Fire Detection with the ATSR2 Sensor

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Fire Detection with the ATSR-2 Sensor

• By Kurt Fischer
• ME 449

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Table of Contents

• 1) Introduction
• 2) Background on thermal radiance
• 3) Background on fire radiance
• 4) How the ATSR senses fires
• 5) Summary

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Introduction

• Objective To provide a concise explanation on
  how the ATSR-2 sensor, on the ERS-2 satellite,
  detects fires.
• Rational This was done in order to achieve a
  better understanding in the interpretation of the
  ATSR data using the Voyager browser program.
• This collection of information was gathered from
  internet research that focused on NASAs remote
  sensing tutorial web site , and the European
  Space Agencys web site concerning the ATSR
  World Fire Atlas.

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Thermal Radiance Background

• Objects of different temperature radiate
  different wavelength bands
• These different bands have different maximum
  relative intensities
• When the temperatures differ by 500C, these
  maximum relative intensities differ by an order
  of magnitude
• This large difference allows fires to standout
  from the background

See http//rst.gsfc.nasa.gov/sect9/sect9_2.html
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Fire Radiance Background

• A fires temperature can range from 400 K to 1000
  K
• The respective maximum relative intensity occurs
  2-5µm
• This gives the optimum wavelength to use in order
  to see the fire
• The channel that is used on the ATSR-2 to detect
  fires is at 3.7µm

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Satellite Sensing of Fires
Here is an example of two signals that would
saturate the sensor

• The satellite first views a pixel (1km2) using
  the channel at 3.7 µm
• It makes a record of the fire when a signal
  saturates the sensor
• The signals intensity must be high enough in
  order for saturation to occur
• Intensity is a function of temperature and area
• Saturation first occurs at around 320 K (given a
  large enough area)
• Must be done at night to avoid solar reflectance
  which would cause artefact signals
• Clouds will block the signal from fires

See http//esapub.esrin.esa.it/eoq/eoq50/arino50.h
tm
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Summary

• Be more specific!!
• Fires can be detected because of their higher
  temperature (400-1000K????) relative to its
  surroundings.
• The high temperature radiates a wavelength band
  with a maximum relative intensity occurring at a
  3-5 um??? unique wavelength.
• The sensor, which is tuned to 3-5 um???, can
  detect fires because the radiance is much greater
  than that of the background.
• The sensor has limitations include
• - solar glare fires can only be detected at
  night occur at night because solar reflectance
  will cause false signals and
• - cities,
• - clouds will block the sensor from seeing the
  fire.
• - non-fire signal ???