Analysis On Solar Radiation's Characteristics Inside And Outside Of The Greenhouse Around The Shaanxi Yang Ling Area

From March to December in 2015,the plastic film greenhouse,PC greenhouse,Float glass greenhouse and outdoor of the South Campus of Northwest A & F University was used to measure solar radiation spectrum at the spring equinox,the summer solstice,the autumn equinox and the autumn solstice by PS-300 spectrometer in Shaanxi Province..The spectral characteristics of solar radiation inside and outside the greenhouse under different seasons and different materials in Yangling District were analyzed.The main conclusions are as follows:(1)During the spring equinox and autumnal equinoxes,the cloud has a great influence on the PAR and total radiation in the greenhouse,which is only about 50% of the typical sunny days in the typical cloudy days.During the winter solstice,the influence of cloud layer on PAR and total radiation in greenhouse was slight,but in typical sunny days it was only more than that in typical cloudy days.(2)The spectra of different wave bands in greenhouse declined to the winter solstice at the beginning of autumn and the total radiation in the winter solstice is15.51% of the summer solstice.;(3)EVA plastic film PAR transmission performance was the most outstanding,followed by the float glass,and finally for the polycarbonate plate.Ultraviolet light transmittance compared with the outdoor control group The results for the float glass> EVA plastic film> polycarbonate,the impact of factors,far-red light translucent performance polycarbonate sheet ? EVA plastic film> glass,the gap is small.Material itself is the core of the impact of sources,such as structural shading is the secondary source of influence;(4)PAR all day and the total radiation wave curve,the most smooth winter solstice,the overall shape was normal distribution pattern,sooner or later obvious changes,reaching noon at 12 o'clock.The autumn equatorial curve is also smooth,with the extreme at 1 pm and a sharp rise at 10 a.m.,with a sharp downward trend at 4 a.m.The vernal equinox value at2:00 pm,with the same fall score,changed greatly at 10 a.m.and 4:00 p.m.,and remained at a high level between 10 a.m.and 4 p.m.for the most favorable photosynthesis.(5)The overall PAR change From the point of view of summer solstice,the autumnal equinoxes were higher than the equinoxes,all of them were much larger than that of the winter solstice.The daily variation curves of the sunny day were single peaked extremum and smoother,and the diurnalexcursion curves had the lower extremes,Due to intermittent clouds caused by obstruction.