2011 - Cooperative Institute for Research in Environmental Sciences ...

Figure 1: Perspective view
illustrating the spatial variability of
DEM interpolation errors resulting
from near-shore morphologic
variability. The quantification of
these errors will aid NOAA efforts
to incorporate error estimations
into improved tsunami
forecast and warning
products.
new products that promote community resiliency through better
assessments of hazards, coastal vulnerability and risk. Research
goals include the development of seamless, accurate, high-resolution
digital elevation models (DEMs) to improve the accuracy of
coastal inundation modeling; the development and expansion of
historic events databases and tsunami deposits databases; and
hazard assessments.
Milestone 1. Produce nine to 14 seamless, integrated, bathymetric–topographic
digital elevation models of select U.S.
coastal communities to support tsunami forecast and warning,
hurricane storm-surge modeling and coastal inundation
mapping.
During FY11, CIRES staff at the National Geophysical
Data Center (NGDC) developed 17 community and five
regional seamless, integrated, bathymetric–topographic
DEMs of U.S. coasts, including Alaska, Hawaii and the
Virgin Islands. These high-resolution coastal DEMs serve
as a base layer for a variety of uses including: 1) modeling
of coastal processes (storms, tsunamis, ocean currents, sediment
transport, sea-level rise, etc.); 2) ecosystems management
and habitat research; 3) coastal and marine spatial
planning; and 4) community hazard preparedness and
disaster mitigation. The coastal DEMs are used by NOAA’s
Tsunami Warning Centers, the NOAA Center for Tsunami
Research, Coast Survey Development Laboratory and the
National Tsunami Hazard Mitigation Program for computing
inundation from tsunamis and hurricane storm-surge.
CIRES staff at NGDC also developed new education and
outreach materials, including a ‘Coastal DEM Best Practices’
handout, and interactive online magazines of NGDC
coastal DEMs of various U.S. coastal regions. We also assisted
other researchers and the public with achieving their
DEM needs, including providing a Gulf of Mexico DEM
that National Geographic Magazine used as the source of
bathymetry for its October 2010 award-winning map ‘Gulf
of Mexico: A Geography of Offshore Oil.’
Current DEM research includes developing new techniques
to build different types of DEMs, quantifying DEM
inaccuracies and assessing the impact of DEM inaccuracies
on inundation mapping results. NGDC’s coastal DEMs,
accompanying technical reports and education materials
Figure 2: Clockwise from upper left: a) award-winning National
Geographic map for which NGDC contributed the bathymetry DEM;
b) DEM Best Practices handout; c) interactive online DEM magazine,
and d) perspective image of the Port Townsend, Wash., coastal DEM.
are available online at http://www.ngdc.noaa.gov/mgg/
coastal/.
Milestone 2. Investigate the effects of different gridding
algorithms and near-shore morphologic features on integrated
bathymetric–topographic digital elevation models,
and their impacts on coastal inundation that result from
tsunami modeling.
The effects of different gridding algorithms and nearshore
morphologic features on integrated bathymetrictopographic
DEMs are being quantified using a computer
program developed by CIRES scientists. The program
utilizes a split-sample methodology, in which a percentage
of the xyz points are omitted, a gridding algorithm
is applied and the interpolation errors are quantified as
the difference between the interpolated elevations and
the omitted elevations.
Products generated by the program include a grid of
the interpolation errors, a histogram of these errors and
CIRES Annual Report 2011 89