Merged Datasets for the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) Central Observatory in the Arctic Ocean (2019-2020) version 2

Major changes to the dataset with version 2 (see below for full description of dataset): - Data files have been separated into 'drift1' (October 2019-July 2020) and 'drift2' (August-September 2020) to highlight the spatial discontinuity in measurement sites. - Precipitation data is now provided for June 18 - July 31 of drift 1 and drift 2. - The code recipes for producing merged datasets were found to be infeasible to run on systems with limited random access memory (RAM). The code (https://doi.org/10.5281/zenodo.14633302) has been reorganized and a minutely-averaged version of the Atmospheric Radiation Measurement (ARM) ship-based radiation data is provided for convenience. - Ship-based radiation data has been updated to level b1 and now includes downwelling longwave data. Please see the methods (addendum 1) for a summary of the differences in downwelling radiation: Full description of the dataset: - The Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) produced a wealth of observational data along the drift of the R/V Polarstern in the Arctic Ocean from October 2019 to September 2020. These data can further process-level understanding and improvements in models. However, the observational records contain temporal gaps and are provided in different formats. One goal of the MOSAiC Model Forcing Dataset Working Group (MMFDWG: https://mosaic-expedition.org/science/cross-cutting_groups/) is to provide consistently-formatted, gap-filled, merged datasets representing the conditions at the MOSAiC Central Observatory (the intensively studied region within a few km of R/V Polarstern) that are suitable for driving models on this spatial domain (e.g., single column models, large eddy simulations, etc). The MSCMWG is an open group, please contact the dataset creators if you would like to contribute to future versions of these merged datasets (including new variables). - This dataset contains version 2 of these merged datasets, and comprises the variables necessary to force a single column ice model (e.g., Icepack: https://zenodo.org/doi/10.5281/zenodo.1213462). The atmospheric variables are primarily derived from Met City (https://doi.org/10.18739/A2PV6B83F), with temporal gaps filled by bias and advection corrected data from Atmospheric Surface Flux Stations ( https://doi.org/10.18739/A2XD0R00S, https://doi.org/10.18739/A25X25F0P, https://doi.org/10.18739/A2FF3M18K). Some residual gaps in shortwave radiation were filled with ARM ship-board radiometer data. See addendum 2 in the methods for a summary of the data sources for atmospheric data. - The MOSAiC expedition drifted with two distinct sets of drifting ice floes. 'drift1' began in October 2019 north of the Laptev Sea and ended in July 2020 in the Fram Strait. 'drift2' was from August to September 2020 in the vicinity of the North Pole. Distinct files are provided for drift1 and drift2. - Three different options for snowfall precipitation rate (prsn) for drift 1 are provided, based on in-situ observations that precipitation greatly exceeded accumulation on level ice, and accumulation rates varied on different ice types. See methods for a description of the different precipitation rates. Besides precipitation, the other atmospheric variables for these files are identical. - Oceanic variables are in MOSAiC_ocn* files and are derived from https://doi.org/10.18739/A21J9790B. Data format: The data are netCDF files formatted according to the Merged Data