Schumann resonance intensity as a precursor for warm ENSO episodes

2020 ◽  
Author(s):  
Gabriella Satori ◽  
Tamas Bozoki ◽  
Earle Williams ◽  
Colin Price ◽  
Anirban Guha ◽  
...  
Keyword(s):  
Low Frequency ◽  
Intensity Variation ◽  
Lightning Activity ◽  
Medium Size ◽  
Percentage Increase ◽  
Efficient Tool ◽  
Schumann Resonances ◽  
The Earth ◽  
Electromagnetic Resonances ◽  
Systematic Behavior

<p>Schumann resonances (SR) are the global electromagnetic resonances of the Earth-ionosphere cavity and constitute the extremely low frequency (< 100 Hz) radiation of the worldwide lightning activity (Schumann, 1952). The recording of SR intensity at a few distant SR stations is an efficient tool to monitor the global lightning. We present the variations of SR intensity in the transition months preceding the warm ENSO episodes for the two super El Niño events in 1997/98 and 2015/16 as well as for the two medium size El Niño periods in 2001/02 and 2008/09  based on SR observations at multiple locations.: Nagycenk, Hungary (47.6N, 16.7E);  Hornsund, Svalbard (77.0N, 15.6E);  Eskdalemuir, UK (55.3N, 3.2W);  Alberta, Canada (51.9N, 111.5W);  Boulder Creek, USA (37.2N, 122.1W).</p><p>A remarkable increase in SR intensity is documented two-three months before or just at the beginning of El Niño episodes as compared with the SR intensity in the same months of the preceding La Niña (or non-ENSO) phase for all cases studied here. The percentage increase in SR intensity depends on the amplitude of the warm ENSO period, and is consistently higher for the two super El Niño events. The enhanced SR intensity indicates a worldwide response of global lightning activity. Increased atmospheric instability due to the land-ocean thermal interaction during the transition interval could be responsible for the intensification of lightning activity. This systematic behavior may have been overlooked in earlier studies that compared lightning activity in the integrated ‘cold’ and the ‘warm’ phases, but without exploring the transitional variation. Our results suggest that the SR intensity variation on the interannual time scale acts a precursor for the occurrence of warm ENSO episode.</p>

scholarly journals Multipoint observations of Ionospheric Alfvén Resonance

2016 ◽  
Vol 6 (1) ◽  
pp. 45-49 ◽  
Author(s):  
N. Baru ◽  
A. Koloskov ◽  
Y. Yampolsky ◽  
R. Rakhmatulin
Keyword(s):  
Low Frequency ◽  
Solar Observatory ◽  
Resonance Structure ◽  
Data Series ◽  
Annual Data ◽  
The Earth ◽  
Electromagnetic Resonances ◽  
Global Nature ◽  
Propagation Medium ◽  
Magnetic Station

Among the processes that form properties of the geospace in the circumterrestrial plasma the electromagnetic resonances of the Earth, such as Schummann Resonance (SR) and Ionospheric Alfvén Resonance (IAR) are of great importance. IAR is more localized in space than SR and its properties largely depend on the characteristics of the propagation medium. In contrast to the SR, which has global nature and which is continuously observable at any time of the day, IAR signals are registered mostly during the nighttime and demonstrate more variability of the parameters than SR signals. At the Earth surface IAR is registered as Spectral Resonance Structure of the natural electromagnetic noise at frequency range 0.1-40 Hz. In this work we studied an influence of the environment characteristics on IAR parameters by the means of multipoint observations. Annual data series recorded at Ukrainian Antarctic Station 'Akademik Vernadsky', Low Frequency Observatory of the Institute of Radio Astronomy near Kharkov (Ukraine) and magnetic station of Sayan Solar Observatory Mondy near Irkutsk (Russia) were used for the analysis. We investigated the behaviour of IAR parameters, such as probability of resonance lines registration and frequency spacing $\Delta F$, for annual and diurnal intervals. These parameters were compared with characteristics of the ionosphere above all of the observation points and geomagnetic activity.

