scholarly journals Dynamical Complexity of the 2015 St. Patrick’s Day Magnetic Storm at Swarm Altitudes Using Entropy Measures

Entropy ◽  
2020 ◽  
Vol 22 (5) ◽  
pp. 574 ◽  
Author(s):  
Constantinos Papadimitriou ◽  
Georgios Balasis ◽  
Adamantia Zoe Boutsi ◽  
Ioannis A. Daglis ◽  
Omiros Giannakis ◽  
...  
Keyword(s):  
Time Series ◽  
Magnetic Storm ◽  
Low Earth Orbit ◽  
Topside Ionosphere ◽  
Dynamical Response ◽  
Satellite Mission ◽  
Dynamical Complexity ◽  
Coupling System ◽  
Entropy Measures ◽  
Cycle 24

The continuously expanding toolbox of nonlinear time series analysis techniques has recently highlighted the importance of dynamical complexity to understand the behavior of the complex solar wind–magnetosphere–ionosphere–thermosphere coupling system and its components. Here, we apply new such approaches, mainly a series of entropy methods to the time series of the Earth’s magnetic field measured by the Swarm constellation. We show successful applications of methods, originated from information theory, to quantitatively study complexity in the dynamical response of the topside ionosphere, at Swarm altitudes, focusing on the most intense magnetic storm of solar cycle 24, that is, the St. Patrick’s Day storm, which occurred in March 2015. These entropy measures are utilized for the first time to analyze data from a low-Earth orbit (LEO) satellite mission flying in the topside ionosphere. These approaches may hold great potential for improved space weather nowcasts and forecasts.

Dynamical Complexity of Magnetic Storms at Swarm Altitudes Using Entropy Measures

2020 ◽  
Author(s):  
Constantinos Papadimitriou ◽  
Georgios Balasis ◽  
Adamantia-Zoe Boutsi ◽  
Omiros GIannakis ◽  
Anastasios Anastasiadis ◽  
...  
Keyword(s):  
Information Theory ◽  
Time Series ◽  
Magnetic Storms ◽  
Topside Ionosphere ◽  
Dynamical Response ◽  
Electromagnetic Environment ◽  
Dynamical Complexity ◽  
Coupling System ◽  
Entropy Measures ◽  
Earth’S System

<p>Recently, many novel concepts originated in dynamical systems or information theory have been developed, partly motivated by specific research questions linked to geosciences, and found a variety of different applications. This continuously extending toolbox of nonlinear time series analysis highlights the importance of the dynamical complexity to understand the behavior of the complex solar wind – magnetosphere – ionosphere - thermosphere coupling system and its components. Here, we propose to apply such new approaches, mainly a series of entropy methods to the time series of the Earth's magnetic field measured by the Swarm constellation. Swarm is an ESA mission launched on November 22, 2013, comprising three satellites at low Earth polar orbits. The mission delivers data that provide new insight into the Earth's system by improving our understanding of the Earth's interior as well as the near-Earth electromagnetic environment. We show successful applications of methods originated in information theory to quantitatively studying complexity in the dynamical response of the topside ionosphere, at Swarm altitudes, focusing on the most intense magnetic storms of the present solar cycle.</p>

scholarly journals An initial ULF wave index derived from 2 years of Swarm observations

2018 ◽  
Vol 36 (2) ◽  
pp. 287-299 ◽  
Author(s):  
Constantinos Papadimitriou ◽  
Georgios Balasis ◽  
Ioannis A. Daglis ◽  
Omiros Giannakis
Keyword(s):  
Methodological Approach ◽  
Low Frequency ◽  
Low Earth Orbit ◽  
Topside Ionosphere ◽  
Satellite Mission ◽  
Time Frequency ◽  
Ulf Wave ◽  
Magnetic Field Model ◽  
Swarm Satellite ◽  
Level 2

