IMPACT OF THE MACRO-SCALE ATMOSPHERIC CIRCULATION ON SNOW COVER DURATION IN ROMANIA
Abstract. The main purpose of this paper is to analyze the influence of atmospheric circulation, expressed by the North Atlantic Oscillation (NAO) index on snow cover duration in Romania. The correlation coefficients between the NAO index values and the monthly number of days with snow cover at 99 s...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.546.4200 http://www.map.meteoswiss.ch/map-doc/icam2005/pdf/poster-sesion-d/D23.pdf |
| Summary: | Abstract. The main purpose of this paper is to analyze the influence of atmospheric circulation, expressed by the North Atlantic Oscillation (NAO) index on snow cover duration in Romania. The correlation coefficients between the NAO index values and the monthly number of days with snow cover at 99 stations from December to March 1961-1990 are mostly negative. The strongest correlation was obtained in southwestern Romania in January. The monthly mean number of days with snow cover decreases from the northwestern to the southeastern Romania, reaching the greatest values in the mountainous area. The snow cover is more persistent in January and March during the NAO positive phase and in December during the negative one. The dependency of snow cover duration on altitude appeared both for the positive and negative NAO phase. There was also examined the connection between Hess-Brezowsky circulation types frequency and NAO index. A strong positive correlation was obtained for the westerly airflows and a strong negative correlation for the northeasterly airflows. It was pointed out that the NAO positive phase leads to less snowy winter months in Romania, whereas the NAO negative phase increases the probability of snowy winters. |
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