This article highlights major differences between ERA-Interim and ERA5 but is not exhaustive. In particular changes to the computation of individual atmospheric parameters (due to the change in the assimilation system from 31r2 to 41r2) are not listed here.
Changes for all ERA5 datasets
| ERA-Interim | ERA5 | |
|---|---|---|
| Period covered | 1979 - present | 1979 - present |
| Production Period | August 2006 – end 2018 | Jan 2016 – end 2017, then continued in near real-time |
| Assimilation system | IFS Cycle 31r2 4D-Var | IFS Cycle 41r2 4D-Var |
| Model input | As in operations (inconsistent SST) | Appropriate for climate (e.g. CMIP5 greenhouse gases, volcanic eruptions, SST and sea-ice cover) |
| Input observations | As in ERA-40 and from Global Telecommunication System | In addition, various newly reprocessed datasets and recent instruments that could not be ingested in ERA-Interim |
| Variational bias scheme | Satellite radiances | Also ozone, aircraft and surface pressure data |
| Satellite data | RTTOV-7, clear-sky, 1D-VAR rainy radiances | RTTOV-11, all-sky for various components |
| New parameters | tbd | |
| Parameters removed | tbd | |
| Handling of accumulated parameters | Accumulated from the beginning of the forecast | Accumulated from previous post-processing Does this mean from beginning of the Step? |
| Product main page | http://www.ecmwf.int/en/research/climate-reanalysis/era-interim | http://climate.copernicus.eu/climate-reanalysis |
| Technical documentation | Berrisford et al 2011: The ERA-Interim archive Version 2.0 | ERA5 data documentation |
| Additional innovations | Long-term evolution of CO2 in RTTOV, cell-pressure correction SSU, improved bias correction for radiosondes, EDA perturbations for sea-ice cover |
Changes for daily dataset
| ERA-Interim | ERA5 | |
|---|---|---|
| Spatial resolution | 79 km globally, 60 levels to 0.1 hPa | 31 km globally, 137 levels to 0.01 hPa |
| Output frequency (temporal resolution) | 6-hourly analysis, 3-hourly forecast fields | Hourly analysis and forecast fields, 3-hourly for the Ensemble of Data Assimilations (EDA) |
| Uncertainty estimates | None | From a 10-member Ensemble of Data Assimilations (EDA) at 63 km resolution |
| Additional innovations | Long-term evolution of CO2 in RTTOV, cell-pressure correction SSU, improved bias correction for radiosondes, EDA perturbations for sea-ice cover | |
New parameters:
| ||
Parameters removed:
|
Changes for temporal aggregation sets
| ERA-Interim | ERA5 | |
|---|---|---|
