Lower than Expected Cave Air Temperature

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Lower than Expected Cave Air Temperature

Postby CaveHound » Jul 13, 2016 11:36 am

I have a question concerning a newly discovered cave in Middle Tennessee. Strong air flow is coming from the entrance (recently dug) at a temperature of 47 degrees F. Other caves located within a one mile radius have a temperature in the 56-57 degree F range. What can account for this 10 degree temperature difference?
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Re: Lower than Expected Cave Air Temperature

Postby Leclused » Jul 15, 2016 5:41 am

Is there a strong wind going in during the winter? And is there a lot of tubical passage? So in the winter the cold from the air (freezing temp?) can lower the tempt of stone dramatically. The cold is accumulated in the rock. When the airflow turns around and begins blowing the accumulated cold is gradualy released and lowers the air temp. So measure the temp of the rock to see if this is lower then normal average yearly temp of location of the cave.

It also can be that it is a 'Cold air trap'. (see 1.6.5 and further in the first link below)

Some good reference work about airflows in caves (in French) is called "Vent de Ténèbres"

http://cds38.org/wp/wp-content/uploads/ ... -tome1.pdf

http://cds38.org/wp/wp-content/uploads/ ... -tome2.pdf
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Re: Lower than Expected Cave Air Temperature

Postby struebe » Jul 15, 2016 2:38 pm

There are also cases where flowing water can cool down cave air temperatures.

Have you calculated or researched what mean annual temperature at the area you're speaking of is? It's possible that the other caves are warmer than expected for some reason like decay of organic material, or a lack of circulation seasonally.
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Re: Lower than Expected Cave Air Temperature

Postby trogman » Jul 16, 2016 1:26 am

The 56 - 57 degree cave temp is about what is normal for middle TN. It does sound like what is known as a cold air trap. This phenomena occurs in other caves; one that comes to mind is Fern Cave in AL, where a cold air trap creates an optimal environment for the huge colony of bats that roost there. I am not personally familiar with what sort of dynamics cause this condition. However, if your newly opened cave has this condition, I wonder if it's an indication of impressive size and/or length, perhaps on the same order as Fern Cave?

You didn't mention how long this cave is, or if there seems to be potential for finding more passage. If at all possible, follow that air! Best wishes!

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