
|Köldukvislarjökull (19)||-2870 (1)||-754 (5)||14|
|Tungnaarjökull (21)||-3551 (1)||-1380 (8)||10|
|Dyngjujökull (14)||-1540 (1)||+377 (12)||13|
|Brúarjökull (19)||-1570 (1)||+515 (17)||12|
|Eyjabakkajökull (19)||-1750 (3)||+525 (19)||11|
|Svalbard||Midre Lovenbreen (44)||-200 (31)||-920 (2)||17|
|Austre Broggerbreen (45)||-440 (28)||-1004 (3)||16|
|Kongsvegen (25)||+130 (18)||-434 (5)||15|
|Hansbreen (23)||-14 (17)||-280 (14)||18|
|Norway||Engabreen (42)||-520 (9)||-910 (5)||20|
|Langfjordjøkulen (21)||-760 (12)||-1257 (8)||19|
|Sweden||Marmaglaciaren (22)||-500 (9)||-1450 (2)||21|
|Rabots Glaciar (30)||-1080 (7)||-2110 (1)||22|
|Riukojietna (25)||-960 (8)||-1080 (6)||23|
|Storglaciaren (67)||-690 (20)||-1060 (9)||24|
|Tarfalaglaciaren (17)||-1060 (5)||-1820 (2)||25|
Taking annual mean values for all available Arctic Bclim records over the period 1989-2011 (for which there are at least 20 records in each year), 2010-2011 had the second most negative mean Bclim after 2009-2010 (Fig. 51) (Wolken et al. 2013). The last year when the regional mean Bclim was positive was 1992-1993. On a regional basis, 2010-2011 was the most negative balance year in the 50-52 year-long records from three of the four measured glaciers in Arctic Canada, and the second most negative for the other one (Melville South Ice Cap). Balance year 2011-2012 was the most negative at Melville South Ice Cap, the second most negative at Meighen Ice Cap and White Glacier, and the fourth most negative at Devon Ice Cap. Four or five of the seven most negative balance years on record for this region have occurred since 2006-2007. This is a result of strong summer warming that began around 1987 and accelerated after 2005 (Gardner and Sharp 2007, Sharp et al. 2011). For the three Icelandic glaciers with positive mass balance, 2010-2011 was among the three most positive balance years in the 19-20 year long records. For all three glaciers in northern Svalbard, 2010-2011 was among the five most negative balance years in the 25 to 45 year long records. In northern Scandinavia, where record lengths range from 21-67 years, 2010-2011 was among the nine most negative balance years at all seven sites.
The total mass balance (Bclim plus mass losses by iceberg calving and marine melting) of all glaciers in the Gulf of Alaska region and Arctic Canada can be estimated using GRACE satellite gravimetry (Fig. 52, Wolken et al. 2013). For the 2011-2012 mass balance year the estimate for the Gulf of Alaska is +51.9 ± 16.3 Gt, while for Arctic Canada it is -106 ± 27 Gt. The latter value is very similar to the record low value of 2010-2011, a result that is consistent with field measurements of Bclim (Table 6), and provides further evidence of the growing importance of this region as a contributor to global sea level rise (Gardner et al. 2011). Unfortunately, field measurements from Alaska are not yet available to compare with the GRACE estimate, which was the most positive annual value for the region for any year since the launch of GRACE in 2003.
Variability in mean summer temperature accounts for much of the inter-annual variability in Bclim in cold, dry regions like the Canadian high Arctic (Braithwaite 2005). As a result Bclim in these regions is likely closely related to land surface temperature (LST) over ice in summer (Hall et al. 2006). Figure 53 shows moderate to large LST anomalies over glaciers and ice caps throughout the Arctic, particularly in summers 2011 and 2012 in the Canadian high Arctic (northern Ellesmere, Agassiz, Axel Heiberg, Prince of Wales), where Bclim was especially negative (Table 6) and GRACE data showed large mass losses (Fig. 52). In more maritime regions like Iceland and southern Alaska, variability in winter precipitation is also a factor.
Arendt, A., S. Luthcke, A. Gardner, S. O'Neel, D. Hill, G. Moholdt, and W. Abdalati, 2013: Analysis of a GRACE global mascon solution for Gulf of Alaska glaciers. J. Glaciol., 59, 913-924.
Braithwaite, R. J., 2005: Mass balance characteristics of Arctic glaciers, Ann. Glaciol., 42, 225-229.
Cogley, J. G., R. Hock, L. A. Rasmussen, A. A. Arendt, A. Bauder, R. J. Braithwaite, P. Jansson, G. Kaser, M. Möller, L. Nicholson, and M. Zemp, 2011: Glossary of Mass Balance and Related Terms, IHP-VII Tech. Doc. Hydrol. 86, IACS Contr. No 2, UNESCO-IHP, Paris.
Gardner, A. S., and M. Sharp, 2007: Influence of the Arctic Circumpolar Vortex on the Mass Balance of Canadian high Arctic Glaciers. J. Climate, 20, 4586-4598.
Gardner, A. S., G. Moholdt, B. Wouters, G. J. Wolken, D. O. Burgess, M. J. Sharp, J. G. Cogley, C. Braun, and C. Labine, 2011: Sharp acceleration of mass loss from Canadian Arctic Archipelago Glaciers and Ice Caps. Nature 473, 357-360.
Gardner, A. S., and 15 others, 2013: A reconciled estimate of glacier contributions to sea level rise: 2003-2009. Science, 340, 852-857.
Hall, D. K., R. S. Williams, Jr., K. A. Casey, N. E. DiGirolamo, and Z. Wan, 2006: Satellite-derived, melt-season surface temperature of the Greenland Ice Sheet (2000-2005) and its relationship to mass balance. Geophys. Res. Lett., 33, L11501, doi:10.1029/2006GL026444.
Luthcke, S. B., T. J. Sabaka, B. D. Loomis, A. A. Arendt, J. J. McCarthy, and J. Camp, 2013: Antarctica, Greenland and Gulf of Alaska land-ice evolution from an iterated GRACE global mascon solution. J. Glaciol., 59, 613-631.
Sharp, M., D. O. Burgess, J. G. Cogley, M. Ecclestone, C. Labine, and G. J. Wolken, 2011: Extreme melt on Canada's Arctic ice caps in the 21st century. Geophys. Res. Lett., 38, L11501, doi:10.1029/2011GL047381.
Sasgen, I., V. Klemann, and Z. Martinec, 2012: Towards the inversion of GRACE gravity fields for present-day ice-mass changes and glacial-isostatic adjustment in North America and Greenland. J. Geodyn. 59-60, 49-63.
Wolken. G., M. Sharp, M.-L. Geai, D. Burgess, A. Arendt, and B. Wouters, 2013: [Arctic]. Glaciers and ice caps (outside Greenland). [in "State of the Climate in 2012"]. Bull. Amer. Met. Soc. 94, S119-S121.
World Glacier Monitoring Service, 2012: Preliminary glacier mass balance data for 2009/2010. http://www.wgms.ch/mbb/sum10.html.
World Glacier Monitoring Service, 2013: Preliminary glacier mass balance data for 2010/2011. http://www.wgms.ch/mbb/sum11.html.
Wouters, B., and W. J. O. Schrama, 2007: Improved-accuracy-of-grace-gravity-solutions-through-empirical-orthogonal-function-filtering-of-spherical-harmonics. Geophys. Res. Lett. 34, L23711, doi: 10.1029/2007GL032098.