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| Titel |
Typhoon 9707 observations with the MU radar and L-band boundary layer radar |
| VerfasserIn |
M. Teshiba, H. Hashiguchi, S. Fukao, Y. Shibagaki |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 19, no. 8 ; Nr. 19, no. 8, S.925-931 |
| Datensatznummer |
250014303
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| Publikation (Nr.) |
 copernicus.org/angeo-19-925-2001.pdf |
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| Zusammenfassung |
Typhoon 9707 (Opal) was
observed with the VHF-band Middle and Upper atmosphere (MU) radar, an L-band
boundary layer radar (BLR), and a vertical-pointing C-band meteorological radar
at the Shigaraki MU Observatory in Shiga prefecture, Japan on 20 June 1997. The
typhoon center passed about 80 km southeast from the radar site. Mesoscale
precipitating clouds developed due to warm-moist airmass transport from the
typhoon, and passed over the MU radar site with easterly or southeasterly
winds. We primarily present the wind behaviour including the vertical component
which a conventional meteorological Doppler radar cannot directly observe, and
discuss the relationship between the wind behaviour of the typhoon and the
precipitating system. To investigate the dynamic structure of the typhoon, the
observed wind was divided into radial and tangential wind components under the
assumption that the typhoon had an axi-symmetric structure. Altitude range of
outflow ascended from 1–3 km to 2–10 km with increasing distance (within 80–260
km range) from the typhoon center, and in-flow was observed above and below the
outflow. Outflow and inflow were associated with updraft and downdraft,
respectively. In the tangential wind, the maximum speed of counterclockwise
winds was confirmed at 1–2 km altitudes. Based on the vertical velocity and
the reflectivity obtained with the MU radar and the C-band meteorological
radar, respectively, precipitating clouds, accompanied by the wind behaviour of
the typhoon, were classified into stratiform and convective precipitating
clouds. In the stratiform precipitating clouds, a vertical shear of radial wind
and the maximum speed of counterclockwise wind were observed. There was a
strong reflectivity layer called a ‘bright band’ around the 4.2 km
altitude. We confirmed strong updrafts and down-drafts below and above it,
respectively, and the existence of a relatively dry layer around the bright
band level from radiosonde soundings. In the convective precipitating clouds,
the regions of strong and weak reflectivities were well associated with those
of updraft and downdraft, respectively.
Key words. Meteorology and
atmospheric dynamics (mesoscale meteorology; precipitation) Radio science
(remote sensing) |
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