From Radar Design Principles: Signal Processing and the Environment, Second Edition

F. E. Nathanson

J. P. Reilly


Meteorological phenomena have two major effects on radar: the signals are attenuated by clouds, rain, snow, and the atmosphere itself; a relatively large signal is reflected from raindrops, hail, and snowflakes. [1] Attenuation becomes quite significant above X-band (9300 MHz), but backscatter from snow and rainfall generally dominates the detection and tracking problem at frequencies down to L-band (1300 MHz). To compound the problem, the backscatter spectrum from precipitation and chaff is broadened because of wind shear, vertical fall rates, and air turbulence, all of which limit the ability of Doppler processors to separate targets from clutter on the basis of their relative velocities. The backscatter coefficient of chaff dipoles is shown to have much less dependence on the carrier frequency than precipitation echoes, but both have similar amplitude and spectral distributions. The equations and numerical values in this chapter apply to monostatic radars with linear polarization.

[1]For general references see NASA Publications [361] [239] Atlas, "Advances in Radar Meteorology" [25], Battan, Radar Meteorology [48], and Doviak and Zrinc [187].

6.1 Standard Atmospheric Attenuation

Atmospheric attenuation has been treated by L. V. Blake and in NASA publications [2391 [361]. Figure 6.1 from Blake shows the normal atmospheric attenuation through the entire troposphere. The attenuation for a horizontal beam at sea level as a function of range and frequency is shown in Fig. 6.2. Numerous other curves are given in the references. The attenuation coefficient per mile at sea level can...

Products & Services
Weather Radar Systems

Weather radar systems, also called weather surveillance radar and Doppler weather radar, is a type of radar used to locate precipitation, determine precipitation type, and calculate its motion.

Weather Instruments
Weather instruments are designed to measure one or multiple components of weather including wind speed and direction, rain or snow fall, solar radiation, temperature, pressure and humidity.
Radomes are weatherproof enclosures to protect an antenna from the elements. Radomes are more typically used on satellite or microwave antennas, but can be used with any antenna.
Crystal Filters
Crystal filters are electronic filters that use monolithic crystals.
Altimeters are instruments used to determine an object’s altitude above ground or sea level by interpreting measurements of atmospheric pressure, radar or GPS signals.

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