West Coast/Alaska Tsunami
Warning Center
Operations Manual
NOAA/NWS/WCATWC
Palmer,
Section
2.4: Sea Level Network Description
Last Updated:
10/2011
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Both coastal
and deep ocean sea level data are recorded at the WCATWC.
In total, over 1000 channels of signal from about
500 different gages are recorded.
Overall sea level data flow is depicted in Section 3.3.
The majority
of coastal sea level data recorded at the WCATWC are transmitted in near real-time
via the GOES or GMS satellites, through NESDIS/NWS telecommunications gateway,
and back to WCATWC via NWS Telecommunications Lines 276 (the WC/ATWC ARH link
and dedicated comms from ARH to NWSTG) and 277 (public internet from Palmer to
NWSTG). These sea level gages are
operated by many organizations; such as National Ocean Service (NOS), the
Pacific Tsunami Warning Center (PTWC),
A network of 39
deep-ocean tsunami recorders operated by the National Data Buoy Center (32 in
the Pacific and 7 in the Atlantic), or DART buoys, transmit data via the Iridium
satellite phone system to the warning centers.
In addition to these, Chile operates 1 DART off its shore, Australia
operates several off its shores, and two are located west of Indonesia and
Thailand in the Indian Ocean (operated by those two countries).
WCATWC operates coastal gages
at Shemya, Akutan, Old Harbor, Chignik, Middleton
Island, and Craig, Alaska to supplement the NOS
network. A seventh site is maintained in
collaboration with the Alaska Volcano Observatory at Amchitka, Alaska.
The WCATWC network data are recorded in
real-time through the VSAT seismic network data communications system and provided
to the PTWC.
These data can be viewed and is publicly
available through the NOS tsunami site at http://tidesandcurrents.noaa.gov/tsunami/.
Sea level processing software is discussed further
in Section 4.2.
