On-ground measurementOn-ground measurementof solar induced vegetation fluorescenceof solar induced vegetation fluorescence

as a step to futureas a step to futureremote sensing technologiesremote sensing technologies

A. Krumov, A. NikolovaA. Krumov, A. Nikolova

Solar-Terrestrial Influences LaboratorySolar-Terrestrial Influences Laboratory Bulgarian Academy of SciencesBulgarian Academy of Sciences

Sofia, BulgariaSofia, Bulgaria

3rd International Workshop on Remote Sensing of Vegetation Fluorescence3rd International Workshop on Remote Sensing of Vegetation Fluorescence  

7-9 February 20077-9 February 2007  

CNR, FlorenceCNR, Florence, Italy, Italy

OUTLINEOUTLINE

INTRODUCTIONINTRODUCTION

ON-GROUND ON-GROUND MEASUREMENTS: TMEASUREMENTS: TECHNICAL AND ECHNICAL AND METHODOLOGICAL TASKSMETHODOLOGICAL TASKS

LABORATORY EXPERIMENTS AT VMSYSLABORATORY EXPERIMENTS AT VMSYS

ON-GROUND ON-GROUND FLUORESCENCE FLUORESCENCE MEASUREMENTSMEASUREMENTS EQUIPMENTEQUIPMENT

Design of SPECTRAL & FLUORESCENCE IMAGERDesign of SPECTRAL & FLUORESCENCE IMAGER

OPPORTUNITIES FOR SCIENTIFICOPPORTUNITIES FOR SCIENTIFIC PARTNERSHIP PARTNERSHIP

CONCLUSIONSCONCLUSIONS

INTRODUCTIONINTRODUCTION

The fluorescence signal can be reliable tool for early detection of the The fluorescence signal can be reliable tool for early detection of the vegetation dysfunctionvegetation dysfunction

Remote sensing (RS) of fluorescence (FL) signal – challenging task Remote sensing (RS) of fluorescence (FL) signal – challenging task for RS technologiesfor RS technologies

FLEX mission – new frontier for RS instrumentation and technologiesFLEX mission – new frontier for RS instrumentation and technologies

FLEX - one of the candidates for future Earth Explorer missions! FLEX - one of the candidates for future Earth Explorer missions!

New stage of investigations:New stage of investigations:

Bio-PhysiologicalBio-Physiological

MethodologicalMethodological

TechnologicalTechnological

1-st and 2-d FLEX workshops, SIFLEX and 1-st and 2-d FLEX workshops, SIFLEX and SEN2FLEX SEN2FLEX campaigns – campaigns – major role of on-ground experiments at preliminary stagemajor role of on-ground experiments at preliminary stage

Videometric Systems Group (Videometric Systems Group (VMSYS) experience in developing VMSYS) experience in developing instruments for RS systemsinstruments for RS systems

Introducing VMSYSIntroducing VMSYS

Videometric Systems Group (Videometric Systems Group (VMSYS)VMSYS)

belongs to belongs to

REMOTE SENSING DEPARTMENTREMOTE SENSING DEPARTMENT

of of

SOLAR-TERRESTRIAL INFLUENCES SOLAR-TERRESTRIAL INFLUENCES

LABORATORYLABORATORY

BULGARIAN ACADEMY OF SCIENCESBULGARIAN ACADEMY OF SCIENCES

Introducing VMSYSIntroducing VMSYS

Main scientific activity:Main scientific activity:

development of instruments and development of instruments and systems for RS in systems for RS in optical range optical range of of electromagnetic spectrum.electromagnetic spectrum.

Designed instruments:Designed instruments:series of field spectrometers; series of field spectrometers; multi-channel spectrometric system SMP-32 multi-channel spectrometric system SMP-32 onboard “Bulgaria-1300-II” satellite;onboard “Bulgaria-1300-II” satellite;Video-spectrometric complex (VSK) “Fregat” Video-spectrometric complex (VSK) “Fregat” onboard onboard “Phobos” interplanetary station“Phobos” interplanetary station, in , in partnershippartnership with scientists from Russia and with scientists from Russia and Germany; Germany; specialised equipment for fluorescence imagingspecialised equipment for fluorescence imaging

