HR: 16:15h
AN: A34D-02 INVITED    [Abstracts]
TI: Improved Understanding of Far-Infrared Radiative Processes in the Earth's Atmosphere
AU: * Delamere, J
EM: jdelamer@aer.com
AF: Atmospheric and Environmental Research, Inc., 131 Hartwell Ave, Lexington, MA 02421,
AU: Mlawer, E
EM: emlawer@aer.com
AF: Atmospheric and Environmental Research, Inc., 131 Hartwell Ave, Lexington, MA 02421,
AU: Turner, D
EM: dturner@ssec.wisc.edu
AF: University of Wisconsin Madison, Space Science and Engineering Center 1225 West Dayton Street, Madison, WI 53706,
AU: Green, P
EM: p.green@imperial.ac.uk
AF: Imperial College, Space and Atmospheric Physics Blackett Laboratory Prince Consort Rd, London, SW72BZ, United Kingdom
AU: Clough, S
EM: sclough@aer.com
AF: Atmospheric and Environmental Research, Inc., 131 Hartwell Ave, Lexington, MA 02421,
AU: Payne, V
EM: vpayne@aer.com
AF: Atmospheric and Environmental Research, Inc., 131 Hartwell Ave, Lexington, MA 02421,
AU: Westwater, E
EM: ed.westwater@colorado.edu
AF: University of Colorado Boulder, ECB 245 ECOT-249, Boulder, CO 80309,
AU: Cimini, D
EM: nico.cimini@aquila.infn.it
AF: University of L'Aquila, CETEMPS-Department of Physics Via Vetoio, Coppito-L'Aquila, 67100, Italy
AB: Longwave radiative cooling in the upper troposphere significantly influences Earth's climate. With water vapor dominating this cooling, the spectral regions in which the greatest upper tropospheric cooling occurs are opaque when viewed from the vast majority of surface locations. While the opacity of the lower atmosphere is a formidable obstacle in studying upper tropospheric radiative processes from the surface, a greater obstacle has been the lack of radiometric instrumentation in the most critical spectral region for these processes, the far- infrared (λ > 15 μm). These obstacles have led to a relatively high uncertainty in our knowledge of upper tropospheric radiative processes. In the spring of 2007, the Radiative Heating in Underexplored Bands Campaign (RHUBC) was conducted at the Atmospheric Radiation Measurement Program's (ARM) North Slope of Alaska Climate Research Facility (NSA). The experiment was designed to make detailed observations of the downwelling infrared radiation in the pure rotation (17--100 μm; 100--600 cm^-1) and the 6.7 μm (1350--1850 cm^-1) ν₂ water vapor bands under the extremely dry and cold conditions found at the NSA location. High-spectral-resolution observations were collected by two state-of-the-art Fourier Transform Spectrometers: the ARM AERI-ER (400-- 3000 cm^-1) and the Imperial College TAFTS (80--650 cm^-1). Also, three state-of-the-art microwave radiometers observing emission at 183 GHz were deployed to the NSA site during RHUBC. From these microwave measurements, the total atmospheric water vapor column can be accurately retrieved. With numerous radiosondes launched in conditions with less than 3 mm of total precipitable water vapor, RHUBC provided the opportunity for extensive clear-sky high-spectral-resolution comparisons between model calculations and measurements. This presentation will discuss the infrared radiance measurements, radiative transfer models and specification of the atmospheric state used in these radiative closure studies, as well as the initial efforts to reduce key uncertainties in water vapor spectroscopy. RHUBC is anticipated to improve calculations of polar surface radiative fluxes and mid-to-upper tropospheric radiative cooling, ultimately resulting in improved simulations of Earth's present and future climate.
UR: http://science.arm.gov/rhubc/
DE: 3300 ATMOSPHERIC PROCESSES
DE: 3359 Radiative processes
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting