Abstract. Ground-based instruments offer unique capabilities such as detailed atmospheric thermodynamic, cloud, and aerosol profiling at a high temporal sampling rate. The U.S. Department of Energy Atmospheric Radiation Measurement (ARM) user facility provides comprehensive datasets from key locations around the globe, facilitating long-term characterization and process-level understanding of clouds, aerosol, and aerosol-cloud interactions. However, as with other ground-based datasets, the fixed (Eulerian) nature of these measurements often introduces a knowledge gap in relating those observations with airmass hysteresis. Here, we describe ARMTRAJ, a set of multi-purpose trajectory datasets that helps close this gap in ARM deployments. Each dataset targets a different aspect of atmospheric research, including the analysis of surface, planetary boundary layer, distinct liquid-bearing cloud layers, and (primary) cloud decks. Trajectories are calculated using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model informed by the European Centre for Medium-Range Weather Forecasts ERA5 reanalysis dataset at its highest spatial resolution (0.25 degrees) and are initialized using ARM datasets. The trajectory datasets include information about airmass coordinates and state variables extracted from ERA5 before and after the ARM site overpass. Ensemble runs generated for each model initialization enhance trajectory consistency, while ensemble variability serves as a valuable uncertainty metric for those reported airmass coordinates and state variables. Following the description of dataset processing and structure, we demonstrate applications of ARMTRAJ to a case study and a few bulk analyses of observations collected during ARM’s Eastern Pacific Cloud Aerosol Precipitation Experiment (EPCAPE) field deployment. ARMTRAJ is expected to become a near real-time product accompanying new ARM deployments and an augmenting product to ongoing and previous deployments, promoting reaching science goals of research relying on ARM observations.

中文翻译：

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ARMTRAJ：一组增强大气辐射测量 (ARM) 用户设施测量的多用途轨迹数据集


摘要。地面仪器提供独特的功能，例如以高时间采样率进行详细的大气热力学、云和气溶胶剖面分析。美国能源部大气辐射测量 (ARM) 用户设施提供来自全球关键地点的综合数据集，促进对云、气溶胶以及气溶胶-云相互作用的长期表征和过程级理解。然而，与其他地面数据集一样，这些测量的固定（欧拉）性质通常会在将这些观测结果与气团滞后联系起来时引入知识差距。在这里，我们描述了 ARMTRAJ，这是一组多用途轨迹数据集，有助于缩小 ARM 部署中的这一差距。每个数据集针对大气研究的不同方面，包括表面、行星边界层、不同的含液体云层和（主）云层的分析。轨迹是使用欧洲中期天气预报中心 ERA5 再分析数据集提供的混合单粒子拉格朗日积分轨迹 (HYSPLIT) 模型以其最高空间分辨率（0.25 度）计算的，并使用 ARM 数据集进行初始化。轨迹数据集包括从 ARM 站点立交桥前后从 ERA5 中提取的气团坐标和状态变量的信息。为每个模型初始化生成的集合运行增强了轨迹一致性，而集合变异性对于那些报告的气团坐标和状态变量来说是一个有价值的不确定性度量。 在描述数据集处理和结构之后，我们演示了 ARMTRAJ 在案例研究中的应用，以及对 ARM 东太平洋云气溶胶降水实验 (EPCAPE) 现场部署期间收集的观测数据的一些批量分析。 ARMTRAJ 预计将成为伴随新 ARM 部署的近实时产品，以及当前和之前部署的增强产品，促进实现依赖 ARM 观测的研究科学目标。