Garmin Aera 660 Pilot's Manual page 132

Hazard Avoidance
The radar data displayed is not real-time. The lapsed time between collection,
processing, and dissemination of radar images can be significant and may not reflect
the current radar synopsis. Due to the inherent delays and the relative age of the
data, it should be used for long-range planning purposes only. Never use radar data
to penetrate 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 tilt
angles 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.
Radar Abormalities
There are possible abnormalities regarding displayed radar images. Some, but not
all, of those include:
scans
Radar Limitations
Certain limitations exist regarding radar displays. Some, but not all, are listed for
the user's awareness:
of pink for indeterminate types. The actual precipitation type aloft could vary.
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Garmin aera 660 Pilot's Guide
190-02017-20 Rev. E