Spectroscopic improvements providing evidence of formic acid in AERI-LBLRTM validation spectra

The capabilities of new and future high-resolution passive sensors, such as the tropospheric emission spectrometer, are placing a greater demand on the accuracy of line-by-line radiative transfer calculations used directly or indirectly in the retrievals of atmospheric constituents. Presented is a validation case study at the Atmospheric Radiation Measurement Southern Great Plains site on the night of 22 July 2001 that illustrates how recent advancements in both the HITRAN2000 spectral lines and the new MTCKD1.0 continuum reduced residuals between the atmospheric emission radiance interferometer and line-by-line radiative transfer model radiances. These improvements reduce line parameter systematic errors in the forward model allowing for the retrieval of elevated values of formic acid (HCOOH), which has a weak atmospheric signal consisting of only ∼5% of the background downwelling zenith radiation in the ν6 HCOOH spectral region