Remote Sensing for Coastal

Hazards

Dr. D. Mitra

Marine and Atmospheric Sciences Department

IIRS, Dehradun

NATIONAL SPACE SYSTEMS

Communication Remote Sensing

INSAT Series of IRS Series of

Satellites Satellites

Meteorology Radio/TV Broadcast Disaster Warning,

Search & Rescue System,

Natural Resources Monitoring and Management, Hazard &

Risk Assessment, Relief, Drainage Assessment and

Rehabilitation

Space Technology for National Development

Why satellite survey ?

The major components of application of satellite based data are:

•Detection, monitoring and forecasting (Preparedness)

• Monitor the event during time of occurrence (Disaster event)

•Damage assessment (Relief)

•Hazard zonation (Rehabilitation, reconstruction, mitigation and

prevention)

Only means of getting accurate, reliable and quick information due to

synoptic view and multi-temporal coverage from various space-borne

sensors with different capabilities

Disaster Management Cycle

Parameter (s) Present and future

Sensor/Satellite

Country/Agency

Coastal landuse/landforms/

Wetlands/Habitats/

Shoreline changes/

geologic stuctures/oil

slicks/marine pollution/

WiFS, AWiFS/LISS-I, II, III,

IV/PAN (IRS-1A, 1B, P2, P3,

1C, 1D) CARTOSAT-1,

RESOURCESAT-1

TM, ETM (LANDSAT-4,5,7)

PLA, MLA (SPOT-1,2)

IKONOS

India

USA

France

USA

Suspended sediments MOS (IRS-P3)

SeaWiFS (Orbview-2)

OCM (OCEANSAT)-1 OCM

(OCEANSAT-2)

Germany/India

USA

India

India

Surface currents OCM (IRS-P4)

OCM (OCEANSAT-2)

India

India

Coastal bathymetry SAR (ERS-1/ERS-2)

SAR (RADARSAT)

CARTOSAT 1 & 2

ESA

Canada

INDIA

Sea surface temperature AVHRR (NOAA)

MSMR (IRS-P4)

USA

India

THE MAJOR COASTAL PARAMETERS RETRIEVABLE FROM SATELLITES

Parameter (s) Present and future

Sensor/Satellite

Country/Agency

Wave height Altimeter

(ERS-1/ERS-2)

(OCEANSAT-2)

ESA

India

Wave direction SAR (ERS-1/ERS-2)

SAR (RADARSAT)

ESA

Canada

Wave length SAR (ERS-1/ERS-2)

SAR (RADARSAT)

ESA

Canada

Surface Wind speed Scatterometer (ERS-1/ERS-2)

MSMR (IRS-P4)

ESA

India

Surface wind direction

SAR (ERS-1/ERS-2)

SAR (RADARSAT)

ESA

Canada

Sea surface topography Altimeter

(ERS-1/ERS-2)

(GEOSAT)

(TOPEX)

(POSEIDON)

(OCEANSAT-2)

ESA

ESA

USA

USA

USA

INDIA

Chlorophyll MOS (IRS-P3)

SeaWiFS (Orbview-2)

OCM (OCEANSAT)-1 OCM

(OCEANSAT-2)

Germany/India

USA

India

India

Sept.-Oct. 1999 7

COASTAL ZONE

The coastal zone is the transitional area between land and sea. It

is a band rather than a line. The width of the band varies from

place to place and is determined by the interaction of marine

and terrestrial processes.

The zone occupies less than 15% of the Earth's land surface.

Only 40% of the one million km of coast-line is accessible and

temperate enough to be habitable. Yet it accommodates more

than 60% of the world's population.

See: UNCED 1992, Agenda 21, Chapter 17 (Oceans).

