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| Titel |
Atmospheric transport of water to the European Arctic simulated with a mesoscale model with water vapour tracers: sources, structure, and energy considerations |
| VerfasserIn |
H. Sodemann, A. Stohl |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250023383
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| Zusammenfassung |
| Coastal areas at the end of the storm track, such as the Norwegian west coast, are prone to
heavy precipitation associated with moisture conveyor belts or atmospheric rivers. Previous
studies have shown that both, remote and local moisture transport contribute to such heavy
precipitation events. During winter 2006/2007, a series of mid-latitude cyclones brought
above-average precipitation to southern Norway. We present an analysis of the transport
processes for water vapour and latent heat from the evaporation sources in the North Atlantic
for this period, using a mesoscale model with water vapour tracers. Water vapour tracers
allow to tag water vapour by source region, and to follow its movement throughout the
model’s hydrological cycle, including parameterized diabatic processes. Several cases of
cyclonic transport are analysed from a model simulation covering December 2006,
using ECMWF’s high-resolution operational data as initialisation and boundary
conditions.
We use a new composite visualisation to reveal the horizontal and vertical structure of the
moisture transport associated with several mid-latitude cyclones. Our results confirm
that the tropospheric water transport is strongly inter-related with the upper-level
circulation, in particular with respect to the formation of filaments of large values of
vertically integrated water vapour. For the cases analysed here, it is shown that water
vapour can be transported over longer distances within such filaments, and that
different sources contribute to the total water vapour at different altitudes. It is shown
that heavy precipitation events in southern Norway contain more moisture from
long-range transport than average. In addition, we quantify the contribution of different
areas of the North Atlantic to the meridional transport of water vapour and latent
heat into the European Arctic, providing detailed insight into the mechanisms of
moisture transport within and precipitation from mid-latitude cyclones. Water tracers in
mesoscale model simulations offer new possibilities for the quantification of mass and
energy transport, for understanding the processes leading to heavy precipitation
events, and for the validation of a model’s hydrological cycle with observations. |
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