Ambiances climatiques instantanées

• Published in: Norois
• Main Author: Joly, Daniel
• Format: Article in Journal/Newspaper
• Language: French
• Published: Presses universitaires de Rennes 2004
• Subjects: ambiance climatique instantanée; microclimatologie; climatological instantaneous ambiance; microclimatology; geo; envir; Arctic; Isfjord; Arctique*; Spitsberg
• Online Access: https://doi.org/10.4000/norois.1016; http://journals.openedition.org/norois/1016

This paper presents a method of climate analysis applied to the Arctic area. The data taken into account were recorded at Isfjord Radio (Spitsberg) and concerned the weather, which is regularly described (6 h, 12 h, 18 h and 24 h). Data are classified by a deductive model using four parameters (cloudiness, wind speed, yes/no precipitation when the weather is observed and before the observation time). Each resulting class is called “climatological instantaneous ambiance” (ACI) and could be interpreted as an elementary unit of weather. The method allows statistics on the climatic components (temperature, relative humidity, wind section, …) and on the temporal characteristics (duration, links between the different ACI, daily associations of ACI,…) of each ACI. This method was applied to explain the spatial temperature variation. Spatial models at two main scales (local and micro-local) were established for different ACI. Three main parameters, which explain the spatial temperature variation, are logically included into the ACI definition:– Cloudiness, which controls the energy exchanges,– Wind speed, which controls the turbulence and reduces the temperature differences between the stations,– Precipitation.Therefore the ACI is helpful for microclimatological purpose La méthode fondée sur le recours aux ambiances climatiques instantanées (ACI) a été mise au point pour analyser le climat d’un site tant d’un point de vue temporel que spatial. A Isfjord Radio, station norvégienne du haut Arctique (Spitsberg) où la méthode a été testée, le temps est observé à intervalle régulier de 6 h. Une classification de ce corpus sur la base de quatre descripteurs structurants (nébulosité, force du vent, présence de précipitations au moment et au cours du laps de 6 h précédent le moment où l’observation du temps) est effectuée : les classes obtenues sont les ACI. Ces dernières correspondent donc aux unités élémentaires du « temps qu’il fait à un moment précis et en un lieu donné ». Ce corpus de données autorise de nombreuses ...