# Presentation: 649154

## NASA Direct Readout Active Fire and Burn Scar Mapping Products

- Louis Giglio
- Science Systems & Applications, Inc. / University of Maryland
- International EOS/NPP Direct Readout Meeting
- 1 April 2008

## Discussion Topics

- MODIS Active Fire
- NPP/NPOESS VIIRS Active Fire
- MODIS Burned Area

## 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.

## Southeast Australia, 10 Dec. 2006, 03:45 UTC

- MODIS Rapid Response System

## Northern Australia

- 29 August 1999

- TRMM VIRS 0.63 μm channel with active fires in red

## Mean Terra MODIS Fire Radiative Power

- Giglio et al. (2006)

## MODIS Direct Readout Active Fire Status

- Matches “official” MODIS fire detection algorithm (currently Collection 5)
- Developed in the MODIS Rapid Response System
- Initial release ~2003 (Collection 3)
- Refinements planned for Collection 6
- Additional refinements planned for Direct-Readout release

## Direct Readout Implementation

- Code written in C
- Stand alone, “non-ECS” version
- SDP Toolkit, PCFs, run-time environment variables **not required**
- Not a pig
- Fast (~1 minute/granule @ 1 GHz)
- Small memory footprint (< 10 MB)
- Source code available from GSFC DRL
- http://directreadout.sci.gsfc.nasa.gov/

## Planned Refinements

- Optional compact fire location output file
- Algorithm improvements
- Reduce false alarms in problem areas
- Recognize optically thick smoke (vs. cloud)
- Improve detection confidence estimate (again)
- Regional customization
- Suggestions/complaints welcome from DR community

## Regional Customization

- Global algorithm for global application
- Always a balance between omission and commission errors
- Several known independent efforts to date
- SE USA, Australia, SE Asia, Italy, others?
- Standard multi-region version of code planned
- South Africa
- Ocean only (!)
- Continental United States

## Caveat

- “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!)

## 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

## Example Scene: Eastern Cambodia

- Active Fire Mask

- ASTER Bands 8 (2.33 μm),
- 3N (0.82 μm), 1 (0.56 μm)

- 12 km

## ASTER Band 9

- Southern Africa, 17 Aug. 2001

- Grid delineates “edges” of 1-km MODIS pixels.

## Example Simulation Results

- MODIS
- Temperate deciduous rainforest
- Night
- 0° scan angle
- Summer
- No background fires

## NPP/NPOESS Active Fire EDR Current Status (1)

- VIIRS instrument generally in good shape
- Some outstanding issues relevant to fire
- On-board aggregation of saturated M15 pixels (*possibly moot*)
- Band-to-band coregistration

## NPP/NPOESS Active Fire EDR Current Status (2)

- Current code is repackaged Collection 4 MODIS code
- Current product is simply a list of fire locations
- Restricts both science and operational use
- Science Team advocating MODIS-like product
- fire mask (cloud, fire, no observation, etc.)
- FRP
- Bureaucratic hurdles for changing product are substantial
- All parties have good intentions but fire products have extremely low priority – not a true EDR but an ARP
**Solution:** Develop independent code and product for DR and science communities

## Satellite-Based Burned Area Products

- Map spatial extent of post-fire burn scars over a particular time period

## Western USA

## Mato Grosso

- MODIS 1-km Active Fire

- MODIS 500-m Burned Area

- 2004 152-273 h12v10

## “Official” MODIS Burned Area Product

- Roy et al. (2002, 2005) BRDF-based approach
- 500-m, daily resolution
- Production commenced in late 2006
- Under evaluation by Science Team and external collaborators
- Full release as early as summer 2008
- Immediate reprocessing planned
- Computationally demanding
- DR version not yet ready

## The challenge: change detection of Burned Areas

- BRDF Effects

**The challenge: change detection of Burned Areas**

- gaps

- Day of burning

- Persistence of the signal

- D. Roy

## Consistency conceptual scheme

**Consistency conceptual scheme**

**time**

****

- observed

- t

******(t+4|t)**

- 

******(t+4|t)**

- predicted

**first detection**

- Consistency
-  window

- BRDF Inversion window

- D. Roy

## ...looking at one algorithm step:

**Observed Reflectance**

**Predicted Reflectance**

- D. Roy

**Notes:**
Production, first of a kind, multiannual product 

## A closer look at the monthly product...

**A closer look at the monthly product...**

**Tile h17v06 2000306**
**(November 2000)**

- SDS “Burndate”

