Separating the stratospheric and tropospheric pathways of El Niño–Southern Oscillation teleconnections
The El Niño–Southern Oscillation (ENSO) is a major driver of Northern Hemisphere wintertime variability and, generally, the key ingredient used in seasonal forecasts of wintertime surface climate. Modeling studies have recently suggested that ENSO teleconnections might involve both a tropospheric pa...
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ftcolumbiauniv:oai:academiccommons.columbia.edu:10.7916/D8CF9PXQ 2023-05-15T17:29:00+02:00 Separating the stratospheric and tropospheric pathways of El Niño–Southern Oscillation teleconnections Butler, Amy H. Polvani, Lorenzo M. Deser, Claira 2014 https://doi.org/10.7916/D8CF9PXQ English eng IOP Publishing https://doi.org/10.7916/D8CF9PXQ Tropospheric circulation Winter Air masses Atmospheric circulation Stratospheric circulation Atmosphere Meteorology Climatic changes Upper Articles 2014 ftcolumbiauniv https://doi.org/10.7916/D8CF9PXQ 2019-04-04T08:14:12Z The El Niño–Southern Oscillation (ENSO) is a major driver of Northern Hemisphere wintertime variability and, generally, the key ingredient used in seasonal forecasts of wintertime surface climate. Modeling studies have recently suggested that ENSO teleconnections might involve both a tropospheric pathway and a stratospheric one. Here, using reanalysis data, we carefully distinguish between the two. We first note that the temperature and circulation anomalies associated with the tropospheric pathway are nearly equal and opposite during the warm (El Niño) and cold (La Niña) phases of ENSO, whereas those associated with the stratospheric pathway are of the same sign, irrespective of the ENSO phase. We then exploit this fact to isolate the two pathways. Our decomposition reveals that ENSOs climate impacts over North America are largely associated with the tropospheric pathway, whereas ENSOs climate impacts over the North Atlantic and Eurasia are greatly affected by the stratospheric pathway. The stratospheric pathway, which we here define on the basis of the occurrence of one or more sudden stratospheric warmings in a given winter, and whose signature projects very strongly on the North Atlantic Oscillation, is found to be present 60% of the time during ENSO winters (of either phase): it therefore likely plays an important role in improving seasonal forecasts, notably over the North Atlantic and the Eurasian continent. Article in Journal/Newspaper North Atlantic North Atlantic oscillation Columbia University: Academic Commons |
institution |
Open Polar |
collection |
Columbia University: Academic Commons |
op_collection_id |
ftcolumbiauniv |
language |
English |
topic |
Tropospheric circulation Winter Air masses Atmospheric circulation Stratospheric circulation Atmosphere Meteorology Climatic changes Upper |
spellingShingle |
Tropospheric circulation Winter Air masses Atmospheric circulation Stratospheric circulation Atmosphere Meteorology Climatic changes Upper Butler, Amy H. Polvani, Lorenzo M. Deser, Claira Separating the stratospheric and tropospheric pathways of El Niño–Southern Oscillation teleconnections |
topic_facet |
Tropospheric circulation Winter Air masses Atmospheric circulation Stratospheric circulation Atmosphere Meteorology Climatic changes Upper |
description |
The El Niño–Southern Oscillation (ENSO) is a major driver of Northern Hemisphere wintertime variability and, generally, the key ingredient used in seasonal forecasts of wintertime surface climate. Modeling studies have recently suggested that ENSO teleconnections might involve both a tropospheric pathway and a stratospheric one. Here, using reanalysis data, we carefully distinguish between the two. We first note that the temperature and circulation anomalies associated with the tropospheric pathway are nearly equal and opposite during the warm (El Niño) and cold (La Niña) phases of ENSO, whereas those associated with the stratospheric pathway are of the same sign, irrespective of the ENSO phase. We then exploit this fact to isolate the two pathways. Our decomposition reveals that ENSOs climate impacts over North America are largely associated with the tropospheric pathway, whereas ENSOs climate impacts over the North Atlantic and Eurasia are greatly affected by the stratospheric pathway. The stratospheric pathway, which we here define on the basis of the occurrence of one or more sudden stratospheric warmings in a given winter, and whose signature projects very strongly on the North Atlantic Oscillation, is found to be present 60% of the time during ENSO winters (of either phase): it therefore likely plays an important role in improving seasonal forecasts, notably over the North Atlantic and the Eurasian continent. |
format |
Article in Journal/Newspaper |
author |
Butler, Amy H. Polvani, Lorenzo M. Deser, Claira |
author_facet |
Butler, Amy H. Polvani, Lorenzo M. Deser, Claira |
author_sort |
Butler, Amy H. |
title |
Separating the stratospheric and tropospheric pathways of El Niño–Southern Oscillation teleconnections |
title_short |
Separating the stratospheric and tropospheric pathways of El Niño–Southern Oscillation teleconnections |
title_full |
Separating the stratospheric and tropospheric pathways of El Niño–Southern Oscillation teleconnections |
title_fullStr |
Separating the stratospheric and tropospheric pathways of El Niño–Southern Oscillation teleconnections |
title_full_unstemmed |
Separating the stratospheric and tropospheric pathways of El Niño–Southern Oscillation teleconnections |
title_sort |
separating the stratospheric and tropospheric pathways of el niño–southern oscillation teleconnections |
publisher |
IOP Publishing |
publishDate |
2014 |
url |
https://doi.org/10.7916/D8CF9PXQ |
genre |
North Atlantic North Atlantic oscillation |
genre_facet |
North Atlantic North Atlantic oscillation |
op_relation |
https://doi.org/10.7916/D8CF9PXQ |
op_doi |
https://doi.org/10.7916/D8CF9PXQ |
_version_ |
1766122301747625984 |