Glacier Water Research Articles

EFFECT OF SNOW AND FIRN HYDROLOGY ON THE PHYSICAL AND CHEMICAL CHARACTERISTICS OF GLACIAL RUNOFF

Near-surface processes on glaciers, including water flow over bare ice and through seasonal snow and firn, have a significant effect on the speed, volume and chemistry of water flow through the glacier. The transient nature of the seasonal snow profoundly affects the water discharge and chemistry. Water flow through snow is fairly slow compared with flow over bare ice and a thinning snowpack on a glacier decreases the delay between peak meltwater input and peak stream discharge. Furthermore, early spring melt flushes the snowpack of solutes and by mid-summer the melt water flowing into the glacier is fairly clean by comparison. The firn, a relatively constant feature of glaciers, attenuates variations in water drainage into the glacier by temporarily storing water in saturated layer. Bare ice exerts opposite influences by accentuating variations in runoff by water flowing over the ice surface. The melt of firn and ice contributes relatively clean (solute-free) water to the glacier water system.

Evolution of glaciation in the Pamiro-Alai mountains and its effect on river run-off

AbstractThe aim of the present research is to evaluate changes in the glacierized area, glacier-water resources and glacial run-off during the last 25–30 years. The prevailing process of degradation has resulted in a 16% diminution of the glacierized area in Gissaro-Alai and 11% in the Pamirs. The ratio between the advancing, stationary and retreating glaciers in the Gissaro-Alai mountains is 1:5:17, and the one in the Pamirs is 1:1:4. Moraine-covering of the glaciers has increased from 8 to 11 % in the Gissaro-Alai and from 6 to 11 % in the Pamirs. Ice-volume diminution of glaciers in the Gissaro-Alai is 17% and in the Pamirs it is 12%. The mean long-term annual volume of total glacial melting, glacial run-off and variation coefficients of these values in the river basins of the Pamirs and the Gissaro-Alai are described as functions of the altitudes of glacier termini, equilibrium lines and a new parameter, which characterizes the influence of the glacierized area distribution according to altitude on run-off. The data presented here indicate changes in mean annual volumes of glacier water yield in the river basins of the Pamirs and the Gissaro-Alai mountains, related to glaciation evolution in 1957–80.

Evolution of glaciation in the Pamiro-Alai mountains and its effect on river run-off

Abstract The aim of the present research is to evaluate changes in the glacierized area, glacier-water resources and glacial run-off during the last 25–30 years. The prevailing process of degradation has resulted in a 16% diminution of the glacierized area in Gissaro-Alai and 11% in the Pamirs. The ratio between the advancing, stationary and retreating glaciers in the Gissaro-Alai mountains is 1:5:17, and the one in the Pamirs is 1:1:4. Moraine-covering of the glaciers has increased from 8 to 11 % in the Gissaro-Alai and from 6 to 11 % in the Pamirs. Ice-volume diminution of glaciers in the Gissaro-Alai is 17% and in the Pamirs it is 12%. The mean long-term annual volume of total glacial melting, glacial run-off and variation coefficients of these values in the river basins of the Pamirs and the Gissaro-Alai are described as functions of the altitudes of glacier termini, equilibrium lines and a new parameter, which characterizes the influence of the glacierized area distribution according to altitude on run-off. The data presented here indicate changes in mean annual volumes of glacier water yield in the river basins of the Pamirs and the Gissaro-Alai mountains, related to glaciation evolution in 1957–80.

Study of glacier meltwater resources in China

Glacier meltwaters are an important component of surface water resources in western China. Based on glacier inventories, the total glacier area in China is 5.87 x 104km2, the second largest for an Asian country. The total storage of water in glaciers is about 5132 x 103 km3, and the mean annual amount of glacier melt runoff is about 5.64 x 1010m3, o r 2% of the total surface water resources of China. From the late 1950s to the present, measurements have been undertaken of about twenty mountain glaciers, and data on hydrology and meteorology obtained. The relationship between heat balance and glacier ablation has been investigated but for glacierized areas where there are no data, ice-melt runoff can be estimated from climatic data. Runoff of glacier meltwater decreases with increasing aridity of the climate. The impact of glacier meltwater on the regimes of mountain streams in different environments are described in this paper.

