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 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 Atmospheric Dynamics group at IAC, ETH Zürich, Switzerland; the LSDP group at Karlsruhe Institute of Technology, Germany; and the 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:

ERA5 data files in ETH Zurich format format

File name	Pyyyymmdd_hh		Zyyyymmdd_hh	Hyyyymmdd_hh	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	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 ECMWF ERA5 data documentation for parameter abbreviations.

Conditions of use: When using the ERA5 data from this archive please make sure to reference "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

ERA5 data files in Bergen format

Folder	Data available (see [1] for parameter abbreviations)	Details
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 Papritz and Spengler, 2015, for more details):

Variable name	Description	Equation	Units	Notes
slope	Slope of isentropic surface	S = abs(gradθz)	m m-1	Instantaneous
tilt	Tendency in slope due to tilting	gradθz /S · gradθ wid	m m-1 s-1	Instantaneous
diab	Tendency in slope due to diabatic heating	-dz/dθ gradθz /S · gradθ (dθ/dt)	m m-1 s-1	Accumulated over 6-hour period centred on instantaneous time step (stored as instantaneous, ans)
iadv	Tendency in slope due to isentropic advection	u · gradθS	m m-1 s-1	Instantaneous
w_ci	Cross isentropic vertical velocity	w - wiu	m s-1	Instantaneous
mask_slope	Combination of masks from slope, diab and tilt	-	0-1	Instantaneous