Un indice circumpolaire

• Published in: Annales de Géographie
• Format: Article in Journal/Newspaper
• Language: French
• Published: PERSEE 1968
• Subjects: Arctic; Arctic Ocean; Canada; Greenland; Alaska
• Online Access: http://www.persee.fr/doc/geo_0003-4010_1968_num_77_422_15690; https://doi.org/10.3406/geo.1968.15690

Un indice circumpolaire. - Résumé. - Le faciès des régions froides de latitude élevée est défini habituellement par différents thèmes classiques qui ne peuvent, pris isolément, exprimer la notion complexe de ces milieux. Profitant des recherches des vingt dernières années, nous proposons un nouvel indice polaire, quantitatif et global, fondé sur dix critères: latitude, nombre de jours au-dessus de 42 ° F, indice thermique négatif, types de glace, précipitations, couvert végétal, accessibilité autre que par air, services aériens, population, degré de l'activité économique. Chaque thème vaut un maximum de 100 «valeurs polaires» ou VAPO; la somme des dix pointages donne la polaricité totale du poste étudié, le maximum de 1 000 unités étant théoriquement atteint au Pôle. Dans l'hémisphère Nord, nous utilisons l'isoligne de 200 VAPO comme limite sud du monde nordique, frontière qui constitue une frange environ 50 km de largeur. Les seuils de 500 et 800 VAPO permettent en outre d'établir une régionalisation latitudinale de la partie froide de l'hémisphère boréal. Du sud au nord, s'étagent Pré-Nord, Moyen-Nord, Grand-Nord et Extrême-Nord. A circum-polar index - Abstract. - Usually the characteristics of cold regions are defined by various classic criteria; taken separately, they cannot express the complex notion of cold environments. Taking advantage of the research work done over the past twenty years, we can propose new polar index, quantitative and comprehensive. Based on ten criteria : latitude, the number of days with temperature of above 42 ° F, the negative thermal index, types of ice, precipitations vegetation cover, accessibility other than by air, air services, population and the extent of economic activity. Each criterion is given the value of 100 «Polar Values» or VAPO. The total number of units of the ten critera gives the total polaricity of the station under question. A maximum of 1 000 units would, in theory, represent the Pole itself. In the Northern Hemisphere, we have taken the line representing 200 VAPO as the southern limit of the northern region, a frontier about 50 kilometers wide. The graduations marked by 500 and 800 VAPO enable us to establish a latitudinal regional pattern for the cold regions of the Northern Hemisphere. From south to north these regions read Pre-North, Middle North, Far North and Extreme North. It becomes possible to make local or regional comparisons of various parts of the northern region. The major part of the Arctic Ocean and Greenland are in the Extreme North whereas 2/3 of Alaska and the U.K S.S., the whole of the non-temperate zone of Scandinavia can be classified as Middle North. Compared to its neighbours Canada is subjected to a higher degree of polaricity. In spite of local variations the data of the polar index are presented as being the inverse value of ecoumenicity.