Ionosonde and satellite data analysis in relation to the M5.9 April 6, 2009 L’Aquila (Italy) earthquake

2021 ◽  
Author(s):  
Dario Sabbagh ◽  
Loredana Perrone ◽  
Angelo De Santis ◽  
Saioa A. Campuzano ◽  
Gianfranco Cianchini ◽  
...  
Keyword(s):  
Critical Frequency ◽  
Epicentral Distance ◽  
Earthquake Magnitude ◽  
Ionospheric Disturbances ◽  
Champ Satellite ◽  
The Past ◽  
Use Of Data ◽  
Empirical Relations ◽  
Preparation Phase ◽  
Anticipation Time

<p>A combined ground-satellite study of the ionospheric response to the preparation phase of the M5.9 crustal earthquake occurred in L’Aquila (Italy) on April 6, 2009 is here presented. Ionospheric anomalies based on ionosonde observations of the altitude and blanketing frequency of the E-sporadic (Es) layer (<em>h</em>’Es and <em>f</em><sub>b</sub>Es, respectively) and of the critical frequency <em>f</em><sub>o</sub>F2 of the F2 layer are considered. For our analysis we make use of data from the Rome ionospheric observatory, located 90 km away from the earthquake epicentre, looking for anomalies up to a couple of months before the mainshock occurrence. Specifically, the variations for 2-3 hours of these parameters with respect to the past 27-day hourly running median are studied in relation to: (a) the ongoing geomagnetic activity during and several hours before the detection of the anomalies, as described by the values of the global a<sub>p</sub> and the auroral AE geomagnetic indices; (b) the earlier-obtained empirical relations for the seismic-ionospheric disturbances relating the earthquake magnitude with the epicentral distance and the anticipation time of the found anomalies. In addition, ionospheric anomalies in the electron density measured over the earthquake preparation region by the CHAllenging Minisatellite Payload (CHAMP) satellite at altitudes of about 320 km are studied in relation to the ionosonde-derived anomalies during the whole period preceding the mainshock occurrence.</p>

scholarly journals Synchronization of geomagnetic and ionospheric disturbances over Kazan station

2017 ◽  
Vol 3 (4) ◽  
pp. 63-73
Author(s):  
Оксана Бархатова ◽  
Oksana Barhatova ◽  
Наталья Косолапова ◽  
Natal'ya Kosolapova ◽  
Николай Бархатов ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Geomagnetic Field ◽  
Critical Frequency ◽  
Ionospheric Disturbances ◽  
Spectral Features ◽  
Quiet Period ◽  
Geomagnetic Disturbances ◽  
Night Time ◽  
Dynamic Spectra ◽  
Solar Wind Parameters

We have analyzed the phenomena which accompany synchronization of night-time ionospheric and geomagnetic disturbances in an ULF range with periods 35–50 min near the mid-latitude station Kazan during a global magnetically quiet period. The comparison between dynamic spectra and wavelet patterns of these disturbances has revealed that spectral features of simultaneous disturbances of the F2-layer critical frequency and H, D, Z geomagnetic field components are similar. By studying spectral features of the F2-layer critical frequency over Kazan and disturbances of the H and D geomagnetic field components at magnetic stations which differ from Kazan in longitude and latitude, we have established that the disturbances considered belong to the class of fast magnetosonic waves. The analysis of solar wind parameters, interplanetary magnetic field (IMF), and values of the auroral index AL in the period under study has shown that this event is associated with IMF Bz component disturbances and occurs during substorm development.

scholarly journals Meteorological controls on glacier mass balance: empirical relations suggested by measurements on glacier de Sarennes, France

1997 ◽  
Vol 43 (143) ◽  
pp. 131-137 ◽  
Author(s):  
C. Vincent ◽  
M. Vallon
Keyword(s):  
Mass Balance ◽  
Time Scale ◽  
Meteorological Data ◽  
Empirical Relation ◽  
Glacier Mass Balance ◽  
Glacier Surface ◽  
Surface Conditions ◽  
The Past ◽  
Empirical Relations

AbstractGlacial mass-balance reconstruction for a long-term time-scale requires knowledge of the relation between climate change and mass-balance fluctuations. A large number of mass-balance reconstructions since the beginning of the century are based on statistical relations between monthly meteorological data and mass balance. The question examined in this paper is: are these relationships reliable enough for long-term time-scale extrapolation? From the glacier de Sarennes long mass-balance observations series, we were surprised to discover large discrepancies between relations resulting from different time periods. The importance of the albedo in relation to ablation and mass balance is highlighted, and it is shown that it is impossible to ignore glacier-surface conditions in establishing the empirical relation between mass-balance fluctuations and climatic variation; to omit this parameter leads to incorrect results for mass-balance reconstruction in the past based on meteorological data.

