Hygroscopic properties of the ambient aerosol in southern Sweden - a two year study
Fors, Erik LU ; Swietlicki, Erik LU
; Svenningsson, Birgitta
LU
; Kristensson, Adam
LU
; Frank, Göran
LU
and Sporre, Moa
LU
(2011)
In Atmospheric Chemistry and Physics
11(16).
p.8343-8361
- Abstract
- The hygroscopic growth of the atmospheric aerosol is a critical parameter for quantifying the anthropogenic radiative forcing. Until now, there has been a lack of long term measurements due to limitations in instrumental techniques. In this work, for the first time the seasonal variation of the hygroscopic properties of a continental background aerosol has been described, based on more than two years of continuous measurements. In addition to this, the diurnal variation of the hygroscopic growth has been investigated, as well as the seasonal variation in CCN concentration. These physical properties of the aerosol have been measured with a Hygroscopic Tandem Differential Mobility Analyzer (H-TDMA), a Differential Mobility Particle Sizer... (More)
- The hygroscopic growth of the atmospheric aerosol is a critical parameter for quantifying the anthropogenic radiative forcing. Until now, there has been a lack of long term measurements due to limitations in instrumental techniques. In this work, for the first time the seasonal variation of the hygroscopic properties of a continental background aerosol has been described, based on more than two years of continuous measurements. In addition to this, the diurnal variation of the hygroscopic growth has been investigated, as well as the seasonal variation in CCN concentration. These physical properties of the aerosol have been measured with a Hygroscopic Tandem Differential Mobility Analyzer (H-TDMA), a Differential Mobility Particle Sizer (DMPS), and a Cloud Condensation Nuclei Counter (CCNC). The results show that smaller particles are generally less hygroscopic than larger ones, and that there is a clear difference in the hygroscopic properties between the Aitken and the accumulation mode. A seasonal cycle was found for all particle sizes. In general, the average hygroscopic growth is lower during wintertime, due to an increase in the relative abundance of less hygroscopic or barely hygroscopic particles. Monthly averages showed that the hygroscopic growth factors of the two dominating hygroscopic modes (one barely hygroscopic and one more hygroscopic) were relatively stable. The hygroscopic growth additionally showed a diurnal cycle, with higher growth factors during day time. CCN predictions based on H-TDMA data underpredicted the activated CCN number concentration with 7% for a 1% water supersaturation ratio. The underprediction increases with decreasing s, most likely due to a combination of measurement and modeling uncertainties. It was found that although the aerosol is often externally mixed, recalculating to an internal mixture with respect to hygroscopicity did not change the CCN concentration as a function of supersaturation significantly. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/2160767
- author
- Fors, Erik
LU
; Swietlicki, Erik
LU
; Svenningsson, Birgitta
LU
; Kristensson, Adam
LU
; Frank, Göran
LU
and Sporre, Moa
LU
- organization
- publishing date
- 2011
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Atmospheric Chemistry and Physics
- volume
- 11
- issue
- 16
- pages
- 8343 - 8361
- publisher
- Copernicus GmbH
- external identifiers
-
- wos:000294406300008
- scopus:80051753641
- ISSN
- 1680-7324
- DOI
- 10.5194/acp-11-8343-2011
- language
- English
- LU publication?
- yes
- additional info
- The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Nuclear Physics (Faculty of Technology) (011013007)
- id
- a639424e-bdce-4f5b-a6c3-c351615c63b1 (old id 2160767)
- date added to LUP
- 2016-04-01 10:59:16
- date last changed
- 2022-05-25 08:38:49
@article{a639424e-bdce-4f5b-a6c3-c351615c63b1,
abstract = {{The hygroscopic growth of the atmospheric aerosol is a critical parameter for quantifying the anthropogenic radiative forcing. Until now, there has been a lack of long term measurements due to limitations in instrumental techniques. In this work, for the first time the seasonal variation of the hygroscopic properties of a continental background aerosol has been described, based on more than two years of continuous measurements. In addition to this, the diurnal variation of the hygroscopic growth has been investigated, as well as the seasonal variation in CCN concentration. These physical properties of the aerosol have been measured with a Hygroscopic Tandem Differential Mobility Analyzer (H-TDMA), a Differential Mobility Particle Sizer (DMPS), and a Cloud Condensation Nuclei Counter (CCNC). The results show that smaller particles are generally less hygroscopic than larger ones, and that there is a clear difference in the hygroscopic properties between the Aitken and the accumulation mode. A seasonal cycle was found for all particle sizes. In general, the average hygroscopic growth is lower during wintertime, due to an increase in the relative abundance of less hygroscopic or barely hygroscopic particles. Monthly averages showed that the hygroscopic growth factors of the two dominating hygroscopic modes (one barely hygroscopic and one more hygroscopic) were relatively stable. The hygroscopic growth additionally showed a diurnal cycle, with higher growth factors during day time. CCN predictions based on H-TDMA data underpredicted the activated CCN number concentration with 7% for a 1% water supersaturation ratio. The underprediction increases with decreasing s, most likely due to a combination of measurement and modeling uncertainties. It was found that although the aerosol is often externally mixed, recalculating to an internal mixture with respect to hygroscopicity did not change the CCN concentration as a function of supersaturation significantly.}},
author = {{Fors, Erik and Swietlicki, Erik and Svenningsson, Birgitta and Kristensson, Adam and Frank, Göran and Sporre, Moa}},
issn = {{1680-7324}},
language = {{eng}},
number = {{16}},
pages = {{8343--8361}},
publisher = {{Copernicus GmbH}},
series = {{Atmospheric Chemistry and Physics}},
title = {{Hygroscopic properties of the ambient aerosol in southern Sweden - a two year study}},
url = {{http://dx.doi.org/10.5194/acp-11-8343-2011}},
doi = {{10.5194/acp-11-8343-2011}},
volume = {{11}},
year = {{2011}},
}