Dynamic Spectroscopic Measurements of the Temperature and Pressure Cycles in a MOPITT Pressure Modulator Cell

The temperature and pressure cycles inside a pressure modulator cell (PMC) of the type used for gas-correlation radiometry aboard the Measurements of Pollution in the Troposphere (MOPITT) satellite instrument have been determined from dynamic measurements of the spectral line shapes of the R (0) and R (18) transitions in the fundamental vibrational-rotational band of carbon monoxide. The line strengths and linewidths were used to calculate the temperature and pressure, respectively, with a temporal resolution of approximately 200 (mu)s, or 1/100 of a PMC cycle. The results are compared with a thermodynamic box model.