Physical Review Letters

To accurately attribute sources and sinks of molecules like CO2, remote sensing missions require line intensities (S) with relative uncertainties ur(S)<0.1%. However, discrepancies in S of ≈1% are common when comparing different experiments, thus limiting their potential impact. Here we report a cavity ring-down spectroscopy multi-instrument comparison which revealed that the hardware used to digitize analog ring-down signals caused variability in spectral integrals which yield S. Our refined approach improved measurement accuracy 25-fold, resulting in ur(S)=0.06%.Received 24 April 2019Revised 6 June 2019DOI:https://doi.org/10.1103/PhysRevLett.123.043001Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasAtomic & molecular collisionsAtomic & molecular structureMolecular spectraPhysical SystemsMoleculesTechniquesOptical absorption spectroscopySpectroscopyAtomic, Molecular & Optical

Twenty-Five-Fold Reduction in Measurement Uncertainty for a Molecular Line Intensity