NCAV

EO 2

004

- 200

7

NCAVEO : achievements of the last three years and plans

for the future

E J Milton1, N.P. Fox2 & S. Mackin2,3

1School of Geography, University of Southampton2National Physical Laboratory

3Surrey Satellite Technology Ltd.

NCAV

EO 2

004

- 200

7Network for Calibration and Validation of

Earth Observation data

• Established in September 2004.

• 12 initial partners, now 24, drawn from academia, industry & commerce.

• Representative Steering Committee.

• Aim to promote the calibration and validation of EO data (cal/val).

• Calibration : based on physical units, traceable with known uncertainty through an unbroken chain to primary standards.

• Validation : comparison between data products produced by EO and those created by conventional methods (QA).

NCAV

EO 2

004

- 200

7Objectives of the network

• Develop a resource base to support cal/val activities – case studies, database of instruments, field sites, annotated bibliography etc.

• Share best practice in cal/val.

• Engage the wider community.

Website : www.ncaveo.ac.uk

2006 NCAVEO Field Experiment

NCAV

EO 2

004

- 200

7

NCAV

EO 2

004

- 200

7

NCAV

EO 2

004

- 200

7

NCAV

EO 2

004

- 200

7NCAVEO map of UK terrestrial cal/val sites

NCAV

EO 2

004

- 200

7Aims of the experiment

• To gain experience in the collection and use of field data to validate radiance and reflectance products, including issues of traceability and the propagation of error;

• To gain experience in methods to validate the LAI of agricultural crops derived from EO;

• To assemble a quality-controlled multi-scale, multi-sensor data set for algorithm development and testing.

48 scientists from 20 organisations.

NCAV

EO 2

004

- 200

7Choice of site : Chilbolton, Hampshire

• Study area 9km x 6km.• Includes the UK AERONET site at the Chilbolton

Facility for Atmospheric & Radio Research (CFARR).

• 3GHz Doppler-polarisation radar, 1275MHz clear air radar, UV vertical sounding lidar and more...

NCAV

EO 2

004

- 200

7

• Calibration lab established on-site:• NPL Transfer Standard Absolute

Radiance Source (TSARS).• Wavelength calibration standards.• Reference panel calibration: on-

site using ASD contact probe, post-hoc at FSF, Edinburgh.

Traceability chain for radiometric measurements

• Large area reference standards:• 6m x 6m plastic sheets• 40m x 40m area of clean concrete.

NCAV

EO 2

004

- 200

7RS data successfully acquired

Date Platform and Sensor

9th June Digital multispectral air photography

10th June SPOT-5 HRG

13th June DMC Nigeria-1

17th June

• CASI : Environment Agency• CASI : NERC ARSF• LiDAR : Environment Agency• Digital air photos• Aisa Eagle & Hawk : NERC ARSF• CHRIS/PROBA• DMC UK

14th July DMC AlSat

NCAV

EO 2

004

- 200

7Timeline for ‘golden day’, 17th June 2006

08:00 09:00 10:00 11:00 12:00 13:00

Sky irradiance distribution

DMC UK

CHRIS PROBA

EA CASI and LiDAR

NERC CASI & AISA Eagle/Hawk

Spectral grounddata

Aerosol optical thickness & water vapour amount

NCAV

EO 2

004

- 200

7Ground data collection

Mean LAI Std Error

Oats 5.06 0.103

Wheat 3.72 0.102

Barley 1.90 0.078

NCAV

EO 2

004

- 200

7Chilbolton EA CASI & Air Photos 17th June 2006

© EA, 2006

NCAV

EO 2

004

- 200

7NERC ARSF CASI data 17th June 2006

© NERC, 2006

NCAV

EO 2

004

- 200

7Irradiance variability on 17th June

Constant panel : Band 2 (500nm)

0

200

400

600

800

1000

1200

1400

1600

1800

200008

:39:

00

08:5

0:00

09:0

1:00

09:1

2:00

09:2

3:00

09:3

4:00

09:4

5:00

09:5

6:00

10:0

7:00

10:1

8:00

10:2

9:00

10:4

0:00

10:5

1:00

11:0

2:00

11:1

3:00

11:2

4:00

11:3

5:00

11:4

6:00

11:5

7:00

12:0

8:00

12:1

9:00

12:3

0:00

DN

va

lue

DMC CHRIS

EANERC

NCAV

EO 2

004

- 200

7Subset of UK-DMC image from 17th June 2006

Andover

Winchester

NCAV

EO 2

004

- 200

7CHRIS/PROBA off-nadir 17th June 2006

FZA = 36 degrees

FZA = -36 degrees

FZA = 36 degrees.Satellite north of test site.

FZA = -36 degrees.Satellite south of test site.

© SSTL/ESA, 2006

© SSTL/ESA, 2006

NCAV

EO 2

004

- 200

7Data management and archiving

• Standardised metadata.• Non-proprietary formats: HDF,

netCDF, PDF.• Spectra in ENVI spectral libraries.www.neodc.rl.ac.uk

NCAV

EO 2

004

- 200

7Organisational achievements of the field experiment

• Probably unique in UK context. Brought together 48 scientists from 20 organisations in a single, focused field experiment.

• Three organisations flew aircraft over the site. Two acquired satellite sensor data specifically for the experiment.

• 19 field teams worked for between 1 and 10 days collecting spectral & biophysical data.

• Demonstrated commitment to cal/val across different disciplines and within different organisations.

NCAV

EO 2

004

- 200

7Scientific achievements of the field experiment

• On-site cal lab revealed differences between some of the five spectrometers used – calibration errors, response to temperature changes etc.

• Field comparison revealed different results from the three Microtops sunphotometers used.

• Four groups currently working on journal papers from the expt:

1. Overview paper

2. Radiometry & calibration

3. Validation of crop LAI

4. RS for river channel habitat survey

NCAV

EO 2

004

- 200

7Overall achievements of NCAVEO

• Brought together individuals from academia, industry & government interested in cal/val.

• Allowed them to determine how ‘knowledge transfer’ can best be achieved:

• Cal/val information in a form that can be used immediately – exemplars etc.

• Shared practical activity – experiential learning.

• Large dataset with high quality metadata.

• Implementation & dissemination of results from the CEOS WGCV and from other international activities (e.g. VALERI project).

NCAV

EO 2

004

- 200

7What next?

• Funding for NCAVEO finishes at the end of September 2007 (NERC K-T grant).

• Website will be maintained until the end of September 2008.

• Datasets from the experiment will be available to the wider community from January 2008.

• UK cal/val test site(s)?

• Future field experiments?

Thank you to the NCAVEO Partners: