Remote monitoring method for soil moisture of wheat field

Abstract

The invention discloses a remote monitoring method for soil moisture of a wheat field. A corrected thermal inertia model is W=B1*ATI+B2*EVI+B, wherein W is relative soil water content; ATI is apparent thermal inertia; B1 and B2 are coefficient items; EVI is an enhanced vegetation index; and B is a constant item. In the method, the closing actions of wheat plants on the soil background are fully considered, and an enhanced vegetation index which is sensitive to vegetation reflection in a low-vegetation covering area is introduced and is taken as a vegetation influencing factor according to a thermal inertia process during inversion of soil moisture by using EOS / MODIS (Embedded Operation System / Moderate Resolution Imaging Spectroradiometer) remote sensing data. The average inversion accuracy of a corrected thermal inertia model can be over 80 percent before ridge sealing of wheat. According to comparative analysis of the synchronous inversion result of the conventional thermal inertia model, the corrected thermal inertia model has higher inversion accuracy, and a suitable time domain is expanded by about one growth period.

Description

technical field [0001] The invention relates to a remote sensing monitoring method for soil moisture in a wheat field. Background technique [0002] At the end of the 1960s, a lot of research was carried out on remote sensing monitoring of soil moisture at home and abroad. The main methods are: thermal inertia method, vegetation water supply index method, greenness index method, anomaly vegetation index method and microwave remote sensing method. Various methods choose different remote sensing information sources and use different bands, and have their own scope of application and limitations. [0003] The thermal inertia method is a relatively mature soil moisture remote sensing monitoring method. The principle is based on the fact that thermal inertia is a thermal characteristic of the substance itself. The thermal inertia of soil is closely related to the moisture content in the soil. The heat capacity and thermal conductivity of soil increase with the increase of soil m...

AI Technical Summary

Problems solved by technology

When the farmland is bare land, the MODIS image can truly reflect the spectral characteristics of the surface soil; when the vegetation coverage gradually increases, affected by the canopy effect of plant leaves, the performance of the surface soil characteristics on the satellite image is disturbed, and the accuracy of the model inversion significantly reduce

During the wheat cultivation process, the soil coverage of the field is changing. During the tillering, overwintering and greening periods after wheat emergence, the wheat is in the seedling stage, and the vegetation coverage in the field is low. At this time, it is still not suitable to switch to the plant growth principle However, at this time, the wheat seedlings have inevitably formed a certain canopy effect on the soil, and the monitoring accuracy of the conventional thermal inertia model is bound to decline.

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