Self-broadening coefficients and improved line intensities for the v_7 band of ethylene near 10.5 μm, and impact on ethylene retrievals from Jungfraujoch solar spectra

摘要

Relying on high-resolution Fourier transform infrared (FTIR) spectra, the present work involved extensive measurements of individual line intensities and self-broadening coefficients for the v_7 band of ~(12)C_2H_4. The measured self-broadening coefficients exhibit a dependence on both J and K_a. Compared to the corresponding information available in the latest edition of the HITRAN spectroscopic database, the measured line intensities were found to be higher by about 10% for high J lines in the P branch and lower by about 5% for high J lines of the R branch, varying between these two limits roughly linearly with the line positions. The impact of the presently measured line intensities on retrievals of atmospheric ethylene in the 949.0-952.0 cm~(-1) microwindow was evaluated using a subset of ground-based high-resolution FTIR solar spectra recorded at the Jungfraujoch station. The use of HITRAN 2012 with line intensities modified to match the present measurements led to a systematic reduction of the measured total columns of ethylene by -4.1±0.1%.