Study of the annual changes of global lightning distribution and frequency variations of the first Schumann resonance mode

1995 ◽  
Vol 57 (11) ◽  
pp. 1345-1348 ◽  
Author(s):  
A.P. Nickolaenko ◽  
L.M. Rabinowicz
Keyword(s):  
Resonance Mode ◽  
Schumann Resonance ◽  
Annual Changes ◽  
Frequency Variations

scholarly journals Schumann resonance frequency variations observed in magnetotelluric data recorded from Garhwal Himalayan region India

2009 ◽  
Vol 27 (9) ◽  
pp. 3497-3507 ◽  
Author(s):  
R. Chand ◽  
M. Israil ◽  
J. Rai
Keyword(s):  
Magnetic Field ◽  
Time Series ◽  
Resonance Frequency ◽  
Himalayan Region ◽  
Series Data ◽  
Frequency Variation ◽  
Schumann Resonance ◽  
Magnetotelluric Data ◽  
Electric And Magnetic Field ◽  
Frequency Variations

Abstract. Schumann resonance (SR) frequency variation has been studied using Magnetotelluric (MT) data recorded in one of the world's toughest and generally inaccessible Himalayan terrain for the first time in the author's knowledge. The magnetotelluric data, in the form of orthogonal time varying electric and magnetic field components (Ex, Ey, Bx and By), recorded during 10 March–23 May 2006, in the Himalayan region, India, at elevations between 1228–2747 m above mean sea level (amsl), were used to study the SR frequency variation. Electromagnetic field components, in the form of time series, were recorded at 64 Hz sampling frequency at a site located away from the cultural noise. Spectral analysis of time series data, at a frequency resolution of 0.03 Hz, has been performed using Fast Fourier Transform (FFT) algorithm. Spectral stabilization in three Schumann resonance modes is achieved by averaging the power spectral magnitude of 32 data segments, each with 2048 sample data. Amplitude variation in the Schumann resonance frequency associated with day-night, sunrise and terminator effect was observed. Average diurnal variation in the first three Schumann resonance frequencies associated with magnetic field components is presented. The maximum frequency variation of about 0.3, 0.4 and 0.7 Hz was observed in the first, second and third mode, respectively. The frequency variations observed in electric and magnetic field components also show phase shift and varying attenuation. The SR frequency variation has been used to define the ionospheric electron density variation in the Himalayan region, India.

scholarly journals The iterative complex demodulation applied on short and long Schumann resonance measured sequences

2014 ◽  
Vol 44 (4) ◽  
pp. 313-328 ◽  
Author(s):  
Adriena Ondrášková ◽  
Sebastián Ševčík
Keyword(s):  
Solar Cycle ◽  
Precise Determination ◽  
Schumann Resonance ◽  
Modal Frequency ◽  
Complex Demodulation ◽  
Function Fitting ◽  
Cycle Maximum ◽  
Short Signal ◽  
Frequency Variations

Abstract The precise determination of instantaneous frequency of Schumann resonance (SR) modes, with the possibility of application to relatively short signal sequences, seems to be important for detailed analysis of SR modal frequency variations. Contrary to commonly used method of obtaining modal frequencies by the Lorentz function fitting of DFT spectra, we employ the complex demodulation (CD) method in iterated form. Results of iterated CD method applied on short and long measured sequences are compared. Results for SR signals as well as the comparison with Lorentz function fitting are presented. Decrease of frequencies of all first four SR modes from the solar cycle maximum to solar cycle minimum has been found using also the CD method.

scholarly journals Anomalous effect in Schumann resonance phenomena observed in Japan, possibly associated with the Chi-chi earthquake in Taiwan

2005 ◽  
Vol 23 (4) ◽  
pp. 1335-1346 ◽  
Author(s):  
M. Hayakawa ◽  
K. Ohta ◽  
A. P. Nickolaenko ◽  
Y. Ando
Keyword(s):  
Frequency Shift ◽  
Main Shock ◽  
Peak Frequency ◽  
Resonance Mode ◽  
Resonance Phenomenon ◽  
Meridian Plane ◽  
Schumann Resonance ◽  
Anomalous Effect ◽  
Arrival Angle ◽  
Small Magnitude

