Method for improving business nuclear drive bidirectional reflectance distribution function (BRDF) model hot spot

Abstract

The invention relates to a method for improving a business nuclear drive bidirectional reflectance distribution function (BRDF) model hot spot. The method comprises the following steps: a new volume scattering nucleus considering the hot spot change is put forward through carrying out the hot spot calibration on the volume scattering nucleus of a conventional MODIS business nucleus drive BRDF model RTLSR, an RTCLSR model generated by the linear combination of the nucleus with an original geometrical optics nucleus has preferable fitting capability to the hot spot, but the fitting precision in the other observation directions is not influenced, a POLDER-3/BRDF database and onboard CAR data are used to carry out calibration and verification on the hot spot parameters of the RTCLSR model, the new RTCLSR model is available to study the change of the hot spot effect with earth surface category, NDVI and a solar zenith angle, meanwhile, the new model maintains the linear form of an original model very well, and the complexity of model calculation is not greatly increased, so that a new algorithmic base and a solution provided for the MODIS BRDF/ albedo business product up-gradation is made into possible. The method for improving the business nuclear drive bidirectional reflectance distribution function (BRDF) model hot spot has significant application value in the technical field of spatial information, in particular to the aspect of quantitative remote sensing.

Description

1. Technical field [0001] The invention relates to a method for improving hotspots of a business kernel-driven bidirectional reflection distribution function (BRDF) model, which belongs to the technical field of spatial information. 2. Background technology [0002] The anisotropic reflection of the earth's surface is a basic macroscopic phenomenon of the reflection of electromagnetic waves by objects in nature. The study of the distribution function of the ditropic reflection of the earth's surface is an important part of the field of optical quantitative remote sensing research. Since the 1970s, satellite remote sensing has mainly adopted vertical observation to obtain surface information. With the in-depth study of remote sensing mechanism, the development of remote sensing technology, and various new demands, people are increasingly aware that multi-angle remote sensing provides an additional effective source of information in obtaining surface information by means of re...

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Problems solved by technology

[0003] Although this model has been widely used, one of the main shortcomings of this model is that it underestimates the hotspot effect

The early solution to this problem is to multiply the expression of the model by a hotspot kernel. Although this method has a certain effect on the correction of the hotspot effect, the main problems are: (1) the isotropic parameter (f iso ) is mainly an expression of the optical properties of the ground object, which determines the level of the overall reflection of the target rather than the change of the target reflection mode with the angle, so the hotspot kernel function cannot be applied to this parameter; (2) Li's sparse and reciprocal geometry The optical kernel has already described the hotspot effect well, so it should be excluded from the hotspot kernel correction, and no secondary correction is necessary; (3) The estimation of the hotspot by the corrected model is still low; (4) This correction method changes the original model The linear structure of , which increases the computational complexity, due to the nonlinear characteristics of this hot spot correction, we exclude the comparison of this model in the study

The recent progress in this area also involves the overlapping function theory based on Jupp and Strahler, through the development of a hotspot factor to correct the volume scattering kernel, so as to construct a new model, which we call the RTJLSR model, but the problems with this correction model are: ( 1) When the sun and the observation are in the direction of the zenith, the isotropic scattering parameter (f iso ) loses its physical meaning as albedo in the original model; (2) this correction does not take into account that hotspots may be affected by different surface types, NDVI, and solar zenith angle variations

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