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Environmental Ionizing Radiation
Published in Lorris G. Cockerham, Barbara S. Shane, Basic Environmental Toxicology, 2019
Lorris G. Cockerham, Michael B. Cockerham
Cosmic radiation originates predominately from galactic sources and consists mostly of high-energy protons and alpha particles (BEIR III, 1980; Mettler and Moseley, 1985; Robertson, 1989). At the earth surface, cosmic radiation varies with altitude, geomagnetic latitude, and solar modulation (Hobbs and McClellan, 1986; Fry, 1987). For instance, in the U.S., 48% of the population lives at sea level to 152.5 m and receives a dose rate of about 27 mrem/yr (0.27 µSv/yr), while in Leadville, Colorado (altitude 3200 m), the residents receive about 125 mrem/year.
Errors and Accuracy Issues
Published in Basudeb Bhatta, Global Navigation Satellite Systems, 2021
The ionosphere is not homogeneous. It changes from layer to layer within a particular area, and its behaviour in one region of the earth is liable to be unlike its behaviour in another. For example, ionospheric disturbances are generally high in the polar regions. But the highest TEC values and the widest variations in the horizontal gradients occur in the band of about 60° of geomagnetic latitude. That band lies 30° north and 30° south of the earth’s magnetic equator.
Biological Effects of Static Magnetic Fields
Published in Charles Polk, Elliot Postow, CRC Handbook of Biological Effects of Electromagnetic Fields, 2019
The predominance of north seeking bacteria in the Northern Hemisphere is due to the inclination of the geomagnetic field.175 Since many sediment-dwelling bacteria are anaerobic or microaerobic,* it is advantageous for them to have mechanisms that prevent them from swimining up toward the toxic, higher oxygen concentration at the water surface, and keep them in the sediments. Since the geomagnetic field is approximately dipolar, the magnetic field lines at the surface of the earth are inclined at an angle that increases with latitude. The total flux density at geomagnetic latitude θ is approximately BG=0.3(sin2θ+1)1/2×10−4T and the inclination I from the horizontal is given by tanI=2tanθ In the Northern Hemisphere the field is inclined downwards, pointing straight down at the north magnetic pole. In the Southern Hemisphere the field is inclined upwards, at an angle increasing with latitude, pointing straight up at the south magnetic pole. At the geomagnetic equator the field is horizontal.
Ionospheric delay estimation of Loran skywave using simple cosine model
Published in Electromagnetics, 2023
Kai Zhang, Fan Yang, WeiDong Wang, Chen Zheng, Borong Zou, Hui Li
The magnetic north pole is the point on the earth’s surface where the magnetic field is straight down. Unlike the geographic north pole, it moves over time. The total number of electrons in the ionosphere is usually related to the geomagnetic coordinates, so it is necessary to convert the geographical reflection point coordinates to geomagnetic reflection point coordinates. Assuming that the earth’s magnetic field can be represented by a dipole centered on the earth, geomagnetic latitude can be expressed as (3).