MOSAiC-ACA and AFLUX - Arctic airborne campaigns characterizing the exit area of MOSAiC

Two airborne field campaigns focusing on observations of Arctic mixed-phase clouds and boundary layer processes and their role with respect to Arctic amplification have been carried out in spring 2019 and late summer 2020 over the Fram Strait northwest of Svalbard. The latter campaign was closely connected to the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. Comprehensive data sets of the cloudy Arctic atmosphere have been collected by operating remote sensing instruments, insitu probes, instruments for the measurement of turbulent fluxes of energy and momentum, and dropsondes on board the AWI research aircraft Polar 5. In total, 24 flights with 111 flight hours have been performed over open ocean, the marginal sea ice zone, and sea ice. The data sets follow documented methods and quality assurance and are suited for studies on Arctic mixed-phase clouds and their transformation processes, for studies with a focus on Arctic boundary layer processes, and for satellite validation application

Liquid water content measured by the Nevzorov probe during the aircraft ACLOUD campaign in the Arctic

The dataset contains the liquid water content measured by the Nevzorov probe during the Arctic CLoud Observations Using airborne measurements during polar Day (ACLOUD) campaign [Wendisch et al., 2019]. The campaign was carried out as part of the German Transregio 172 project "Arctic Amplification: Climate Relevant Atmospheric and Surface Processes and Feedback Mechanisms (AC)3". The Nevzorov probe was installed on the Polar 6 research aircraft of the Alfred Wegener Institute (AWI, Bremerhaven, Germany). The raw data was averaged over 1 second intervals and processed to compute the liquid water content using the true air speed measured by the 5-hole probe installed at the noseboom of Polar 6. The true air speed values are also included in the dataset. The main uncertainty of the computed values is associated with the estimates of the dry-air output signal which was determined manually right before and after the in-cloud segments of the flight. During the in-cloud segments the dry-air signal is unknown and is obtained by linear interpolation of the before- and after-cloud values. The version of the Nevzorov probe used during the ACLOUD campaign requires manual balancing of the probe which is done by an operator during the flight. Some parts of the data could not be recovered when the balancing was not done on time by an operator. For the majority of clouds the liquid water content values obtained from the LWC and TWC sensors of the Nevzorov probe are in close agreement with each other and with the values obtained from the Cloud Droplet Probe (CDP) of the Physical Meteorology Laboratory (LaMP, CNRS/UBP, Clermont-Ferrand, France) also installed on Polar 6. The ice water content was not computed using the Nevzorov probe due to the small amount of cloud ice in the majority of clouds during the ACLOUD campaign