# Wind Calculation

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nickh07@...
Wind Calculation

Hi,

What variables would I need to create mean global wind fields? I guess it would include the manipulation of V and U though I'm not sure.

Nick

rneale

You can create global mean wind fields from the U and V output fields along with
gaussian weight field (gw) which will allow you to weight the values of U and V with decreasing area as the grid size decreases towards the pole.

Richard Neale CESM AMWG Co-chair eval(unescape('%64%6f%63%75%6d%65%6e%74%2e%77%72%69%74%65%28%27%3c%61%20%68%72%65%66%3d%22%6d%61%69%6c%74%6f%3a%72%6e%65%61%6c%65%40%75%63%61%72%2e%65%64%75%22%20%63%6c%61%73%73%3d%22%62%62%2d%65%6d%61%69%6c%22%3e%72%6e%65%61%6c%65%40%75%63%61%72%2e%65%64%75%3c%2f%61%3e%27%29%3b')) http://www.cgd.ucar.edu/cms/rneale Atmosphere Modeling and Predictability Section, AMP, NCAR Tel (303) 497-1380 Fax (303) 497-1324

nickh07@...

thanks richard for the reply, so would I just add U and V together for a mean wind direction. Also, is level 15 of CAM the standard for getting a "mean" wind field?

cheers,

Nick

rneale

At each vertical level you can use U and V to calculate the mean magnitude. I am not sure calculating the mean wind direction will tell you anything?

There is no standard level based on level number (15 as you say), but there are some standard pressure levels. It all depends on what you are interesting in.

Richard Neale CESM AMWG Co-chair eval(unescape('%64%6f%63%75%6d%65%6e%74%2e%77%72%69%74%65%28%27%3c%61%20%68%72%65%66%3d%22%6d%61%69%6c%74%6f%3a%72%6e%65%61%6c%65%40%75%63%61%72%2e%65%64%75%22%20%63%6c%61%73%73%3d%22%62%62%2d%65%6d%61%69%6c%22%3e%72%6e%65%61%6c%65%40%75%63%61%72%2e%65%64%75%3c%2f%61%3e%27%29%3b')) http://www.cgd.ucar.edu/cms/rneale Atmosphere Modeling and Predictability Section, AMP, NCAR Tel (303) 497-1380 Fax (303) 497-1324

nickh07@...

thanks richard,

im using wind direction anomalies to see any effects of altimetry.

And just to confirm, out of the 26 levels, 1 is at ground elevation and 26 at the top of the atmoshpere?

cheers,

Nick

rneale

The levels go from 1 at the top of the model, to 26 next to the surface

Richard Neale CESM AMWG Co-chair eval(unescape('%64%6f%63%75%6d%65%6e%74%2e%77%72%69%74%65%28%27%3c%61%20%68%72%65%66%3d%22%6d%61%69%6c%74%6f%3a%72%6e%65%61%6c%65%40%75%63%61%72%2e%65%64%75%22%20%63%6c%61%73%73%3d%22%62%62%2d%65%6d%61%69%6c%22%3e%72%6e%65%61%6c%65%40%75%63%61%72%2e%65%64%75%3c%2f%61%3e%27%29%3b')) http://www.cgd.ucar.edu/cms/rneale Atmosphere Modeling and Predictability Section, AMP, NCAR Tel (303) 497-1380 Fax (303) 497-1324

scapps@...

So, to plot the near surface wind magnitudes, I have added the following code in the srfxfer.F90 module:

sqrt(state%u(i,pver)**2 + state%v(i,pver)**2))

where "i" is the column index, "state" is the physics_state derived type and "pver" is the lowest mid-layer level.

This gives me surface wind magnitudes at about 992.5 mb.

Scott

rneale

That looks correct to me

Richard Neale CESM AMWG Co-chair eval(unescape('%64%6f%63%75%6d%65%6e%74%2e%77%72%69%74%65%28%27%3c%61%20%68%72%65%66%3d%22%6d%61%69%6c%74%6f%3a%72%6e%65%61%6c%65%40%75%63%61%72%2e%65%64%75%22%20%63%6c%61%73%73%3d%22%62%62%2d%65%6d%61%69%6c%22%3e%72%6e%65%61%6c%65%40%75%63%61%72%2e%65%64%75%3c%2f%61%3e%27%29%3b')) http://www.cgd.ucar.edu/cms/rneale Atmosphere Modeling and Predictability Section, AMP, NCAR Tel (303) 497-1380 Fax (303) 497-1324

shine_sea2004@...

Hmm... I think 992.5561 Hpa is about 61m, which is not near the surface. Am I right? -Joyce

rangel@...

Hi,

I have a question about how to proper apply the gw to calculate the wind field at any level.

If I only multiply the field by gw, the results are very small wind values.

Say I'm trying to calculate the V component, which is V(lon,lat,levels,time) = V(144,96,32,1000).

If I choose one V value, as an example, that is in the lat index number 49 (V=10m/s). The gw in that lat is 0.0331.

So, after the multiplication, the new V wind is 0.331 m/s. That is an very low value.

What am I doing wrong?

Any help will be very appreciated!