scholarly journals Transmission of ultraviolet, visible and near-infrared solar radiation to plants within a seasonal snow pack

2019 ◽  
Vol 18 (8) ◽  
pp. 1963-1971 ◽  
Author(s):  
T. Matthew Robson ◽  
Pedro J. Aphalo
Keyword(s):  
Solar Radiation ◽  
Ultraviolet Radiation ◽  
Photosynthetically Active Radiation ◽  
Near Infrared ◽  
Snow Pack ◽  
Active Radiation ◽  
Seasonal Snow ◽  
Better Than

Ultraviolet radiation is transmitted better than longer wavelengths through the upper centimetres of a seasonal snowpack, where about 10% of the incident photosynthetically active radiation reaches 7 cm depth.

scholarly journals Radiación fotosintéticamente activa evaluada en la ciudad de Zacatecas

2020 ◽  
pp. 1-11
Author(s):  
Mónica Montserrat Escobedo-Sánchez ◽  
Ricardo Conejo-Flores ◽  
Sergio Miguel Durón-Torres ◽  
Juan Manuel García-González
Keyword(s):  
Decision Making ◽  
Solar Radiation ◽  
Production Planning ◽  
Photosynthetically Active Radiation ◽  
Detailed Knowledge ◽  
Active Radiation ◽  
Incident Solar Radiation ◽  
Daily Average ◽  
Life On Earth

The present investigation is related to one of the most important processes for the development of life on Earth; photosynthesis, an essential process in the cycle and development of living beings, centered on solar radiation that is useful for plants to carry out this process, Photosynthetically Active Radiation (PAR). The objective of this work is to generate information on the PAR through a database to collaborate in the decision-making of farmers in the area. For this purpose, a quantum sensor installed in building 6 of the UAZ Siglo XXI Campus was used. According to Abal (2013), in agricultural and production planning, it is especially important to have a detailed knowledge of incident solar radiation on the earth's surface (Abal and Durañona, 2013). When collecting, treating and analyzing the data, it was found that the daily average PAR is 819.52 μmol of photons m-2 s-1 (179.47 W m-2), if only the sunny hours are taken into account. It can be concluded that according to the PAR received in the evaluation region and the type of nutrients in the soil, other crop alternatives to those traditionally used can be sought.

scholarly journals A Photovoltaic Greenhouse with Passive Variation in Shading by Fixed Horizontal PV Panels

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3269 ◽  
Author(s):  
Simona Moretti ◽  
Alvaro Marucci
Keyword(s):  
Solar Radiation ◽  
Photosynthetically Active Radiation ◽  
Natural Variation ◽  
Elevation Angle ◽  
Fixed Position ◽  
Mathematical Relationship ◽  
Photovoltaic Panels ◽  
Active Radiation ◽  
Autumn And Winter ◽  
Interesting Solution

The traditional shading systems that greenhouses use cause some of the solar radiation that is reflected or absorbed to be lost and, therefore, not used by the plants under cultivation. An interesting solution to these problems is to position photovoltaic (PV) panels on the roofs of greenhouses. All of the photovoltaic greenhouses that have been realized in Mediterranean areas are characterized by a fixed position of the PV panels and excessive shading, especially in autumn and winter. The purpose of this study is to describe a prototype of a photovoltaic greenhouse with both fixed and horizontal PV panels that exploit the natural variation in the elevation angle of the sun’s rays during the year to allow for “passive” variation in shading. The considerable variation in the elevation angle of the sun’s rays (from 24.4° to 71.1°) results in a high variation in shading (from 39.4% to 72.6%), with the highest values in the summer months and the lowest values in the winter months. This trend is favorable for meeting the photosynthetically active radiation (PAR) needs of greenhouse plants. If the plants under cultivation require more solar energy, it is necessary to increase the distance between the panels. We implement a specific mathematical relationship to define the precise distance to be assigned to the photovoltaic panels on the roof pitch.

