Tropospheric Refraction

Refractivity Profile Estimation

As the atmospheric conditions, expressed in terms of radio refractivity, can considerably influence the performance of radio communication links and radar systems, there is a need for reliable prediction of refractivity structure in the lower atmosphere. The usual methods of direct refractive index measurement by means of radiosounding and refractometers can usually only give a rough idea of the refractivity distribution. The basic disadvantage of the radiosonde, resulting from its occasional, although regular, launching, is that it is not able to provide a detailed idea of refractivity structure time development. In recent years, matched field processing methods representing indirect methods of refractivity structure sounding have turned out to be suitable alternative to direct means of measurement.

These methods have been used in the electromagnetic domain to estimate the refractivity structure in the troposphere. In tropospheric propagation, measurement values at a vertical receiver array are usually compared with values obtained by simulation with various refractivity profiles as an environmental parameter. The refractivity estimation is determined by the parameter that gives the best fit between the measurement and the simulation. Similar estimation techniques exist relying on fitting simulation results and measurement data from radar.


Propagation in a Laterally Inhomogeneous Atmosphere

Although the assumption of a horizontally homogeneous atmosphere is justifiable in most cases, situations can occur where the horizontal variability of the atmosphere is of some importance.

New Implementation Techniques ror Ray-Tracing and Parabolic Equation

  • Analytic ray-tracing
  • Domain decomposition for the split-step parabolic equation

Supported by

  • Basic Research of Radiometeorology Properties of Tropospheric Ducting Layers by Using Artificial Intelligence Methods, Czech Science Foundation, grant no. P102/10/1901, 2010-2012
  • Research on Electromagnetic Wave Refraction and Refractivity Height Profiles in Troposphere, Czech Science Foundation, grant no. GA102/07/0955, 2007-2009


Selected papers