Validation and comparison of Terra/MODIS active fire detections from INPE and UMd/NASA algorithms

Validation and comparison of Terra/MODIS active fire detections from INPE and UMd/NASA algorithms

LBA EcologyLand Cover – 23

Jeffrey T. Morisette1, Ivan Csiszar2, Louis Giglio2 Wilfrid Schroeder3, Doug Morton2, João Pereira3, Chris Justice2,

1National Aeronautics and Space Administration, Greenbelt, Maryland, USA2Universityof Maryland, College Park, Maryland, USA 3Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis, Brazilia, Brazil

AcknowledgementsAcknowledgements

…special thanks to- Darrel Williams and Peter Griffith and the

LBA-Eco project office- Diane Wickland for including this work into

LBA-Ecology project- Heloisa Miranda and Alexandre Santos for

collaboration on the Thermocouple data- Alberto Setzer for collaboration on

implementing the INPE algorithm- Ruth Defries for continued collaboration on

MODIS-related research- Mike Abrams and Leon Maldonado for

assistance in acquiring ASTER imagery

BackgroundBackground

• IBAMA/PROARCO is charged with monitoring Brazilian fires

• IBAMA posts “Hot Spot” detections from several satellites and algorithms.

• MODIS provides “state of the art” fire detection, but needs to be validated

• Two algorithms on the same sensor’s data and a high resolution sensor on the same satellite create and unique opportunity for this validation study

GoalsGoals

• Assess the accuracy of the 1 km fire product from the Moderate Resolution Imaging Spectroradiometer (MODIS) over the LBA-Study area

• Compare the INPE and UMd algorithm as they relate to the ASTER fire detection

MODIS Instrument (1/2)MODIS Instrument (1/2)

• “Moderate Resolution Imaging Spectroradiometer”

• On board AM-1 (“Terra”) and PM-1 (“Aqua”) polar orbiters– Terra 10:30 & 22:30 local overpass– Aqua 01:30 & 13:30 local overpass

MODIS Instrument (2/2)MODIS Instrument (2/2)

• 36 spectral bands covering 0.4 to 14.4 micrometers– Two 250 m bands– Five 500 m bands– Twenty nine 1 km bands

• Enable comprehensive daily evaluation of land, ocean, and atmosphere

Daily Global BrowseDaily Global Browse

ASTER imageryASTER imagery

ASTER CharacteristicsASTER Characteristics

• “Advanced Spaceborne Thermal Emission and Reflection Radiometer”

• 14 channels– 4 visible and near-IR @ 15 m resolution, 8 bits– 6 SWIR @ 30 m resolution, 8 bits– 5 LWIR @ 90 m resolution,12 bits

• 60 km swath width

Roraima: prescribed burn, 19 JanRoraima: prescribed burn, 19 Jan

ASTER fire mask band 3 and 8 240, 30m pixelsred = band 3, ~22 ha green & blue = band 8

Fire pixels shown in ASTER band3/band8 space

ASTER fire detectionASTER fire detection

Mask water pixels. If 8 < 0.04, a pixel is flagged

as water and excluded from further processing. Identify obvious fire pixels. Pixels for which r > 2 and > 0.2 are considered to be obvious fire pixels and are flagged as such. Identify candidate fire pixels. Pixels for which r > 1 and > 0.1 are considered to be candidate fire pixels.   - contextual tests  

3

8

r

38

3rz 38 z

5.0 Brr

5.088 B

Omission and Commission errorOmission and Commission error

INPE

(no UMDfires detection)

ASTER/MODIS scatter plotASTER/MODIS scatter plot

ASTER fire counts

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LBA Scene 5 INPE

ASTER fire counts

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LBA Scene 5 UMd

UMd Omission errorUMd Omission error

INPE

UMD

ASTER/MODIS scatter plotASTER/MODIS scatter plot

ASTER fire counts

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LBA Scene 12 INPE

ASTER fire counts

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LBA Scene 12 UMd

ASTER fire counts

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Estimated Probabilities for UMd Algorithm

