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| Titel |
Simulation study for ground-based Ku-band microwave observations of ozone and hydroxyl in the polar middle atmosphere |
| VerfasserIn |
David Newnham, Mark Clilverd, Michael Kosch, Pekka Verronen |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250141201
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| Publikation (Nr.) |
 EGU/EGU2017-4680.pdf |
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| Zusammenfassung |
| Commercial satellite TV broadcasting is possible due to remarkable advances in
microwave electronics, enabling weak signals transmitted over 36,000 km from
geostationary orbit to be received by inexpensive rooftop dishes. The Ku band satellite
frequencies (10.70–14.25 GHz) overlap microwave emissions from ozone (O3) at
11.072 GHz and hydroxyl radical (OH) at 13.44 GHz. These important chemical species
in the polar middle atmosphere respond strongly to solar variability and, at high
latitudes, geomagnetic activity associated with space weather. Atmospheric model
calculations predict that energetic electron precipitation (EEP) driven by magnetospheric
substorms produces large changes in polar mesospheric O3 and OH. The EEP typically
peaks at geomagnetic latitudes ∼65˚ (e.g. Kilpisjärvi, Finland and Syowa station,
Antarctica) and evolves rapidly with time eastwards and over the geomagnetic latitude
range 60˚ –80˚ (e.g. reaching Halley, Antarctica). During the substorms OH can
increase by more than 1000% at 64–84 km. The substorms leave footprints of
5–55% O3 loss lasting many hours of local time, with strong altitude and seasonal
dependences. An atmospheric simulation and retrieval study is performed to determine the
specification and design requirements for microwave radiometers capable of measuring O3
and OH profiles from Arctic and Antarctic locations using accessible satellite TV
receiver technology. The proposed observations are highly applicable to studies of
EEP, atmospheric dynamics, planetaryscale circulation, chemical transport, and the
representation of these processes in polar and global climate models. They would
provide a lowcost, reliable alternative to increasingly sparse satellite measurements,
extending long-term data records and also providing “ground truth” calibration data. |
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