A Generalized Relationship between Photosynthetically Active Radiation and Solar Radiation 1

1984 ◽  
Vol 76 (6) ◽  
pp. 939-945 ◽  
Author(s):  
D. W. Meek ◽  
J. L. Hatfield ◽  
T. A. Howell ◽  
S. B. Idso ◽  
R. J. Reginato
Keyword(s):  
Solar Radiation ◽  
Photosynthetically Active Radiation ◽  
Active Radiation

scholarly journals Cumulative Effects of Ultraviolet Radiation and Photosyntheically Active Radiation on Phycobiliproteins of A Hot-Spring Cyanobacatrium Nostoc sp. strain HKAR-2

2016 ◽  
Vol 4 (3) ◽  
pp. 247-253
Author(s):  
Vinod K. Kannaujiya ◽  
Akhlaqur Rahman ◽  
. Adinath ◽  
Arun S. Sonker ◽  
Jainendra Pathak ◽  
...  
Keyword(s):  
Ultraviolet Radiation ◽  
Environmental Conditions ◽  
Photosynthetically Active Radiation ◽  
Biomedical Applications ◽  
Hot Spring ◽  
Ultraviolet B ◽  
Cumulative Effects ◽  
Key Factors ◽  
Active Radiation ◽  
Continuous Induction

Cyanobacteria are cosmopolitan in distribution and have adapted to diverse habitats. Adaptation of cyanobacteria is one of the key factors to withstand harsh environmental conditions. We have investigated the effects of photosynthetically active radiation (PAR; 400–700 nm), ultraviolet-B (UV-B; 280–315 nm) radiation and PAR+UV-B radiations on phycobiliproteins (PBPs) of a hot-spring cyanobacterium Nostoc sp. HKAR-2. There was a continuous induction of both phycoerythrin (PE) and phycocyanin (PC) after exposure of PAR up to 300 min. However, there was an induction in the synthesis of both PE and PC up to 240 min exposure of UV-B and PAR+UV-B radiations. Further exposure showed decline in the synthesis due to rapid uncoupling, bleaching and degradation of PBPs. Similarly, emission fluorescence also showed an induction with a shift towards longer wavelengths after 240 min of UV-B and PAR+UV-B exposure. These results indicate that short duration of UV radiation may promote the synthesis of PBPs that can be utilized in various biotechnological and biomedical applications. Int J Appl Sci Biotechnol, Vol 4(3): 247-253

scholarly journals Microclimate under different shading screens in greenhouses cultivated with bromeliads

2012 ◽  
Vol 16 (8) ◽  
pp. 858-863 ◽  
Author(s):  
Ester Holcman ◽  
Paulo C. Sentelhas
Keyword(s):  
Relative Humidity ◽  
Solar Radiation ◽  
Air Temperature ◽  
Photosynthetically Active Radiation ◽  
External Condition ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Net Radiation ◽  
Active Radiation ◽  
Incoming Solar Radiation

This study had as its objective the evaluation of the influence of shading screens of different colors on the different microclimate variables in a greenhouse covered with transparent low-density polyethylene (LDPE). The experiment was conducted with five treatments: thermo-reflective screen (T1); a control - without screen (T2); red screen (T3); blue screen (T4); and black screen (T5), all of them with 70% of shading. An automatic micrometeorological station was installed in each treatment, measuring air temperature (T), relative humidity (RH), incoming solar radiation (Rg), photosynthetically active radiation (PAR) and net radiation (Rn) continuously. The control (T2) and red screen (T3) treatments promoted the highest solar radiation transmissivity, respectively 56.3 and 27%. The black screen (T5) had the lowest solar radiation transmissivity (10.4%). For PAR and Rn the same tendency was observed. The highest temperature was observed under blue screen (T4) treatment, which was 1.3 °C higher than external condition. Blue screen (T4) treatment also presented the highest relative humidity difference between inside and outside conditions.

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