Spectral Regularity And BRDF Model Of Typical Crops In The Middle Reaches Of Heihe River

Previous major study is to measure the spectral reflectance of the canopy leaf scale or scales, but also extended to the landscape or global scales using satellite telemetry data on vegetation index calculated. As for the difference between the two has been a hot research. One potential method is to use both connections automated site-scale remote sensing platforms, continuous observation with high spatial and high temporal and high spectral resolution of ground reflection data.In all kinds of basic data pre-processing (including spectral reflectance data, video camera data, the carbon flux data, ET data), analyze photosynthetically active radiation spectral vegetation index and2GRB index Camera extracted,(PAR) index, gross PRImary productivity (GPP), evapotranspiration (ET) correlation, finally establish the spectral reflectance data BRDF models.The Paper has the following conclusions:1) spectrometer extracted by vegetation index analysis found that different types of vegetation indices showed different trends and different vegetation indices showing the same type similar trend; same observation when different azimuth observation zenith, the same time the vegetation index consistent trends. Picture of Camera extracted2G_RB analysis found,2G_RB index under different observation azimuth trends mean in the same period of roughly the same;2G_RB day under different azimuth observations mean dramatic changes in the trend curve when the difference is obvious.2) carbon fluxes:GPP and PAR changes in trends, the day on a single day, the values are lower in the morning and evening when the value is relatively high noon, the overall inverted U-shaped; Curve as a whole is concerned, July GPP undulating curves greater than in August and June. GPP values on different dates but in the same period higher than in August and June. Each Par curve have different growth periods, specifically, the highest value of different days is different, highest there is also a different time value, but because of different weather conditions, ground corn field Par also different. And each growth period of NEE show U-shaped, the difference is not obvious at night NEE data, forming a gentle curve in the vicinity of0.25, due to the difference of temperature, moisture and crop conditions, the clear differences between daytime NEE data, corn in breeding period, daytime NEE data slightly less than0, approximate a straight line daily data, along with corn continues to grow daily data fluctuate constantly increasing, July15is maximized. Evapotranspiration (ET):measuring the concentration of CO2in the ground, the height of the study within40m of the same time in different data values are basically the same height; at the same time, one day mean surface temperature thermal infrared radiation, soil heat flux net radiation similar trend curves but have different peak time point and a high value, and changes of status are related to solar radiation.3) The extent of vegetation index data fit with GPP were lower, the general trend of vegetation index carotenoids> chlorophyll content related to vegetation index> Common vegetation index (NDVI, PRI)> with Flowers astaxanthin related vegetation index> water-related vegetation index; vegetation index data with PAR were lower degree of fit, the general trend is: vegetation index carotenoids> anthocyanin associated with vegetation index> common vegetation index (NDVI, PRI) chlorophyll content related to vegetation index> water-related vegetation index;2GRB index and GPP good fit from the whole extent of the number of equations in the linear equation fit, better than hyperbolic equations from the whole.4) Tracing point location map is generally a plurality of concentric arcs, Dense point linear spectral camera to track the trajectory of satellites; value is the interval between PRI-0.02to0.05, Interval NDVI value is between0.3to0.7,The surface structures of NDVI and PRI’s BRDF at different growth period showed different trends, and point values are different in each direction with the position of different internal surface.