Thermal effects of the North Atlantic Oscillation on the cold period of the year in Lithuania

Climate Research

Arunas Bukantis¹  Galina Bartkeviciene¹ 

关键词: NAO;    Indices;    temperature anomaly;    Lithuania;    synoptic climatology;   

DOI  :  10.3354/cr028221

来源: Inter-Research Science Publishing

【 摘 要 】

ABSTRACT: The impact of the North Atlantic Oscillation (NAO) on long-term air temperature fluctuations in Lithuania was studied for the period 1865 to 2000. Mean monthly values of 2 NAO indices (NAO-1, NAO-2) and air temperatures at 9 Lithuanianmeteorological stations were used as references. Synoptic situations, as well as the mean sea level pressure (SLP) and 500 hPa geopotential height field of a total of 265 months, were analysed. NAO conditions were classified as positive, negative orneutral. air temperature fluctuations in Lithuania during the cold period of the year (November to March) are positively correlated with fluctuations of the NAO indices. During periods of extreme NAO indices (| I | > ±1.5σ),a negative NAO phase is usually correlated (75 to 88% of the cases) to negative temperature anomalies, whereas a positive NAO phase is correlated to positive temperature anomalies. In the other cases, reserve impact of positive and negative NAO patterns,the relation between NAO phases and regional temerature anomalies is opposite or not detectable . Also, this study includes the analysis of atypical periods of NAO like circulation: when positive NAO phase was related to negative temperature anomalies andnegative NAO phaase to positive temperature anomalies in Lithuania.

【 授权许可】

Unknown