[G450 AOM, §2A-05-80 ¶3.] XM Weather (XM WX) is a streaming weather commercial data source which provides selected weather data to the avionics system. XMWeather data is displayed on the 2/3 lateral map display. XMWeather data is broadcast as uplink weather streaming data using the XM network. The data is received at the aircraft using an XMreceiver. The data received is a delayed view of weather conditions. The primary pilot interface for XM Weather is the XM Uplink Weather pull down menu. When XM is installed and enabled in the APM, selecting Up Wx on the map control bar displays the XM Uplink Weather drop down menu.
XM Weather Sources
[www.xmwxweather.com/aviation/] Available instantly and continuously broadcast, the XM WX data stream includes these data products, and many more:
- High-Resolution NEXRAD Radar
- Satellite Imagery
- Winds Aloft
- Freezing Level
Featuring a total of 19 data products for aviation, XM WX Satellite Weather provides a comprehensive data suite for a more complete picture of the weather, at any altitude.
[http://www.crh.noaa.gov/] The National Weather Service's (NWS) Weather Surveillance Doppler Radar (WSR-88D) is a highly sensitive, powerful, and invaluable technology. Key components of the system include the Radar Data Acquisition (RDA) and the Radar Products Generator (RPG) which generate a multitude of radar data for display on the Advanced Weather Interactive Processing System (AWIPS) workstations. The WSR-88D shows the location, intensity, and movement of precipitation, ranging from light snow flurries to very heavy rain and large hail. From the movement of precipitation, the WSR-88D also can sense motion (i.e., velocity) in the atmosphere directed toward and away from the radar (the Doppler effect). Velocity data helps in assessing atmospheric wind fields, as well as severe weather velocity signatures from thunderstorms. The WSR-88D system contains various software algorithms as well that produce a number of other radar products and alarms when threshold values of certain parameters are met. Data from numerous neighboring WSR-88D systems can be ingested and displayed on AWIPS to assist in assessing more distant precipitation systems, including thunderstorms.
[Business Aviation Insider, May/June 2013] NEXRAD uses a ground-based network of 159 Doppler radar stations located throughout the United States. These stations measure several parameters, including cloud development and movement, precipitation type and intensity, and lightning activity. Depending on prevailing weather conditions, a NEXRAD radar station my gather single, three-dimensional image every four minutes during an active storm, or as infrequently as once every 10 to 15 minutes during clear conditions.
The timestamp shown on a NEXRAD display underestimates the age of the information shown. Parts of the image may be three to four minutes old, or more, before the information is transmitted to the pilot. There is no easy way to tell what came from the early part of the sweep and what's from the latest. The NTWB notes that in some extreme cases, the delay could exceed 15 to 20 minutes.
Due to latency, a cell may have advanced five miles from the position noted on the NEXRAD display, though two miles of movement is more typical.
XM Weather is installed on a G450, for example, using ASC 060. The install cost in 2010 was around $56,000. The annual subscription has been running around $600 per year.
Gulfstream G450 Aircraft Operating Manual, Revision 35, April 30, 2013.