Land-atmosphere exchange processes are determined by turbulent fluxes, which can be derived from eddy-covariance measurements. This method was established to quantify ecosystem-scale vertical atmosphere-vegetation exchange processes, but is also used to validate atmospheric turbulence theories with the ultimate aim to improve the representation of turbulence in numerical models. While the focus has long been on turbulence over idealized, homogeneous and flat surfaces, recent scientific developments are shifting towards investigating turbulent exchange processes in complex heterogeneous environments under non-idealized conditions, which pose particular challenges, e.g. advective fluxes between different surface types or non-stationarity of nighttime turbulence. This requires to rethink standard post-processing routines for determining turbulent fluxes from the high-frequency sonic and gas analyzer measurements. Here, we introduce the open-source R-package 'Reddy', which provides modular-built functions for post-processing, analysis and visualization of eddy-covariance measurements, including investigating spectra, coherent structures, anisotropy, flux footprints and surface energy balance closure. The 'Reddy' package is accompanied by a detailed documentation and a set of jupyter notebooks introducing new users hands-on to eddy-covariance data analysis. We showcase 'Reddy' based on measurements from three different sites in Norway: A case study during strong stratification over alpine tundra, for determining suitable averaging times during ice-cover transition at a boreal lake, and for fitting flux-variance relations for a permafrost peatland. 'Reddy' serves as extension of previously developed software packages, paving the way towards holistic turbulence data analysis in heterogeneous real-world environments.

翻译：陆地-大气交换过程由湍流通量决定，这些通量可通过涡动协方差测量推导得出。该方法最初用于量化生态系统尺度的垂直大气-植被交换过程，现亦用于验证大气湍流理论，其最终目标是改进数值模型中湍流的表征方式。长期以来，研究重点集中于理想化、均质平坦表面上的湍流，而近期科学进展正转向研究非理想条件下复杂异质环境中的湍流交换过程，这带来了特殊挑战，例如不同地表类型间的平流通量或夜间湍流的非平稳性。这要求重新思考从高频超声风速仪和气体分析仪测量数据中确定湍流通量的标准后处理流程。本文介绍开源R软件包“Reddy”，该软件包提供模块化构建的函数，用于涡动协方差测量的后处理、分析和可视化，包括研究频谱、相干结构、各向异性、通量足迹和地表能量平衡闭合度。“Reddy”软件包配有详细文档和一组Jupyter Notebook教程，可引导新用户实际操作涡动协方差数据分析。我们基于挪威三个不同站点的测量数据展示“Reddy”的功能：包括强分层条件下高山苔原的案例研究、北方湖泊冰盖过渡期适宜平均时长的确定，以及永久冻土泥炭地通量-方差关系的拟合。“Reddy”作为先前开发软件包的扩展工具，为在异质现实环境中开展整体性湍流数据分析铺平了道路。