Abstract
VHF amplitude scintillations recorded during the daytime period from January 1991 to December 1993, April 1998 to December 1999 and January 2008 to December 2008 at low latitude station Varanasi (geographic lat. = 25°15′N; long. = 82°59′E; geomagnetic lat. = 14°55′N, long. = 154°E, dip angle = 37.3°, sub-ionospheric dip = 34°) have been analyzed to study the behaviour of ionospheric E-region irregularities during the active solar and magnetic periods. The autocorrelation functions, power spectral densities, signal de-correlation times are computed to study the temporal features of ionospheric E-region irregularities linked with daytime scintillations. Derived spectral index ranges between −2 and −9. Assuming velocity of irregularities, the characteristic lengths of the E-region irregularities are estimated. We have estimated the minimum and maximum range of scale length of sporadic-E (E s ) irregularities to be observed over Varanasi. These results are in close agreement with those reported from this latitude region.
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References
Aarons J, Mullen P and Basu S 1963 Geomagnetic control of satellite scintillations; J. Geophys. Res. 68 33,159.
Aarons J and Whitney H E 1968 Ionospheric scintillation at 136 MHz from a synchronous satellite; Planet. Space Sci. 16 21–28.
Anastassiadis M, Matsoukas D and Moraitis G 1970 40-MHz ionospheric scintillation and the sporadic-E layer; Radio Sci. 5 953–957.
Basu S, Aarons J, Balsley and Ben B 1977 On the nature of electrojet irregularities responsible for the daytime VHF scintillations; J. Geophys. Res. 82 5262–5266.
Basu S and Basu Su 1989 Scintillation technique for probing ionospheric irregularities in World Ionospheric/Thermospheric studies (WITS) Handbook (ed.) Liu C H, SCOSTEP University of Ill., Urbana, 2 128–130.
Bourdillon A, Lefur E, Haldoupis C, Roux Y Le, Menard J and Delloue J 1997 Decameter mid-latitude sporadic-E irregularities in relation with gravity waves; Ann. Geophys. 15 925–934.
Chandra H and Rastogi R G 1975 Blanketing sporadic E layer near the magnetic equator; Geophys. Res. 80 149–153.
Chandra H, Vyas G D, Rao D R K, Pathan B M, Iype A, Ram Sekran B, Tyagi T R, Vijaykumar P N, Singh L, Iyer K N, Pathak K N, Gwal A K, Sushil K, Singh R P, Singh U P, Singh B, Jain V K, Navaneeth G N, Koparkar P V, Rama Rao P V S, Jayachandran P T, Sriram P, Santa Rao N Y S, Das Gupta, A, Basu K and Rastogi R G 1993 Coordinated multi-station VHF scintillation observations in India during March–April 1991; Ind. J. Radio & Space Phys. 22 69.
Chavdarov S S, Chernysheva S P and Shatkhin Kh Z 1966 Stability of reflection from sporadic-E layers and solar activity; Geomagn. Aeron. 6 109.
Crane R K 1976 Spectra of ionospheric scintillation; J. Geophys. Res. 81 2041–2050.
Crane R K 1977 Ionospheric scintillation; Proc. IEEE 65 180–199.
DasGupta A and Kersley L 1976 Summer daytime scintillations and sporadic-E; J. Atmos. Terr. Phys. 38 615–618.
Franke S J and Liu C H 1983 Observations and modeling of multi-frequency VHF and GHz scintillations in the equatorial region; J. Geophys. Res. 88 7075–7085.
Fujita M, Sinno K and Ogawa T 1982 Frequency dependence of ionospheric scintillations and its application to spectral estimation of electron density irregularities; J. Atmos. Terr. Phys. 44 13–18.
Goodman J 1967 Some evidence of E s-layer effects upon 136 MHz radio waves; J. Atmos. Terr. Phys. 29 607–612.
Hajkowicz L A and Dearden D J 1988 Observations of random and quasi-periodic scintillations at southern mid-latitudes over a solar cycle; J. Atmos. Terr. Phys. 50 511–517.
Hajkowicz L A and Minakoshi H 2003 Mid-latitude ionospheric scintillation anomaly in the Far East; Ann. Geophys. 21 577–581.
Jahn J M and LaBelle J 1998 Rocket measurements of high-altitude spread-F irregularities at the magnetic dip equator; J. Geophys. Res. 103(A10) 23,427–23,441.