scholarly journals Study of the Periodicities of Lightning Activity in Three Main Thunderstorm Centers Based on Schumann Resonance Measurements

2009 ◽  
Vol 137 (12) ◽  
pp. 4401-4409 ◽  
Author(s):  
Zenon Nieckarz ◽  
Stanisław Zięba ◽  
Andrzej Kułak ◽  
Adam Michalec
Keyword(s):  
Power Spectrum ◽  
Activity Index ◽  
Low Frequency ◽  
Lightning Activity ◽  
Time Interval ◽  
Frequency Range ◽  
Maritime Continent ◽  
Schumann Resonances ◽  
Level Of Activity ◽  
Time Variations

Abstract Time variations of lightning activity in the three main tropical thunderstorm centers located in the Maritime Continent (Pakistan, India, Southeast Asia, Indonesia, and Australia), Africa, and the Americas are analyzed using a lightning activity index IRS, which is calculated from the resonances of magnetic field in the extremely low frequency range—the Schumann resonances—which were observed at Hylaty station (Poland) in the time interval July 2005–May 2006. Power spectrum analysis of the IRS series is carried out for this time interval. The annual and semiannual variations are shown in all of the series together with the following characteristic periodicities: 45 (Madden–Julian oscillation), 17.6, 13.5, and 4.8 days, seen mainly in the series describing the lightning activity of the Maritime Continent. In addition, maps of the dynamical power spectrum are constructed. They present variability both in the values of characteristic periods 26–30, 17–22, 12–14, 9–10, and 5–7 days and in their duration. During the studied time interval, according to these indices, the African center was the most active, whereas the American and Maritime Continent centers showed a similar level of activity. The largest differences among the centers were observed in the summer months in the Northern Hemisphere.

Analysis of Remote Sensing based Vegetation Indices (VIs) for Unmanned Aerial System (UAS): A Review

2020 ◽  
Vol 3 (2) ◽  
pp. 58-73
Author(s):  
Vijay Bhagat ◽  
Ajaykumar Kada ◽  
Suresh Kumar
Keyword(s):  
Remote Sensing ◽  
Spatial Data ◽  
Satellite Remote Sensing ◽  
Vegetation Indices ◽  
Unmanned Aerial System ◽  
Sustainable Land Management ◽  
Efficient Tool ◽  
Site Specific ◽  
The Earth ◽  
Interesting Area

Unmanned Aerial System (UAS) is an efficient tool to bridge the gap between high expensive satellite remote sensing, manned aerial surveys, and labors time consuming conventional fieldwork techniques of data collection. UAS can provide spatial data at very fine (up to a few mm) and desirable temporal resolution. Several studies have used vegetation indices (VIs) calculated from UAS based on optical- and MSS-datasets to model the parameters of biophysical units of the Earth surface. They have used different techniques of estimations, predictions and classifications. However, these results vary according to used datasets and techniques and appear very site-specific. These existing approaches aren’t optimal and applicable for all cases and need to be tested according to sensor category and different geophysical environmental conditions for global applications. UAS remote sensing is a challenging and interesting area of research for sustainable land management.

CORRELATION OF LOCAL LIGHTNING ACTIVITY WITH EXTRA LOW FREQUENCY DETECTOR FOR SCHUMANN RESONANCE MEASUREMENTS

2021 ◽  
pp. 147671
Author(s):  
G. Tatsis ◽  
A. Sakkas ◽  
V. Christofilakis ◽  
G. Baldoumas ◽  
S.K. Chronopoulos ◽  
...  
Keyword(s):  
Low Frequency ◽  
Lightning Activity ◽  
Schumann Resonance ◽  
Frequency Detector

