A comparison of two different techniques for deriving the quiet day curve from SARINET riometer data

Moro, Juliano; Denardini, Clezio Marcos; Correia, E.; Abdu, M. A.; Schuch, Nelson Jorge; Makita, Kazuo

doi:10.5194/angeo-30-1159-2012

Cited by 10 publications

(7 citation statements)

References 19 publications

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“…Then this method was applied by Krishnaswamy et al [16] to estimate QDC with computers. Recent work on the QDC estimate techniques refers to Tanaka et al [17] and Moro et al [20]. The former uses a percentual criterion from the cosmic noise intensity distribution to generate QDC; and the latter introduces two more criteria for data selecting process to improve QDC estimate technique.…”

Section: Methods For Qdc Estimatementioning

confidence: 99%

A new technique for deriving the quiet day curve from imaging riometer data at Zhongshan Station, Antarctic

et al. 2014

Sci. China Technol. Sci.

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A new technique for estimating quiet day curve (QDC) was suggested. To validate the new approach, QDCs were derived from data acquired by the imaging riometer installed at the Chinese Zhongshan Station in Antarctic. The evaluation was performed by comparing the difference between QDC derived by the new technique and those derived by Tanaka's technique. The results were discussed in terms of the diurnal variation and discrepancy. Also, cosmic noise absorption (CNA) images were built using both techniques in order to evaluate the implications of the changes when obtaining them using different methods of the QDC determination. The influence of the multiplicative factor value on the QDC determination in Tanaka's technique was evaluated. riometer, absorption, techniqueCitation: He F, Hu H Q, Hu Z J, et al. A new technique for deriving the quiet day curve from imaging riometer data at Zhongshan Station

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Section: Methods For Qdc Estimatementioning

confidence: 99%

A new technique for deriving the quiet day curve from imaging riometer data at Zhongshan Station, Antarctic

et al. 2014

Sci. China Technol. Sci.

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“…If we only investigate the relative changes and not the absolute values, it seems that the attenuation of Doppler signal returns to pre-flare values faster than the attenuation obtained by riometer. To investigate if there is no systematic trend in riometer attenuation during the displayed time interval, the quiet day curve (QDC) (Nishino et al 2002;Moro et al 2012) was computed as the median of daily curves obtained for 29-day interval centered at 7 August 2016 and subtracted from the measurement on 7 August 2016. The resulting curve (difference between current attenuation and QDC) is displayed Fig.…”

Section: M13 and C85 Events On 7 August 2016 Observation In Tucumámentioning

confidence: 99%

Continuous Doppler sounding of the ionosphere during solar flares

Chum

Urbář

Laštovička

et al. 2018

Earth Planets Space

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Solar flares cause a rapid increase in ionization in the ionosphere owing to significant enhancement of ionizing solar radiation in the X-ray and extreme ultraviolet (EUV) spectral ranges. The change of electron densities in the ionosphere influences the propagation of radio waves. The ionospheric response to solar flares is investigated for three selected examples recorded during the maximum and decreasing phase of the solar cycle 24 with time resolution of several seconds by continuous Doppler sounding systems installed in the Czech Republic (50N, 14E), Taiwan (24N, 121E) and Northern Argentina (27S, 65W). The reflection heights of sounding signals are derived from nearby ionospheric sounders. The measured Doppler shifts are compared with EUV and X-ray data from the GOES-15 satellite. It is shown that the largest Doppler shifts are observed at times when the time derivatives of EUV fluxes are maximal, while the Doppler shifts are around zero at times when the EUV fluxes reach maxima. This means that loss processes balance the ionization when the EUV fluxes maximize. The attenuation of Doppler signal caused by enhanced electron density in the D and E layer was well correlated with the cosmic noise absorption measured by riometer. For large ionizing fluxes, the attenuation leads to very low signal-to-noise ratio, loss of the received signal, and inability to process both Doppler shift spectrograms and ionograms.

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“…The method of determining QDC of cosmic noise signal has been discussed extensively by several authors (e.g., Mitra and Shain 1953;Lusignan 1960;Steiger and Warmick 1961;Armstrong et al 1977;Krishnaswamy et al 1985;Tanaka et al 2007). Recently, Moro et al (2012) have presented new modified technique for Riometer Network (SARINET) data from South America with respect to method of Tanaka et al (2007). In that paper, two criteria have been followed: (1) riometer data selection according to the geomagnetic activity and (2) data cleaning with respect to electromagnetic interference as well as some other noises.…”

Section: Technique For Deriving Qdcmentioning

confidence: 99%

“…In the current approach for deriving QDC of cosmic noise signal, we have used two criteria as followed by Moro et al (2012). For fulfillment of the first criterion, the average of imaging riometer data for the five international quietest days was used to derive QDC for a particular month.…”

Section: Technique For Deriving Qdcmentioning

confidence: 99%

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First results from imaging riometer installed at Indian Antarctic station Maitri

et al. 2014

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Cosmic noise absorption (CNA) measurred by imaging riometer, is an excellent tool to passively study the high latitude D-region ionospheric conditions and dynamics. An imaging riometer has been installed at Indian Antarctic station Maitri (geographic 70.75 • S, 11.75 • E; corrected geomagnetic 63.11 • S, 53.59 • E) in February 2010. This is the first paper using the imaging riometer data from Maitri. The present paper introduces the details of this facility, including its instrumentation, related CNA theory and its applications. Sidereal shift of around 2 hours in the diurnal pattern validates the data obtained from the newly installed instrument. Moreover, the strength of cosmic noise signal on quiet days also varies with months. This is apparently due to solar ionization of D-region ionosphere causing enhanced electron density where collision frequency is already high. The main objective of installing the imaging riometer at Maitri is to study magneotspheric-ionospheric coupling during substorm processes. In the current study, we present two typical examples of disturbed time CNA associated with storm-time and non-storm time substorm. Results reveal that CNA is more pronounced during storm-time substorm as compared to nonstorm-time substorm. The level of CNA strongly depends upon the strengthening of convectional electric field and the duration of southward turning of interplanetary magnetic field before the substorm onset.

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A comparison of two different techniques for deriving the quiet day curve from SARINET riometer data

Cited by 10 publications

References 19 publications

A new technique for deriving the quiet day curve from imaging riometer data at Zhongshan Station, Antarctic

A new technique for deriving the quiet day curve from imaging riometer data at Zhongshan Station, Antarctic

Continuous Doppler sounding of the ionosphere during solar flares

First results from imaging riometer installed at Indian Antarctic station Maitri

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