Does ground clutter look different to a phased array?

Because of the increasing use of phased array antennas for weather observations, it is a good time to revisit the characterization of ground clutter signals for these possibly stationary antennas. Rotating antennas increase the spectrum width of clutter signals because of the changing clutter field illuminated by the antenna beam. Stationary phased array antennas look at the same clutter field over the whole dwell when using electronic scanning. This leads to narrower spectrum widths, but it also leads to different spectral shapes for the clutter signals. To better characterize ground clutter signatures for stationary antennas, a new ground clutter model is introduced that also allows researchers to look for novel ways to mitigate ground clutter on phased arrays. This two-part model improves on earlier clutter models and better captures the true decorrelation time of the clutter. Time series data from the National Weather Radar Testbed phased array antenna are used to characterize ground clutter signals for different wind conditions, foliage levels, and terrain types.