L ow R ate I nformation T ransmission Product Suite Satellite Direct Readout Conference for the Americas in Miami, Florida December 9-13, 2002 1 Charles.

Low Rate Information Transmission

Product 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 slots

PRODUCTS

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

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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

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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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14 WEFAX PRODUCTS FROM 1 DAYTIME FULL DISK

8 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

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LRIT Viewer Screen ShotGOES-10 8 Km IR

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LRIT Viewer Screen ShotGOES-10 8 Km IR Missing Segment w Overlays

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LRIT Viewer Screen ShotGOES-10 8 Km IR Missing Segment w Zoom

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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

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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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LRIT Viewer Screen Shot(Compressed) GMS with ZOOM (Embedded Overlays)

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LRIT Receiver Screen Shot

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Time Share of WEFAX and LRIT During Transition

0500

30

50

1545

40

55

10

202535

Reduced Product Suite for Each Service

Alternates Each Hour

WEFAX

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

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