![]() During that time, RV Polarstern drifted with the ice floe from the Arctic Ocean at 82.2°N, 10.1☎ into the Fram Strait at 79.1°N, 2.4°W (Fig. BELUGA was operated on 33 flights resulting in 66 high-resolution profiles up to an average of 1 km height on 14 days. ![]() During the latter part of MOSAiC, the Balloon-bornE moduLar Utility for profilinG the lower Atmosphere 14 (BELUGA) system was deployed from the research camp on the sea ice floe, from 29 June to 27 July 2020. The Research Vessel (RV) Polarstern 12 supported by the research expedition into the central Arctic Ocean 13. Therefore, a vast international effort was undertaken with the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) from September 2019 to October 2020. The essential measurements needed to overcome these issues, particularly above the sea ice, are still sparse. The long-range transport of absorbing particles may play an essential role by causing atmospheric heating or decreasing surface albedo when deposited on snow and ice 11.ĭespite significant efforts and improvements over the past two decades, models still have significant uncertainties that inhibit our ability to understand the impact of ABL processes on Arctic amplification 4. ![]() The magnitude of terrestrial cooling in Arctic mixed-phase clouds depends on cloud microphysical properties 8 that, in turn, are affected by the limited availability of aerosol particles acting as cloud condensation nuclei (CCN) or ice nucleating particles (INP) 9, 10. ![]() However, the cloud-mixed layer is often decoupled from the surface when turbulence is vertically discontinuous 7. Radiative cooling at the cloud top induces entrainment from aloft and turbulent mixing inside the ABL. Capping temperature inversions near the cloud top represent a barrier for the vertical transport of heat, moisture, aerosol, and trace gases between the free troposphere and the ABL. The summertime Arctic ABL above sea ice is often neutrally stratified and dominated by low-level liquid or mixed-phase clouds 6. While the surface albedo and lapse rate feedback are thought to be the main drivers 4, further complex atmospheric boundary layer (ABL) processes are considered to contribute significantly to Arctic warming 5. This accelerated Arctic warming is known as Arctic amplification and it results from local and remote feedback mechanisms in response to global warming 3. Between 19, the Arctic mean air temperature increased three to four times faster than the global mean temperature, depending on the considered southern boundary of the Arctic 2. The Arctic environment has undergone substantial changes over the last decades, including a dramatic loss in sea ice 1. We invite the scientific community for joint analysis and model application of the freely available data on PANGAEA. This publication describes the balloon operations, instruments, and the obtained data set. The profiles feature a high vertical resolution of 0.01 m to 1 m, including measurements below, inside, and above frequently occurring low-level clouds. In total, 66 profile observations were collected during 33 balloon flights from the surface to maximum altitudes of 0.3 to 1.5 km. The in situ measurements included atmospheric thermodynamic and dynamic state parameters (air temperature, humidity, pressure, and three-dimensional wind), broadband solar and terrestrial irradiance, aerosol particle microphysical properties, and cloud particle images. The BELUGA observations aimed to characterize the cloudy Arctic atmospheric boundary layer above the sea ice using a modular setup of five instrument packages. ![]() During the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition, the Balloon-bornE moduLar Utility for profilinG the lower Atmosphere (BELUGA) was deployed from an ice floe drifting in the Fram Strait from 29 June to 27 July 2020. ![]()
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