joel kuszmaul henrique momm greg easson the university of mississippi

The University of Mississippi Geoinformatics CenterNASA MRC RPC – 11 July 2007

Rapid Prototyping of NASA Next Generation Sensors

for the SERVIR System of Fire Detection in Mesoamerica

Joel KuszmaulHenrique Momm

Greg Easson

The University of Mississippi

Collaborators: Dan Irwin, NASA-MSFC Tim Gubbels, SSAI-Goddard Bob Ryan, SSAI-Stennis


Objectives

• We do not seek to validate or evaluate the MODIS active fire detection algorithm

• This has been done by other scientists

• We seek to compare results from MODIS to results from VIIRS with the goal of identifying issues of active fire detection


MODIS Active Fire Product (SERVIR)

Fires in Mesoamerica


PIXEL VALUE

MEANING

0 not processed –missing data (black)

2 not processed – other reason (black)

3 water (blue)

4 Cloud (purple)

5 No fire (gray)

6 Unknown (black)

7 Low-confidence fire (orange)

8 Nominal confidence fire (yellow)

9 High confidence fire (red)

MODIS Active Fire Product (MOD14) Production Code, Version 4.3.2


The Kappa Statistic• Useful for assessing agreement

between two sets of classification• Corrects for chance agreement• An improvement on the proportion of

correct classification (simplest measure of agreement)

• Calculated in the general case as:

2..21..1

2..21..122111

ˆpppp

pppppp

= 0 chance agreement < 0 worse than chance > 0 better than chance


MODIS FIRE ALGORITHM

Channel Number

Central Wavelengh

(µm)Purpose

1 0.65 Sun glint and coastal false alarm rejection

2 0.86Bright surface, sun glint, and coastal false alarm rejection; cloud masking

7 2.10 Sun glint and coastal false alarm rejection

21 4.00 High-range channel for active fire detection

22 4.00 Low-range channel for active fire detection

31 11.00 Active fire detection, cloud masking

32 12.00 Cloud masking

Giglio et al (2003)


Comparison between MODIS and VIIRS spectral and spatial resolution

Spectral Bands Spectral Range (um) Nadir HDR (m) Spectral Bands Spectral Range (um) Nadir HDR (m)M1 0.402-0422 750 8 0.405-0.420 1000M2 0.436-0.454 750 9 0.438-0.448 1000

3 0.459-0.479 50010 0.483-0.493 10004 0.545-0.565 500

12 0.546-0.556 1000I1 0.600-0.680 375 1 0.620-0.670 250

13 0.662-0.672 100014 0.673-0.683 1000

M6 0.739-0.754 750 15 0.743-0.753 1000I2 0.846-0.885 375 2 0.841-0.876 250

M7 0.846-0.885 750 16 0.862-0.877 1000M8 1.230-1.250 750 5 1.230-1.250 500M9 1.371-1.386 750 26 1.360-1.390 1000I3 1.580-1.640 375

M10 1.580-1.640 750M11 2.225-2.275 750 7 2.105-2.155 500

I4 3.550-3.930 250M12 3.660-3.840 750

21 3.929-3.989 100022 3.929-3.989 100023 4.020-4.080 1000

M14 8.400-8.700 750 29 8.400-8.700 1000M15 10.263-11.263 750 31 10.780-11.280 1000

31 10.780-11.280 100032 11.770-12.270 1000

M16 11.538-12.488 750 32 11.770-12.270 1000

M13 3.973-4.128 750

I5 10.500-12.400 375

6 1.628-1.652 500

20 3.660-3.840 1000

M4 0.545-0.565 750

M5 0.662-0.682 750

VIIRS MODIS

M3 0.478-0.498 750


Saturation Differences

Channel 22 (331K)

Channel 21 (500K)

MODIS VIIRS

Channel 31 (400K – 340K)

M-13 (634K)

M-15 (343K)

