Daily histograms of wind speed (100m), wind direction (100m) and atmospheric stability derived from ERA5

This dataset contains daily histograms of wind speed at 100m ("WS100"), wind direction at 100 m ("WD100") and an atmospheric stability proxy ("STAB") derived from the ERA5 hourly data on single levels [1] accessed via the Copernicus Climate Change Climate Data Store [2]. The dataset covers six geographical regions (illustrated in regions.png) on a reduced 0.5 x 0.5 degrees regular grid and covers the period 1994 to 2023 (both years included). The dataset is packaged as a zip folder per region which contains a range of monthly zip folders following the convention of zarr ZipStores (more details here: https://zarr.readthedocs.io/en/stable/api/storage.html). Thus, the monthly zip folders are intended to be used in connection with the xarray python package (no unzipping of the monthly files needed).Wind speed and wind direction are derived from the U- and V-components. The stability metric makes use of a 5-class classification scheme [3] based on the Obukhov length whereby the required Obukhov length was computed using [4]. The following bins (left edges) have been used to create the histograms:Wind speed: [0, 40) m/s (bin width 1 m/s)<br>Wind direction: [0,360) deg (bin width 15 deg)<br>Stability: 5 discrete stability classes (1: very unstable, 2: unstable, 3: neutral, 4: stable, 5: very stable)<br><b>Main Purpose:</b> The dataset serves as minimum input data for the CLIMatological REPresentative PERiods (climrepper) python package (https://gitlab.windenergy.dtu.dk/climrepper/climrepper) in preparation for public release).<br>References:<br>[1] Hersbach, H., Bell, B., Berrisford, P., Biavati, G., Horányi, A., Muñoz Sabater, J., Nicolas, J., Peubey, C., Radu, R., Rozum, I., Schepers, D., Simmons, A., Soci, C., Dee, D., Thépaut, J-N. (2023): ERA5 hourly data on single levels from 1940 to present. Copernicus Climate Change Service (C3S) Climate Data Store (CDS), DOI: 10.24381/cds.adbb2d47 (Accessed Nov. 2024)<br>[2] Copernicus Climate Change Service, Climate Data Store, (2023): ERA5 hourly data on single levels from 1940 to present. Copernicus Climate Change Service (C3S) Climate Data Store (CDS), DOI: 10.24381/cds.adbb2d47 (Accessed Nov. 2024)'<br><br>[3] Holtslag, M. C., Bierbooms, W. A. A. M., &amp; Bussel, G. J. W. van. (2014). Estimating atmospheric stability from observations and correcting wind shear models accordingly. In Journal of Physics: Conference Series (Vol. 555, p. 012052). IOP Publishing. https://doi.org/10.1088/1742-6596/555/1/012052<br>[4] Copernicus Knowledge Base, ERA5: How to calculate Obukhov Length, URL: https://confluence.ecmwf.int/display/CKB/ERA5:+How+to+calculate+Obukhov+Length, last accessed: Nov 2024<br>

本数据集包含100米高度风速（WS100）、100米高度风向（WD100）以及大气稳定性代理指标（STAB）的逐日直方图，上述数据源自通过哥白尼气候变化服务气候数据存储库获取的ERA5单层逐时数据集[1]。
本数据集覆盖6个地理区域（区域分布详见regions.png），采用缩减后的0.5°×0.5°规则网格，时间跨度为1994年至2023年（包含首尾两年）。
本数据集按区域打包为压缩文件夹，每个区域文件夹内包含若干按月份命名的压缩文件夹，遵循zarr压缩存储库（ZipStores）的规范（详细说明参见：https://zarr.readthedocs.io/en/stable/api/storage.html）。因此，月度压缩文件夹可直接与Python的xarray库配合使用，无需提前解压月度文件。
风速与风向数据由U、V分量推导得到。稳定性指标采用基于奥布霍夫长度（Obukhov length）的5级分类体系[3]，所需的奥布霍夫长度通过文献[4]的方法计算得到。
本次直方图构建采用以下分箱（左边界）规则：
- 风速：[0, 40) m/s，箱宽为1 m/s
- 风向：[0, 360) deg，箱宽为15 deg
- 稳定性：5个离散稳定性等级（1：极不稳定，2：不稳定，3：中性，4：稳定，5：极稳定）
<b>主要用途：</b>本数据集作为即将公开发布的气候代表性时段（CLIMREPPER，简称climrepper）Python库（https://gitlab.windenergy.dtu.dk/climrepper/climrepper）的最小输入数据集。
参考文献：
[1] Hersbach, H., Bell, B., Berrisford, P., Biavati, G., Horányi, A., Muñoz Sabater, J., Nicolas, J., Peubey, C., Radu, R., Rozum, I., Schepers, D., Simmons, A., Soci, C., Dee, D., Thépaut, J-N. (2023): 1940年至今的ERA5单层逐时数据集. 哥白尼气候变化服务（C3S）气候数据存储库（CDS）, DOI: 10.24381/cds.adbb2d47（2024年11月访问）
[2] Copernicus Climate Change Service, Climate Data Store. (2023): 1940年至今的ERA5单层逐时数据集. 哥白尼气候变化服务（C3S）气候数据存储库（CDS）, DOI: 10.24381/cds.adbb2d47（2024年11月访问）
[3] Holtslag, M. C., Bierbooms, W. A. A. M., van Bussel, G. J. W. (2014). 基于观测资料估算大气稳定性并修正风切变模型. 见《物理学报：会议系列》（第555卷，第012052页）. IOP出版社. https://doi.org/10.1088/1742-6596/555/1/012052
[4] 哥白尼知识库，ERA5：奥布霍夫长度计算方法，网址：https://confluence.ecmwf.int/display/CKB/ERA5:+How+to+calculate+Obukhov+Length，最后访问时间：2024年11月