Low Rate Information Transmission

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Low Rate Information Transmission
Product Suite
Charles Vance
charlie.vance_at_noaa.gov
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Americas in Miami, Florida December 9-13, 2002
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L R I T

• Sometimes referred to as
• Digital WEFAX
• High Speed WEFAX
• Next Generation WEFAX
• LRIT is more than WEFAX

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WEFAX (Weather Facsimile) Transmits only images
using low rate facsimile, 24 hours a day on a
fixed schedule of 4 and 5 minute time slots
0100 17Z 72Hr MSLP/1000-500 THK 0105 17Z 72Hr
500MB HT PA33 W502 0110 GOES-8 2345Z NE IR
0114 GOES-8 2345Z SE IR 0118 GOES-8 2345Z NW
IR 0122 GOES-8 2345Z SW IR 0126 GOES-8 2345Z
4KM US IR 0130 GOES-8 2345Z 16KM FD IR 0134
GOES-8 2345Z NH WV 0138 GOES-8 2345Z NE WV
0142 GOES-8 2345Z SE WV 0146 GOES-8 2345Z NH
WV 0150 GOES-8 2345Z SW WV 0154 GOES-8 0045Z
NH IR 0158 GOES-8 2345Z 16KM FD WV
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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!

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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

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Geostationary Satellite Data
Polar Satellite Data
Text and Administrative Messages
L R I T
Integrated Stream of Digital Products

• NWS Data (including)
• Models/Charts
• EMWIN

GOES Data Collection Service
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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

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16 KM Full Disk
4 KM CONUS
IR
WV
IR
VIS
14 WEFAX PRODUCTS FROM 1 DAYTIME FULL DISK
8 KM Northern Hemisphere and Quadrants
IR
IR
VIS
VIS
IR
WV
IR
IR
VIS
VIS
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Americas in Miami, Florida December 9-13, 2002
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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
minutes Slightly longer than normal GVAR
transmission
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Americas in Miami, Florida December 9-13, 2002
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LRIT Viewer Screen Shot GOES-10 8 Km IR
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Americas in Miami, Florida December 9-13, 2002
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LRIT Viewer Screen Shot GOES-10 8 Km IR Missing
Segment w Overlays
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Satellite Direct Readout Conference for the
Americas in Miami, Florida December 9-13, 2002
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LRIT Viewer Screen Shot GOES-10 8 Km IR Missing
Segment w Zoom
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Satellite Direct Readout Conference for the
Americas in Miami, Florida December 9-13, 2002
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LRIT Viewer Screen Shot GOES-8 8 Km IR
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Satellite Direct Readout Conference for the
Americas in Miami, Florida December 9-13, 2002
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LRIT Viewer Screen Shot GOES-8 8 Km IR with Zoom
and Overlay
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Satellite Direct Readout Conference for the
Americas in Miami, Florida December 9-13, 2002
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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

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Satellite Direct Readout Conference for the
Americas in Miami, Florida December 9-13, 2002
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LRIT Viewer Screen Shot (Compressed) GMS with
ZOOM (Embedded Overlays)
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LRIT Receiver Screen Shot
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Satellite Direct Readout Conference for the
Americas in Miami, Florida December 9-13, 2002
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Time Share of WEFAX and LRIT During
Transition
Reduced Product Suite for Each Service
Alternates Each Hour

• LRIT
• GOES
• NWS products
• Models/Charts
• EMWIN
• GMS
• GOES DCS channel?

WEFAX GOES Images NWS Charts GMS Meteosat?
00
05
55
50
10
15
45
40
20
35
25
30
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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

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Satellite Direct Readout Conference for the
Americas in Miami, Florida December 9-13, 2002
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Are you ready?

• Email LRIT_at_NOAA.GOV
• http//www.osdpd.noaa.gov/COB/COB.html
• http//noaasis.noaa.gov/WEFAX/ ( /LRIT/ ? )
• http//www.nws.noaa.gov/datamgmt/doc/lrit.html

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Satellite Direct Readout Conference for the
Americas in Miami, Florida December 9-13, 2002