Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

UP: Fachverband Umweltphysik

UP 3: Kryosphäre

UP 3.2: Vortrag

Dienstag, 14. März 2017, 11:30–11:45, GW2 B3009

Sea ice in the Arctic and Antarctic: recent developments and understanding — •Gunnar Spreen¹, Malte Gerken¹, Christian Haas², Stefan Hendricks², Christian Melsheimer¹, Marcel Nicolaus², Renate Treffeisen¹, Justus Notholt¹, and Georg Heygster¹ — ¹University of Bremen — ²Alfred Wegener Institute

Air temperatures in the Arctic are increasing twice as fast as the global mean. As a consequence, the sea ice extent in the Arctic is declining (4%/decade). In summer the decline is strongest. In conjunction also ice thickness, volume, and age decrease while ice drift speed and melt season length increase. 2016 was an extreme year: due to mild temperatures, the winter sea ice maximum in March was the lowest on record. The modal ice thickness was about 35% below average. Due to cooler Arctic summer temperatures, the 2016 sea ice minimum was only second lowest. In autumn above average air temperatures prevailed, causing a late Arctic sea ice freeze up. The average sea ice extent in November 2016 was the lowest November value observed. The average 2016 sea ice extent therefore likely will be the lowest on record. In the Antarctic, sea ice extent is increasing by 1.5%/decade due to more divergent ice dynamics in recent years. In early Antarctic summer 2016, however, the ice extent is much below climatology. While not connected, the low ice extent in Arctic and Antarctic result in a record low worldwide sea ice area. We will present the latest data and discuss causes of the unusual 2016 sea ice situation. Observations from multiple satellite sensors allow a comprehensive analysis by not only taking ice area but also ice thickness and drift into account.