Kipp & Zonen Net Radiometer CNR4
The Kipp & Zonen CNR4 is a net radiometer that measures the radiation energy balance using two pyranometers for short-wave radiation and two pyrgeometers for long-wave radiation, mounted back-to-back to capture both incoming and outgoing (reflected) solar and infrared radiation. Built-in Pt-100 and thermistor temperature sensors correct the infrared readings for instrument housing temperature.
- Supply
- 12 VDC, 1.25 A with heater on (CNF4 ventilation unit)
- Spectral range – short-wave
- 0.3 to 2.8 µm (300 to 2800 nm)
- Spectral range – long-wave
- 4.5 to 42 µm (4500 to 42000 nm)

Overview
In detail
How it works
Two pyranometers measure short-wave radiation and two pyrgeometers measure long-wave radiation. Positioned back to back, the four sensors measure both incoming and outgoing (reflected) solar insolation to provide the energy balance. Each sensor is individually calibrated for optimal accuracy.
Construction
The top long-wave detector has a meniscus dome so water droplets roll off easily and the field of view increases to nearly 180°, up from 150° for a flat window. A Pt-100 and a thermistor provide temperature information to correct the infrared readings for the temperature of the instrument housing, aiding datalogger compatibility. The CNR4 and NR Lite2 both meet WMO standards.
Ventilation (CNF4)
The optional CNF4 ventilation unit with heater extends the sun shield and can be fitted to a new CNR4 or retrofitted. It provides efficient air-flow over the domes and windows to minimise dew formation and reduce cleaning frequency, and its integrated heater melts frost.
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Specifications
Technical specifications
- Spectral range – short-wave
- 0.3 to 2.8 µm (300 to 2800 nm)
- Spectral range – long-wave
- 4.5 to 42 µm (4500 to 42000 nm)
- Sensitivity
- 5 to 20 µV/W/m²
- Response time
- < 18 s
- Non-linearity
- < 1 %
- Operating temperature
- -40 to +80 °C (CNR4); -40 to +70 °C (CNF4)
- Supply voltage
- 12 VDC, 1.25 A with heater on (CNF4 ventilation unit)
- Ventilation power
- 5 W continuously
- Heating power
- 10 W, externally switched
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