## 3 A Comprehensive Monitoring System for Landslides in 'Space-Sky-Ground-Underground'
### Temperature distribution inside inclinometer tubes B1, B3, and B5
This research provides an important reference for the genetic mechanism and early warning prevention of single landslides on reservoir banks such as the Xinpu landslides. To reduce the impact of atmospheric changes on ground-based interferometric synthetic aperture radar (GB InSAR) deformation monitoring, [PERSON] et al. modelled the atmospheric phase based on the actual geographical environment of the Xinpu landslide. They proposed a two-stage semi-empirical model to estimate the atmospheric phase of each layer to eliminate atmospheric phase changes in the spatial domain. It was proven to reduce the atmospheric phase error by up to 2 mm compared to conventional methods, providing an important reference for the foundation monitoring of the Xinpu landslide [53]. Figure 17: The geographical location of the Xinpu landslide. In addition, the author's research group conducted a large number of experimental studies on the underground monitoring of the Xinpu landslide, especially on strain and temperature monitoring. Landslides are constantly influenced by the surrounding air temperature, water temperature, and ground surface temperature, which, in turn, cause changes in their internal temperature. Usually, the shallow layer of landslides is greatly affected by the temperature, while the deep layer is relatively less affected. The temperature field can affect the permeability coefficient and strength of the slope soil, which can induce slope instability. [PERSON] [54] found that as the temperature increases, the viscosity of pore water in the soil decreases, and the permeability coefficient of the soil increases with the increase in temperature. [PERSON] et al. [55] held the belief that the primary determinants of water movement in soil are the saturation water conductivity and the matrix potential at the wetting front. Furthermore, the authors posited that as temperature rises, the soil water conductivity also exhibits an upward trend. [PERSON] et al. [56] conducted extensive field tests to simulate the effects of seasonal cycling and heating on clay properties over an extended period. Their findings reveal several key insights: Firstly, prolonged exposure to high temperatures causes soil to undergo hardening, altering its physical characteristics. Secondly, as temperatures rise, the soil's moisture content diminishes, leading to an enhancement in its strength properties. Lastly, the study highlights an intriguing trend in the shear strength of clay, which initially decreases with temperature elevation before reversing course and increasing. These observations offer valuable insights into the dynamic behaviour of clay under varying thermal conditions. In short, the temperature will lead to changes in the physical parameters inside the landslide such as the lithology of rock and soil mass, the coupling state of rock and soil mass, and the seepage coefficient. In addition, it will also affect the monitoring accuracy of sensors buried in the landslide. To verify the applicability and accuracy of multi-field monitoring sensors for landslides, experimental research on underground temperature and strain monitoring of landslides was carried out according to the terrain and topography of the Xinpu landslide. Three in-situ boreholes were drilled in the experiment. PT100 temperature sensors and FBG sensors were used as supplementary  
Figure 18: Monitoring of the Xinpu landslide based on the ‘Space-Sky-Ground-Underground’ monitoring technology. means of temperature and strain monitoring. The actual on-site layout plan is shown in Figure 19.  
The temperature field changes from 0:00 on 2 February 2021, to 23:00 on 10 February 2022, obtained in the experiment are shown in Figure 20. The temperature changes at 0.2 m, 0.4 m, 0.6 m, 0.8 m, 1.0 m, 1.2 m, 1.4 m, 1.6 m, 1.8 m, and 2.0 m underground of landslides over time were obtained. It can be concluded that external climate change significantly impacts the temperature field of the underground rock and soil of landslides, especially for the shallow soil of landslides.