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Indian Journal of Radio & Space Physics (IJRSP) >
IJRSP Vol.39 [2010] >
IJRSP Vol.39(6) [December 2010] >
| Title: | Abnormally low F-layer ionization over Ahmedabad during the night of 26-27 November 1984 |
| Authors: | Chandra, H
Vyas, G D |
| Keywords: | F-layer ionization
F-layer critical frequency
Ionospheric abnormality
Electron density |
| Issue Date: | Dec-2010 |
| Publisher: | NISCAIR-CSIR, India |
| PACS No.: | 94.20.Vv; 94.20.dj |
| Abstract: | A case study of the critical frequency of F2
layer (foF2) over Ahmedabad (Geog latitude 23°N, longitude 72.4°E) during 17-30
November 1984, a
geomagnetic quiet period, has been carried out. An interesting
feature observed is very low values of foF2 (2.3 MHz) around 2100 hrs LT on 26
November. The quarter hourly ionograms during the night of 26-27 November 1984
were subjected to true height analysis to study the features of F-layer. The
variations of hm show rapid rise of about 100 km at 2100 hrs LT
followed by rapid fall of similar magnitude at 0100 hrs LT. The quasi-periodic
variations with periods of about 90 min are also seen. The variation of the
semi-thickness of F-layer also shows similar wave-like features. The wave-like
perturbations of about 12 km
in F-layer height and about 16
km in the semi-thickness of F-layer point to gravity
waves in neutral winds and temperature as their source. |
| Page(s): | 346-352 |
| CC License: |  CC Attribution-Noncommercial-No Derivative Works 2.5 India |
| ISSN: | 0975-105X (Online); 0367-8393 (Print) |
| Source: | IJRSP Vol.39(6) [December 2010]
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