Study of glacier meltwater resources in China

Glacier meltwaters are an important component of surface water resources in western China. Based on glacier inventories, the total glacier area in China is 5.87 x 104km2, the second largest for an Asian country. The total storage of water in glaciers is about 5132 x 103 km3, and the mean annual amount of glacier melt runoff is about 5.64 x 1010m3, o r 2% of the total surface water resources of China. From the late 1950s to the present, measurements have been undertaken of about twenty mountain glaciers, and data on hydrology and meteorology obtained. The relationship between heat balance and glacier ablation has been investigated but for glacierized areas where there are no data, ice-melt runoff can be estimated from climatic data. Runoff of glacier meltwater decreases with increasing aridity of the climate. The impact of glacier meltwater on the regimes of mountain streams in different environments are described in this paper.

Himalayan glaciers as a sustainable water resource

The Himalayan glaciers, which number around 15 000, cover an area of 33 000 km2 and are nursed in the steepest and highest valleys in the world. Runoff from the seasonal melting of snow and ice contributes to the streamflows of the Indus, Ganga and Brahamputra river systems of the Indian subcontinent. The annual contribution from snowmelt and runoff from non‐glacierized areas during the early part of summer (April to June) amounts to 20%. As summer proceeds (July to September) the contributions from melting glacier ice and water stored within the glaciers reach 50%. In this paper the pattern of water release by melting and its chemical characteristics are described for a glacier in the Lahul‐Spiti valley of Himachal Pradesh, India.

Colors of glacier water

The optical characteristics of sediment suspensions in the glacierfed lake Veitastrondsvatn are examined to explain observed color variations. The color depends on the wavelength where the ratio between the backward scattering coefficient and the absorption coefficient of the suspension has its maximum, and this usually coincides with the wavelength where the absorption has its minimum. It is found that the absorption coefficient of the small particles of clay and silt size decreases with increasing wavelength, but that the absorption coefficient of the suspension obtains a minimum in the green part of the spectrum, due to the strong absorption of red light by water. The suspension of such particles in the surface layer of the lake will then appear green. The coefficients of larger particles of sand size are almost independent of wavelength, with no significant maximum or minimum, and river waters close to the glacier fronts, which are dominated by these particles, will appear milky.

Recrystallisation and electrical behaviour of glacier ice

Electrical d.c. resistivity measurements made on the George VI Ice Shelf have established the polar nature of Antarctic ice despite saturation by melt-water from surface melt-lakes. Previously it has been suggested that different impurity concentrations are responsible for the extremes in resistivity (a factor of 1,000) between temperate ice (essentially at its pressure melting point) and polar ice (well below its pressure melting point). However, the evidence suggests that impurity levels are similar despite the leaching of contaminants by free water in temperate glaciers, a process which is absent in true polar glaciers. This implies that, although impurities can significantly alter the electrical behaviour of glacier ice, there is a more fundamental mechanism at work. We suggest that this process is one of recrystallisation.

Movement of Water in Glaciers

AbstractA network of passages situated along three-grain intersections enables water to percolate through temperate glacier ice. The deformability of the ice allows the passages to expand and contract in response to changes in pressure, and melting of the passage walls by heat generated by viscous dissipation and carried by above-freezing water causes the larger passages gradually to increase in size at the expense of the smaller ones. Thus, the behavior of the passages is primarily the result of three basic characteristics: (1) the capacity of the system continually adjusts, though not instantly, to fluctuations in the supply of melt water; (2) the direction of movement of the water is determined mainly by the ambient pressure in the ice, which in turn is governed primarily by the slope of the ice surface and secondarily by the local topography of the glacier bed; and, most important, (3) the network of passages tends in time to become arborescent, with a superglacial part much like an ordinary river system in a karst region, an englacial part comprised of tree-like systems of passages penetrating the ice from bed to surface, and a subglacial part consisting of tunnels in the ice carrying water and sediment along the glacier bed. These characteristics indicate that a sheet-like basal water layer under a glacier would normally be unstable, the stable form being tunnels; and they explain, among other things, why ice-marginal melt-water streams and lakes are so common, why eskers, which are generally considered to have formed in subglacial passages, trend in the general direction of ice flow with a tendency to follow valley floors and to cross divides at their lowest points, why they are typically discontinuous where they cross ridge crests, why they sometimes contain fragments from bedrock outcrops near the esker but not actually crossed by it, and why they seem to be formed mostly during the later stages of glaciation.