Abstract. The ongoing Swarm satellite mission provides an opportunity for better knowledge of the near-Earth electromagnetic environment. Herein, we use a new methodological approach for the detection and classification of ultra low-frequency (ULF) wave events observed by Swarm based on an existing time-frequency analysis (TFA) tool and utilizing a state-of-the-art high-resolution magnetic field model and Swarm Level 2 products (i.e., field-aligned currents – FACs – and the Ionospheric Bubble Index – IBI). We present maps of the dependence of ULF wave power with magnetic latitude and magnetic local time (MLT) as well as geographic latitude and longitude from the three satellites at their different locations in low-Earth orbit (LEO) for a period spanning 2 years after the constellation's final configuration. We show that the inclusion of the Swarm single-spacecraft FAC product in our analysis eliminates all the wave activity at high altitudes, which is physically unrealistic. Moreover, we derive a Swarm orbit-by-orbit Pc3 wave (20–100 MHz) index for the topside ionosphere and compare its values with the corresponding variations of solar wind variables and geomagnetic activity indices. This is the first attempt, to our knowledge, to derive a ULF wave index from LEO satellite data. The technique can be potentially used to define a new Level 2 product from the mission, the Swarm ULF wave index, which would be suitable for space weather applications. Keywords. Space plasma physics (waves and instabilities)

scholarly journals ULF wave activity during the 2003 Halloween superstorm: multipoint observations from CHAMP, Cluster and Geotail missions

2012 ◽  
Vol 30 (12) ◽  
pp. 1751-1768 ◽  
Author(s):  
G. Balasis ◽  
I. A. Daglis ◽  
E. Zesta ◽  
C. Papadimitriou ◽  
M. Georgiou ◽  
...  
Keyword(s):  
Low Frequency ◽  
Wave Activity ◽  
Low Earth Orbit ◽  
Topside Ionosphere ◽  
Ulf Waves ◽  
Satellite Mission ◽  
Ulf Wave ◽  
Activity Frequency ◽  
Field Lines ◽  
First Time

Abstract. We examine data from a topside ionosphere and two magnetospheric missions (CHAMP, Cluster and Geotail) for signatures of ultra low frequency (ULF) waves during the exceptional 2003 Halloween geospace magnetic storm, when Dst reached ~−380 nT. We use a suite of wavelet-based algorithms, which are a subset of a tool that is being developed for the analysis of multi-instrument multi-satellite and ground-based observations to identify ULF waves and investigate their properties. Starting from the region of topside ionosphere, we first present three clear and strong signatures of Pc3 ULF wave activity (frequency 15–100 mHz) in CHAMP tracks. We then expand these three time intervals for purposes of comparison between CHAMP, Cluster and Geotail Pc3 observations but also to be able to search for Pc4–5 wave signatures (frequency 1–10 mHz) into Cluster and Geotail measurements in order to have a more complete picture of the ULF wave occurrence during the storm. Due to the fast motion through field lines in a low Earth orbit (LEO) we are able to reliably detect Pc3 (but not Pc4–5) waves from CHAMP. This is the first time, to our knowledge, that ULF wave observations from a topside ionosphere mission are compared to ULF wave observations from magnetospheric missions. Our study provides evidence for the occurrence of a number of prominent ULF wave events in the Pc3 and Pc4–5 bands during the storm and offers a platform to study the wave evolution from high altitudes to LEO. The ULF wave analysis methods presented here can be applied to observations from the upcoming Swarm multi-satellite mission of ESA, which is anticipated to enable joint studies with the Cluster mission.

scholarly journals Geomagnetic Virtual Observatories: monitoring geomagnetic secular variation with the Swarm satellites

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Magnus D. Hammer ◽  
Grace A. Cox ◽  
William J. Brown ◽  
Ciarán D. Beggan ◽  
Christopher C. Finlay
Keyword(s):  
Time Series ◽  
Secular Variation ◽  
Geomagnetic Field ◽  
Time Windows ◽  
Low Earth Orbit ◽  
Data Selection ◽  
Spherical Harmonic Analysis ◽  
Core Field ◽  
The Core ◽  
Swarm Satellites

AbstractWe present geomagnetic main field and secular variation time series, at 300 equal-area distributed locations and at 490 km altitude, derived from magnetic field measurements collected by the three Swarm satellites. These Geomagnetic Virtual Observatory (GVO) series provide a convenient means to globally monitor and analyze long-term variations of the geomagnetic field from low-Earth orbit. The series are obtained by robust fits of local Cartesian potential field models to along-track and East–West sums and differences of Swarm satellite data collected within a radius of 700 km of the GVO locations during either 1-monthly or 4-monthly time windows. We describe two GVO data products: (1) ‘Observed Field’ GVO time series, where all observed sources contribute to the estimated values, without any data selection or correction, and (2) ‘Core Field’ GVO time series, where additional data selection is carried out, then de-noising schemes and epoch-by-epoch spherical harmonic analysis are applied to reduce contamination by magnetospheric and ionospheric signals. Secular variation series are provided as annual differences of the Core Field GVOs. We present examples of the resulting Swarm GVO series, assessing their quality through comparisons with ground observatories and geomagnetic field models. In benchmark comparisons with six high-quality mid-to-low latitude ground observatories we find the secular variation of the Core Field GVO field intensities, calculated using annual differences, agrees to an rms of 1.8 nT/yr and 1.2 nT/yr for the 1-monthly and 4-monthly versions, respectively. Regular sampling in space and time, and the availability of data error estimates, makes the GVO series well suited for users wishing to perform data assimilation studies of core dynamics, or to study long-period magnetospheric and ionospheric signals and their induced counterparts. The Swarm GVO time series will be regularly updated, approximately every four months, allowing ready access to the latest secular variation data from the Swarm satellites.