““Phobos” Phobos” interplanetary interplanetary

stationstation

Designed instruments:Designed instruments:series of field spectrometers; series of field spectrometers; multi-channel spectrometric system SMP-32 multi-channel spectrometric system SMP-32 onboard “Bulgaria-1300-II” satellite;onboard “Bulgaria-1300-II” satellite;Video-spectrometric complex (VSK) “Fregat” Video-spectrometric complex (VSK) “Fregat” onboard onboard “Phobos” interplanetary station“Phobos” interplanetary station, in , in partnershippartnership with scientists from Russia and with scientists from Russia and Germany; Germany; specialised equipment for fluorescence imagingspecialised equipment for fluorescence imaging

Introducing VMSYSIntroducing VMSYS

TECHNICAL AND METHODOLOGICAL TASKS TECHNICAL AND METHODOLOGICAL TASKS

Creation of large network of measurement Creation of large network of measurement

points with mobile equipment for on-ground points with mobile equipment for on-ground

fluorescence data acquisition.fluorescence data acquisition.

Designing of instrumentation for on-ground Designing of instrumentation for on-ground fluorescence detectionfluorescence detection

Designing of instrumentation for on-ground Designing of instrumentation for on-ground fluorescence detectionfluorescence detection

Accurate definitionAccurate definition of technical specifications for of technical specifications for FL-measurement devices;FL-measurement devices;

Investigation of conventional sensors, optical and Investigation of conventional sensors, optical and electronic elements in order to estimate their electronic elements in order to estimate their applicability to the fluoro-sensors design; applicability to the fluoro-sensors design;

Custom design of specific elements and materials;Custom design of specific elements and materials;

Elaboration of Elaboration of fluorescence imagerfluorescence imager for on-ground for on-ground measurements.measurements.

TECHNICAL AND METHODOLOGICAL TASKSTECHNICAL AND METHODOLOGICAL TASKS

TECHNICAL AND METHODOLOGICAL TECHNICAL AND METHODOLOGICAL ACTIVITIES ACTIVITIES

Creation of large network of on-ground mobile Creation of large network of on-ground mobile instrumentation for FL data collection.instrumentation for FL data collection.

Selection of appropriate devices for monitoring Selection of appropriate devices for monitoring FL measurement conditions FL measurement conditions (Fraunhofer and (Fraunhofer and oxygen lines control, atmospheric density, excitation oxygen lines control, atmospheric density, excitation light intensity etc.);light intensity etc.);

SpecifyingSpecifying mandatory requirements to mandatory requirements to measurement instruments and methods;measurement instruments and methods;

Development of uniform format for registration Development of uniform format for registration an distribution of the measurement data;an distribution of the measurement data;

Acquiring high quality data for feeding the Acquiring high quality data for feeding the fluorescence models.fluorescence models.

ON-GROUND FL ON-GROUND FL MEASUREMENTSMEASUREMENTS

and FLEX MISSION and FLEX MISSION

Correction and validation of FLEX dataCorrection and validation of FLEX data

Adjusting data analyses and interpretationAdjusting data analyses and interpretation

Improvement of fluorescence emissions Improvement of fluorescence emissions modelsmodels

Further experiments over different Further experiments over different vegetation types or specific bioms.vegetation types or specific bioms.

Laboratory experiments at VMSYSLaboratory experiments at VMSYS

Water, drought, “acid rain” and heat stress

Influence of excitation light angle on fluorescence emission

Comparison of fluorescence and reflectance imaging as complementary tools

Coregistration effect

Fraunhofer line thematic investigation (in progress)

“…“…to develop an appropriate parameterisation of fl. intensity to develop an appropriate parameterisation of fl. intensity and it’s dependence from specific factors by isolating of each and it’s dependence from specific factors by isolating of each environment condition” (Recommendations of I-st W.S)environment condition” (Recommendations of I-st W.S)

“…“…to precisely characterise line depth and line profile in order to precisely characterise line depth and line profile in order

to accurately retrieve the chlorophyll fluorescence to to accurately retrieve the chlorophyll fluorescence to

consolidate the potential application of the O2/Fraunhofer line consolidate the potential application of the O2/Fraunhofer line

method in space.” (Recommendations of I-st W.S)method in space.” (Recommendations of I-st W.S)

