wet dems – lessons learned working with bathymetric data in the hawaiian islands emily lundblad...
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Wet DEMs – Lessons Learned Working with Bathymetric Data in the Hawaiian Islands
Emily LundbladNOAA Pacific Islands Fisheries Science Center
Coral Reef Ecosystem Division (NOAA – PIFSC – CRED)
and Joint Institute for Marine and Atmospheric Research
CA/HI/NV/Guam ESRI Regional Users’ Group Annual ConferenceFebruary 6 – 8, 2007
Joe Breman
previously with ESRI Redlands
NOAA’s Coral Reef Task Force (CRTF) Goal: Map and characterize coral reef ecosystems in the U.S. and flag territories by 2009
NOAA’s Coral Reef Ecosystem Division’s Goal: To achieve the CRTF goal around the Hawaiian Islands and the U.S. flag territories in the South and West Pacific.
ESRI’s Bathymetry Data Model
In planning phases with a draft globe stack
Under review by researchers, managers and developers
Satellite Altimetry
Substrate Profile
Benthic Cover
Backscatter
Rugosity
Aspect
Estimated Depth
Complexity
Slope
Soundings
Soundings
Estimated Depths
•Multibeam Surveys
•Bathymetry •Depth
•Backscatter •Substrate characteristics extracted from Bathymetry
30 kHz EM300
5000 m range135 beams
300 kHz EM3002D
150 m range250-500 “soundings”
240 kHz Reson 8101ER
250 m range101 beams
It’s like painting a room!
Large rollerSmall paint brush
Photos from: http://www.house-painting-info.com/interior-painting.html
Photos from: http://www.house-painting-info.com/interior-painting.html
Sound Velocity
Post Processing
Launch based acquisition
Shipboard acquisition
Correct for tides and movement of boat
Coral reef?
Coral reef?
Interactive Visualization Systems: Fledermaus
Backscatter
The area including Pago Pago Harbor south to Taema Bank show notable variations in acoustic reflectance.
Within the harbor, the seafloor is dominated by high backscatter values that most likely reflect the sand and mud dominated benthic environment. Small areas of low backscatter correspond with seafloor highs composed of hard substrate that are either small seamounts or carbonate edifices.
Approaching Taema Bank to the south of Pago Pago harbor, the edifices increase in abundance and are flat topped in many places.
Taema Bank is composed of mostly low backscatter seafloor, reflecting its hard volcanic and/or carbonate composition.
•Derivatives of Bathymetry
•Geomorphology
Slope
Rugosity
•Derivatives of Bathymetry: Geomorphology
Slope
Rugosity
Rugosity
Slope
Benthic Cover
Bathymetric Position Index Zones
BPI Zone and
Structure
Classification
Flowchart
Algorithm compares each cell’s elevation to the mean elevation of the surrounding cells in an annulus or ring.
Bathymetric Position Index
-3m-
|---2---| |---------4-------|resolution = 3 m
irad = 2
orad = 4
scalefactor = resolution x orad = 12
• Negative bpi = depression
• Positive bpi = crest
• Zero bpi = constant slope or flat
Bathymetric Position Index
Broad scale
Fine scale
Bathymetric Position Index Structures
Optical Validation
Sand Rock Rubble Mixed
Saipan Anchorage Groundtruthing and Bathymetry Position Index Zones
•Acoustic Mapping and Optical Validation
Challenges•Funding for remote platforms•Limited access to replacement parts•Proximity to shore•Changing platforms•Boat traffic•Ocean conditions•Endangered species•Bad charting•Sampling plans•Cross discipline data management
….. And …. The vastness of the Pacific Region
Solutions?
Remote locations, limited access, ship schedules, funding, and ocean & coastal conditions will always be a bittersweet component
Seasonal planning (ocean state & traffic) and permitting (endangered species)
Depends on NOAA’s Office of Coast Survey’s priorities:first nautical charting for NOAA – PIFSC – CRED this spring: Saipan, Tinian and Rota harbors (again, ties into remoteness of locations)
Sampling plan assessment is underway for one type of optical validation within CRED (others not yet planned, but greatly needed)
Balancing sound spatial statistics and ecological significance
Oracle database for division is under development but has not gained trust and use from Principal Investigators yet
Great need for ground up implementation of data management planneeds assessment, personnel training, PI awareness
