Changing summer precipitation variability in the Alpine region: on the role of scale dependent atmospheric drivers

• Published in: Climate Dynamics
• Main Authors: Haslinger, Klaus, Hofstätter, Michael, Schöner, Wolfgang, Blöschl, Günter
• Other Authors: Austrian Science Fund, Bundesministerium für Bildung, Wissenschaft und Kultur
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science and Business Media LLC 2021
• Subjects: Atmospheric Science; North Atlantic
• Online Access: http://dx.doi.org/10.1007/s00382-021-05753-5; https://link.springer.com/content/pdf/10.1007/s00382-021-05753-5.pdf; https://link.springer.com/article/10.1007/s00382-021-05753-5/fulltext.html

Abstract Summer precipitation totals in the Alpine Region do not exhibit a systematic trend over the last 120 years. However, we find significant low frequency periodicity of interannual variability which occurs in synchronization with a dominant two-phase state of the atmospheric circulation over the Alps. Enhanced meridional flow increases precipitation variability through positive soil moisture precipitation feedbacks on the regional scale, whereas enhanced zonal flow results in less variability through constant moisture flow from the Atlantic and suppressed feedbacks with the land surface. The dominant state of the atmospheric circulation over the Alps in these periods appears to be steered by zonal sea surface temperature gradients in the mid-latitude North Atlantic. The strength and the location of the westerlies in the mid-latitude Atlantic play an important role in the physical mechanisms linking atmosphere and oceanic temperature gradients and the meridional/zonal circulation characteristics.