““Acid rain” stress impact onAcid rain” stress impact on

birch, maple and weeping willowbirch, maple and weeping willow leaves leaves

Fluorescence

81

3

2

4

5

Investigated plants4

67

1 - 1 - CCD cameraCCD camera

2 -2 - lens lens

3 -3 - bandpass filter bandpass filter

4 -4 - ventilation system ventilation system

5 -5 - body body with a with a scattered coveringscattered covering

6 –6 – short-pass optical short-pass optical color filtercolor filter

7 -7 - light source light source

8 -8 - Image processing Image processing systemsystem

Schematic configuration of VMSYSSchematic configuration of VMSYS biochamber biochamber

Fluorescence and reflectanceFluorescence and reflectance

Comparison of the sensitivity of the reflectance and fluorescence

imaging methods.

FL images of birch leaf under drought stress impact:

in the beginning of the experiment (top),

after 4 hours (centre), and after 6 hours (bottom).

Fluorescence and excitation light intensityas a function of illumination angle θ (normalized)

20 30 40 50 60 70 80 900.0

0.2

0.4

0.6

0.8

1.0

Fl.

Inte

nsi

ty,

rel.u

n.

zenith angle, degrees

M ean A lt.A moena

Prevalent leaf orientation effect on fluorescence intensity.

Influence of excitation light angleInfluence of excitation light angle on fluorescence emission on fluorescence emission

θ

6

15

34

2

1. chamber body;2. optical light-guide with collimator;3. plant sample;4. plate, covered with BaSO4;5. CCD camera6. image processing systemθ – illumination angle.

a b c

a b c

Fluorescence images of Alternantera Amoena (top)and a maple leaf (bottom) at illumination angle θ:

a) 32°, b) 52°, and c) 72°.

COREGISTRATION EFFECTCOREGISTRATION EFFECT SONYSONY CCD CCD 2/32/3’’’’ matrix sensor, 752(h) x 582(v). matrix sensor, 752(h) x 582(v).

728 nm

-0,2

0

0,2

0,4

0,6

0,8

1

1,2

1 2 3 4 5 6 7 8 9 10 11 12 13

x-sample direction, elements

S, r

el. u

nit

s

728 nm

-0,2

0

0,2

0,4

0,6

0,8

1

1,2

1 2 3 4 5 6 7 8 9 10 11 12 13

y-sample direction, elementsS

, rel

. un

its

Parasite signals in neighbor elements - up to 50 %!!!Parasite signals in neighbor elements - up to 50 %!!!

COREGISTRATION EFFECTCOREGISTRATION EFFECT Ocean OpticsOcean Optics USB2000 spectrometerUSB2000 spectrometer

Spectral distribution of the mercury doublet.Spectral distribution of the mercury doublet.The two lines are strongly overlaid. The real gap The two lines are strongly overlaid. The real gap between them is very deep.between them is very deep.

0

1000

2000

3000

570 572 574 576 578 580 582 584 586 588 590

Intensity (counts)

Wavelength (nm)

Master: 577.21 nm, 650, 2912.89

ON-GROUND ON-GROUND FLUORESCENCE FLUORESCENCE MEASUREMENTSMEASUREMENTS EQUIPMENTEQUIPMENT

Example for a minimal set Example for a minimal set

Spectral & Fluorescence ImagerSpectral & Fluorescence Imager

Registering of fluorescence and Registering of fluorescence and reflectancereflectance

Sunphotometer (MICROTOP II)Sunphotometer (MICROTOP II)

monitoring atmosphere parametersmonitoring atmosphere parameters

HR Spectrometer (Ocean Optics)HR Spectrometer (Ocean Optics)

monitoring of Fraunhofer /O2 linesmonitoring of Fraunhofer /O2 lines

Data Acquisition & Processing SystemData Acquisition & Processing System

data storage and pre-processingdata storage and pre-processing

GPS positioningGPS positioning

SPECTRAL & FLUORESCENCE IMAGERSPECTRAL & FLUORESCENCE IMAGERDesignDesign

1 – lens

2 – diffraction grating

3 – fibre light-guide

4 – angular micropositioner

5 – linear micropositioner

6 – focal plane

7 –spectrum image

8 – narrow-band filters

9 – CCD camera

10 – interface unit

11 – interface connector.

