Tl. Stoffel et al., Current issues in terrestrial solar radiation instrumentation for energy, climate, and space applications, METROLOGIA, 37(5), 2000, pp. 399-402
Uncertainty in terrestrial solar radiation measurements of a few watts per
square metre (1 W/m(2) to 2 W/m(2)) is needed to validate estimates of the
Earth's radiation balance derived from satellite data. The characterization
of solar energy resources for renewable energy technologies requires simil
ar accuracy for economical technology deployment. Solar radiation measureme
nt research at the National Renewable Energy Laboratory addresses calibrati
ons, operational characteristics, and corrections for terrestrial solar rad
iation measurements. The characterization of field instrument geometric and
thermal responses contributing to radiometric errors is described, togethe
r with correction schemes reducing the uncertainty of broadband irradiance
measurements from tens of watts per square metre to a few (+/- 2 W/m(2) to
+/- 5 W/m(2)). Such improvements in accuracy reduce the time and labour req
uired for detecting and quantifying trends in terrestrial solar radiation a
cid possible changes in the Earth's radiation budget.