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Measurement of Long‐Wave Radiant Flux in Organismal Energy Budgets: A Comparison of three Methods
Author(s) -
Campbell G. S.,
Mugaas J. N.,
King J. R.
Publication year - 1978
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1938242
Subject(s) - thermocouple , flux (metallurgy) , radiant flux , dome (geology) , radiometer , thermopile , pyranometer , atmospheric sciences , environmental science , energy flux , meteorology , heat flux , optics , materials science , mechanics , irradiance , geology , physics , composite material , heat transfer , paleontology , astronomy , infrared , metallurgy
Long—wave radian flux density was inferred as the difference between short—wave and total flux, the latter being measured by modifications of 2 commercially available instruments. One of these was a Kipp pyranometer in which the glass domes were placed by a polyethylene dome and a thermocouple was affixed to the bottom of the thermopile. The other was a net radiometer in which the lower polyethylene dome was painted, shaded, and supplied with a thermocouple. Long—wave flux density was measured separately with a custom—made prygeometer, using a commercially available KRS—5 dome. Construction details are given for all 3 instruments. Comparisons through a 4—day span under field conditions showed that the 3 readings of long—wave flux density never differed by >10%, and usually differed by <2—3%, although differences as great as 20 W/m 2 sometimes occurred when short—wave flux was high. Short—wave heating of the dome had a negligible effect on the accuracy of the new pyrgeometer, unlike the commercial model.