The two main types of scans used in meteorology are the Plan Position Indicator (PPI) and the Range Height Indicator (RHI) scans.

Plan Position Indicator (PPI): When scanning in PPI mode, the radar holds its elevation angle constant but varies its azimuth angle. The returns can then be mapped on a horizontal plane. If the radar rotates through 360 degrees, the scan is called a "surveillance scan". If the radar rotates through less than 360 degrees, the scan is called a "sector scan".

Range Height Indicator (RHI): When scanning in RHI mode, the radar holds its azimuth angle constant but varies its elevation angle. The returns can then be mapped on a vertical plane. The elevation angle normally is rotated from near the horizon to near the zenith (the point in the sky directly overhead).

target location

Terms for using data resources. CD-ROM available. Credits and Acknowledgments for WW2010. Department of Atmospheric Sciences (DAS) at the University of Illinois at Urbana-Champaign.

radial velocity