 |
| Titel |
Tropospheric aerosol scattering and absorption over central Europe: a closure study for the dry particle state |
| VerfasserIn |
N. Ma, W. Birmili, T. Müller, T. Tuch, Y. F. Cheng, W. Y. Xu, C. S. Zhao, A. Wiedensohler |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 12 ; Nr. 14, no. 12 (2014-06-24), S.6241-6259 |
| Datensatznummer |
250118830
|
| Publikation (Nr.) |
 copernicus.org/acp-14-6241-2014.pdf |
|
|
|
|
|
| Zusammenfassung |
This work analyses optical properties of the dry tropospheric aerosol
measured at the regional Global Atmosphere Watch (GAW) observation site Melpitz in East Germany. For a
continuous observation period between 2007 and 2010, we provide
representative values of the dry-state scattering coefficient, hemispheric
backscattering coefficient, absorption coefficient, single scattering
albedo, and scattering Ångström exponent. Besides the direct
measurement, the aerosol scattering coefficient was alternatively computed
from experimental particle number size distributions using a Mie model.
Within pre-defined limits, a closure could be achieved with the direct
measurement. The achievement of closure implies that such calculations can
be used as a high-level quality control measure for data sets involving
multiple instrumentation.
All dry-state optical properties show pronounced annual and diurnal
variations, which are attributed to the corresponding variations in the
regional emission fluxes, the intensity of secondary particle formation, and
the mixing layer height. Air mass classification shows that atmospheric
stability is a major factor influencing the dry aerosol properties at the
GAW station. In the cold season, temperature inversions limit the volume
available for atmospheric mixing, so that the dry-state aerosol optical
properties near the ground proved quite sensitive to the geographical origin
of the air mass. In the warm season, when the atmosphere is usually
well-mixed during daytime, considerably less variability was observed for
the optical properties between different air masses. This work provides, on
the basis of quality-checked in situ measurements, a first step towards a
climatological assessment of direct aerosol radiative forcing in the region
under study. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|