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Radar cross-section (RCS), denoted σ, also called radar signature, is a measure of how detectable an object is by radar. A larger RCS indicates that an object is more easily detected. [1] An object reflects a limited amount of radar energy back to the source. The factors that influence this include: [1] the material with which the target is made;
Weather radar in Norman, Oklahoma with rainshaft Weather (WF44) radar dish University of Oklahoma OU-PRIME C-band, polarimetric, weather radar during construction. Weather radar, also called weather surveillance radar (WSR) and Doppler weather radar, is a type of radar used to locate precipitation, calculate its motion, and estimate its type (rain, snow, hail etc.).
Due to the irregular and variable size, shapes, and dielectric constants of debris particles, debris balls typically produce a correlation coefficient (ρ hv) less than 0.80. Differential reflectivity ( Z DR ) values associated with debris balls are typically near or below 0 dB due to the random, tumbling nature of tornadic debris.
Dual-polarized WSR-88D radar image of the 2021 Naperville–Woodridge tornado, showing four products used to detect active tornadoes: high reflectivity returns in dBZ and low correlation coefficient returns, when paired with low differential reflectivity returns, indicate a tornado debris signature, and the strong opposing velocity values form ...
For jointly wide-sense stationary stochastic processes, the definition is = = [() (+) ¯] The normalization is important both because the interpretation of the autocorrelation as a correlation provides a scale-free measure of the strength of statistical dependence, and because the normalization has an effect on the statistical ...
In radar satellites, microwave signals are reflected off a persistent scatter in a target area, and their two-way travel time is measured by satellites. [1] Water vapor in the troposphere and free electrons in the ionosphere affect the propagation of microwave signals through the atmosphere because the different refractive index in these layers affects the speed of propagation.
where , is the amplitude of the electric field scattered by the mth scatterer, is the position of the mth scatterer, is the carrier frequency and , represents the shift in phase of the scattered wave in the direction of the radar due to the relative radial velocity of the target with respect to the radar, while , and are respectively the phase ...
A correlation coefficient is a numerical measure of some type of linear correlation, meaning a statistical relationship between two variables. [ a ] The variables may be two columns of a given data set of observations, often called a sample , or two components of a multivariate random variable with a known distribution .