SPECTRAL & FLUORESCENCE IMAGERSPECTRAL & FLUORESCENCE IMAGERParametersParameters

COMMON SPECIFICATIONS FLUORESCENCE

IMAGER

SPECTRAL

IMAGER

Spectral range (nm)

Spectral resolution (nm)

Size at 50mm FL lens

and 10m distance (change of

the lens is possible):

Imaging scene (m)

Scene pixel (mm)

FOV at the above conditions

IFOV at the above conditions

Full spectral cube readout

(sec)

512(H) x 512(V) x 512(λ)

Region of interest (ROI)

readout (sec)

390 – 708

0.07

2.46 x 2.46

4.8 x 4.8

14o14’36’’ – square

1.73’’ – square

256 + the scanning

time

(0.5 – 256) + the

scanning time

390 – 758

0.9

2.46 x 2.46

4.8 x 4.8

14o14’36’’ – square

1.73’’ – square

256 + the scanning

time

(0.5 – 256) + the

scanning time

SPECTRAL & FLUORESCENCE IMAGERSPECTRAL & FLUORESCENCE IMAGER

Proposed imaging spectrometric systemProposed imaging spectrometric system

can be a suitable tool for can be a suitable tool for qualitative and quantitative qualitative and quantitative estimatesestimates of the fluorescence level variation and of the fluorescence level variation and monitoring the vegetation biostatus in on-ground or air-monitoring the vegetation biostatus in on-ground or air-born experimental campaigns;born experimental campaigns;

allows allows co-registration of fluorescence and reflectance co-registration of fluorescence and reflectance signalsignal from identical field of view, and thus, could be from identical field of view, and thus, could be helpful in establishing a link with other vegetation helpful in establishing a link with other vegetation monitoring programs, based on reflectance observations;monitoring programs, based on reflectance observations;

can be constructed with can be constructed with conventional elementsconventional elements and and modules modules

could be considered as acould be considered as a prototype prototype of of basic fluorescence basic fluorescence measurement devicemeasurement device

OPPORTUNITIES FOR SCIENTIFICOPPORTUNITIES FOR SCIENTIFIC PARTNERSHIPPARTNERSHIP

Investigations of sensors, electronic and Investigations of sensors, electronic and optical elements and modulesoptical elements and modules

Designing of instrument prototypesDesigning of instrument prototypes

Testing of conventional measurement Testing of conventional measurement instrumentsinstruments

Thematic investigation of Fraunhofer lines Thematic investigation of Fraunhofer lines shape and dynamics caused by shape and dynamics caused by atmosphere phenomena atmosphere phenomena

Organising field/air-born campaigns over Organising field/air-born campaigns over different kind of bioms in Bulgariadifferent kind of bioms in Bulgaria

Scientific bases in BulgariaScientific bases in Bulgaria

Basic Environmental Observatory (BEO) MoussalaBasic Environmental Observatory (BEO) Moussala

location:location: Rila Mountain, peak Moussala - the highest peak at the Rila Mountain, peak Moussala - the highest peak at the Balkans; Balkans; altitude:altitude: 2925 m2925 m

Monitoring station (MS) AlinitzaMonitoring station (MS) Alinitza

location:location: Alinitza valley environmental reference point, Rila Mountain Alinitza valley environmental reference point, Rila Mountain Reserve;Reserve;altitudealtitude 1750 m1750 m

Research base ShkorpilovtsiResearch base Shkorpilovtsi

location:location: on the Black Sea coast, Shkorpilovtsi village, 50 km south on the Black Sea coast, Shkorpilovtsi village, 50 km south of Varna.of Varna.altitude:altitude: sea levelsea level

Airplane “Chesna” for scientific and appliedAirplane “Chesna” for scientific and applied RSRS,,

EUROSENS (Belgium) office in BulgariaEUROSENS (Belgium) office in Bulgaria

CONCLUSIONSCONCLUSIONS

On-ground measurements - integral part of On-ground measurements - integral part of FLEX space mission;FLEX space mission;

Development of reliable fluorescence imager Development of reliable fluorescence imager for field fluorescence detection;for field fluorescence detection;

Necessity of large network of mobile Necessity of large network of mobile measuring equipments for on-ground measuring equipments for on-ground fluorescence data collection;fluorescence data collection;

Enlarged international partnership, Enlarged international partnership, especially in organizing field fluorescence especially in organizing field fluorescence measurement campaigns.measurement campaigns.