The Effect of Line Mixing on Atmospheric Brightness Temperatures Near 15 μm

Rotational collisional narrowing, or line mixing, has recently been detected in the Q-branch spectra of two π − Σ bands of CO2 near 2000 cm−1 for both self- and N2-broadening [1,2]. The observed line mixing, which is caused by rotationally inelastic collisions that produce interference effects among overlapping lines during the absorption process [3,4] was found to alter absorption coefficients by as much as 65% in the wings of these Q-branches. This paper considers the influence of Q-branch mixing on atmospheric radiative transfer near the strong ν2 Q branch of CO2 at 15 μm.