Simulation of photosynthetically active radiation distribution in algal photobioreactors using a multidimensional spectral radiation model

2014 ◽  
Vol 158 ◽  
pp. 141-148 ◽  
Author(s):  
Bo Kong ◽  
R. Dennis Vigil
2008 ◽  
Vol 35 (10) ◽  
pp. 867 ◽  
Author(s):  
Xiping Wang ◽  
Yan Guo ◽  
Xiyong Wang ◽  
Yuntao Ma ◽  
Baoguo Li

The three-dimensional (3-D) radiation distribution model in plant canopy is pivotal for understanding and modelling plant eco-physiological processes. Diffuse and direct radiations penetrate into plant canopies in different ways and may present different intensity and wavelength composition. Sunfleck (the canopy surfaces where the direct radiation reaches) distribution in the plant canopy is usually regarded as an important index for crop development, especially under dense canopy conditions. Distributions of direct and diffuse components of photosynthetically active radiation (PAR) in maize (Zea mays L.) canopies were estimated respectively using a 3-D incident radiation model (3DIRM). The 3DIRM model was set up for computing incident radiation in crop canopies by applying a parallel-projection based submodel for direct solar radiation and a central-projection based submodel for incident diffuse radiation simulation in crop canopy. It was well assessed with a field experiment with multi-point PAR measurement in maize canopies with relative errors of 2.6, 4.5 and 2.6%, respectively, for sunfleck area ratio, diffuse PAR and total PAR. The results suggest that the 3DIRM model could be used to estimate the direct, diffuse and total PAR at any specific surface part in the 3-D canopy space. The exponential distinction model for direct, diffuse and total PAR along with leaf area index in different heights in maize canopies was also evaluated based on the 3DIRM simulation results.


Author(s):  
Александр Васильевич Празукин ◽  
Юрий Константинович Фирсов ◽  
Александр Александрович Латушкин ◽  
Анна Алексеевна Чепыженко

Морские травы экологически важны, но чрезвычайно уязвимы перед антропогенными изменениями в прибрежных зонах, которые влияют на доступность света в этих экосистемах. При разной высоте Солнца над горизонтом в зондирующем режиме проводилось одновременное измерение значений температуры воды и интенсивности фотосинтетически активной радиации (IPAR) по профилю полога Zostera noltii Hornemann (высота полога 32 см.) в мелководной части Казачьей бухты (г. Севастополь, Черное море, 44°57′26″ с.ш., 33°40′33″ в.д.). Для полога Z. noltii характерен одномодальный тип вертикального распределения биомассы с максимумом (65,7 г (сухой массы) / м2) в его нижней части. Рассматривается изменение температурной стратификации и распределения IPAR по профилю растительного полога Z. noltii в течение светового дня. Seagrass is environmentally significant but extremely vulnerable in coastal areas to anthropogenic changes, which affect light availability. Simultaneous measurements of water temperature and photosynthetically active radiation (PAR) intensity in the sounding mode were taken at different solar elevation angles for the Zostera noltii Hornemann canopy (canopy height 32 cm) in shallow waters of the Cossack Bay (Sevastopol, the Black Sea, 44°57′26″ с.ш., 33°40′33″ в.д.). Z. noltii canopy is characterized by a unimodal type of biomass vertical distribution with its maximum (65,7 g (dry matter)/m2) in the lower part. Temperature stratification and IPAR distribution changes within the Z. noltii vegetation canopy profile during daylight hours are considered.


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