Atmospheric rivers moisture sources from a Lagrangian perspective
An automated atmospheric river (AR) detection algorithm is used for the North Atlantic Ocean basin, allowing the identification of the major ARs affecting western European coasts between 1979 and 2012 over the winter half-year (October to March). The entire western coast of Europe was divided into f...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-04-01
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| Series: | Earth System Dynamics |
| Online Access: | http://www.earth-syst-dynam.net/7/371/2016/esd-7-371-2016.pdf |
| Summary: | An automated atmospheric river (AR) detection algorithm is used for the
North Atlantic Ocean basin, allowing the identification of the major ARs
affecting western European coasts between 1979 and 2012 over the winter
half-year (October to March). The entire western coast of Europe was divided
into five domains, namely the Iberian Peninsula (9.75° W,
36–43.75° N), France (4.5° W, 43.75–50° N),
UK (4.5° W, 50–59° N), southern Scandinavia and the Netherlands
(5.25° E, 50–59° N), and northern Scandinavia (5.25° E, 59–70° N).
Following the identification of the main ARs that made landfall in western
Europe, a Lagrangian analysis was then applied in order to identify the main
areas where the moisture uptake was anomalous and contributed to the ARs
reaching each domain. The Lagrangian data set used was obtained from the
FLEXPART (FLEXible PARTicle dispersion) model global simulation from 1979 to 2012 and was forced by
ERA-Interim reanalysis on a 1° latitude–longitude grid.
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The results show that, in general, for all regions considered, the major
climatological areas for the anomalous moisture uptake extend along the
subtropical North Atlantic, from the Florida Peninsula (northward of
20° N) to each sink region, with the nearest coast to each
sink region always appearing as a local maximum. In addition, during AR
events the Atlantic subtropical source is reinforced and displaced, with a
slight northward movement of the sources found when the sink region is
positioned at higher latitudes. In conclusion, the results confirm not only the
anomalous advection of moisture linked to ARs from subtropical ocean areas
but also the existence of a tropical source, together with midlatitude
anomaly sources at some locations closer to AR landfalls. |
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| ISSN: | 2190-4979 2190-4987 |