TERRA AQUA


Study Site


Date Selection

• Criteria for the selection of dates

– Guatemala has to be covered – entirely if possible

– Low cloud coverage – as little as possible

– Lots of fires – Comparison with SERVIR online data

– Availability of imagery with higher spectral resolution for validation

– Availability of the required data: Level 1B and Geolocation files (MOD021KM and MOD03)


Available auxiliary datasets

April 30, 2003

L71019049_04920030430L71019048_04820030430AST_L1B_00304302003163436_20061101193535_8916AST_L1B_00304302003163444_20061101193425_8130AST_L1B_00304302003163453_20061101193325_7631AST_L1B_00304302003163502_20061101193325_7629AST_L1B_00304302003163511_20061101193535_8914AST_L1B_00304302003163520_20061101193535_8908AST_L1B_00304302003163529_20061101193425_8128AST_L1B_00304302003163538_20061101193535_8903AST_L1B_00304302003163546_20061101193535_8899AST_L1B_00304302003163555_20061101193545_9006

April 28, 2003L71021049_04920030428L71021048_04820030428

April 21, 2003

L71020050_05020030421L71020049_04920030421L71020048_04820030421AST_L1B_00304212003164104_20061101192514_4525AST_L1B_00304212003164113_20061101192734_5672AST_L1B_00304212003164121_20061101192614_4850AST_L1B_00304212003164130_20061101192724_5586AST_L1B_00304212003164139_20061101192724_5582AST_L1B_00304212003164148_20061101192724_5575AST_L1B_00304212003164157_20061101192814_5958AST_L1B_00304212003164206_20061101192724_5589

March 20, 2003L71020048_04820030320L71020049_04920030320


Comparing MODIS- and VIIRS-based Detection Tools

• 8 MODIS fire products (one for each sensor, Terra and Aqua, on each of the four study days)

• 16 simulated VIIRS fire products (with two simulated VIIRS products for every one MODIS product due to the two different errors models)


Comparing MODIS- and VIIRS-based Detection Tools (continued)

5 7 8 95 594467 2 170 157 0 0 0 08 7 0 50 19 28 0 28 227

MODIS

VII

RS

The error matrix result comparing the MODIS andsimulated VIIRS fire products for March 20, 2003,using the Terra sensor data and the extended error modelfor the simulated VIIRS data.

Overall Accuracy: 0.999578148Kappa: 0.6989



0.7371

0.7641

0.70110.6900

0.5434

0.6988

0.8791

0.7222

0.6686

0.7187

0.63570.6219

0.4735

0.6331

0.7945

0.6758

0.7028

0.7414

0.66840.6560

0.5084

0.6660

0.8368

0.6990

0.4500

0.5000

0.5500

0.6000

0.6500

0.7000

0.7500

0.8000

0.8500

0.9000

Results from the overall kappa calculations for the case of the point source error model



Overall results comparison for the ability to detect fires using the four different definitions of fires

DAY TERRA AQUA DAY TERRA AQUA

March 20, 2003 0.7028 0.7414 March 20, 2003 0.7351 0.7869April 21, 2003 0.6684 0.6560 April 21, 2003 0.6920 0.6810April 28, 2003 0.5085 0.6660 April 28, 2003 0.5215 0.7014April 30, 2003 0.7335 0.6990 April 30, 2003 0.7503 0.7230

DAY TERRA AQUA DAY TERRA AQUAMarch 20, 2003 0.7369 0.7893 March 20, 2003 0.9134 0.9145April 21, 2003 0.6921 0.6811 April 21, 2003 0.8677 0.8075April 28, 2003 0.5220 0.7022 April 28, 2003 0.6922 0.8291April 30, 2003 0.7524 0.7238 April 30, 2003 0.9182 0.8326

Overall Low-confidence and higher

Nominal-confidence and higher High-confidence


Low and Nominal Confidence Fires

• Nominal confidence fires found only 20% as often using VIIRS

• Low confidence fires not found at all


Comparing Detection Tools Using Validation Data Sets: Results from the Aster Imagery

