Author Topic: 10m Wind Altitude  (Read 1761 times)

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Offline wxnerd

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10m Wind Altitude
« on: July 06, 2023, 08:16:04 PM »
As a meteorologist that's used to dealing with questions from the public, I actually had one that stumped me a bit. This was kind of a long discussion with a guy that was not a meteorologist, but seemed to have an above-average knowledge of physics and common sense. He asked me why we take official wind measurements at 10 meters and not the same 2 meter (near average human height) that we do temperature.

At first, I explained the obvious reasonings of ground friction slowing winds, trees/buildings/other structures slowing/blocking/altering winds and the need to have uninterrupted low level flow information to track temp/moisture advection.

His response: That makes sense and I can see why a forecaster would want to know 10m wind as well as winds at all levels of the atmosphere, but a 2m wind would be more important to your average Joe because that's the wind he actually feels blowing on his face. Even if it's a slower speed due to friction, that's just part of natural physics and it's what he's actually feeling. Plus, you use this to calculate wind chill. Well, unless he's sitting on the top of a 30 foot tree, that can't be what the temperature feels like on his skin because he's not experiencing the full amount of that wind speed at ground level. Shouldn't we also have wind gauges reporting from 2m to give a better idea of the human experience?

I was a bit stumped and didn't know what to say. Because the more I thought about it, he actually kind of had a valid point. Especially with wind chill. How can we honestly say "this is what the temp feels like to the human skin" when the human skin is only experiencing a fraction of the wind speed we're using the calculate with? I got to thinking that maybe there would be some value if stations in unsheltered spots had 2 anemometers reporting both 2m and 10m winds? I realize, it's impossible to replicate all the possibilities of blocking from trees/building, but a 2m in open field measurement would at least incorporate the frictional drag and give a closer estimate of "max possible" winds that human would experience.

Curious as to what others in the weather industry think. Could 2m wind have some "personal" value even if it's of little scientific value? Is this another chapter of "Serving science over the people" (ie. the whole "Superstorm Sandy" debacle of changing the status from tropical to extratropical before landfall for scientific reasons without thought of how it could impact the public. Many mistakenly thought the storm had somehow weakened rather than simply a change in temperature structure within the storm.) Maybe we are concentrating on 10m winds for our own scientific reasons and underestimating the value that a true surface wind could have for the general public?

Would love to hear your thoughts!
« Last Edit: July 06, 2023, 08:27:16 PM by wxnerd »

Offline CW2274

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Re: 10m Wind Altitude
« Reply #1 on: July 06, 2023, 08:32:08 PM »
I don't know this as fact, but makes complete sense to me. Wind measurement is one of, if not the most important aspects of landing a plane. Given that a median-ish height for air-carrier aircraft control surfaces is about 10 meters AGL, that's why it's measured there.

Offline wxnerd

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Re: 10m Wind Altitude
« Reply #2 on: July 06, 2023, 09:11:06 PM »
I don't know this as fact, but makes complete sense to me. Wind measurement is one of, if not the most important aspects of landing a plane. Given that a median-ish height for air-carrier aircraft control surfaces is about 10 meters AGL, that's why it's measured there.

Does make sense. I'm certainly not in favor of doing away with 10m wind measurements. I just wonder if there's some value of adding a 2m wind in addition.

Honestly, I'd love to have a 2,000ft towers and just litter them with sensors every couple feet from the ground up. Live, high resolution temp and wind data of the whole lower atmosphere! If only there was an unlimited budget! But I digress....

Offline mcrossley

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Re: 10m Wind Altitude
« Reply #3 on: July 07, 2023, 04:15:01 AM »
My in-expert thoughts...

The 2m wind is usually much more turbulent and gusty in typical environments. I expect depending on topology (buildings etc) the guests may sometimes exceed the 10m value though the average is lower.

