1

Proposal DefenseKevin Ross TurpieDept of Geography

University of Maryland6 December 2006

Modeling directional reflectance spectra of coastal marsh vegetation

for remote sensing applications

Dr. Michael KearneyDr. Stephen PrinceDr. Michelle HoftonDr. Robert HudsonDr. David Tilley

2

Brackish and Salt Marshes

CHARACTERISTICS:

Important habitat for coastal flora and fauna.

High primary productivity (0.5 to 6.2 kg C m-2 yr-1) (Day et al. 1989).

Strong nutrient sink - reduces eutrophication.

Sediment sink - reduces silting.

Wave energy sink - protect coasts.

Key pathway of detritus and CDOM to coastal systems. (Bouchard et al. 2003, Mendonca et al. 2004)

Salinity and hydrology produce characteristic zonation.

Inundated graminaceous and herbaceous monospecific canopies.

3

ISSUES:

Sea level rise - drown marsh, increase erosion, change hydrology and salinity gradient.

Disturbances

Storms - effect hydrology, nutrient flux, erosion.

Construction - effect nutrient flux and hydrology.

Fire - can damage rhizomes, effects not fully understood.

• Invasive Species - can affect trophic, edaphic, hydological characteristics of the marsh.

Brackish and Salt Marshes

4

Statement of Problem

BRDF of vegetation canopies changes with wavelength, thus spectral features change with viewing and solar angles.

This affects remote sensing techniques that depend on the marsh spectral characteristics (e.g., classification).

This can be compensated for with a canopy RT model, but water produces BRDF affects in inundated canopies that is not handed by current models.

5

Example:BRDF Effectsfrom Water

from Vanderbilt et al. 2002,with permission

Data provided by Schill (Schill 2004).

6

WaterLevel

Spartina patens

Wavelength (nm)

Ref

lect

ance

(%

)

700 800 900 10000

5

10

15

20

25

30

Schoenoplectus americanus

WaterLevel

Wavelength (nm)

Ref

lect

ance

(%

)

0

2

6

10

12

14

16

700 800 900 1000

4

8

Data digitzed from Stutzer 2004

Example: Spectral Effects of Water

7

PROPOSED THESIS RESEARCH

Objective: Develop an RT model for the marsh canopy.

Development - Build RT model on existing work.

Validation - Validate the model against field data.

Model Inversion - Test model inversion against field data.

Closure Experiment - Test agreement of model, ground truth, and RS data.

Geometric Optimization - Optimize viewing and solar angles for best vegetation spectral signature.

8

FieldRadio-metry

FieldRadio-metry

RemoteSensingImaging

RemoteSensingImaging

Vic Cal Validation

Vic Cal Validation

Geochem Cycling Coastal Ecology

Geochem Cycling Coastal Ecology

Local Monitoring Local Monitoring

Geochem Cycling Coastal Ecology

Geochem Cycling Coastal Ecology

Invasive Species Dieback Regn Monitoring

Invasive Species Dieback Regn Monitoring

Productivity Energy Budget Climatology

Productivity Energy Budget Climatology

Tie to RS Imaging Tie to RS Imaging

Standing biomass Litter Decomposition Productivity Sub-lethal Stress

Standing biomass Litter Decomposition Productivity Sub-lethal Stress

Applications for RS

Albedo Light Field / FPAR

Albedo Light Field / FPAR

Image Comparison Classification Vegetation Indices Apps for RS

Image Comparison Classification Vegetation Indices Apps for RS

Canopy Structure Canopy Structure

Adjust forBRDF

Adjust forBRDF

InvertModelInvertModel

Adjust for BRDF

Adjust for BRDF

IntegrateModel

IntegrateModel

Role of a Marsh Canopy RT Model

9

Marsh Canopy Radiative Transfer Model

Model Selection Criteria Accounts for majority of variation in BRDF. Few input parameters. Invertible. Accessible code. Flexibility of design and implementation.

Modifications Must add aquatic background (Water RT). May need to generalize for RS applications. Any parameterization done against training data.

10

Marsh Canopy Radiative Transfer Model

SO

ILW

AT

ER

CA

NO

PY

i

Air-Water Interface

t

11

Marsh Canopy Radiative Transfer ModelSample of Existing Models

3-D

Turbid MediumKubelka Monk 1931Duntley 1942Allen Gayle & Richardson 1971Suits1972SAIL Verhoef 1984DISORD Myneni et al. 1988

Geometric OpticalCR Kuusk 1995, 1996MCRM Kuusk 1995, 1-D (Markov Chain)IAPI Iaquinta et al. 1997NADIM Gobron et al. 1997 2-Layer Kuusk 2001Ni et al. 1999FLAIR White et al. 2001

KernelRoss 1981Strahler & Jupp 1991Ross-thick Roujean et al. 1992RPV Rahman et al. 1993Walthall 1995Ross-thin Wanner et al. 1995Li-sparse Wanner et al. 1996Bicheron & Leroy 2000MRPV Martonchik et al. 2002SGM Chopping et al. 2003

HybridSAIL-H Kuusk,GeoSAIL Huemmrich 2001García-Haro & Sommer 2002

1-D

Ray-tracingRaytran Govaerts & Verstraete 1998,SPRINT Goel & Thompson

Radiosity / Rectangular CellKimes et al. 1984,DART Gastellu-Etchegorry et al. 1996Röhrig et al. 2000

12

Field DataPhase I - Locate sites and plan itinerary.

