Wind strengths and headings
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Wind strengths and headings
Can someone help me with a good rule of thumb for calculating the amount of wind increasing and decreasing by altitude ( from surface to say 2000ft )
I know wind will veer with increase in altitude and back with decrease in altitude, but by how much??
Please help
G-XO
I know wind will veer with increase in altitude and back with decrease in altitude, but by how much??
Please help
G-XO
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Compared to the 'official' 10m wind, 30% stronger and 30 degrees veered (+30) at 1000 feet is a good rule of thumb assuming unstable well mixed air.
But it could be completely rubbish on a day with high stability (or for any one of a host of other reasons).
And the wind may well be much less at 2 or 3 metres off the ground (the bit you are landing in).
But it could be completely rubbish on a day with high stability (or for any one of a host of other reasons).
And the wind may well be much less at 2 or 3 metres off the ground (the bit you are landing in).
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There is no rule of thumb! its not like temperature lapse rates - which arent even accurate anyway(mostly for engineering and met vague calulations).
the weather and wind particularily depends on so many different variables. u can never tell. it varys from day to day, hour to hour and minute to minute.
the weather and wind particularily depends on so many different variables. u can never tell. it varys from day to day, hour to hour and minute to minute.
Last edited by JohnGV; 3rd Oct 2008 at 06:16.
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yea, i'd agree that there isn't much of a useful rule for that as you probably well know it varies with speed and direction constantly throught the day and night.
but what's given in the Met syllabus as a "rule of thumb" for this is that from 2000ft AGL to the surface the wind backs by around 30 degrees and speed drops to about 50%. ...only applies overland though dut to friction layer...is a seperate one for over sea.
but what's given in the Met syllabus as a "rule of thumb" for this is that from 2000ft AGL to the surface the wind backs by around 30 degrees and speed drops to about 50%. ...only applies overland though dut to friction layer...is a seperate one for over sea.
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Exactly:
A rule of thumb is a useful approximation:
Not a rule of mathematical certainty.
30 degrees and fifty percent works well.
Who ever said that Met was a precise science.
Cusco.
A rule of thumb is a useful approximation:
Not a rule of mathematical certainty.
30 degrees and fifty percent works well.
Who ever said that Met was a precise science.
Cusco.
Avoid imitations
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Wind may have Direction or even Track but never Heading!
Thanks very much guys, I passed today with 90%.
So thats 3 exams done and hopefully another 2 by the end of this month.G-XO
