Fig 6 - uploaded by Nikolay Zabotin
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Two plots of north-south echo direction similar to Fig. 5, showing travelling ionospheric disturbances (TIDs) propagating southward, as witnessed by the periodic southward extending fingers of echoes. The ionospheric trough is also visible in the evening near 18 UT.
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A description, history and the capabilities of an ionospheric sounder in the auroral zone near Tromsø, Norway are presented, together with some scientific applications. The sounder, which is of the dynasonde type, has provided a data set which has improved dramatically in quantity, quality and information content. A similar sounder is planned to be...
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The first high-frequency (HF, 8 MHz) observations of the modulation of polar mesospheric summer echoes (PMSE) by artificial radio heating of the ionosphere are presented and compared to observations at 224 MHz and model predictions. The experiments were performed at the EISCAT facility in northern Norway. It is shown that model results are in quali...
The results of experimental studies of characteristics of artificial, small-scale, ionospheric irregularities in the high-latitude ionospheric F region caused by the controlled injection of high-power, high-frequency (HF) radio waves of extraordinary polarization (X mode) are presented. The experiments were carried out at the HF European Scientific...
Experimental results from multi-instrument observations at the EISCAT HF heating facility at Tromsø, Norway, are presented. We compare distinctive features of artificial plasma turbulences in the high latitude ionosphere F-region induced by powerful HF electromagnetic waves with the ordinary (O-mode) and extraordinary (X-mode) polarization.
We present experimental investigations of distinctive features and behaviors of artificial small-scale field-aligned irregularities (AFAIs) in the high latitude ionosphere F-region induced by the ordinary (O-mode) and extraordinary (X-mode) polarized HF pump waves. Results are based on a large body experiments carried out at the EISCAT HF heating f...
One of the most powerful solar proton precipitations (SPP), which began on 29 September 1989, was at the same time the longest one. This peculiarity gave to us the possibility to study on the base of VLF data the precipitation effect during a sunset on the dynamics of the electric properties of the lowest part of the ionosphere in the terms of comp...
Citations
... In addition, they do not require a dedicated mode of operation for ion drift and can be performed simultaneously with the measurements of ionospheric density profile. There have been a few Dynasonde observations of the ionosphere in the polar regions (e.g., Jarvis, 1995;Rietveld et al., 2008) and currently the JVD is the only Dynasonde observation system in the southern hemisphere including Antarctica. ...
Plain Language Summary
The ion drift velocity in the polar ionosphere is one of the key parameters for understanding not only the dynamics of the ionosphere but also the magnetosphere‐ionosphere coupling processes and the magnetospheric energy transfer to the neutral atmosphere via ion‐neutral interactions. There are several ground‐based observational techniques to monitor the ion velocities in the polar region. For example, the incoherent scatter radars (ISRs) can determine the ion motion in the polar region, but usually require expensive resources for their maintenance and operation, which makes them affordable only to large organizations or international consortiums such as EISCAT. Another widely utilized observational system for the ion velocities in the polar region is the SuperDARN radars but they are relatively scarce in Antarctica. The most affordable technique for monitoring the ionosphere is the ionospheric sounding systems capable of observing not only the ionospheric densities but also the ion velocities in the bottomside ionosphere. An advanced sounding system has been operated at Jang Bogo Station in Antarctica since 2017 to produce ionospheric parameters including ion density and velocities. The observed ion velocities are compared with simultaneously observed SuperDARN ion velocities over the JBS and we discuss similarities and differences between the two measurements.
... The effective radiated power (ERP) of the X-polarized pump wave was 290.9 MW, while the O-mode leakage had an ERP of 0.4 MW, resulting in leakage of only 0.13%. The radiation pattern of the PAA complex is automatically calculated using specialized software [16], with the input The geophysical conditions during the experiments were monitored using a magnetovariational station and a vertical ionosonde, both located in close proximity to the facility [17]. The parameters of the ionospheric plasma (electron and ion temperatures T e and T i , as well as electron density/N e ) were diagnosed using a noncoherent scatter radio wave radar spatially co-located with the heating facility [18]. ...
... Technological advances have enabled the latest generation of digital ionosondes to be developed at a high level of sensitivity and with an increased capacity for sophisticated signal and image processing (Ayliffe et al., 2019). Notable examples from the last two decades include the Digisonde DPS-4D (Reinisch et al., 2008), the Canadian Advanced Digital Ionosonde (CADI) (Morris et al., 2004), VIPIR/Dynasonde (Rietveld et al., 2008), AIS-INGV (Zuccheretti et al., 2003), IRIS (Arthur et al., 1997), Cyclone (Akchurin et al., 2009), and WMISS (Gong et al., 2016). Their implementation allowed the routine monitoring of ionospheric plasma (apparent) motion to become common practice. ...