Phase II - Measurements:

Multiple monospecific canopy types.

BRF on SPP from 60º to 60º.

Plant R and T.

LAI, LAD, Height.

Soil and water samples - optics.

Tide, weather, salinity.

Digitial photos.

13

Validation and Closure

Validation Constrained optimization to fit model to validation dataset from field data.

Test hypothesis that model fitted input and results are within confidence intervals for observations.

Inversion - Invert model for comparison with field data (no constraints).

RS Closure - Compare with data at remote sensing scales. Key candidates:

AISA - airborne hyperspectral, with roll maneuver CHRIS / Proba - ESA sat with 5 angles, hyperspectral

€

C(X ) = w ρ , i, j(ρ m, i, j − ρ o, i, j )2

i =1

Na

∑ +j =1

Nw

∑ wx, i(xi − xo, i )2

i =1

Np

∑

14

Geometry Optimization

Create “pure” vegetation spectral signature. leaf reflectance and transmittance. modeled BRDF for dense canopy and “black background.”

Create synthetic dataset from field data for canopy and background conditions.

Autocorrelate veg signature across entire modeled BRDF.

Use results to identify regions of viewing and solar angles ideal for identification (e.g., spectral angle type classification).

See if inverse of the model improves in these regions.

15

Research Timeline

16

Disseminating Results

Primary Publications Proposed

17

Disseminating ResultsGeneral Structure of Proposed Dissertation

18

Literature search. Contacted and/or met with many researchers. Consulted and observed researchers doing field work. Spoke with government and other groups on marsh issues. Acquired marsh BRDF data and leaf optics and analyzed. Acquired several models and did initial experiments. Explored several coastal marshes by boat, SUV, and foot. Wrote proposal for special use permit of CBMNWRC. On science team for CBMNWRC; expected to file regular reports. Wrote proposal for CHRIS/Proba data. SpecTIR Corp has agreed to shoulder IR&D costs for AISA flight. Got approval for radiometry instruments from GSFC. Have access to lab equipment for water analysis at GSFC. Got back-up and lab equipment at USDA. Borrowing a ASD handheld spectrometer. Attended data user workshop for MISR.

Work so far…

19

Analysis of Schill BRDF datafor Spartina alterniflora

Work so far…

data from Ramsey and Rangoonwala, USGS

da

ta f

rom

Sch

ill,

TN

C

20

Compiled and ran modelsNADIMMCRMRPV, MRPV

data from Ramsey and Rangoonwala, USGS

ViewingAngle (º)Work so far…

SAILSAIL-HGeoSAIL

NADIM Run

21

Dr. Michael KearneyDr. David TilleyDr. Andy RogersDr. Fred Huemmrich, UMBCDr. Victor Klemas, U of DelDr. Richard Field, U of DelDr. John Jensen, U of SCDr. Betsy Middleton, NASADr. John Norman, U of WiscDr. Martha Anderson, USDADr. Charlie WalthallDr. Andrew Baldwin, UMCPDr. Narandra GoelDr. Wenhan QinDr. Steven Unger, NASADr. Antonio Mannino, NASADr. Wayne Wright, NASADr. Amar Nayegandhi, USGSDr. James Irons, NASADr. James Butler, NASA

Work so far…Adviser, discussions on research topic.Marsh field trip, April 2006Discussions on marsh research, 2005SAIL model, BRDF infoContacts on marsh researchTalks & meeting on marsh field workDiscussion, supported marsh RT modelField work experience and discussionDiscussion on modeling canopy RTUSDA contact, met and discussed workUSDA contact, met and discussed workInfo and advise on marsh workDiscussed modeling canopiesDiscussed modeling canopiesHyperion project scientistExperience with CDOM measurementsDiscussed flyover of LIDARDiscussed flyover of LIDARDiscussed radiometry and BRDFDiscussed goniometers, toured facility

22

Work so far…Dr. Vern Vanderbilt, NASADr. Lawrence Corps, USDARoger Stone, US FWSDr. Dixie Birch, US FWSDr. Glenn Carowan, US FWSDr. Craig Daughtry, USDADr. Nancy Adamson, U of Md CELeslie Hunter-Caro, Environmental ConcernPenny Grealy, Environmental ConcernDr. David Nemerson, National AquariumDr. LeeAnne Chandler, DNRDr. Roman Jensien, MCBPJay Charland, Assateague Coast KeeperDr. Darlene Wells, DNR/MGSDr. Fred Irani, DNRDr. Court Stevenson, UMCESDr. Steven SchillDr. Amina Rangoonwala, USGSDr. Elijah Ramsey III, USGSDr. Oliver Weatherbee, SpecTIR Corp.v

