Method for estimating yield of winter wheat by assimilating characteristics of leaf area index time-sequence curve

Abstract

The invention discloses a method for estimating the yield of winter wheat by assimilating the characteristics of a leaf area index time-sequence curve. The method is implemented through the following steps: S1, performing global sensitivity analysis on a crop model and completing parameter regionalization of the crop model; S2, synthesizing the MODIS LAI (moderate resolution imaging spectroradiometer leaf area index) time-sequence curve; S3, performing filtering processing on the LAI time-sequence curve; S4, performing curve fitting and extracting key characteristic points; S5, operating the crop model in area coverage, performing curve fitting on the LAI time-sequence curve obtained by simulation and extracting the key characteristic points on the curve; and S6, establishing a cost function according to dates of three key characteristic points which are respectively obtained in S4 and S5, taking remote sensing observation error as weight for summating and further getting a total cost function, minimizing the total cost function to rapidly converge the cost function, and finally gathering according to an administrative boundary when convergence conditions are met and outputting a yield result. According to the method disclosed by the invention, the assimilation precision is improved, the affects caused by the situation that an MODIS LAI product system is lower are overcome and the method is further suitable for estimating the yield of the winter wheat at regional scale.

Description

technical field [0001] The invention relates to the technical field of agricultural remote sensing, in particular to a method for estimating winter wheat yield by assimilating the characteristics of the time series curve of leaf area index. Background technique [0002] In the application process of crop yield estimation, crop models based on crop photosynthesis, respiration, transpiration, nutrition and other mechanism processes can accurately simulate the continuous evolution of crop objects in time and space by relying on their inherent physical processes and dynamic mechanisms, and can accurately Simulate the growth and development status and yield of single-point crops. When applied to the regional scale, due to the non-uniformity of the surface and near-surface environments, it is very difficult to obtain some macroscopic data and regionalize parameters in the model. The satellite remote sensing method has the advantages of spatial continuity and temporal dynamic chan...

AI Technical Summary

Problems solved by technology

However, in the main production areas of winter wheat in North China, due to the low spatial resolution of MODIS data, the mixed pixel effect is serious, resulting in systematically low errors in MODIS LAI products, and direct assimilation of MODIS LAI products will lead to worse assimilation effects

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