METEOROLOGIST JEFF HABY
Attenuation is the weakening of a radar beam as it moves
downstream due to some of the energy being lost to scattering
and absorption. The further a radar beam moves downstream the more dust, hydrometeors, etc. the radar beam will have
to pass through. Because of attenuation, storms close to the radar are better sampled than storms far from the radar
site. Beam spreading and attenuation both combine to produce a much poorer sampling of storms far from the radar.
Attenuation is higher when the radar beam has the flow through a large number of hydrometeors. Storms and
precipitation close to the radar degrade the radar energy before it reaches storms further from the radar.
Smaller wavelength radar beams attenuate more rapidly than long wavelength radar. Because of this, most
television station radars (C-band) have a shorter range of high clarity compared to the
WSR-88D radar (S-band).