Testing Hyperspectral Remote Sensing Monitoring Techniques ...earth.esa.int/workshops/gasoil2010/Bateson.pdf · Testing Hyperspectral Remote Sensing Monitoring Techniques for Geological

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Testing Hyperspectral Remote Sensing Monitoring Techniques for Geological CO2 Storage at Natural

Seeps

Luke BatesonClare Fleming

Jonathan Pearce

British Geological Survey


In what ways can EO help with CO2

monitoring for CCS?•

Monitoring subsurface plume location•

InSAR

•

Indirect CO2

leak detection•

Vegetation analysis

•

Via effects on geology (CRIUS project in Utah)

•

Hypespectral

direct detection of CO2

•

Hyperspectral test at BGS campus•

Hyperspectral work at natural study site in Italy

•

Hyperspectral work over a large industrial source


Latera

Study Site•

CO2

GeoNet is a network of European research institutes to study Geological CO2

storage•

Remote sensing work package to study possible CO2

leak detection from a terrestrial site.

N

EW

S

1000 200 300 km

Rome

TyrrenianSea

AdriaticSea

•

Latera, Italy is a natural test site analogous to a leaking CO2

geological storage site.•

Extinct

caldera structure, known

for:•

High geothermal

gradient•

Cold

and warm

springs•

Gas vents

•

Shallow

carbonate

basement

in which

there

is

high heat

flow

leading

to

CO2

release

via thermo-metamorphism


Latera

Study Site

Latera

Gradoli

Valentano

BolsenaLake


Indirect CO2

leak detection

•

NDVI (CASI)•

Thermal (ATM)

•

Aerial photos•

Lidar

intensity

•

Vents mainly identified via changes in vegetation•

White polygons = possible vents

•

Soil gas testing of 39 of these (colour infill) •

40% of our interpretation was correct


•

CO2

absorption feature = 2.005 microns

•

On the edge of water absorption feature

•

Other atmospheric gasses do not absorb at this wavelength

•

HAWK hyperspectral sensor covers this region

•

NERC Airborne Research and Survey Facility have Eagle and Hawk sensors

Direct Detection of CO2

using Hyperspectral Data


Interpolated radiance

Measured radiance

•

Band ratio processing results in noisy image:

•

Atmospheric water vapour has an unequal absorption at the CO2

absorption wavelength (λm) and the reference wavelength (λr) .

•

Modify band ratio to account for this unequal water vapour influence…..Use a Continuum Interpolated Band Ratio


using Hyperspectral Data

mRadianceedInterpolat

mRadianceCIBR

_



using Hyperspectral Data -

Test at BGS


True Colour Image of Test Area


Anomalies detected for white tarpaulin, but also in areas of low signal to noise, such as shadow and across track illumination effects

Test at BGS –

CIBR result


Direct CO2

detection over natural leaks, Latera

•

NERC ARSF data flown in Italy in September 2007

•

Ground-truthing data also collected.•

Field spectrometer readings (ASD)

•

Soil gas flux to atmosphere •

Soil gas compositions

•

Atmospheric monitoring•

Weather station

•

Eddy covariance


ASD Measurements•

ASD used for calibration

•

ASD measurements of vegetation surface for a transect across a vent

•

ASD also used try to measure the influence of the additional CO2.

•

ASD measurement of CO2

.

•

Measurements of the spectralon

reference panel in 2 areas:•

Outside of the vent assumed no extra CO2

to be present. •

Directly over the vent, where we assumed additional CO2

to be present.

•

Measurements were made both at ground level and approximately 1 meter from the ground

•

An average was computed for each measurement, the resulting reflectance was graphed for each category:


ASD Measurements of CO2

Average ASD Reflectance values for areas with and without leaking CO2

88

89

90

91

92

93

94

95

96

1961

1968

1975

1982

1989

1996

2003

2010

2017

2024

2031

2038

2045

2052

2059

2066

2073

2080

2087

2094

Wavelength (nm)

Ref

lect

ance

Air CO2 Air No CO2

Spectralon reflectance no additional CO2

Spectralon reflectance additional CO2

Absorption Depth (reflectance %)

0.65 3.78


Latera

Hawk data•

237 spectral bands 920nm to 2500nm (Short Wave Infrared)

•

2 to 4 meter pixel size

•

About 30% of the imagery covered by shadow.

•

Main area of interest is covered by shadow!


CIBR for Latera

HAWK true colour image

CIBR using hawk band 166 (2003.04nm)

Note the noise in the shadow area

Density slice of the CIBR

White = 0.80 –

0.85

Yellow = 0.85 –

0.90

Cyan = 0.91 –

0.93

Magenta = 0.95 –

0.97


Why do we not see the CO2

in the Hyperspectral imagery?

•

Semi promising results from BGS test•

ASD results show there is a difference in absorption at wavelengths of interest

•

Possible reasons for not detecting this in Italy:•

Signal to noise ratio of the sensor

•

Cloud shadow –

low signal to noise, but still don’t see vents which are not in shadow

•

Small amount of leakage gas compared to atmospheric gas •

It does not have a large enough effect within the area of an image pixel (3-4m square)?

•

Does it disperse to quickly? –

BGS test suggests this could be a factor

• Background to the gas is too varied?


Direct detection of CO2

using satellite data

•

Freely available Hyperion data

•

Need a site with high CO2

flux to detect CO2

in a relatively low resolution satellite image.

•

Hyperion data exists over Baghdad

•

Oil refinery to south of river


Baghdad CIBR

•

Reference bands = 183 (1981.86nm) and 189 (2042.45nm)

•

Measurement band = 185 (2002.06nm)


Conclusions

•

Indirect detection works 40% of the time

•

Direct detection with HAWK sensor not giving us the results we want for a natural site•

SN ratio?

•

Would be interesting to try over a large CO2

source

•

Direct detection with Hyperion gives promising results over a large industrial site


Opportunities for CCS with future ESA Missions•

Sentinel 1 (C-band Radar) 2011.•

InSAR studies

•

2 day repeat

•

Sentinel 2 (high res multispectral) 2012.•

Vegetation stress studies

•

Geological mapping

•

Sentinel 5•

Atmospheric monitoring –

will it be sensitive enough to pick up small increases in CO2

from leaks?

•

Still need -

High resolution well calibrated hyperspectral sensors which extend into the thermal region•

Direct detection via spectral signatures

Documents

Testing Hyperspectral Remote Sensing Monitoring Techniques ...earth.esa.int/workshops/gasoil2010/Bateson.pdf · Testing Hyperspectral Remote Sensing Monitoring Techniques for Geological