摘要:

The article examines the northern boundaries of grain production, making a distinction between “agronomic”; and “economic”; boundaries. An analysis of the available statistics reveals that between 1970 and 1975 the leading country in terms of grain production was Finland with a mean annual production of 3 million metric tons, next came Sweden, then Norway and finally the USSR, with barely 240,000 tons. North America produces no appreciable amount of grain north of 60°. The most recent trend has been a southward retreat of the “economic”; boundary of grain production, particularly marked in Finland, as a result of rising costs of production.

ISSN:0273-8457    

DOI:10.1080/10889378109388680

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Prior to his escape from Russia in 1876, P. A. Kropotkin, the geographer and anarchist, formulated an impressive plan for exploration and scientific research in the Russian Arctic, many facets of which have since been implemented. During his 40 years of exile he corresponded with such eminent Arctic explorers as Nordenskiöld, wrote articles on polar exploration and generally promoted the importance of polar research.

ISSN:0273-8457    

DOI:10.1080/10889378109388681

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Limbert's long‐term series of temperature variations for the South Orkney Islands is compared with variations in solar activity, and a direct solar‐terrestrial relationship is demonstrated. The rates of recession of glaciers and of sea level on open ocean coasts are also found to depend directly on solar activity.

ISSN:0273-8457    

DOI:10.1080/10889378109388682

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

A radar sounding technique for measuring ice velocity was developed in 1976 during a tractor‐sled traverse by the 21st Soviet Antarctic Expedition in the Molodezhnaya area, and was found to compare well with previous velocity data obtained by East German scientists in 1972 by geodetic measurements. Ice thickness measurements and barometric leveling during the 1976 traverse were also used to construct an ice profile.

ISSN:0273-8457    

DOI:10.1080/10889378109388683

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

An isopicnic model is used to compute the vertical velocity component of thermohaline water circulation in the Southern Ocean to determine zones of sinking and upwelling. The zero isotach in the upper water layer is found to move southward with depth. This resembles the meridional circulation obtained in a model by Gill and Bryan. The zonal symmetry of sinking and upwelling zones is also found to be disturbed with depth, and sinking zones become more localized in accordance with the distribution of subtropical gyres and with their displacement toward Antarctica.

ISSN:0273-8457    

DOI:10.1080/10889378109388684

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Observational data of American, Japanese and New Zealand scientists are used to analyze the heat budget of Lake Vanda, a 4‐mile‐long lake in Wright Valley, Victoria Land, whose temperature increases with depth. The analysis confirms that the deep water is being heated from the bottom up, and it is suggested that thermal waters may be the heat source.

ISSN:0273-8457    

DOI:10.1080/10889378109388685

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Direct measurements of fast‐ice temperatures in Alasheyev Bight demonstrate the strong effect of snow cover on temperature amplitude. A change from cyclonic weather to drainage wind with low air temperature is accompanied by removal of part of the snow cover that acts as a thermal insulator, reducing the amplitude of the fast‐ice temperatures. The opposite occurs with a change from drainage wind to cyclonic weather, associated with warming and snow deposition.

ISSN:0273-8457    

DOI:10.1080/10889378109388686

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Snow stakes have generally been the common technique for direct measurements of snow depths. However, on Antarctic fast ice such observations, especially for budget computations, must be adjusted for the presence of snow‐water infiltration‐congelation ice that is formed through the upward infiltration of seawater through cracks in the fast ice. Investigations in 1970 and 1971 showed that actual snow accumulation on fast ice is two to three times the snow depth that can be directly measured with a stake.

ISSN:0273-8457    

DOI:10.1080/10889378109388687

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

ISSN:0273-8457    

DOI:10.1080/10889378109388688

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor