Level-2LandSurfaceTemperatureandEmissivity

ProductStatus

GlynnHulley,RobertFreepartner,NabinMalakarJetPropulsionLaboratory,CaliforniaIns=tuteofTechnology

(c)2017CaliforniaIns3tuteofTechnology.Governmentsponsorshipacknowledged.ECOSTRESSScienceTeamMee/ng,UCDavis,CA,15-17May2017

Na/onalAeronau/csandSpaceAdministra/on

PrincipalInves;gator:SimonHook,JPLCo-Inves;gators:RickAllen,Univ.ofIdaho;MarthaAnderson,USDAJoshuaFisher,JPL;AndrewFrench,USDAGlynnHulley,JPL;EricWood,PrincetonUniv.Collaborators:ChristopherHain,Univ.Maryland

Outline

1.  Level-2Products2.  Level-2AlgorithmandStatus3.  Band4shiWuncertaintyanalysis4.  GEOS-5FPImplementa/on/Tes/ng/Valida/on5.  Summary

Level-2FlowSchema/c

L1AProducts

L1BProducts

L2Products

PGEmodules

Intermediatedata

Otheragencydata

•  PathRadiance•  TransmiZance•  SkyIrradiance

AtmosphericCorrec/on

TemperatureEmissivitySepara/on

CalibratedSensorRadiances

CloudMasking

MERRA2/NCEP/GEOS5Atmosphere

SurfaceRadianceCalcula/on

CloudMask

Space/Timeinterp.atmosphericfields:•  SurfacePressure•  AirTemperatureProfile•  Rela/veHumidityProfile•  Geopoten/alHeight

L2Products

Geoloca/onParameters

Code:C++Timing:~5minutesforoneECOSTRESSgranule(~25millionpixels)Runconfig:Mul/plerun/meop/ons(cloudthresholds,atmosphericdata,WVSmodel)

•  TotalWaterVapor

L3

L3

**Retrieveonallpixelsregardlessofcloud

L3

SDS Long Name Data type Units Valid Range

Fill Value

Scale Factor

Offset

Group L2 LSTE Data LST Land Surface

Temperature uint16 K 7500-

65535 0 0.02 0.0

QC Quality control for LST and emissivity

uint16 n/a 0-65535 0 n/a n/a

Emis1 Band 1 emissivity uint8 n/a 1-255 0 0.002 0.49 Emis2 Band 2 emissivity uint8 n/a 1-255 0 0.002 0.49 Emis3 Band 3 emissivity uint8 n/a 1-255 0 0.002 0.49 Emis4 Band 4 emissivity uint8 n/a 1-255 0 0.002 0.49 Emis5 Band 5 emissivity uint8 n/a 1-255 0 0.002 0.49 LST_Err Land Surface

Temperature error uint8 K 1-255 0 0.04 0.0

Emis1_Err Band 1 emissivity error

uint16 n/a 0-65535 0 0.0001 0.0

Emis2_Err Band 2 emissivity error

uint16 n/a 0-65535 0 0.0001 0.0

Emis3_Err Band 3 emissivity error

uint16 n/a 0-65535 0 0.0001 0.0

Emis4_Err Band 4 emissivity error

uint16 n/a 0-65535 0 0.0001 0.0

Emis5_Err Band 5 emissivity error

uint16 n/a 0-65535 0 0.0001 0.0

EmisWB Wideband emissivity uint8 n/a 1-255 0 0.002 0.49

ECOSTRESSLevel-2Products

Hulley et al. 2012 (Uncertainty Analysis Study)

LST Uncertainty (K) Surface types

Samples MODTRAN Simulations

3-band TES

5-band TES

Dense vegetation, Water, Ice, Snow

8

660,096

2.19 1.63

Rocks

48 3,960,576

1.44

1.45 Soils

45 3,713,040

0.89

0.91 Sands

10 825,120

1.12

0.99 Total

111 9,158,832

1.49 K

1.13 K

LSTUncertaintyAnalysis

TES5-bandapproachmeets~1KaccuracycapabilityforECOSTRESS(Requirementis2K)

LEVEL-2TASK Comple;onSimulateL1/L2Products(VIIRS,ASTER) 01-31-2016

L2Documenta/on(ATBD,PSD) 02-23-2016

L2CodeconversiontoC++ 07-22-2016

Installa/onofnecessarylibraries,radia/vetransfermodels,Ancillarydata(ASTER)

07-25-2016

Metadata,uncertain/es,cloudmask,errorlogs 07-29-2016

L2codetes/ngonsimulateddata 08-15-2016

BaselineL2PGEwithProcessControlSystem(PCS) 09-30-2016

IncorporateNCEPatmosphericdata(backup)

12-15-2016

ImplementWaterVaporScaling(WVS)Model 1-25-2016

Documenta/on(CloudATBD,ASD,UserGuide) Ongoing

CloudMaskevalua/on/refinement Ongoing

TestandimplementGEOS-5FPatmosphericdata Ongoing

Updatealgorithmcoefficients/dataforband4spectralshiW Ongoing

L2AlgorithmStatus

SpectralResponseFunc/ons(bestes/mateasof8.25.2016)

Band CentralWavelength(µm)

Bandwidth(µm)

1 8.29 0.355

2 8.80 0.309

3 9.20 0.395

4 11.41(10.6) 0.553

5 12.09 0.610

Atmospheric‘windows’

O3H2O

H2OCO2

SRFalgorithmicdependencies:•  Emissivitycalibra/oncurve•  BrightnesstemperatureLUT’s•  RadianceconversionLUT’s•  RTmodelcoefficientfiles•  Uncertaintyes/mates

