Retrieval of CO Mixing Ratios From the Atmospheric Emission Spectra of Down-Welling Middle IR Radiance in Oklahoma.
Abstract
CO abundances are retrieved from spectra of atmospheric down-welling radiation measured by the Atmospheric Emitted Radiance Interferometer (AERI) at the Southern Great Plains (SGP) observatory of the Atmospheric Radiation Measurements (ARM) program sponsored by the United States Department of Energy (DOE). These spectra measured every 8 minutes are publicly available for the period between 1997 and the present. The R-branch of the CO fundamental vibration-rotational band between 2135 and 2200 cm-1 is chosen for analysis. Radiative transfer calculations are performed using the k-Compressed Atmospheric Radiative Transfer Algorithm (kCARTA). Atmospheric temperature and water vapor profiles were retrieved from other parts of the AERI spectra using standard software developed by the University of Wisconsin and constrained with SGP Microwave Radiometer total precipitable water retrievals. An a priori constant CO mixing ratio profile is perturbed to minimize the spectral residuals due to CO. A correction for the scattered solar radiance during day-time is applied. Independent measurements of CO boundary layer mixing ratios by the Lawrence Berkeley National Laboratory (LBNL) and free tropospheric CO by the Earth System Research Laboratory (ESRL) of the Global Monitoring Division (GMD) , NOAA provide validation for the AERI retrieval technique.
- Publication:
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AGU Spring Meeting Abstracts
- Pub Date:
- May 2009
- Bibcode:
- 2009AGUSM.A11C..06Y
- Keywords:
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- 0360 Radiation: transmission and scattering;
- 0365 Troposphere: composition and chemistry;
- 0394 Instruments and techniques