ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880106

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

ABSTRACTThis is a review paper describing the history of glacier mass balance and runoff studies in Canada, evaluating the accomplishments and recommending some areas for future research and development.The diversity of the projects and the fact that many of them have evolved in purpose during their history is emphasized. Most projects have had a short duration and the International Hydro- logical Decade activities have had a profound influence on glacier studies in general.There have been considerable achievements in the collection and anlysis of data both in mass balance and in glacier runoff. Developments in technology (in computing, surveying and satellite techniques) have had a great impact on both the types of data collection and analysis.Recommendations for future research and development focus on the need for better runoff models for large, integrated mountain basins.

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880107

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

ABSTRACTBoth for local glaciers and for sectors of the Inland Ice, evidence on glacier behaviour is scattered, but work on a glacier inventory of the south-western third of Greenland has furnished a base for future studies on selected glaciers. Nearly all glacier types have been identified among the thousands of local glaciers, including surging and pulsing glaciers which have earlier been identified only in East Greenland.A basic requirement for understanding glacier behaviour is information on the mass balance. For local glaciers, most early investigations of this kind took place in East and North Greenland. However, in connection with the possible development of hydro-electric power such investigations have also been made in West Greenland in recent years on eight glaciers. Although of different types and geographical situations, their mass balance results all indicate low activity indices.Conventional techniques can be used för determining and interpreting mass balances. For the Inland Ice, mass balance studies have been made in three sectors of West Greenland; the longest series covers 5 years. However, lack of exact knowledge of the sub-glacial and surface topography, differing responses in neighbouring sectors, and the small slope of the ice sheet surface impose severe constraints on direct use and interpretation of conventional mass balance measurements.

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880108

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

ABSTRACTBoth the aims of investigations, and the characteristics of the results obtained, of changes in mass balance of whole glaciers, occupying clearly-defined drainage basins, are assessed in the context of questions concerning the role of glaciers in the basin hydrological cycle.The range of detailed mass balance data collected since 1945 is considered in terms of length and continuity of record of changes in ice storage, geographical distribution of basins with respect to the various mountain ranges and climatic regions of the world, and whether the glacierised basins are also subject to measurements of meltwater runoff and water balance.Results of ice balance determinations are available for 95 glaciers, from all major ranges with the exception of the Andes. Of these glaciers, 80 per cent are smaller in area than 10 km2. Eleven records are for periods of twenty or more years, but the glaciers with the longest records are spatially clustered particularly in Scandinavia, the European Alps, and north-western North America. In 25 of these glacierised basins, measurements of discharge have accompanied those of mass balance, but full water balance determinations with continuous monitoring of precipitation and discharge are limited to 11 basins. Records of water balance generally refer to shorter periods than those of ice balance. Although the hydrological method of determining mass balance produces results which differ from those derived from the more commonly-used glaciological method, it provides information more useful for hydrological and water resources purposes. Continuous hydrometric data also give an indication of the influence of hydrometeorological conditions on sequential changes in the mass of stored water and on temporal variation of runoff.Long term acquisition of simultaneous mass and water balance data for individual basins remains necessary in order to allow assessment of the impact of climatic shifting on both glacier mass balance and montane runoff.

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880109

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

ABSTRACTResearch on glacier mass balance began in the U.S.A. about 50 years ago. More complete studies of climate, snow and ice balance, and the hydrology of glaciers were initiated for the IGY in 1957 and the IHD in 1966. Investigations included the magnitude and geographic distribution of normal mass balance processes and unusual phenomena such as out-bursting, accumulation of ice by freezing of water in firn, and ablation of glacier ice by volcanic activity and by calving. Glacier size has been found not to be a simple function of climate as is widely imagined. Glaciers can increase with a warming of climate and can shrink due to calving instability mechanisms. Numerical modeling of glacier balance and runoff have appeared in the past decade only. Glacier research has also produced a new understanding of the nation's climate, water resources, and flood hazards because glaciers exist in very moist rather than very cold climates and produce very high runoff rates.

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880110

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

ABSTRACTThe change of mass balance/altitude profiles from years with positive to those with negative mean balance has been investigated for seven glaciers representing various climatic regions. It appears that for alpine glaciers the imbalance is nearly independent of altitude, in dry, continental regions the imbalance is largest near the equilibrium line, where albedo changes are most pronounced. Maritime glaciers owe their mass balance variations mainly to changes in the accumulation area and polar glaciers to the varying duration of ablation in their lowest parts.

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880111

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

ABSTRACTIn order to find some regional climatic significance of glaciers mass balanse a statistical examination is made of the four longest published data series in the Alps: one located in France, two in Switzerland, and one in Austria. It is clear that much of the balance fluctuations for the different glaciers along the 500 km alpine chain can be explained by temporal correlation, to about 80% of the variance, while only 10% is explained by the geographical (spatial) distribution. This homogeneity in the mass balance fluctuations facilitates an analysis of glacier variations from the same climatic signal. The available data for Norway and Sweden indicate a regional variation similar to the alpine mechanism but with a more marked spatial dependence due clearly to the different distances inland from the coast. An other data set, 9 Russian glaciers for 16 years, gives us a very good test of the spatio temporal balance distribution. Finally two balance reconstructions are examined in order to find similarities between the Alps and Scandinavia on a century.

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880112

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

ABSTRACTPatterns of annual variation of air temperature in the world provide two types of the patterns of ablation rate of the glacier, namely the“summer-maximum”and the“non-maximum”through a year, while those of precipitation and air temperature provide three types of accumulation rate, namely, the above two and the“winter-maximum”. In six combinations of these types, annual variation of balance rate can be classified into the types of the winter-maximum, the non-maximum and the summer-maximum. The“summer-accumulation type glaciers”in the Nepal Himalaya, which have more accumulation in summer than winter in the whole area of a glacier, belong to the non-maximum type of balance rate.In the case of this type glacier, direct observations of accumulation and ablation are quite difficult, since accumulation and ablation mainly occur simultaneously in summer. Therefore, the methods of estimation of accumulation and ablation are discussed. Accumulation can be estimated on the basis of the linear relation between surface air temperature and the probability of occurrence of solid precipitation in all cases of precipitation. Local characteristics of melting process of precipitation elements which control such relation are described. For the estimation of ablation, the effect of high albedo of new snow is important for the summer-accumulation type. The variation of mass balance through the balance year in the case of the summer-accumulation type is compared with that of the winter-accumulation type.

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880113

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

ABSTRACTGlaciers affect hydroelectric development by storing and rapidly releasing liquid water, by increasing the sediment load of a stream, by providing a constant source of stream-flow and by acting as naturally regulated storage reservoirs. A study was conducted in northern British Columbia to predict the probable maximum flood from a glacierized watershed in which three hydroelectric dams are planned. A streamflow model was developed to predict runoff based on weather data recorded at two stations that have been in operation since 1918. The model calculates daily glacier accumulation, ablation and the resulting annual net balance. An englacial storage and release of liquid water mechanism is proposed that is controlled primarily by season. Inflow to englacial storage is assumed to occur from late fall to mid-July, and release from storage for the remainder of the year. Implementation of this algorithm significantly reduced overall simulation error, particularly during the inflow period. The effect of the annual mass balance of these glaciers on watershed runoff was calculated for the 65 year period that these data were synthesized. It was found that increases or decreases in annual runoff of up to 40% occur in the sub-basin that is 67% glacierized.

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880114

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor