EGU25-11015, updated on 15 Mar 2025
https://doi.org/10.5194/egusphere-egu25-11015
EGU General Assembly 2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
Poster | Tuesday, 29 Apr, 16:15–18:00 (CEST), Display time Tuesday, 29 Apr, 14:00–18:00
 
Hall X5, X5.109
Observations of the vertical water vapor distribution and the downward, broadband thermal-infrared irradiance at the ground in the Central Arctic during MOSAiC
Clara Seidel1, Dietrich Althausen1, Albert Ansmann1, Manfred Wendisch2, Hannes Griesche1, Martin Radenz1, Julian Hofer1, Sandro Dahlke3, Marion Maturilli3, Andreas Walbröl4, Holger Baars1, and Ronny Engelmann1
Clara Seidel et al.
  • 1Leibniz Institute for Tropospheric Reearch, Leipzig, Germany (seidelc@tropos.de)
  • 2Leipzig University, Institute for Meteorology, Leipzig, Germany
  • 3Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Potsdam, Germany
  • 4University of Cologne, Cologne, Germany

For the first time, measurements of high-resolution water vapor profiles are available for the central Arctic winter North of 85°N. The measurements were conducted with the Raman lidar PollyXT during the MOSAiC-campaign. Using those observations, the impact of the vertical distribution of tropospheric water vapor on the cloud-free downward, broadband thermal-infrared irradiance (FTIR) was quantified.

Values of the integrated water vapor (IWV) were determined from the lidar-derived vertical water vapor profiles up to the tropopause region and correlated to the FTIR at the surface. Colocated radiosonde measurements were used to consider the influence of the temperature of the vertically distributed water vapor on this correlation with means of a water-vapor-weighted mean temperature (representative temperature of the water vapor distribution).

In the study, seven measurement cases of several hours duration were examined representing slowly changing air masses. Furthermore, 53 rather short-term (10 minutes) measurement cases were investigated. The temporal evolution of the slowly changing air masses revealed a linear relationship between FTIR and IWV with slopes between 7.17 and 12.95 W kg−1 and a coefficient of determination larger than 0.95 for most of the selected cases. A dependence of the slopes and ordinate-intercepts on the water-vapor-weighted mean temperature was found with smaller ordinate-intercepts at lower temperatures. A linear relationship was found between the water-vapor-weighted mean temperature and the temperature determined with the Stefan-Boltzmann law from FTIR. The analysis of 53 independent short-term observations of different air masses confirmed the linear relationship between FTIR and IWV at wintertime cloud-free conditions in the Arctic with a coefficient of determination of 0.75 and a slope of 19.95 W kg−1.

The evaluations of the profile measurements showed a clear influence of the temperatures of the water vapor along its profile on the FTIR at the surface and the importance of the vertical water vapor and temperature distribution for radiation investigations at the surface.

How to cite: Seidel, C., Althausen, D., Ansmann, A., Wendisch, M., Griesche, H., Radenz, M., Hofer, J., Dahlke, S., Maturilli, M., Walbröl, A., Baars, H., and Engelmann, R.: Observations of the vertical water vapor distribution and the downward, broadband thermal-infrared irradiance at the ground in the Central Arctic during MOSAiC, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11015, https://doi.org/10.5194/egusphere-egu25-11015, 2025.