Garmin GI 275 Pilot's Manual page 148

Hazard Avoidance
Reflectivity is the amount of transmitted power returned to the radar receiver. Colors on the
NEXRAD display directly correlate to the level of detected reflectivity. Reflectivity as it relates
to hazardous weather can be very complex. The role of radar is essentially to detect moisture
in the atmosphere. Simply put, certain types of weather reflect radar better than others. The
intensity of a radar reflection is not necessarily an indication of the weather hazard level. For
instance, wet hail returns a strong radar reflection, while dry hail does not. Both wet and dry
hail can be extremely hazardous.
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.
Range
Touch to display
Time Stamp
information
S XM neXrAD S
iriuS
Source selection for SiriusXM radar imagery includes the following:
ƒ Composite – Displays composite reflectivity image scanned from multiple elevation
angles
ƒ Base – Displays base reflectivity image scanned from a single elevation angle
126
NEXRAD on weather page
S
OurCe eleCtiOn
Garmin GI 275 Pilot's Guide
NEXRAD
Precipitation
No Radar
Coverage
190-02246-01 Rev. A