Analysis of Climate-Relevant Gas Absorption Properties from AWARE and Other ARM Spectral Measurements
Authors
Eli Jay Mlawer — Atmospheric and Environmental Research, Inc.
Vivienne Helen Payne — Jet Propulsion Laboratory/California Institute of Technology
David D. Turner — NOAA- Global Systems Laboratory
Maria Paola Cadeddu — Argonne National Laboratory
Rick Pernak — Atmospheric and Environmental Research, Inc.
Daniel Feldman — Lawrence Berkeley National Laboratory
Matt Alvarado — Atmospheric and Environmental Research, Inc.
Description
The main objective of our project is to use measurements from the Atmospheric Emitted Radiance Interferometer (AERI) deployed at the ARM West Antarctic Radiation Experiment (AWARE) and other ARM sites to improve our knowledge of uncertain infrared spectroscopic parameters of importance to climate, remote sensing, and data assimilation. A primary focus will be the water vapor continuum in the ‘atmospheric window’ (800-1200 cm-1; 8.3-12.5 microns), a key radiative process with respect to water vapor feedback in response to anthropogenic climate change. Continuum absorption coefficients in the widely used MT_CKD continuum model were derived more than a decade ago by an analysis of AERI measurements for conditions with a limited range of PWV and temperature values, thereby not permitting a clear delineation of the foreign and self continua, nor any determination of the self continuum temperature dependence. In this project we are performing a new, comprehensive analysis of all aspects of the water vapor continuum in the atmospheric window -- the self continuum, the foreign continuum, and the self continuum temperature dependence, all resolved spectrally. Our study will use AERI measurements from ARM sites spanning a wide range of precipitable water vapor (PWV) and temperature conditions, thereby allowing the determination of all window continuum parameters. In addition, we will exploit the low PWV values associated with the AWARE AERI measurements to analyze and improve spectroscopic parameters in the water vapor fundamental band (1200-2000 cm-1), a key spectral region for remote sensing and assimilation of H2O, and to improve methane spectroscopic parameters in its neighboring absorption band, which are of critical importance to the IR remote sensing of and the radiative forcing due to CH4.
The first step in our project, which is in its early stages, is to use microwave measurements from numerous ARM sites to derive accurate spectroscopic parameters for water vapor in the microwave. The accuracy of these parameters impacts the accuracy of the water vapor fields in ARM products such as MWRRET and AERIoe, which will be used in our planned infrared analyses. This poster will provide results from these microwave analyses.
