A ‘warm path’ for Gulf Stream–troposphere interactions
Warm advection by the Gulf Stream creates a characteristic ‘tongue’ of warm water leaving a strong imprint on the sea surface temperature (SST) distribution in the western North Atlantic. This study aims at quantifying the climatological impact of this feature on cyclones travelling across this regi...
Published in: | Tellus A: Dynamic Meteorology and Oceanography |
---|---|
Main Authors: | , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Stockholm University Press
2017
|
Subjects: | |
Online Access: | https://doi.org/10.1080/16000870.2017.1299397 https://doaj.org/article/77575e53f3034747baedb7a09035736c |
id |
ftdoajarticles:oai:doaj.org/article:77575e53f3034747baedb7a09035736c |
---|---|
record_format |
openpolar |
spelling |
ftdoajarticles:oai:doaj.org/article:77575e53f3034747baedb7a09035736c 2023-05-15T17:31:32+02:00 A ‘warm path’ for Gulf Stream–troposphere interactions Luke Sheldon Arnaud Czaja Benoit Vannière Cyril Morcrette Benoit Sohet Mathieu Casado Doug Smith 2017-01-01T00:00:00Z https://doi.org/10.1080/16000870.2017.1299397 https://doaj.org/article/77575e53f3034747baedb7a09035736c EN eng Stockholm University Press http://dx.doi.org/10.1080/16000870.2017.1299397 https://doaj.org/toc/1600-0870 1600-0870 doi:10.1080/16000870.2017.1299397 https://doaj.org/article/77575e53f3034747baedb7a09035736c Tellus: Series A, Dynamic Meteorology and Oceanography, Vol 69, Iss 1 (2017) ocean–atmosphere interactions Gulf Stream climate dynamics Oceanography GC1-1581 Meteorology. Climatology QC851-999 article 2017 ftdoajarticles https://doi.org/10.1080/16000870.2017.1299397 2022-12-30T22:33:10Z Warm advection by the Gulf Stream creates a characteristic ‘tongue’ of warm water leaving a strong imprint on the sea surface temperature (SST) distribution in the western North Atlantic. This study aims at quantifying the climatological impact of this feature on cyclones travelling across this region in winter using a combination of reanalysis data and numerical experiments. It is suggested that the Gulf Stream ‘warm tongue’ is conducive to enhanced upward motion in cyclones because (i) it helps maintain a high equivalent potential temperature of air parcels at low levels which favors deep ascent in the warm conveyor belt of cyclones and (ii) because the large SST gradients to the north of the warm tongue drive a thermally direct circulation reinforcing and, possibly, destabilizing, the transverse circulation embedded in cyclones. This hypothesis is confirmed by comparing simulations at 12 km resolution from the Met Office Unified Model forced with realistic SST distribution to simulations with an SST distribution from which the Gulf Stream warm tongue was artificially removed or made colder by $ 3\,^\circ \mathrm{C} $. It is also supported by a dynamical diagnostic applied to the ERA interim data-set over the wintertime period (1979–2012). The mechanism of oceanic forcing highlighted in this study is associated with near thermal equilibration of low level air masses with SST in the warm sector of cyclones passing over the Gulf Stream warm tongue, which is in sharp contrast to what occurs in their cold sector. It is suggested that this ‘warm path’ for the climatic impact of the Gulf Stream on the North Atlantic storm-track is not currently represented in climate models because of their coarse horizontal resolution. Article in Journal/Newspaper North Atlantic Directory of Open Access Journals: DOAJ Articles Tellus A: Dynamic Meteorology and Oceanography 69 1 1299397 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
ocean–atmosphere interactions Gulf Stream climate dynamics Oceanography GC1-1581 Meteorology. Climatology QC851-999 |
spellingShingle |
ocean–atmosphere interactions Gulf Stream climate dynamics Oceanography GC1-1581 Meteorology. Climatology QC851-999 Luke Sheldon Arnaud Czaja Benoit Vannière Cyril Morcrette Benoit Sohet Mathieu Casado Doug Smith A ‘warm path’ for Gulf Stream–troposphere interactions |
topic_facet |
ocean–atmosphere interactions Gulf Stream climate dynamics Oceanography GC1-1581 Meteorology. Climatology QC851-999 |
description |
Warm advection by the Gulf Stream creates a characteristic ‘tongue’ of warm water leaving a strong imprint on the sea surface temperature (SST) distribution in the western North Atlantic. This study aims at quantifying the climatological impact of this feature on cyclones travelling across this region in winter using a combination of reanalysis data and numerical experiments. It is suggested that the Gulf Stream ‘warm tongue’ is conducive to enhanced upward motion in cyclones because (i) it helps maintain a high equivalent potential temperature of air parcels at low levels which favors deep ascent in the warm conveyor belt of cyclones and (ii) because the large SST gradients to the north of the warm tongue drive a thermally direct circulation reinforcing and, possibly, destabilizing, the transverse circulation embedded in cyclones. This hypothesis is confirmed by comparing simulations at 12 km resolution from the Met Office Unified Model forced with realistic SST distribution to simulations with an SST distribution from which the Gulf Stream warm tongue was artificially removed or made colder by $ 3\,^\circ \mathrm{C} $. It is also supported by a dynamical diagnostic applied to the ERA interim data-set over the wintertime period (1979–2012). The mechanism of oceanic forcing highlighted in this study is associated with near thermal equilibration of low level air masses with SST in the warm sector of cyclones passing over the Gulf Stream warm tongue, which is in sharp contrast to what occurs in their cold sector. It is suggested that this ‘warm path’ for the climatic impact of the Gulf Stream on the North Atlantic storm-track is not currently represented in climate models because of their coarse horizontal resolution. |
format |
Article in Journal/Newspaper |
author |
Luke Sheldon Arnaud Czaja Benoit Vannière Cyril Morcrette Benoit Sohet Mathieu Casado Doug Smith |
author_facet |
Luke Sheldon Arnaud Czaja Benoit Vannière Cyril Morcrette Benoit Sohet Mathieu Casado Doug Smith |
author_sort |
Luke Sheldon |
title |
A ‘warm path’ for Gulf Stream–troposphere interactions |
title_short |
A ‘warm path’ for Gulf Stream–troposphere interactions |
title_full |
A ‘warm path’ for Gulf Stream–troposphere interactions |
title_fullStr |
A ‘warm path’ for Gulf Stream–troposphere interactions |
title_full_unstemmed |
A ‘warm path’ for Gulf Stream–troposphere interactions |
title_sort |
‘warm path’ for gulf stream–troposphere interactions |
publisher |
Stockholm University Press |
publishDate |
2017 |
url |
https://doi.org/10.1080/16000870.2017.1299397 https://doaj.org/article/77575e53f3034747baedb7a09035736c |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Tellus: Series A, Dynamic Meteorology and Oceanography, Vol 69, Iss 1 (2017) |
op_relation |
http://dx.doi.org/10.1080/16000870.2017.1299397 https://doaj.org/toc/1600-0870 1600-0870 doi:10.1080/16000870.2017.1299397 https://doaj.org/article/77575e53f3034747baedb7a09035736c |
op_doi |
https://doi.org/10.1080/16000870.2017.1299397 |
container_title |
Tellus A: Dynamic Meteorology and Oceanography |
container_volume |
69 |
container_issue |
1 |
container_start_page |
1299397 |
_version_ |
1766129167433203712 |