The progress in the MSCCC project can be divided into the following:
(1) Observations of marine stratocumulus clouds (MSC): A novel methodology for retrieving MSC geometrical and thermodynamical properties from satellites was developed and validated against in-situ observations. Using the methodology, I showed that MSC are less likely to breakup when the cloud are decoupled from the ocean surface. This challenges the generally accepted mechanism of transitions between closed and open cells of MSC. The results are published open-access (doi:10.1029/2018GL078122).
Together with a master student that I was advising, the synoptic conditions in which MSC over the north Atlantic ocean are affected by European air pollution were diagnosed. The results demonstrates the co-variability between synoptic conditions and cloud radiative forcing due to anthropogenic air pollution, and allows a long term quantification of the forcing exerted by aerosol-cloud interaction in the region of the north Atlantic ocean. This work was accepted as a successful master project at the University of Leipzig.
(2) Modeling of marine stratocumulus clouds: In order to understand the process level in which global climate models simulate MSC, simulations of cases in which MSC were observed to be affected by anthropogenic aerosols were performed using the ECHAM6-HAM2 global climate model (GCM). The results revealed that cloud cover and cloud properties differ significantly between polluted and clean simulations, and that the highly simplified model parameterization is able to capture the complex physical processes. The results are under preparation for publication.
In addition to the GCM simulations, large eddy simulations (LES) with resolved cloud processes were performed as well. I used a novel approach in which LES simulations are driven by re-analysis data. Initial results show that, for the same governing large scale conditions (i.e. meteorology and sea surface temperature), changes in aerosol concentrations affect the timing of the closed-to-open cells transitions, so that more polluted clouds survive longer before breaking up. This validates the main hypothesis of MSCCC.
(3) In addition to the MSCCC project, I also contributed to collaborative projects led by colleagues. Among those (1) a novel methodology for satellite retrieval of ice particle concentration (doi:10.5194/acp-2018-20) (2) cirrus clouds formation mechanism classification (doi:10.5194/acp-18-6157-2018) (3) characterizing entrainment in GCMs, and (4) response of cloud liquid water path to aerosols and the related cloud radiative effect.
(4) Along the research work, I also took part in teaching bachelor and master students (Dynamic meteorology and Climate dynamics courses), advising a Master project, as well as giving a public lecture on climate related topics. Results of my research were presented in international conferences and scietific meetings.
