Understanding the responses of air-sea carbon dioxide (CO₂) flux to rapid environmental changes in the highly productive Chukchi Sea is of great significance for the climate prediction in the Arctic Ocean. Through analyzing the 1998–2015 hindcast simulation of a coupled ocean–sea ice–biogeochemical model, this study identifies that the key factors influencing oceanic carbon uptake in the Chukchi Sea vary seasonally. The effects of these seasonal carbon uptakes on the total annual carbon sink vary at different timescales. The model solution suggests that the Chukchi Sea acts as a perennial carbon sink of atmospheric CO₂ with the annual mean influx of −3.73 ± 3.90 mmol m⁻² d⁻¹. Quantitative analyses reveal that the sea ice concentration predominates the annual cycle of air-sea CO₂ flux, while primary production and wind speed strengthen the capacity for carbon uptake during June–July (melt season) and October–December (freeze season), respectively. The total annual carbon sink shows an increasing trend during 1998–2015 with a multi-year average of 9.22 ± 1.93 Tg C y⁻¹. The carbon uptakes during June–July and August–September (open water season), which are respectively regulated by primary production and open water area at interannual scale, present significant long-term increases and jointly determine the secular increase trend of the total annual carbon sink. Interannual CO₂ absorption during the freeze season is sensitive to the sea ice concentration and wind conditions, presenting the greatest year-to-year variation but insignificant long-term trend, and modulates the interannual amplitude of the total annual carbon sink.

中文翻译：

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用耦合的海-海冰-生物地球化学模型分析楚科奇海海气CO2通量的季节和年际变化

了解海气二氧化碳（CO ₂）通量对高产楚科奇海快速环境变化的响应对于北冰洋的气候预测具有重要意义。本研究通过分析 1998-2015 年海洋-海冰-生物地球化学耦合模型的后报模拟，确定影响楚科奇海海洋碳吸收的关键因素随季节变化。这些季节性碳吸收对年度总碳汇的影响在不同的时间尺度上有所不同。模型解表明楚科奇海是大气 CO ₂的常年碳汇，年平均流入量为 -3.73 ± 3.90 mmol m ^-2  d ^-1. 定量分析表明，海冰浓度在海气CO ₂通量的年循环中占主导地位，而初级生产和风速分别增强了6-7月（融化季节）和10-12月（冻结季节）的碳吸收能力. 1998-2015年年碳汇总量呈增加趋势，多年平均值为9.22±1.93 Tg C y ^-1。6-7 月和 8-9 月（开放水域季节）的碳吸收量分别受初级生产和开放水域面积的年际尺度调节，呈现显着的长期增长趋势，共同决定了全年碳总量的长期增长趋势。下沉。年际 CO ₂ 冰冻季节的吸收对海冰浓度和风况敏感，呈现出最大的逐年变化，但长期趋势不显着，并调节年度总碳汇的年际幅度。