The pyranometer DRA 153 Lsi-Lastem provides continuous measurements of:

- global solar radiation (W/m2).

The LSI pyranometer is an instrument to measure the global sun radiation (direct and diffuse) which reaches the terrestrial surface. With this instrument it is possible to measure not only the global radiation, but also the reflected sun radiation (albedometer) and the diffuse radiation by means of the occultation band. The solarimeter measures radiation values within 300 and 3000 nm, with a visibility of 2? steradians. The element used to for the measurement is a thermopile whose external surface has been darkened with matte black paint C10 Nextel bearing a reflecting power < than 2% (e>0.98) in the spectral area of the sensor.

Each radiometer is supplied with a Calibration Report produced by comparison, under the sun (ISO 9847), with a radiometer calibrated at the WRC-PMOD in Davos. (WRC: World Radiation Center; PMOD: Phisikalisch Meteorologisches Observatorium Davos;)

Accuracy:

an overall uncertainty value is not supplied; there are however many characteristics available according to the classes of the WMO n°8 and ISO 9060. Besides, the uncertainty of this instrument is influenced by the quick temperature changes owing to the intervention of clouds and rain.

Re-calibration:

It is not necessary to re-calibrate the instrument frequently. It is advisable to re-calibrate the instrument every 2 to 3 years in order to keep calibration uncertainty variations in the range of 5%.