Sea ice volume variability and water temperature in the Greenland Sea

• Main Authors: Selyuzhenok, Valeria, Bashmachnikov, Igor, Ricker, Robert, Vesman, Anna, Bobylev, Leonid
• Format: Text
• Language: English
• Published: 2019
• Subjects: Arctic; Greenland; Fram Strait; Greenland Sea; Nordic Seas; North Atlantic; North Atlantic oscillation; Sea ice
• Online Access: https://doi.org/10.5194/tc-2019-117; https://www.the-cryosphere-discuss.net/tc-2019-117/

This study explores a link between the long-term variations in the integral sea ice volume (SIV) in the Greenland Sea and oceanic processes. Using Pan-Arctic Ice Ocean Modelling and Assimilation System (PIOMAS, 1979–2016), we show that the negative tendencies in SIV go in parallel with the increasing ice flux through the Fram Strait. The overall SIV loss in the Greenland Sea comprises 113 km 3 per decade, while the total SIV import through the Fram strait is increasing by 115 km 3 per decade. An analysis of the ocean temperature and the mixed layer depth (MLD) in the marginal sea ice zone (MIZ), based on ARMOR data-set (1993–2016), revealed doubling of the amount of the upper ocean heat content available for the ice melt in the MIZ. This increase over the 24-year period can solely explain the SIV loss in the Greenland Sea, even when accounting for the increasing SIV flux from the Arctic. The increase in the ocean heat content is found to be linked to an increase in the temperature of the Atlantic water in the Nordic seas, following an increase of ocean heat flux form the subtropical North Atlantic. We argue that the predominantly positive North Atlantic Oscillation (NAO) index during the four recent decades, together with the intensification of the deep convection in the Greenland Sea, are responsible for the overall intensification of the circulation in the Nordic seas, which explains the observed long-term variations of the SIV.