Movement of Water in Glaciers

Abstract A network of passages situated along three-grain intersections enables water to percolate through temperate glacier ice. The deformability of the ice allows the passages to expand and contract in response to changes in pressure, and melting of the passage walls by heat generated by viscous dissipation and carried by above-freezing water causes the larger passages gradually to increase in size at the expense of the smaller ones. Thus, the behavior of the passages is primarily the result of three basic characteristics: (1) the capacity of the system continually adjusts, though not instantly, to fluctuations in the supply of melt water; (2) the direction of movement of the water is determined mainly by the ambient pressure in the ice, which in turn is governed primarily by the slope of the ice surface and secondarily by the local topography of the glacier bed; and, most important, (3) the network of passages tends in time to become arborescent, with a superglacial part much like an ordinary river system in a karst region, an englacial part comprised of tree-like systems of passages penetrating the ice from bed to surface, and a subglacial part consisting of tunnels in the ice carrying water and sediment along the glacier bed. These characteristics indicate that a sheet-like basal water layer under a glacier would normally be unstable, the stable form being tunnels; and they explain, among other things, why ice-marginal melt-water streams and lakes are so common, why eskers, which are generally considered to have formed in subglacial passages, trend in the general direction of ice flow with a tendency to follow valley floors and to cross divides at their lowest points, why they are typically discontinuous where they cross ridge crests, why they sometimes contain fragments from bedrock outcrops near the esker but not actually crossed by it, and why they seem to be formed mostly during the later stages of glaciation.

Glaciers and the water supply

AN stored enormous in the reserve form of of glacier water ice is : st red in the for of lacier ic : about three-fourths of all the fresh water in the world, equivalent to precipitation over the entire globe for about 60 years. In North America, the volume of water stored as snow and ice in glaciers is many times greater than that stored in all of the lakes, ponds, rivers, and reservoirs on the continent. Most glaciers, however, are in the polar and subpolar regions, and not where most people live. People and glaciers do meet in Alaska, of course. About 3 per cent of that state (about 20,000 sqmi or 52,000 sqkm) is covered by glaciers, and this ice is concentrated in mountains not far from major population centers. Most of the major rivers originate at glaciers, and the peculiar characteristics of glacier runoff (peak flow in midsummer, diurnal fluctuations in runoff, high silt content, glacier outburst floods) do have a pronounced effect on the society and economy of Alaska. The impact of glaciers on water resource development is probably greatest in the Pacific Northwest and the middle and northern Rocky Mountain states. The glaciers there are small, almost inconsequential by Alaskan or arctic standards, but they are an important source of streamflow. The location of glaciers in the United States exclusive of Alaska is shown in Fig. 1, and the numbers and the areas of these glaciers are summarized in Table 1. These data are approximate only; many glaciers occur in relatively inaccessible and poorly mapped areas. A new inventory of glacier ice is underway as a major project of the International Hydrological Decade. The first results of this inventory in the United States indicate that about 20 per cent more glaciers exist in the highly glacerized North Cascade Range of Washington than had been counted in a previous inventory.1 It is likely that the total numbers and areas of glaciers shown in Table 1 represent minimum figures. These glaciers are small but numerous, adding up to a considerable equivalent volume of water, and they release an appreciable amount of water during the summer months. In Washington, as much water is stored as glacier ice (about 40 mil acre-ft or 49 billion cu m) as in all of the reservoirs, lakes, and rivers in the state, and as much water is released to summertime streamflow as is pumped from ground water all year. The importance of these small ice masses to water resource development stems partly from the quantity of water released, but results even more from the seasonal and long-term natural regulation of this water. This regulation makes the water a more reliable source in one respect, but it also makes forecasting its seasonal release virtually impossible by ordinary procedures.

The exchange of hydrogen isotopes between ice and water in temperature glaciers

Isotopic exchange between ice and water is found to take place in temperate glaciers. This exchange causes homogenization of deuterium in snow during summer thaws, together with a general increase in deuterium concentration. Ice in a temperate glacier is therefore more homogeneous and has a higher deuterium concentration than the precipitation on the glacier. The difference between the average deuterium concentration in ice and precipitation gives information about the runoff ratio.

Einige geoelektrische Untersuchungen auf österreichischen Gletschern

Experiments to determine the thickness of glaciers by high frequency prospecting were carried out on the Austrian glacier Hintereisferner in 1938. After the war electrohydrographical measurements on glacier rivulets were carried out in the Kaprun Valley. The resistance of the glacier water fluctuates according to the time of season. It depends on the respective composition of these waters (Fig. 2). Therefore the geologic and mineralogic properties of the glacier-water may be deducted from the electric resistance. Especially the amount of surface water may be deducted (Fig. 3). An example is shown in Fig. 4.