- 205

- 251

- D. Roy

## A closer look at the monthly product...

**A closer look at the monthly product...**

- SDS “Burndate”

- 205

- 251

- D. Roy

## “Backup” MODIS Burned Area Product

- Modified Giglio et al. (2005) VI time series approach
- 500-m, daily resolution
- Limited production to support multiple projects
- Global Fire Emissions Database
- Stand-alone code in use for several years and should be readily adaptable to DR systems

## band 5 (1.2 m)

- VI57

- band 5 (1.2 m)

- band 7 (2.1 m)

## band 5 (1.2 m)

- VI57

- band 5 (1.2 m)

- band 7 (2.1 m)

- Both magnitude of drop and post-burn level depend on many variables -- fixed thresholds inappropriate.

## Approach

- Use “cleaned” active fire maps to select burned and unburned training samples from temporal composites
- Extract conditional PDFs for burned and unburned pixels
- Assign prior burned probability to each pixel
- Bayesian classifier + supplementary relative threshold tests

## “Backup”

- DAILY ACTIVE FIRE MASKS

- TEMPORAL COMPOSITES

- LAND COVER

- VI*, VI*post
*S**, *t**, *t*f
- IQR*pre, IQR*post

- TRAINING MASK

- TEMPORAL TEXTURE

- SPATIAL PRIORS

- INITIAL CLASSIFICATION

- CONDITIONAL PDFs

- CONTEXTUAL FILTER

- BURN MAP

- “Backup”
- Algorithm

- primary role of active fire map

- change summaries

## Northern Australia, approx. August-October 2001

- Maximum decrease in VI

- Post-decrease VI

- Day of maximum decrease

- Active-fire date

- Change-summary examples:

##  Region growing applied to “cleaned” active fire map to identify burned and unburned training pixels...

-  Region growing applied to “cleaned” active fire map to identify burned and unburned training pixels...

## burned training pixel

- unburned training pixel

## burned

- unburned

- dynamic threshold

- Conditional PDFs

## burned

- unburned

- Conditional PDFs

## Final result: Date of burn for each 500-m grid cell

*Final result:* Date of burn for each 500-m grid cell

## Number of months processed in each tile.

- Algorithm Test Tiles

## Validation using high-resolution burn scar maps manually produced from Landsat imagery.

- Each point represents the fraction of each 10-km grid cell mapped as burned.

- 18 Landsat ETM+ scenes from 2001 and 2002

## Alternate representation:

## 9 Landsat ETM+ scene pairs from 2002

## Current Implementation

- Code written in C
- Stand alone, “non-ECS” version
- SDP Toolkit, PCFs, run-time environment variables **not required**
- Moderate pig
- I/O considerable
- Map one month of one MODIS tile in ~2 hours
- ~300 MB semi-adjustable memory footprint

## Current Input Requirements

- Daily gridded surface (or corrected) reflectance
- Bands 1, 2, 5, and 7
- Terra and/or Aqua MODIS
- Reads MOD09GHK and MODHDFSR directly
- Corrected reflectance ingest partially implemented
- Daily gridded active fire maps
- Preferably Terra + Aqua MODIS
- Other sensors
- Land cover map
- MODIS MOD12Q1 by default but regional even better
- All input data coregistered in  MODIS sinusoidal projection

## Short-Term MODIS Direct Readout Implementation

- Delayed production
- Cumulative burn scar map through day *N* available on day *N *+ ~15
- Comparable quality to the official MODIS burned area product
- Handle “standard” Direct Broadcast input data format(s)
- define “standard” format or formats
- Substantial data staging requirements
- In practice need *M* + 2 months of daily data on disk to generate *M*-month map

## Long-Term MODIS Direct Readout Implementation

- Rapid production
- Cumulative map through day *N* available on day *N*
- Map is refined as additional days are acquired
- Minimal staging requirements
- ~10-day moving archive
- Large reduction in I/O

## Slide 47