windspeed from u & v

[frapas70]

Is your feature request related to a problem? Please describe.

Hi is it possible to calculate windspeed from u&v?

Describe the solution you'd like

No response

Describe alternatives you've considered

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[sandorkertesz]

@frapas70, there is a the speed() method available in earthkit-meteo but currently it only works for arrays (e.g. numpy) and not for high-level objects like fieldlists:

https://earthkit-meteo.readthedocs.io/en/latest/_api/meteo/wind/array/speed.html#meteo.wind.array.speed

What is your input data you want to compute the wind speed for?

[frapas70]

Grib2: I am trying with IFS opendata, but I would like to use also with our models (i hope no differences..)
data = earthkit.data.from_source("file", "ifs.00z.grb2")
var1=data.sel(shortName="u",level=500,stepRange="12")
var2=data.sel(shortName="v",level=500,stepRange="12")

[sandorkertesz]

Only low level, array-based, computations are available for this data. This notebook example shows you how it works:

https://earthkit-data.readthedocs.io/en/latest/examples/numpy_fieldlist.html

You can use it to compute the windspeed from var1 and var2 and write result back to GRIB.

[frapas70]

Thanks this an interesting feature very useful for many applications. I can get around with this. I am a little bit worried about the time it takes to make these read/write steps, because in comparison with the the software I am using (Grads), earthkit is already slower. I need to make may maps so speed is my main issue.
Do you have examples of how to get cumulated precipitation (eg. 3h, 6h, so on) from hourly pcp and viceversa? And how to calculated dailymax/min (for temperature)