HR: 0800h
AN: A31B-0309    [Abstracts]
TI: SI Traceable Laboratory Determinations of O2 A-Band Line Parameters for Space-Based Measurements of CO2 and Global Surface Pressure
AU: * Hodges, J T
EM: joseph.hodges@nist.gov
AF: Process Measurements Division, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, United States
AU: Robichaud, D J
EM: djr@its.caltech.edu
AF: Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, United States
AU: Okumura, M
EM: mo@its.caltech.edu
AF: Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, United States
AU: Brown, L R
EM: Linda.R.Brown@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, United States
AU: Miller, C E
EM: charles.e.miller@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, United States
AB: Presently, raw radiance data generated by remote-sensing measurements of the atmosphere must be converted into calibrated radiances using known molecular properties of the atmospheric column. To ensure the integrity and long-term continuity of such retrievals, these calibrations need to be grounded in high-quality intrinsic molecular data with well-defined traceability to the International System of Units (SI). In this context, because the molar fraction of O₂ in the atmosphere is accurately known and essentially time invariant, space-based observations of the O₂ A-band spectrum are critical to many remote-sensing applications. Consequently accurate characterization of this spectrum constitutes a well-defined path for SI traceability in both space- and ground-based atmospheric retrievals of many atmospheric species. An important example includes retrievals of CO₂ columns by orbiting spacecraft, [e.g., NASA's Orbiting Carbon Observatory, (OCO)] in which photon path lengths are to be determined in terms of co-observed O₂ A-band spectra. Similarly, accurate measurements of the O₂ A-band in support of meteorological observations and weather modeling have the potential to determine global surface pressure. These and other applications require low relative uncertainty (≪ 0.5%) and SI traceability in O₂ line parameters such as intensity, transition frequency, pressure-induced frequency shifts and broadening, and other quantities related to line shape and line mixing effects. Here, we present the status of O₂ A-band spectral models and reference line parameters data, and we discuss limitations that motivate additional theoretical and experimental research.
DE: 0350 Pressure, density, and temperature
DE: 0365 Troposphere: composition and chemistry
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting