Influence of Atlantic inflow on the freshwater content in the upper layer of the Arctic basin

• Published in: Arctic and Antarctic Research
• Main Authors: G. V. Alekseev, A. V. Pnyushkov, A. V. Smirnov, A. E. Vyazilova, N. I. Glok, Г. В. Алексеев, А. В. Пнюшков, А. В. Смирнов, А. Е. Вязилова, Н. И. Глок
• Other Authors: The research is supported by the Russian Foundation for Basic Research, Project 18-05-60107, Исследование выполнено при поддержке Российского фонда фундаментальных исследований (проект 18-05-60107)
• Format: Article in Journal/Newspaper
• Language: Russian
• Published: Государственный научный центр Российской Федерации Арктический и антарктический научно-исследовательский институт 2019
• Subjects: содержание пресной воды; Atlantic inflows; freshwater content; polar changes; вода из Атлантики; полярные изменения; Antarctic; Arctic; Barents Sea; North Pole; Antarc*; Arctic and Antarctic Research Institute; Arctic Basin; Fram Strait; International Arctic Research Center; International Arctic Research Center (IARC)
• Online Access: https://www.aaresearch.science/jour/article/view/215; https://doi.org/10.30758/0555-2648-2019-65-4-363-388

Inter-decadal changes in the water layer of Atlantic origin and freshwater content (FWC) in the upper 100 m layer were traced jointly to assess the influence of inflows from the Atlantic on FWC changes based on oceanographic observations in the Arctic Basin for the 1960s – 2010s. For this assessment, we used oceanographic data collected at the Arctic and Antarctic Research Institute (AARI) and the International Arctic Research Center (IARC). The AARI data for the decades of 1960s – 1990s were obtained mainly at the North Pole drifting ice camps, in high-latitude aerial surveys in the 1970s, as well as in ship-based expeditions in the 1990s. The IARC database contains oceanographic measurements acquired using modern CTD (Conductivity – Temperature – Depth) systems starting from the 2000s. For the reconstruction of decadal fields of the depths of the upper and lower 0 °С isotherms and FWC in the 0–100 m layer in the periods with a relatively small number of observations (1970s – 1990s), we used a climatic regression method based on the conservativeness of the large-scale structure of water masses in the Arctic Basin. Decadal fields with higher data coverage were built using the DIVAnd algorithm. Both methods showed almost identical results when compared. The results demonstrated that the upper boundary of the Atlantic water (AW) layer, identified with the depth of zero isotherm, raised everywhere by several tens of meters in 1990s – 2010s, when compared to its position before the start of warming in the 1970s. The lower boundary of the AW layer, also determined by the depth of zero isotherm, became deeper. Such displacements of the layer boundaries indicate an increase in the volume of water in the Arctic Basin coming not only through the Fram Strait, but also through the Barents Sea. As a result, the balance of water masses was disturbed and its restoration had to occur due to the reduction of the volume of the upper most dynamic freshened layer. Accordingly, the content of fresh water in this layer should ...