ERA5 weather variables have incorrect units and names

[mrmorawski]

Version Checks (indicate both or one)

• I have confirmed this bug exists on the lastest release of atlite.

• I have confirmed this bug exists on the current master branch of atlite.

Issue Description

Units and names for multiple variables in era5 are incorrect.

Here are the units and long_names extracted from an example cutout:

Variable	Reported units	Correct units	Reported long_name	Correct long_name
height	m**2 s**-2	m	Geopotential	Height
wnd100m	m s**-1	m s**-1	100 metre wind speed	—
wnd_shear_exp	`` (empty)	`` (empty)	wind shear exponent	—
wnd_azimuth	m s**-1	rad	100 metre U wind component	100 metre wind azimuth
roughness	m	m	Forecast surface roughness	—
influx_toa	W m**-2	W m**-2	TOA incident short-wave ...	—
influx_direct	W m**-2	W m**-2	Surface direct short-wave ...	—
influx_diffuse	W m**-2	W m**-2	Surface diffuse solar ...	—
albedo	(0 - 1)	(0 - 1)	Albedo	—
solar_altitude	rad	rad	latitude	solar altitude
solar_azimuth	rad	rad	latitude	solar azimuth
temperature	K	K	2 metre temperature	—
soil temperature	K	K	Soil temperature level 4	—
dewpoint temperature	K	K	2 metre dewpoint temperature	—
runoff	m	m	Runoff	—

I see 4 issues:

1. height is still listed in geopotential units m**2 s**-2, even though it is converted to m.
2. wnd_azimuth is in velocity units m s**-1 even though it's an angle and should be in rad
3. solar_altitude and solar_azimuth inherit the latitude long name from the locational variables that are used to calculate them
4. Capitalisation of long_name's is inconsistent, some start with a capital and some don't.

Reproducible Example

import atlite

# should download pretty fast, same as conftest
cutout = atlite.Cutout(
    path="mre_era5.nc",
    module="era5",
    bounds=(-4, 56, 1.5, 62),
    time="2013-01-01",
)
cutout.prepare()

print(f"{'variable':22s} {'units':12s} long_name")
print("-" * 70)
for v in cutout.data.data_vars:
    attrs = cutout.data[v].attrs
    print(f"{v:22s} {str(attrs.get('units', '')):12s} {attrs.get('long_name', '')}")

Expected Behavior

units are physically correct

Installed Versions

Details

argcomplete==3.1.4
attrs==23.2.0
Babel==2.10.3
bcc==0.29.1
bcrypt==3.2.2
beautifulsoup4==4.12.3
blinker==1.7.0
Brlapi==0.8.5
Brotli==1.1.0
certifi==2023.11.17
chardet==5.2.0
click==8.1.6
cloud-init==25.3
colorama==0.4.6
command-not-found==0.3
configobj==5.0.8
cryptography==41.0.7
cssselect==1.2.0
cupshelpers==1.0
dbus-python==1.3.2
defer==1.0.6
defusedxml==0.7.1
distro==1.9.0
distro-info==1.7+build1
duplicity==2.1.4
fasteners==0.18
html5lib==1.1
httplib2==0.20.4
idna==3.6
Jinja2==3.1.2
jsonpatch==1.32
jsonpointer==2.0
jsonschema==4.10.3
language-selector==0.1
launchpadlib==1.11.0
lazr.restfulclient==0.14.6
lazr.uri==1.0.6
libevdev==0.5
louis==3.29.0
lxml==5.2.1
Mako==1.3.2.dev0
Markdown==3.5.2
markdown-it-py==3.0.0
MarkupSafe==2.1.5
mdurl==0.1.2
meson==1.3.2
monotonic==1.6
netaddr==0.8.0
netifaces==0.11.0
numpy==1.26.4
oauthlib==3.2.2
olefile==0.46
openshot-qt==3.5.1
packaging==24.0
paramiko==2.12.0
pexpect==4.9.0
pillow==10.2.0
pipx==1.4.3
platformdirs==4.2.0
psutil==5.9.8
ptyprocess==0.7.0
py==1.11.0
pycairo==1.25.1
pycups==2.0.1
Pygments==2.17.2
PyGObject==3.48.2
PyJWT==2.7.0
PyNaCl==1.5.0
pyparsing==3.1.1
PyQt5==5.15.10
PyQt5-sip==12.13.0
PyQtWebEngine==5.15.6
pyrsistent==0.20.0
pyserial==3.5
python-apt==2.7.7+ubuntu5.2
python-dateutil==2.8.2
python-debian==0.1.49+ubuntu2
pytz==2024.1
pyudev==0.24.0
pyxdg==0.28
PyYAML==6.0.1
pyzmq==24.0.1
requests==2.31.0
rich==13.7.1
rofication==1.2.2
scour==0.38.2
sentry-sdk==1.39.2
setuptools==68.1.2
six==1.16.0
soupsieve==2.5
systemd-python==235
typing_extensions==4.10.0
ubuntu-drivers-common==0.0.0
ubuntu-pro-client==8001
ufw==0.36.2
unattended-upgrades==0.1
urllib3==2.0.7
usb-creator==0.3.16
userpath==1.9.1
wadllib==1.3.6
webencodings==0.5.1
wheel==0.42.0
xdg==5
xkit==0.0.0

[mrmorawski]

I don't think this impacts the downstream capacity calculations. The fix would be to assign_attrs in era5.py. That would be a breaking change, but I doubt anyone is relying on the incorrect units downstream?

[fneum]

Happy to introduce this breaking change. I think no-one (developer or user) paid attention to the meta data so far...