Concept information
Preferred term
PYRANOGRAPHS
Definition
- Pyranographs measure changes in solar radiation by a mechanism similar to that in the hygrothermograph. The differential shrinking and expanding of two bimetallic strips causes a pen to move up or down against a rotating drum, recording changes in solar radiation. Both strips are exposed to the ambient air temperature, but one strip is shielded from the direct rays of the sun and the other is exposed. The pen moves when the temperature of the exposed strip increases beyond that of the shielded strip, i.e. when direct radiation from the sun causes it to heat up and expand. The pen does not move when both strips are changing temperature at the same rate in response to changes in the ambient air temperature. In effect, the shielded strip is the baseline and solar radiation is measured as any change in the exposed strip that exceeds that baseline. Additional information available at "http://www.hubbardbrook.org/yale/watersheds/w6/rain-gauge-stop/ temperature.htm" [Summary provided by Hubbard Brook] (en)
Broader concept
URI
https://gcmd.earthdata.nasa.gov/kms/concept/c35d861f-7877-4cfa-9a55-e1722047efc6
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