ERA5 monthly averaged data on pressure 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 provides hourly estimates for a large number of atmospheric, ocean-wave and land-surface quantities.
An uncertainty estimate is sampled by an underlying 10-member ensemble
at three-hourly intervals. Ensemble mean and spread have been pre-computed for convenience.
Such uncertainty estimates are closely related to the information content of the available observing system which
has evolved considerably over time. They also indicate flow-dependent sensitive areas.
To facilitate many climate applications, monthly-mean averages have been pre-calculated too,
though monthly means are not available for the ensemble mean and spread.
ERA5 is updated daily with a latency of about 5 days (monthly means are available around the 6th of each month). In case that serious flaws are detected in this early release (called ERA5T), this data could be different from the final release 2 to 3 months later. So far this has only been the case for the month September 2021, while it will also be the case for October, November and December 2021. For months prior to September 2021 the final release has always been equal to ERA5T, and the goal is to align the two again after December 2021.
ERA5 is updated daily with a latency of about 5 days (monthly means are available around the 6th of each month). In case that serious flaws are detected in this early release (called ERA5T), this data could be different from the final release 2 to 3 months later. In case that this occurs users are notified.
The data set presented here is a regridded subset of the full ERA5 data set on native resolution.
It is online on spinning disk, which should ensure fast and easy access.
It should satisfy the requirements for most common applications.
An overview of all ERA5 datasets can be found in this article.
Information on access to ERA5 data on native resolution is provided in these guidelines.
Data has been regridded to a regular lat-lon grid of 0.25 degrees for the reanalysis and 0.5 degrees for
the uncertainty estimate (0.5 and 1 degree respectively for ocean waves).
There are four main sub sets: hourly and monthly products, both on pressure levels (upper air fields) and single levels (atmospheric, ocean-wave and land surface quantities).
The present entry is "ERA5 monthly mean data on pressure levels from 1940 to present".

ERA5系欧洲中期天气预报中心（ECMWF）针对过去八十年全球气候与天气的第五代再分析产品。数据自1940年起可追溯。ERA5取代了先前的ERA-Interim再分析产品。再分析技术通过将模型数据与全球范围内的观测数据相结合，运用物理定律构建了一个全球性完整且一致的观测数据集。这一原理被称为数据同化，其方法借鉴了数值天气预报中心的做法，即每隔数小时（在ECMWF为12小时）将前一次预测与新的观测数据以最优方式合并，以生成新的最佳大气状态估计，即分析，进而发布更新、改进的预测。再分析以较低的分辨率进行，以便提供涵盖数十年历史的数据集。由于再分析不受及时发布预报的约束，因此有更多时间收集观测数据，并在追溯至更早时间时，允许摄入原始观测数据的改进版本，从而全面提升再分析产品的质量。ERA5提供了大量大气、海洋波浪和地表量的每小时估计值。通过底层10成员集合在每三小时采样一次的不确定性估计。为了方便，已预先计算了集合平均和离散度。此类不确定性估计与可用观测系统的信息含量密切相关，并随时间演变而显著发展。它们还指示了与流动相关的敏感区域。为了便利众多气候应用，已预先计算了月平均数，尽管集合平均和离散度的月平均值不可用。ERA5每日更新，滞后约5天（月平均值通常在每月的6日左右可用）。如果在早期发布版（称为ERA5T）中发现严重缺陷，则这些数据可能与两个月后发布的最终版本2至3个月后的版本不同。迄今为止，这种情况仅发生在2021年9月，而10月、11月和12月2021年也将出现这种情况。对于2021年9月之前月份的最终发布版始终等于ERA5T，目标是在2021年12月之后再次使两者一致。ERA5每日更新，滞后约5天（月平均值通常在每月的6日左右可用）。如果在早期发布版（称为ERA5T）中发现严重缺陷，则这些数据可能与两个月后发布的最终版本2至3个月后的版本不同。如果发生这种情况，用户将收到通知。此处展示的数据集是全ERA5数据集在原生分辨率上的重网格子集。它存储在旋转磁盘中，这应确保快速且易于访问。它应满足大多数常见应用的要求。所有ERA5数据集的概述可在此篇文章中找到。关于访问原生分辨率ERA5数据的指南提供在这些指导方针中。数据已重网格到0.25度（用于再分析）和0.5度（用于不确定性估计）（分别为0.5度和1度，用于海洋波浪）的规则经纬度网格。存在四个主要子集：小时和月度产品，包括压力层（高空场）和单层（大气、海洋波浪和地表量）。本条目为“1940年至现在的ERA5压力层月平均数据”。

搜集汇总

背景与挑战

背景概述

ERA5月平均气压层数据集是ECMWF第五代全球气候和天气再分析数据，覆盖1940年至今，通过数据同化技术提供高分辨率和一致性的全球气候数据。数据集包含月平均气压层数据，适用于气候研究，每日更新并具有约5天的延迟。