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A climatology of strong large-scale ocean evaporation events. Part I : Identification, global distribution, and associated climate conditions

Aemisegger, Franziska LU and Papritz, Lukas (2018) In Journal of Climate 31(18). p.7287-7312
Abstract

This paper presents an object-based, global climatology (1979-2014) of strong large-scale ocean evaporation (SLOE) and its associated climatic properties. SLOE is diagnosed using an ''atmospheric moisture uptake efficiency'' criterion related to the ratio of surface evaporation and integrated water vapor content in the near-surface atmosphere. The chosen Eulerian identification procedure focuses on events that strongly contribute to the available near-surface atmospheric humidity. SLOE is particularly frequent along the warm ocean western boundary currents, downstream of large continental areas, and at the sea ice edge in polar regions with frequent cold-air outbreaks. Furthermore, wind-driven SLOE occurs in regions with topographically... (More)

This paper presents an object-based, global climatology (1979-2014) of strong large-scale ocean evaporation (SLOE) and its associated climatic properties. SLOE is diagnosed using an ''atmospheric moisture uptake efficiency'' criterion related to the ratio of surface evaporation and integrated water vapor content in the near-surface atmosphere. The chosen Eulerian identification procedure focuses on events that strongly contribute to the available near-surface atmospheric humidity. SLOE is particularly frequent along the warm ocean western boundary currents, downstream of large continental areas, and at the sea ice edge in polar regions with frequent cold-air outbreaks. Furthermore, wind-driven SLOE occurs in regions with topographically enforced winds. On a global annual average, SLOE occurs only 6% of the time but explains 22% of total ocean evaporation. An analysis of the past history and fate of air parcels involved in cold season SLOE in the North Atlantic and south Indian Oceans shows that cold-air advection is the main mechanism that induces these events. Extratropical cyclones thereby play an important role in setting the necessary equatorward synoptic flow. Consequently, the interannual variability of SLOE associated with the North Atlantic Oscillation and the southern annular mode reveals a very high sensitivity of SLOE with respect to the location of the storm tracks. This study highlights the strong link between transient synoptic events and the spatiotemporal variability in ocean evaporation patterns, which cannot be deduced from thermodynamic steadystate and climate mean state considerations alone.

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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Air-sea interaction, Evaporation, Extratropical cyclones, Hydrologic cycle, Water vapor
in
Journal of Climate
volume
31
issue
18
pages
26 pages
publisher
American Meteorological Society
external identifiers
  • scopus:85052964198
ISSN
0894-8755
DOI
10.1175/JCLI-D-17-0591.1
language
English
LU publication?
yes
id
e6857559-bb61-428d-a2d5-33b9e7041a0c
date added to LUP
2018-10-12 13:45:31
date last changed
2020-10-07 06:05:04
@article{e6857559-bb61-428d-a2d5-33b9e7041a0c,
  abstract     = {<p>This paper presents an object-based, global climatology (1979-2014) of strong large-scale ocean evaporation (SLOE) and its associated climatic properties. SLOE is diagnosed using an ''atmospheric moisture uptake efficiency'' criterion related to the ratio of surface evaporation and integrated water vapor content in the near-surface atmosphere. The chosen Eulerian identification procedure focuses on events that strongly contribute to the available near-surface atmospheric humidity. SLOE is particularly frequent along the warm ocean western boundary currents, downstream of large continental areas, and at the sea ice edge in polar regions with frequent cold-air outbreaks. Furthermore, wind-driven SLOE occurs in regions with topographically enforced winds. On a global annual average, SLOE occurs only 6% of the time but explains 22% of total ocean evaporation. An analysis of the past history and fate of air parcels involved in cold season SLOE in the North Atlantic and south Indian Oceans shows that cold-air advection is the main mechanism that induces these events. Extratropical cyclones thereby play an important role in setting the necessary equatorward synoptic flow. Consequently, the interannual variability of SLOE associated with the North Atlantic Oscillation and the southern annular mode reveals a very high sensitivity of SLOE with respect to the location of the storm tracks. This study highlights the strong link between transient synoptic events and the spatiotemporal variability in ocean evaporation patterns, which cannot be deduced from thermodynamic steadystate and climate mean state considerations alone.</p>},
  author       = {Aemisegger, Franziska and Papritz, Lukas},
  issn         = {0894-8755},
  language     = {eng},
  number       = {18},
  pages        = {7287--7312},
  publisher    = {American Meteorological Society},
  series       = {Journal of Climate},
  title        = {A climatology of strong large-scale ocean evaporation events. Part I : Identification, global distribution, and associated climate conditions},
  url          = {http://dx.doi.org/10.1175/JCLI-D-17-0591.1},
  doi          = {10.1175/JCLI-D-17-0591.1},
  volume       = {31},
  year         = {2018},
}