Cassie Presentation
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Transcript of Cassie Presentation
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Conversion &
Calibration:
Cassie Knierim
Student Airborne Research
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Overview
vBac kg round In for mati onvImportancevObjec ti ve s
vData C ol lecti onvMAST ER and i n the fi eld
vAnalysisvCon ver ting fr om radi ance to temp er at ur esvCali br at ionvMo de ls to ap pr oxi mate cano pytemp er at ur e
vConclusion
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Importance
vStu die s show th e le af tempe ratu res ofhealthy plants will be a few C lessth an a ir t emper ature .vIn w ater -st re ssed agr icult ur alregi ons , li ke Ke rn Coun ty, CA,eff ici ent and pr eci se irriga tion pl ansare re qu ired.vNumerous indi ces ex ist forde ter minin g rela tiv e p la nt hea lthvmany requi re accur at e cano py
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Local ThermalMeasurements
Advantages:
6. Better accuracy (less atmosphericeffects, etc.)
7. Better spatial resolution
Disadvantages:
12.Small field of view Inefficient for irrigation
planning in larger fields14.Thermal guns are expensive
Remote ThermalMeasurements
Advantages:
5. Increased field of view Better for irrigation plans of
large field7. Free satellite images available
daily
Disadvantages
11.Poor spatial resolution12.More calibration required for
accurate results
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Objective
vCon vert a nd ca li br ate th e rem otelysen sed da ta f rom th e M ASTER i ntoaccu ra te can op y tempe ratu res forth e a lmon d f ield for u se i n stu dy ingcrop h ealth .
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Data CollectionIn the Field
St udy si te: Almo nd Fi eld snear Lost H ills, Califor niaFi eld Day: 7/2 2/0 9
C
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Data CollectionIn the Field
Cali br at ion Si tes :CAL1, CA L2 = Bare Soi lCAL3, CA L4 = W ate rMea su red te mper atur e in a gr id p att ern(~ 10m 2/g rid bo x)
T1 T4 T7
T2 T5 T8
T3 T6 T9
C
C
C
C
1. Re co rd time andlo cat ion.3. Re co rd scale fact orus in g b lackbo dycali brat io n t ar get .5. Measur e tempe rat ur e o feach gridbo x (d id no tus e cent er g rid fo rwat er si tes)
boxe s con tain ing
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Data CollectionIn the Field
Measured the temperature of thecanopy using a handheld thermal gunand a bucket truck.
Measurement Pattern (example):
Location: 226W(truck is on theWest side ofTree 226)
Column 1: Full CanopyColumn 2: Mixed CanopyColumn 3: Soil/ShadeColumn 4: Mixed CanopyColumn 5: Full Canopy
1 2 3 4 5
1
1
1
1
2
2
2
2
3
3
3
3
4
4
4
4
5
5
5
5
22
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AnalysisGeneral Model
MASTER
L
L
(1-)
L
L0= radiance emittedby the atmosphere
Lg = radiance that
reaches surface fromsun
LBB = radiance of
blackbody at sametemperature as surface
= emissivity of
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AnalysisGetting radiance from surface
Atmospheric Correction(MODTRAN 4)
Lg from MODTRAN 4
MASTER
L
L
(1-)
L
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AnalysisGetting temperatures
T = temperature in Kelvin,
= wavelength of the band center in meters
h = Plancks constant (6.62606810-34m2kg/s)
c = speed of light (299792458 m/s)
k= Boltzmanns constant (1.38065031023 m2 kg/s2 /K)
LBB= radiance in W/m2/sr/m
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Analysis
Table 1. Raw data collected in the field on 7/22/2009 usinga handheld thermal gun. Time: Universal Coordinated
Time (UTC). TIR: scale factor for calibration of thermal gun
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Analysis
Table 3. Scale factor applied to Ctemperatures and then converted to Kelvin(+273.15). Algae grids removed. Averages andstandard deviation for each calibration site and
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Analysis
Plot of average calibration temperatures for each site at two
different times. Linear trendline plotted to approximate change intemperature over time (assumed linear change).
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AnalysisCalculating Temperatures from MASTER data
Note: Peak em it tedwavel engt h for Eart hfal ls in to Band 42.
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AnalysisCalculating Temperatures from MASTER data
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Analysis
CalibratedTemperatures appearto be reasonablebased on the fieldmeasurements (pixeltemperature is aweighted average ofsoil and canopy
Temperature Image of
From Field Measurements
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AnalysisResults: Calibrated Temperatures
CalibratedTemperatures
of Almond
Difference
AgainstUncalibratedTemperatures
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Analysis
-3
0
10
Ai r Temp. Pi xel Tem p.Ai r Temp. at Time ofFl igh t: 304. 82 K (fr omBel ri dge Sta ti on )
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Limitations
vField data coll ected on 7/2 2,MASTE R da ta on 7 /24vLimi ted ca nop y t emperatur e
mea su remen ts fo r vali dati onpurposesvPossi ble error in atm osp her iccorrecti onvCali br ati on li ne fr om only 4points
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Conclusion
vCalibrationvCa li br ation wi th fi el d measur ementsis requ ired for accurate canopytemper atu resvMany fa ctors aff ec t th e re su lt sinc ludi ng: a tmosph er ic effe cts,pe rcent c anop y c ove r ver sus per centsha ded and pe rcent sunny soil ,em issi vi tie s, geom et ry of th e c rops,sun a ngle , sen sor loc ati on/ angl e, et c.
vResul tsvThr ee of t he fou r fie ld s had pi xeltemper atu res less tha n a ir
h h
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Further Research
vImpr ove m odels fo r at mo sph er e andchar act eri st ics o f sur facevStud ied a mo del de si gned fo rorang e groves that rep ort edsi gni fi cant accur acy , but lack ofvalues fo r inp ut p ar amet ers andpo ss ib le inap pli cab il it y cause d itto fai lvApp ly unmi xi ng result s (app roxi mat epe rcent ag e of co mpo nen ts in e ach pix el )
vAcqu ir e mo re fi eld dat a fo r imp rov edcali br at ion and mo del vali dati on
A k l d t &
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Acknowledgements &References
Thanks to Shawn & Ni ck, and th e re st ofthe ET grou p for a ll the ir he lp andadv ice! Th anks to ev eryon e who ma deSARP possible !MASTER Wo rk sho p Ha ndboo k, 200 9, Cent ro Nac iona l deAl ta Tecnolo gaA Phy sic al Model fo r Inter pre ting t he La nd S urfa ceTemper atu re Obta ine d by Remo te Senso rs overIn complete C anopies, Vice nt e Ca sell es, Jo se A . So bri no ,a nd C esa r C o l l
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Questions?