Peatlands in tropical regions like Indonesia are undergoing irreversible subsidence due to changes in land use (e.g., deforestation) and land management practices (e.g., drainage alteration), resulting in massive amounts of soil carbon loss. Several satellite-borne synthetic aperture radar (SAR) sensors are operating concurrently at different frequencies, providing potentially useful data for monitoring surface motion over tropical peatlands. This study focused on the capability of C-band (SENTINEL-1) and L-band (PALSAR-2) SAR data to monitor the surface changes in the tropical peatlands area of Bengkalis Island, Indonesia, by applying time-series interferometric SAR (InSAR) with the small baseline subset (SBAS) technique. The average vertical velocity measured by SENTINEL-1 and PALSAR-2 for the period of 2018–2019 was −1.41 and −2.65 cm yr⁻¹, respectively. We also explored the potential of groundwater level (GWL) data converted to vertical displacement for validating SBAS InSAR. PALSAR-2 performed the best, exhibiting lower RMSE values for each land use compared to SENTINEL-1, with an overall RMSE of 1.383 and 1.988 cm yr⁻¹, respectively. Also, the subsidence rates of SENTINEL-1 were underestimated, showing a significantly lower mean subsidence difference (0.96 cm yr⁻¹) than the reference. Our GWL-based subsidence data offered an alternative validation method for InSAR-based subsidence estimation. Therefore, the integration of time-series InSAR and GWL data can provide crucial information for monitoring the degradation of tropical peatlands.

中文翻译：

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基于时间序列SBAS InSAR技术，使用多频（C波段和L波段）SAR数据监测泥炭沉降

由于土地利用（如森林砍伐）和土地管理实践（如排水系统改变）的变化，印度尼西亚等热带地区的泥炭地正在发生不可逆转的沉降，导致大量土壤碳流失。几个星载合成孔径雷达 (SAR) 传感器同时以不同频率运行，为监测热带泥炭地的表面运动提供了潜在有用的数据。本研究重点研究了C波段（SE​​NTINEL-1）和L波段（PALSAR-2）SAR数据应用时间序列干涉SAR监测印度尼西亚Bengkalis岛热带泥炭地地区地表变化的能力（ InSAR) 与小基线子集 (SBAS) 技术。SENTINEL-1和PALSAR-2在2018-2019年期间测量的平均垂直速度为-1.41和-2.65 cm yr^-1，分别。我们还探讨了将地下水位 (GWL) 数据转换为垂直位移以验证 SBAS InSAR 的潜力。PALSAR-2 表现最好，与 SENTINEL-1 相比，每种土地使用的 RMSE 值都较低，总体 RMSE 分别为 1.383 和 1.988 cm yr ^-1。此外，SENTINEL-1 的沉降率被低估了，显示出比参考显着更低的平均沉降差（0.96 cm yr ^-1）。我们基于 GWL 的沉降数据为基于 InSAR 的沉降估计提供了一种替代验证方法。因此，时间序列 InSAR 和 GWL 数据的整合可以为监测热带泥炭地退化提供关键信息。