Identification of Air Masses Responsible for Warm Events on the East Antarctic Coast

• Published in: SOLA
• Main Authors: Kurita, Naoyuki, Hirasawa, Naohiko, Koga, Seizi, Matsushita, Junji, Steen-Larsen, Hans Christian, Masson-Delmotte, Valerie, Fujiyoshi, Yasushi
• Format: Article in Journal/Newspaper
• Language: English
• Published: 公益社団法人 日本気象学会
• Subjects: Antarctic; Austral; Syowa Station; The Antarctic; Antarc*; Enderby Land
• Online Access: http://hdl.handle.net/2115/64668; https://doi.org/10.2151/sola.2016-060

Warm events, periods when rising surface air temperatures can trigger surface melt, have been recorded during the austral summer at Syowa station on the East Antarctic coast. This study identifies air masses responsible for summer warm events at Syowa. Air masses arriving at Syowa are classified into marine and glacial sources based on their isotopic characteristics. Warm events are not associated with moist marine air intrusion, but with the downward flow of dry glacial air along the west side slope of the mountains in Enderby Land (EL). We use simulations from the Antarctic Mesoscale Prediction System (AMPS) to explore the atmospheric process responsible for the warmest event at Syowa. The model output illustrates several foehn-associated features such as low-level blocking, precipitation on the mountain's windward side, and mountain wave activity, with warm air ascending on the upstream slope and descending to Syowa. The foehn warming is caused by an easterly cross-mountain flow associated with a low-pressure system to the north of the EL coast. Future changes in synoptic cyclonic activity off the EL coast may have a significant impact on the frequency and intensity of foehn events at Syowa and the associated coastal warm events.