IRBLEM Model

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IRBLEM Model

• IRBLEM is a software package for the computation
  of atmospheric effects on band EO systems in the
  marine surface layer.
• IR band (3-12 microns).
• Effects caused by refraction, turbulence, aerosol
  extinction and molecular absorption are
  considered.
• Cumulative effects on point-target detection are
  calculated along propagation paths using
  ray-tracing.
• Runs in MS-DOS
• Software developed by
• Defense Research Establishment Valcartier (DREV),
  Canada
• TNO, Netherlands
• Limited Distribution of Software

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Input Parameters (22)

• Pressure (mbar)
• Air temperature (C)
• Relative humidity ()
• Wind speed (m/s)
• Wind direction (deg)
• Mean wind speed over last 24 hours (m/s)
• Water temperature (C)
• Wave height (m)
• Visibility (km)
• Solar radiation (w/m2)
• Air mass parameter (1-10)
• Precipitation rate (mm/h)
• Precipitation type (0 No weather 1 Rain 2
  Drizzle 3 Snow 4 Fog)

• Neutral drag coefficient CDN(10) abU10N
  this is 'a' 1000
• Neutral drag coefficient " "
  this is 'b' 1000
• Neutral stanton number, CHN(10) 1000
• Neutral dalton number, CEN(10) 1000
• Mean wavelength (um)
• Height of the pressure sensor (m)
• Height of the air temperature sensor (m)
• Height of humidity sensor (m)
• Height of the wind speed sensor (m)

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• Output
• Dozens of output options
• Vertical profiles CN2, optical refractivity,
  aerosol extinction.
• Ray tracing plot
• Image resolution
• Maximum path radiance in the marine surface layer
  as a measure of the background radiation.

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Cape St. George, 19/1519 UTC Sep 98 Case ID 001
Geometrical Sight
Tair 34.5 C Wind 4.1 m/s SST 32.6 C
RH 67.3 P
1003.3
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Cape St. George, 23/1151 UTC Jul 98 Case ID 002
Geometrical Sight
Tair 27.6 C Wind 1.7 m/s SST 26.6
C RH 78.4 P
1012.8
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Cape St. George, 19/1416 UTC Oct 98 Case ID 003
Tair 28.7 C Wind 1.8 m/s SST
30.25 C RH 68.3
P 1009.8
Beginning of Mirage Zone Maximum Inter
Vision Range (MIVR) Geometrical Sight

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CN2 Output from IRBLEM