One of the most attractive features of the Unidata Internet Data Distribution
(IDD) system is the ease with which new and different data products from different
sources can be incorporated. While the raw data are delivered by the IDD in various
digital forms which depend on the data type, graphical depictions of some of the
different types generated at Unidata sites are shown here for purposes of illustration.
For more complete descriptions of the data streams, see
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Weather stations around the world report atmospheric temperature, pressure,
winds, cloud cover, visibility, special weather conditions, and other observations.
These data are collected on a regular basis and made available from the
National Weather Service (NWS) via
the Domestic Data Service(DDS)
and International Data Service (IDS). These are both part of the NWS Family
of Services (FOS). Through
a subcontract with Alden Electronics,
the DDS information is disseminated to universities via the Unidata IDD.
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In addition to the observations of surface and upper air conditions, the
NWS Family of Services contains the output of a variety forecast models
run on supercomputers at the National Centers for Environmental Prediction
(NCEP , formerly known
as the National Meteorological Center ,NMC) and the European Center for
Medium Range Weather Forecasting (ECMWF). These data products are disseminated
on the High Resolution Stream (HRS).
As part of the FOS, these products are also injected into the IDD by Alden
Electronics as part of their contract with Unidata. |
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Unidata has a tailored set of data products prepared at the Space Science
and Engineering Center (SSEC ) at
the University of Wisconsin, Madison. These data are disseminated on what
is called the Unidata/Wisconsin
or McIDAS channel. One special feature of this data stream is satellite
imagery. Most of the images are from Geostationary Orbiting Environmental
Satellites (GOES), but certain data from other satellite observing platforms
can be injected on special request. Currently SSEC is the IDD injection
point for all satellite imagery. |
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Radar Data
Certain manually digitized radar products are delivered with conventional
weather reports as part of the Domestic Data Service, but data from the
new NEXRAD radar systems is only available through commercial providers
who gather the data from the individual NEXRAD sites. Unidata made special
arrangements with WSI Corporation
to give the university community the option of subscribing to the NEXRAD
Information Dissemination Service (NIDS) products via the IDD. More detailed
information on NIDS data can be found in
NEXRAD Information Dissemination Service (NIDS) on the Unidata
WWW server. |
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Lightning Strike Data
Many Unidata universities are interested in lightning data. Unlike other
sources of weather related data, the National Lightning Detection Network
(NLDN) is owned and operated entirely by a private company, Global Atmospherics,
Inc. of Tucson, Arizona. However, the State University of New York at Albany
(SUNYA) has arranged with Global
Atmospherics to deliver data from the NLDN to several interested universities
for education and research purposes. More detailed information on lightning
data can be found in
Lightning Data Available on the Internet on the Unidata WWW server.
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Experimental Data Products
One of the main advantages of the IDD approach is that universities can
use the technology to move data from one site to another without any central
coordination. As one example of this, the University
of Michigan is using LDM/IDD technology to create mirror servers for
the suite of electronic weather maps it generates each hour. This provides
several access points for the many K-12 schools that use the weather maps
in their classrooms. |