Advances in Research and Application of Techniques for Measuring Photosynthetically Active Radiation

Photosynthetically Active Radiation (PAR) is a critical indicator of plant photosynthesis and ecosystem energy flux. Accurate measurement of PAR is essential in agriculture, ecological research, and environmental management. This paper reviews recent developments and applications of PAR measurement technologies, focusing on recent advances in commercial PAR sensors, low-cost sensors, and remote sensing techniques. First, we outline the definition of PAR and further discuss in situ measurements and indirect estimation approaches. The technical principles, sources of error, and practical applications of commercial PAR sensors are presented at the next section. On the contrary, we also introduce the potential of low-cost sensors, particularly emphasizing the role of citizen science initiatives and open-source technologies in promoting widespread PAR measurement. Furthermore, the technical principles underlying remote sensing-based PAR estimation on a global scale are summarized, along with the application prospects of machine learning and satellite-derived product analysis techniques. Finally, this paper comprehensively reviews the challenges confronting PAR measurement and explores potential sensor innovations that may arise from future technological advancements.