scholarly journals A review of atmospheric gravity waves and travelling ionospheric disturbances: 1982-1995

1996 ◽  
Vol 14 (9) ◽  
pp. 917-940 ◽  
Author(s):  
K. Hocke ◽  
K. Schlegel
Keyword(s):  
Gravity Waves ◽  
Ionospheric Disturbances ◽  
Atmospheric Gravity Wave ◽  
Atmospheric Gravity Waves ◽  
Travelling Ionospheric Disturbances ◽  
The Past ◽  
Low Latitudes ◽  
Subsequent Propagation ◽  
Atmospheric Gravity ◽  
Inversion Techniques

Abstract. Recent investigations of atmospheric gravity waves (AGW) and travelling ionospheric disturbances (TID) in the Earth\\'s thermosphere and ionosphere are reviewed. In the past decade, the generation of gravity waves at high latitudes and their subsequent propagation to low latitudes have been studied by several global model simulations and coordinated observation campaigns such as the Worldwide Atmospheric Gravity-wave Study (WAGS), the results are presented in the first part of the review. The second part describes the progress towards understanding the AGW/TID characteristics. It points to the AGW/TID relationship which has been recently revealed with the aid of model-data comparisons and by the application of new inversion techniques. We describe the morphology and climatology of gravity waves and their ionospheric manifestations, TIDs, from numerous new observations.

Simultaneous ionosonde investigations of the ionospheric F2 layer critical frequency and peak height at both ends of the geomagnetic tube

2020 ◽  
Vol 1 (1) ◽  
pp. 31-44
Author(s):  
Sergii Panasenko ◽  
Dmytro Kotov ◽  
Taras Zhivolup ◽  
Olexander Koloskov ◽  
Volodymyr Lisachenko
Keyword(s):  
Gravity Waves ◽  
Critical Frequency ◽  
Peak Height ◽  
Ionospheric Disturbances ◽  
Atmospheric Gravity Waves ◽  
Magnetohydrodynamic Waves ◽  
Traveling Ionospheric Disturbances ◽  
Critical Frequency Fof2 ◽  
The Difference ◽  
Atmospheric Gravity

Based on the results of simultaneous ionosonde observations during low solar and weak magnetic activities, a coupling was found between diurnal and quasi-periodic variations in ionospheric parameters over magnetically conjugated regions, where the Ukrainian Antarctic Station (UAS) and Millstone Hill Observatory are located. A significant impact of the summer hemisphere on the nighttime variations of the F2 layer critical frequency foF2 in the magnetically conjugated region in the winter hemisphere was found. The most characteristic manifestation of this impact is the control of foF2 variations over the UAS not by the local sunset (sunrise), but by the sunset (sunrise) over Millstone Hill. It was found that the sunset over Millstone Hill leads to an increase in foF2 over the UAS, while the sunrise leads to a decrease in foF2 with a subsequent sharp increase. Both phenomena are associated with changes in the photoelectron flux from the northern hemisphere, corresponding changes in the electron temperature in the ionosphere above the UAS and the effect of these changes on the compression or rarefaction of the ionospheric plasma and changes in the plasmaspheric fluxes of H + ions. It was shown that the transition from nighttime to daytime conditions over both observation points was characterized by a significant decrease in the F2 layer peak height, and the difference in the values of this ionospheric parameter over Millstone Hill and UAS at night is due to seasonal differences in the thermospheric circulation and the difference in the behavior of the ionospheric parameters in the Northern and Southern hemispheres. Manifestations of atmospheric gravity waves, caused by the passage of local sunrise terminators, as traveling ionospheric disturbances with periods of about 90 and 75 – 120 mins over Millstone Hill and UAS, respectively, were found. These waves were most likely generated in the region located between the ionospheric F1 and F2 layers, where the sharp gradients in the electron and ion densities occur during changes in the intensity of solar radiation. It is confirmed that wave disturbances in atmospheric and ionospheric parameters can be transferred between magnetically conjugated regions by slow magnetohydrodynamic waves generated both at the heights of the ionospheric dynamo region due to the modulation of atmospheric and ionospheric parameters by atmospheric waves and the occurrence of external currents, and at the top of the plasmaspheric tube, where sharp plasma compression and heating or rarefaction and cooling occur during the passage of the solar terminator. Keywords: the ionosphere, F2 region, ionosonde measurements, geomagnetic field tube, magnetoconjugate region coupling, atmospheric gravity waves, traveling ionospheric disturbances, generation of slow magnetohydrodynamic waves

scholarly journals Missing the (Data) Point? Analysis, Advocacy and Accountability in the Monitoring of Attacks on Healthcare in Syria

