Accurate estimate of active layer thickness (ALT) is crucial for understanding permafrost and ecosystem responses to climate change. Interferometric Synthetic Aperture SAR (InSAR) technology can detect active layer freeze-thaw induced surface deformation with high accuracy, facilitating more accurate ALT estimation at the regional scale. Previous studies revealed a positive relationship between ALT and seasonal deformation in poorly drained Arctic soils. However, whether such relationship still holds in arid permafrost regions such as the Qinghai-Tibet Plateau (QTP) remains uncertain. Through synthesizing extensive field observations and remote sensing data, we find an overall negative correlation (r = -0.53, p < 0.01) between ALT and seasonal deformation in QTP, which tends to become more negative with sparser vegetation and drier soils, in contrast to the Arctic. After normalizing the climatic effect on ALT, we observe a decreasing sensitivity of seasonal deformation to active-layer changes with drier soils. Our study reveals a non-linear relationship between ALT and seasonal deformation across different permafrost regions, which helps to inform future development of InSAR-based permafrost applications.

准确估计活动层厚度 （ALT） 对于了解永久冻土和生态系统对气候变化的响应至关重要。干涉合成孔径雷达 （InSAR） 技术能够高精度地检测活性层冻融诱导的表面变形，有助于在区域尺度上更准确地估计 ALT。以前的研究表明，在排水不良的北极土壤中，ALT 与季节性变形之间存在正相关关系。然而，这种关系在青藏高原 （QTP） 等干旱永久冻土区是否仍然存在仍不确定。通过综合广泛的野外观测和遥感数据，我们发现 ALT 与 QTP 中的季节性变形之间存在总体负相关 （r = -0.53，p < 0.01），与北极相比，随着植被稀疏和土壤干燥，季节性变形往往变得更加负相关。 在对 ALT 的气候影响正常化后，我们观察到季节性变形对干燥土壤的活性层变化的敏感性降低。我们的研究揭示了不同永久冻土区 ALT 与季节性变形之间的非线性关系，这有助于为基于 InSAR 的永久冻土应用的未来发展提供信息。