Effect of electrojet on the total electron content of the ionosphere over the Indian subcontinent

Deshpande, M. R.; Rastogi, R. G.; Vats, Hari Om; Klobuchar, J. A.; Sethia, G.; Jain, A. R.; Subbarao, B. S.; Patwari, V. M.; Janve, A. V.; K., R.; Singh, Mohit Kumar; Gurm, H. S.; Murthy, B. S.

doi:10.1038/267599a0

Cited by 31 publications

(25 citation statements)

References 8 publications

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“…As the strength of EEJ waxes and wanes from one day to the next, the crest latitude expands poleward or contract equatorward accordingly. A remarkable association between the strengths of EEJ and EIA was reported by several workers (Deshpande et al, 1977;Huang et al, 1989;Stolle et al, 2008). The EEJ strength may thus be considered to be a diagnostic for the EIA and hence for equatorial fountain under quiet geomagnetic condition.…”

Section: Introductionmentioning

confidence: 88%

Electrojet control of ambient ionization near the crest of the equatorial anomaly in the Indian zone

Chakraborty¹,

Hajra²

2009

Ann. Geophys.

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Abstract. A long-term (1978-1990) database of total electron content (TEC) from a location (Calcutta: 22.58 • N, 88.38 • E geographic, dip: 32 • N) near the northern crest of the equatorial ionization anomaly has extensively been studied to characterize the contribution of fountain effect in the maintenance of ambient ionization. The equatorial electrojet (EEJ) data obtained from ground magnetometer recording are used to assess the contribution of equatorial fountain. Analysis made with instantaneous values, day's maximum values and time-integrated values of EEJ strength exhibit more or less similar features. When instantaneous values of EEJ are considered TEC variations exhibit two maxima in correlation, one around 10:00-12:00 IST and the other around 18:00-20:00 IST. The later maximum in correlation coefficient is conspicuously absent when integrated values of EEJ are considered. An impulse-like feature is reflected in the diurnal TEC variation during the time intervals (09:00-10:00 IST) and (18:00-19:00 IST). The statistical analysis reveals greater correspondence with high level of significance between diurnal TEC and EEJ in the descending epoch of solar cycle than in the ascending one. On the seasonal basis, TEC in the summer solstitial months are observed to be more sensitive to the changes in EEJ strength than in the equinoctial and winter solstitial months. Combining the effects of solar flux, season, local time and EEJ an empirical formula for monthly mean diurnal TEC has been developed and validated using observed TEC data. An estimation of the relative contributions of the several terms appearing in the formula reveals much more solar flux contribution (∼50-70%) in the maintenance of ambient ionization around the present location than the EEJ effects (maximum∼20%).

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Section: Introductionmentioning

confidence: 88%

Electrojet control of ambient ionization near the crest of the equatorial anomaly in the Indian zone

Chakraborty¹,

Hajra²

2009

Ann. Geophys.

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“…The repositioning of ATS-6 at 35E, in July 1975, provided such an opportunity when well co-ordinated measurements were carried out at a number of institutions in India. The details of these stations (Table 1) and some of the preliminary results have already been reported earlier (DESHPANDE et al, 1977;SINGH et al, 1978;SETHIA et al, a, b, 1979. In addition, Nm (F2 region peak electron density) data is used from the stations, Kodaikanal, Ahmedabad and Delhi (Table 1).…”

mentioning

confidence: 84%

Equatorial electrojet control of the low latitude ionosphere.

Sethia

Rastogi

Deshpande

et al. 1980

J. geomagn. geoelec

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The role of the equatorial electrojet on the distribution of ionization at low latitudes has been discussed using mult-location Total Electron Content (TEC) data obtained through the radio beacon signals from the geostationary satellite ATS-6 and from ground-based ionosonde data. It has been found that the electrojet has a pronounced influence on TEC at latitudes extending from equator to as high as 25N dip latitude. It is suggested that ionosphere-to-plasmasphere ionization flow plays an important role in understanding the behaviour of the equatorial TEC.

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“…Pei-RenChen (1992) has con®rmed this relationship using numerical simulation. ) and DH (nano Tesla, nT) but not in F 10.7 (10 )22 Watts/ square meter/cycle per second bandwidth) and A p Deshpande et al (1977), Sethia et al (1980) and Lakshmi et al (1985) showed that there exists a close correlation between the development of equatorial anomaly in IEC max and the electrojet strength at the crest location whereas there exists no such correlation at the equator. Dabas et al (1984) studied the day-to-day changes in IEC max using multi-station data covering the 15°N±30°N latitude range in the Indian zone during solar minimum.…”

Section: Alternate Day Abnormalitymentioning

confidence: 99%

Long term ionospheric electron content variations over Delhi

Gupta

Singh

2001

Annales Geophysicae

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Abstract. Ionospheric electron content (IEC) observed at Delhi (geographic co-ordinates: 28.63°N, 77.22°E; geomagnetic co-ordinates: 19.08°N, 148.91°E; dip Latitude 24.8°N), India, for the period 1975±80 and 1986± 89 belonging to an ascending phase of solar activity during ®rst halves of solar cycles 21 and 22 respectively have been used to study the diurnal, seasonal, solar and magnetic activity variations. The diurnal variation of seasonal mean of IEC on quiet days shows a secondary peak comparable to the daytime peak in equinox and winter in high solar activity. IEC max (daytime maximum value of IEC, one per day) shows winter anomaly only during high solar activity at Delhi. Further, IEC max shows positive correlation with F 10.7 up to about 200 ux units at equinox and 240 units both in winter and summer; for greater F 10.7 values, IEC max is substantially constant in all the seasons. IEC max and magnetic activity (A p ) are found to be positively correlated in summer in high solar activity. Winter IEC max shows positive correlation with A p in low solar activity and negative correlation in high solar activity in both the solar cycles. In equinox IEC max is independent of A p in both solar cycles in low solar activity. A study of day-to-day variations in IEC max shows single day and alternate day abnormalities, semi-annual and annual variations controlled by the equatorial electrojet strength, and 27-day periodicity attributable to the solar rotation.

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Effect of electrojet on the total electron content of the ionosphere over the Indian subcontinent

Cited by 31 publications

References 8 publications

Electrojet control of ambient ionization near the crest of the equatorial anomaly in the Indian zone

Electrojet control of ambient ionization near the crest of the equatorial anomaly in the Indian zone

Equatorial electrojet control of the low latitude ionosphere.

Long term ionospheric electron content variations over Delhi

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