There's not that many people experience a laminar open field airflow to make the 2m reading that meaningful either, though it may be closer to the truth.
Mark

Offline weatherdoc

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Re: 10m Wind Altitude
« Reply #4 on: July 07, 2023, 07:03:32 AM »
According to the World Meteorological Organization (https://library.wmo.int/doc_num.php?explnum_id=3177#:~:text=Wind%20observations%20or%20measurements%20are%20required%20for%20weather,evaporation%20for%20air%20pollution%20dispersion%20and%20agricultural%20applications.)

Section 5.9 EXPOSURE OF WIND INSTRUMENTS
5.9.1 General problems
Wind speed increases considerably with height, particularly over rough terrain. For this reason, a standard height of 10 m above open terrain is specified for the exposure of wind instruments.

Offline TheBushPilot

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Re: 10m Wind Altitude
« Reply #5 on: July 07, 2023, 05:27:18 PM »
IIRC WMO actually changed the height of wind measurement way back when to accommodate for the larger size of modern aircraft.

I know wind at 2 meters is not standard for general application meteorological stations but quite a few of the state and university funded mesonet projects utilize that measurement. I know Kansas and Oklahoma do so for agriculture, and Missouri while 3 meters is closer to 2 than 10. There are also probably some applications of 2 m with the EPA if I had to guess, similar to 9/2m temp delta calculations. While it may not be useful to the average person assuming they are in an obstructed place, we could argue the same for 10 m wind. It's simply a point measurement we can (I guess) interpolate what it may be where we are.

Honestly, I'd love to have a 2,000ft towers and just litter them with sensors every couple feet from the ground up. Live, high resolution temp and wind data of the whole lower atmosphere! If only there was an unlimited budget! But I digress....

This reminds me of some pictures of a project (that I cannot remember the name of  ](*,)) I found a long time ago.

 [ You are not allowed to view attachments ]

 [ You are not allowed to view attachments ]

Getting PBL data is actually possible with SODAR/LiDAR. I believe the West Texas Mesonet and the NYS Mesonet utilize this technology operationally. Albeit only at select locations as that technology is $$$. I know the NSSL also does this with CLAMPS which is basically a mobile trailer weather station with remote sensing capabilities and with their mobile LiDAR trucks.

Very interesting thoughts nonetheless.

Cheers
Met Instruments Project
CHAD ASOS ID TRX001:
Camp. Sci. CR1000 Logger
R. M. Young 05103L 3M WS/WD
Apogee Inst. ST-110 2M Fast T
R. M. Young 43408 FARS
Vaisala HMT337 2M Td/Ref T
R. M. Young 41003 Gill (x2)
Setra  Sys. 270 StPr (x3)
R. M. Young 52202 Precip
Eppley Lab PSP 3M Solar Rad
PUSR USR-DR404
QuinLED-ESP32
Camp. Sci. CM110
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180 watt PV
300 Ah LiFePO4 Bank
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R. M. Young 26700

Offline havtrail

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Re: 10m Wind Altitude
« Reply #6 on: July 08, 2023, 05:11:18 PM »
It would be interesting to know the results of that study, and see how the wind data at various heights, measured at the same time, varies.

Rich K.
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Offline hofpwx

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Re: 10m Wind Altitude
« Reply #7 on: February 09, 2024, 11:22:33 AM »
I don't know this as fact, but makes complete sense to me. Wind measurement is one of, if not the most important aspects of landing a plane. Given that a median-ish height for air-carrier aircraft control surfaces is about 10 meters AGL, that's why it's measured there.

Does make sense. I'm certainly not in favor of doing away with 10m wind measurements. I just wonder if there's some value of adding a 2m wind in addition.

Honestly, I'd love to have a 2,000ft towers and just litter them with sensors every couple feet from the ground up. Live, high resolution temp and wind data of the whole lower atmosphere! If only there was an unlimited budget! But I digress....


The National Wind Technology Center of NREL has 3 135 meter towers that provide tons of observations from 2, 5, 10, 20, 50 and 80 meters, and they provide one minute resolution data.