Characterization of transport from the Asian summer monsoon anticyclone into the UTLS via shedding of low-potential vorticity cutoffs
Air mass transport within the summertime Asian monsoon circulation provides a major source of anthropogenic pollution for the upper troposphere and lower stratosphere (UTLS). Here, we investigate the quasi-horizontal transport of air masses from the Asian summer monsoon anticyclone (ASMA) into the e...
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ftcopernicus:oai:publications.copernicus.org:acpd98790 2023-05-15T18:49:00+02:00 Characterization of transport from the Asian summer monsoon anticyclone into the UTLS via shedding of low-potential vorticity cutoffs Clemens, Jan Ploeger, Felix Konopka, Paul Portmann, Raphael Sprenger, Michael Wernli, Heini 2021-11-03 application/pdf https://doi.org/10.5194/acp-2021-905 https://acp.copernicus.org/preprints/acp-2021-905/ eng eng doi:10.5194/acp-2021-905 https://acp.copernicus.org/preprints/acp-2021-905/ eISSN: 1680-7324 Text 2021 ftcopernicus https://doi.org/10.5194/acp-2021-905 2021-11-08T17:22:29Z Air mass transport within the summertime Asian monsoon circulation provides a major source of anthropogenic pollution for the upper troposphere and lower stratosphere (UTLS). Here, we investigate the quasi-horizontal transport of air masses from the Asian summer monsoon anticyclone (ASMA) into the extratropical lower stratosphere and their chemical evolution. For that reason, we developed a method to identify and track the air masses exported from the monsoon. This method is based on the anomalously low potential vorticity (PV) of these air masses (tropospheric low–PV cutoffs) compared to the lower-stratosphere, and uses trajectory calculations and chemical fields from the Chemical Lagrangian Model of the Stratosphere (CLaMS). The results show evidence for frequent summertime transport from the monsoon anticyclone to mid-latitudes over the North Pacific, even reaching high latitude regions of Siberia and Alaska. Most of the low–PV cutoffs related to air masses exported from the ASMA have lifetimes shorter than one week (about 90 %) and sizes smaller than 1 percent of the northern hemisphere (NH) area. The chemical composition of these air masses is characterised by carbon monoxide, ozone and water vapour mixing ratios at an intermediate range between values typical for the monsoon anticyclone and the lower-stratosphere. The chemical evolution during transport within these low–PV cutoffs shows a gradual change from characteristics of the monsoon anticyclone to characteristics of the lower stratospheric background during about one week, indicating continuous mixing with the background atmosphere. Text Alaska Siberia Copernicus Publications: E-Journals Pacific |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
Air mass transport within the summertime Asian monsoon circulation provides a major source of anthropogenic pollution for the upper troposphere and lower stratosphere (UTLS). Here, we investigate the quasi-horizontal transport of air masses from the Asian summer monsoon anticyclone (ASMA) into the extratropical lower stratosphere and their chemical evolution. For that reason, we developed a method to identify and track the air masses exported from the monsoon. This method is based on the anomalously low potential vorticity (PV) of these air masses (tropospheric low–PV cutoffs) compared to the lower-stratosphere, and uses trajectory calculations and chemical fields from the Chemical Lagrangian Model of the Stratosphere (CLaMS). The results show evidence for frequent summertime transport from the monsoon anticyclone to mid-latitudes over the North Pacific, even reaching high latitude regions of Siberia and Alaska. Most of the low–PV cutoffs related to air masses exported from the ASMA have lifetimes shorter than one week (about 90 %) and sizes smaller than 1 percent of the northern hemisphere (NH) area. The chemical composition of these air masses is characterised by carbon monoxide, ozone and water vapour mixing ratios at an intermediate range between values typical for the monsoon anticyclone and the lower-stratosphere. The chemical evolution during transport within these low–PV cutoffs shows a gradual change from characteristics of the monsoon anticyclone to characteristics of the lower stratospheric background during about one week, indicating continuous mixing with the background atmosphere. |
format |
Text |
author |
Clemens, Jan Ploeger, Felix Konopka, Paul Portmann, Raphael Sprenger, Michael Wernli, Heini |
spellingShingle |
Clemens, Jan Ploeger, Felix Konopka, Paul Portmann, Raphael Sprenger, Michael Wernli, Heini Characterization of transport from the Asian summer monsoon anticyclone into the UTLS via shedding of low-potential vorticity cutoffs |
author_facet |
Clemens, Jan Ploeger, Felix Konopka, Paul Portmann, Raphael Sprenger, Michael Wernli, Heini |
author_sort |
Clemens, Jan |
title |
Characterization of transport from the Asian summer monsoon anticyclone into the UTLS via shedding of low-potential vorticity cutoffs |
title_short |
Characterization of transport from the Asian summer monsoon anticyclone into the UTLS via shedding of low-potential vorticity cutoffs |
title_full |
Characterization of transport from the Asian summer monsoon anticyclone into the UTLS via shedding of low-potential vorticity cutoffs |
title_fullStr |
Characterization of transport from the Asian summer monsoon anticyclone into the UTLS via shedding of low-potential vorticity cutoffs |
title_full_unstemmed |
Characterization of transport from the Asian summer monsoon anticyclone into the UTLS via shedding of low-potential vorticity cutoffs |
title_sort |
characterization of transport from the asian summer monsoon anticyclone into the utls via shedding of low-potential vorticity cutoffs |
publishDate |
2021 |
url |
https://doi.org/10.5194/acp-2021-905 https://acp.copernicus.org/preprints/acp-2021-905/ |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
Alaska Siberia |
genre_facet |
Alaska Siberia |
op_source |
eISSN: 1680-7324 |
op_relation |
doi:10.5194/acp-2021-905 https://acp.copernicus.org/preprints/acp-2021-905/ |
op_doi |
https://doi.org/10.5194/acp-2021-905 |
_version_ |
1766242410327703552 |