Garmin aera 560, Pilot'S Manual

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Garmin aera 500 Series Pilot’s Guide 190-01117-02 Rev. C
82
Hazard Avoidance
Overview
GPS Navigation
Flight Planning
Hazar
d A
voidance
Additional F
eatur
es
Appendices
Index
neXrAD l
IMItAtIonS
Certain limitations exist regarding the NEXRAD radar displays. Some, but not all, are
listed for the user’s awareness:
• NEXRAD base reflectivity does not provide sufficient information to determine
cloud layers or precipitation characteristics (hail vs. rain). For example, it is not
possible to distinguish between wet snow, wet hail, and rain.
• NEXRAD base reflectivity is sampled at the minimum antenna elevation angle. An
individual NEXRAD site cannot depict high altitude storms at close ranges, and
has no information about storms directly over the site.
• Radar coverage only extends to 55°N.
• Any precipitation displayed between 52°N and 55°N is unknown.
neXrAD I
ntenSIty
Colors are used to identify the different NEXRAD echo intensities (reflectivity)
measured in dBZ (decibels of 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 Data RADAR Legend
SATELLITE MOSAIC
Satellite Mosaic displays infrared composite images of cloud cover taken by
geostationary weather satellites. The Satellite Mosaic provides up to seven levels of
cloud cover.