摘要:

AbstractThis work is based on a study of the relative hypsographic curves of 48 lakes. The five largest belong to the Great Lakes System, the rest of the lakes are Swedish. A method for determining a mean lake form as well as statistically defined deviations from this mean is introduced. A classification system for lakes based on the lake form is discussed. A method for determining the error in lake volume calculations is presented and formulas to correct for the volume error are derived. A first outline of a model for optimization of lake hypsographic surveys is discussed.

ISSN:0435-3676    

DOI:10.1080/04353676.1977.11879944

出版商:Taylor&Francis    

年代:1977

数据来源: Taylor

摘要:

AbstractThis paper reviews recent work (1960—present) on the geomorphic activity of snow avalanches. The spatial distribution of avalanche activity in mountain areas is strongly localised by topographic, vegetational and climatic controls. Optimal conditions for avalanche landforms occur on open, 25–50°slopes with well established avalanche tracks mantled by loose debris. Above treeline therefore, avalanches are a major process of loose debris transfer whereas below treeline their effects are mainly hydrologic or as a modifier of vegetation. Major landforms produced by snow avalanches are both erosional and depositional and may involve the modification of existing forms (e.g. gullies, talus) or the creation of new ones e.g. avalanche boulder tongues, avalanche pits.Published work in the last 15 years has corroborated Rapp's work in Scandinavia by recognising similar avalanche phenomena in other mountain areas and adding quantitative data on the amount and manner of debris movement by avalanches. The major developments have been the recognition of the importance and character of avalanche effects on alpine talus slopes and the effects of avalanches on snowmelt hydrology.

ISSN:0435-3676    

DOI:10.1080/04353676.1977.11879945

出版商:Taylor&Francis    

年代:1977

数据来源: Taylor

摘要:

AbstractRecreational pressure on land above the treeline in the Swedish mountains has increased rapidly in recent years. Increased popularity of hiking in particular has in some areas resulted in trail erosion and landscape degradation. A study of recreational impact on hiking trails near Grövelsjön has shown that where use intensity is uniform incidence of damage depends largely on soil properties and profile characteristics. Properties of particular significance arc: abundance of rocks, homogeneity of texture, iron-pan morphology, aggregate stability and organic content. Organic soils are shown to be highly vulnerable to damage, especially during the peak tourist season when moisture contents are high. Severity of trail damage is discussed in relation to land-use planning objectives and recommendations are made for abandonment of the policy of trailmarking on lands above the treeline.

ISSN:0435-3676    

DOI:10.1080/04353676.1977.11879946

出版商:Taylor&Francis    

年代:1977

数据来源: Taylor

摘要:

AbstractWith the help of the World Meteorological Organization (WMO), Afghanistan in 1955 started a programme of establishing a network of surface and upper air observing stations. Some of the data collected are used to study the behaviour of the Asian Summer Monsoon in eastern Afghanistan. A more detailed mean pressure chart of the monsoon heat lows over Pakistan and Afghanistan is presented, as well as an analysis of the monsoon rainfall distribution. The monsoon circulation over eastern Afghanistan and the movements of the Intertropical Front (ITF) are discussed, making use of additional unpublished data.

ISSN:0435-3676    

DOI:10.1080/04353676.1977.11879947

出版商:Taylor&Francis    

年代:1977

数据来源: Taylor

ISSN:0435-3676    

DOI:10.1080/04353676.1977.11879943

出版商:Taylor&Francis    

年代:1977

数据来源: Taylor