Analysis of the Variation of Photoperiod with Latitude and Season
Abstract: An analysis is conducted of the relation of the photoperiod on the earth with its rotation and rev-olution. The seasonal change of the photoperiod is also interpreted based on the mutual relation. Furthermore, upon analyzing the geometrical sun-earth relation as well as the day and night change on the earth, a formula is established to describe the relationship of the photoperiod and the observation location for any time of the year. With this formula, the seasonal and the geographical variation of the photoperiod can be predicted, and the phenomenon of the polar day and the polar night can be well interpreted. Finally, the formula has been applied to discuss the mean photoperiod of some representative cities in China in January and July. The prediction accuracy of the formula is evaluated upon comparing the calculated value of the photoperiod to the true value of Beijing.
文章引用: 苑中显 , 辛 凤 , 杜春旭 (2014) 日照时长随地理纬度及季节的变化关系。 可持续能源， 4， 41-50. doi: 10.12677/SE.2014.44007
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