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Table 1: WFDE5 variables summaryAnchor table1 table1
Variable name | Description | Units | Time coverage (v1.0, v1.1) | Time coverage (v2.0) |
Wind | Near-surface wind speed | m s-1 | 1979-01-01 00:00:00 to 2018-12-31 23:00:00 | 1979-01-01 00:00:00 to 2019-12-31 23:00:00 |
Tair | Near-surface air temperature | K | 1979-01-01 00:00:00 to 2018-12-31 23:00:00 | 1979-01-01 00:00:00 to 2019-12-31 23:00:00 |
PSurf | Surface air pressure | Pa | 1979-01-01 00:00:00 to 2018-12-31 23:00:00 | 1979-01-01 00:00:00 to 2019-12-31 23:00:00 |
Qair | Near-surface specific humidity | kg kg-1 | 1979-01-01 00:00:00 to 2018-12-31 23:00:00 | 1979-01-01 00:00:00 to 2019-12-31 23:00:00 |
LWdown | Surface downwelling longwave radiation | W m-2 | 1979-01-01 07:00:00 to 2018-12-31 23:00:00 | 1979-01-01 07:00:00 to 2019-12-31 23:00:00 |
SW down | Surface downwelling shortwave radiation | W m-2 | 1979-01-01 07:00:00 to 2018-12-31 23:00:00 | 1979-01-01 07:00:00 to 2019-12-31 23:00:00 |
Rainf (CRU) | Rainfall flux (corrected using CRU TS dataset) | kg m-2 s-1 | 1979-01-01 07:00:00 to 2018-12-31 23:00:00 | 1979-01-01 07:00:00 to 2019-12-31 23:00:00 |
Snowf (CRU) | Snowfall flux (corrected using CRU TS dataset) | kg m-2 s-1 | 1979-01-01 07:00:00 to 2018-12-31 23:00:00 | 1979-01-01 07:00:00 to 2019-12-31 23:00:00 |
Rainf (CRU+GPCC) | Rainfall flux (corrected using CRU TS and GPCC datasets) | kg m-2 s-1 | 1979-01-01 07:00:00 to 2016-12-31 23:00:00 | 1979-01-01 07:00:00 to 2019-12-31 23:00:00 |
Snowf (CRU+GPCC) | Snowfall flux (corrected using CRU TS and GPCC datasets) | kg m-2 s-1 | 1979-01-01 07:00:00 to 2016-12-31 23:00:00 | 1979-01-01 07:00:00 to 2019-12-31 23:00:00 |
ASurf | Gird-point altitude | m | - | - |
Table 2: WFDE5 versions historyAnchor table2 table2
Version | Observational datasets used | Changes from previous version |
v1.0 | · CRU TS 4.03 (all variables) · GPCCv2018 (Rainf and Snowf) | - |
v1.1 | · CRU TS 4.03 (all variables) · GPCCv2018 (Rainf and Snowf) | · Fix SWdown values, affected in v1.0 by a bug compromising correct computation |
v2.0 | · CRU TS 4.04 (all variables) · GPCCv2020 (Rainf and Snowf) | · Use latest versions of the observational datasets · Extend time coverage to 2019 · Update diurnal temperature range correction algorithm |
| v2.1 | · CRU TS 4.04 (all variables) · GPCCv2020 (Rainf and Snowf) | · Fix issue affecting Qair and LWdown values (see "Known issues" section) |
Table 3: Input datasetsAnchor table3 table3
Dataset | Summary | Variables used |
ERA5 | ECMWF reanalysis product | · 10 m u-component of wind · 10 m v-component of wind · 2 m temperature · Surface pressure · 2 m dewpoint temperature · Surface thermal radiation downwards · Surface solar radiation downwards · Cloud cover · Total precipitation · Snowfall · Land-sea mask · Lake cover mask · Orography |
CRU TS 4.03, CRU TS 4.04 | Climate Research Unit gridded station observations (multiple variables) | · Temperature · Diurnal temperature range · Cloud cover · Wet days · Precipitation · Grid-points altitude |
GPCCv2018, GPCCv2020 | Global Precipitation Climatology Centre gridded station precipitation observations | · Precipitation |
Other | - | · Rainfall and snowfall gauge corrections 1 · Aerosol loading corrections to shortwave downward radiation 2 |
| Info | ||
|---|---|---|
| ||
1Provided by Jennifer Adam (jcadam@wsu.edu), following the methodology described in [8] 2Provided by Nicolas Bellouin (n.bellouin@reading.ac.uk), following the methodology described in [1] with updates on input datasets described in [7]. |
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Table 4: WFDE5 dataset general attributesAnchor table4 table4
Dataset attribute | Details |
Horizontal coverage | Global |
Horizontal resolution | 0.5° x 0.5° |
Vertical coverage | Surface |
Temporal coverage | Depends on variable (see Table 3) |
Temporal resolution | Hourly |
File format | netCDF |
Data type | Grid |
Versions | v1.0, v1.1, v2.0, v2.1 |
Aggregation to the half-degree grid is applied on sea-level adjusted values of the different ERA5 variables, which are obtained as part of the elevation-correction procedure.
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If publishing using this dataset please cite [7], where a more detailed description of the dataset can be found.
Anchor appendixa appendixa
Appendix A – WFDE5v2.0: DTR-based correction algorithm update
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- For each month, interpolated ERA5 hourly near-surface air temperatures are used to compute the ERA5 interpolated monthly average diurnal temperature range (DTRE5,mm);
DTR correction factors A and R are computed in the following way:
Mathdisplay A = DTR_{CRU} - DTR_{E5,mm}Mathdisplay R = \frac{DTR_{CRU}}{DRT_{E5,mm}}ERA5 interpolated diurnal temperature range values are corrected (DTRE5,corr), depending on the value of R at each grid-point, in the following way:
Mathdisplay DTR_{E5,corr} = \begin{cases} DTR_{E5} * R & R \le 1 \\ DTR_{E5} + A & R < 1 \\ \end{cases}A multiplicative correction factor F is computed as:
Mathdisplay F = \frac{DTR_{E5,corr}}{DTR_{E5}}After applying the correction for monthly mean biases, deviations of corrected hourly ERA5 near-surface air temperature values (TairE5,corr) from their respective daily means (TairE5,corr,dm) are multiplied by F , and results are added to ERA5 near-surface air temperature daily means (TairE5,dm) to obtain final corrected hourly WFDE5 near-surface air temperature values (TairW5):
Mathdisplay Tair_{W5} = Tair_{E5,corr,dm} + (Tair_{E5,corr} - Tair_{E5,corr,dm}) \ast F
Anchor appendixb appendixb
Appendix B – WFDE5v2.1: Qair derivation algorithm update
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