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Grass/Concrete Minimum Thermometers

PostPosted: 2011 Dec 21, 21:04
by Mike Brown
The observers handbook indicates they should be read in the morning, and then stored inside until the evening (1800z) ob. Is this current practice with everyone or are they just left out. I guess many who are measuring the values will use electronic means nowadays and so have to leave them out. Perhaps those with traditional instruments could let me know please?

Best wishes


Re: Grass/Concrete Minimum Thermometers

PostPosted: 2011 Dec 22, 13:00
by Martin Rowley
... I follow the Observer's Handbook procedure - actually setting just before sunset rather than waiting until 1800z. However, if the minimum temperature (grass) has yet to occur at 0900z, I read the thermometer, noting that as the grass minimum at 09z, then leave the thermometer in place to capture the lowest value that might be yet to occur. In this case I reset it again, after noting the lowest value, as above.

I also leave the grass minimum out when there is a snow cover - lifting it up as per instructions if it is covered by an overnight / current snowfall. This is to monitor the behaviour of the temperature over the snow surface.