• 60 % of human population

• 2/3 of the world’s large cities

• 8 % of ocean surface

• 14 % of global ocean primary production

• 90 % of world fish catch

• 75-90 % of global sink of suspended river load

(IOCCG Report No. 3)

COASTAL ZONE AND ITS SIGNIFICANCE

THE COAST

• Of vital importance to humanity

• Essential, fragile element of the global ecosystem

• Zone of rapid transitions, gradients and variations

• Very difficult to put boundaries around

• Highly dynamic

• Subject to multiple uses

POPULATION GROWTH IN INDIA (IN MILLIONS)

0

2000

4000

6000

8000

10000

12000

14000

1 2 3

POPULATION OF METROPOLITAN COASTAL CITIES

(IN MILLIONS)

KOLKATA GREATER

MUMBAI

CHENNAI

1991

1981

1951

(Source: India 1999, A reference annual, Ministry of Information & Broadcasting, Govt. of India.)

14

12

10

8

6

4

2

Application of space technology in coastal disaster management

Disaster

Preparedness Relief Mitigation/Prevention

Cyclone Detection, monitoring and

communicating

Map extent of damage Early warning

strategies and their

implementation

Flood Flood forecasting and

communicating

Mapping peak flood

inundation areas,

identifying areas for

dropping relief aid,

setting up

communication links

Mapping sequential

inundation phases,

geomorphological

mapping of the flood

prone areas,

identification of the

vulnerable areas,

Earthquake Data base preparation within

the known seismic active

zones, detection of surface

deformation

Identification of large

associated features due

to fault rupture, damage

due to ground shaking,

liquefaction, landslides,

fires and floods

Mapping of active faults,

measurement of fault

displacements,

identification of risk

zones

Landslide Forecasting rainfall,

Monitoring the vulnerable

zones and communicating

Damage assessment Inventory of past

landslides, landslide

hazard zonation using

integrated approach

Disaster

Preparedness Relief Mitigation/Prevention

Volcanic eruption Identification of the

precursors such as fumarolic

activity, and surface

deformation, detecting

volcanic eruptions

Monitoring volcanic

activity,damage

assessment and

identifying safe areas

Volcanic hazard

assessment and risk

maps

Coastal erosion Monitoring shoreline

changes and coastal

environment

Monitoring

implementation of

coastal regulation zones

Understanding coastal

processes, mapping

zones of risks and

predicting shoreline

changes

Non-point and point

pollution

Detection and

communicating

Monitoring the extent

and communicating

Risk maps and

alternative strategies

Sea level rise Developing models using

DEM and shoreline change

predictions to identify likely

areas of inundations,

Monitoring glacial areas and

estimating run off

---------

Global monitoring of

environmental

parameters and

suggesting strategies for

combating human

induced activities

Mangrove/Coral reef

decline

Monitoring mangrove and

coral reef areas

Monitoring

implementation of

coastal regulation zones

Mangrove and coral reef

extent maps and coastal

regulation zone maps

Algal bloom Detection Monitoring and

communicating

Understanding causes

15

COASTAL HAZARDS – MAIN TYPES

Short term:

A. Cyclone - hurricane - typhoon

B. Tsunami

C. Flash flooding from river

Long term:

D. Land subsidence

E. Sea level rise

F. Coastal Erosion

Definitions : Coastal Hazards

Cyclone An atmospheric closed circulation rotating counter-clockwise in the

Northern Hemisphere and clockwise in the Southern Hemisphere.

Storm Surge An abnormal rise in sea level accompanying a cyclone or other

intense storm, and whose height is the difference between the observed level of

the sea surface and the level that would have occurred in the absence of the

cyclone. Storm surge is usually estimated by subtracting the normal or

astronomic high tide from the observed storm tide.

Storm Tide The actual level of sea water resulting from the astronomic tide

combined with the storm surge.

17

• Typhoons or hurricanes are tropical revolving storms. The are

called cyclones, when they occur in the Indian Ocean area.

• It are low-pressure systems or depressions around which the air

circulates in an anti-clockwise direction in the northern

hemisphere, but in a clockwise direction in the southern

hemisphere.

• The speed of the circulating air may exceed 33 metres per second

near the earth’s surface.

