Net radiation of short- and long-wave radiation has been recorded continuously during 1962–64 and monthly data are presented. Net long-wave radiation is determined as difference between recorded net short-wave and net total radiation. Net long-wave radiation has also been calculated according toMonteith [1] and close agreement was found between the two methods. An improved net radiometer having a 30 windings half copper-plated constantan thermopile is described. It is not influenced by ambient temperature variation and yields an output of 8 mV for a net radiation of 1 cal cm−2 min−1. The thermopile is shielded by 0.04 mm polyethylene hemispheres, continuously pressurized by dry nitrogen gas and outside symmetrically ventilated. The difference of 4 per cent in sensitivity to short- and long-wave radiation is eliminated by white strips.