A Study On Effect Of Water Background On Canopy Spectral Of Wetland Aquatic Plant

The wetland is in the transition zone of land and water, it has abundant land and aquatic plants and animals, and it plays an important role in maintaining the global ecological balance. Aquatic vegetation is the core of the wetland ecosystem, and it’s also the main factor influencing the wetland ecosystem functions. Aquatic plant communities protect the biological diversity of aquatic environment. Aquatic plants for photosynthesis, carbon fixation and oxygen release at the same time, but also absorb many of the harmful elements in the water body, restore the ecological function of water body. In recent years, satellite remote sensing technology has been widely used in the investigation, classification and protection fields of wetland vegetation resources. But problems still exist, such as low classification accuracy of aquatic vegetation, poor accuracy of inversion and so on. Because of the unique growth environment of aquatic vegetation, its canopy spectral will be affected by water background factors, the air-water interface and water sediment, plankton and transparency, water depth, sediment and other optical active components. The application of remote sensing technology in wetland aquatic vegetation canopy spectral study, we must consider the terrestrial vegetation and aquatic vegetation in different growing environments. This paper choose a typical water plant (Iris tentorium Maxim) as the research object, simulate the growth environment of wetland aquatic plants, use the feature spectrometer measurements the spectral reflectance of Iris tentorium Maxim vegetation canopy under different coverage, different water depth gradient, different sediment types background(400nm-2400nm). Experimental results show that, there was a significant correlation between the canopy spectrum of aquatic vegetation and the background factors of water:canopy reflectance decreased with the decrease of vegetation coverage of iris, there was a positive correlation between the canopy reflectance and vegetation coverage, the spectral characteristics of the green vegetation is lost when the coverage is 0; with the increase of background depth, iris vegetation canopy reflectance decreased, there was a negative correlation between the canopy reflectance and water depth; the canopy spectral characteristics of aquatic vegetation are different in different background. This study can provide the correction for field survey of aquatic vegetation spectral data reference, eliminate water background influence on vegetation canopy spectrum, in order to get more real aquatic vegetation spectral data. Through further analysis, the establishment of coverage and water depth with the linear regression equation between aquatic vegetation canopy spectra, for according to the aquatic vegetation canopy spectral data to estimate the background factors of the water body.