Doctoral presentation Number 1

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Deduction of land surface emissivity from
satellite data to improve the atmospheric
correction of IR measurements
Prasanjit Dash
Institute for Meteorology and Climate
Research Forschungszentrum Karlsruhe/University
of Karlsruhe Karlsruhe, Germany. WWW
http//www.fzk.de/imk/imk2/isys
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Contents
Definition Radiometer versus Thermometer
Components of satellite measurements
Underdetermined problem
LST determination methods
Effect of emissivity on LST
Emissivity estimation
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Radiometer versus Thermometer
LST- Radiometric skin temperature corresponding
to the IFOV of the sensor
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Components of satellite measurement
Atmospheric Window
LSE, transmissivity, state of the atmosphere
State of the atmosphere
LST, LSE, transmissivity
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Underdetermined problem
Radiance measurement
2 spectral measurements
R2
R1
3 unknows 1 LST 2 LSEs
LSE 2
LSE 1
LST
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LST determination methods
Dual angle
Split window
Different water vapor absorption due to
spectral range
path length
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Single channel
Simulated satellite measurement
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Split windowDual angle
?1 or path 1
?2 or path 2
TOA R2
TOA R1
Split window2 wavelenghts ?1 and ?2 Dual
angle2 viewing angles path 1 and path 2
WV absorption 1
WV absorption 2
10 - 12 µm window
R2
R1
LSE 2
LSE 1
LST
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Effect of emissivity on LST

• Reduction in magnitude of upwelling surface
  radiance

?

• ? ? 1 ? contribution from reflected radiance

• Anisotropy of emissivity/reflectivity can reduce
  or increase the total radiance from surface
  (Prata 1993)

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Emissivity estimation
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Day / night measurement
Day
Night
Atmosphere
Atmosphere
SUN
R 11
R 3.8
R 11
R 3.8
LSE 2
LSE 1
1 - LSE1
LSE 2
LSE 1
LST day
LST night
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Application of TISI
Integrate ? ?? ? 1 - ?, for channel 3
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Logical Flow
Atmospheric chemistry (CH4 O3 CO2)
(RTM) MODTRAN