The difference between surface and 1000mb geopotential height
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@vujacicm said in The difference between surface and 1000mb geopotential height:
1000mb geopotential is then 400m under surface.
Not realy!
Please read my (7 yrs old) posts !
https://community.windy.com/topic/5014/windspeed-and-direction-different-heights/2?_=1596783618621
and
https://community.windy.com/topic/4831/aviation-winds-aloft-on-airgram/4?_=1681921025576
It is about wind at various levels but, also, wx. models work tha same way for temperature.
Also keep in mind (because of steep mountains in your area)
for ECMWF, the elevation for Bovec (model elevation) is 1142m !!!
(some 700 m higher than the real one).
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@Gkikas-LGPZ Does this mean that also on Mount Everest can be 1000mb?
Is here reason, why temperature in Windy is lower then station shows, because is 1142m high?
Maybe I have troublle to understand difference between pressure and geopotential height. This mean that on top od the mountain can be 1000mb geopotential height, but not 1000mb pressure.
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@Gkikas-LGPZ Looks like that air pressure and geopotential height is not the same thing. This mean that on top of Mounth Eversr can ne 1000mb geopotential heights, but not air pressure.
If I am right, air pressure tells you, how away you are from sea level and geopotential height, how away you are from surface.
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@Caefix Here is the map of Himalayas.
Surface -13 Celzius
850mb 17 Celzius
How everywhere higher then Himalayas surface temperature can be higher then on surface?
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@vujacicm
The temperature at surface is the temperature at ground level (about 2m). The temperature variation is important, the sun heating the soil during the day and the soil cooling during the night due to radiative effect.
The temperature at 850hPa is the air mass temperature at this elevation i.e. in free atmosphere. The variation during one day is not so important. -
@idefix37 It's not 18 degress too hot for 9000m elevation or even higher?
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@vujacicm said in The difference between surface and 1000mb geopotential height:
850mb 17 Celzius
850hPa is not 9000m, only 1500m !
By the way, here we are on the forum community of windy.com. So why all your posts show screenshots from another weather app ?! -
@idefix37 Mounth Everest is 9000m height. How can there be 850mb on 1500m?
On Windy is simillar
Surface -5
850mb 20
On Meteoblue I can show the temperature on the point, on Windy I can only show temperature with colours.
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@vujacicm
See what is the vertical structure of the grid points in a weather modelhttps://community.windy.com/topic/5014/windspeed-and-direction-different-heights/2?_=1724610259822
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@vujacicm
In Windy, you can see precisely the temperature of a point.
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@idefix37 I am to slow with screenshot. It's gone, before I scan.
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@idefix37 You are showing me the winds. What about temperature? Does 20 degress on 850mb still cross surface of Mounth Everest?
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@vujacicm
The winds ? The title of my screenshot is Temperature and -7°C is not a wind speed ! -
@idefix37 This, what you give me, is about winds
https://community.windy.com/topic/5014/windspeed-and-direction-different-heights/2?_=1724610259822
I see that understanding geopotential height is not easy, that's reason, why a lot of questions.
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@vujacicm
I should have only shown this graph.
It should allow you to understand what is the temperature at 850hPa above Mount Everest.
Note also there is sometime a big difference between the real elevation and the model elevation. -
@idefix37 So, model elevation shows that there is 18 Celzius let's say 500m above Mount Everest surface?
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In the mountains, global models are wrong because their orography model is too coarse compared to the reality of the terrain.
It is exactly what @Gkikas-LGPZ explained to you in his post here Bové
You should therefore not try to focus on high mountains with global models. -
@idefix37 What I see on 850mb, I can say that on that level the surface of this mountain is adiabaticaly heated on this level. If this is not true, then is really just wrong, how you say.
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@idefix37 It looks like you are right, if geopotential is lower then mountain, it will not show right
