Impacts of strong wind events on sea ice and water mass properties in Antarctic coastal polynyas

• Published in: Climate Dynamics
• Main Authors: Wang, Xiaoqiao, Zhang, Zhaoru, Wang, Xuezhu, Vihma, Timo, Zhou, Meng, Yu, Lejiang, Uotila, Petteri, Sein, Dmitry V.
• Other Authors: National Natural Science Foundation of China, shanghai science and technology committee, Shanghai Science and Technology Committee, National Key Research and Development Program of China, shanghai jiao tong university, European Commission Horizon 2020 Framework Program PolarRES, Academy of Finland, European Commission Horizon 2020 project PRIMAVERA, Federal Agency of Science Organizations, Russia
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science and Business Media LLC 2021
• Subjects: Atmospheric Science; Antarctic; Austral; East Antarctica; Prydz Bay; Shackleton; The Antarctic; Antarc*; Antarctica; Sea ice
• Online Access: http://dx.doi.org/10.1007/s00382-021-05878-7; https://link.springer.com/content/pdf/10.1007/s00382-021-05878-7.pdf; https://link.springer.com/article/10.1007/s00382-021-05878-7/fulltext.html

Abstract Strong offshore wind events (SOWEs) occur frequently near the Antarctic coast during austral winter. These wind events are typically associated with passage of synoptic- or meso-scale cyclones, which interact with the katabatic wind field and affect sea ice and oceanic processes in coastal polynyas. Based on numerical simulations from the coupled Finite Element Sea-ice Ocean Model (FESOM) driven by the CORE-II forcing, two coastal polynyas along the East Antarctica coast––the Prydz Bay Polynya and the Shackleton Polynya are selected to examine the response of sea ice and oceanic properties to SOWEs. In these polynyas, the southern or western flanks of cyclones play a crucial role in increasing the offshore winds depending on the local topography. Case studies for both polynyas show that during SOWEs, when the wind speed is 2–3 times higher than normal values, the offshore component of sea ice velocity can increase by 3–4 times. Sea ice concentration can decrease by 20–40%, and sea ice production can increase up to two to four folds. SOWEs increase surface salinity variability and mixed layer depth, and such effects may persist for 5–10 days. Formation of high salinity shelf water (HSSW) is detected in the coastal regions from surface to 800 m after 10–15 days of the SOWEs, while the HSSW features in deep layers exhibit weak response on the synoptic time scale. HSSW formation averaged over winter is notably greater in years with longer duration of SOWEs.