Method of inversing atmospheric duct by radar echo through LPSO algorithm

Abstract

The invention discloses a method of inversing atmospheric duct by radar echo through an LPSO algorithm; the method includes steps of 1), building up air refractive index outline parameterization by using a five-parameter experience model mentioned by Gerstoft or offshore air environment; 2), calculating the radar echo power Pc; according to low incidence angle of the radar, forming a linear function relationship with the propagation distance of a radar electromagnetic wave; 4) based on a propagation model of a parabolic equation (PE), writing the radar electromagnetic wave propagation as an initial side value problem; 5), making 'Fourier conversion' and ' Fourier inverse transformation' of above formula, and acquiring the solution; 6) defining the ratio of the actual field intensity at one point of the space and by using the directional diagram propagation factor F and the field intensity of the same one emitting antenna at the same distance point in the free space along the maximum emitting direction of the antenna; 7), at last, calculating the single-way propagation loss value L at the propagation path (x, z) by the formula below; combining with the real air refractive index outline and the radar system parameter, and calculating the radar echo power by a forward modeling model; 8) establishing a target function by using the actual measured radar echo power and the simulated radar echo power; using the established target function, and inversing the atmospheric duct parameter by LPSO algorithm.

Description

technical field [0001] The invention relates to the fields of atmospheric science and meteorological radar, in particular to a method for inverting an atmospheric waveguide from radar echoes using an LPSO algorithm. Background technique [0002] Under certain meteorological conditions, the electromagnetic wave propagating in the atmospheric boundary layer, especially in the near-surface layer, is affected by the refraction of the atmosphere, and its propagation trajectory is bent to the ground. When the curvature exceeds the curvature of the earth's surface, the electromagnetic wave will be partially trapped in the In a thin layer of atmosphere with a certain thickness, just like electromagnetic waves propagate in a metal waveguide, this phenomenon is called atmospheric duct propagation, and the thin layer of atmosphere forming a waveguide is called an atmospheric duct (Atmospheric duct). [0003] When the atmospheric waveguide appears in the atmospheric environment, the atm...

AI Technical Summary

Problems solved by technology

[0004] Although many achievements have been made in the research of RFC (Refractivity-from-clutter) inversion at home and abroad in recent years, due to the complexity of the problem, the research on RFC is not over, and there are still many problems that need to be further explored. , the most important issues are the parameterization of the waveguide refractive index profile and how to improve the search efficiency in the multi-dimensional parameter space. Various soft and hard constraints are introduced in the inversion to improve the inversion accuracy, such as radar with multiple elevation angles The echo data on the PPI echo map, the regular echo enhancement distance interval in the PPI echo map, and other mesoscale model data, etc.

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