Analysis of Water Vapor Absorption in the Far-Infrared and Submillimeter Regions Using Surface Radiometric Measurements From Extremely Dry Locations

Year: 2019

Authors: Mlawer E., Turner DD., Paine SN., Palchetti L., Bianchini G., Payne V. H., Cady-Pereira KE., Pernak RL., Alvarado MJ., Gombos D., Delamere JS., Mlynczak MG., Mast JC.

Autors Affiliation: Atmospher & Environm Res, Lexington, MA 02421 USA; NOAA, Earth Syst Res Lab, Global Syst Div, Boulder, CO USA; Smithsonian Astrophys Observ, Cambridge, MA USA; CNR, Ist Nazl Ott, Sesto Fiorentino, Italy; NASA, Jet Prop Lab, CALTECH, Pasadena, CA USA; Morse Corp, Cambridge, MA USA; Alpenglow Sci, Fairbanks, AK USA; NASA, Langley Res Ctr, Hampton, VA 23665 USA; Sci Syst & Applicat Inc, Hampton, VA USA; Texas A&M Univ, Dept Atmospher Sci, College Stn, TX USA

Abstract: The second Radiative Heating in Underexplored Bands Campaign (RHUBC-II) was conducted in 2009 by the U.S. Department of Energy Atmospheric Radiation Measurement program to improve water vapor spectroscopy in the far-infrared spectral region. RHUBC-II was located in an extremely dry region of Chile to ensure very low opacities in this spectral region. Spectrally resolved measurements by a far-infrared spectrometer and a submillimeter interferometer from RHUBC-II are compared with line-by-line radiative transfer model calculations. Water vapor amounts and temperatures used in the calculations come from collocated radiosondes, with extensive adjustments to correct for issues due to the campaign’s dry conditions and mountainous terrain. A reanalysis is also performed of far-infrared measurements taken at the Atmospheric Radiation Measurement North Slope of Alaska site before and during the first RHUBC campaign. These analyses determine that differences between the measurements and model calculations using existing spectroscopic parameters are significant in the far-infrared and submillimeter regions, leading to the derivation of improved water vapor continuum absorption coefficients and air-broadened widths of 74 water vapor lines. The foreign continuum is increased by more than 50% in part of the far-infrared and the widths of more than 20 lines are changed by more than 10%. The uncertainty in the foreign continuum coefficients is estimated as greater than 20% in some spectral regions, primarily a consequence of the uncertainty in the specification of water vapor. The improved far-infrared spectroscopic parameters have a notable impact on calculated spectral radiances and a modest impact on broadband radiative fluxes and heating rates.


Volume: 124 (14)      Pages from: 8134  to: 8160

More Information: The RHUBC-II campaign was organized as part of the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) program, which is sponsored by the Office of Science, Office of Biological and Environmental Research, Climate and Environmental Sciences Division. RHUBC-II was also supported in part by NASA, the Italian National Research Council, the Smithsonian Institution, and the German Science Foundation (DFG). The authors wish to thank the many members of the ARM program who contributed to the success of the RHUBC-II campaign. Special thanks go to Kim Nitschke and his team for organizing the logistical aspects of the campaign, and Kim and Jim Mather for the roles they played in choosing the site location. We thank Tim Wagner and Dave Tobin for each acting as lead site scientist for part of the campaign, and Alex Carizo for the invaluable role he filled in RHUBC-II operations and interfacing with local personnel and vendors. We also thank the staff at AstroNorte. We thank the NASA FIRST team during RHUBC-II, which included Rich Cageao, Glenn Farnsworth, Mike Wojcik, Jason Swasey, Joe Lee, Erik Syrstad, and Dave Johnson. We thank Bob Knuteson, Hank Revercomb, Dave Tobin, and Joe Taylor for their expertise on AERI spectral calibration and quality control. We would also like to acknowledge the many other people who contributed to the campaign and the collection of the data sets on the campaign: Charles Brinkmann, Troy Culgan, Mike Ryzcek, Julio Marin, Arlette Chacon, Toufic Hawat, Huabai Li, Marcos Diaz, Francesco Castagnoli, Denny Hackel, Ray Garcia, and Rich Coulter. We also thank the many people who shared their expertise with respect to the Atacama region that benefitted our planning for RHUBC-II: Humberto Fuenzalida, Simon Radford, Jose Rutllant, Lyman Page, Anthony Beasley, Monica Rubio, Michel Cure, David Rabanus, and Miguel Gonzalez. We thank three anonymous reviewers for their insightful comments and suggestions. All RHUBC-II radiometric measurements and the temperature and moisture profiles used in the analysis are available at and the ARM RHUBC-II data archive. Work on the study at AER was supported by the U.S. Department of Energy through contracts DE-FG02-90ER61064 and DE-SC0008618 and subcontract 331K203 from the University of Wisconsin, Dr. Turner´s efforts were supported by grant DOE via grant DE-SC0008830 and by NOAA, and Dr. Paine was supported by Smithsonian Institution Endowment Funds and the Smithsonian Astrophysical Observatory. Palchetti and Bianchini were supported by the Italian National Research Council-Earth System Science and Environmental Technologies-Institute of Applied Physics “Nello Carrara.” Work at the Jet Propulsion Laboratory, California Institute of Technology, was carried out under a contract with the National Aeronautics and Space Administration. References herein to any specific commercial product, process or service by trade name, trademark, manufacturer or otherwise does not constitute or imply its endorsement by the United States Government or the Jet Propulsion Laboratory, California Institute of Technology. Support for the FIRST team was provided by the NASA Earth Science Technology Office for the FIRST recalibration effort and the Climate Absolute Radiance and Refractivity Observatory (CLARREO) preformulation project at NASA Langley Research Center for the FIRST field campaign data analyses.
KeyWords: water vapor continuum; far-infrared; submillimeter; radiative fluxes; heating rates; spectroscopy
DOI: 10.1029/2018JD029508

Citations: 24
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