edu.ucar.opensky::articles:21337 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-25T16:04:43.176962 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d74j0hsd https://doi.org/10.5067/AURA/MLS/DATA2005 https Related Dataset #1 MLS/Aura L2 Carbon Monoxide (CO) Mixing Ratio - Version 4 https://doi.org/10.1594/PANGAEA.861730 https Related Dataset #2 Middle atmospheric carbon monoxide above Kiruna, Sweden (67.8° N, 20.4° E), 2008-2015, supplement to: Ryan, Niall J; Palm, Mathias; Raffalski, Uwe; Larsson, Richard; Manney, Gloria; Millán, Luis; Notholt, Justus (2017): Strato-mesospheric carbon monoxide profiles above Kiruna, Sweden (67.8° N, 20.4° E), since 2008. Earth System Science Data, 9(1), 77-89 Assessing the ability to derive rates of polar middle-atmospheric descent using trace gas measurements from remote sensors 2018-02-02T00:00:00Z publication https://n2t.org/ark:/85065/d74j0hsd https://doi.org/10.5194/acp-18-1457-2018 Ryan, N. J. author Kinnison, Douglas E. author García, Rolando R. author Hoffmann, C. G. author Palm, M. author Raffalski, U. author Notholt, J. author UCAR/NCAR - Library publisher We investigate the reliability of using trace gas measurements from remote sensing instruments to infer polar atmospheric descent rates during winter within 46-86 km altitude. Using output from the Specified Dynamics Whole Atmosphere Community Climate Model (SD-WACCM) between 2008 and 2014, tendencies of carbon monoxide (CO) volume mixing ratios (VMRs) are used to assess a common assumption of dominant vertical advection of tracers during polar winter. The results show that dynamical processes other than vertical advection are not negligible, meaning that the transport rates derived from trace gas measurements do not represent the mean descent of the atmosphere. The relative importance of vertical advection is lessened, and exceeded by other processes, during periods directly before and after a sudden stratospheric warming, mainly due to an increase in eddy transport. It was also found that CO chemistry cannot be ignored in the mesosphere due to the night-time layer of OH at approximately 80km altitude. CO VMR profiles from the Kiruna Microwave Radiometer and the Microwave Limb Sounder were compared to SD-WACCM output, and show good agreement on daily and seasonal timescales. SD-WACCM CO profiles are combined with the CO tendencies to estimate errors involved in calculating the mean descent of the atmosphere from remote sensing measurements. The results indicate errors on the same scale as the calculated descent rates, and that the method is prone to a misinterpretation of the direction of air motion. The "true" rate of atmospheric descent is seen to be masked by processes, other than vertical advection, that affect CO. We suggest an alternative definition of the rate calculated using remote sensing measurements: not as the mean descent of the atmosphere, but as an effective rate of vertical transport for the trace gas under observation. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright Author(s) 2018. This work is distributed under the Creative Commons Attribution 4.0 License. None eng geoscientificInformation