ALEXIA - Analysis Linking Arctic Methane, Carbon Release, Heat Fluxes and Sea Ice from Local to Sub-Regional Scales by Airborne Measurements

人们对北冰洋及其海冰覆盖层和极地大气之间的热量、水蒸气、二氧化碳和甲烷交换仍然知之甚少，但对提高对北极气候变化的认识具有重要意义。从局地尺度到气候相关尺度，分析大气、海冰、海洋和生物地圈的空间变异和相互作用对提高气候模式的性能至关重要。为了填补当地地面现场测量与北冰洋中部大尺度遥感和数值数据之间的空白，在国际MOSAiC实验期间，将通过直升机测量获得机载数据集。从2019年9月起，“极地之星”号科考船将在北冰洋度过一年，与北极上空的海冰一起从北极的俄罗斯部分漂流到格陵兰岛。ALEXIA（通过航空测量将北极甲烷、碳释放、热通量和海冰从地方到次区域尺度联系起来的分析）提案的目标如下：研究从局地到漂流试验周围半径100公里范围内的气象和地面参数及其变率，研究海冰和天气条件对从地面到大气的热量和水分输送的影响，量化海洋通过冰进入大气的甲烷和二氧化碳的垂直输送，并区分这些温室气体的高纬度来源和远距离输送。并通过对空气样本的同位素分析，确定春秋两季甲烷浓度升高的原因。宝贵的数据池将用于不同的跨学科分析，以进一步了解高纬度相互作用，并在未来作为数值模拟的输入和工具，其总体目标是减少未来气候变化情景的不确定性。

The exchange of heat, water vapour, carbon dioxide and methane between Arctic Ocean, its sea ice cover and the polar atmosphere is still poorly known but of high importance for improved understanding of Arctic climate change. Analysis of the spatial variability and interactions of atmosphere, sea ice, ocean and biogeosphere from local to climatically relevant scales is critical to improve the performance of climate models. To fill the gap between local ground-based in situ measurements and large scale remote sensing and numerical data in the Central Arctic Ocean, an airborne data set will be obtained with helicopter based measurements during the international MOSAiC experiment, where the research vessel Polarstern will spend one year in the Arctic Ocean from September 2019 on, drifting with the sea ice above the North Pole from the Russian part of the Arctic towards Greenland. The proposal ALEXIA (Analysis Linking Arctic Methane, Carbon Release, Heat Fluxes and Sea Ice from Local to Sub-Regional Scales by Airborne Measurements) has the following aims: to investigate meteorological and surface parameters and their variability on a scale from local to a radius of 100 km around the drifting experiment, to study the impact of sea ice and synoptic conditions on heat and moisture transfer from the surface into the atmosphere, to quantify the vertical transport of methane and carbon dioxide from the ocean through the ice into the atmosphere and to distinguish the high-latitude source from long-range transport of these greenhouse gases, and to constrain the origin of the enhanced methane concentration in the shoulder seasons spring and autumn by isotopic analyses of air samples. The valuable data pool will be used for different interdisciplinary analyses for an advanced understanding of high-latitude interactions, and in the future as input and tool for numerical simulations with the overall aim to reduce uncertainty about future climate change scenarios.