ERA5 reanalysis · 500 hPa wind
Every strand is a parcel of air at 500 hPa, walked forward through the
analysed wind field and tinted by the heat anomaly beneath it —
· .
·
Land in view, mean anomaly
· °C
middle 80% of land cells spans ·
Anomaly over the window drag
Land-cell mean, °C; band is the 10th–90th percentile. Drag to move the clock.
Where the land sits now ·
·
Share of the · land cells in view, by 1 °C bin.
Open for more
How to read this map the four channels ▾
Direction
Each strand is combed downwind : it grows from its own root
toward where the air at 500 hPa is heading, so the tip is the
destination, not the source. (The wind rose below counts the opposite
convention — the direction the wind comes from — because that
is how a rose is read.)
Length
Increases with wind speed, at · . It is
clipped at both ends, so a strand stops growing at about
· . Beyond that limit, use the wind readings
in km/h or m/s; the decorative gust speed is not a calibrated
measurement.
Colour
The 2 m temperature anomaly under the strand's root , on the
roma ramp shown in the legend, spanning
· . The ends are caps, marked “≤” and “≥”:
anything beyond them takes the end colour. Zero anomaly is the pale
sand in the middle of the ramp — it is a value, not an absence.
Movement
Playing the clock morphs every strand from its shape at one analysis
hour to its shape at the next. The motion you see is
interpolation between 3-hourly analyses , not a simulation of
turbulence, and nothing in it resolves anything faster than three
hours.
City dots: absolute 2 m temperature (°C). Dot colour is temperature, not anomaly. The two callout readings are anomaly, then absolute temperature. End colours are capped.
Where there is no data. The anomaly is defined over land only.
Sea cells carry no value and are left as the flat slate ground with no
fur on them at all — visibly absent , never a colour from the
ramp. The land-cell counts, the histogram and the hero figure are all
taken over the · land cells inside the
current frame, and no further.
What is drawing, not data. Four things on this map are there to
make air legible and carry no information: the fixed curl in every
strand (the same in each, which is what turns bent lines into fur); the
gust ripple, a smooth noise field drifting downwind that appears
only while the clock is playing ; the parting and clumping of
the coat, which is a fixed spatial pattern rather than a measured
convergence; and a small lift in saturation and a soft glow on the
brightest strands. The legend bar is drawn from the untouched ramp, so
it always shows the true colour of a value. Strand roots sit on a
jittered lattice — they are not stations, and no single strand is an
observation.
Flow wind rose · 500 hPa ▾
Sixteen sectors by the direction the wind comes from , weighted by
speed across the whole domain; the ring marks an even split. Fastest cell
now: · .
The cities table · by anomaly ▾
Bilinear samples at each city, ranked by the window's mean anomaly — rows
hold their places so a city can be followed. Anomaly °C against the
baseline; 2 m is the absolute temperature; wind is the 500 hPa flow above
the city, arrow pointing where it blows to. Focus or tap a row to find
it on the map.
Method & sources how it was made ▾
· UTC
The wind field is the ERA5 reanalysis at 500 hPa on its native 0.25°
grid ; the temperature is ERA5 2 m temperature on the same grid. The
anomaly is the difference between each cell's 2 m temperature and a
climatology built for that calendar month and that hour of day
across the baseline years, which is why a 03:00Z reading and a 15:00Z
reading are directly comparable. Strand roots are laid on a jittered
lattice over the land mask, walked forward through the analysed wind,
and drawn once per step; between steps their shapes are interpolated.
No forecast is involved and nothing is extrapolated past the window.
Phone edition. To cut the download from about 13 MB to about
4 MB, this edition carries the same fields averaged over 2 × 2 cells
(0.5°). The flow is slightly smoother, and single-cell extremes (the ×
marks) can read up to about 1 °C milder than in the full edition.
Open the full-resolution edition (about 13 MB) .
·
·
ERA5 contains modified Copernicus Climate Change Service information;
neither the European Commission nor ECMWF is responsible for any use of
it. Boundaries © EuroGeographics for the administrative boundaries.
·
Map of Europe and the north-east Atlantic.
Every one of about thirty thousand strands is a parcel of air at the 500
hectopascal level: it starts at its own point on the map and is combed
along the analysed wind, so the strand points the way the wind blows to,
and it is longer where the wind is faster. Each strand is tinted by the
2 metre temperature anomaly under its root — deep red where the surface
is much warmer than the baseline, sand where it is near it, and
blue-green where it is cooler. The sea is left as flat slate.
← → step · space play
Europe,combed by the wind
· °C Land in view, mean anomaly
▴
◂
▸
▾
×
Pinned probe
·
Anomaly °C ·
Wind km/h ·
× marks the hottest and coldest land cell, and the fastest wind. These are
single cells rather than averages, so they are held at the whole hour each label names, while
every other reading on the page follows the clock continuously.
