total solar irradiation: | (300-2800 nm) |
measurement precision: | 10%, |
total solar irradiation | 300-2800 nm, |
measurement precision | 8% |
sensitivity | 9-15 microV/Wm-2 |
impedance | 70-100 Ohm |
response time (1/e value) | 5 s |
99% value after | 55 s |
ambient operating temperatures | -40 to +60 deg C |
max irradiance | 2000 W/m2 |
cosine response | < -/+ 7% (percentage deviation from ideal at 10 deg solar elevation on a clear day) |
azimuth response | < -/+ 5% (percentage deviation from the mean at 10 deg solar elevation on a clear day) |
nonlinearity | -/+ 2% (percentage of full scale) |
measurement precision | 5% |
total solar irradiation | 295-2800 nm or in defined wavelength bands dependent on a type of Schott fitler used: WG295 (295-2800 nm), GG395 (395-2800 nm), GG495 (495-2800 nm), OG530 (530-2800 nm), OG570 (570-2800 nm), RG610 (610-2800 nm), RG630 (630-2800 nm), RG695 (695-2800 nm), RG715 (715-2800 nm), RG780 (780-2800 nm). |
sensitivity | 9 microV/W m-2 approx. |
impedance | 650 Ohm approx. |
receiver | circular 1 cm-2, coated with Parsons' black optical laquer |
linearity | -/+ 0.5% from 0 to 2800 W/m2 |
temperature dependance | -/+ 1% over ambient temperature range -20 to +40 deg C |
response time (i/e value) | 1 s |
cosine | -/+ 1% from normalization 0-70 deg zenith angle |
orientation | no effect on instrument performance |
Measurement precision under the conditions of low solar radiation level (<100 W/m2)
or low solar altitude (h < 20 deg) may be lower than given above.
Apart from the errors caused by the pyranometers precision and the instability of
the electronic unit (especially amplifiers) the main sources of the measurement
errors on the ship are: low precision of instruments levelling and shading by
the masts (r/v Oceania case). The influence of the list and well as rolling and
pitching of the ship is considerably reduced by mounting the pyranometers on
Cardan suspensions.
Three Eppley pyranometers are mounted on a common platform with Cardan
suspension and a levelling device.
Kipp&Zonen pyranometer is placed on a separate Cardan suspension without
a levelling device, 2 m from the Eppley's.
The measurement precisions given above comprise all the error sources except
shading by the masts.