high resolution bathymetric mapping of the indian exclusive economic zone
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High resolution bathymetric mapping of the Indian Exclusive Economic Zone. Abhishek Tyagi, Dr. John Kurian P. National Centre for Antarctic and Ocean Research Ministry of Earth Sciences (Govt. of India) Headland Sada, Vasco da Gama, Goa-403 804. - PowerPoint PPT PresentationTRANSCRIPT
High resolution bathymetric mapping of the Indian
Exclusive Economic Zone
Abhishek Tyagi, Dr. John Kurian P.
National Centre for Antarctic and Ocean ResearchMinistry of Earth Sciences (Govt. of India)
Headland Sada, Vasco da Gama,Goa-403 804
Under the United Nations Convention on Law of the Sea (UNCLOS), the Exclusive Economic Zone or EEZ is covered by Articles 56, 58 and 59.
The UNCLOS or the Law of the Sea Treaty, is the international agreement that defined the limits of the territorial seas of nations and the areas in which they could exploit marine resources.
The EEZ is defined as that portion of the seas and oceans extending up to 200 nautical miles in which coastal States have the right to explore and exploit natural resources as well as to exercise jurisdiction over marine science research and environmental protection.
3
REGIMES CHART
1000
2000
3000
5000
4000
Oceanic crust (basalt)
Shelfedge
Geologicalslope
GCCS (4)LLLaaannnddd
Continental crust (granite)
Base ofthe slope Geological
rise
GCHS (26-30) High Seas
3Nautical Miles
12Nautical Miles
24Nautical
Miles
200Nautical
Miles
0
Depth inmeters
OOOccceeeaaannn
UNCLOS (3)
UNCLOS (33) UNCLOS (57)
UNCLOS(87,112-115)
High Seas
UNCLOS (79,113-115)
TerritorialSea
ContiguousZone Exclusive Economic Zone UNCLOS (58, 113-115)
LEGAL REGIMES :UNITED NATIONS LAW OF THE SEA CONVENTION 1982 (UNCLOS) GENEVA CONVENTION ON THE HIGH SEAS (April 29, 1958) (GCHS) GENEVA CONVENTION ON THE CONTINENTAL SHELF (April 29, 1958) (GCCS)
Continental MarginsFrom the land, submerged edges of the continents :• Continental shelf – nearly flat, gradual seaward slope; covered with sediments• Continental slope – steeper seaward slope; submarine canyons• Continental rise – 0.5° - 1° slope ; composed of sediments
Main Regions include: Continental Margins, Deep-ocean Basins, Mid-ocean Ridges
Deep-Ocean Basins
Beyond the continental margins, ocean floor deeper than 2000 m:• Abyssal plains – very flat areas at depths of 3-5 km• Seamounts – underwater volcanoes, > 1000 m high• Deep-sea trenches – steep-sided, long, narrow depressions
Mid-Ocean Ridges
• Underwater mountain ranges that are the longest on earth• Occupy 1/3rd of the ocean floor• Contain rift valleys at the summits as well as many fracture zones, where
rocks have cracked and slid past one another
Bathymetry is Basic Information
•Bathymetry provides information about water depth
•Bathymetry gives a descriptive picture of the ocean bottom terrain, revealing the size, shape and distribution of seabed features
APPLICATIONS:•For Science
Oceanography, geology, biology, ecology• For Economics and Infrastructure
Resource exploration, cable routing, shipping• For Management and Policy
Fisheries, Maritime Boundaries, Marine Protected Areas
• Defence & Sovereignty issues
HMS Challenger-first to study bathymetry in parts of all the oceans except the Arctic Ocean
Achievements:• the first systematic attempt to chart the basins of the world ocean• 492 bottom soundings
Echo sounder (also called SONAR) • Invented in the 1920s • Primary instrument for measuring depth • Reflects sound from ocean floor
Echosounder Operation
•Positioning using GPS• Uses acoustic energy (sound)• Pulse of sound travels through the water column• Lapse in time converted into distance
(Source: http://tidesandcurrents.noaa.gov/images/hydro_ship.png)
http://www.earthguide.ucsd.edu/earthguide/diagrams/sonar/sonar.html
Technologies have evolved to survey the ocean floor more accurately & widely
Spaceborne
Bathymetric Mapping Tools
Airborne
Shipborne
10,000m
2m
NEARSHOREOFFSHORE
barrierreef
lagoon fringingreef
TideGauge
Hull-mounted vs towedHull-mounted (i.e., most swath bathymetry systems):
• Fixed mounted on the ship; don’t require repeated deployment
• Can collect data while ship is being used for other purposes (e.g., physical oceanographic cruise)
• Fast surveying (ship can travel at ~10 knots)
• Acoustically noisy (near-surface turbulence and ship noise)
• Resolution constrained by near-sea-surface location
• Hard to access for repairs, and
• Compatibility with certain hull shapes
Hull-mounted vs towedTowed (i.e., most sidescan sonar systems):
• Location of fish with respect to ship must be measured or calculated
• Deployment/retrieval, ship speed must be slow ~2 Knots
• Operate in quieter water at greater depth
• Easier to move from ship to ship
• Must be deployed each cruiseSidescan sonar
Multibeam sonar
(Source: http://www.nauticalcharts.noaa.gov/hsd/images/SW_WhatIs_image.jpg)
INDIAN EEZ MAPPING PROGRAMME To prepare a comprehensive seabed topographic map for the entire EEZ
of the country using the multibeam swath bathymetric systems.
