Characterization of the atmospheric environment during extreme precipitation events associated with atmospheric rivers in Norway - Seasonal and regional aspects

Autor(en)
Clio Michel, Asgeir Sorteberg, Sabine Eckhardt, Chris Weijenborg, Andreas Stohl, Massimo Cassiani
Abstrakt

Extreme precipitation events in Norway in all seasons are often linked to atmospheric rivers (AR). We show that during the period 1979–2018 78.5% of the daily extreme precipitation events in Southwestern Norway are linked to ARs, this percentage decreasing to 59% in the more northern coastal regions and ~40% in the inland regions. The association of extreme precipitation with AR occurs most often in fall for the coastal areas and in summer inland. All Norwegian regions experience stronger winds and 1–2°C increase of the temperature at 850 hPa during AR events compared to the climatology, the extreme precipitation largely contributing to the wet climatology (only considering rainy days) in Norway but also in Denmark and Sweden when the rest of Europe is dry. A cyclone is found nearby the AR landfall point in 70% of the cases. When the cyclone is located over the British Isles, as it is typically the case when ARs reach Southeastern Norway, it is associated with cyclonic Rossby wave breaking whereas when the ARs reach more northern regions, anticyclonic wave breaking occurs over Northern Europe. Cyclone-centered composites show that the mean sea level pressure is not significantly different between the eight Norwegian regions, that baroclinic interaction can still take place although the cyclone is close to its decay phase and that the maximum precipitation occurs ahead of the AR. Lagrangian air parcel tracking shows that moisture uptake mainly occurs over the North Atlantic for the coastal regions with an additional source over Europe for the more eastern and inland regions.

Organisation(en)
Institut für Meteorologie und Geophysik
Externe Organisation(en)
University of Bergen (UiB), Wageningen University and Research Centre, Norwegian Institute for Air Research
Journal
Weather and Climate Extremes
Band
34
Anzahl der Seiten
15
DOI
https://doi.org/10.1016/j.wace.2021.100370
Publikationsdatum
12-2021
Peer-reviewed
Ja
ÖFOS 2012
105206 Meteorologie
Schlagwörter
ASJC Scopus Sachgebiete
Geography, Planning and Development, Management, Monitoring, Policy and Law, Atmospheric Science
Link zum Portal
https://ucris.univie.ac.at/portal/de/publications/characterization-of-the-atmospheric-environment-during-extreme-precipitation-events-associated-with-atmospheric-rivers-in-norway--seasonal-and-regional-aspects(42f27570-f98f-4904-a0a2-ed09e50c4fc6).html