HadISDH land: gridded global monthly land surface humidity data version 4.2.0.2019f

This is the 4.2.0.2019f version of the HadISDH (Integrated Surface Database Humidity) land data. These data are provided by the Met Office Hadley Centre. This version spans 1/1/1973 to 31/12/2019. The data are monthly gridded (5 degree by 5 degree) fields. Products are available for temperature and six humidity variables: specific humidity (q), relative humidity (RH), dew point temperature (Td), wet bulb temperature (Tw), vapour pressure (e), dew point depression (DPD). Data are provided in either NetCDF or ASCII format. This version extends the 4.1.0.2018f version to the end of 2019 and constitutes a minor update to HadISDH due to changing some of the code base from IDL to Python 3 and detecting and fixing various bugs in the process. These have led to small changes in regional and global average values and coverage. All other processing steps for HadISDH remain identical. Users are advised to read the update document in the Docs section for full details. As in previous years, the annual scrape of NOAA’s Integrated Surface Dataset for HadISD.3.1.0.2019f, which is the basis of HadISDH.land, has pulled through some historical changes to stations. This, and the additional year of data, results in small changes to station selection. There has been an issue with data for April 2015 whereby it is missing for most of the globe. This will hopefully be resolved by next year’s update. The homogeneity adjustments differ slightly due to sensitivity to the addition and loss of stations, historical changes to stations previously included and the additional 12 months of data. To keep informed about updates, news and announcements follow the HadOBS team on twitter @metofficeHadOBS. For more detailed information e.g bug fixes, routine updates and other exploratory analysis, see the HadISDH blog: http://hadisdh.blogspot.co.uk/ References: When using the dataset in a paper please cite the following papers (see Docs for link to the publications) and this dataset (using the "citable as" reference): Willett, K. M., Dunn, R. J. H., Thorne, P. W., Bell, S., de Podesta, M., Parker, D. E., Jones, P. D., and Williams Jr., C. N.: HadISDH land surface multi-variable humidity and temperature record for climate monitoring, Clim. Past, 10, 1983-2006, doi:10.5194/cp-10-1983-2014, 2014. Dunn, R. J. H., et al. 2016: Expanding HadISD: quality-controlled, sub-daily station data from 1931, Geoscientific Instrumentation, Methods and Data Systems, 5, 473-491. Smith, A., N. Lott, and R. Vose, 2011: The Integrated Surface Database: Recent Developments and Partnerships. Bulletin of the American Meteorological Society, 92, 704–708, doi:10.1175/2011BAMS3015.1 We strongly recommend that you read these papers before making use of the data, more detail on the dataset can be found in an earlier publication: Willett, K. M., Williams Jr., C. N., Dunn, R. J. H., Thorne, P. W., Bell, S., de Podesta, M., Jones, P. D., and Parker D. E., 2013: HadISDH: An updated land surface specific humidity product for climate monitoring. Climate of the Past, 9, 657-677, doi:10.5194/cp-9-657-2013.

本数据集为HadISDH（Integrated Surface Database Humidity，集成地表湿度数据集）陆地数据的4.2.0.2019f版本，由英国气象局哈德利中心（Met Office Hadley Centre）提供。
该版本的数据时间跨度为1973年1月1日至2019年12月31日。
数据为月度5°×5°网格化场。
可获取的产品涵盖气温及6类湿度变量：比湿（specific humidity, q）、相对湿度（relative humidity, RH）、露点温度（dew point temperature, Td）、湿球温度（wet bulb temperature, Tw）、水汽压（vapour pressure, e）以及露点差（dew point depression, DPD）。
数据提供NetCDF与ASCII两种格式。
本版本将此前的4.1.0.2018f版本的数据时限延伸至2019年末，同时针对HadISDH进行了小幅更新：将部分代码库从IDL迁移至Python 3，并在开发过程中检测并修复了若干漏洞。上述调整使得区域与全球平均值及数据覆盖范围产生了小幅变化。HadISDH其余所有处理流程均保持不变。
建议用户查阅Docs板块中的更新文档以获取完整细节。
与往年一致，本次针对构建HadISDH.land基础的HadISD.3.1.0.2019f版本的NOAA集成地表数据集（Integrated Surface Dataset）年度抓取操作，已纳入部分站点的历史变更信息。受此影响，加上新增的一年数据，站点选择方案出现了小幅调整。
2015年4月的数据存在一项已知问题：全球大部分区域该月数据缺失。我们有望在次年的更新中修复该问题。
由于对站点增减、既往纳入站点的历史变更以及新增的12个月数据存在敏感性，数据的均一性调整存在小幅差异。
如需获取更新、新闻及公告相关资讯，请关注Twitter上的HadOBS团队账号@metofficeHadOBS。
如需获取更多详细信息，例如漏洞修复详情、常规更新内容及其他探索性分析，请访问HadISDH博客：http://hadisdh.blogspot.co.uk/
参考文献：若在学术论文中使用本数据集，请引用如下文献（文献链接详见Docs板块）及本数据集的可引用标注：
Willett, K. M., Dunn, R. J. H., Thorne, P. W., Bell, S., de Podesta, M., Parker, D. E., Jones, P. D., 及Williams Jr., C. N.：《用于气候监测的HadISDH陆地多变量湿度与气温记录》，Clim. Past（气候往事），10，1983-2006，doi:10.5194/cp-10-1983-2014，2014。
Dunn, R. J. H. 等，2016：《扩展HadISD：1931年起的质量受控逐小时站点数据》，Geoscientific Instrumentation, Methods and Data Systems（地球科学仪器、方法与数据系统），5，473-491。
Smith, A., N. Lott, 及R. Vose，2011：《集成地表数据集：最新进展与合作项目》，Bulletin of the American Meteorological Society（美国气象学会公报），92，704–708，doi:10.1175/2011BAMS3015.1。
我们强烈建议用户在使用本数据集前查阅上述文献，有关本数据集的更多详细信息可参阅早前发表的论文：Willett, K. M., Williams Jr., C. N., Dunn, R. J. H., Thorne, P. W., Bell, S., de Podesta, M., Jones, P. D., 及Parker D. E.，2013：《HadISDH：用于气候监测的更新版陆地比湿产品》，Climate of the Past（气候往事），9，657-677，doi:10.5194/cp-9-657-2013。