Geoscience Reference
In-Depth Information
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One-minute data are not currently quality controlled to the same level as the six-
minute data.
•
No formal long-term archive for the TWC coastal water level data is in place, although
a minimal-service archive of the PTWC Hawaiian sea level data is being maintained
and some of the TWC data reach the IOC's Sea Level Station Monitoring Facility.
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Retrospective data from the TWCs cannot be easily accessed.
The absolute time accuracy of 15-second data (30s Nyquist period) should be 0.035 sec-
onds if archival or even near-real-time data are to be processed between stations using correla-
tion or coherence methods. Time accuracy at this level is required in order to preserve phase
relationships at the highest observed frequencies (i.e., 1/(2*15) Hz). Such absolute accuracy is
not dificult to achieve.
Recommendation:
The committee endorses the following recommendations of the
NTHMP report (National Tsunami Hazard Mitigation Program, 2007) for the TWCs to:
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Create a formal data archive for both CO-OPS and TWC data and metadata, including
15-second data.
•
Address 1-minute and 15-second quality control issues in unison with the archive issue
to ensure quality of archive.
•
Enact Federal Geographic Data Committee (FGDC)-compliant station metadata.
•
Create an operational website providing a portal for 15-second tsunami station water
level data.
This committee did not undertake an assessment of the processing, distribution, archiving,
and long-term access to tsunami-relevant sea level data originating from international sea
level stations. As previously stated, the near-real-time, tsunami-relevant sea level data available
to the TWCs via the GTS (and archived at the IOC's SLSMF; http://www.vliz.be/gauges/) is not
quality controlled.
Conclusion:
Despite the excellent accomplishments by NOAA with respect to improving
the processing, distribution, archiving, and long-term access to the tsunami-relevant sea
level data that it collects, there remain several inadequacies. There is currently no routine
acquisition, quality control, or archiving of the 15-second NOS/CO-OPS data, which are
most relevant for model validation. In addition, NOS/CO-OPS 1-minute data are not
currently quality controlled to the same level as their 6-minute data; and no formal long-
term archive for TWC coastal water level data exists.
Description of the Deep-ocean Assessment and
Reporting of Tsunamis (DART) Network
To ensure early detection of tsunamis, especially where the coastal sea level network is
sparse or nonexistent, and to acquire data critical to near-real-time forecasts, NOAA has placed
