Presentation on theme: "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."— Presentation transcript:
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 Band of CO 2.
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
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.
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)
Requirements for Higher Accuracy Good Laboratory Techniques Better Spectral Line Shapes Better Ways to Extract Information from Spectra
Better Spectral Line Shapes Faster, more accurate Voigt profile Dicke narrowing Line mixing Speed Dependence
Better Analysis Techniques Multispectrum technique More physics input Van der Waals approximation Polymers Collision Induced Absorption