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Table 1: Main variables and note on adjustments Anchor table1 table1
Origin | Variable | Units | Time period for | Time period for | Base line period for | Adjustments |
ERA5 | 0-7cm volumetric soil moisture | m3m-3 | 1979 - present | 1979 - present | 1981-2010 | Yes, see here |
ERA5 | Total precipitation | m day-1 | 1979 - present | 1979 - present | 1981-2010 | No |
ERA5 | Sea-ice cover | (0 - 1) | 1979 - present | 1979 - present | 1981-2010 | No |
ERA5 | Surface air relative humidity | % | 1979 - present | 1979 - present | 1981-2010 | No |
ERA5 | Surface air temperature | K | 1979 - present | 1979 - present | 1981-2010 | Yes, see here |
ERA-Interim | 0-7cm volumetric soil moisture | m3m-3 | 1979 - present | 1979 - present | 1981-2010 | Yes, see here |
ERA-Interim | Total precipitation | m day-1 | 1979 - present | 1979 - present | 1981-2010 | No |
ERA-Interim | Sea-ice cover | (0 - 1) | 1979 - present | 1979 - present | 1981-2010 | No |
ERA-Interim | Surface air relative humidity | % | 1979 - present | 1979 - present | 1981-2010 | Yes, see here |
ERA-Interim | Surface air temperature | K | 1979 - present | 1979 - present | 1981-2010 | Yes, see here |
ERA5
Surface air temperature Anchor era5surftempadj era5surftempadj
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Table 2: Information about GRIB codes, version numbers and differences between version numbers.
Origin | Variable | GRIB | Grid | Version number | Difference between v01 | Difference between |
ERA5 | 0-7cm volumetric soil moisture | 39 | .25/.25 | v02 | 12 m running mean statistics reprocessed | |
ERA5 | Total precipitation | 228 | .25/.25 | v02 | 12 m running mean statistics reprocessed | |
ERA5 | Sea-ice cover | 31 | .25/.25 | v02 | 12 m running mean statistics reprocessed | |
ERA5 | Surface air relative humidity | 157 | .25/.25 | v02 | 12 m running mean statistics reprocessed | |
ERA5 | Surface air temperature | 167 | .25/.25 | v02 | Reprocessing adjustment over Great Lakes only, updated interpolation package for regridding to regular grid.* 12 m running mean statistics reprocessed | |
ERA-Interim | 0-7cm volumetric soil moisture | 39 | .25/.25 | v02/v03 | Applied masking over sea, ice sheets and deserts; | 12 m running mean statistics reprocessed |
ERA-Interim | Total precipitation | 228 | .25/.25 | v02/v03 | Grid changed to regular | 12 m running mean statistics reprocessed |
ERA-Interim | Sea-ice cover | 31 | .25/.25 | v02/v03 | Grid changed to .25/.25 | 12 m running mean statistics reprocessed |
ERA-Interim | Surface air | 157 | .25/.25 | v02/v03 | Grid changed to regular; GRIB code changed | 12 m running mean statistics reprocessed |
ERA-Interim | Surface air temperature | 167 | .25/.25 | v02/03 | Adjustments over ice-free seas applied; GRIB code changed | 12 m running mean statistics reprocessed |
Known issues
- Update from v01 to v02 of ERA5 surface air temperature:
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"Essential climate variables for assessment of climate variability from 1979 to present" constitutes the basis for the C3S monthly Climate Bulletin. For the months of September, October, November and December 2021, erroneously large values of soil moisture, and to a lesser extent, of 2m temperature and of humidity became noticeable in the timely ERA5 product (ERA5T) for central Asia. A full description of the issue and how it has been addressed can be found here.
After correction, the timely published "Essential climate variables for assessment of climate variability from 1979 to present" have been replaced for each of the affected months with a newly post-processed version based on the corrected, consolidated ERA5 (rather than ERA5T, which bore the erroneous values). Graphics and time-series data of the monthly climate bulletin have been accordingly updated and replaced for the affected months in the respective bulletin. The table of the bottom of the page outlines which months have been updated to date.
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The outdated and new maps of hydrological variables for Europe for October highlight the main difference between the dataset containing the erroneous values and the new one based on the consolidated ERA5. The issue is very apparent in Central Asia in the soil moisture maps and, to some extent, for the other variables too.
| Old erroneous | New corrected |
|---|---|
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Figure 1: Anomalies in precipitation, the relative humidity of surface air, the volumetric moisture content of the top 7 cm of soil and surface air temperature for October 2021 with respect to October averages for the period 1991-2020. The darker grey shading denotes where soil moisture is not shown due to ice cover or climatologically low precipitation. Data source: Left ERA5T (erroneous), Right: ERA5 consolidated (new & corrected) Credit: Copernicus Climate Change Service/ECMWF.
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Table 3: Original erroneous and the new corrected versions of data and graphics.Anchor table3 table3
| September | October | November | December | |
|---|---|---|---|---|
| Old erroneous | Zip-file of data and graphics (1981-2010, 1991-2020) | Zip-file of data and graphics (1981-2010, 1991-2020) | ||
| New corrected graphics and time-series data | September monthly summary | November monthly summary | Not yet updated | |
| Corrected spatial data available in the CDS entry? | yes | yes | yes | no |
| Date of correction | 07/01/2022 | 07/01/2022 | 07/01/2022 | TBD |
| Anchor | ||||
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