Collaborative Research: Bridging the scale gap between local and regional methane and carbon dioxide isotopic fluxes in the Arctic

合作研究：缩小北极当地和区域甲烷和二氧化碳同位素通量之间的规模差距

• 批准号: 2427291
• 负责人: James Anderson
• 金额: $ 80.56万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-03-15 至 2024-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2427291&HistoricalAwards=false
• 关键词: Collaborative; Research; Bridging; scale; gap

Northern latitudes are warming at twice the global mean, making carbon stored in permafrost increasingly vulnerable to thaw and decomposition by microbes, potentially leading to large increases in methane (CH4) and carbon dioxide (CO2) emissions, both important greenhouse gases. Accurate and reliable forecasts of greenhouse gas emissions are critical for the improvement of global models that predict changes to temperature and to sea level. On a local level, the data and modeling products can be used to better inform local populations of the changes happening to their environment and help predict likely changes in the future. Improvements to regional and global scale models require advancement in the current knowledge of methane and carbon dioxide flux sources to gain insight into how the net flux is expected to respond to a warming Arctic. Comparing aircraft derived fluxes to local tower measurements and land classification maps allows for the determination of which mechanisms are primarily responsible for the variation in emissions. Data, models, and analysis directly measuring the fluxes over regional scales close to the surface and measuring fluxes using inverse modeling helps to better understand the differences. Data generated from this project are important for evaluating which combination of environmental quantities and categorical quantities are best suited for predicting methane and carbon dioxide emissions to produce more accurate estimates from remotely sensed variables and will also be compared with existing carbon emissions models. The ability to define the current late summer and autumn net flux of methane and carbon dioxide from the North Slope and adjoining Arctic waters is required to establish a benchmark for quantitatively tracking the annual time series of net carbon flux from the Arctic.This research provides emission measurements of CO2 and CH4 plus nitrous oxide (N2O), and water vapor (H2O) from the North Slope of Alaska on a small aircraft operating at altitudes from 10 m to 10 km, with custom-built spectroscopic sensors, an air turbulence probe, and GPS systems. This project bridges the scale gap between local studies of carbon emissions in the Arctic, such as those from flux towers, and large regional scale emissions estimates from inversion modeling. The work provides resolved emissions correlated with underlying sources; regional coverage for comprehensive analysis of carbon emissions in this part of the Arctic basin; direct coupling of the observations with other observing systems ranging from small tower measurements to satellite remote sensing; and coupling of the observations to an air transport model to compare direct emission measurements to top-down estimates of regional emissions based on profile measurements in the atmosphere. Specifically, aircraft eddy covariance measurements and vertical profiles are used to effectively scale process measurements from short eddy covariance towers to the regional scale, allowing for determining how representative certain areas are of the larger North Slope with respect to flux of the major gases that contribute to changes in radiative forcing. Observations and modeling of fluxes and concentrations of molecules that differ in their isotopic composition reveal the contributions of key source processes at local, landscape, and regional scale, a feature unique to this project. This project creates an analysis framework to allow for the combination of in situ concentrations and fluxes with regional fluxes calculated using a transport model that both is adapted for Alaska and widely applicable to other circumpolar areas.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

北部纬度的变暖是全球平均值的两倍，使碳储存在越多的冻土中，越来越容易被微生物解冻和分解，可能导致甲烷（CH4）和二氧化碳（CO2）排放的大量增加，这两种氧化物都有重要的温室气体。对温室气体排放的准确和可靠的预测对于改善预测温度和海平面变化的全球模型至关重要。在本地一级，数据和建模产品可用于更好地告知本地人群其环境发生的变化，并帮助预测未来的可能变化。对区域和全球规模模型的改进需要在当前对甲烷和二氧化碳通量来源的了解方面提高，以洞悉预期净通量如何对北极变暖的反应。将飞机衍生的通量与当地塔测量值和土地分类图进行比较，可以确定哪些机制主要负责排放变化。数据，模型和分析直接测量靠近表面的区域尺度上的通量，并使用反向建模测量通量有助于更好地理解差异。该项目产生的数据对于评估哪种环境数量和分类数量的组合最适合预测甲烷和二氧化碳排放，以产生更准确的估计，从远程感知的变量中进行了更准确的估计，并且还将与现有的碳排放模型进行比较。需要定义当前夏末和秋末甲烷和二氧化碳从北坡以及北极水域的甲烷和二氧化碳的净通量，需要建立一个基准，以定量跟踪北极的净碳通量的年度时间序列。这项研究提供了CO2和CH4和CH4 Plus of Slose（n2o）（n2o）（n2o）的净碳通量（HES），以及n2o的SLES sl vapo（n2o）（n2o）（n2o）。小型飞机在10 m至10 km的高度运行，并带有定制的光谱传感器，空气湍流探针和GPS系统。该项目弥合了北极碳排放的本地研究（例如磁通塔的碳排放量）与反转建模的大型区域尺度排放估算之间的规模差距。这项工作提供了与潜在来源相关的解决排放；区域覆盖范围，以全面分析北极盆地这一部分的碳排放；直接耦合观察结果与其他观测系统的耦合，从小塔测量到卫星遥感；并将观测值与航空传输模型的耦合，以将直接排放测量结果与基于大气中剖面测量值的区域排放估计值进行比较。具体而言，飞机涡流协方差测量和垂直轮廓用于从短涡流协方差塔到区域尺度的有效扩展过程测量，从而确定对某些较大的北坡的代表性相对于较大的北坡度的主要气体，这对辐射强迫变化的影响。其同位素组成不同的磁通量和分子浓度的观测和建模揭示了该项目在本地，景观和区域尺度上关键源过程的贡献，这是该项目独有的特征。该项目创建了一个分析框架，以允许将原位浓度和通量与使用运输模型计算得出的区域通量结合使用，该模型都适用于阿拉斯加，并且广泛适用于其他近极区域。该奖项反映了NSF的法定任务，并被认为是通过基金会的知识优点和广泛的criperia criperia criperia criperia criperia criperia criperia criperia criperia criperia criperia criperia criperia criperia criperia criperia rection the Apportiation。