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Solar Radiation
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| In the ferry application, the pyranometer is used to measure total downward solar radiation, while the reflected upward component will be estimated using observed values of albedo over the ocean. The model CM 21 is an ISO-class instrument, which means it meets one of the categories outlined in the ISO 9060 standard. For instance, the cosine directional response and the temperature dependence are verified criteria. The incoming radiation is received by the sensing element housed under two concentric glass domes, and coated with a stable carbon based non-organic, which allows a good spectral absorption and a long term stability. The role of the inner hemisphere is to filter wavelength of 305 to 2800 nm. In addition to the black unit, a second built-in sensor detects and compensates any change in body temperature, so that the response is independent of ambient temperature. Thus, the temperature sensed is nearly linear with the flux density of incident radiation, with less than 0.25% of reported non-linearity for incoming shortwave under 1000 W/m². The use of this pyranometer in combination with Kipp & Zonen CV2 Ventilation system reduces instrument maintenance, and offers better measurement performance. |
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| The solar sensor as depicted on the Kipp & Zonen website. |
The solar sensor is secured on top of the mast attached to the port side bridge wing. |
The solar sensor, shown in the upper left portion of the picture, is housed within a ventilator and attached to the top of the bridge wing mast. |
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