Observations and simulation of boundary layer clouds and fog over Dome C, Antarctica during the YOPP
Abstract
Recent studies of the atmospheric boundary layer at Dome C, Antarctica indicate the frequent presence of supercooled liquid water clouds at the top of the atmospheric boundary layer throughout the summer season. The occurrence of these liquid water clouds over the Eastern Anarctic Plateau is evident in remotely-sensed LIDAR and microwave radiometer data, and present in available CALIOPE passes; the impact of these clouds on both optical depth and radiative fluxes is pronounced in video and BSRN radiometric data. Additional radiosonde launches made possible as part of the Year of Polar Prediction allow for more detailed study of the dynamics of the formation, persistence and eventual dissipation of these clouds. Roughly 66% of the days with supercooled liquid water clouds also show the occurrence of thin layers of fog that appear suddenly and can easily obscure visibility. We explore several case studies from December 2018 and January 2019, selected for data availability and variety of synoptic settings. Simulations of these select cases are performed with two numerical weather prediction models, ARPEGE-SH, MAR and PolarWRF using state-of-the-art parameterizations of boundary layer processes. In general, the models perform well in simulating the evolution of the atmospheric boundary layer, and the occurrence of cloud. However, the simulated partitioning of cloud particles into ice and water, and the vertical distribution of this cloud is not representative of the remotely-sensed observations. As a result of these errors in simulated cloud phase and vertical extent, there are biases in the simulated radiative fluxes relative to those observed by the BSRN radiometers. We characterize the model performance relative to various synoptic situations with particular focus on an anomalous warming event from December 20-24, 2018 caused by penetration of a warm, moist marine air mass into the interior of the Eastern Antarctic.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMGC12A..08V
- Keywords:
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- 3305 Climate change and variability;
- ATMOSPHERIC PROCESSES;
- 3339 Ocean/atmosphere interactions;
- ATMOSPHERIC PROCESSES;
- 0750 Sea ice;
- CRYOSPHERE;
- 0764 Energy balance;
- CRYOSPHERE