scholarly journals Characteristics of solar diurnal variations: A case study based on records from the ground magnetic station at Vassouras, Brazil

2013 ◽  
Vol 92 ◽  
pp. 124-136 ◽  
Author(s):  
V. Klausner ◽  
A.R.R. Papa ◽  
O. Mendes ◽  
M.O. Domingues ◽  
P. Frick
Keyword(s):  
Diurnal Variations ◽  
Ground Magnetic ◽  
Magnetic Station

Intense dB/dt variations driven by near-Earth Bursty Bulk Flows (BBFs): A case study

2021 ◽  
Author(s):  
Dong Wei ◽  
Malcolm Dunlop ◽  
Junying Yang ◽  
Xiangcheng Dong ◽  
Yiqun Yu ◽  
...  
Keyword(s):  
Large Scale ◽  
Current System ◽  
Geomagnetically Induced Currents ◽  
Inner Magnetosphere ◽  
Wide Range ◽  
Ground System ◽  
Induced Currents ◽  
Ground Magnetic ◽  
Bursty Bulk Flows

<p>During geomagnetically disturbed times the surface geomagnetic field often changes abruptly, producing geomagnetically induced currents (GICs) in a number of ground based systems. There are, however, few studies reporting GIC effects which are driven directly by bursty bulk flows (BBFs) in the inner magnetosphere. In this study, we investigate the characteristics and responses of the magnetosphere-ionosphere-ground system during the 7 January 2015 storm by using a multi-point approach which combines space-borne measurements and ground magnetic observations. During the event, multiple BBFs are detected in the inner magnetosphere while the magnetic footprints of both magnetospheric and ionospheric satellites map to the same conjugate region surrounded by a group of magnetometer ground stations. It is suggested that the observed, localized substorm currents are caused by the observed magnetospheric BBFs, giving rise to intense geomagnetic perturbations. Our results provide direct evidence that the wide-range of intense dB/dt<strong> </strong>(and dH/dt) variations are associated with a large-scale, substorm current system, driven by multiple BBFs.</p>

scholarly journals Variation of diurnal Turbulence Kinetic Energy using sonic anemometer observation: a case study Ledeng, Bandung

2018 ◽  
Author(s):  
Sandy Hardian Susanto Herho ◽  
Dasapta Erwin Irawan
Keyword(s):  
Kinetic Energy ◽  
Diurnal Variation ◽  
Wind Velocity ◽  
Sonic Anemometer ◽  
Diurnal Variations ◽  
Turbulence Kinetic Energy ◽  
Atmospheric Conditions

Sonic anemometer observation was performed on 29 - 30 September 2014 in Ledeng, Bandung to see diurnal variations of Turbulence Kinetic Energy (TKE) that occurred in this area. The measured sonic anemometer was the wind velocity components u, v, and w. From the observation result, it can be seen that the diurnal variation that happened was quite significant. The maximum TKE occurs during the daytime when atmospheric conditions tend to be unstable. TKE values were small at night when atmospheric conditions are more stable than during the daytime.

Delineating hydrothermal stockwork copper deposits using controlled-source and radio-magnetotelluric methods: A case study from northeast Iran

Geophysics ◽  
2009 ◽  
Vol 74 (5) ◽  
pp. B167-B181 ◽  
Author(s):  
Mehrdad Bastani ◽  
Alireza Malehmir ◽  
Nazli Ismail ◽  
Laust B. Pedersen ◽  
Farhang Hedjazi
Keyword(s):  
Signal To Noise Ratio ◽  
Three Dimensional ◽  
Near Surface ◽  
2D Inversion ◽  
Controlled Source ◽  
Copper Mineralization ◽  
Radio Transmitters ◽  
Ground Magnetic ◽  
2D Resistivity

Radio- and controlled-source-tensor magnetotelluric (RMT and CSTMT) methods are used to target hydrothermal veins of copper mineralization. The data were acquired along six east-west- and three north-south-trending profiles, covering an area of about [Formula: see text]. The tensor RMT data were collected in the [Formula: see text] frequency band. A double horizontal magnetic dipole transmitter in the [Formula: see text] frequency range allowed us to constrain the deeper parts of the resistivity models better. To obtain optimum field parameters, ground magnetic profiling was conducted prior to the RMT and CSTMT surveys. Although the study area (in Iran) is remote, a number of radio transmitters with acceptable signal-to-noise ratio were utilized. The 2D inversion of RMT data led to unstable resistivity models with large datamisfits. Thus, the RMT data were used to complement and analyze the near-surface resistivity anomalies observed in the 2D CSTMT models. Analyses of strike and dimensionality from the CSTMT data suggests that the low-resistivity structures are mainly three dimensional; therefore, 2D inversion of determinant data is chosen. Independent 2D inversion models of the determinant CSTMT data along crossing profiles are in good agreement. Known copper mineralization is imaged well in the CSTMT models. The thinning of the conductive overburden correlates very well with magnetic highs, indicating the bedrock is resistive and magnetic. In this sense, the magnetic and electromagnetic fields complement each other. Analysis of the 2D resistivity models indicates the volcanic rock deepens at the center of the study area. This zone is associated with a magnetic low and therefore is recommended for detailed exploration work.

Diurnal variations of radon and mixing heights along a coast: A case study

1980 ◽  
Vol 85 (C7) ◽  
pp. 4107 ◽  
Author(s):  
S. A. Hsu ◽  
R. E. Larson ◽  
D. J. Bressan
Keyword(s):  
Diurnal Variations

A multi-scale ground and drone-borne magnetic survey approach for the detection and investigation of archaeological structures

2021 ◽  
Author(s):  
Bruno Gavazzi ◽  
Hugo Reiller ◽  
Marc Munschy ◽  
Gilles Pierrevelcin ◽  
Florian Basoge ◽  
...  
Keyword(s):  
Vertical Component ◽  
High Amplitude ◽  
Magnetic Survey ◽  
Rhine River ◽  
Near Surface ◽  
Multi Scale ◽  
Electric Power Line ◽  
Frequency Magnetic Field ◽  
Ground Magnetic

<p><span>Ground magnetic surveys are commonly used for imaging near-surface structures in archaeological studies. Usually, surveys are conducted using vertical component gradiometers or scalar gradiometers to produce a vertical pseudo-gradient map. Scalar magnetometers can also be used, albeit less frequently, to produce maps of the total magnetic anomaly. In all these cases, the equipment is pushed or pulled by an operator or carried behind a vehicle. Here we present a third approach made available by the use of three-component fluxgate magnetometers: fast surveys over large areas using a compact lightweight drone flying automatically 1 to 2 m above the ground and high precision surveys acquired by an operator 0,2 to 1 m above the ground. A case study on the gallo-roman site of Oedenburg, </span><span>located</span><span> along the Rhine River in its upper valley, illustrates the results that can be obtained with the approach. A comparison with previously acquired pseudo-gradient surveys show</span><span>s</span><span> that the presented method allows a faster coverage, a greater resolution for the imaging of short wavelength structures (such as walls) and a better capacity of imaging large wavelength structures (such as pathways, palaeochannels or soil composition variations). As the site is crossed by a high voltage electric power line, a method to suppress the high-amplitude 50 Hz frequency magnetic field is presented.</span></p>

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