View source for ERA5 reanalysis data

GFI is building up an archive of ERA5 reanalysis data on the local linux system cyclone.hpc.uib.no. ERA5 supersedes the ERA-Interim reanalysis data, which ended in August 2019. More information about the ERA5 reanalysis data set is available [https://www.ecmwf.int/en/forecasts/datasets/reanalysis-datasets/era5 at ECMWF's ERA5 websites].

The ERA5 data files are available in two different CF-compatible netCDF formats (ETH Zurich format and Bergen format) at
 
 /Data/gfi/share/era5


== Data in ETH Zurich format ==

Data in the ETH Zurich format is collected in one subfolder:

 ml/        3-hourly data on a regular 0.5 deg lat-lon grid, with model-level and pressure level files (see below)


Data in the '''ml'''-folder are contained in subdirectories for each year and month:

 ml/yyyy/mm/[B|H|P|Z]yyyymmdd_hh

where yyyy is the year, mm the two-digit month, dd the two-digit day, and hh the two-digit hours, and Bxxx, Hxxx, Pxxx, Zxxx are different file types, as described in the table below. This format is the same used at the [https://iac.ethz.ch/group/atmospheric-dynamics.html Atmospheric Dynamics group at IAC, ETH Zürich, Switzerland]; the [https://www.imk-tro.kit.edu/7425.php LSDP group at Karlsruhe Institute of Technology, Germany]; and the [https://www.weizmann.ac.il/EPS/raveh-rubin/ Dynamical Meteorology Group, Weizmann Institute of Science, Rehovot, Israel].

Until now, the years 1999-2018 have been retrieved. The period will successively be extended back to 1979, and forward in time.

The data files contain the following variables:

{| class="wikitable"
|+ '''ERA5 data files in ETH Zurich format format'''
|-
|File name
|colspan="2"|Pyyyymmdd_hh
|colspan="1"|Zyyyymmdd_hh
|colspan="1"|Hyyyymmdd_hh
|colspan="1"|Byyyymmdd_hh
|-
|Leveltype
|Model level
|Surface
|Pressure
|Pressure
|Surface
|-
|Variables
|T, Q, U, V, OMEGA, LWC, IWC, RWC, SWC
|LSP, CP, SF, SSHF, SLHF, BLH, TCC, U10M, V10M, MSL, PS, SSTK
|Z, T, Q, U, V
|Z
|PS, MSL, TCC, U10M, V10M, SSTK, CI, D2M, T2M, TCW, TCWV, VIWVD, E, MN2T, MX2T, SI, TTR, TTRC, WG10, LSP, CP, SF, SSHF, SLHF, BLH
|-
|Levels
|40-137
| -
|900, 850, 800, 700, 600, 500, 400, 300, 250, 200, 100 hPa
|1000, 975, 950, 925, 900, 875, 850, 825, 800, 775, 750, 700, 650, 600, 550, 500, 450, 400, 350, 300, 250, 225, 200, 175, 150, 125, 100, 70, 50, 30, 20, 10, 70, 5, 3, 2, 1 hPa
| -
|-
|Times available
|colspan="5"|00, 03, 06, 09, 12, 15, 18, 21 UTC
|}

Note that the variables LSP, CP, SF, SSHF, SLHF, and BLH are derived as prognostic variables from the short-range forecast. Data valid at 00, 03, 06, 09 UTC are 06, 09, 12, 15 h forecast of the 18 UTC forecast of the previous day. Accordingly, data valid at 12, 15, 18, 21 UTC are 06, 09, 12, 15 h forecast of the 06 UTC forecast. The prognostic variables are accumulated over the previous 1 h.

Please see [https://confluence.ecmwf.int/display/CKB/ERA5%3A+data+documentation ECMWF ERA5 data documentation] for parameter abbreviations.

'''Conditions of use:''' When using the ERA5 data from this archive please make sure to reference "[https://cds.climate.copernicus.eu/cdsapp#!/home Copernicus Climate Change Service (C3S) (2017): ERA5: Fifth generation of ECMWF atmospheric reanalyses of the global climate. Copernicus Climate Change Service Climate Data Store (CDS)], date of citation" and acknowledge "ECMWF for providing ERA-5 data“. Also, please acknowledge "Michael Sprenger (ETH Zurich)“ for the support in providing the data.


== Data in Bergen format ==

Data in the Bergen format is in the following subfolders:

 pl/                  Pressure level data.
 pl_tendencies/       Diabatic temperature tendencies on pressure levels.
 pv2/                 Data on the PV2-surface.
 sfc/                 Single-level data.
 detected_features/   Weather events identified by various detection algorithms.
 slope/               Isentropic slope data and its tendencies.

Data in these folders is organised in one file per month, variable and level, for example:

 pl/ea.[ans|for].yyyymm.plev.var

This data is completely available for 1979-2022. Specifically, we have the following data available

{| class="wikitable"
|+ '''ERA5 data files in Bergen format'''
|-
!colspan="1"|Folder
!colspan="1"|Data available (see [https://confluence.ecmwf.int/display/CKB/ERA5%3A+data+documentation] for parameter abbreviations)
!colspan="1"|Details
|-
| rowspan=2 | '''sfc/'''
|blh, msl, siconc, sp, sst, t2m, tcwv, u10, v10, viewvf, vinwf
|Instantaneous (ans)
|-
|cp, lsp, slhf, sshf, ssrd, ssr, strd, str, tsr, ttr
|Accumulated over previous 3 hours (for)
|-
|'''pl/'''
|t, q, z, u, v, w
|Instantaneous (ans)
|-
|'''pl_tendencies/'''
|mttlwrcs, mttlwr, mttpm, mttswrcs, mttswr
|Accumulated over previous 3 hours (for)
|-
|'''pv2/'''
|u, v, pt, pres
|Instantaneous (ans)
|}

The folder '''detected_features/''' contains detected cyclones, anticyclones, fronts, jet axes, moisture transport axes, cold-air outbreaks, frontal volumes, Rossby wave breaking, and blocking events. For details on the different weather features refer to the '''README''' in the folder.

The folder '''slope/''' contains data deriving from the isentropic slope framework (see  [https://doi.org/10.1002/qj.2605 Papritz and Spengler, 2015], for more details):

{| class="wikitable"
!colspan="1"|Variable name
!colspan="1"|Description
!colspan="1"|Equation
!colspan="1"|Units
!colspan="1"|Notes
|-
|slope
|Slope of isentropic surface
| S = abs(grad<sub>θ</sub>z)
|m m<sup>-1</sup>
|Instantaneous
|-
|tilt
|Tendency in slope due to tilting
| grad<sub>θ</sub>z /S · grad<sub>θ</sub> w<sub>id</sub>
|m m<sup>-1</sup> s<sup>-1</sup>
|Instantaneous
|-
|diab
|Tendency in slope due to diabatic heating
| -dz/dθ grad<sub>θ</sub>z /S · grad<sub>θ</sub> (dθ/dt)
|m m<sup>-1</sup> s<sup>-1</sup>
|Accumulated over 6-hour period centred on instantaneous time step (stored as instantaneous, ans)
|-
|iadv
|Tendency in slope due to isentropic advection
| '''u''' · grad<sub>θ</sub>S
|m m<sup>-1</sup> s<sup>-1</sup>
|Instantaneous
|-
|w_ci
|Cross isentropic vertical velocity
| w - w<sub>iu<sub>
|m s<sup>-1</sup>
|Instantaneous
|-
|mask_slope
|Combination of masks from slope, diab and tilt
| -
|0-1
|Instantaneous
|}