A - Hurricanes / Cyclones

Tropical Cyclone

Strong Winds Storm Surge Heavy Rain

Sea Level Rise

Damage to Flooding

Structures

Loss of Life

Destruction of Crops

IMPACT OF CYCLONE ON LANDFALL

0

20

40

60

80

100

120

1 2 3 4 5 6 7 8 9 10 11 12

BAY OF BENGALARABIAN SEA

Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec.

120

100

80

60

40

20

0

MONTH-WISE FREQUENCY OF CYCLONIC STORM FROM 1891-1999

(Total 456)

(Total 123)

INSAT IMAGES SHOWING THE CYCLONE MOVEMENT DURING 28 OCT TO 30 OCT, 1999

…...AND THE AFTERMATH

• NEARLY 3.75 LAKH Ha. INUNDATED

• ROAD, POWER AND COMMUNICATION NETWORKS SEVERELY AFFECTED IN 10 COASTAL DISTRICTS

SUPER CYCLONE OVER ORISSA

COAST

28 Oct-3gmt 28 Oct-6gmt 28 Oct-9gmt 29 Oct-3gmt 29 Oct-6gmt 29 Oct-9gmt 30 Oct-3gmt 30 Oct-6gmt 30 Oct-9gmt

INSAT 1D IMAGE SHOWING THE LANDFALL OF SUPER CYCLONIC

STORM OF 29 OCTOBER, 1999 NEAR PARADIP ON ORISSA COAST

Damage due to super cyclone of October 29, 1999 (Source Orissa Government))

Districts affected 12

Blocks affected 97

Villages affected 14643

Population affected 129.22 Lakhs

Crop area affected 18.42 Lakh Ha

Houses affected 16.49 Lakhs

Loss of life 9887

Persons missing 40

Persons injured 2507

Livestock perished 4.44 Lakhs

Fishing boats lost 9085

Fishing nets lost 22143

Damage due to Severe cyclone of October 17, 1999 (Source Orissa and Andhra

Pradesh Government):

Lives lost 198

Persons injured 402

Loss of crops thousands Hectare of land

Damage to property three lakh coconut trees uprooted and

two lakhs trees damaged

`

11 Oct 99 (Pre-cyclone) 14 Nov 99 (Post-cyclone)

Mahanadi

Delta

Orissa Orissa Mahanadi

Delta

NDVI NDVI

IRS-P4 OCM derived Normalized Difference Vegetation Index (NDVI) images for the pre and

post-cyclone period dates, showing the status of the vegetation around Mahanadi Delta.

Mangroves

Mahanadi

delta Mahanadi

delta

IRS-P4 OCM retrieved NDVI images for the cyclone affected coastal area, showing the vegetation status.

Orissa Orissa

Dec. 14, 1999 Jan. 13, 2000

Mangroves

10 April 2000 10 Feb 1999

27 Oct 2000 04 Feb 2001

08 Oct 1998

OIL SPILL DETECTION IN GULF OF KACHCHH

(IRS-P4 OCM FCC)

OIL SPILL DETECTED NO OIL SPILL (November 15, 1999)

(November 13, 1999)

OIL SPILL DETECTION IN GULF OF KACHCHH

(November 15, 1999)

IRS-P4 FCC NOAA SST

OIL SPILL DETECTED COOLER SIGNATURE

OIL SPILL DETECTION USING RADARSAT IMAGE

OIL SPILL

SHIPS

OIL SPILL DETECTION USING RADARSAT IMAGE

OIL SPILL

HIGH RESOLUTION (2.8 M) MULTISPECTRAL

IMAGERY SHOWING OIL SPILL

(Source: www.digitalglobe.com/applications/11.html)

POLLUTION DISPERSAL SEEN ON

IRS-1D LISS III OFF TRIVANDRUM COAST

(24 FEB.1999)

TRIVANDRUM

AIRPORT

POLLUTANT

PLUME

SHORELINE CHANGES ARPUND DHAMRA ESTUARY AND ENVIRONS

(PARTS OF THE MAHANADI DELTA, ORISSA COAST)