2020 ◽  
Vol 2 (2) ◽  
pp. 13-21
Author(s):  
Sophie Roborgh
Keyword(s):  
Production Process ◽  
Knowledge Production ◽  
Healthcare Workers ◽  
Data Gathering ◽  
The Past ◽  
Humanitarian Response ◽  
Use Of Data ◽  
Point Analysis ◽  
Data Point ◽  
Data Point Analysis

Monitoring of attacks on healthcare has made great strides in the past decade, even if improvement in information has not necessarily resulted in changes on the ground. However, important questions on the knowledge production process continue to be under-explored, including those pertaining to the objectives of monitoring efforts. What does our data actually tell us? Are we missing the (data) point? This paper explores several monitoring mechanisms, and analyses the limitations of the data-gathering exercise, affecting the ability of healthcare workers to share their experiences. By drawing on the experiences of those involved in the medical-humanitarian response in non-government controlled areas in Syria, these dynamics are further brought to the fore, advocating for a more discerning approach in the use of data for such disparate goals as analysis on patterns of attacks (and their implications), advocacy, and accountability.

scholarly journals Ionospheric disturbances over East Asia during intense December magnetic storms of 2006 and 2015: similarities and differences

2018 ◽  
Vol 4 (3) ◽  
pp. 28-42 ◽  
Author(s):  
Нина Золотухина ◽  
Nina Zolotukhina ◽  
Владимир Куркин ◽  
Vladimir Kurkin ◽  
Неля Полех ◽  
...  
Keyword(s):  
East Asia ◽  
Critical Frequency ◽  
Geomagnetic Storms ◽  
Initial Conditions ◽  
Ionospheric Disturbance ◽  
Magnetic Storms ◽  
Electron Content ◽  
Ionospheric Disturbances ◽  
Early Recovery ◽  
Total Electron

Using data from ionosondes, located in East Asia, and total electron content maps, we have made a comparative analysis of ionospheric disturbances associated with the intense geomagnetic storms of December 14–16, 2006 and December 19–22, 2015. These storms had almost equal peak intensities (Dstmin=–162 and –155 nT), but different durations of the main phases (2.5 and 19 hr). At the beginning of both the storms, the region under study was located in the vicinity of the midnight meridian. Ionospheric responses to magnetic storms differed in: i) an increase in the F2-layer critical frequency at subauroral latitudes, caused by an increase in auroral precipitation, during the initial phase of the former storm and the absence of this effect in the latter; (ii) a sharp drop in the critical frequency in the evening hours of the main phase of the latter storm, caused by a shift of the main ionospheric trough to lower latitudes, and the absence of this effect during the former storm; (iii) generation of a short-term positive disturbance observed at subauroral latitudes only in the early recovery phase of the former storm after the negative ionospheric disturbance. During both the storms at middle latitudes there were positive disturbances and wave-like fluctuations of the critical frequency which increased in the vicinity of the dawn meridian. The main causes of the differences between the ionospheric storms are shown to be the differences between the initial conditions of the magnetosphere–ionosphere system and durations of the main phases of magnetic storms.

scholarly journals Ionospheric transients observed at mid-latitudes prior to earthquake activity in Central Italy

2010 ◽  
Vol 10 (6) ◽  
pp. 1197-1208 ◽  
Author(s):  
P. Nenovski ◽  
Ch. Spassov ◽  
M. Pezzopane ◽  
U. Villante ◽  
M. Vellante ◽  
...  
Keyword(s):  
Gravity Waves ◽  
Critical Frequency ◽  
Central Italy ◽  
Ionospheric Disturbances ◽  
Earthquake Activity ◽  
Acoustic Gravity Waves ◽  
F Region ◽  
E Region ◽  
Sporadic E ◽  
Layer Development

Abstract. Ionograms from Rome (41.8N, 12.5E) and Sofia (42.4N, 23.2E) ionospheric stations during earthquake (EQ) activity with magnitude (M) between 5 and 6 in Central Italy are analyzed. It is found that several ionospheric disturbances occur in the intermediate E-F region before the EQ shock. In fact, besides sporadic E (Es) layer development (of type h) of short duration (transients), fmin increase, trace gaps near the critical frequencies, and E region trace disappearance are also observed within one to three hours before the EQ shock. Before the EQ shocks we find that the F2 region parameters are practically undisturbed. The only exception is the so-called fork trace that appears mostly near the critical frequency of the F2 region. Acoustic gravity waves (AGW) are suggested as one of the possible sources of transients observed in the ionosphere before the EQ shock.

Sign in / Sign up

Export Citation Format

Share Document