Khastgir S R and Singh R N 1960 The size of moving irregularities in the F-region and spread angle of the radio waves scattered from them; J. Atmos. Terr. Phys. 18 123–126.
Kumar S, Gwal A K, Rama Rao P V S, Jayachandran P T, Prasad S V V D, Singh R P, Singh U P, Dasgupta A, Basu K, Sethuraman ai]R, Pathan B M, Rao D R K, Banola S, Kesava Rao P S, Naidu A, Tyagi T R, Vijaykumar P N, Chandra H, Vyas G D, Singh B, Chauhan P, Iyer K N, Pathak K N, Shalgaonkar C S, Vyas B M and Rastogi R G 2000 Co-ordinated observations of VHF scintillations in India during February–March 1993; Ind. J. Radio Space Phys. 29 22.
Ogawa T, Suzuki A and Kunitake M 1989 Spatial distribution of mid-latitude sporadic-E scintillations in summer daytime; Radio Sci. 24 527–538.
Patel K, Singh A K, Patel R P and Singh R P 2007 Ionospheric scintillations by sporadic-E irregularities over low latitude; Bull. Astr. Soc. India 35 625–630.
Patel K, Singh A K and Singh R P 2009 Observations and modeling of quasi-periodic scintillations observed at low latitude; J. Phys. C. S. (in press).
Rastogi R G and Iyer K N 1976 Ionospheric scintillations induced by cloud of intense sporadic-E layer; Curr. Sci. 45 685–686.
Rastogi R G, Deshpande M R, Murthy B S and Davies K 1977 Daytime satellite radio scintillations and sporadic-E near the magnetic equator; Geophys. Res. Lett. 4 113.
Rastogi R G 1980 Daytime radio wave scintillations in the equatorial electrojet regions; Ind. J. Radio Space Phys. 9 219.
Singleton D and Lynch G 1962 The scintillation of the radio transmissions from Explorer VII-I; J. Atmos. Terr. Phys. 24 353–360.
Singh A K 1993 Study of VLF whistlers and VHF scintillations, Ph.D. Thesis, Banaras Hindu University, Varanasi.
Singh A K and Singh R P 1997 Observations and modelling of nocturnal ionospheric irregularities in low latitude region; J. Geomag. Geoelectr. 49 1115–1129.
Singh R P, Patel R P and Singh A K 2004 Effect of solar and magnetic activity on VHF scintillations near the equatorial anomaly crest; Ann. Geophys. 22 2849–2860.
Singh A K, Patel R P and Singh R P 2006 Statistical features of overhead ionospheric irregularities and its generation mechanism at low latitude; J. Atmos. Solar Terr. Phys. 68 1116–1124.
Somayajulu Y V, Garg S C and Vijay Kumar P N 1977 Scintillation Studies using ATS-6 Radio Beacons at Delhi; Indian J. Radio Space Phys. 6 250–256.
Tsunda R T, Fukao S and Yamamoto M 1994 On the origin of quasi-periodic radar backscatter from mid-latitude sporadic-E; Radio Sci. 29 349–365.
Vijayakumar P N, Tyagi T R, Singh L, Chandra H, Vyas G D, Rao D R K, Pathan B M, Iype A, Ramsekaran B, Naidu A, Sadique S M, Iyer K N, Pathak K N, Gwal A K, Kumar S, Singh R P, Singh U P, Singh B, Kumar P, Navneeth G N, Koparkar P V S, Ramarao P V S, Jaychandran P T, Sriram P, Sethuraman R, Dasgupta A, Basu K and Rastogi R G 2007 Some features of plasma bubble induced scintillations during the AICPITS campaigns of 1991; Ind. J. Radio Space Phys. 36 91–102.
Whitney H E, Aarons J and Malik C A 1969 Proposed index for measuring ionospheric scintillation; Planet. Space Sci. 17 1069–1073.
Woodman R F, Yamamoto M and Fukao S 1991 Gravity wave modulation of gradient drift instabilities in mid-latitude sporadic-E; Geophys. Res. Lett. 18 1197–1200.
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Patel, K., Singh, A.K., Patel, R.P. et al. Characteristics of low latitude ionospheric E-region irregularities linked with daytime VHF scintillations measured from Varanasi. J Earth Syst Sci 118, 721–732 (2009). https://doi.org/10.1007/s12040-009-0058-x
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DOI: https://doi.org/10.1007/s12040-009-0058-x