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| Titel |
Combined MIPAS (airborne/satellite), CALIPSO and in situ study on large potential NAT particles observed in early Arctic winter stratosphere in December 2011 |
| VerfasserIn |
Wolfgang Woiwode, Michael Höpfner, Michael Pitts, Lamont Poole, Hermann Oelhaf, Sergej Molleker, Stephan Borrmann, Andreas Ebersoldt, Wiebke Frey, Thomas Gulde, Guido Maucher, Christof Piesch, Christian Sartorius, Johannes Orphal |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250107470
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| Publikation (Nr.) |
 EGU/EGU2015-7175.pdf |
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| Zusammenfassung |
| The understanding of the characteristics of large HNO3-containing particles (potential
‘NAT-rocks’) involved in vertical redistribution of HNO3 in the polar winter stratosphere is
limited due to the difficult accessibility of these particles by observations. While robust
polar stratospheric cloud (PSC) classification schemes exist for observations by the
space-borne lidar aboard CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder
Satellite Observations) as well as for the passive mid-infrared limb observations
by MIPAS (Michelson Interferometer for Passive Atmospheric Sounding), these
observations are hardly exploited for the detection of large (diameter >10 μm) NAT
particles. This is due to the facts that these particles have low overall number densities,
resulting in weak detectable signatures, and that the physical characteristics of these
particles (i.e. shape, morphology, HNO3-content and optical characteristics) are
uncertain.
We investigate collocated and complementary observations of a low-density potential
large NAT particle field by the space-borne instruments CALIPSO and MIPAS-ENVISAT as
well as the airborne observations by the limb-sounder MIPAS-STR and the in situ particle
probe FSSP-100 (Forward Scattering Spectrometer Probe 100) aboard the high-altitude
aircraft Geophysica. The observations aboard the Geophysica on 11 December 2011
associated to ESSenCe (ESa Sounder Campaign 2011) provided us the unique opportunity to
study in detail the lower boundary region of a PSC where large potential NAT particles (>20
μm in diameter) were detected in situ. We analyse the ambient temperatures and
gas-phase composition (HNO3 and H2O), the signatures of the observed particles
in the CALIPSO and MIPAS observations, the HNO3-content of these particles
suggested by the FSSP-100 and MIPAS-STR observations, and focus on the spectral
fingerprint of these particles in the MIPAS-STR observations. While the spectral
characterisation of the observed particles is subject of ongoing work, our results support
that these particles consist of NAT and that the particle shape plays a crucial role. |
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