Garmin G900X Pilot's Manual page 359

Displaying NEXRAD weather information:
1) Press the MAP Softkey (for the PFD Inset Map, press the INSET Softkey). This step is not necessary on the
Weather Data Link (XM) Page.
2) Press the NEXRAD Softkey.
The weather product displays composite information from all the NEXRAD radar sites in the United States.
This information is composed of the maximum reflectivity from the individual radar sweeps. The display
of the information is color-coded to indicate the weather severity level. All weather product legends can be
viewed on the Weather Data Link (XM) Page. For the NEXRAD legend (Figure 6-11), press the LEGEND
Softkey when NEXRAD is enabled for display.
The display of no radar coverage is always active when either NEXRAD or Echo Tops is selected. Areas
where NEXRAD radar coverage and Echo Tops information is not currently available or is not being collected
are indicated in a gray shade of purple (Figure 6-11).
R
eflectivity
Reflectivity is the amount of transmitted power returned to the radar receiver. Colors on the NEXRAD
display are directly correlative 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.
The different NEXRAD echo intensities are measured in decibels (dB) relative to reflectivity (Z). NEXRAD
measures the radar reflectivity ratio, or the energy reflected
letter Z). The value of Z increases as the returned signal strength increases.
190-00726-00 Rev. J
Figure 6-11 NEXRAD Data with Legend
Garmin G900X Pilot's Guide
HAZARD AVOIDANCE
No Radar Coverage
back to
the radar receiver (designated by the
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