Northern high latitudes are likely to be heavily impacted by climate change, changes that will undoubtedly alter carbon cycling across these regions. An understanding of both the magnitude and drivers of current CO₂ and CH₄ fluxes are a prerequisite for making robust projections of future changes. In this study, we use observations from the recent Airborne Carbon Measurements (ACME-V) aircraft campaign to estimate the magnitude and environmental predictors CO₂ and CH₄ fluxes in Alaska. ACME-V consisted of 38 flights across the North Slope between late May and mid-September 2015, making it the most detailed airborne survey of northern Alaska to date. These data, combined with a geostatistical inverse model, provide a unique lens into fluxes across the region. Using this approach, we estimate a large CO₂ flux to the atmosphere from the North Slope of Alaska in early summer that is counterbalanced by CO₂ uptake in late summer; this balance between early season respiration and late-summer photosynthesis drives the total summer CO₂ flux across northern Alaska during the study period. We further compare our results to process-based flux estimates (the Terrestrial Model Intercomparison Project, MsTMIP and the Wetland and Wetland CH₄ Inter-comparison of Models Project, WETCHIMP) and several recent studies of the same spatial domain. We observe a similarity in CO₂ flux totals between MsTMIP suite of models and our study (June 2015 -0.86 – 0.57 vs 0.96, July 2015 MsTMIP -1.01 – 0.00 vs -0.14 and August 2915 MsTMIP -0.73 – 0.29 vs -0.50 μmol m^-2 s^-1, MsTMIP and our study, respectively, averaged across the North Slope). However, we find significantly higher CH₄ fluxes from the North Slope than any of the WETCHIMP models. Specifically, we estimate total CH₄ fluxes from the North Slope of Alaska of +0.64 +/- 0.13 Tg (95% confidence), during June through August 2015 while the WETCHIMP model estimates range from 0.004 to 0.1 Tg, depending upon the model. Furthermore, the contribution of the North Slope tundra to the overall Alaskan CH₄ fluxes during the entire period was ∼27%, compared to 3% in state-of-the-art process-based models.

北部高纬度很可能会受到气候变化的严重影响，这些变化无疑会改变这些地区的碳循环。了解当前CO ₂和CH ₄通量的大小和驱动因素是对未来变化做出可靠预测的前提。在这项研究中，我们使用来自最近的机载碳测量（ACME-V）飞机运动的观测值来估算CO ₂和CH ₄的大小和环境预测因子通量在阿拉斯加。ACME-V在2015年5月下旬至9月中旬之间共进行了38次穿越北坡的飞行，这是迄今为止对阿拉斯加北部进行的最详细的机载测量。这些数据与地统计反演模型相结合，为进入整个区域的通量提供了独特的视角。使用这种方法，我们估计在夏季初从阿拉斯加北坡向大气中有大量的CO ₂通量，而在夏季末则吸收了CO ₂。夏季呼吸和夏季后期光合作用之间的这种平衡驱动了夏季的总CO ₂在研究期间穿越阿拉斯加北部的水流。我们进一步将结果与基于过程的通量估计值（陆地模型比对项目，MsTMIP和湿地和湿地CH ₄模型比对项目，WETCHIMP）以及同一空间领域的一些近期研究进行比较。我们观察到MsTMIP模型套件和我们的研究之间的CO ₂通量总量相似（2015年6月-0.86 – 0.57 vs 0.96，2015年7月MsTMIP -1.01 – 0.00 vs -0.14和2915年8月MsTMIP -0.73 – 0.29 vs -0.50μmolm ^-2 s ^-1，MsTMIP和我们的研究分别在北坡上平均）。但是，我们发现CH ₄明显更高北坡的通量比任何WETCHIMP模型都高。具体而言，我们估计总CH _4个通过2015年8月通量从阿拉斯加北坡0.64 +/- 0.13的Tg（95％置信度），六月期间而WETCHIMP模型估计值的范围从0.004至0.1的Tg，这取决于模型。此外，在整个过程中，北坡冻土带对整个阿拉斯加CH ₄通量的贡献约为27％，而在最新的基于过程的模型中为3％。