Quasi-horizontal transport of Asian summer monsoon air during the PHILEAS campaign in summer and autumn 2023

Publikationstyp:
Sonstiges
Metadaten:
Abstract
<jats:p>The Asian summer monsoon provides a strong link between the near-surface pollution and the global atmosphere by connecting local sources at the surface with the large-scale circulation. It affects both the composition of the deep stratosphere and of the extratropical lowermost stratosphere (LMS). To evaluate the associated global effects on climate, a detailed understanding of the associated pathways is essential. The extratropical upper troposphere / lower stratosphere (UT/LS) is mainly influenced by quasi-horizontal export of polluted and moist air from the upper-level Asian Monsoon anticyclone (AMA), which is facilitated by regular eddy shedding events. Currently, there is a lack of observations in the northern hemisphere transition area at middle and high latitudes where the dissolution and filamentation of the shed eddies and subsequent mixing into the lower stratosphere takes place. The recent HALO campaign PHILEAS (Probing high latitude export of air from the Asian summer monsoon) aimed to fill this important gap by dedicated aircraft observations from Anchorage/Alaska and Oberpfaffenhofen/Germany in summer and autumn 2023. Our presentation puts the PHILEAS campaign in a climatological context. We compare the special meteorological situation as well as model simulations of tracers of air mass origin and transit time distributions in the monsoon season 2023 (e.g. South Asia) with the respective long-year average (2000 to 2020). We analyse recurrent meteorological situations that favour the transport of AMA air to high latitudes and quantify the composition of these air masses exported from the AMA with air from different surface source regions and the related transport time scales. Based on this analysis we investigate whether the Asian summer monsoon anticyclone in 2023 and its impact on the northern extra-tropical lower stratosphere represents typical climatological conditions or stands out. Selected results from the aircraft measurements during the PHILEAS campaign are presented and discussed in light of particular meteorological situations.</jats:p>
Autoren
  • Martin Riese
  • Peter Hoor
  • Christian Rolf
  • Daniel Kunkel
DOI
10.5194/egusphere-egu24-6647
Buchtitel
Copernicus GmbH
Datum der Veröffentlichung
2024
Status
Published
Herausgeber URL
http://dx.doi.org/10.5194/egusphere-egu24-6647
Datum der Datenerfassung
2024
Titel
Quasi-horizontal transport of Asian summer monsoon air during the PHILEAS campaign in summer and autumn 2023

Datenquelle: Crossref

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