Analysis of long‐term aerosol size distribution data from Jungfraujoch with emphasis on free tropospheric conditions, cloud influence, and air mass transport

Six years of aerosol size distribution measurements between 20 and 600 nm diameters and total aerosol concentration above 10 nm from March 2008 to February 2014 at the high‐alpine site Jungfraujoch are presented. The size distribution was found to be typically bimodal with mode diameters and widths relatively stable throughout the year and the observation period. New particle formation was observed on 14.5% of all days without a seasonal preference. Particles typically grew only into the Aitken mode and did not reach cloud condensation nucleus (CCN) sizes on the time scale of several days. Growth of preexisting particles in the Aitken mode, on average, contributed very few CCN. We concluded that the dominant fraction of CCN at Jungfraujoch originated in the boundary layer. A number of approaches were used to distinguish free tropospheric (FT) conditions and episodes with planetary boundary layer (PBL) influence. In the absence of PBL injections, the concentration of particles larger than 90 nm (N90, roughly corresponding to the CCN concentration) reached a value ~40 cm−3 while PBL influence caused N90 concentrations of several hundred or even 1000 cm−3. Comparing three criteria for free tropospheric conditions, we found FT prevalence for 39% of the time with over 60% during winter and below 20% during summer. It is noteworthy that a simple criterion based on standard trace gas measurements appeared to outperform alternative approaches.

Schlagwörter

Fachgebiet (DDC)

620 - Ingenieurwissenschaften und Maschinenbau

Projekt

Veranstaltung

Startdatum der Ausstellung

Enddatum der Ausstellung

Startdatum der Konferenz

Enddatum der Konferenz

Datum der letzten Prüfung

ISBN

ISSN

2169-897X
2169-8996

Sprache

Englisch

Während FHNW Zugehörigkeit erstellt

Ja

Zukunftsfelder FHNW

Publikationsstatus

Veröffentlicht

Begutachtung

Peer-Review der ganzen Publikation

Open Access-Status

Closed

Lizenz

Zitation

HERRMANN, Erik, Ernest WEINGARTNER, Stephan HENNE, Laurent VUILLEUMIER, Nicolas BUKOWIECKI, Martin STEINBACHER, Franz CONEN, Martine COLLAUD COEN, Emanuel HAMMER, Zsófia JURÁNYI, Urs BALTENSPERGER und Martin GYSEL, 2015. Analysis of long‐term aerosol size distribution data from Jungfraujoch with emphasis on free tropospheric conditions, cloud influence, and air mass transport. Journal of Geophysical Research: Atmospheres. 2015. Bd. 120, Nr. 18, S. 9459–9480. DOI 10.1002/2015jd023660. Verfügbar unter: https://irf.fhnw.ch/handle/11654/44276

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