... The data set has been chosen because it overlaps with both seismometric array operation and the hydrophone deployment period. The ionospheric sounding system at JBS utilizes the Dynasonde mode of operation and the Dynasonde analysis software to perform HF echo recognition, ionogram inversion, and to produce ionospheric characteristics such as bottom-side ionospheric electron density profiles with error bars, the F-region maximum plasma frequency (foF2) and the peak height (hmF2), estimates for the speed of ion drifts, and ionospheric tilts (Kim et al., 2022;Rietveld et al., 2008;Zabotin et al., 2006). It is also very efficient in detection and characterization of ionospheric wave activity (Zabotin et al., 2017). ...
The main subject of this study is the low‐frequency (with the periods longer than 2 hr) wave processes in the coupled regional system of the Ross Ice Shelf (RIS), the Ross Sea and the atmosphere above them. We investigate possible causal relationships between the wave activity in the three media using a unique set of geophysical instruments: a hydrophone measuring pressure variations on the seafloor, a network of seismometers measuring vertical displacements of the RIS surface, and a Dynasonde system measuring wave characteristics at the ionospheric altitudes. We present an extension of the previously introduced theoretical model of the coupled resonance vibrations of the RIS that quantifies the connection between the ocean tide and the resonance vibrations of the RIS. The ocean tide is confirmed as the most significant source of excitation of the resonances. Analysis of average power spectra in year‐long data sets reveals multiple harmonics of the tide (eight) detected by the RIS seismometers while only three are detected by the seafloor sensor. This may represent a confirmation of the effect of resonance‐related broadband amplification predicted by the model. Several peaks in the spectrum of RIS vibrations have periods different from the periods of nearby tidal constituents and may be associated with broad‐scale resonance RIS vibrations. Resonances may play a role in maintaining the coupled atmosphere‐ocean wave activity. Our results reveal a statistically significant correlation between the spectra of the vertical displacements of the RIS and the spectra of the atmospheric waves.
... A phased array with a bandwidth of 5-6° (at -3 dB level), providing the effective radiated power ERP = 360-820 MW, was utilized in the course of the experiments. The choice of the heater frequency was made in the real time from the Tromsø dynasonde [11]. ...
The paper presents experimental results concerning disturbances of electron density in the high latitude ionosphere F-region, induced by powerfulHF radio waves (pump waves) with extraordinary (X-mode) polarization. The experiments were carried out at the EISCAT/Heating facility at Tromsø, Norway. The EISCAT UHF incoherent scatter radar (ISR), running at 930 MHz, co-located with a heating facility, was used to detect the disturbances of electron density. In the course of the experiments, the X-mode HF pump waves radiated into the F-region towards the magnetic zenith at different pump frequencies and ratios of the pump frequency to the critical frequency of the F2 layer.The effective radiated power was ERP = 360–820 MW. An increase in electron densities was found in a wide altitude range, giving rise to field-aligned ducts with enhanced electron density. The features and behavior of the ducts were investigated. It was revealed that the ducts are formed under quiet background geophysical conditions in a wide altitude range up to the upper altitude limit of EISCAT ISR measurements, when the pump frequencies were both below and above the critical frequency of the F2 layer (f H ≤ f o F2 or f H > f o F2). A plausible formation mechanism of the ducts is discussed.
... In addition to the SGO ionosonde, the dynasonde located in Tromsø, with typically 6-min time resolution, is available (Rietveld et al. 2008) and revealed to be an interesting further resource to study the thermospheric gravity wave activity (Zabotin et al. 2015). ...
The Antarctic and Arctic regions are Earth's open windows to outer space. They provide unique opportunities for investigating the troposphere–thermosphere–ionosphere–plasmasphere system at high latitudes, which is not as well understood as the mid- and low-latitude regions mainly due to the paucity of experimental observations. In addition, different neutral and ionised atmospheric layers at high latitudes are much more variable compared to lower latitudes, and their variability is due to mechanisms not yet fully understood. Fortunately, in this new millennium the observing infrastructure in Antarctica and the Arctic has been growing, thus providing scientists with new opportunities to advance our knowledge on the polar atmosphere and geospace. This review shows that it is of paramount importance to perform integrated, multi-disciplinary research, making use of long-term multi-instrument observations combined with ad hoc measurement campaigns to improve our capability of investigating atmospheric dynamics in the polar regions from the troposphere up to the plasmasphere, as well as the coupling between atmospheric layers. Starting from the state of the art of understanding the polar atmosphere, our survey outlines the roadmap for enhancing scientific investigation of its physical mechanisms and dynamics through the full exploitation of the available infrastructures for radio-based environmental monitoring.
