Kim Kwang-Yul, Kim Ji-Young, Kim Jinju, Yeo Saerim, Na Hanna, Hamlington Benjamin D, Leben Robert R
School of Earth and Environmental Sciences, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea.
APEC Climate Center 1463, Haeundae-gu, Busan, 48058, Republic of Korea.
Sci Rep. 2019 Feb 4;9(1):1184. doi: 10.1038/s41598-018-38109-x.
Sea ice reduction is accelerating in the Barents and Kara Seas. Several mechanisms are proposed to explain the accelerated loss of Arctic sea ice, which remains to be controversial. In the present study, detailed physical mechanism of sea ice reduction in winter (December-February) is identified from the daily ERA interim reanalysis data. Downward longwave radiation is an essential element for sea ice reduction, but can primarily be sustained by excessive upward heat flux from the sea surface exposed to air in the region of sea ice loss. The increased turbulent heat flux is used to increase air temperature and specific humidity in the lower troposphere, which in turn increases downward longwave radiation. This feedback process is clearly observed in the Barents and Kara Seas in the reanalysis data. A quantitative assessment reveals that this feedback process is being amplified at the rate of ~8.9% every year during 1979-2016. Availability of excessive heat flux is necessary for the maintenance of this feedback process; a similar mechanism of sea ice loss is expected to take place over the sea-ice covered polar region, when sea ice is not fully recovered in winter.
巴伦支海和喀拉海的海冰减少正在加速。人们提出了几种机制来解释北极海冰加速消融的现象，这一问题仍存在争议。在本研究中，利用每日ERA interim再分析数据确定了冬季（12月至2月）海冰减少的详细物理机制。向下的长波辐射是海冰减少的一个重要因素，但主要可由海冰流失区域中暴露于空气中的海面向上的过多热通量维持。增加的湍流感热通量用于提高对流层低层的气温和比湿，进而增加向下的长波辐射。在再分析数据中，巴伦支海和喀拉海清晰地观测到了这一反馈过程。定量评估表明，在1979 - 2016年期间，这一反馈过程正以每年约8.9%的速率增强。维持这一反馈过程需要有过多的热通量；当冬季海冰未完全恢复时，预计在海冰覆盖的极地地区会发生类似的海冰流失机制。
