Study of GPS ionospheric scintillations over equatorial anomaly station Bhopal during low solar activity period

2012 ◽  
Author(s):  
Shweta Mukherjee ◽  
Shivalika Sarkar ◽  
P.K. Purohit ◽  
A.K. Gwal
Keyword(s):  
Solar Activity ◽  
Activity Period ◽  
Equatorial Anomaly ◽  
Ionospheric Scintillations ◽  
Solar Activity Period

scholarly journals Daytime descending intermediate layers observed over a sub-tropical Indian station Waltair during low-solar activity period

2010 ◽  
Vol 28 (3) ◽  
pp. 807-815 ◽  
Author(s):  
K. Niranjan ◽  
B. Srivani ◽  
V. V. S. Naidu
Keyword(s):  
Solar Activity ◽  
Activity Period ◽  
Complex Nature ◽  
Equatorial Anomaly ◽  
Double Peak ◽  
Winter Solstice ◽  
Intermediate Layers ◽  
Indian Station ◽  
Solar Activity Period ◽  
Maximum Occurrence

Abstract. Study on daytime descending intermediate layer over subtropical Indian station Waltair (17.7° N, 83.3° E geographic, 6.4° N, 10° E geomagnetic, 20° N dip) located in the equatorial anomaly transition region, using an IPS 42 Digital Ionosonde during the low solar activity year 2004 showed that the layers occur in the altitude range of 140–160 km with maximum occurrence during winter solstice. The layers observed during daytime occur with a double peak variation throughout the year with less occurrence probability and shorter duration presence during forenoon hours. The morning layer descent was associated with a density increase where as during afternoon hours a decrease in density was observed. The downward drift velocity was about 8 km/h during morning hours and between 7–11 km/h during afternoon hours, with a low descent rate of around 4.5 km/h during summer morning hours. The results indicate the presence of a 6 h tide at this location as observed from the characteristics of the descending layers, unlike at majority of locations where a significant semi diurnal trend is observed. The study brings out the complex nature of the tidal interaction at different locations.

Day-to-day variability of equatorial anomaly in GPS-TEC during low solar activity period

2012 ◽  
Vol 49 (12) ◽  
pp. 1709-1720 ◽  
Author(s):  
Malini Aggarwal ◽  
H.P. Joshi ◽  
K.N. Iyer ◽  
Y.-S. Kwak ◽  
J.J. Lee ◽  
...  
Keyword(s):  
Solar Activity ◽  
Activity Period ◽  
Equatorial Anomaly ◽  
Gps Tec ◽  
Solar Activity Period

scholarly journals TEC variations during low solar activity period (2005–2007) near the Equatorial Ionospheric Anomaly Crest region in India

2009 ◽  
Vol 27 (3) ◽  
pp. 1047-1057 ◽  
Author(s):  
Mala S. Bagiya ◽  
H. P. Joshi ◽  
K. N. Iyer ◽  
M. Aggarwal ◽  
S. Ravindran ◽  
...  
Keyword(s):  
Solar Activity ◽  
Geomagnetic Storm ◽  
Activity Period ◽  
Electron Content ◽  
Ionospheric Storm ◽  
Equatorial Anomaly ◽  
Total Electron ◽  
Short Period ◽  
Storm Effect ◽  
Solar Activity Period

Abstract. The dual frequency signals from the GPS satellites recorded at Rajkot (22.29° N, 70.74° E, Geographic, 14.03° N Geomagnetic) near the Equatorial ionization anomaly crest in India have been analyzed to study the ionospheric variations in terms of Total Electron Content (TEC) for the low solar activity period from April 2005 to December 2007. In this study, we describe the diurnal and seasonal variations of TEC, solar activity dependence of TEC and effects of a space weather related event, a geomagnetic storm on TEC. The diurnal variation of TEC shows pre-dawn minimum for a short period of time, followed by a steep early morning increase and then reaches maximum value between 14:00 LT and 16:00 LT. The mean diurnal variations during different seasons are brought out. It is found that TEC at Rajkot is at its maximum during Equinoctial months (March, April, September, October), and minimum during the Winter months (November, December, January, February), with intermediate values during Summer months (May, June, July, August), showing a semi annual variation. TEC values have been decreasing since 2005, onwards showing positive correlation with solar activity. TEC variations during the geomagnetic storm commencing 24 August 2005 with Dst=−216 nT are analysed. TEC shows a positive ionospheric storm effect on the first day of the storm and negative ionospheric storm effect on the next day. The equatorial Electrojet control on the development of the equatorial anomaly is also demonstrated.

scholarly journals Post midnight spread-F occurrence over Waltair (17.7° N, 83.3° E) during low and ascending phases of solar activity

2003 ◽  
Vol 21 (3) ◽  
pp. 745-750 ◽  
Author(s):  
K. Niranjan ◽  
P. S. Brahmanandam ◽  
P. Ramakrishna Rao ◽  
G. Uma ◽  
D. S. V. V. D. Prasad ◽  
...  
Keyword(s):  
Solar Activity ◽  
Atmospheric Composition ◽  
Activity Period ◽  
Sunspot Activity ◽  
Low Latitude ◽  
F Region ◽  
Composition And Structure ◽  
Spread F ◽  
Solar Activity Period ◽  
Night Airglow