... Recently, an ionospheric sounding system was installed at Jang Bogo Station (JBS), Antarctica, and started operating in 2017 to collect ionospheric parameters in the southern polar region. The sounding system is called the Vertical Incidence Pulsed Ionospheric Radar (VIPIR), and it utilizes the Dynasonde mode of operation and the Dynasonde analysis software to conduct echo recognitions and ionogram inversions to produce ionospheric parameters such as bottomside ionospheric electron density profiles with error bars, the F-region peak density (NmF2) and the peak height (hmF2), estimates for the ion drifts, and ionospheric tilts [5][6][7][8]. The JBS-VIPIR-Dynasonde (JVD) is distinguished from a conventional digital ionosonde, for example, the digisonde series from Lowell Digisonde International, which is one of the most widely operated digital ionospheric sounding systems around the globe (e.g., see https://www.digisonde.com/index.html, ...
Vertical incidence pulsed ionospheric radar (VIPIR) has been operated to observe the polar ionosphere with Dynasonde analysis software at Jang Bogo Station (JBS), Antarctica, since 2017. The JBS-VIPIR-Dynasonde (JVD) provides ionospheric parameters such as the height profile of electron density with NmF2 and hmF2, the ion drift, and the ionospheric tilt in the bottomside ionosphere. The JBS (74.6°S, 164.2°E) is located in the polar cap, cusp, or auroral region depending on the geomagnetic activity and local time. In the present study, an initial assessment of JVD ionospheric densities is attempted by the comparison with GPS TEC measurements which are simultaneously obtained from the GPS receiver at JBS during the solar minimum period from 2017 to 2019. It is found that the JVD NmF2 and bottomside TEC (bTEC) show a generally good correlation with GPS TEC for geomagnetically quiet conditions. However, the bTEC seems to be less correlated with the GPS TEC with slightly larger spreads especially during the daytime and in summer, which seems to be associated with the characteristics of the polar ionosphere such as energetic particle precipitations and large density irregularities. It is also found that the Dynasonde analysis seems to show some limitations to handle these characteristics of the polar ionosphere and needs to be improved to produce more accurate ionospheric density profiles especially during disturbed conditions.
... The ionosonde, as the vertical sounding mode, is a widely used tool for monitoring the ionosphere and plays a significant role for studying ionosphere characteristics in the near real-time method. With the development of the modern advanced ionospheric sounders, many notable ionosondes, such as DPS-4D (Digisonde Portable Sounder) [1], Dynasonde [2], CADI (Canadian Advanced Digital Ionosonde) [3], AIS-INGV (Advanced Ionospheric Sounder-Istituto Nazionale di Geofi sica e Vulcanologia) [4], WISS (Wuhan Ionospheric Sounding System) [5], etc., have been developed to carry out the vertical sounding of the ionosphere. Subsequently, many well-established software tools, including ARTIST (Automatic Real-Time Ionogram Scaling True-height) [6], NeX-tYZ (pronounced "next wise") [7], UDIDA (Univap Digital Ionosonde Data Analysis) [8], Autoscala [9], and ionoScaler [10], have been equipped with ionosondes to automatically extract parameters and electron density profiles from vertical ionograms. ...
... where ∆ f w is the horizontal size of the searching window, ∆ f is the resolution of the frequency in oblique ionograms, P max is the maximum height of the searching window, P min is the minimum height of the searching window, and ∆P is the resolution of the group path in oblique ionograms. The present method defined ∆ f w as the width of the working frequency (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15). The values of P max and P min varies depending on the E and F layers. ...
