EMS Annual Meeting Abstracts
Vol. 18, EMS2021-472, 2021, updated on 17 Apr 2023
EMS Annual Meeting 2021
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Investigating changes in atmospheric circulation patterns connected to extreme precipitation in Norway

Karianne Ødemark1,2, Malte Müller1,2, Ole Einar Tveito1, and Cyril Palerme1
Karianne Ødemark et al.
  • 1The Norwegian Meteorological Institute, OSLO, Norway
  • 2Department of Geosciences, University of Oslo, Norway

Extreme precipitation events that lead to excess surface water and flood are becoming an amplifying societal cost as a result of both the increasing precipitation amounts in recent years and urbanization. Knowledge about extreme precipitation events is important for the ability to predict them, but also to know how often they occur with various intensities in order to estimate design values for constructions and critical infrastructure. A good description of extreme precipitaton is a challenge since observation networks are often too sparse to describe the spatial structure of precipitation, and the highest amounts are most likely not captured by a precipitation gauge. For the study of extreme precipitation events by means of statistical analysis, long timesteries are required, which is a major challenge when using conventional or new observational data records.  Here, a data set constructed from the numerical seasonal prediction system at ECMWF, SEAS5, has been applied to evaluate mechanisms controlling extreme precipitation events. The construction technique gives the ability to increase the event sample size compared to conventional data sets. We analyze 3-day  maximum precipitation events in the September-October-November season for an area on the west coast of Norway, an area subject to the largest precipitation amounts in Europe. A principal component analysis of the 500 hPa geopotential anomaly has been performed to identify atmospheric circulation patterns related to the extreme precipitation events. We find that two of the EOFs are related to precipitation with high return values for the selected area. These two EOFs have a significant trend over the data period, but with opposing signs. We also investigate the connection between both sea surface temperature (SST) and sea-ice concentration in the Barents-Kara sea and the occurrence of extreme precipitation.

How to cite: Ødemark, K., Müller, M., Tveito, O. E., and Palerme, C.: Investigating changes in atmospheric circulation patterns connected to extreme precipitation in Norway, EMS Annual Meeting 2021, online, 6–10 Sep 2021, EMS2021-472, https://doi.org/10.5194/ems2021-472, 2021.

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