To calculate today's daylength and photoperiod. Daylength is calculated following the treatment of Sellers, Physical Climatology,pp 15-16 and Appendix 2. Daylength is calculated with a correction for atmospheric refraction equivalent to 50 minutes of a degree. Photoperiod is calculated assuming that light is perceived until the centre of the sun is 6 degrees below the horizon. This is a submodel of AFRC Wheat 2 model in Simile notation (the XML version will follow shortly). All variables and parameters that are inputs to the submodel are in the "inputs " submodel box, all variables changed by the submodel are outputted via the "outputs" submodel box.
Porter J (1993). AFRCWHEAT2: A Model of the Growth and Development of Wheat Incorporating Responses to Water and Nitrogen. . Eur. J. Agron. 2(2): 69-82..
Originally submitted to PLaSMo on 2011-02-04 15:46:39
Created: 10th Jan 2019 at 17:39