Abstract. A study carried out on the occurrence of post midnight spread-F events at a low-latitude station, Waltair (17.7° N, 83.3° E), India revealed that its occurrence is maximum in the summer solstice months of the low solar activity period and decreases with an increase in the sunspot activity. The F-region virtual height variations show that 80% of these spread-F cases are associated with an increase in the F-region altitude. It is suggested with the support of the night airglow 6300 A zenith intensity data obtained with co-located ground-based night airglow photometer and electron temperature data from the Indian SROSS C2 satellite that the seasonal variation of the occurrence and probable onset times of the post midnight spread-F depend on the characteristics of the highly variable semipermanent equatorial Midnight Temperature Maximum (MTM).Key words. Ionosphere (ionospheric irregularities; ionosphere atmosphere interactions) Atmospheric composition and structure (airglow and Aurora)

scholarly journals Comparison of IRI-2016 model with IGS VTEC maps during low and high solar activity period

2019 ◽  
Vol 12 ◽  
pp. 555-561 ◽  
Author(s):  
Chuang Shi ◽  
Tao Zhang ◽  
Cheng Wang ◽  
Zhipeng Wang ◽  
Lei Fan
Keyword(s):  
Solar Activity ◽  
Activity Period ◽  
High Solar Activity ◽  
Solar Activity Period

scholarly journals Ionospheric Peak Parameters Retrieved from FY-3C Radio Occultation: A Statistical Comparison with Measurements from COSMIC RO and Digisondes Over the Globe

2019 ◽  
Vol 11 (12) ◽  
pp. 1419
Author(s):  
Han Wang ◽  
Jia Luo ◽  
Xiaohua Xu
Keyword(s):  
Solar Activity ◽  
Correlation Coefficient ◽  
Radio Occultation ◽  
Elevation Angle ◽  
Activity Period ◽  
Time Interval ◽  
Comparison Results ◽  
Standard Deviations ◽  
The Difference ◽  
Solar Activity Period

In this study, two ionospheric peak parameters (ICPs), NmF2 and hmF2, derived from the global navigation satellite system (GNSS) radio occultation (RO) ionospheric electron density profiles (EDPs) obtained by Feng-Yun 3C (FY-3C) mission are compared with those derived from the observations of the Constellation Observing System for the Meteorology, Ionosphere, and Climate (COSMIC) mission and the measurements from 24 digisonde stations distributed around the world during the year from 2014 to 2017. The FY-3C derived ICPs and the COSMIC-derived ICPs are provided by the National Satellite Meteorological Centre (NSMC) and the COSMIC Data Analysis and Archive Center (CDAAC), respectively. The correlation and bias analyses are carried out in the comparison under the collocation criterion with the time interval of 1 h and the space interval of 3° in latitude and 5° in longitude. When comparing the ICPs derived from the two RO missions, the difference in the azimuth of occultation planes (DAOPs) between the matched pairs is limited to be within 20°. The comparison results are analyzed for different solar activity periods, and solar elevation angle (SEA) is taken for the first time as a factor that represents the comprehensive impacts of latitude zones, seasons, and local time of the observations. The results are shown as follows: (1) Both the COSMIC RO-derived and the digisonde-observed ICPs are in good agreement with the FY-3C RO-derived ones. The correlation coefficient (CC) between the NmF2 and hmF2 derived by COSMIC RO and FY-3C RO is 0.965 and 0.916, respectively, while the correlation coefficient between the NmF2 and hmF2 derived by digisonde and FY-3C RO is 0.924 and 0.832, respectively. The quality of FY-3C RO-derived ICPs are reliable enough for further applications. (2) The CC of NmF2 is, in general, higher than that of hmF2 when comparing FY-3C RO with other observations, and the overall MAB and MRB of FY-3C RO-derived ICPs during the higher solar activity period are higher than the ones during the lower solar activity period. The difference between the two RO missions is much smaller than that one between FY-3C RO and digisonde. (3) For a certain solar activity period, the standard deviations of the absolute bias (SDAB) and the standard deviations of the relative bias (SDRB) of FY-3C RO-derived ICPs compared with digisonde-derived ones generally increases with the increase of SEA, while the SDAB and SDRB of FY-3C RO-derived ICPs both get the minimum values for the AOP interval near to 90°.

scholarly journals The persistence of the NWA effect during the low solar activity period 2007-2009

2015 ◽  
Vol 120 (10) ◽  
pp. 9148-9160 ◽  
Author(s):  
N. Jakowski ◽  
M. M. Hoque ◽  
M. Kriegel ◽  
V. Patidar
Keyword(s):  
Solar Activity ◽  
Activity Period ◽  
Solar Activity Period
Sign in / Sign up

Export Citation Format

Share Document