In this study, a method is proposed to carry out automatic inversion of oblique ionograms to extract the parameters and electron density profile of the ionosphere. The proposed method adopts the quasi-parabolic segments (QPS) model to represent the ionosphere. Firstly, numerous candidate electron density profiles and corresponding vertical traces were, respectively, calculated and synthesized by adjusting the parameters of the QPS model. Then, the candidate vertical traces were transformed to oblique traces by the secant theorem and Martyn’s equivalent path theorem. On the other hand, image processing technology and characteristics of oblique echoes were adopted to automatically scale the key parameters (the maximum observable frequency and minimum group path, etc.) from oblique ionograms. The synthesized oblique traces, whose parameters were close to autoscaled parameters, were selected as the candidate traces to produce a correlation with measured oblique ionograms. Lastly, the proposed algorithm searched the best-fit synthesized oblique trace by comparing the synthesized traces with oblique ionograms. To test its feasibility, oblique ionograms were automatically scaled by the proposed method and these autoscaled parameters were compared with manual scaling results. The preliminary results show that the accuracy of autoscaled maximum observable frequency and minimum group path of the ordinary trace of the F2 layer is, respectively, about 91.98% and 86.41%, which might be accurate enough for space weather specifications. It inspires us to improve the proposed method in future studies.
... J. W. (Bill) Wright, and R. Grubb were valuable collaborators in the set-up and use of this versatile instrument. The computer hardware, operating and analysis 165 software were later upgraded such that this instrument is still providing advanced high-quality ionospheric data to this day (Rietveld et al., 2008). ...
We present the historical background to the construction of a major ionospheric heating facility near Tromsø, Norway in the 1970s by the Max Planck Institute for Aeronomy and the subsequent operational history to the present. It was built next to the EISCAT incoherent scatter radar facility and in a region with a multitude of diagnostic instruments used to study the auroral region. The facility was transferred to the EISCAT Scientific Association in January 1993 and continues to provide new discoveries in plasma physics and ionospheric and atmospheric science to this day. It is expected that ‘Heating’ will continue operating together with the new generation of incoherent scatter radar, called EISCAT_3D, when it is commissioned in the near future.
... The same year, Morris et al. (2007) reported similar semidiurnal variations of PMSE strength and OR for one season from 2004-2005 at Davis, Antarctica. Bremer et al. (2009) reported long-term observations of PMSE by ESRAD during 1999-2008, while Smirnova et al. (2010 studied the diurnal and the day-to-day variations of PMSE observed by ES-RAD during 1997-2008. Latteck and Bremer (2013 (Li HL et al., 2007a). ...
... The same year, Morris et al. (2007) reported similar semidiurnal variations of PMSE strength and OR for one season from 2004-2005 at Davis, Antarctica. Bremer et al. (2009) reported long-term observations of PMSE by ESRAD during 1999-2008, while Smirnova et al. (2010 studied the diurnal and the day-to-day variations of PMSE observed by ES-RAD during 1997-2008. Latteck and Bremer (2013 (Li HL et al., 2007a). ...
... The ionogram is shown in Figure 2. The data are commonly recorded once every quarter of an hour, with the x-axis and y-axis representing frequency (MHz) and virtual altitude (km), respectively. The main parameters of the Digisonde and EISCAT VHF radars are collected in Table 1 (Rietveld et al., 2008). The local time (LT) at Tromsø is 1 hour ahead of universal time (LT = UT+1 hr). Figure 1 shows an obvious PMSE event at an altitude of 80-90 km. ...
Polar mesosphere summer echoes (PMSE) are observed simultaneously with Digisonde and EISCAT VHF radar. The phenomenon of irregular Es layers is called PMSE-like or PMSE-Es (Polar Mesosphere Summer Echoes-Es) and has some relationship with real PMSE. In this paper, the characteristics of irregular Es layers at 80–100 km were observed by Digisonde at Tromsø during 2003–2014 are statistically analyzed with ionograms. The diurnal, day-to-day and year-to-year variations and discrepancies of occurrence rate between PMSE and PMSE-Es are compared with the statistical results observed by Esrange MST radar (ESRAD), and the reasons are discussed. The results show that the trends in the occurrence rate of PMSE-Es are similar to the trends in the occurrence rate of PMSE, but there are some notable differences. The occurrence rate of PMSE-Es is much lower than the occurrence rate of PMSE. The minimum value of PMSE-Es appears 1–2 hours earlier than the minimum value of the PMSE occurrence rate, while PMSE-Es appear earlier than PMSE in the year. In addition, there is a significant positive correlation between the annual average occurrence rates of PMSE and PMSE-Es. PMSE-Es is a relatively important occurrence in the polar mesopause. Analysis of its characteristics can provide new ideas and methods for studying the formation mechanism of PMSE.