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ASTER fire counts

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Estimated Probabilities for INPE Algorithm

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ASTER fire counts

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Estimated Probabilities for both Algorithms

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Logistic RegressionLogistic Regression

Results from 22 ASTER scenesResults from 22 ASTER scenes

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counts

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MODIS fires

Red = high confidenceBlue = lower confidence

ASTER fire counts

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Matriz de ErrorMatriz de Error

ASTER fire counts

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MODIS - INPENo Fire Fire

ASTER No Fire A BFire Fire C D

A

B

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Error matrixError matrixASTER threshold = 1

MODIS - INPENo Fire Fire sum P(error)

ASTER No Fire 81000 115 81115 0.0014Fire Fire 359 55 414 0.8671

sum 81359 170 81529Overall Accuracy:

P(error) 0.0044 0.6765 0.994

ASTER threshold = 1MODIS - UMdNo Fire Fire sum P(error)

ASTER No Fire 81106 9 81115 0.0001Fire Fire 332 82 414 0.8019

sum 81438 91 81529Overall Accuracy:

P(error) 0.0041 0.0989 0.9958

for any ASTER fire detection

Error matrixError matrixASTER threshold = 1

MODIS - INPENo Fire Fire sum P(error)

ASTER No Fire 81000 115 81115 0.0014Fire Fire 359 55 414 0.8671

sum 81359 170 81529Overall Accuracy:

P(error) 0.0044 0.6765 0.994

For variable fire size

ASTER threshold = 100MODIS - INPENo Fire Fire sum P(error)

ASTER No Fire 81358 149 81507 0.002Fire Fire 1 21 22 0.045

sum 81359 170 81529Overall Accuracy:

P(error) 0.0000 0.8765 0.998

ASTER threshold = 50MODIS - INPENo Fire Fire sum P(error)

ASTER No Fire 81335 130 81465 0.002Fire Fire 24 40 64 0.375

sum 81359 170 81529Overall Accuracy:

P(error) 0.0003 0.7647 0.998

Fires > .0009 km2

Fires > .045 km2

Fires > .090 km2

Error Matrix figuresError Matrix figures…as a function of fire size

P(MODIS "no fire" | ASTER "fire") Chance of Missing a fire or "Ommission Error"

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ASTER threshold or "Fire Size"

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INPE P(MNF|AF)

UMD P(MNF|AF)

ConclusionsConclusions

• ASTER fire detection algorithm is now established

• Comparison of ASTER with MODIS fire products and possible and enlightening

• Both UMd and INPE algorithm do a good job at detecting large fires– INPE has less error for large fires– UMd has less error for small fire & less likely to have

false positives

Questions?Questions?

jeff.morisette@nasa.gov

MODIS: UMd AlgorithmMODIS: UMd Algorithm

• Bands used for fire algorithm“T4”=

– Channel 22: 3.96 µm, ≈ 330 K saturation(lower noise, lower quantization error, but lower saturation)

- or -

– Channel 21: 3.96 µm, ≈ 500 K saturation(used when channel 22 saturates)

“T11” =

– Channel 31: 11.0 µm, ≈ 400 K saturation

MODIS: UMd AlgorithmMODIS: UMd Algorithm

• T4 > 360 Kor• {T4 > mean(T4) + 3xStandardDeviation

or T4 > 330 K}and

• {T4–T11>median(T4-T11) + 3xStandardDeviation(T4-T11) or T4-T11 > 25}

• Then rejected if red and near-infrared channels have reflectance > 30% (to avoid false positives)

From: “The MODIS fire products”, C.O. Justice, L. Giglio et al., Remote Sensing of Environment 83(2002) 244-262.

MODIS: INPE AlgorithmMODIS: INPE Algorithm

channel 20 > 3000andchannel 09 < 3300

Error Matrix figuresError Matrix figures…as a function of fire size

P(MODIS "fire" | ASTER "no fire") = False positive or "commission error"

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ASTER threshold(ASTER fire counts below this threshold are considered non-fires)

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INPE P(MF|ANF)

UMD P(MF|ANF)