scholarly journals From GPS Receiver to GNSS Reflectometry Payload Development for the Triton Satellite Mission

2021 ◽  
Vol 13 (5) ◽  
pp. 999
Author(s):  
Yung-Fu Tsai ◽  
Wen-Hao Yeh ◽  
Jyh-Ching Juang ◽  
Dian-Syuan Yang ◽  
Chen-Tsung Lin
Keyword(s):  
Satellite System ◽  
Low Earth Orbit ◽  
Export Control ◽  
Navigation Systems ◽  
Gps Receiver ◽  
Design Development ◽  
Satellite Mission ◽  
Essential Components ◽  
Gnss Reflectometry ◽  
Global Navigation Satellite

The global positioning system (GPS) receiver has been one of the most important navigation systems for more than two decades. Although the GPS system was originally designed for near-Earth navigation, currently it is widely used in highly dynamic environments (such as low Earth orbit (LEO)). A space-capable GPS receiver (GPSR) is capable of providing timing and navigation information for spacecraft to determine the orbit and synchronize the onboard timing; therefore, it is one of the essential components of modern spacecraft. However, a space-grade GPSR is technology-sensitive and under export control. In order to overcome export control, the National Space Organization (NSPO) in Taiwan completed the development of a self-reliant space-grade GPSR in 2014. The NSPO GPSR, built in-house, has passed its qualification tests and is ready to fly onboard the Triton satellite. In addition to providing navigation, the GPS/global navigation satellite system (GNSS) is facilitated to many remote sensing missions, such as GNSS radio occultation (GNSS-RO) and GNSS reflectometry (GNSS-R). Based on the design of the NSPO GPSR, the NSPO is actively engaged in the development of the Triton program (a GNSS reflectometry mission). In a GNSS-R mission, the reflected signals are processed to form delay Doppler maps (DDMs) so that various properties (including ocean surface roughness, vegetation, soil moisture, and so on) can be retrieved. This paper describes not only the development of the NSPO GPSR but also the design, development, and special features of the Triton’s GNSS-R mission. Moreover, in order to verify the NSPO GNSS-R receiver, ground/flight tests are deemed essential. Then, data analyses of the airborne GNSS-R tests are presented in this paper.

scholarly journals Topside Ionosphere and Plasmasphere Modelling Using GNSS Radio Occultation and POD Data

2021 ◽  
Vol 13 (8) ◽  
pp. 1559
Author(s):  
Fabricio S. Prol ◽  
M. Mainul Hoque
Keyword(s):  
Solar Activity ◽  
Electron Density ◽  
Radio Occultation ◽  
Geomagnetic Latitude ◽  
Low Earth Orbit ◽  
Activity Level ◽  
Topside Ionosphere ◽  
Electron Content ◽  
Total Electron ◽  
Solar Activity Level

A 3D-model approach has been developed to describe the electron density of the topside ionosphere and plasmasphere based on Global Navigation Satellite System (GNSS) measurements onboard low Earth orbit satellites. Electron density profiles derived from ionospheric Radio Occultation (RO) data are extrapolated to the upper ionosphere and plasmasphere based on a linear Vary-Chap function and Total Electron Content (TEC) measurements. A final update is then obtained by applying tomographic algorithms to the slant TEC measurements. Since the background specification is created with RO data, the proposed approach does not require using any external ionospheric/plasmaspheric model to adapt to the most recent data distributions. We assessed the model accuracy in 2013 and 2018 using independent TEC data, in situ electron density measurements, and ionosondes. A systematic better specification was obtained in comparison to NeQuick, with improvements around 15% in terms of electron density at 800 km, 26% at the top-most region (above 10,000 km) and 26% to 55% in terms of TEC, depending on the solar activity level. Our investigation shows that the developed model follows a known variation of electron density with respect to geographic/geomagnetic latitude, altitude, solar activity level, season, and local time, revealing the approach as a practical and useful tool for describing topside ionosphere and plasmasphere using satellite-based GNSS data.

