wet dems – lessons learned working with bathymetric data in the hawaiian islands emily lundblad...

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

questions?

www.soest.hawaii.edu/pibhmc Emily.Lundblad@noaa.gov