Long-term Mass-balance Measurements Research Articles

Volume measurements of Mittivakkat Gletscher, southeast Greenland

AbstractHere we present ground-penetrating radar measurements of Mittivakkat Gletscher, southeast Greenland, to estimate an empirical volume–area scaling relationship at an individual glacier. Between a previous direct volume survey in 1994 and one in 2012, the glacier volume has decreased from 2.02 km3 to 1.44 km3 while the study area has decreased from 17.6 km2 to 15.8 km2. These results are in accordance with the cumulative mass loss observed by long-term mass-balance measurements (1995/96–2011/12) at Mittivakkat Gletscher and confirm that the glacier is in severe climatic disequilibrium (AAR = 0.17). The observed scaling exponent γ = 3.14 and coefficient c = 0.00025 km3–2γ are outside the range of global scaling parameters but sensitive to small uncertainties. Nevertheless, existing global volume-area scaling relationships estimate the volume of Mittivakkat Gletscher within 31% and 15% of the measured 1994 and 2011 volumes, respectively.

Mass Balance of Mountain and Subpolar Glaciers: A New Global Assessment for 1961–1990

The goals of this article are (1) to combine published and unpublished mass balance measured data on more than 200 glaciers, check the quality of the data, digitize, and compile these for the period from the end of World War II (1945) to 1993 (with emphasis on the 1961–1990 period), and (2) to perform a review and analysis of this compilation. A simple global average mass balance for this period is −164 mm yr−1 (totaling −4.9 m) in water equivalent, not including iceberg calving.There are only about 40 glaciers with continuous mass balance measurements for more than 20 yr, but more than 100 with 1 to 5 yr of mass balance records. The glaciers under mass balance study differ in size from very small mountain cirque glaciers (less than 1 km2) to large valley glaciers (several hundred square kilometers) and subpolar ice caps with an area of several thousand square kilometers. Continuous and long-term mass balance measurements have been carried out mostly on middle-size glaciers with several exceptions. There are no long-term mass balance measurements in the following size classes: from 2−6 to 2−3 km2; 28 to 210; and above 212 km2. The area of these unmeasured size classes of glaciers is about 200 × 103 km2, or about 29% of the global glacier area. The glacier area of mountain and subpolar glaciers (including local glaciers around Greenland and Antarctica ice sheets) is taken to be about 680 × 103 km2. The reduction in global glacier area due to retreat is calculated as 6–8 × 103 km2 from 1961–1990.

Mass Balance of Mountain and Subpolar Glaciers: A New Global Assessment for 1961-1990

The goals of this article are (1) to combine published and unpublished mass balance measured data on more than 200 glaciers, check the quality of the data, digitize, and compile these for the period from the end of World War II (1945) to 1993 (with emphasis on the 1961-1990 period), and (2) to perform a review and analysis of this compilation. A simple global average mass balance for this period is -164 mm yr-1 (totaling -4.9 m) in water equivalent, not including iceberg calving. There are only about 40 glaciers with continuous mass balance measurements for more than 20 yr, but more than 100 with 1 to 5 yr of mass balance records. The glaciers under mass balance study differ in size from very small mountain cirque glaciers (less than 1 kin2) tO large valley glaciers (several hundred square kilometers) and subpolar ice caps with an area of several thousand square kilometers. Continuous and long-term mass balance measurements have been carried out mostly on middle-size glaciers with several exceptions. There are no longterm mass balance measurements in the following size classes: from 2-6 to 2km2; 28 to 210; and above 212 km2. The area of these unmeasured size classes of glaciers is about 200 x 103 km2, or about 29% of the global glacier area. The glacier area of mountain and subpolar glaciers (including local glaciers around Greenland and Antarctica ice sheets) is taken to be about 680 x 103 km2. The reduction in global glacier area due to retreat is calculated as 6-8 x 103 km2 from 1961-1990.

Methods of Calculation and Remote-Sensing Measurements for the Spatial Distribution of Glacier Annual Mass Balances (Abstract)

The areal distribution of glacier annual mass balance b(z) is an important characteristic of the existence of glacierization and its evolution. At present the measured value of annual mass balance at different elevations is only available for a limited number of mountain glaciers of the globe, because of the great amount of labour required for such measurements. The analysis of long-term mass-balance measurements made at Abramova Glacier, Limmerngletscher, White Glacier, Hintereisferner, and Peyto Glacier has revealed that for each year the spatial distribution of annual mass balance is well described by quadratic equations. The main variable in these equations is altitude (z). The various parameters of these formulae are estimated by the author for mean weighted height of the ablation and accumulation areas, and for the glaciers as a whole. It is found that the parameters of annual mass balance for each glacier can be calculated from formulae which include combinations of the following variables: annual balance at one of the three weighted altitudes, maximum annual snow-line elevation, annual and seasonal amounts of precipitation, and air temperatures at nearby meteorological stations. Therefore, in order to calculate the distribution of annual mass balance as a function of absolute altitude, it is sufficient to obtain a value for mass balance measured only at a single point on a glacier, and common meteorological observational data. A comparison of actual and calculated values of mass balance has shown good agreement between them. Considering the successful use of aerial remote-sensing for the measurement of snow depth in mountains by means of special stakes, it is satisfactory to accept this method for the assessment of annual mass balance at the mean weighted altitude of the ablation zone. It is possible to use aerial photo-surveys or stereophotogrammetry to resolve this problem. Then annual mass balance for the whole area of a glacier is calculated by using data from one point together with data from a nearby meteorological station.

