LE SAVIEZ-VOUS ?

                                                                                                                                                                                                                                                              VORTEX POLAIRE -Tandis que plusieurs régions des États-Unis souffrent d'une vague de froid jamais vue depuis 20 ans du fait du fameux «vortex polaire», c'est le bon moment pour rappeler qu'il y a des lieux bien plus froids que cela si cela peut les rassurer  ...

                                                                                                                                                                                                       Dome Fuji, Antarctique  : - 93.2° C                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      

                                                                                                                                                                                                                              Au Au centre de l'Antarctique, entre les monts Fuji et Argus, les satellites ont affiché en août 2010 rien moins que 93,2 degrés Celsius sous la barre du zéro.

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  Selon une étude publiée en décembre dernier, cette température a été vérifiée grâce à différentes méthodes.

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               Le froid quasi constant dans cette zone, située le long d'une crête montagneuse, pourrait congeler les yeux, le nez et les poumons d'un être humain en quelques minutes. Sa température est presque de 13 degrés sous la limite (-78.5° C à laquelle le dioxyde de carbone (CO2) passe de l'état de gaz à celui de glace sèche.

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       «Cette nouvelle minimale est de 50 degrés plus froide que les températures en Alaska ou en Sibérie, et environ 30 degrés plus froide que les températures les plus froides du Groenland», a déclaré à la BBC Ted Scambos, du Centre américain d'informations sur la neige et la glace, à Boulder (Colorado).

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     Des températures aussi basses ne se calculent pas avec un thermomètre dans cette zone, totalement inhabitable, mais au moyen d'instruments scientifiques de précision à bord des satellites qui tournent autour de la Terre, parmi lesquels le Landsat 8, satellite météorologique appartenant conjointement à la NASA et au Service Géologique des États-Unis (USGS), deux agences fédérales.

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           Pour analyser les chiffres avec sûreté, les scientifiques ont analysé 32 ans de chiffres et données issus d'instruments satellitaires.

                                                                                                                                                                                                                                                                                                                                                                          Base russe Vostok, Antarctique  : - 89.2° C                                                                                                                                                                                                                                                                                                                                                                                           

                                                                                                                                                                                                                                                                           La deuxième température la plus froide de l'histoire a été enregistrée dans la même zone géographique que la première, dans la base russe de Vostok.

                                                                                                                                                                                                                                                                                                                                                                                                                      Ce fut en 1983, année où les calculs concluaient à une température de - 89.2° C. On peut voir ici la base sur une carte ... Un vaste territoire, plus grand que bon nombre de pays, avec une seule et unique population : Vostok.

                                                                                                                                                                                                                                                                                                                                                                                  Cette station de recherche scientifique, appartenant à la Russie, se trouve au Pôle Sud magnétique, à une altitude de 3500 mètres au-dessus du niveau de la mer.

                                                                                                                                                                                                                                                                                                                                                                                                     La station est située près du lac de Vostok, l'un des plus grands du monde, etrecouvert de glaciers de 4 kilomètres de long.

                                                                                                                                                                                                                                                                                                                                                                                                                 La station a été ouverte en décembre 1957, mais comme d'autres bases situées sur les pôles, ses fondations originales sont enterrées plusieurs mètres sous la glace.

                                                                                                                                                                                                                                                                                                       Elle est située à 1410 km d'une autre station russe, Mirny, et à 1260 km de la côte. La couche de glace dans cette région a une épaisseur effective de 3700 mètres.

                                                                                                                                                                                                                                                                                                                                                                                                               Base d'Amundsen-Scott, États-Unis, Pôle Sud  : - 82° C                                                                                                                                                                                                                                                                                                                                                                                                                                                         

                                                                                                                                                                                                                                                                                                                                                                                                                                                                           La base d'Amundsen-Scott est une station américaine située au centre du Pôle Sud. Elle est habitée en permanence. La température la plus extrême enregistrée y fut de - 82,8º C et la moyenne annuelle oscille autour de - 49° C.   

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              Comme la base de Vostok, ses fondations originales mises sur pied dans les années 50 sont enterrées sous 10 mètres de neige, voire plus. De temps en temps, une nouvelle structure doit être construite par-dessus les fondations déjà ensevelies.

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  Village de Oymyakon, Russie  :  - 71,2º C                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    Le lieu habité le plus froid de la planète, avec entre 500 et 900 habitants, est le village d'Oymyakon. Celui-ci se situe en République de Saja, qui appartient à la Fédération de Russie, à 350 kilomètres au sud du cercle polaire arctique.

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    En 1926, la température la plus basse de l'hémisphère nord y a été enregistrée  : 71,2º degrés au-dessous de zéro. Une plaque commémorative de l'événement a été érigée.

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                Oymyakon se situe à l'est de Yakutia, à une altitude de 750 mètres au-dessus du niveau de la mer. Une journée y dure trois heures en décembre. Les températures en hiver oscillent entre - 50 et - 47° C.

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                A Oymyakon, l'hiver dure neuf mois. Les poissons sont congelés 30 secondes après avoir été sortis du fleuve, et les moteurs des voitures restent allumés en permanence car dans le cas contraire, l'essence se solidifierait.

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   Les téléphones portables n'existent pas car à ces températures, ils seraient endommagés.

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                Ville de Verkhoyansk, Russie  : - 69,8° C                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              Verkhoyansk se trouve à l'orée du fleuve Yana, entre les montagnes et la cordillère de Verjoiansk.

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    La ville compte actuellement 1.200 habitants. Son record de température la plus basse a eu lieu le 7 février 1892. L'hiver la température moyenne est de - 46,2 °C.

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               Station de North Ice, Groënland  : -  66,1° C                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  

                                                                                                                                                                                                                                                                                         North Ice était auparavant une station de recherche de l'expédition British North à l'intérieur du Groenland.

Autour du site se trouvent plusieurs villages dans lesquels, le 9 janvier 1954, a été enregistrée une température de - 66,1° C.

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         Snag, Yukon, Canada  : - 64º C                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      La population de Snag, au Canada, ne comprend que 10 natifs et un groupe de scientifiques et météorologues. Le village est en général considéré comme le lieu le plus froid d'Amérique du Nord.

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                Avec une température de - 64º C  à - 83º F, Snag a décroché en 1947 le record de la température la plus basse enregistrée en Amérique du Nord.