Wednesday, 11 July 2018
Regency A/B/C (Hyatt Regency Vancouver)
Aerosol-cloud-dynamics interactions are suspected to contribute to the currently occurring rapid warming of the Arctic. To retrieve the full vertical extent of marine cloud macro- and microphysical properties the use of cloud radars during ship cruises becomes increasingly frequent. Nevertheless, there are still only a few studies of stabilized cloud radars, which is a necessary requirement to determine also cloud vertical dynamics. In the framework of (AC)³, we investigate aerosol-cloud interactions and the influence of the vertical air motion on the microphysical properties of Arctic clouds to improve the understanding of the mechanisms behind the rapid warming of the Artic. To study the role of clouds in this matter for the first time a stabilized 35-GHz cloud radar of type Mira-35 was deployed on Polarstern during the cruise PS106 in the central Arctic from May 25th to July 21st, 2017. A stabilization platform was used to minimize the influence of the pitch and roll movement of the vessel onto the point of view of the cloud radar. To enable a later correction of the ship’s heave the motion of the vessel was logged with a frequency of 20 Hz and the radar moments were stored at a frequency of 4 Hz. Together with the well-established OCEANET container, carrying continuous measurements of multiwavelength polarization Raman lidar, microwave radiometer, and radiation, the entire vertical cloud and aerosol structure was captured during this two-month cruise. In this conference, we present the heave correction procedure, the overall meteorological conditions during the cruise retrieved by the synergistic Cloudnet algorithm, as well as a comparison to tethered balloon turbulence measurements performed during PS106. In order to estimate the cloud radiative forcing at the Arctic surface, the contrast in the results from radiative transfer calculation using the single-column Rapid Radiative Transfer Model (RRTMG) on the one hand based on lidar and microwave radiometer measurements only and on the other hand also including cloud-radar-retrieved microphysical properties is outlined.
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