In situ observation of new particle formation (NPF) in the tropical tropopause layer of the 2017 Asian monsoon anticyclone - Part 1: Summary of StratoClim results

Publication type:
Journal article
Metadata:
Autoren
  • Ralf Weigel
  • Christoph Mahnke
  • Manuel Baumgartner
  • Antonis Dragoneas
  • Baerbel Vogel
  • Felix Ploeger
  • Silvia Viciani
  • Francesco D'Amato
  • Silvia Bucci
  • Bernard Legras
  • Beiping Luo
  • Stephan Borrmann
Autoren-URL
https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=fis-test-1&SrcAuth=WosAPI&KeyUT=WOS:000683773600002&DestLinkType=FullRecord&DestApp=WOS_CPL
DOI
10.5194/acp-21-11689-2021
eISSN
1680-7324
Externe Identifier
  • Clarivate Analytics Document Solution ID: TY4RP
ISSN
1680-7316
Ausgabe der Veröffentlichung
15
Zeitschrift
ATMOSPHERIC CHEMISTRY AND PHYSICS
Paginierung
11689 - 11722
Datum der Veröffentlichung
2021
Status
Published
Titel
In situ observation of new particle formation (NPF) in the tropical tropopause layer of the 2017 Asian monsoon anticyclone - Part 1: Summary of StratoClim results
Sub types
  • Article
Ausgabe der Zeitschrift
21

Data source: Web of Science (Lite)

Other metadata sources:
Abstract
<jats:p>Abstract. During the monsoon season of the year 2017 the airborne StratoClim mission took place in Kathmandu, Nepal, with eight mission flights of the M-55 Geophysica in the upper troposphere–lower stratosphere (UTLS) of the Asian monsoon anticyclone (AMA) over northern India, Nepal, and Bangladesh. More than 100 events of new particle formation (NPF) were observed. In total, more than 2 h of flight time was spent under NPF conditions as indicated by the abundant presence of nucleation-mode aerosols, i.e. with particle diameters dp smaller than 15 nm, which were detected in situ by means of condensation nuclei counting techniques. Mixing ratios of nucleation-mode particles (nnm) of up to ∼ 50 000 mg−1 were measured at heights of 15–16 km (θ ≈ 370 K). NPF was most frequently observed at ∼ 12–16 km altitude (θ ≈ 355–380 K) and mainly below the tropopause. Resulting nnm remained elevated (∼ 300–2000 mg−1) up to altitudes of ∼ 17.5 km (θ ≈ 400 K), while under NPF conditions the fraction (f) of sub-micrometre-sized non-volatile residues (dp &gt; 10 nm) remained below 50 %. At ∼ 12–14 km (θ ≈ 355–365 K) the minimum of f (&lt; 15 %) was found, and underneath, the median f generally remains below 25 %. The persistence of particles at nucleation-mode sizes is limited to a few hours, mainly due to coagulation, as demonstrated by a numerical simulation. The frequency of NPF events observed during StratoClim 2017 underlines the importance of the AMA as a source region for UTLS aerosols and for the formation and maintenance of the Asian tropopause aerosol layer (ATAL). The observed abundance of NPF-produced nucleation-mode particles within the AMA is not unambiguously attributable to (a) specific source regions in the boundary layer (according to backward trajectory analyses), or (b) the direct supply with precursor material by convective updraught (from correlations of NPF with carbon monoxide), or (c) the recent release of NPF-capable material from the convective outflow (according to air mass transport times in the tropical tropopause layer, TTL). Temperature anomalies with ΔT of 2 K (peak-to-peak amplitude), as observed at a horizontal wavelength of ∼ 70–100 km during a level flight of several hours, match with NPF detections and represent an additional mechanism for local increases in supersaturation of the NPF precursors. Effective precursor supply and widely distributed temperature anomalies within the AMA can explain the higher frequency of intense NPF observed during StratoClim 2017 than all previous NPF detections with COPAS (COndensation PArticle counting System) at TTL levels over Brazil, northern Australia, or West Africa. </jats:p>
Autoren
  • Ralf Weigel
  • Christoph Mahnke
  • Manuel Baumgartner
  • Antonis Dragoneas
  • Bärbel Vogel
  • Felix Ploeger
  • Silvia Viciani
  • Francesco D'Amato
  • Silvia Bucci
  • Bernard Legras
  • Beiping Luo
  • Stephan Borrmann
DOI
10.5194/acp-21-11689-2021
eISSN
1680-7324
Ausgabe der Veröffentlichung
15
Zeitschrift
Atmospheric Chemistry and Physics
Sprache
en
Online publication date
2021
Paginierung
11689 - 11722
Status
Published online
Herausgeber
Copernicus GmbH
Herausgeber URL
http://dx.doi.org/10.5194/acp-21-11689-2021
Datum der Datenerfassung
2021
Titel
In situ observation of new particle formation (NPF) in the tropical tropopause layer of the 2017 Asian monsoon anticyclone – Part 1: Summary of StratoClim results
Ausgabe der Zeitschrift
21

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