Tarmo
Tue Apr 12 10:52:44 CDT 2005
And I was meaning current temperature and dewpoint... So I don't know, what
was the dewpoint earlier
Tarmo Tanilsoo <tarmo.tanilsoo@mail.ee> wrote in message
news:425938cf_1@news.estpak.ee...
> Hello,
>
> I have only temperature and dewpoint.
>
> Tarmo Tanilsoo
>
> Dr John Stockton <spam@merlyn.demon.co.uk> wrote in message
> news:J8V+D$DkGFWCFwQG@merlyn.demon.co.uk...
> > JRS: In article <42568786$1_2@news.estpak.ee>, dated Fri, 8 Apr 2005
> > 16:30:44, seen in news:microsoft.public.scripting.vbscript, Tarmo
> > Tanilsoo <tarmo.tanilsoo@mail.ee> posted :
> >
> > >How can I use gradation in VBScript? I planned to make a script, what
> > >calculates relative humidity from temperature and dewpoint
> >
> > IIRC, the dewpoint temperature gives the absolute humidity and the
> > temperature gives the possible humidity; just divide the former humidity
> > by the latter and multiply by 100%.
> >
> > To convert from temperature to possible humidity, i.e. to saturation
> > vapour pressure, you can either use a mathematical expression that fits
> > the variation well enough over the range, or you can use a set of data
> > points and an interpolating expression.
> >
> > Looking at a vapour pressure table at 10 degree intervals, I suspect
> > that a linear interpolation would be inadequate but a cubic one
> > satisfactory.
> >
> > P(T) = P3 * (T-T0)(T-T1)(T-T2) / (T3-T0)(T3-T1)(T3-T2) plus three
> > similar terms, used with T0 < T1 <= T <= T2 < T3 .
> >
> > Check the physics : it is some while since I was concerned with
> > humidity.
> >
> > --
> > © John Stockton, Surrey, UK. *@merlyn.demon.co.uk /
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