Continuous measurements are made using a Kipp & Zonen CNR4 net flux radiometer. It measures both downwelling and upwelling radiation in 2 wavelength bands which are common to many similar instruments. A shorter wavelength band measures radiation received from the sun. It encompasses the visible spectrum, together with near infrared and longer wavelength ultraviolet, over a wavelength range of approximately 0.29 - 2.8 µm. It shows a clear response to the day/night cycle. Clouds and other aerosols reduce the detected radiation. A longer wavelength band measures longer wavelength infrared radiation (approximately 4.5 - 32 µm) produced by emission from the atmosphere and earth's surface. It does not respond significantly to the day/night cycle but changes according to the time of year and degree of cloud cover.