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-   -   ECMWF wind speed ? (https://www.weather-banter.co.uk/uk-sci-weather-uk-weather/202228-ecmwf-wind-speed.html)

N_Cook January 16th 21 10:08 AM

ECMWF wind speed ?
 
All very pretty , such images as 10m wind speed on
https://www.ecmwf.int/en/forecasts/charts/catalogue
but next to useless without reference to the constant of proportionality
of pixel length to knots/kph/mph/mps or whatever of the wind arrows. Why
no conventional wind barbs , if they have to confuse it all with
temperature ?
Try googling gets nowhere as to an ECMWF explainer. Anyone been here
before and knows the constant of proportionality or do I have to compare
to GFS isotachs for say 19 Jan, the next locally high wind regime.? Is
it even a linear scale?

--
Global sea level rise to 2100 from curve-fitted existing altimetry data
http://diverse.4mg.com/slr.htm

N_Cook January 16th 21 01:25 PM

ECMWF wind speed ?
 
On 16/01/2021 10:08, N_Cook wrote:
All very pretty , such images as 10m wind speed on
https://www.ecmwf.int/en/forecasts/charts/catalogue
but next to useless without reference to the constant of proportionality
of pixel length to knots/kph/mph/mps or whatever of the wind arrows. Why
no conventional wind barbs , if they have to confuse it all with
temperature ?
Try googling gets nowhere as to an ECMWF explainer. Anyone been here
before and knows the constant of proportionality or do I have to compare
to GFS isotachs for say 19 Jan, the next locally high wind regime.? Is
it even a linear scale?


First interim datapoint ,as assuming GFS= ECMWF 3 days out, for 10m
average wind in the Biscay area of the N Atlantic plot.
60kph wind arrow = 33 pixels
So it could be a linear scale, as hurricane force wind would be
plottable on that scale.
Don't you just love super-computers.

--
Global sea level rise to 2100 from curve-fitted existing altimetry data
http://diverse.4mg.com/slr.htm

N_Cook January 20th 21 02:48 PM

ECMWF wind speed ?
 
I've decided the ECMWF 10m wind plots are a waste of space. GFS has
projected, rightly or wrongly, easy to determine sustained 70mph wind
over the Channel Approaches 29 Jan.
The corresponding ECMWF max winds has absurdely long arrows protruding
well into France, so presumably the blunt barbless end of the arrow is
the relevant datapoint ,but next to uselss, for severe gale purposes.

--
Global sea level rise to 2100 from curve-fitted existing altimetry data
http://diverse.4mg.com/slr.htm

N_Cook January 31st 21 09:39 AM

ECMWF wind speed ?
 
On 20/01/2021 14:48, N_Cook wrote:
I've decided the ECMWF 10m wind plots are a waste of space. GFS has
projected, rightly or wrongly, easy to determine sustained 70mph wind
over the Channel Approaches 29 Jan.
The corresponding ECMWF max winds has absurdely long arrows protruding
well into France, so presumably the blunt barbless end of the arrow is
the relevant datapoint ,but next to uselss, for severe gale purposes.


The fletchless, not barbless, ends of the so-called wind arrows are on a
regular grid, so presumably are the points of interest.
For the NW Europe 10m wind plots, very approximately, 55 pixels of
"wind arrow" represent 60 kph wind speed

--
Global sea level rise to 2100 from curve-fitted existing altimetry data
http://diverse.4mg.com/slr.htm

N_Cook February 16th 21 08:30 AM

ECMWF wind speed ?
 
On 31/01/2021 09:39, N_Cook wrote:
On 20/01/2021 14:48, N_Cook wrote:
I've decided the ECMWF 10m wind plots are a waste of space. GFS has
projected, rightly or wrongly, easy to determine sustained 70mph wind
over the Channel Approaches 29 Jan.
The corresponding ECMWF max winds has absurdely long arrows protruding
well into France, so presumably the blunt barbless end of the arrow is
the relevant datapoint ,but next to uselss, for severe gale purposes.


The fletchless, not barbless, ends of the so-called wind arrows are on a
regular grid, so presumably are the points of interest.
For the NW Europe 10m wind plots, very approximately, 55 pixels of
"wind arrow" represent 60 kph wind speed


A bit mpre sensibly , comparing cut-down MetO Euro4 and the NW Europe
ECMWF 10m wind plot for 2 lat&long samplings, of 73 and 83 kph
sustained, NW of Ireland last night, comes out to be 60kph equates to
about 29 pixels

--
Global sea level rise to 2100 from curve-fitted existing altimetry data
http://diverse.4mg.com/slr.htm


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