ERA5 Reanalysis Model Level Data

After many years of research and technical preparation, the production of a new ECMWF climate reanalysis to replace ERA-Interim is in progress. ERA5 is the fifth generation of ECMWF atmospheric reanalyses of the global climate, which started with the FGGE reanalyses produced in the 1980s, followed by ERA-15, ERA-40 and most recently ERA-Interim. ERA5 will cover the period January 1950 to near real time.ERA5 is produced using high-resolution forecasts (HRES) at 31 kilometer resolution (one fourth the spatial resolution of the operational model) and a 62 kilometer resolution ten member 4D-Var ensemble of data assimilation (EDA) in CY41r2 of ECMWF's Integrated Forecast System (IFS) with 137 hybrid sigma-pressure (model) levels in the vertical, up to a top level of 0.01 hPa. Atmospheric data on these levels are interpolated to 37 pressure levels (the same levels as in ERA-Interim). Surface or single level data are also available, containing 2D parameters such as precipitation, 2 meter temperature, top of atmosphere radiation and vertical integrals over the entire atmosphere. The IFS is coupled to a soil model, the parameters of which are also designated as surface parameters, and an ocean wave model. Generally, the data is available at an hourly frequency and consists of analyses and short (12 hour) forecasts, initialized twice daily from analyses at 06 and 18 UTC. Most analyses parameters are also available from the forecasts. There are a number of forecast parameters, for example mean rates and accumulations, that are not available from the analyses.Improvements to ERA5, compared to ERA-Interim, include use of HadISST.2, reprocessed ECMWF climate data records (CDR), and implementation of RTTOV11 radiative transfer. Variational bias corrections have not only been applied to satellite radiances, but also ozone retrievals, aircraft observations, surface pressure, and radiosonde profiles.Please note: DECS is producing a CF 1.6 compliant netCDF-4/HDF5 version of ERA5 for the CISL RDA at NCAR. The netCDF-4/HDF5 version is the default RDA ERA5 online data format.

经过多年的研究与技术筹备，用于替代ERA-Interim的全新欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts, ECMWF)气候再分析数据集已进入制作阶段。ERA5是ECMWF第五代全球大气气候再分析产品，其沿革可追溯至20世纪80年代推出的FGGE再分析数据，后续依次推出了ERA-15、ERA-40，最新一代则为ERA-Interim。ERA5的时间覆盖范围为1950年1月至近实时时段。该数据集基于ECMWF集成预报系统(Integrated Forecast System, IFS)CY41r2版本的两套核心方案生成：一是分辨率达31公里的高分辨率预报场(High-Resolution Forecast, HRES，仅为业务模式空间分辨率的1/4)；二是分辨率62公里、包含10个成员的四维变分集合数据同化(Ensemble Data Assimilation, EDA)系统。其垂直方向共设137层混合σ-气压模式层，顶层气压低至0.01百帕(hPa)。各垂直层的大气数据会被插值至37个气压层（与ERA-Interim采用的气压层一致）。同时提供地表（单一层）数据，涵盖降水、2米气温、大气顶辐射以及整层大气垂直积分等二维参数。IFS耦合了土壤模式与海浪模式，其中土壤模式的相关参数也被归类为地表参数。总体而言，数据集以小时为时间分辨率，包含分析场与短期（12小时）预报场两类数据：预报场每日基于世界协调时(Coordinated Universal Time, UTC)06时与18时的分析场初始化两次。多数分析场参数可从预报场中获取，但部分仅支持预报输出的参数（如平均速率与累积量）无法从分析场中获得。相较于ERA-Interim，ERA5的改进之处包括：采用了HadISST.2数据集、重新处理的ECMWF气候数据记录(Climate Data Records, CDR)，以及引入了RTTOV11辐射传输模型。变分偏差校正不仅应用于卫星辐射率数据，还覆盖了臭氧反演、飞机观测、地表气压以及无线电探空廓线数据。请注意：美国国家大气研究中心(National Center for Atmospheric Research, NCAR)计算与信息系统实验室(Computational and Information Systems Laboratory, CISL)研究数据档案(Research Data Archive, RDA)项目组，正针对ERA5数据集制作符合气候与预报元数据标准(Climate and Forecast Metadata Standard, CF)1.6版本的netCDF-4/HDF5格式版本，该格式为RDA平台上ERA5在线数据的默认格式。

搜集汇总

背景与挑战

背景概述

ERA5 Reanalysis Model Level Data是ECMWF提供的高分辨率全球气候再分析数据集，覆盖1950年至近实时，包含137个垂直层次的大气数据，适用于气候和气象研究。