干旱区生态环境知识资源中心

The modelling technique contributes to understanding noise nature and properties. Prior work has established a primary random noise model in the homogeneous medium, however, this strict assumption of the medium may be not valid under the actual environment so that will reduce the modelling accuracy. Therefore, in this paper, a random noise model is established in the mixed heterogeneous medium to improve the modelling accuracy, so the scattered mechanism is used to describe the random noise field in the heterogeneous medium. Since the perturbation method is always applied to solve the scattering problem, the noise wave field can be regarded as the superposition of the perturbation wave field and the unperturbation wave field. Consequently, the random noise model reveals that the desert random noise is mainly caused by the wind, and it concentrates on 1-20 Hz. A detailed comparison is made between the noise model established in the homogeneous medium and the proposed noise model, the results illustrate that the proposed noise model is more similar to the actual noise. Besides, for embodying the model's practical application value, the proposed noise model is adopted as the background noise to determine the VMD (variational mode decomposition) denoising parameters. The satisfactory denoising performance supports the usefulness of the proposed noise model for the random noise attenuation.