Impact of the North Atlantic Oscillation on winter climate of Germany

• Published in: Tellus A: Dynamic Meteorology and Oceanography
• Main Authors: Syed M. F. Riaz, M. J. Iqbal, Sultan Hameed
• Format: Article in Journal/Newspaper
• Language: English
• Published: Stockholm University Press 2017
• Subjects: Germany; winter climate; North Atlantic Oscillation; Oceanography; GC1-1581; Meteorology. Climatology; QC851-999; North Atlantic; North Atlantic oscillation
• Online Access: https://doi.org/10.1080/16000870.2017.1406263; https://doaj.org/article/a8a7681629d24b21a77c190a0db58ecd

Correlations of the North Atlantic Oscillation (NAO) with climate variables in Europe are strong in the north and the south of Europe but there is a zone of statistically not significant correlations in between. This paper presents evidence that the impact of NAO can be ascertained more clearly by decomposing it into its constituent centres of action (COA), the Azores High (AZH) and the Icelandic Low (IL), each of which varies continuously in intensity as well as position. Monthly values of intensity and latitude and longitude positions for each COA are estimated from sea level pressure data. These are used to analyse their impact on interannual variations of winter precipitation and climate of Germany. Correlation of NAO with winter precipitation is weak but statistically significant in north Germany and not significant in south Germany. By separately calculating correlations with the AZH and the IL, it is found that the primary influence on the interannual variations of winter precipitation and surface temperature over both north and south Germany is the zonal migration of the IL. When the IL is situated east of its mean location, there is above normal precipitation and warmer temperatures over Germany and in winters when the IL is situated west of its mean longitudinal position, drier and colder conditions occur over Germany. The impact of this teleconnection is greater in north Germany than in the south, presumably because of the mountainous topography in the south which hinders wind flow.