new approaches to retrieving soil moisture from sar data · 2017-01-30 · moisture –phase...

13
New Approaches to Retrieving Soil Moisture from SAR data Keith Morrison University of Reading Soil Moisture Workshop 25 January 2017

Upload: others

Post on 05-Aug-2020

1 views

Category:

Documents


0 download

TRANSCRIPT

Page 1: New Approaches to Retrieving Soil Moisture from SAR data · 2017-01-30 · Moisture –Phase Behaviour 0°=blue cross 10°=red square 20°=blue dot 30°=red dot 40°=green dot 50°=black

New Approaches to Retrieving Soil

Moisture from SAR data

Keith Morrison

University of Reading

Soil Moisture Workshop

25 January 2017

Page 2: New Approaches to Retrieving Soil Moisture from SAR data · 2017-01-30 · Moisture –Phase Behaviour 0°=blue cross 10°=red square 20°=blue dot 30°=red dot 40°=green dot 50°=black

Soil Moisture from SAR

• Radar remote sensing uses backscatter

• Backscatter has a dual dependence upon surface-roughness and moisture

moisture, mv

texture (sand, clay)

Page 3: New Approaches to Retrieving Soil Moisture from SAR data · 2017-01-30 · Moisture –Phase Behaviour 0°=blue cross 10°=red square 20°=blue dot 30°=red dot 40°=green dot 50°=black

Moisture Phase Sensitivity

C-band Radarsat

© C

op

yright M

acDo

nald

, Dettw

ileran

d A

ssociates Ltd

Page 4: New Approaches to Retrieving Soil Moisture from SAR data · 2017-01-30 · Moisture –Phase Behaviour 0°=blue cross 10°=red square 20°=blue dot 30°=red dot 40°=green dot 50°=black

Laboratory Investigation

Page 5: New Approaches to Retrieving Soil Moisture from SAR data · 2017-01-30 · Moisture –Phase Behaviour 0°=blue cross 10°=red square 20°=blue dot 30°=red dot 40°=green dot 50°=black

Laboratory Investigation

Page 6: New Approaches to Retrieving Soil Moisture from SAR data · 2017-01-30 · Moisture –Phase Behaviour 0°=blue cross 10°=red square 20°=blue dot 30°=red dot 40°=green dot 50°=black

Moisture – Phase Behaviour

0°=blue cross10°=red square20°=blue dot30°=red dot40°=green dot50°=black dot

Morrison,K., Bennett,J.C. and Nolan,M. Using DInSAR to Separate Surface and Subsurface Features.IEEE Transactions on Geoscience and Remote Sensing, 51, 6, pp.3424-3430. 2013.

Morrison,K. Mapping Subsurface Archaeology with SAR. Archaeological Prospection, 20, 2, pp.149–160. 2013

The phase reflecting from a sub-surface feature is:

1) linear2) independent of incidence angle

Page 7: New Approaches to Retrieving Soil Moisture from SAR data · 2017-01-30 · Moisture –Phase Behaviour 0°=blue cross 10°=red square 20°=blue dot 30°=red dot 40°=green dot 50°=black

Interferometric Model

F. de Zan, A. Parizzi, and P. Prats. A proposal for a SAR interferometric model of soil moisture IGARSS Proceedings, pages 630–633, 2012.

Page 8: New Approaches to Retrieving Soil Moisture from SAR data · 2017-01-30 · Moisture –Phase Behaviour 0°=blue cross 10°=red square 20°=blue dot 30°=red dot 40°=green dot 50°=black

Model vs. Field

ESAR AgriSAR 2006

F. de Zan, A. Parizzi, and P. Prats. A proposal for a SAR interferometric model of soil moisture IGARSS Proceedings, pages 630–633, 2012.

Page 9: New Approaches to Retrieving Soil Moisture from SAR data · 2017-01-30 · Moisture –Phase Behaviour 0°=blue cross 10°=red square 20°=blue dot 30°=red dot 40°=green dot 50°=black

Virtual Bandwidth SAR

(VB-SAR)

6.4GHz

Page 10: New Approaches to Retrieving Soil Moisture from SAR data · 2017-01-30 · Moisture –Phase Behaviour 0°=blue cross 10°=red square 20°=blue dot 30°=red dot 40°=green dot 50°=black

VB-SAR – First Demonstration

Drying sandy loamC-Band, imaging geometry i=20°

Δmv=0.098 to 0.027

Real Bandwidth 0.15GHzVirtual bandwidth 3.38GHz

Page 11: New Approaches to Retrieving Soil Moisture from SAR data · 2017-01-30 · Moisture –Phase Behaviour 0°=blue cross 10°=red square 20°=blue dot 30°=red dot 40°=green dot 50°=black

SAR Image

Page 12: New Approaches to Retrieving Soil Moisture from SAR data · 2017-01-30 · Moisture –Phase Behaviour 0°=blue cross 10°=red square 20°=blue dot 30°=red dot 40°=green dot 50°=black

VB-SAR Image

Page 13: New Approaches to Retrieving Soil Moisture from SAR data · 2017-01-30 · Moisture –Phase Behaviour 0°=blue cross 10°=red square 20°=blue dot 30°=red dot 40°=green dot 50°=black

Summary

Interferometry of soil shows:

• definite moisture-phase relationship

Understand phase change as:• return from within soil• surface return little changed• due to changing dielectric = proxy for moisture

Opportunities• added-value of backscatter-derived moistures• new insights• moisture profiles• sub-surface imaging

Exciting “discovery” phase:

• Groups to watch - University of Reading, ETH-Zürich, DLR.