Contribution of clouds to radiative diabatic heating and cooling, from synergy of airborne lidar, radar, and imager observations

• Applicants: Professor Dr. Bernhard Mayer; Professor Dr. Markus Rapp; Dr. Tobias Zinner
• Subject Area: Atmospheric Science
• Term: from 2016 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 316834395

• Final Report Year: 2020

Final Report Abstract

The main technical achievement of the project was the development of a downward-looking, pressure- and temperature-controlled version of the spectral visible and near infrared imager specMACS. The passive imager specMACS ideally complements the HALO cloud and aerosol remote sensing configuration consisting of radar, lidar, and passive microwave radiometer. The original purpose was the participation during the NARVAL-2 and NAWDEX campaigns in 2016 ("Next-generation Aircraft Remote sensing for VALidation studies", "North Atlantic Waveguide and Downstream Impact Experiment"). During these first campaigns the instrumentation proved extremely useful, and specMACS was meanwhile also flown during the EUREC4 A Barbados campaign in 2020 (“Elucidating the role of clouds-circulation coupling in climate”). Further operation is scheduled for the HALO campaigns CIRRUS-HL (2021), (AC)3 (2022), and planned for future campaigns (SOUTH, TOOC, ECVAL). After completion of the two original campaigns, the PhD project focussed on spatial distribution of cloud microphysics of convective clouds (cloud geometry, thermodynamic phase, effective radius, and optical thickness). The information gain by adding the imager to the lidar/radar measurements onboard HALO was evaluated. The cloud contribution to diabatic radiative heating and cooling was quantified, by using the synergy of the active and passive remote sensing instrumentation. During this project a new algorithm was developed combining spectral imagery with passive microwave radiometry, lidar profiles, and temperature and pressure profiles from the drop sonde system. The idea, based on a paper from 2013, was to extrapolate the vertical profile information of microwave radiometer and lidar to the wider swath of the specMACS imager, assuming that similar spectra are related to similar profiles. That way a reconstruction of three-dimensional liquid phase cloud macro- and microphysics was provided at unprecedented spatial resolution for the tropical/sub-tropical trade wind cumulus cases observed during NARVAL-2. Radiative heating and cooling by these cloud fields and, in order to bridge the gap to larger scale dynamical effects, the potential vorticity generation by these clouds was derived. The method was published in Atmospheric Measurements Discussions.

Publications

• 2018, The North Atlantic Waveguide and Downstream Impact Experiment, Bull. Amer. Meteor. Soc., 99, , 1607–1637
  Schäfler, A., G. Craig, H. Wernli, P. Arbogast, J.D. Doyle, R. McTaggart-Cowan, J. Methven, G. Rivière, F. Ament, M. Boettcher, M. Bramberger, Q. Cazenave, R. Cotton, S. Crewell, J. Delanoë, A. Dörnbrack, A. Ehrlich, F. Ewald, A. Fix, C.M. Grams, S.L. Gray, H. Grob, S. Groß, M. Hagen, B. Harvey, L. Hirsch, M. Jacob, T. Kölling, H. Konow, C. Lemmerz, O. Lux, L. Magnusson, B. Mayer, M. Mech, R. Moore, J. Pelon, J. Quinting, S. Rahm, M. Rapp, M. Rautenhaus, O. Reitebuch, C.A. Reynolds, H. Sodemann, T. Spengler, G. Vaughan, M. Wendisch, M. Wirth, B. Witschas, K. Wolf, and T. Zinner
  
• 2019, A High-Altitude Long-Range Aircraft Configured as a Cloud Observatory: The NARVAL Expeditions, Bull. Amer. Meteor. Soc., 100, 1061–1077
  Stevens, B., F. Ament, S. Bony, S. Crewell, F. Ewald, S. Gross, A. Hansen, L. Hirsch, M. Jacob, T. Kölling, H. Konow, B. Mayer, M. Wendisch, M. Wirth, K. Wolf, S. Bakan, M. Bauer-Pfundstein, M. Brueck, J. Delanoë, A. Ehrlich, D. Farrell, M. Forde, F. Gödde, H. Grob, M. Hagen, E. Jäkel, F. Jansen, C. Klepp, M. Klingebiel, M. Mech, G. Peters, M. Rapp, A.A. Wing, and T. Zinner
  
• Aircraft-based stereographic reconstruction of 3- D cloud geometry, Atmos. Meas. Tech., 12, 1155–1166
  Kölling, T., Zinner, T., and Mayer, B.
  
• Cloud geometry for passive remote sensing, PhD thesis, Ludwig- Maximilians-Universität München, Faculty of Physics
  Kölling, T.
  
• Synergy of Active- and Passive Remote Sensing: An Approach to Reconstruct Three- Dimensional Cloud Macro- and Microphysics
  Höppler, L., Gödde, F., Gutleben, M., Kölling, T., Mayer, B., and Zinner, T.