Methods of Calculation and Remote-Sensing Measurements for the Spatial Distribution of Glacier Annual Mass Balances (Abstract)

The areal distribution of glacier annual mass balance b(z) is an important characteristic of the existence of glacierization and its evolution. At present the measured value of annual mass balance at different elevations is only available for a limited number of mountain glaciers of the globe, because of the great amount of labour required for such measurements.The analysis of long-term mass-balance measurements made at Abramova Glacier, Limmerngletscher, White Glacier, Hintereisferner, and Peyto Glacier has revealed that for each year the spatial distribution of annual mass balance is well described by quadratic equations. The main variable in these equations is altitude (z). The various parameters of these formulae are estimated by the author for mean weighted height of the ablation and accumulation areas, and for the glaciers as a whole. It is found that the parameters of annual mass balance for each glacier can be calculated from formulae which include combinations of the following variables: annual balance at one of the three weighted altitudes, maximum annual snow-line elevation, annual and seasonal amounts of precipitation, and air temperatures at nearby meteorological stations.Therefore, in order to calculate the distribution of annual mass balance as a function of absolute altitude, it is sufficient to obtain a value for mass balance measured only at a single point on a glacier, and common meteorological observational data. A comparison of actual and calculated values of mass balance has shown good agreement between them.Considering the successful use of aerial remote-sensing for the measurement of snow depth in mountains by means of special stakes, it is satisfactory to accept this method for the assessment of annual mass balance at the mean weighted altitude of the ablation zone. It is possible to use aerial photo-surveys or stereophotogrammetry to resolve this problem. Then annual mass balance for the whole area of a glacier is calculated by using data from one point together with data from a nearby meteorological station.

Methods of Calculation and Remote-Sensing Measurements for the Spatial Distribution of Glacier Annual Mass Balances

AbstractThe areal distribution of glacier annual mass balance b(z) is an important characteristic of the existence of glacierization and its evolution. At present the measured value of annual mass balance at different elevations is only available for a limited number of mountain glaciers of the globe, because of the great amount of labour required for such measurements.The analysis of long-term mass-balance measurements made at Abramova glacier, Limmerngletscher, White Glacier, Hintereisferner, and Peyto Glacier has revealed that for each year the spatial distribution of annual mass balance is well described by quadratic equations. The main variable in these equations is altitude (z). The various parameters of these formulae are estimated by the author for mean weighted height of the ablation and accumulation areas, and for the glaciers as a whole. It is found that the parameters of annual mass balance for each glacier can be calculated from formulae which include combinations of the following variables: annual balance at one of the three weighted altitudes, maximum annual snow-line elevation, annual and seasonal amounts of precipitation, and air temperatures at nearby meteorological stations.Therefore, in order to calculate the distribution of annual mass balance as a function of absolute altitude, it is sufficient to obtain a value for mass balance measured only at a single point on a glacier, and common meteorological observational data. A comparison of actual and calculated values of mass balance has shown good agreement between them.Considering the successful use of aerial remote-sensing for the measurement of snow depth in mountains by means of special stakes, it is satisfactory to accept this method for the assessment of annual mass balance at the mean weighted altitude of the ablation zone. It is possible to use aerial photo-surveys or stereophotogrammetry to resolve this problem. Then annual mass balance for the whole area of a glacier is calculated by using data from one point together with data from a nearby meteorological station.

Methods of Calculation and Remote-Sensing Measurements for the Spatial Distribution of Glacier Annual Mass Balances

Abstract The areal distribution of glacier annual mass balance b(z) is an important characteristic of the existence of glacierization and its evolution. At present the measured value of annual mass balance at different elevations is only available for a limited number of mountain glaciers of the globe, because of the great amount of labour required for such measurements. The analysis of long-term mass-balance measurements made at Abramova glacier, Limmerngletscher, White Glacier, Hintereisferner, and Peyto Glacier has revealed that for each year the spatial distribution of annual mass balance is well described by quadratic equations. The main variable in these equations is altitude (z). The various parameters of these formulae are estimated by the author for mean weighted height of the ablation and accumulation areas, and for the glaciers as a whole. It is found that the parameters of annual mass balance for each glacier can be calculated from formulae which include combinations of the following variables: annual balance at one of the three weighted altitudes, maximum annual snow-line elevation, annual and seasonal amounts of precipitation, and air temperatures at nearby meteorological stations. Therefore, in order to calculate the distribution of annual mass balance as a function of absolute altitude, it is sufficient to obtain a value for mass balance measured only at a single point on a glacier, and common meteorological observational data. A comparison of actual and calculated values of mass balance has shown good agreement between them. Considering the successful use of aerial remote-sensing for the measurement of snow depth in mountains by means of special stakes, it is satisfactory to accept this method for the assessment of annual mass balance at the mean weighted altitude of the ablation zone. It is possible to use aerial photo-surveys or stereophotogrammetry to resolve this problem. Then annual mass balance for the whole area of a glacier is calculated by using data from one point together with data from a nearby meteorological station.