pheric radio noise given in CCIR Report were obtained by aleast squares fit to the CCIR Report curves representing upper decile (Du) and lower. Geographic and frequency dependent distributions of atmospheric noise *power enumerated in CCIR Report () are approximated by series. Download Citation on ResearchGate | CCIR Report Noise Variation Parameters | Naval Command Control and Ocean Surveillance Center, RDT&E Division.
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Atmospheric noise is radio noise caused by natural atmospheric processes, primarily lightning discharges in thunderstorms. Karl Janskya year-old researcher, undertook the task. Bya radio antenna for a wavelength of Jansky recognized three sources of radio noise.
Catalog Record: A numerical representation of CCIR report | Hathi Trust Digital Library
The second source was weaker noise from more distant thunderstorms. The third source was a still weaker hiss that turned out to be galactic noise rpeort the center of the Milky Way.
Jansky’s research made him the father of radio astronomy. It is mainly caused by cloud-to-ground flashes as the current is much stronger than that of cloud-to-cloud flashes. This is about 40 lightning flashes per second. The sum of all these lightning flashes results in atmospheric noise. It can be observed,  with a radio receiver, in the form of a combination of white noise coming from distant thunderstorms and impulse noise coming from a near thunderstorm.
The power-sum varies with seasons and nearness of thunderstorm centers. Although lightning has a broad-spectrum emission, its noise power increases with decreasing frequency. Therefore, at very low frequency and low frequencyatmospheric noise often dominates, while at high frequencyman-made noise dominates in urban areas.
From s to s, a worldwide effort was made to measure the atmospheric noise and variations. Atmospheric noise and variation is also used to generate high quality random numbers.
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Science On a Sphere. Retrieved 15 May Archived from the original on Noise physics and telecommunications. Channel noise level Circuit noise level Effective input noise temperature Equivalent noise resistance Equivalent cdir code modulation noise Impulse noise audio Noise figure Noise floor Noise shaping Noise spectral density Noise, vibration, and harshness NVH Phase noise Pseudorandom noise Statistical noise.
List of noise topics Acoustics Colors of noise Interference communication Noise generator Radio noise source Spectrum analyzer Thermal radiation.
General Low-pass filter Median filter Total variation denoising Wavelet denoising.