Data Used:

Shoreline

shown in

SOI map

surveyed

in 1972-74

IRS-1D LISS III

March 19, 2001

Erosion

New island

SHORELINE CHANGES AROUND THE MAHANADI ESTUARY AND ENVIRONS

(PARTS OF THE MAHANADI DELTA, ORISSA COAST)

Data Used:

Shoreline

shown in

SOI map

surveyed

in 1929-30

IRS-1D LISS III

FCC

March 19,

2001

Erosion

Accretion

Paradeep Port

Changes in spit

New

Barrier

island

Multi-temporal Changes in the Sagar Island between 1968 and 2002

Erosion (km

2)

Accretion (km

2)

1968-1996 6.44 13.519

1996-1998 7.833 15.666

1998-1999 3.021 0.482

1999-2000 0.108 17.751

2000-2002 16.598 0.001

1996-1998: Erosion trend

1998-1999: Accretion trend

1999-2000: Accretion trend

1996-2002: Erosion is dominant

The erosion trend is likely to

be continued

-20

-15

-10

-5

0

5

10

15

20

196

8-

199

6

199

6-

199

8

199

8-

199

9

199

9-

200

0

200

0-

200

2

erosion

accretion

37

Shankarpur

Mandarmani

Dadanpatrabar

Shorelines Extracted Applying Selected Techniques on

(Optical) LANDSAT ETM+ and IRS 1C LISS-III

Between 1950 to 2005

• Total accretion considerably less with respect to erosion.

Along Coast

• 85385.28 ha (3.25% to total surface area) eroded

• 77.16 ha (0.01% to total) deposited

1950-1963

1963-1990

1990-2000

2000-2005

Overall Change Detection Result at Temporal Scale

• Coastal shift for 40 cross sections are assessed

• With the total shift value classes formed and area divided into erosion-prone segments /cells

based on the spatio-temporal coastal change pattern -

Regime 1: Shankarpur to western portion of the Dadanpatrabar sector chiefly under erosional regime and

Regime 2: Eastern portion of Dadanpatrabar to rest of the study are belonging chiefly to accretional regime.

Regime 2

Regime 1

Erosional Regimes of the Study Area

Causes of Deposition and Erosion

– Tides, Waves, Rip Currents and Longshore Currents

– Sea Level Rise

– Cyclonic Storm Surge

– Anthropogenic Activities

Sand filled bags used

to build embankment at Shankarpur

Human Activities on coastal zone

Hotel on the intertidal mudflat

Construction and transport

on tidal mudflat

Fishing activities on tidal mudflat

• Tsunami Japanese word for ‘ Harbor wave’

• A series of waves of extreme length and period triggered by a

sudden displacement of the sea floor: seismic activity or volcanic

eruption

• The wave travels outwards in all directions from the source area

with speeds of over 500 km/hr

• Still it can have a velocity of over 50 km/hr and a height of 30 m

at the coast

• Several waves may follow each other at intervals of 15 - 45

minutes

Tsunami waves

Tsunami waves

• Waves are triggered by: Seismic activity / displacement of

the sea floor

Pre and post Tsunami image of Bande

Aech Region, Indonesia

Badly affected countries

Describing Ocean Waves

Tsunami Wave: V~ 1000km/s, l~800 km

Since the long-wavelength waves lose less energy a tsunami can travel transoceanic distances with only limited energy loss.

In the deep ocean the amplitude of a tsunami is a few cm to few dm on a very long wavelength: it is not felt aboard a ship or seen from air in open ocean (but can be measured by buoy or satellite altimeter).

When a tsunami approaches the shoreline the velocity decreases (D diminish) and in order to conserve energy (proportional to v and H) the amplitude increases.

HD1

2

HD2

2vD2

vD1

gD2

gD1

An Example

Tsunami Wave Example: Sumatra 2004

How long does it take to get to Sri Lanka?