Foreshock ULF fluctuations near the Moon: THEMIS observations

2021 ◽  
Author(s):  
Anna Salohub ◽  
Jana Šafránková ◽  
Zdeněk Němeček
Keyword(s):  
Solar Wind ◽  
Rest Frame ◽  
Low Frequency ◽  
Solar Wind Plasma ◽  
Turbulent Plasma ◽  
Bow Shock ◽  
Ulf Waves ◽  
The Moon ◽  
Shock Surface ◽  
The Earth

<p>The foreshock is a region filled with a turbulent plasma located upstream the Earth’s bow shock where interplanetary magnetic field (IMF) lines are connected to the bow shock surface. In this region, ultra-low frequency (ULF) waves are generated due to the interaction of the solar wind plasma with particles reflected from the bow shock back into the solar wind. It is assumed that excited waves grow and they are convected through the solar wind/foreshock, thus the inner spacecraft (close to the bow shock) would observe larger wave amplitudes than the outer (far from the bow shock) spacecraft. The paper presents a statistical analysis of excited ULF fluctuations observed simultaneously by two closely separated THEMIS spacecraft orbiting the Moon under a nearly radial IMF. We found that ULF fluctuations (in the plasma rest frame) can be characterized as a mixture of transverse and compressional modes with different properties at both locations. We discuss the growth and/or damping of ULF waves during their propagation.</p>

WORKING DEPTHS FOR LOW FREQUENCY ELECTRICAL PROSPECTING

Geophysics ◽  
1945 ◽  
Vol 10 (1) ◽  
pp. 63-75 ◽  
Author(s):  
William Bradley Lewis
Keyword(s):  
Low Frequency ◽  
Electrical Measurements ◽  
The Earth ◽  
Electrical Prospecting

Electrical measurements were made on the surface of the earth with low frequency commutated current using nineteen separate frequencies and six electrode separations. Analysis of the data indicates that there is an effect of appreciable magnitude attributable to an interface 6000 feet below the surface.

ON THE THEORY OF SCHUMANN RESONANCES IN THE EARTH–IONOSPHERE CAVITY

1964 ◽  
Vol 42 (4) ◽  
pp. 575-582 ◽  
Author(s):  
James R. Wait
Keyword(s):  
Cavity Resonator ◽  
Current Work ◽  
Alternative Derivation ◽  
Schumann Resonances ◽  
The Earth ◽  
Cavity Resonances ◽  
Concentric Region ◽  
The Subject

The concept that the concentric region between the earth and the ionosphere acts as a cavity resonator was proposed by Schumann over a decade ago. It is the purpose of this paper to review the theory of these cavity resonances. Some of the assumptions used in current work on the subject are also discussed. An alternative derivation is presented which appears to be more general than any given heretofore.

scholarly journals Precision Pulsar Timing with NASA's Deep Space Network

2015 ◽  
Vol 11 (A29B) ◽  
pp. 367-369
Author(s):  
Lawrence Teitelbaum ◽  
Walid Majid ◽  
Manuel M. Franco ◽  
Daniel J. Hoppe ◽  
Shinji Horiuchi ◽  
...  
Keyword(s):  
Low Frequency ◽  
Radio Waves ◽  
Deep Space ◽  
Radio Pulsars ◽  
Deep Space Network ◽  
Space Network ◽  
The Earth ◽  
Pulsar Timing ◽  
Initial Results ◽  
Stable Rotation

AbstractMillisecond pulsars (MSPs) are a class of radio pulsars with extremely stable rotation. Their excellent timing stability can be used to study a wide variety of astrophysical phenomena. In particular, a large sample of these pulsars can be used to detect low-frequency gravitational waves. We have developed a precision pulsar timing backend for the NASA Deep Space Network (DSN), which will allow the use of short gaps in tracking schedules to time pulses from an ensemble of MSPs. The DSN operates clusters of large dish antennas (up to 70-m in diameter), located roughly equidistant around the Earth, for communication and tracking of deep-space spacecraft. The backend system will be capable of removing entirely the dispersive effects of propagation of radio waves through the interstellar medium in real-time. We will describe our development work, initial results, and prospects for future observations over the next few years.

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