Download - L ow R ate I nformation T ransmission
Low Rate Information TransmissionProduct Suite
Satellite Direct Readout Conference for the Americas in Miami, Florida December 9-13, 2002 1
Charles Vance [email protected]
L R I T
Sometimes referred to as:• Digital WEFAX• High Speed WEFAX• Next Generation WEFAX
LRIT is more than WEFAX
Satellite Direct Readout Conference for the Americas in Miami, Florida December 9-13, 2002 2
01:00 17Z 72Hr MSLP/1000-500 THK 01:05 17Z 72Hr 500MB HT PA33 W502 01:10 GOES-8 2345Z NE IR 01:14 GOES-8 2345Z SE IR 01:18 GOES-8 2345Z NW IR 01:22 GOES-8 2345Z SW IR 01:26 GOES-8 2345Z 4KM US IR 01:30 GOES-8 2345Z 16KM FD IR 01:34 GOES-8 2345Z NH WV 01:38 GOES-8 2345Z NE WV 01:42 GOES-8 2345Z SE WV 01:46 GOES-8 2345Z NH WV 01:50 GOES-8 2345Z SW WV 01:54 GOES-8 0045Z NH IR 01:58 GOES-8 2345Z 16KM FD WV
WEFAX(Weather Facsimile)
Transmits only images using low rate facsimile, 24 hours a day on a fixed schedule of 4 and 5
minute time slotsPRODUCTS
GOES EAST GOES WEST
135 GOES 132 GOES
59 NWS Charts 58 NWS Charts
44 NOAA Polar 44 NOAA Polar
2 TBUS 3 msg files 2 TBUS 3 msg files
67 Meteosat 7 Meteosat
40 GMS
Satellite Direct Readout Conference for the Americas in Miami, Florida December 9-13, 2002 3
L R I T(More than WEFAX)
Integrated Stream of Digital Products that can be Transmitted Asynchronously
Improved Image Resolution
Can Utilize Compression
Diverse Product Suite
Digital Text Messages!Satellite Direct Readout Conference for the Americas in Miami, Florida December 9-13, 2002 4
Initial LRIT Product Suite• Used WEFAX as a Baseline and
– Reduced latency– Increased resolution– Improved user flexibility
• Also added other services such as– NWS messages including EMWIN– DCS
• Evolving Capabilities and Products
Satellite Direct Readout Conference for the Americas in Miami, Florida December 9-13, 2002 5
Geostationary Satellite Data Polar Satellite Data
GOES Data Collection Service
NWS Data (including)• Models/Charts• EMWIN
L R I TL R I T Integrated Stream of Digital Products
Text and Administrative Messages
Satellite Direct Readout Conference for the Americas in Miami, Florida December 9-13, 2002 6
GOES Imagery Example WEFAX Limitations
• Resolution Limitations– Pixel Area limited by 2.4KHz modulation– Pixel Depth (brightness) roughly 6.5 bits
• Latency– One Daytime GOES Full Disk Ingest generating
14 WEFAX image products takes 56 minutes to transmit
– Initial processing delays of 25 minutes– Scheduling – images sent one after another
Satellite Direct Readout Conference for the Americas in Miami, Florida December 9-13, 2002 7
14 WEFAX PRODUCTS FROM 1 DAYTIME FULL DISK8 KM Northern Hemisphere and Quadrants
16 KM Full Disk 4 KM CONUS
IR WV IR VIS
IR
WV
IR IR
IR IR
VIS
VISVIS
VIS
Satellite Direct Readout Conference for the Americas in Miami, Florida December 9-13, 2002 8
LRIT Transmits Full Disk in near real time segments for improved reliability and less latency
User can generate sectors for areas of interest
Missing segment does not negate
entire transmission
Total Transmission time of approximately 20-25 minutesSlightly longer than normal GVAR transmission
Satellite Direct Readout Conference for the Americas in Miami, Florida December 9-13, 2002 9
LRIT Viewer Screen ShotGOES-10 8 Km IR
Satellite Direct Readout Conference for the Americas in Miami, Florida December 9-13, 2002 10
LRIT Viewer Screen ShotGOES-10 8 Km IR Missing Segment w Overlays
Satellite Direct Readout Conference for the Americas in Miami, Florida December 9-13, 2002 11
LRIT Viewer Screen ShotGOES-10 8 Km IR Missing Segment w Zoom
Satellite Direct Readout Conference for the Americas in Miami, Florida December 9-13, 2002 12
LRIT Viewer Screen ShotGOES-8 8 Km IR
Satellite Direct Readout Conference for the Americas in Miami, Florida December 9-13, 2002 13
LRIT Viewer Screen ShotGOES-8 8 Km IR with Zoom and Overlay
Satellite Direct Readout Conference for the Americas in Miami, Florida December 9-13, 2002 14
GOES Imagery Example LRIT Improvements
• Resolution– Pixels per line variable and ‘unlimited’– Pixel Depth of 8 bits (generally)
• Latency– Initial processing delays minimized– One Daytime GOES Full Disk Ingest sent in
segments taking 20 – 25 minutes to transmit– Scheduling – multiple products sent
‘simultaneously’
Satellite Direct Readout Conference for the Americas in Miami, Florida December 9-13, 2002 15
LRIT Viewer Screen Shot(Compressed) GMS with ZOOM (Embedded Overlays)
Satellite Direct Readout Conference for the Americas in Miami, Florida December 9-13, 2002 16
LRIT Receiver Screen Shot
Satellite Direct Readout Conference for the Americas in Miami, Florida December 9-13, 2002 17
Time Share of WEFAX and LRIT During Transition
0500
30
50
154540
5510
202535
Reduced Product Suite for Each ServiceAlternates Each
HourWEFAX
GOES Images
NWS Charts
GMS
Meteosat?
LRIT
GOES
NWS products• Models/Charts• EMWIN
GMS
GOES DCS channel?Satellite Direct Readout Conference for the Americas in Miami, Florida December 9-13, 2002 18
Summery
• LRIT is an Integrated Stream of Diverse Digital Products that can be Transmitted Asynchronously and has Reduced Latency, Improved User Flexibility, Increased Resolution, and Increased Reliability compared to WEFAX
• The LRIT Product Suite is User Driven
Satellite Direct Readout Conference for the Americas in Miami, Florida December 9-13, 2002 19
Are you ready?
• Email: [email protected]
• http://www.osdpd.noaa.gov/COB/COB.html
• http://noaasis.noaa.gov/WEFAX/ ( /LRIT/ ? )
• http://www.nws.noaa.gov/datamgmt/doc/lrit.html
Satellite Direct Readout Conference for the Americas in Miami, Florida December 9-13, 2002 20