Satellite bathymetry and

other satellite derived data

Per Knudsen, Ole Andersen, Rene Forsberg,

Roberto Saldo, & Henning Skriver

Space and the Arctic

Two major meetings were held in March 2012:

• Space for the Arctic '12

• IAP Applications for the Arctic Workshop

to discuss the contribution of space technologies to one of

the regions most affected by climate change. Co-

organised by Arctic nations, ESA and EC.

“Space systems offer opportunities for monitoring

the environment, facilitating navigation and

communications, enhancing marine safety and

supporting sustainable exploitation of national

resources. Jean-Jacques Dordain, ESA Director

General.”

Space and the Arctic

Both meetings focused on the objectives:

1. To identify operational user needs in the Arctic region.

2. To help to establish operational services in the Arctic

in areas where integrated applications are relevant:

a) Oil and Gas.

b) Shipping

c) Fishing.

d) Search and Rescue.

e) Telemedicine.

f) Tourism

3. ..

Space and the Arctic

Several specific recommendations that should be taken up

by the Arctic stakeholders came out of ‘Space for the

Arctic 2012’, including

• higher bandwidth satellite telecommunication channels,

• improved satellite-based navigation systems, and

• trans-Arctic monitoring of sea ice and icebergs

to increase safety of navigation.

Space and the Arctic

Gaps have been identified that have to be addressed to

support the policies and commitments of European and

Canadian states and the EU in the Arctic:

• Secure the implementation of the GMES programme

• Act to ensure High bandwidth communications

• Investigate means such as Galileo Arctic test-bed to

ensure High reliability navigation above 75ºN

• Ensure continuity and development of Arctic

meteorology and space weather

Collaboration and partnership are fundamental with the

development or improvements of networks

Developing satellite based

infrastructures for the Arctic

Galileo – a GNSS including a ground system to

ensure:

• Positioning with integrity information

• Search & Rescue

GMES - Actual, reliable, standardised

information about the environment based on

Earth observation and in-situ data:

• MyOcean – the marine GMES service

• Safer – emergency management

Galileo - components

• 30 satellites at 23,200 km altitude

• A series of control stations on

ground (RIMS)

• 5 frequencies, 10 navigations

signals, and Search-and-Rescue

• EC / European GNSS Agency +

operators

• Service providers

• Users

Galileo – services

Galileo is designed for 5 different services, targeting different user segments:

• Open Service – freely available for all

• Safety of Life – higher quality and integrity, increased security

• Commercial Service - for professional users, high quality and service guaranty

• Public Regulated Service - Encrypted og robust to jamming

• Search and Rescue (SAR) – Emergency signals and supporting rescue operations.

Galileo – implementation

• On 21.October 2011 the first two

Galileo IOV satellites were launched.

• The next two will follow on 12/10 2012.

• 18 satellites and FOC-1 in 2015.

• 24+ satellitter and FOC in 2019.

Galileo – Arctic Testbed

Project in the European GNSS Evolutions Programme:

• The objective is to develop and deploy an Arctic

TestBed to support Galileo services over ARCTIC

regions.

• Lead: Kongsberg Seatex

• Supported by Kartverket, U Calgary, and DTU (develop

net of ground stations, improve iono models, and

testing)

• 2012-2014

Earth observation

Develop GMES:

• Explore missions, such as GOCE and

Cryosat-2

• Develop applications and products

• Establish services, such as MyOcean

• Operate observation networks

• Sentinels

• In-situ

Operational – soon..

Satellite bathymetry

Information about the bathymetry may be

derived from:

• High resolution images,

• Lasers (air borne demos),

• Radars:

• SAR (wave studies),

• Altimeters (gravity inversion).

Coastlines

E.g. GRASS (a small Danish company) offer analyses of

coastline changes.

• Recently declassified US spy satellite images combined

with modern high resolution satellite images, provides long

time series of coastal development.

• This will allow an analysis of coastline changes in the

period 1960-2005 and an accuracy of app. 15 metres.

• Higher accuracies can be obtained with SPOT which is

available in the period 1986 to present. In this way

accuracies can be within 5 metres.

• Using QuickBird data with a spatial resolution of 60 cm,

the results are comparable to aerial photography.

