The MODIS Active Fire and Thermal Anomalies Products Louis Giglio Science Systems & Applications, Inc. / University of Maryland NIMH Bulgaria - EUMETSAT Training Workshop 7-10 September 2009

Topics Background MODIS Sensor Products Distribution Caveats Validation Example Applications and Results

Satellite-Based Active Fire Products Identify where fires are actively burning at time of satellite overpass (and implicitly when they are burning) Possibly provide additional information about fires at time of satellite overpass Intensity, average temperature, instantaneous size, rate of combustion, injection height, etc.

Satellite-Based Burned Area Products Map spatial extent of post-fire burn scars over a particular time period Approximate date of burn Possibly provide additional information about area burned Fire severity, burn severity

Southeast Australia, 10 Dec. 2006, 03:45 UTC MODIS Rapid Response System

Fire Radiative Power

MODIS Instrument (1 of 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 of 2) 36 spectral bands covering 0.4 to 14.4 µm Two 250-m bands Five 500-m bands Twenty nine 1-km bands Enable comprehensive daily evaluation of land, ocean, and atmosphere

MODIS Active-Fire Channels Dedicated 1 km fire bands Channel 21: 3.96 µm, ≈ 500 K saturation Channel 31: 11.0 µm, ≈ 400 K saturation Lower noise, lower quantization error, 1-km multipurpose band Channel 22: 3.96 µm, ≈ 330 K saturation

Fire Detection Approach Look for elevated signal at 4 m; use 11 m channel to help exclude warm, non-fire surfaces Adaptive thresholds based on local statistics so algorithm can be applied globally Use additional tests and channels to help reject false alarms Small convective clouds, sun glint, heterogeneous surfaces, land cover/vegetation boundaries, coastline, desert and other hot/reflective surfaces, urban areas*

Products

Preliminaries MODIS “Collection” MODIS Tile Reprocessing round or version Currently at Collection 5 Collection 6 reprocessing early next year MODIS Tile Global sinusoidal grid

MODIS Tiles

MODIS Fire Products (1 of 3) Active Fire (Level 2 -- native swath) Fire mask QA layer Detailed information about each fire pixel MOD14, MYD14 Active Fire (Level 3 -- tiled, sinusoidal grid) Cumulative fire mask Maximum fire radiative power (FRP) Daily and 8-day summaries MOD14A1, MYD14A1, MOD14A2, MYD14A2

Example 8-Day L3 Fire Product Angola Water Unknown Non-Fire Missing 2000 day 241 Tile h19v10

MODIS Fire Products (2 of 3) Climate Modeling Grid Global, 0.5° Monthly, 8-day MOD14CMH, MYD14CMH MOD14C8H, MYD14C8H Fire Locations ASCII Monthly MCD14ML

MODIS Fire Products (3 of 3) Rapid Response Products Imagery (JPEG) Near-real time active fire locations (ASCII)

Siberia, 22 May 2001

Plume length > 200 km Australia, 4 Dec. 2002

Distribution

https://lpdaac.usgs.gov/lpdaac/get_data

CMG and Fire-Location Products fuoco.geog.umd.edu Login: fire Password: burnt cd modis

Caveats

Product Caveats and Issues Pre-November 2000 data quality Envelope of detectable fires False alarms Fire locations Active fire vs. burned area

Pre-November 2000 Data Quality MWIR channels suffer from crosstalk, poor calibration, “dead” detectors SWIR and TIR channels also affected (but to a lesser extent) Obvious artifacts in many products

Early Terra MODIS Artifacts

Terra Band 21, Post-November 2000 Vietnam 2000311 03:40

Factors Affecting Detection Fire size Fire temperature Biome Season Surface temperature Cloudiness Types of clouds Position of sun Viewing geometry Characteristics of smoke Instrument issues Other

False Alarm Sources Small convective clouds Sun glint Land cover/vegetation boundaries Coastline Desert and other hot/reflective surfaces Heterogeneous surfaces Urban areas*

False Alarms Terra MODIS Shanghai 18 July 2004, 02:45 UTC

Fire-Location Limitations “Fire location”-only products omit useful information ASCII (“text”) files Lack spatial context cloud cover, missing data, water Sometimes inappropriate for research purposes (yet used anyway!)

Active Fire vs. Burned Area Data In general they are not the same: 1 km2 “fire pixel”  1 km2 area burning 1 km2 “fire pixel”  1 km2 area burned

Validation

MODIS Active Fire Detection Validation

MODIS Active Fire Validation (1) Primary method is to use coincident, high resolution ASTER imagery “Advanced Spaceborne Thermal Emission and Reflection Radiometer” Terra only (no Aqua ASTER) 14 high resolution channels 15 m, 30 m, 90 m None ideal for observing fires

MODIS Active Fire Validation (2) Fire mask using ASTER imagery Sometimes degraded by frequent ASTER saturation Fire radiative power retrieval using ASTER Cannot use simple middle-infrared band approach used for MODIS with ASTER Often degraded by frequent ASTER saturation Simulated MODIS imagery Independent burn scar maps Usually not able to evaluate false alarm rate

ASTER Fire Detection Approach Use two reflective bands One sensitive to emissive radiation from fires SWIR band 8 (2.3 m) One insensitive to emissive radiation from fires NIR band 3N (0.86 m) Otherwise highly correlated and sensitive to reflective, non-fire radiation Approach is reasonable for small ASTER pixels, but useless at coarser spatial resolution

Example Scene: Eastern Cambodia ASTER Bands 8 (2.33 µm), 3N (0.82 µm), 1 (0.56 µm) Active Fire Mask 12 km

Example Scene: Eastern Cambodia Fires Clouds Burn Scars Vegetation

ASTER Band 9 Southern Africa, 17 Aug. 2001 Grid delineates “edges” of 1-km MODIS pixels. Southern Africa, 17 Aug. 2001

MODIS Active Fire Detection Validation via ASTER

MODIS Active Fire Detection Validation Post-Fire Burn Scar Maps Coincident 30-m ASTER Imagery de Klerk (2008)

Example Simulation Results MODIS Temperate deciduous rainforest Night 0° scan angle Summer No background fires

Collection 6 Plans

Algorithm Refinements Reduce false alarms in problem areas Recognize optically thick smoke (vs. cloud) Smoldering ratio Approximate state of combustion (smoldering, flaming, mixed) Improve detection confidence estimate Improved land/sea mask* Input data improvements*

Applications and Results

Terra MODIS Monthly Active Fires

Terra MODIS Peak Fire Month Giglio et al. (2006)

Terra MODIS Mean Fire Radiative Power Giglio et al. (2006)

Autocorrelation Giglio et al. (2006)

Aqua Fire Fraction STRONGER WEAKER DIURNAL CYCLE STRONGER Giglio et al. (2006)

Global Fire Emissions Database (GFED)

McCarty et al. (2007)

Plume Heights Mazzoni et al. (2007)

Additional Information MODIS Fire and Thermal Anomalies http://modis-fire.umd.edu/ MODIS Active Fire User’s Guide http://maps.geog.umd.edu/products/MODIS_Fire_Users_Guide_2.3.pdf MODIS Land Rapid Response System http://rapidfire.sci.gsfc.nasa.gov/ WIST (order MODIS land products) https://wist.echo.nasa.gov/~wist/api/imswelcome/