Project C01:
Large scale variations of water vapour and ice supersaturated regions

Brief Summary

Water vapor (H₂O) in the upper troposphere and lower stratosphere (UTLS) is a key player for global radiation and surface climate (Riese et al., 2012). The processes which determine the H₂O concentration in the UTLS region are manifold and encompass large scale transport through the tropopause region as well as small scale processes like convection. Furthermore, its concentration is directly linked to the so-called ice-supersaturated regions (ISSRs, e.g. Gierens et al., 1999) that occur frequently in the mid-latitudes as well as the tropical tropopause regions (Krämer et al., 2020; Petzold et al., 2019). ISSRs are potential formation regions of cirrus clouds, which regulate the exchange of H₂O between the UT and the LS and, in addition, also have an impact on the Earth’s radiation balance (Boucher et al., 2013). Many measurements indicate that ISSRs with embedded cirrus clouds and the tropopause are closely related (Gettelman et al., 2011; Spichtinger et al., 2003). The main goal of this project is to investigate the large scale three-dimensional structure of ISSRs and cirrus clouds from the tropical to the boreal and austral mid and high latitude tropopause regions as well as the related transport pathways of water vapor.

The following central questions will be addressed in this project:

• What is the global temporal and spatial distribution of ISSRs?
• What is the common lifecycle of ISSRs and cirrus clouds, and how do they interact?
• What is the strength of the inter annual variability and the trend of the UTLS H₂O distribution caused by ISSR properties?
• What are the large scale transport pathways from the tropical (e.g. Asian monsoon) into the extratropical lower stratosphere (exLS)
• How is the amount of transported H₂O influenced by cirrus clouds and the ice saturation ratio?

Petzold, A., P. Neis, M. Rütimann, S. Rohs, F. Berkes, H. G. J. Smit, M. Krämer, N. Spelten, P. Spichtinger, P. Nedelec, and A. Wahner (2019): Ice-supersaturated air masses in the northern mid-latitudes from regular in-situ observations by passenger aircraft: vertical distribution, seasonality and tropospheric fingerprint. Atmos. Chem. Phys. Discuss. 2019, 1–29. doi: 10.5194/acp-2019-735.

Boucher, O., D. Randall, P. Artaxo, C. Bretherton, G. Feingold, P. Forster, V.-M.-. Kerminen, Y. Kondo, H. Liao, U. Lohmann, P. Rasch, S. Satheesh, et al. (2013): Clouds and aerosols. Climate Change 2013 the Physical Science Basis: Working Group I Contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change 9781107057, 571–658. doi: 10.1017/CBO9781107415324.016.

Riese, M., F. Ploeger, A. Rap, B. Vogel, P. Konopka, M. Dameris, and P. Forster (2012): Impact of uncertainties in atmospheric mixing on simulated UTLS composition and related radiative effects. Journal of Geophysical Research Atmospheres 117 (16), 1–10. doi: 10.1029/2012JD017751.

Gettelman, A., P. Hoor, L. L. Pan, W. J. Randel, M. I. Hegglin, and T. Birner (2011): The extratropical upper troposphere and lower stratosphere. Reviews of Geophysics 49 (3), RG3003. doi: 10.1029/2011RG000355.

Spichtinger, P., K. Gierens, and W. Read (2003): The global distribution of ice-supersaturated regions as seen by the Microwave Limb Sounder. Quarterly Journal of the Royal Meteorological Society 129 (595), 3391–3410. doi: 10.1256/qj.02.141.

Members

Publications

Köhler, D., P. Reutter, and P. Spichtinger (2024): Relative humidity over ice as a key variable for Northern Hemisphere midlatitude tropopause inversion layers. Atmospheric Chemistry and Physics 24 (17), 10055–10072. doi: 10.5194/acp-24-10055-2024.

Rolf, C., S. Rohs, H. G. Smit, M. Krämer, Z. Bozóki, S. Hofmann, H. Franke, R. Maser, P. Hoor, and A. Petzold (2024): Evaluation of compact hygrometers for continuous airborne measurements. Meteorologische Zeitschrift 33 (1), 15–34. doi: 10.1127/metz/2023/1187.

Groß, S., T. Jurkat-Witschas, Q. Li, M. Wirth, B. Urbanek, M. Krämer, R. Weigel, and C. Voigt (2023): Investigating an indirect aviation effect on mid-latitude cirrus clouds – linking lidar-derived optical properties to in situ measurements. Atmospheric Chemistry and Physics 23 (14), 8369–8381. doi: https://doi.org/10.5194/acp-23-8369-2023.

Konopka, P., C. Rolf, M. von Hobe, S. M. Khaykin, B. Clouser, E. Moyer, F. Ravegnani, F. D’Amato, S. Viciani, N. Spelten, A. Afchine, M. Krämer, F. Stroh, and F. Ploeger (2023): The dehydration carousel of stratospheric water vapor in the Asian summer monsoon anticyclone. Atmospheric Chemistry and Physics 23 (20), 12935–12947. doi: https://doi.org/10.5194/acp-23-12935-2023.