Coastlines

• Contain information about bathymetry, obviously.

Satellite bathymetry

Fugro NPA have extensive experience of

bathymetric mapping using satellite imagery in

shallow water areas.

Satellite bathymetry

WorldView-2 from DigitalGlobe provide 1.84 m resolution multi-spectral

imagery, plus a Coastal Blue detector focused on the 400 – 450

nanometer spectral range.

With the Coastal Blue band included it is be possible to calculate depths

up to 20 m and potentially as deep as 30 m, by measuring relative

absorption of the Coastal Blue, Blue and Green bands.

Laser bathymetry – air-borne

Infrared laser .. surface

Green laser ... Sea bottom .. Down to 2-50 m

Theoretical sea surface: geoid (gravity field

equipotential surface ... If known green ok)

Commercial systems:

Optech-Shoals (Canada)

LADS (Australia)

Hawk-Eye (Sweden/UK)

Commercial systems

New instrument #1:

Photon counting – SigmaSpace ”icemapper”

(prototype for proposed NASA Jupiter moon

mission

10x more effective than present systems (less

power needed)

3 cm accuracy in timing, 2000 m+ flight elev

15 deg scanning

60 kg in rack

Flown in Antarctica Feb 2011

Solution for Arctic bathymetry needs ? Laser tests in Antarctica

(Univ. of Texas / DTU-Space)

Laser bathymetry – air-borne

NOAA's contractors use LIDAR to collect near shore

bathymetry in Alaska, the North Atlantic Coast and the

Caribbean. Future developments include improving object

detection capabilities to better identify near shore hazards

to navigation.

• Depending on water clarity, these systems can reach

depths of 50 meters.

Satellite bathymetry - radars

Using geophysical methods space-borne radars

may be used:

• SAR or other imaging radars to study waves:

• Changes in wavelengths due to shallow

waters

(no examples)

• Altimeters measuring marine geoid undulations:

• Changes in gravity due to changes in

bathymetry such as reefs and sea mounts.

• Principle of using Gravity to predict Bathymetry

(From Sandwell/Smith)

Satellite bathymetry - altimetry

• High Quality MSS/Gravity field can be used to map bathymetry.

• Using Spectral sepration throught filtering (20 and 120 km)

• Adjusting wavelength 20 km – 120 km based on DNSC08 gravity

optimizing coherency (outside these bands GEBCO-1 is used)

• Adjusting depth where GEBCO-1 > 100 meters.

(Figure from Sandwell/Smith)

Satellite bathymetry - altimetry

Comparison with Polar Stern Bathymetry

11.981 obs Std Dev.

(meters)

Max difference

(meters)

ETOPO 5 (5 minute) 531 3014

ETOPO 2 (2 minute)

(Altimetry enhanced)

243 1642

GEBCO – 1 minute 201 1792

DNSC08 – 1 minute 132 1188

Survey example around Antarctica

GEBCO-1 Global Bathymetry

On satellite bathymetry

None of the (space-based) methods described

above may work:

• as stand-alone hydrographic surveying tools,

• in areas covered by sea ice.

Satellite based method may support the

hydrographic mapping by identifying areas of

interest.

Other relevant satellite data

ESA Explore missions:

• GOCE:

• Gravity for ocean circulation

• SMOS:

• Salinity

• Cryosat:

• Sea ice – also thickness

• Ocean topography/geoid

Sea ice thickness from Cryosat

MyOcean services

MyOcean provide products for

• Maritime safety

• Marine resources

• Coastal and marine environment

• Weather, climate and seasonal forecasting

Examples:

• Temperature

• Salinity

• Currents

• Sea level

• Sea ice

Seaice.dk - 5-10-2012

Seaice.dk – 5-4-2012

Seaice.dk – 5-9-2012

Space and the Arctic

Gaps have been identified that have to be addressed to

support the policies and commitments of European and

Canadian states and the EU in the Arctic:

• Secure the implementation of the GMES programme

• Act to ensure High bandwidth communications

• Investigate means such as Galileo Arctic test-bed to

ensure High reliability navigation above 75ºN

• Ensure continuity and development of Arctic

meteorology and space weather

Collaboration and partnership are fundamental with the

development or improvements of networks