Ocean College, Zhejiang University, Zhoushan, 316021, China.
Ocean College, Zhejiang University, Zhoushan, 316021, China.
Mar Environ Res. 2024 Nov;202:106770. doi: 10.1016/j.marenvres.2024.106770. Epub 2024 Sep 24.
The Northeast Pacific Ocean (NEP) is one of the important carbon sinks in the global ocean. The causes of carbon flux changes in this region have been widely studied, but the physical processes associated with large scale climate variability remain controversial primarily due to scarcity of spatially and temporally continuous observations. In this study, we constructed a high-resolution sea surface partial pressure of CO (pCO) from satellite observations for the NEP from 2003 to 2020 using the machine learning based XGBoost model. By analyzing the interannual large-scale high-latitude atmospheric dynamics and ocean physical conditions over the NEP, we find that the CO flux density (FCO) anomalies have a strong correlation with the Alaskan atmospheric blocking events. In the region north of 48°N, anomalous cyclones triggered by atmospheric blocking increased sea surface height (SSH), which reduced the replenishment of dissolved inorganic carbon (DIC) from deep seawater, leading to enhanced carbon uptake. By contrast, in the region south of 48°N, the increase in sea surface temperature (SST) triggered by atmospheric blocking reduced the solubility of CO in seawater, resulting in a decrease in regional carbon flux. These results provide new perspectives for better understanding and predicting the effects of high-latitude atmospheric dynamics on regional ocean carbon fluxes.
东北太平洋（NEP）是全球海洋中重要的碳汇之一。该地区碳通量变化的原因已被广泛研究，但由于缺乏时空连续的观测，与大尺度气候变率相关的物理过程仍存在争议。在这项研究中，我们使用基于机器学习的 XGBoost 模型，为 2003 年至 2020 年期间的 NEP 构建了高分辨率的海表二氧化碳分压（pCO）卫星观测结果。通过分析 NEP 上空多年际的大尺度高纬大气动力学和海洋物理条件，我们发现 CO 通量密度（FCO）异常与阿拉斯加大气阻塞事件密切相关。在北纬 48°以北的地区，大气阻塞引发的异常气旋会增加海面高度（SSH），减少来自深海的溶解无机碳（DIC）的补充，从而导致碳吸收增强。相比之下，在北纬 48°以南的地区，大气阻塞引发的海表温度（SST）升高会降低海水中 CO 的溶解度，导致区域碳通量减少。这些结果为更好地理解和预测高纬大气动力学对区域海洋碳通量的影响提供了新的视角。