Abstract. The Schumann resonance phenomenon has been monitored at Nakatsugawa (near Nagoya) in Japan since the beginning of 1999, and due to the occurance of a severe earthquake (so-called Chi-chi earthquake) on 21 September 1999 in Taiwan we have examined our Schumann resonance data at Nakatsugawa during the entire year of 1999. We have found a very anomalous effect in the Schumann resonance, possibly associated with two large land earthquakes (one is the Chi-chi earthquake and another one on 2 November 1999 (Chia-yi earthquake) with a magnitude again greater than 6.0). Conspicuous effects are observed for the larger Chi-chi earthquake, so that we summarize the characteristics for this event. The anomaly is characterized mainly by the unusual increase in amplitude of the fourth Schumann resonance mode and a significant frequency shift of its peak frequency (~1.0Hz) from the conventional value on the By magnetic field component which is sensitive to the waves propagating in the NS meridian plane. Anomalous Schumann resonance signals appeared from about one week to a few days before the main shock. Secondly, the goniometric estimation of the arrival angle of the anomalous signal is found to coincide with the Taiwan azimuth (the unresolved dual direction indicates toward South America). Also, the pulsed signals, such as the Q-bursts, were simultaneously observed with the "carrier" frequency around the peak frequency of the fourth Schumann resonance mode. The anomaly for the second event for the Chia-yi earthquake on 2 November had much in common. But, most likely due to a small magnitude, the anomaly appears one day before and lasts until one day after the main shock, with the enhancement at the fourth Schumann resonance mode being smaller in amplitude than the case of the Chi-chi earthquake. Yet, the other characteristics, including the goniometric direction finding result, frequency shift, etc., are nearly the same. Although the emphasis of the present study is made on experimental aspects, a possible generation mechanism for this anomaly is discussed in terms of the ELF radio wave scattered by a conducting disturbance, which is likely to take place in the middle atmosphere over Taiwan. Model computations show that the South American thunderstorms (Amazon basin) play the leading role in maintaining radio signals, leading to the anomaly in the Schumann resonance.

Studies on the shift in the frequency of the first Schumann resonance mode during a solar proton event

2010 ◽  
Vol 72 (11-12) ◽  
pp. 829-836 ◽  
Author(s):  
S.S. De ◽  
B.K. De ◽  
B. Bandyopadhyay ◽  
Suman Paul ◽  
D.K. Haldar ◽  
...  
Keyword(s):  
Solar Proton ◽  
Resonance Mode ◽  
Solar Proton Event ◽  
Proton Event ◽  
Schumann Resonance

UNIFICATION OF STANDS SELECTION FOR FINAL FELLING IN STRATEGIC AND TACTICAL PLANNING

2015 ◽  
Author(s):  
Ainārs GRĪNVALDS
Keyword(s):  
Strategic Planning ◽  
Net Present Value ◽  
Strategic Plan ◽  
Regression Function ◽  
Tactical Planning ◽  
Present Value ◽  
Black Alder ◽  
Value Maximization ◽  
Annual Changes ◽  
Selection For

The stand selection for cutting in tactical planning should be done according to the same principles like in strategic planning – to maximize net present value. The simple way of how to transfer the net present value maximization principle from strategic planning to tactical planning was created in Sweden. The method is based on annual changes in the net present value by postponing final felling. Forest inventory data and forestry modelling system was used for calculation of changes in net present value for pine, spruce, birch, aspen and black alder stands. And changes in net present value were described by regression function with factors from stand parameters. The regression function allows calculating annual changes in net present value for each stand. And stands with higher decrease in net present value have higher cutting priority. Stands selected for the final felling in strategic plan were compared with the stands selected in tactical plan with two methods, first, by using annual changes in the net present value, second, by traditional planning principles. Stands selected by annual changes in the net present value were similar to stands that were selected for cutting in strategic plan, but stands selected by traditional planning principles – not.

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