Relative pressure in Graphweather

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TREVIS75
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Inscription : jeu. oct. 16, 2008 8:43 pm

Relative pressure in Graphweather

Message par TREVIS75 »

Hi,
I am using graphweather 2.0.250b with heavyweather and LaCrosse WS2300.
I do not understand why the relative pressure on Graphweather is different than that displayed on Heavyweather.
In order to change should increase / decrease the altitude in option / general / location.
There is no other way without changing the height?
thanks
TREVIS75
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Inscription : jeu. oct. 16, 2008 8:43 pm

Re: Relative pressure in Graphweather

Message par TREVIS75 »

If I use the "probe correction" utility for relative pressure, what values should I put in the spaces? :roll:
Antonio
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TiToine
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Re: Relative pressure in Graphweather

Message par TiToine »

The pressure should be the same if it's the relative pressure.
Absolute pressure is calculated with altitude, the GW model is not exactly the same as HW, therefore the pressure could be a little be different.

In probe correction, for example:
Value corrected = 2 * Value + 10
If Value = 1000hPa, Value corrected = 2010 hPa
TREVIS75
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Inscription : jeu. oct. 16, 2008 8:43 pm

Re: Relative pressure in Graphweather

Message par TREVIS75 »

GW in the absolute pressure is equal to that shown on heavyweather ... while the relative pressure is different.
For example: the height of my country is about 9 meters, the relative pressure on GW is 997.7 hPa while heavyweather shows me 1000.7 hPa ... To adjust the pressure on GW need to bring the height to 37 meters!
I tried to use the probe correction with the formula but does not work ... :cry:
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jturlier
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Re: Relative pressure in Graphweather

Message par jturlier »

TREVIS75 a écrit :GW in the absolute pressure is equal to that shown on heavyweather ... while the relative pressure is different.
For example: the height of my country is about 9 meters, the relative pressure on GW is 997.7 hPa while heavyweather shows me 1000.7 hPa ... To adjust the pressure on GW need to bring the height to 37 meters!
I tried to use the probe correction with the formula but does not work ... :cry:
Hello,
you should consider that 9m elevation is close to sea level, a usual eval of the delta is elevation * 0.120482 it gives around .86 hPa per 10 meters.
So if I were you I would seriously questionned the heavyweather value.
As a verification you could check an airport close to the town you live in, when the isobare lines are very spaced.
Anyway unless your station is wrongly calibrated, you should not apply a correction greater than 1 hPA
Jean

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