Distance ~1600 km

Water Depth ~4000 m

T= 1600/713=2.2 hr

v gD 9.8* 4000 198m

s 713

km

hr

An Example Tsunami Wave Example: Sumatra 2004

How long to get to Thailand?

Distance ~500 km

Water Depth ~1500 m

T= 500/430=1.1 hr

v gD 9.8*1500 120m

s 430

km

hr

• Satellite remote sensing data is also very helpful for finding out

inundations due to tsunami. Penetration of water body because of tsunami

towards land can be easily traced from suitable remote sensing data.

• The inundation line derived from ground survey can be superimposed

over the taluk or village map using GIS to have an idea about the affected

agricultural areas, human population and infrastructure.

Tsunami inundation map around Nagapattinam area, Tamilnadu, India

The extent of inundation of seawater

depends on earthquake parameters,

nearshore bathymetry, beach profile, land

topography and velocity of tsunami

waves and their frequency. Due to these

parametric variations, the inundations

varied from one location to the other.

(E)

(N)

Inundation Extent and Run-up

Source: National Institute

of Oceanography, Goa

Unprecedented withdrawal of the sea between the

pulses of Tsunami waves at Tiruchendur and

tsunami deposits of ilmenite placers near Vattakottai, Kanyakumari coast.

Withdrawal of Sea at Sumatra region before the Tsunami

Salt affected mudflat along Gulf of Cambay

Salt water intrusion along Gulf of Cambay

Groundwater vulnerability analysis ( using model)

• Vulnerability may be defined as the degree of loss to a given element or set of elements at

risk resulting from the occurrence of a natural phenomenon of a given magnitude.

It is expressed on a scale from 0 (no damage) to 1 (total loss).

• In case of groundwater, the most useful definition of vulnerability is one that refers to the

intrinsic characteristics of the aquifer, which are relatively static and mostly beyond

human control.

• The most important mapable factors that control sea water intrusion are found to be the

following:

- Ground water occurrence (aquifer type; unconfined, confined and leaky)

- Aquifer hydraulic conductivity

- Depth of groundwater level above the sea

- Distance from the shore ( distance inland perpendicular from shoreline)

- Impact of existing status of seawater intrusion in the area

- Thickness of the aquifer which is being mapped

• A numerical ranking system to assess sea water intrusion potential in hydrological settings

has been devised using GALDIT factors. The system contains three significant parts:

weights, ranges and ratings. Each GALDIT factor has been evaluated with respect to the

other to determine the relative importance of each factor.

Well locations data pertaining to parameters like Total Depth (TD), Static Water Level (SWL), Total

Dissolved Solids (TDS), Carbonate (C03), Bi-Carbonate (HC03) and Chloride (Cl) around Bhavnagar

district have been collected from Gujarat Water Resources Development Corporation (GWRDC),

Gandhinagar, Gujarat for the year 1983 to 2003 in every five years interval for pre-monsoon (May) and

post-monsoon (October) period.

S.

no.

Total GALDIT

Score

Vulnerability Class

1

>90

Highly vulnerable

2

>70 - 90

Vulnerable

3

>50-70

Moderately vulnerable

4

<50

Not vulnerable

Population affected due to salt water intrusion (May, 2003)

601744

335881

186045

771707432472917 0 - 250

250 - 500

500 - 1000

1000 - 1500

1500 - 2000

> 2000

Population affected due to salt water intrusion (October, 2003)

652393

284824

199515

12254789002

0 - 250

250 - 500

500 - 1000

1000 - 2000

> 2000

SUMMARY

• Space technology plays a crucial role in almost all the components of disaster

management cycle.

• Coastline mapping and change detection are essential for safe navigation,

resource management, environmental protection, and sustainable coastal

development and planning.

• With the advancement of the technology more dependency of the coastal

monitoring is observed on remote sensing tools and products.

• In order to maintain the overall balance of the coastal morphology as well as

environment care and awareness is needed from every level starting from grass-

root to government level.

• Satellite data is also useful for monitoring disaster response activities,

damage assessment, reconstruction and rehabilitation.