TransmiZance

SpectralResponseFunc/ons(ExpectedshiW05.2017)

Atmospheric‘windows’

O3H2O

H2O

Band CentralWavelength(µm)

Bandwidth(µm)

1 8.29 0.355

2 8.80 0.309

3 9.20 0.395

4 11.41(10.6) 0.553

5 12.09 0.610

SpectralResponseFunc/ons

SpectralResponseFunc/ons

LST RMSE Surface types

V1*

V2* (band 4 shift)

Graybody (Veg, Water, Snow)

0.555K 0.542K

Barren (sands, soils, rocks)

0.974K 0.958K

Total 0.79K 0.78K

TESAlgorithmperformancewithBand4shiW

•  MODTRANRadianceSimula/ons•  ECOSTRESSTESalgorithm•  GlobalRadiosondeprofiles(SeeBor)•  ASTERspectrallibraryforemissivity

*V1=ECOSTRESSspectralresponsefrombestes/mate08/25/16V2=ECOSTRESSV1withsimulatedband4shiWfrom11.2to10.6micron

NCEPGDAS MERRA-2 GEOS-5FP

Descrip/on Reanalysisfrom1979-present

Reanalysisfrom1979-present

Analysesandforecastsinnearreal-/meusingrecentGEOS-5model

Spa/alResolu/on

1.0degree(~100km)

0.5degree(~50km)

0.25degree(~25km)

TemporalResolu/on

6hourly 6hourly 3hourly

Ver/calResolu/on

26pressurelevels 42pressurelevels 42pressurelevels

Latency Daily 1month Daily

NumericalWeatherPredic/on(NWP)ModelsusedforECOSTRESSAtmosphericcorrec/on

MERRA-2TotalWaterVapor(mm)0.5x0.625deg(~50km)

GEOS5-FPTotalWaterVapor(mm)0.25deg(~25km)

Redwood

TexasGrassland

LST&EValida/onSites(Stage1,‘Tes/ng’)

9%reduc/oninerror

Insitu

HurrianceOdile

30%reduc/oninerror

Insitu

Summary•  ECOSTRESSL2Products:– LandSurfaceTemperature(LST)– SpectralEmissivity(5bands)– BroadbandEmissivity– CloudMask

•  Welldefinedandstrongalgorithmheritage(ASTER/MODIS/VIIRS/MASTER)

•  L2CcodetestedandbaselinedinSDS•  Band4shiWhasnoeffectonL2accuracy•  Usinghigherresolu/onGEOS5-FPresultsin10-30%higheraccuracyofretrievedLST

CloudMaskOutput

•  8-bitproduct

Table3.8bitLevel2CloudMaskProduct.

X Uncalibratedband–dynamicthresholdrequiredpersceneMayoveres/mateovermostlandsurfaces

Carefulconsidera/onoflandsurfaceemissivityrequired

GoogleEarth:08/28/14MASTERLST:08/26/2014

319.2K323.8K

1.  Signatures of vegetation stress are manifested in the LST signal before any visible deterioration of vegetation cover occurs.

2.  The surface moisture state can be deduced directly from the remotely sensed LST.

400m

Theore/calBasis:SurfaceTemperature

⎥⎥⎦

⎤

⎢⎢⎣

⎡−⎟⎟⎠

⎞⎜⎜⎝

⎛=

1exp 25

1

sTccBλλ

λ

EmissivityIrradianceSky gDownwellin

Reflection Surface eTemperatur Brightness Surface)

eTemperatur Surface wavelength=

radiance spectralblackbody :where

=

=

=

=

=

=

↓

λ

λ

λ

ε

ρ

λ

L

(θTT

λ

s

B

AsthetemperatureincreasesthepeakinthePlanckfunc/onshiWstoshorterandshorterwavelengths

⎟⎟⎠

⎞⎜⎜⎝

⎛ −=

↓−

λ

λλλ ε

ρθ LLBTs)(1

0

20

40

60

80

100

Ra

dia

nc

e (

W/m

*m*m

)/1

.0e

6

4 6 8 10 12 14 16 18 20 Wavelength (micrometers)

450K

350K

273.15K

ThermalInfrared(TIR)

LandSurface(‘Skin’)Temperature(LST)

( ))()( 1 θθ λλλ LBT −=

Radiometric(‘Brightness’)Temperature PlanckFunc/on

22

TemperatureEmissivitySepara;on(TES)Algorithm‘ASTERapproach’

EmissivityCalibra/onCurve

T-E separation is under-determined: If have N measurements, always have N+1 unknowns: Radiance Band 1 = T + emissivity1 Radiance Band 2 = T + emissivity2 Radiance Band 3 = T + emissivity3 Radiance Band 4 = T + emissivity4 Radiance Band 5 = T + emissivity5 …………………………. ………………………

0.60

0.65

0.70

0.75

0.80

0.85

0.90

0.95

1.00

1.05

7.5 8.0 8.5 9.0 9.5 10.0 10.5 11.0 11.5 12.0

Emissivity(0

-1)

Wavelength(micrometers)

Emisssivitiesforvarietyofmaterials

GraniteBasaltGrassWaterSandstoneInseptisol

↑↓+⎥⎦⎤

⎢⎣⎡ −+= λλλλλλ εθτθ LLLL surf )1()()( )(TsBLsurf λλ ε=

Itera;velysolveforsurfaceradiance+Temperature/Emissivity