An Investigation of the Requirements of an Airborne, Scanning Polarimetric Phased Array Radar to Accurately Measure Hydrometeor Properties Near the Earth's Surface

Accurately measuring the properties of weak weather echoes in the presence of strong ground clutter is a challenge for any ground-based scanning radar, but it is particularly difficult for scanning airborne radar whose beam routinely and directly intercepts the ground. If one further considers phased array radar which requires the use of pulse compression to compensate for the lack of available peak transmit power, the influence of the ability to accurately measure the properties of weather echoes near the surface is exasperated not only by the antenna sidelobes, but also by range time sidelobes which are a side-effect of pulse compression. Normalized radar cross section (NRCS) of the Earth’s surface has been characterized for land and water at various radar frequencies and grazing angles. NRCS data at C-band, will be examined in order to establish realistic expectations and requirements for Airborne Phased Array Radar (APAR) (Vivekanandan et al. 2014) for discerning weak weather echoes near the Earth’s surface. The methodology used can be applied to analyze the requirements of other airborne scanning radars.

References

Vivekanandan, J., W.-C. Lee, E. Loew, J. L. Salazar, V. Grubišić., J. Moore, and P.Tsai, 2014: The next generation airborne polarimetric Dopler weather radar. Geosci. Instrum. Method. Data Syst. Journal, 3, 111-126. doi:10.5194/gi-3-111-2014, 2014.