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Published byBaby Mash Modified over 9 years ago
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D. Chris Benner and V Malathy Devi College of William and Mary Charles E. Miller, Linda R. Brown and Robert A. Toth Jet Propulsion Laboratory Self- and Air-Broadening, Shifts and Line Mixing in the P- and R-Branches of the 22 0 1- 00 0 0 Band of CO 2.
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CO 2 Remote Sensing Science Drives Improvements in Spectroscopic Data The Orbiting Carbon Observatory (OCO) will obtain space-based observations from which column averaged CO 2 dry air mole fraction (X CO2 ) will be retrieved with a precision of 1 ppm (0.3%) More accurate laboratory spectroscopy is needed for Line positions Line intensities Pressure, Temperature, foreign gas dependent widths & shifts Simulated X CO2
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Present Spectral Databases Do Not Provide Sufficient Accuracy for CO 2 Remote Sensing HITRAN 2004 The HITRAN 2004 CO 2 database was tested with high resolution ground based solar-viewing spectra from Park Falls, Wisconsin (P. Wennberg, Caltech) A better than required 0.1% measurement precision is obtained, although fits using HITRAN 2004 exhibit persistent systematic errors in intensities throughout the band.
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Small Changes in Strengths & Widths Affect CO 2 Retrievals at High Airmass Test Line List A Test Line List B Retrievals for March, April & May 2005 (MAM)
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Requirements for Higher Accuracy Good Laboratory Techniques Better Spectral Line Shapes Better Ways to Extract Information from Spectra
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Better Spectral Line Shapes Faster, more accurate Voigt profile Dicke narrowing Line mixing Speed Dependence
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Better Analysis Techniques Multispectrum technique More physics input Van der Waals approximation Polymers Collision Induced Absorption
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