Nexrad Abnormalities - Garmin Pilot User Manual

to maneuver in or near areas of hazardous weather. Rather, use it in an early-warning
capacity for pre-departure evaluation.
Composite data from radar sites in the United States is shown. This data is composed
of the maximum reflectivity from the individual radar sweeps at different title angels
of the radar beam with respect to the ground. The display of the information is color-
coded to indicate the weather severity level. Colors are used to identify the different
echo intensities (reflectivity) measured in dBZ (decibels or Z). "Reflectivity" (designated
by the letter Z) is the amount of transmitted power returned to the radar receiver. The
dBZ values increase as returned signal strength increases. Precipitation intensity is
displayed using colors corresponding to the dBZ values.

NEXRAD Abnormalities

There are possible abnormalities regarding displayed NEXRAD images. Some, but
not all, of those include:
• Ground clutter
• Strobes and spurious radar data
• Sun strobes, when the radar antenna points directly at the sun
• Military aircraft deploy metallic dust (chaff) which can cause alterations in radar
scans
• Interference from buildings or mountains, which may cause shadows
• Poor reception from Ground Based Transceivers (GBTs) can cause portions of the
received radar imagery to not be displayed
190-01501-00 Rev. C Garmin Pilot for iOS User's Guide
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