ERA5 hourly data on single levels from 1940 to present

ERA5 is the fifth generation ECMWF reanalysis for the global climate and weather for the past 8 decades. Data is available from 1940 onwards. ERA5 replaces the ERA-Interim reanalysis.
Reanalysis combines model data with observations from across the world into a globally complete and consistent dataset using the laws of physics. This principle, called data assimilation, is based on the method used by numerical weather prediction centres, where every so many hours (12 hours at ECMWF) a previous forecast is combined with newly available observations in an optimal way to produce a new best estimate of the state of the atmosphere, called analysis, from which an updated, improved forecast is issued. Reanalysis works in the same way, but at reduced resolution to allow for the provision of a dataset spanning back several decades. Reanalysis does not have the constraint of issuing timely forecasts, so there is more time to collect observations, and when going further back in time, to allow for the ingestion of improved versions of the original observations, which all benefit the quality of the reanalysis product.

ERA5是第五代欧洲中期天气预报中心（ECMWF）再分析数据集，用于覆盖过去80年的全球气候与天气研究。其数据可获取时段始于1940年。ERA5取代了此前的ERA-Interim再分析数据集。
再分析技术依托物理定律，将数值模式数据与全球各地的观测数据整合为一套完整一致的全球数据集，这一过程被称为数据同化（data assimilation）。该方法借鉴了数值天气预报业务中心的作业流程：每隔固定时长（欧洲中期天气预报中心为12小时），将前期预报结果与最新获取的观测资料以最优方式融合，得到当前大气状态的最佳估计值（即分析场），并基于此生成更新优化后的预报产品。再分析的工作原理与此一致，但为了支撑数十年跨度的长时序数据集构建，其空间分辨率有所降低。此外，再分析无需受实时预报的时效约束，因此可获得更充足的时间来收集观测数据；在回溯更早的历史时段时，还可对原始观测资料进行版本优化后再纳入分析，这一系列举措均有助于提升再分析产品的质量。

搜集汇总

背景与挑战

背景概述

ERA5是ECMWF第五代全球气候和天气再分析数据集，提供1940年至今每小时的大气、海洋波浪和地表变量估计值。该数据集通过数据同化技术结合模型和观测数据，生成全球一致的高分辨率(0.25度)数据集，适用于广泛的气候研究应用。