Horizontal km Scale Variability of Arctic Sea Ice and Atmospheric Dynamics, Aerosol, Trace Gases and Radiation for Investigating Interaction Processes of the Earth System Compartments during the Melting Season (HELiPOD4ArtofMelt)

HELiPOD4ArtofMelt项目的总体目标是帮助了解暖空气入侵对北极大气的影响，并了解决定北极海冰融化空间不均匀开始的过程和反馈机制。该方法包括分析2023年5月/ 6月瑞典破冰船奥登号在北冰洋大西洋地区进行的“融化艺术”考察期间获得的机载现场数据。直升机机载探空仪HELiPOD部署了大量传感器，用于表征海冰表面的空间分布和特性、大气动力学、气溶胶、微量气体和奥登周围100公里范围内的辐射预算。奥登考察队的其他国际参与者的补充传感器包括在HELiPOD中，例如用于调查水蒸气同位素以研究蒸发，用于测定冰核颗粒以将观测结果与云特性联系起来，用于测量一氧化碳浓度，烟尘浓度，以及用于随后微观实验室分析的过滤器采样器。在低海拔15-20 m范围内进行了长飞行腿，研究了海洋-海洋冰-空气交换过程，并进行了垂直剖面研究大气稳定性和参数的垂直分布和变率。不同参数的同步数据集可以量化关系和相互作用，例如，融化池分数增加的面积可以直接与感热通量和潜热通量的变化、气溶胶粒径分布和数量浓度的变化以及随后在小空间尺度上表面能量平衡的变化有关。除了对奥登的连续测量外，HELiPOD数据还提供了空间变异性的信息。在对大数据集进行最后的后处理后，确定不同参数的空间变异性，得到1 km以下至100 km尺度上的三维图像。与国际合作伙伴一起进行的分析的一个特别重点是描述所谓的“大气河流”的特征，即在北极穹顶平流暖湿气团的环流模式，以量化大气边界层的特性和变化，例如垂直温度剖面和热通量的变化，这些变化最终影响融化。此外，基于航空观测、奥登号连续观测以及斯瓦尔巴群岛、格陵兰岛和斯堪的纳维亚半岛北部的泛北极观测站网络，研究了导致时空不均匀海冰融化开始的过程和相互作用。

The project HELiPOD4ArtofMelt has the overall aims to contribute to understanding the impact of warm-air intrusions on the Arctic atmosphere, and to understanding processes and feedback mechanisms determining the spatially inhomogeneous onset of Arctic sea ice melt. The method consists in the analysis of airborne field data obtained during the expedition Art of Melt of the Swedish ice breaker Oden in the Atlantic sector of the Arctic Ocean in May/June 2023. The helicopter borne sonde HELiPOD is deployed with a multitude of sensors for characterising the spatial distribution and properties of the sea ice surface, atmospheric dynamics, aerosol, trace gases and radiation budget within a range of up to 100 km around the Oden. Additional complementary sensors of the international participants of the Oden expedition are included in the HELiPOD, e.g. for investigating the water vapour isotopes to study evaporation, for determining ice nucleation particles to relate the observations to cloud properties, for measuring the carbon monoxide concentration, the soot concentration, and filter samplers for subsequent microscopic laboratory analyses. Long flight legs are performed at low altitudes in the range of 15-20 m to study the ocean-sea ice-air exchange processes, and vertical profiles are done to investigate atmospheric stability and the vertical distribution and variability of the parameters. The simultaneous data sets of the different parameters allow quantifying relations and interactions, e.g. an area of increased melt pond fraction can be related directly to changes in sensible and latent heat fluxes, modifications in aerosol particle size distribution and number concentration, and subsequent alteration of the surface energy balance on small spatial scales. In addition to the continuous measurements on the Oden, the HELiPOD data provide information on the spatial variability. After final postprocessing of the large data set, the spatial variability of the different parameters is determined to derive a three-dimensional picture on the scale from below 1 km to 100 km. A special focus of the analyses with the international partners is on the characterisation of so-called „atmospheric rivers“, circulation patterns that advect warm and moist air masses in the Arctic dome, to quantify properties and modification of the atmospheric boundary layer, e.g. changes in the vertical temperatue profiles and heat fluxes, which finally impact melting. Further, the processes and interactions contributing to the spatially and temporally inhomogeneous sea ice melting onset are investigated based on the airborne observations, continuous measurements aboard Oden, and taking into account the pan-Arctic measurement network of observatories in Svalbard, Greenland and northern Scandinavia.