scholarly journals Behavior of the topside ionosphere during a great magnetic storm

1968 ◽  
Vol 16 (5) ◽  
pp. 653-663 ◽  
Author(s):  
S.J. Bauer ◽  
B.V. Krishnamurthy
Keyword(s):  
Magnetic Storm ◽  
Topside Ionosphere

scholarly journals Observatory crustal magnetic biases during CHAMP satellite mission

2015 ◽  
Vol 7 (1) ◽  
pp. 495-508
Author(s):  
G. Verbanac ◽  
M. Mandea ◽  
M. Bandić ◽  
S. Subašić
Keyword(s):  
Time Series ◽  
External Field ◽  
Personal Communication ◽  
Field Pattern ◽  
Monthly Means ◽  
Satellite Mission ◽  
Champ Satellite ◽  
Annual Variations ◽  
Oscillatory Pattern ◽  
Short Period

Abstract. Taking advantage of nine years of CHAMP satellite mission (June 2000–August 2009), we investigate the temporal evolution of the observatory monthly crustal magnetic biases. To determine biases we compute X (northward), Y (eastward) and Z (vertically downward) monthly means from 42 observatory one-minute or hourly values, and compare them to synthetic monthly means obtained from a GRIMM3 core field model (V. Lesur, personal communication, 2014). Both short period variations and long term trends in the monthly bias time series are analyzed. A comparison with biases based on MAGSAT and Ørsted satellite data, related to the 1979.92 and 1992.92 epochs is performed. Generally, the larger biases averaged over nine years and the larger differences between biases based on different models are found in Z component. This can be the signature of the induced magnetic fields. Although annual trends in most bias series are observed, no clear evidence that the constant crustal field changed significantly over the studied period is found. Time series of monthly biases exhibit distinct oscillatory pattern in the whole time span, which we assign to the external field contributions. The amplitudes of these variations are linked with the phase of the solar cycle, being significantly larger in the period 2000–2005 than in the period 2006–2009. Clear semi-annual variations are evident in all components, with extremes in spring and fall months of each year. Common external field pattern is found for European monthly biases. A dependence of the bias monthly variations on geomagnetic latitudes is not found for the non-European observatories. The results from this study represent a base to further exploit the observatory and repeat stations magnetic biases together with the data from the new satellite mission SWARM.

scholarly journals Prediction of magnetic storm events using the <i>D<sub>st</sub></i> index

2005 ◽  
Vol 12 (6) ◽  
pp. 799-806 ◽  
Author(s):  
V. V. Anh ◽  
Z. G. Yu ◽  
J. A. Wanliss ◽  
S. M. Watson
Keyword(s):  
Time Series ◽  
Magnetic Storm ◽  
Iterated Function System ◽  
Numerical Results ◽  
Function System ◽  
Storm Events ◽  
Dst Index ◽  
Measure Representation ◽  
Iterated Function

Abstract. This paper provides a method to predict magnetic storm events based on the time series of the Dst index over the period 1981-2002. This method is based on the multiple scaling of the measure representation of the Dst time series. This measure is modeled as a recurrent iterated function system, which leads to a method to predict storm patterns included in its attractor. Numerical results are provided to evaluate the performance of the method in outside-sample forecasts.

Synoptic maps in three wavelengths of the Chromospheric Telescope

2018 ◽  
Vol 14 (A30) ◽  
pp. 339-341
Author(s):  
Andrea Diercke ◽  
Carsten Denker
Keyword(s):  
Time Series ◽  
Solar Cycle ◽  
Solar Disk ◽  
The Sun ◽  
Observational Period ◽  
Quiet Sun ◽  
Solar Cycle 24 ◽  
Cycle 24 ◽  
Spectral Ranges ◽  
Full Disk

Abstracthe Chromospheric Telescope (ChroTel) observes the entire solar disk since 2011 in three different chromospheric wavelengths: Hα, Ca ii K, and He i. The instrument records full-disk images of the Sun every three minutes in these different spectral ranges. The ChroTel observations cover the rising and decaying phase of solar cycle 24. We started analyzing the ChroTel time-series and created synoptic maps of the entire observational period in all three wavelength bands. The maps will be used to analyze the poleward migration of quiet-Sun filaments in solar cycle 24.

Sign in / Sign up

Export Citation Format

Share Document