School of Earth and Environmental Sciences, Seoul National University, Seoul, Republic of Korea.
Department of Environmental Planning, Graduate School of Environmental Studies, Seoul National University, Seoul, Republic of Korea.
Glob Chang Biol. 2020 Jun;26(6):3368-3383. doi: 10.1111/gcb.15061. Epub 2020 Apr 13.
Understanding changes in terrestrial carbon balance is important to improve our knowledge of the regional carbon cycle and climate change. However, evaluating regional changes in the terrestrial carbon balance is challenging due to the lack of surface flux measurements. This study reveals that the terrestrial carbon uptake over the Republic of Korea has been enhanced from 1999 to 2017 by analyzing long-term atmospheric CO concentration measurements at the Anmyeondo Station (36.53°N, 126.32°E) located in the western coast. The influence of terrestrial carbon flux on atmospheric CO concentrations (ΔCO ) is estimated from the difference of CO concentrations that were influenced by the land sector (through easterly winds) and the Yellow Sea sector (through westerly winds). We find a significant trend in ΔCO of -4.75 ppm per decade (p < .05) during the vegetation growing season (May through October), suggesting that the regional terrestrial carbon uptake has increased relative to the surrounding ocean areas. Combined analysis with satellite measured normalized difference vegetation index and gross primary production shows that the enhanced carbon uptake is associated with significant nationwide increases in vegetation and its production. Process-based terrestrial model and inverse model simulations estimate that regional terrestrial carbon uptake increases by up to 18.9 and 8.0 Tg C for the study period, accounting for 13.4% and 5.7% of the average annual domestic carbon emissions, respectively. Atmospheric chemical transport model simulations indicate that the enhanced terrestrial carbon sink is the primary reason for the observed ΔCO trend rather than anthropogenic emissions and atmospheric circulation changes. Our results highlight the fact that atmospheric CO measurements could open up the possibility of detecting regional changes in the terrestrial carbon cycle even where anthropogenic emissions are not negligible.
理解陆地碳平衡的变化对于提高我们对区域碳循环和气候变化的认识非常重要。然而，由于缺乏地表通量测量，评估陆地碳平衡的区域变化具有挑战性。本研究通过分析位于韩国西海岸的安岳岛站（36.53°N，126.32°E）的长期大气 CO 浓度测量数据，揭示了自 1999 年至 2017 年期间韩国陆地碳吸收的增强。通过比较受陆地（通过东风）和黄海（通过西风）影响的 CO 浓度差异，估算陆地碳通量对大气 CO 浓度（ΔCO）的影响。我们发现，在植被生长季节（5 月至 10 月），ΔCO 呈显著下降趋势，每十年下降 4.75ppm（p<.05），表明相对于周围海洋地区，区域陆地碳吸收增加。与卫星测量的归一化差异植被指数和总初级生产力的综合分析表明，增强的碳吸收与植被及其生产力的全国性显著增加有关。基于过程的陆地模型和反演模型模拟估计，在研究期间，区域陆地碳吸收增加了 18.9TgC 和 8.0TgC，分别占平均年国内碳排放的 13.4%和 5.7%。大气化学输送模型模拟表明，增强的陆地碳汇是观察到的ΔCO 趋势的主要原因，而不是人为排放和大气环流变化。我们的研究结果强调了一个事实，即大气 CO 测量可能为检测陆地碳循环的区域变化提供可能性，即使在人为排放不可忽略的情况下也是如此。
