The purpose of this continued study is to model correctly the concentration of carbon monoxide (CO) in the troposphere of Harrisonburg, VA using an atmospheric modeling software program coupled with an experimental technique. In previous years, multiple raw data sets were collected using a technique known as gas filter correlation radiometry (GFCR) developed at NASA Langley Research Center. This technique utilizes the infrared (IR) radiance of the full moon and combines a ground-based IR data collection system with a blackbody calibration to yield a power value of the radiant stream. The raw data are processed by differencing a radiance stream obtained from the moon as passed through an evacuated cell against a cell containing a fixed concentration of CO. This power value is then compared with those simulated by the atmospheric modeling software HITRAN-PC. HITRAN-PC can simulate the atmosphere of Harrisonburg with a few key changes of input. It can then model the transmittance of the atmosphere, and by applying an algorithm developed in-house, we can correlate this transmission to a corresponding power value. The modeling is performed multiple times with various estimated values of CO, simulating clean and polluted conditions. Once the power value from the data and the power value from the modeling converge, the CO concentration is determined.

Date Published: 1 April 2003
PDF: 7 pages
Proc. SPIE 5073, Thermosense XXV, (1 April 2003); doi: 10.1117/12.489038

Published in SPIE Proceedings Vol. 5073:
Thermosense XXV
K. Elliott Cramer; Xavier P. Maldague, Editor(s)