NCAOR Responsibilities
Bathymetric survey beyond 500m, data interpretation, analysis, maps preparation etc.
Archival of all data collected by the participating institutes.
Participating Agencies
NIO, Goa - Shallow waters (West Coast) NIOT, Chennai - Shallow waters (East Coast & Andaman region)
Vessel’s utilised for Deepwater Survey ORV Sagar Kanya RV Sagar Nidhi RV Ak. N.
Strakhov
• Indian EEZ covers about 2.37 million km2
• 12th largest EEZ in the world
• The MBES technology requires different set of instruments with different operating frequency and technique to undertake bathymetric surveys for shallow and deep water regimes and since the Indian EEZ is having a wide range of bathymetric depths (i.e., upto ~4000 m), the entire EEZ has been divided into two segments viz. Segment-I with areas having bathymetric depth less than 500 m, and Segment-II with areas having bathymetric depth more than 500 m.
• Technically, shallow waters, less than 500 m water depth need to be surveyed using higher frequency MBES systems while the deep-waters more than 500 m water depth need to be surveyed with lower frequency systems.
• To understand the source of sediment fluxes, their transport mechanisms and to assess the potential of seabed resources, sediment samples are also being collected in a systematic manner during the course of the surveys. Analysis of the sediment samples essentially aid to assess the potential resources as well as to reconstruct the palaeoceanographic conditions and paleoclimatic history.
Description Area (sq. km.)
Total Area of Indian EEZ (Source: World EEZ-v4) 2372298
Area with more than 500 m depth 1875378
Area with less than 500 m depth 496920
Area of EEZ around Mainland (East coast and West coast) 1697775
Area of EEZ around Andaman & Nicobar Islands 684933
Details of Indian EEZ areal extents
Implementation
Segment-I : Upto 500m depth
Segment-II: Beyond 500m depth
Vessel ORV Sagar Kanya
RV Sagar Nidhi
RV-Akademik Boris Petrov
RV-Akademik Nikolaj Strakhov
Make L3-Comm. Elac-Nautik
Reson Atlas Elektronik Reson
Model SB3012 Seabat 7150 Hydrosweep-DS2 Seabat 7150Frequency of operation 12 kHz 12 KHz 15 kHz 12 kHz
Number of Beams 201 Upto 880 59 / 240 (HDBE) 234
Swath Coverage Upto 5 x Depth Upto 5 x Depth Upto 3.5 x Depth Upto 5 x DepthBeam Width Upto 140° Upto 150° Upto 120° Upto 150°Beam Width 1° 2° 2.3° 2°
Depth of performance Upto 11,000m Upto 10,000m/ 6000m
Upto 10,000m Upto 10,000m/ 6000m
Acquisition software Hydrostar PDS2000 Hydromap Online PDS2000Post processing Eiva NaviPac PDS2000 Hydromap Offline PDS2000
Specifications of MBES used for deep water surveys
In India, the first multi-beam ‘Hydrosweep-DS’ system was installed onboard Oceanographic Research vessel (ORV) SAGAR KANYA in 1990
Vessel RV Sagar Sukti RV-Sindhu Sankalp
CRV- Sagar Purvi
CRV-Sagar Pachimi
Make Kongsberg Kongsberg Kongsberg Reson
Model Simrad EM1002 Simrad EM1002 Simrad EM1002 8101
Frequency of operation 95 kHz 95 kHz 95 kHz 240 kHz
Number of Beams 111 111 111 101
Swath Coverage Upto 7 x Depth Upto 7 x Depth Upto 7 x Depth Upto 7.5 x Depth
Beam Width Upto 150° Upto 150° Upto 150° Upto 150°
Beam Width 2° 2° 2° 1.5°
Depth of performance Upto 1,000m Upto 1,000m Upto 1,000m Upto 300m
Acquisition software Neptune Neptune Neptune PDS2000
Post processing SIS, Cfloor SIS, Cfloor SIS, Cfloor PDS2000
Specifications of MBES used for shallow water surveys
•During the course of the high-resolution multibeam bathymetric mapping of the Indian EEZ, several geomorphological, structural and tectonic features have been mapped including ridges, seamounts, knolls, abyssal hills, levees etc.
•Some of the known features are now mapped with enhanced accuracy and resolution, hence providing better ideas about geomorphic and evolutionary history.
•Integrated analysis of the bathymetric data, coupled with geological and geophysical information from the region would provide new insights into the regional tectonics, tectonic evolutionary history and basin evolution.
• Revealed presence of a new channel-levee system in the lower fan region of Bay of Bengal. Preliminary analysis of the data inferred that these submarine channel-levee systems have served as pathways for turbidity currents and other sediment-gravity flows to transport and deposit sediments from the continents to deep basins of the Bengal Fan.
•Parts of the Ninetyeast ridge and Laccadive ridge have also been mapped and better resolution geomorphologies of these sections have been prepared.
THANKS
Results