HadUK-Grid Gridded Climate Observations on a 25km grid over the UK, v1.3.0.ceda (1836-2023)

HadUK-Grid is a collection of gridded climate variables derived from the network of UK land surface observations. The data have been interpolated from meteorological station data onto a uniform grid to provide complete and consistent coverage across the UK. The dataset at 25 km resolution is derived from the associated 1 km x 1 km resolution to allow for comparison to data from UKCP18 climate projections. The dataset spans the period from 1836 to 2023, but the start time is dependent on climate variable and temporal resolution.

The gridded data are produced for daily, monthly, seasonal and annual timescales, as well as long term averages for a set of climatological reference periods. Variables include air temperature (maximum, minimum and mean), precipitation, sunshine, mean sea level pressure, wind speed, relative humidity, vapour pressure, days of snow lying, and days of ground frost.

This data set supersedes the previous versions of this dataset which also superseded UKCP09 gridded observations. Subsequent versions may be released in due course and will follow the version numbering as outlined by Hollis et al. (2018, see linked documentation).

The changes for v1.3.0.ceda HadUK-Grid datasets are as follows:

* Added data for calendar year 2023

* Added newly digitised data for daily rainfall (62 Scottish stations for 1945-1960)

* Daily rainfall data for Bolton, 1916-1919 have been corrected (previous values were corrupted and needed redigitising)

* Daily rainfall data for Buxton, 1960 have been corrected (conversion from inches to mm had been applied incorrectly)

* Rainfall data from EA and SEPA APIs are included for the last three months of the dataset (Oct-Dec 2023) (for all earlier months the rainfall data from partner agencies is obtained from the Met Office's MIDAS database)

* The number of stations used for groundfrost, sunshine and windspeed have reduced at different points in the historical series when comparing v1.3.0.ceda to the previous version v1.2.0.ceda. These reductions in station numbers have been caused by changes made in the data processing steps upstream of the gridding process.

* For groundfrost this reduction has been caused by an automated quality control process flagging the historical data which have been removed as suspect (mostly affecting data from 1961 to 1970).

* For sunshine the small reduction in the 1960s has been caused by the removal of digitized monthly sunshine data through this period where we wish to reverify the data source.

* For windspeed the reduction from 1969 to 2010 has been caused by changes to rules applied relating to data completeness when compiling daily mean windspeeds, which in turn have followed through to monthly statistics.

* We plan to carry out a review of the data which have been excluded from this version. Some of it may be reintroduced in a future release.

* Net changes to the input station data:

- Total of 126970983 observations
- 125384735 (98.75%) unchanged
- 28487 (0.02%) modified for this version
- 1557761 (1.23%) added in this version
- 188522 (0.15%) deleted from this version

The primary purpose of these data are to facilitate monitoring of UK climate and research into climate change, impacts and adaptation. The datasets have been created by the Met Office with financial support from the Department for Business, Energy and Industrial Strategy (BEIS) and Department for Environment, Food and Rural Affairs (DEFRA) in order to support the Public Weather Service Customer Group (PWSCG), the Hadley Centre Climate Programme, and the UK Climate Projections (UKCP18) project. The output from a number of data recovery activities relating to 19th and early 20th Century data have been used in the creation of this dataset, these activities were supported by: the Met Office Hadley Centre Climate Programme; the Natural Environment Research Council project "Analysis of historic drought and water scarcity in the UK"; the UK Research & Innovation (UKRI) Strategic Priorities Fund UK Climate Resilience programme; The UK Natural Environment Research Council (NERC) Public Engagement programme; the National Centre for Atmospheric Science; National Centre for Atmospheric Science and the NERC GloSAT project; and the contribution of many thousands of public volunteers. The dataset is provided under Open Government Licence.

HadUK-Grid是一套基于英国陆地表面观测网络构建的格点气候变量数据集。该数据将气象站观测数据插值至统一格点，以实现英国全境完整且一致的覆盖。其25千米分辨率版本由配套的1千米×1千米分辨率数据衍生得到，以便与UKCP18气候投影数据进行比对。数据集的时间跨度为1836年至2023年，但起始年份因气候变量与时间分辨率的不同而有所差异。

该格点数据涵盖日、月、季、年多个时间尺度，同时包含一套气候基准期的长期平均值。变量包括气温（最高温、最低温与平均温）、降水量、日照时数、平均海平面气压、风速、相对湿度、水汽压、积雪日数与地面霜日数。

本数据集替代了此前的版本，而此前版本亦替代了UKCP09格点观测数据集。后续版本将适时发布，并将遵循Hollis等人（2018年，详见关联文档）所概述的版本编号规则。

v1.3.0.ceda版HadUK-Grid数据集的更新内容如下：
* 新增2023日历年的观测数据
* 新增1945-1960年苏格兰62个气象站的每日降水数字化新数据
* 修正博尔顿1916-1919年的每日降水数据（此前数据损坏，需重新数字化）
* 修正巴克斯顿1960年的每日降水数据（此前英寸转毫米的换算操作有误）
* 数据集最后三个月（2023年10-12月）采用环境署（EA）与苏格兰环境保护局（SEPA）API提供的降水数据；此前所有月份的降水数据均来自合作机构提供的英国气象局（Met Office）MIDAS数据库数据源
* 相较于v1.2.0.ceda版本，v1.3.0.ceda版本在历史序列的不同节点上，用于地面霜日、日照时数与风速计算的气象站数量有所减少。该变化源于格点化流程上游的数据处理步骤调整
* 地面霜日数据的站数缩减，源于自动化质量控制流程将部分历史数据标记为可疑数据并移除，该影响主要集中在1961-1970年的数据
* 日照时数数据在1960年代的小幅缩减，源于该时段的数字化月日照数据被移除，以便重新核验数据源
* 风速数据在1969-2010年的站数缩减，源于每日平均风速统计时的数据完整性规则调整，该调整亦传导至月度统计数据
* 我们计划对本版本中被排除的数据开展复核，部分数据或将在后续版本中重新纳入
* 输入站观测数据的净变化情况如下：
- 总观测条数：126970983条
- 125384735条（98.75%）未发生变更
- 28487条（0.02%）在本版本中被修改
- 1557761条（1.23%）在本版本中新增
- 188522条（0.15%）在本版本中被删除

本数据集的核心用途为支撑英国气候监测以及气候变化、影响与适应相关研究。该数据集由英国气象局（Met Office）研发，获得商业、能源与产业战略部（BEIS）以及环境、食品与农村事务部（DEFRA）的经费支持，以服务于公共气象服务客户组（PWSCG）、哈德利中心气候计划以及英国气候投影（UKCP18）项目。本数据集的构建还纳入了多项针对19世纪与20世纪早期数据的复苏工作成果，相关工作得到以下机构与项目的支持：英国气象局哈德利中心气候计划；英国自然环境研究理事会“英国历史干旱与水资源短缺分析”项目；英国研究与创新署（UKRI）战略优先基金英国气候韧性计划；英国自然环境研究理事会（NERC）公众参与项目；国家大气科学中心；国家大气科学中心与NERC GloSAT项目；此外还有数千名公众志愿者的贡献。本数据集采用开放政府许可（Open Government Licence）进行发布。