NOUS41 KWBC 281050 AAA



Technical Implementation Notice 12-45, Amended

National Weather Service Headquarters Washington DC

650 AM EDT Fri Sep 28 2012


To:       Subscribers:

          -Family of Services

          -NOAA Weather Wire Service

          -Emergency Managers Weather Information Network


          Other NWS Partners, Users and Employees


From:     Timothy McClung

          Chief, Science Plans Branch

          Office of Science and Technology


Subject:  Amended Date: Addition of Alaska Region NPP VIIRS

          Imagery to NOAAPORT Test Channel Effective

          October 10, 2012


Amended to reschedule the implementation to Wednesday, October

10, 2012, to allow for additional testing.


On or about Wednesday, October 10, 2012, beginning approximately

1500 Coordinated Universal Time (UTC), high resolution imagery

from the Suomi National Polar-Orbiting Partnership (NPP)

satellite will be broadcast across the NOAAPORT satellite

broadcast network. This addition will consist of a limited set of

NPP Visible Infrared Imaging Radiometer Suite (VIIRS) imagery

covering the Alaska region. The imagery stream will be provided

by the NOAA National Environmental Satellite, Data, and

Information Service (NESDIS) NPP Data Exploitation (NDE) system,

based on NPP VIIRS imagery Environmental Data Records (EDRs).


The new NPP VIIRS imagery products will be transmitted across a

test channel of the NOAAPORT satellite broadcast network.


-Digital Video Broadcast (DVB) packet identifier: 105

-Multicast address:

-Port number: 1205

-SBN Data Stream field setting in their frame-level headers: 7


NWS anticipates this NOAAPORT channel will be populated with

additional polar-orbiting satellite imagery. For clarity, this

channel will be referred to as the POLARSAT.


The Alaska region NPP VIIRS imagery will, in general, be within

the following latitude-longitude box:


Lower/Southern Latitude:  45 degrees North

Upper/Northern Latitude:  75 degrees North

Left/Western Longitude:  120 degrees East

Right/Eastern Longitude: 120 degrees West


This initial set of imagery products will be based on three NPP

VIIRS I channels, the horizontal resolution of which, at nadir,

is approximately 375 meters.


The imagery products will be formatted in netCDF4, but compressed

via gzip. Like all NOAAPORT products, each file will have a plain

text WMO heading at its start. These headings are listed below.


TIPB01 KNES - Imagery Channel 1 (0.64um)

TIPB04 KNES - Imagery Channel 4 (3.74um)

TIPB05 KNES - Imagery Channel 5 (11.45um)


The "P" in the third character place of the WMO Heading

distinguishes this NPP-VIIRS imagery from pre-existing NOAAPORT

satellite imagery.


To access these products, users should take the following steps:


-Read beyond or strip off the WMO heading

-Decompress the resulting product, e.g., via gunzip

-Use a netCDF4 reader, e.g., a decoder that invokes the Unidata

netCDF4 software package


Each product will consist of one granule of VIIRS imagery for a

single channel. The VIIRS granules will cover approximately 86

seconds of data, roughly 5 degrees or 556 kilometers of along-

track geographical extent.


Unlike existing NOAAPORT satellite imagery, formatted on

prescribed maps, each NPP VIIRS imagery granule will be uniquely

located. Geolocation information is contained in each product

file. The geolocation information consists of three 1541-

dimension arrays of latitude/longitude pairs that correspond to

the granule edge (first column), granule centerline, and granule

edge (last column), with all three arrays oriented along the

satellite track.


Given the fixed resolution and gridded Ground Track Mercator

representation of the VIIRS imagery, only these three columns of

geographical information (latitudes and longitudes) are required

to map the imagery. This reduced geolocation information can be

interpreted based on the VIIRS Ground Track Mercator imagery

algorithm (fine 375 meter resolution version) for accurate

georeferencing. Related information (though not specific to the

NOAAPORT stream of NPP VIIRS imagery) can be found in the

following document: "Joint Polar Satellite System (JPSS)

Operational Algorithm Description (OAD) Document for VIIRS Ground

Track Mercator (GTM) Imagery Environmental Data Record (EDR)

Software," Revision A, January 18, 2012, (e.g., section 2.0.4).


The NOAAPORT feed of NPP VIIRS imagery is provided across a test

channel of the satellite broadcast network. This NOAAPORT channel

is under test and evaluation.  Product availability across this

channel is nonetheless expected to approach or meet that of

operational/baseline data (i.e., greater than 95% data

availability). If the experimental period is successful, NWS

intends to transition this NOAAPORT stream to full operational

posture in early 2013.


For questions regarding the scientific or technical content of

the NOAAPORT NPP VIIRS imagery feed please contact:


     ESPC Help Desk

     Suitland, Maryland 20746

     Phone: 301-817-3880



For questions regarding the NOAAPORT activation or distribution

of these data sets please contact:


     Brian Gockel

     NOAA/NWS Office of Science and Technology

     Phone: 301-713-0304 x158



NWS Technical Implementation Notices are online at: