Tilt Angle and Ground Clutter

One of the biggest challenges in operating weather radar is learning to distinguish between ground clutter and significant weather. Contrary to popular belief, some ground clutter showing on the radar image is desirable for normal observation. This affirms that the system is functioning and that the beam energy is scanning the air mass above the clutter. Some clutter should appear in the outer portion of the display when at range settings up to 80 NM. Beyond that range, ground clutter will appear progressively closer to the lower part of the display. This is due to the angle of incidence, curvature of the Earth, and distance attenuation of the radar energy.

KEY POINT: Using weather radar on every flight helps you to develop proficiency in picking out ground clutter from precipitation returns.

As Figure 3 shows, ground clutter returns over land will necessitate more upwards adjustment of the tilt angle to compensate for ground clutter than when over water. Bodies of water scatter radar energy forward and away from the radar antenna, producing less clutter, which allows you to have a lower tilt angle set than when over land.

Continue to the next subject.

Return to the TABLE OF CONTENTS .