Lengthy discussion on RT and RS.Radiometric field workCBMNWRC info, tour of BlackwaterCBMNWRC info, handled proposalCBMNWRC info, proposal infoRadiometric field workContacts on growing S. alternifloraInfo on growing S. alternifloraInfo on growing S. alternifloraInfo on growing S. alternifloraContacts on critical areasTour of two coastal bay marshesTour of one coastal bay marshInfo on critical areasInfo on RS work, contacts on field workDiscussion on research topicS. alterniflora BRDF DataOptic data and papersOptic data and papersSpecTIR contact, info on AISA

23

Work so far…Dr. Francisco Artigas, MERIDr. Martha Gilmore, Wesleyan UDr. William Lawrence, BSUDr. David Diner, NASAMilton Hom, NASAAmy Jacobs, Delaware DNRDr. Ann Nolin, OSUDr. Don Deering, NASADr. Dan Kimes, NASADr. V. MartinsDr. Ray Hunt, USDADr. Susan Ustin, UCD/CSTARSDr. Mark Chopping, Montclair State UKent Lawrenson, DCAir PhotosCassy Gurbisz, CBFMatt Mullin, CBFKevin Boone, DNRDavid Hatchell, ASD Inc.Lawrence Ong, SSAIGeorgi Georgiev, SSAI

Discussed marsh spectra and instrumentsDiscussed marsh classification & collabContacts for instrument and dataMISR proj scientist, PARABOLA IIIAdvice and help with GSFC rad instInfo on marsh field workDiscussion on marsh BRDF and RSDiscussed measuring BRDFDiscussed measuring BRDF and DARTDiscussed instruments for BRDFLengthy discussion on BRDF and RSProvided paper on sun glint workLengthy discussion on BRDF field instInfo on flight cost, photos, etc.Info on KNMEC and Bishop’s HeadInfo on KNMECInfo on DNR mapping resourcesInfo on ASD resourcesContact for Hyperion dataTour and overview of GSFC goniometer

24

BACKUP SLIDES

25

Develop Model

Collect Field Data

Generate Synthetic

Data Characterization of canopy reflectance for marsh canopies

Characterization of canopy structure

parameters

Directional reflectance model for

marshes

OptimizeGeometry

Model inversion using ground truth

Validate Model

Strategy for measuring canopy

reflectance

Closure Experiment

Inversion of model using remote sensing data

Validation of optimized geometry

Task Flow Diagram

Research Products

Obtain and Process RS

Data

Validated of model for remote sensing

Flow of Planned Research Tasks and Products

26

Bishops HeadMarsh

Fishing Bay

Hoopers Strait

Crocheron

BlackwaterLake

Maple DamRoad

Study Sites

27

Schill 2000

Kuusk 2004 http://www.aai.ee/~andres/fieldwork.html 2006/12/05

Schneider et al. 2004

Kuusk 2004 http://www.aai.ee/~andres/fieldwork.html 2006/12/05

Walter-Shea, Mesarch 1998 http://snrs.unl.edu/okarmcart/Addedphotos.html 2006/12/05

28

Terminology of Radiometry

Radiant Flux(Energy / time)

€

Φ=∂Q

∂t(Joules / s or Watts)

Radiance

€

L =∂ 2Φ

∂A ⋅cosθ ⋅∂ω(Watts m-2 sr-1)

Irradiance

€

E =∂ 2Φ

∂A(Watts m-2)

29

Terminology of Radiometry

Specular reflectance

€

ρ =dΦreflected

dΦ incident

30

Bidirectional Reflectance Distribution Function (BRDF)

€

BRDF(θ i,φi;θr,φr;λ ) =dLr(θ i,φi;θr,φr;λ )

dE i(θ i,φi;θr,φr;λ )(sr-1)

Bidirectional Reflectance Factor (BRF)

€

BRF(θ i,φi;θ r,φr;λ ) =Lr(θ i,φi;θ r,φr;λ )

Li(θ i,φi;θ r,φr;λ )k

Terminology of Radiometry

31

IMPORTANT PROPERTIES OF BRDF

Inherent optical property: is independent of source or receiver.

Instantaneous quantity: can only be approximated in the real world; usually by measuring BRF.

Can vary with the wavelength of light, so spectra can change with geometry.

BRDF is dependent on:

underlying structure of the reflecting medium,

optical properties of the medium’s constituents,

optical properties of the medium’s background.

Terminology of Radiometry

32

€

r⊥ =cosθ i − nwa

2 + sin2 θ i( )1/ 2

cosθ i + nwa2 + sin2 θ i( )

1/ 2

€

r|| =nwa

2 cosθ i − nwa2 + sin2 θ i( )

1/ 2

nwa2 cosθ i + nwa

2 + sin2 θ i( )1/ 2

€

R f =1

2r⊥

2 + r||

2( )

€

Tf =1− R f

€

nwa =nw

na

€

sinθ t =sinθ i

nwa

Fresnel Reflectance and Transmittance

33

Marsh Canopy Radiative Transfer Model

Veg

Sky

UnderWater

BottomAir-

WaterI/F

Sensor

34

Backscattering Forward Scattering

Sun behind viewer Sun in front of viewer

BRDF Spectral Effects in Grass

Photos from Sandmeier et al. 1999