CAVIAR Meeting

September 2010

ASSESSMENT OF H2O LINE INTENSITIES

Assessment of H2O Line Intensities

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Assessment of H2O Line Intensities

Accepted: JMS May 2010

“….compared to HITRAN2008 …. our values are higher by about 15% for intensities…”

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HITRAN08 / Oudot

Oudot Example

Average “a” Parameter

HITRAN08 Oudot UCL3000-8000 Err 8000-9200 Err 10000-14000 Err 8000-9200 Err 8000-9200 Err

0.99 0.03 1.17 0.05 0.98 0.06 1.02 0.05 1.06 0.04

CONTINUUM DETECTION

H2O Continuum Detection

• Fit spectral lines to simulation (with no continuum)

a τw + b τg + τaero + c

• a, b, c can vary freely• τaero is obtained from handheld aerosol instrument• c is baseline shift, or continuum absorption

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H2O Continuum Detection

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H2O Continuum Detection

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H2O Continuum Detection

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H2O Continuum Detection

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H2O Continuum Detection (25 cm-1)

H2O Continuum Detection (1 cm-1)

Conclusions• H2O line intensities consistency analysis

– 8000 - 9200 cm-1 spectral region is too weak in HITRAN08 by about 20%– New linelist by Oudot gives underestimation about 3%

• Technique for continuum retrieval is currently being developed but initial results are promising– Revised calibration now available– Look for consistently across a number of days– Sensitivity tests to error in profile (e.g 1% ppmv how does retrieved continuum change)– Refine aerosol contribution

• Compare retrieved continuum to new CAVIAR laboratory measurements

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