Please use this identifier to cite or link to this item: http://nopr.niscair.res.in/handle/123456789/35785
Title: Diurnal variation in diffusion coefficient and occurrence rate of radio meteor trails
Authors: Reddi, C Raghava
Rajeev, K
Ramkumar, Geetha
Issue Date: Apr-1995
Publisher: NISCAIR-CSIR, India
Abstract: The daily variation in the occurrence rate (per hour) of radio meteors observed by the 54.95 MHz radar operated at Trivandrum (8.5°N, 77°E) during each month of the year is discussed. From the exponential amplitude decay rate of 62,081 carefully selected underdense meteor trails, the ambipolar diffusion coefficients (D) in the 80-105 km altitude region of the atmosphere have been determined. The D values have been used to study the diurnal (d), semi-diurnal (sd) and ter-diurnal (td) variations of the hourly mean diffusion coefficient of the atmosphere which corresponds to an altitude close to 92 km. These diurnal and its sub-harmonic variations have been interpreted in terms of the temperature oscillations of the mesopause region. It is found that the annual mean d oscillation of the mesopause temperature is of amplitude 21.8 K while sd and td oscillation amplitudes are both equal to 3.5 K. These results have been compared with the results from theoretical models and the scantly available observations using rockets. It is significant to note that td mesopause temperature oscillation is as significant as sd oscillation.
Page(s): 55-63
URI: http://nopr.niscair.res.in/handle/123456789/35785
ISSN: 0975-105X (Online); 0367-8393 (Print)
Appears in Collections:IJRSP Vol.24(2) [April 1995]

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