Satellite Derived Bathymetry Dr. Thomas Heege EOMAP, Germany

Motivation  Extensive coverage, global scale  Spatial and temporal continuity  Attractive costs, rapid delivery Independent at remote/inaccessible locations ? Uncertainties quantifiable, standardized ? Which approach, which use cases ?

Outline  How does it work? Approach towards controlled SDB production  What are the uncertainties and can they be quantified?  What are the relevant applications?  What happens next?

Sentinel 2 Landsat 7/8 WorldView-2 WorldView-3 Spatial and temporal resolution of satellites IKONOS Kompsat 3 0.5m … 2m … 5m … 15m … 20m … 30m… Spatial resolution RapidEye Quick- bird Daily coverage 10 Mio 0.1 Mio

Approach for optical satellite imagery Source: DigitalGlobe WorldView-2, acquisition date: Indicative / empirical methods: Relate brightness to water depth Photogrammetric / stereo approach: Find matching points on seafloor Multispectral, physics based approach: Resolve light-transfer and retrieve optical properties

Approach for optical satellite imagery (Semi-) EmpiricalPhysical Setup & investmentEasySophisticated Location independent (In situ data not mandatory) NoYes Uncertainties traceable (independent on in-situ data) NoYes Production capabilityDependent on in situ data availability Large, highly automatable Methods Relating brightness or log-ratios to depth (e.g. Lyzenga et al., Stumpf, etc) Resolving the light transfer (e.g. CSIRO SAMBUCA, EOMAP MIP) Focus on the multi-spectral approach:

Un-corrected imagery: view at sensor Heron Island, WorldView-2 Radiances (RGB: ch4, 3, 2) Source: DigitalGlobe WorldView-2, acquisition date:

Atmospheric effects removed: view at sea surface Heron Island, WorldView-2 Reflectance (RGB: ch4, 3, 2) Source: DigitalGlobe WorldView-2, acquisition date:

Water column removed: view at seafloor Heron Island, WorldView-2 seafloor reflectances (RGB: ch3, 2, 1) Source: DigitalGlobe WorldView-2, acquisition date:

Satellite Derived Bathymetry SDB Seafloor reflectance draped over bathymetry (Heron Island) Include copyrighted material of DigitalGlobe. WorldView-2

Simulated Uncertainty of SDB: 10% CSIRO By courtesy of A. Dekker/CSIRO

Uncertainty statistics: a realistic picture? Red Sea West-Australia Caribbean Sea Arabian Gulf  Only applicable in optical shallow waters  Experience: approx. 10% ± 0.5 m  0 … max 40m

Profile 2 Courtesy of Don Ventura, © FUGRO Torres Strait, Queensland Satellite Derived Bathymetry Airborne Lidar Bathymetry

Profile 5 Courtesy of Don Ventura, © FUGRO Torres Strait, Queensland Satellite Derived Bathymetry Airborne Lidar Bathymetry

Uncertainties calculated for Lake Michigan Location: Lake Michigan 2 1

SDB Uncertainty Estimation Lake Michigan 1 2

SDB Uncertainty Estimation Lake Michigan... bottom albedo retrieval uncertainty Increase of uncertainties due to … … dark seafloor … increasing depth 1 2

Use cases: Bathymetry for coastal planning / Shell © Qatar Shell Upstream doi: /17346-MS conference-paper/IPTC MS From: IPTC conference 2014 Shell/Siermann, OGEOzine article Q1 2014: ‘Supporting Qatar Shell with the execution of onshore and offshore seismic programs’  740 sq km delivered rapidly  40cm vertical accuracy  Significant cost savings > 1Mill $  HSSE risks mitigated  Project schedule efficiently supported  Key technology to aid the planning and preparation of seismic surveys.

2m spatial resolution SDB Acquisition date: 3 rd Mar m spatial resolution SDB Acquisition date: 24 th Jan 2014 Nautical chart Scale: 1:35 000, Ed Mulitple resolutions between 0.5m and 30m grid spacing Example: Sir Bani Yas island, Abu Dhabi Sir Bani Yas Island Sir Bani Yas Island

Off-The-Shelf Bathymetry – BASEMAPS Improved transnational base maps for planning Off-the shelf catalogue Resolutions: 30m,.. 70 cm > 1 Mill sqkm mapped in 2013/2014

What happens next? Objective: Increase awareness and acceptance of satellite derived bathymetry Rapid availability also in remote areas, independent, Cost effective synthesis with hydrographic surveys Supporting initial planning or reconnaissance in hydrographic applications  SDB standards development Operational uncertainty values: prove and define Definition of SDB product and qualification categories: Quantitative depth, indicative depth, minimum depth, map representation Seafloor, Obstructions, Environment  Supporting Trans-national Base-maps and electronic data sets Large scale production of relevant SDB product categories Easy access: Integration into online portals and electronic charts Regular updates, change monitoring, multi-source integration

We acknowledge contributions from: Don Ventura, Fugro Arnold Dekker, CSIRO Thank you! Questions?