 |
| Titel |
Mass analysis of charged aerosol particles in NLC and PMSE during the ECOMA/MASS campaign |
| VerfasserIn |
S. Robertson, M. Horányi, S. Knappmiller, Z. Sternovsky, R. Holzworth, M. Shimogawa, M. Friedrich, K. Torkar, J. Gumbel, L. Megner, G. Baumgarten, R. Latteck, M. Rapp, U.-P. Hoppe, M. E. Hervig |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
0992-7689
|
| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 27, no. 3 ; Nr. 27, no. 3 (2009-03-12), S.1213-1232 |
| Datensatznummer |
250016451
|
| Publikation (Nr.) |
 copernicus.org/angeo-27-1213-2009.pdf |
|
|
|
|
|
| Zusammenfassung |
| MASS (Mesospheric Aerosol Sampling Spectrometer) is a
multichannel mass spectrometer for charged aerosol particles, which was
flown from the Andøya Rocket Range, Norway, through NLC and PMSE on 3
August 2007 and through PMSE on 6 August 2007. The eight-channel analyzers
provided for the first time simultaneous measurements of the charge density
residing on aerosol particles in four mass ranges, corresponding to ice
particles with radii <0.5 nm (including ions), 0.5–1 nm, 1–2 nm,
and >3 nm (approximately). Positive and negative particles were recorded
on separate channels. Faraday rotation measurements provided electron
density and a means of checking charge density measurements made by the
spectrometer. Additional complementary measurements were made by
rocket-borne dust impact detectors, electric field booms, a photometer and
ground-based radar and lidar. The MASS data from the first flight showed
negative charge number densities of 1500–3000 cm−3 for particles
with radii >3 nm from 83–88 km approximately coincident with PMSE
observed by the ALWIN radar and NLC observed by the ALOMAR lidar. For
particles in the 1–2 nm range, number densities of positive and negative
charge were similar in magnitude (~2000 cm−3) and for smaller
particles, 0.5–1 nm in radius, positive charge was dominant. The
occurrence of positive charge on the aerosol particles of the smallest size
and predominately negative charge on the particles of largest size suggests
that nucleation occurs on positive condensation nuclei and is followed by
collection of negative charge during subsequent growth to larger size.
Faraday rotation measurements show a bite-out in electron density that
increases the time for positive aerosol particles to be neutralized and
charged negatively. The larger particles (>3 nm) are observed throughout
the NLC region, 83–88 km, and the smaller particles are observed
primarily at the high end of the range, 86–88 km. The second flight into
PMSE alone at 84–88 km, found only small number densities (~500 cm−3)
of particles >3 nm in a narrow altitude range, 86.5–87.5 km. Both positive (~2000 cm−3)
and negative (~4500 cm−3) particles with radii 1–2 nm were detected from 85–87.5 km. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|