Duct Simulation Analysis And Three-dimensional Interpolation Of Radar Data Processing

The speed of a radio wave in the atmosphere is determined by the dielectric property of the air. This property depends on the pressure, temperature and humidity of the air. In general as we move upwards through the atmosphere the pressure decreases and temperature falls. This means that the dielectric property changes with height and allows a slight increase in the speed of a radio wave as we move upwards through the atmosphere. This in turn means that if a radio wave moves away from the earth at an angle less than 90 degrees, then the upper part of the wave travels faster than the lower part. Therefore even under normal conditions this can in effect bend, or refract, the wave back down to earth.Tropospheric ducting occurs when we get a sharp rate of change in the dielectric constant as we move upwards through the atmosphere. This occurs when we get a rapid increase of temperature and a rapid decrease in humidity (dew-point) with height.In terms of deriving the maximum trapped-wavelength and the critical emitting angle of elevation for electromagnetic wave which can forms duct propagation and introducing the four kinds necessary condition for electromagnetic wave to form duct propagation, Under these conditions we now have the radio wave bent back towards the earth. However, the radio wave can then reflect back of the earth and become refracted again to return earthwards once more. This can sometimes occur a number of times with little attenuation but some fading. The result can be long distance reception of radio waves that would normally have been far beyond the radio horizon.The equations for ray tracing were given, simulating and tracing electro-magnetic wave duct propagation using spherical layered atmosphere mode, This method is very useful for analysis of radar echo distribution and confirm relation of stratification of atmosphere and ray duct propagationIn the process of studying radar second product, introduce a new 3-D interpolation method. Outcome of this method can suit all kinds of density product. And use some of the products to test its feasibility. On the base of the method, studied the 2-D isoline of the echo top etc and carry it out with Visual C++.