EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Quantifying development of shallow/warm marine cumulus clouds from geostationary observations

Torsten Seelig1, Felix Müller1, Hartwig Deneke2, and Matthias Tesche1
Torsten Seelig et al.
  • 1University of Leipzig, Leipzig Institute for Meteorology (LIM) , Germany (
  • 2Leibniz Institute for Tropospheric Research (TROPOS), Germany

In our study, we track shallow/warm marine cumulus clouds in the trade wind zone centred around the Canary Islands in August 2015. Tracking was performed in the CLAAS-2 data record (CM SAF CLoud property dAtAset using SEVIRI, [1]) which is based on time-resolved geostationary measurements with the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) aboard Meteosat Second Generation. The retrieval of cloud trajectories allows for the calculation of the cloud lifetime distribution, the horizontal cloud size distribution and to characterize temporal changes in cloud properties. Cloud physical properties are available in the daytime. Filtering for daytime and low-level clouds we found about 65 thousand trajectories. For the considered period and domain, the lifetime distribution follows a power law. Most frequent are clouds which live on a time scale of tens of minutes. In the horizontal cloud size distribution, we detected two intervals following an exponential law but with different scaling. The first interval includes cloud sizes smaller than 30 km2 and the second interval includes cloud sizes equal to or larger than 30 km2 but smaller than 1000 km2. Clouds having a mean horizontal cloud size of approximately 30 km2 are most frequent. Furthermore, we present time series’ of cloud physical properties, as cloud droplet effective radius at cloud top re, cloud optical thickness, cloud water path and cloud droplet number concentration. For comparison of the trajectories, we choose re as a measure. If re reaches a certain value the trajectories have been centred at this specific relative time.

[1] Benas, N., Finkensieper, S., Stengel, M., van Zadelhoff, G.-J., Hanschmann, T., Hollmann, R., Meirink, J. F.: The MSG-SEVIRI-based cloud property data
record CLAAS-2. Earth System Science Data 9(2), 415–434 (2017). DOI 10.5194/essd-9-415-2017

How to cite: Seelig, T., Müller, F., Deneke, H., and Tesche, M.: Quantifying development of shallow/warm marine cumulus clouds from geostationary observations, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10068,, 2021.

Corresponding presentation materials formerly uploaded have been withdrawn.