Sandaysoft

Mine is inline with Met Office Guidelines (Thanks to Beteljuice) at 1.5m above Ground Level.
Anno is around 10m above Ground Level.
Rain Bucket is on Flat Surface around 5m above Ground Level (Not recommended but due to Location and Wiring).

I think I did read somewhere, that When the air is 2.8C the Ground is 0.0C. So, you could in theory use a formula based script where, when Temp is (Whatever) subtract 2.8 and output is Ground Temp (Whatever Temp is -2.8C) - So in short -- <#temp> - 2.8 = <#groundtemp>

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Jason Duncombe
La-Crosse WS2300 (Wired & Serial) - Cumulus V1.9.3
Check out the Weather Blog

An example of a PHP Solution:

Ground Temperature: <?php $sum_total=$temp-2.8; print(sum_total); print ($tempunit); ?>

An example of a JavaScript Solution:

Will be available very soon

Enjoy

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Jason Duncombe
La-Crosse WS2300 (Wired & Serial) - Cumulus V1.9.3
Check out the Weather Blog

Warning - Danger Will Robinson !

That is a very rough approximation for a gauge at 'standard' height, above grass, and clear night temperatures

Any and every site will be different, and will be affected by cloud cover.

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......................Imagine, what you will KNOW tomorrow !

Ah yes -- Thank you Beteljuice for the 'Heads Up'

As Beteljuice has said, The -2.8C Approximation & My Php Script is 'Very Rough' and depends on a number of Variables - Clear Night, Temperature Sensor Height and Site.

Hopefully through this MAYBE we can come up with SOMETHING but the real answer is a Purpose Built Device.

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Jason Duncombe
La-Crosse WS2300 (Wired & Serial) - Cumulus V1.9.3
Check out the Weather Blog

It is a VERY complicated subject, all to do with thermal dynamics, boundary layers etc.etc.

.. and the rules change for eg. lying snow (like now) and even more devious for permafrost !

However, under 'normal' cold / frost a good general explanation (and pointing the difference reverses in daylight) is here: http://www.bbc.co.uk/weather/features/u ... rost.shtml

_________________

......................Imagine, what you will KNOW tomorrow !

I wouldn't worry about the differences...

You do the best you can do with the equipment and sitting you have available.

It is likely more important that you maintain the same configuration and location so that you have good relative data from day to day, month to month over the seasons that you can compare like type settings when the year rolls around.

Many "Official" sites are not what one would consider perfect sitting locations (like over concrete for example) but they are the same as they have been for years and are the record of that area.

You might find that the accuracy of your instrument isn't within the difference anyway.

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Kevin

All you need is Time, Aptitude and Desire ... and you can build just about anything...
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