File format (https://doi.org/10.5194/egusphere-2023-2413, https://gitlab.com/mdf-makers/mdf-toolkit). Code availability: The code 'recipes' that were used to produce these data are available at: https://doi.org/10.5281/zenodo.14633302. References: If you use these datasets, please also cite the appropriate publications: - Meteorological variables (excluding precipitation): Cox et al., 2023 (https://doi.org/10.1038/s41597-023-02415-5) - Oceanographic variables: Schulz et al., 2024 (https://doi.org/10.1525/elementa.2023.00114) - Ka-band ARM Zenith Radar (KAZR)-derived precipitation: Matrosov et al., 2022 (https://doi.org/10.1525/elementa.2021.00101) - Accumulation-derived pseudo-precipitation: Raphael et al., 2024 (https://doi.org/10.1525/elementa.2023.00040). - Summertime precipitation: Smith et al., 2024 (https://doi.org/10.5194/egusphere-2024-1977) Known issues: The following are known issues that will be addressed in future dataset releases: 1. Residual gaps occupy approximately 7% of the data record (see addendum) 2. Measurement Data Format (MDF) format does not currently include a field for point-by-point data source 3. There is no precipitation data for the leg 3-4 crew transition (May 15 - June 19).本数据集2.0版本存在多项重大变更，完整数据集描述详见下文： - 数据文件已拆分为“drift1”（2019年10月—2020年7月）与“drift2”（2020年8月—9月）两个子集，以凸显观测站点的空间不连续性。 - 现已为drift1与drift2子集提供2019年6月18日—7月31日的降水数据。 - 原合并数据集的生成代码经测试发现，在随机存取内存（Random Access Memory, RAM）有限的系统中无法正常运行。现已对该代码（https://doi.org/10.5281/zenodo.14633302）进行重构，并额外提供了大气辐射测量（Atmospheric Radiation Measurement, ARM）船基辐射数据的分钟平均版本，以方便用户使用。 - 船基辐射数据已更新至b1级标准，新增下行长波辐射数据。有关下行辐射的差异详情，请参见方法部分的附录1： 完整数据集描述： - 北极气候研究多学科漂流观测站（Multidisciplinary drifting Observatory for the Study of Arctic Climate, MOSAiC）于2019年10月至2020年9月期间，在北冰洋沿“极星号”（R/V Polarstern）科考船的漂流轨迹收集了大量观测数据，这些数据有助于提升对过程级地表过程的认知与模式改进。但现有观测记录存在时间间隙，且数据格式不统一。北极气候研究多学科漂流观测站模型强迫数据集工作组（MOSAiC Model Forcing Dataset Working Group, MMFDWG，https://mosaic-expedition.org/science/cross-cutting_groups/）的核心目标之一，是提供格式统一、已填补间隙的合并数据集，以表征MOSAiC中央观测区（即“极星号”周边数公里内的重点研究区域）的环境条件，适用于该空间域内的模式驱动（如单柱模式、大涡模拟等）。本工作组为开放社群，若有意为后续版本的合并数据集（含新增变量）贡献力量，请联系数据集制作者。 - 本数据集包含上述合并数据集的2.0版本，涵盖驱动单柱海冰模式（如Icepack：https://zenodo.org/doi/10.5281/zenodo.1213462）所需的全部变量。大气变量主要来源于Met City数据集（https://doi.org/10.18739/A2PV6B83F），其时间间隙通过大气地表通量站经偏差校正与平流校正后的数据填补，相关数据来源包括：https://doi.org/10.18739/A2XD0R00S、https://doi.org/10.18739/A25X25F0P、https://doi.org/10.18739/A2FF3M18K。部分短波辐射的剩余间隙通过ARM船载辐射计数据填补。有关大气数据的数据源详情，请参见方法部分的附录2。 - MOSAiC科考航次随两块不同的漂流浮冰群完成漂流。“drift1”航段始于2019年10月的拉普捷夫海以北区域，于2020年7月在弗拉姆海峡结束；“drift2”航段为2020年8月至9月，位于北极点附近区域。现已为drift1与drift2分别提供独立数据文件。 - 针对drift1航段，本数据集提供了三种不同的降雪率（prsn）方案，其依据为原位观测结果：海冰水平面上的降水量远大于累积量，且不同冰型的累积速率存在差异。有关不同降雪率方案的详情，请参见方法部分。除降水数据外，上述文件中的其余大气变量完全一致。 - 海洋变量存储于MOSAiC_ocn*系列文件中，其数据来源于https://doi.org/10.18739/A21J9790B。 数据格式： 本数据集采用netCDF（网络通用数据格式，Network Common Data Form）文件，遵循合并数据文件格式规范（https://doi.org/10.5194/egusphere-2023-2413，https://gitlab.com/mdf-makers/mdf-toolkit）。 代码可用性： 用于生成本数据集的代码脚本现已公开，获取地址为：https://doi.org/10.5281/zenodo.14633302。 参考文献： 若使用本数据集，请同时引用以下相关文献： - 气象变量（降水除外）：Cox等人，2023（https://doi.org/10.1038/s41597-023-02415-5） - 海洋学变量：Schulz等人，2024（https://doi.org/10.1525/elementa.2023.00114） - Ka波段ARM天顶雷达（Ka-band ARM Zenith Radar, KAZR）衍生降水数据：Matrosov等人，2022（https://doi.org/10.1525/elementa.2021.00101） - 基于累积量估算的伪降水数据：Raphael等人，2024（https://doi.org/10.1525/elementa.2023.00040） - 夏季降水数据：Smith等人，2024（https://doi.org/10.5194/egusphere-2024-1977） 已知问题： 以下为已知问题，将在后续数据集版本中予以修复： 1. 数据记录中仍存在约7%的剩余间隙（详见附录） 2. 当前测量数据格式（Measurement Data Format, MDF）未包含逐点数据源字段 3. 2020年5月15日—6月19日的航次人员交接航段（第3—4航段）无降水数据。