Author(s): Qingkai Wang; Peng Lu; Zhijun Li; Bing Tan
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Abstract: As a part of Chinese National Arctic Research Expedition program, the physical properties of sea ice were investigated in the Pacific sector of the Arctic during the summers of 2008−2018. Sea ice salinity, density, and temperature were measured in field at 21 first-year ice (FYI) sites and 20 multi-year ice (MYI) sites. Results show that the bulk salinity ranged from 0.4 to 3.2 PSU for FYI and 0.4–2.4 PSU for MYI. The bulk density of FYI was 600−900 kg/m3, and of MYI was 686−903 kg/m3. Both the measured salinity and density were less than the previously reported values, and their earlier parameterization formulae were not appropriate for the current summer Arctic sea ice. Therefore, several modifications were proposed based on our measurements. Furthermore, the contents of brine and gas within sea ice were evaluated according to the volume fractions calculated using sea ice temperature, salinity, and density. The bulk brine volume fraction ranged from 3.0 to 25.9% for FYI and from 2.2 to 21.4% for MYI. The bulk gas volume fraction ranges were 2.7−35.4% and 3.6−26.1% for FYI and MYI, respectively. The typical variations of brine and gas volume fractions along ice depth were parameterized using quadratic polynomials. Large changes have been observed in the physical states of current Arctic sea ice compared with earlier observations, and the results can be helpful to improve the accuracy of existing sea ice models.
Year: 2020