Simulation of Long-Term Changes of the Equilibrium Line Altitude in the Central Chilean Andes Mountains Derived From Atmospheric Variables During the 1958–2018 Period

Mass balance of White Glacier, Axel Heiberg Island, N.W.T., Canada, 1960–91

Journal of Glaciology ◽

10.1017/s0022143000003531 ◽

1996 ◽

Vol 42 (142) ◽

pp. 548-563 ◽

Cited By ~ 35

Author(s):

J.Graham Cogley ◽

W. P. Adams ◽

M. A. Ecclestone ◽

F. Jung-Rothenhäusler ◽

C. S. L. Ommanney

Keyword(s):

Mass Balance ◽

Satellite Images ◽

Equilibrium Line ◽

Glacier Mass Balance ◽

Equilibrium Line Altitude ◽

Fold Reduction ◽

Random Samples ◽

Measurements Errors ◽

Standard Techniques

AbstractWhite Glacier is a valley glacier at 79.5°N with an area of 38.7 km2. Its mass balance has been measured, over 32 years with a 3 year gap, by standard techniques using the stratigraphic system with a stake density of the order of one stake per km2. Errors in stake mass balance are about ±(200–250) mm, due largely to the local unrepresentativeness of measurements. Errors in the whole-glacier mass balanceBare of the same order as single-slake errors. However, the lag-1 autocorrelation in the time series ofBis effectively zero, so it consists of independent random samples, and the error in the long-term “balance normal”〈B〉is noticeably less.〈B〉is −100 ± 48 mm. The equilibrium-line altitude (ELA) averages 970 m. with a range of 470–1400 m. Mass balance is well correlated with ELA, but detailed modelling shows that the equilibrium line is undetectable on visible-band satellite images. A reduced network of a few stakes could give acceptable but less accurate estimates of the mass balance, as could estimates based on data from a weather station 120 km away. There is no evidence of a trend in the mass balance of White Glacier. To detect a climatologically plausible trend will require a ten-fold reduction of measurement error, a conclusion which may well apply to most estimates of mass balance based on similar stake densities.

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Mass balance of White Glacier, Axel Heiberg Island, N.W.T., Canada, 1960–91

Journal of Glaciology ◽

10.3189/s0022143000003531 ◽

1996 ◽

Vol 42 (142) ◽

pp. 548-563 ◽

Cited By ~ 1

Author(s):

J.Graham Cogley ◽

W. P. Adams ◽

M. A. Ecclestone ◽

F. Jung-Rothenhäusler ◽

C. S. L. Ommanney

Keyword(s):

Mass Balance ◽

Satellite Images ◽

Equilibrium Line ◽

Glacier Mass Balance ◽

Equilibrium Line Altitude ◽

Fold Reduction ◽

Random Samples ◽

Measurements Errors ◽

Standard Techniques

AbstractWhite Glacier is a valley glacier at 79.5°N with an area of 38.7 km2. Its mass balance has been measured, over 32 years with a 3 year gap, by standard techniques using the stratigraphic system with a stake density of the order of one stake per km2. Errors in stake mass balance are about ±(200–250) mm, due largely to the local unrepresentativeness of measurements. Errors in the whole-glacier mass balance B are of the same order as single-slake errors. However, the lag-1 autocorrelation in the time series of B is effectively zero, so it consists of independent random samples, and the error in the long-term “balance normal” 〈B〉 is noticeably less. 〈B〉 is −100 ± 48 mm. The equilibrium-line altitude (ELA) averages 970 m. with a range of 470–1400 m. Mass balance is well correlated with ELA, but detailed modelling shows that the equilibrium line is undetectable on visible-band satellite images. A reduced network of a few stakes could give acceptable but less accurate estimates of the mass balance, as could estimates based on data from a weather station 120 km away. There is no evidence of a trend in the mass balance of White Glacier. To detect a climatologically plausible trend will require a ten-fold reduction of measurement error, a conclusion which may well apply to most estimates of mass balance based on similar stake densities.

Download Full-text