Fire location and the 25 nearest MODIS pixelscollected to investigate agreement with field data


MODIS - TERRA

0.0000

0.0500

0.1000

0.1500

0.2000

0.2500

0.3000

0.3500

0 10 20 30 40 50 60 70 80 90 100

ASTER Threshold

Kap

pa

Sta

tist

ic

April, 21 2003 April, 30 2003

0.0000

0.1000

0.2000

0.3000

0.4000

0.5000

0.6000

0.7000

0.8000

0.9000

1.0000

0 10 20 30 40 50 60 70 80 90 100

ASTER Threshold

Pro

bab

ilit

y (O

mis

sion

Err

or)

MODIS - TERRA

0.0000

0.0005

0.0010

0.0015

0.0020

0.0025

0.0030

0.0035

0 10 20 30 40 50 60 70 80 90 100

ASTER Threshold

Pro

bab

ilit

y (C

omm

issi

on E

rror

)

VIIRS - TERRA

0.0000

0.0200

0.0400

0.0600

0.0800

0.1000

0.1200

0.1400

0.1600

0 10 20 30 40 50 60 70 80 90 100

ASTER Threshold

Kap

pa S

tati

stic

April, 21 2003 April, 30 2003

VIIRS - TERRA

0.0000

0.1000

0.2000

0.3000

0.4000

0.5000

0.6000

0.7000

0.8000

0.9000

1.0000

0 10 20 30 40 50 60 70 80 90 100

ASTER Threshold

VIIRS - TERRA

0.0000

0.0002

0.0004

0.0006

0.0008

0.0010

0.0012

0.0014

0 10 20 30 40 50 60 70 80 90 100

ASTER Threshold

Pro

babi

lity

(Com

mis

sion

Err

or)


Comparing Detection Tools Using Validation Data Sets: Results from the Landsat Imagery

Examples of Landsat false color composite images showing active fires in Guatemala

Two independent image analysts


Comparing Detection Tools Using Validation Data Sets: Results from the Landsat Imagery (continued)

Comparison of both large and small fires identified inLandsat-7 imagery and fires detected by the MODIS- and VIIRS-based DST

Small Fires OverallSensor No. Found Fires No. Found Fires No. Found Fires No. Found Fires No. Found Fires Accuracy

MODIS:Aqua 0 1 6 25 0 2 0 12 6 40 15.00%VIIRS:Aqua 0 1 0 25 0 2 7 12 7 40 17.50%

MODIS:Terra 1 1 14 25 1 2 2 12 18 40 45.00%VIIRS:Terra 0 1 11 25 0 2 9 12 20 40 50.00%

Large Fires AccuracySensor No. Found Fires No. Found Fires No. Found Fires No. Found Fires No. Found Fires (%)

MODIS:Aqua 0 0 4 14 0 0 0 6 4 20 20.00%VIIRS:Aqua 0 0 0 14 0 0 6 6 6 20 30.00%

MODIS:Terra 0 0 9 14 0 0 3 6 12 20 60.00%VIIRS:Terra 0 0 2 14 0 0 5 6 7 20 35.00%

March 20, 2003 April 21, 2003 April 28, 2003 April 30, 2003 Overall

March 20, 2003 April 21, 2003 April 28, 2003 April 30, 2003 Overall


Summary and Findings

• The highest values were obtained when the MODIS- and VIIRS-based assessments of high confidence fires

• The VIIRS-based fire detection system finds few nominal-confidence fires and no low-confidence fires


Summary and Findings

• Previous researchers had identified the potential difficulty of the proposed VIIRS thermal band (3.95 m) in finding small and low intensity fires. Our results confirm their expectations.

• We recommend a change in the sensor-algorithm combination from what is currently planned.


Questions

joel kuszmaul henrique momm greg easson the university of mississippi

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