Aspen Avionics Evolution 1000 Pro/VFR PFD, Руководство пилота, Страница: 39 / 66

CHAPTER 4
ASPEN ADS
-B IN
ADS-B Pilot’s Guide
Page 4-13
091-00057-001 REV A
There are two forms of NEXRAD, CONUS and Regional. CONUS NEXRAD is a summary
composite of available NEXRAD radar imagery across the 48 states and is updated every
15 minutes. Regional NEXRAD is a composite of available NEXRAD imagery in a local
area up to 200 nm and shows a more detailed image than the CONUS NEXRAD.
Each NEXRAD radar site has a maximum range of 250 nm. Since NEXRAD data is
not real-time, data is updated from 5 - 15 minutes not including processing and
dissemination time, it should be used for long range planning only. Do not use NEXRAD
to penetrate severe weather. NEXRAD has some limitations including:
• Although reflectivity echoes are possible up to 248 nm, the interpretation of
the data doesn’t work beyond 186 nm, beyond which only the general shape of
storms can be made out.
• The inability to differentiate between types of precipitation, e.g. hail versus
heavy rain.
• Since the radar beam is oriented five degrees above the horizon, the farther
from the antenna, the higher the area scanned by the beam. This translates to
limited low storm detection farther from individual radar locations (i.e. tornados),
and conversely, limited high altitude storm detection directly above the radar
location.