Experimental verification of asymmetrical short-term scintillation distribution model

The theory that tropospheric scintillation is associated with turbulence in clouds leads to an asymmetrical distribution of signal level fluctuations in decibels, in contrast to the commonly used symmetrical model. The asymmetry of measured signal fluctuations from Spino d'Adda is evaluated and it is found that the measured short-term distribution is in good agreement with the asymmetrical mode

Asymmetric signal leven distribution due to tropospheric scintillation

Short term distribution of signal fluctions due to tropospheric scintillation (in decibels) is usually modelled as Gaussian. For long term distribution, this results in a symmetrical distribution function. However, various experiments have shown a significant asymmetry in long term distribution for strong scintillations. It is shown that the observed asymmetry follows directly from theory, if a different modelling approach is applied

Statistical analysis of rain fade slope

An analysis is made of the measured distributions of the fade slope of rain attenuation, conditional for attenuation values, measured at Eindhoven University of Technology from the satellite Olympus. It is found that the distribution is similar for positive and negative fade slopes and independent of frequency in the range from 12 to 30 GHz. A distribution model for the conditional distribution is found. The only parameter of the distribution is the standard deviation, which is found to be proportional to attenuation level and dependent on rain type, on the low-pass filter bandwidth and on the time interval used in the slope calculation. The observed relation between the standard deviation and attenuation is compared with results from other measurement sites. From this comparison it is found that the fade slope standard deviation is likely to depend on elevation angle and on climate, through its dependence on rain type

Separation of simultaneous rain and ice depolarization

In the case of depolarization due to rain or to ice crystals, the differential attenuation, the differential phase shift, and the canting angle of the depolarizing medium can all be calculated independently from dual polarized measurement results. However, this is not possible when rain and ice are causing depolarization at the same time. This paper presents a calculation method which makes it possible to derive during simultaneous rain and ice depolarization some of the characterising parameters of each part separately. The method makes use of an a priori known relation between the differential attenuation and the differential phase shift of rain and of ice. The calculation method is tested on measured depolarization events, and yields good results

Asymmetric signal leven distribution due to tropospheric scintillation

Short term distribution of signal fluctions due to tropospheric scintillation (in decibels) is usually modelled as Gaussian. For long term distribution, this results in a symmetrical distribution function. However, various experiments have shown a significant asymmetry in long term distribution for strong scintillations. It is shown that the observed asymmetry follows directly from theory, if a different modelling approach is applied