Sensitivity of transatlantic dust transport to chemical aging and related atmospheric processes

Publikationstyp:
Zeitschriftenaufsatz
Metadaten:
Autoren
  • Mohamed Abdelkader
  • Swen Metzger
  • Benedikt Steil
  • Klaus Klingmueller
  • Holger Tost
  • Andrea Pozzer
  • Georgiy Stenchikov
  • Leonard Barrie
  • Jos Lelieveld
Autoren-URL
https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=fis-test-1&SrcAuth=WosAPI&KeyUT=WOS:000397932200002&DestLinkType=FullRecord&DestApp=WOS_CPL
DOI
10.5194/acp-17-3799-2017
eISSN
1680-7324
Externe Identifier
  • Clarivate Analytics Document Solution ID: EQ2WO
ISSN
1680-7316
Ausgabe der Veröffentlichung
6
Zeitschrift
ATMOSPHERIC CHEMISTRY AND PHYSICS
Paginierung
3799 - 3821
Datum der Veröffentlichung
2017
Status
Published
Titel
Sensitivity of transatlantic dust transport to chemical aging and related atmospheric processes
Sub types
  • Article
Ausgabe der Zeitschrift
17

Datenquelle: Web of Science (Lite)

Andere Metadatenquellen:
Abstract
<jats:p>Abstract. We present a sensitivity study on transatlantic dust transport, a process which has many implications for the atmosphere, the ocean and the climate. We investigate the impact of key processes that control the dust outflow, i.e., the emission flux, convection schemes and the chemical aging of mineral dust, by using the EMAC model following Abdelkader et al. (2015). To characterize the dust outflow over the Atlantic Ocean, we distinguish two geographic zones: (i) dust interactions within the Intertropical Convergence Zone (ITCZ), or the dust–ITCZ interaction zone (DIZ), and (ii) the adjacent dust transport over the Atlantic Ocean (DTA) zone. In the latter zone, the dust loading shows a steep and linear gradient westward over the Atlantic Ocean since particle sedimentation is the dominant removal process, whereas in the DIZ zone aerosol–cloud interactions, wet deposition and scavenging processes determine the extent of the dust outflow. Generally, the EMAC simulated dust compares well with CALIPSO observations; however, our reference model configuration tends to overestimate the dust extinction at a lower elevation and underestimates it at a higher elevation. The aerosol optical depth (AOD) over the Caribbean responds to the dust emission flux only when the emitted dust mass is significantly increased over the source region in Africa by a factor of 10. These findings point to the dominant role of dust removal (especially wet deposition) in transatlantic dust transport. Experiments with different convection schemes have indeed revealed that the transatlantic dust transport is more sensitive to the convection scheme than to the dust emission flux parameterization. To study the impact of dust chemical aging, we focus on a major dust outflow in July 2009. We use the calcium cation as a proxy for the overall chemical reactive dust fraction and consider the uptake of major inorganic acids (i.e., H2SO4, HNO3 and HCl) and their anions, i.e., sulfate (SO42−), bisulfate (HSO4−), nitrate (NO3−) and chloride (Cl−), on the surface of mineral particles. The subsequent neutralization reactions with the calcium cation form various salt compounds that cause the uptake of water vapor from the atmosphere, i.e., through the chemical aging of dust particles leading to an increase of 0.15 in the AOD under subsaturated conditions (July 2009 monthly mean). As a result of the radiative feedback on surface winds, dust emissions increased regionally. On the other hand, the aged dust particles, compared to the non-aged particles, are more efficiently removed by both wet and dry deposition due to the increased hygroscopicity and particle size (mainly due to water uptake). The enhanced removal of aged particles decreases the dust burden and lifetime, which indirectly reduces the dust AOD by 0.05 (monthly mean). Both processes can be significant (major dust outflow, July 2009), but the net effect depends on the region and level of dust chemical aging. </jats:p>
Autoren
  • Mohamed Abdelkader
  • Swen Metzger
  • Benedikt Steil
  • Klaus Klingmüller
  • Holger Tost
  • Andrea Pozzer
  • Georgiy Stenchikov
  • Leonard Barrie
  • Jos Lelieveld
DOI
10.5194/acp-17-3799-2017
eISSN
1680-7324
Ausgabe der Veröffentlichung
6
Zeitschrift
Atmospheric Chemistry and Physics
Sprache
en
Online publication date
2017
Paginierung
3799 - 3821
Status
Published online
Herausgeber
Copernicus GmbH
Herausgeber URL
http://dx.doi.org/10.5194/acp-17-3799-2017
Datum der Datenerfassung
2021
Titel
Sensitivity of transatlantic dust transport to chemical aging and related atmospheric processes
Ausgabe der Zeitschrift
17

Datenquelle: Crossref

Beziehungen:
Hat Preprint
Eigentum von

Werkzeuge