 |
| Titel |
Aspect sensitivity in the VHF radar backscatters studied using simultaneous observations of Gadanki MST radar and GPS sonde |
| VerfasserIn |
A. K. Ghosh, S. S. Das, A. K. Patra, D. N. Rao, A. R. Jain |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
0992-7689
|
| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 22, no. 11 ; Nr. 22, no. 11 (2004-11-29), S.4013-4023 |
| Datensatznummer |
250015068
|
| Publikation (Nr.) |
 copernicus.org/angeo-22-4013-2004.pdf |
|
|
|
|
|
| Zusammenfassung |
| Simultaneous observations made on four days using the MST radar and
GPS-sonde at Gadanki (13.5° N, 79.2° E), a tropical station
in India, are presented to address the aspect sensitivity of radar
backscatters observed at different heights. The observations show that
wherever stability parameter N2 is high, vertical shear of horizontal
wind is low and Richardson number (Ri) is high, the aspect sensitivity is
high indicating that the aspect sensitive radar backscatters are due to
thermal structures in the atmosphere. Such a case can be seen very clearly in
the upper troposphere and lower stratosphere. At some heights, where N2
is high, Ri is high, but shears are relatively weak, the aspect
sensitivity is found to almost disappear, indicating that some amount of shear
provides favorable conditions for causing aspect sensitivity. Aspect
sensitivity does not occur at all where N2 is low or negative and Ri
is low in spite of wind shear being either high or low, indicating that the
regions are well mixed and hence turbulent. The study also shows a power
difference in the symmetric beams. A case study on this aspect suggests that
this asymmetry is due to the tilting of layers by the action of atmospheric
waves. There is indication that these waves are generated through
Kelvin-Helmholtz-instability (KHI). |
| |
|
| Teil von |
|
|
|
|
|
|
|
|