Determining regional-scale carbon losses from tropical peatlands using ISBAS-InSAR.

印度尼西亚和马来西亚80%的泥炭地（占地球土壤碳的15%）现在被用于生产纸浆和棕榈油。泥炭分解和大规模森林火灾的相关增加现在是全球温室气体排放的重要贡献者。然而，这些过程中的碳损失和泥炭地排水的影响在整个东南亚仍然很难量化，因为具有挑战性的规模和密集的热带泥炭地森林难以进入。因此，基于实地的沉降测量是评估热带泥炭地碳损失的一种空间有限的方法。天基平台为定期和有效的泛区域监测提供了机会。卫星干涉合成孔径雷达（干涉合成孔径雷达）是一种测量地表运动的技术，其发展有可能解决这一问题。一种新的“间歇性小基线子集”（ISBAS）建模技术，在诺丁汉大学开发，提供了良好的覆盖几乎所有的土地表面，无论地面覆盖。这使得能够长期测量整个流域，地区和国家的泥炭地表面运动。重要的是，ISBAS技术能够使用C波段干涉合成孔径雷达数据确定热带森林树冠下的地表变形，从而能够在90 × 90米的空间尺度上连续监测0.1 - 40厘米/年的地表运动。因此，天基国际合成孔径雷达衍生的运动应与热带泥炭地的碳损失直接相关，从而能够对否则无法到达的热带泥炭地的碳损失进行泛区域评估。这是一种新的方法，因为干涉合成孔径雷达还没有被用于确定热带泥炭地的沉降。该项目旨在确定干涉合成孔径雷达测量的泥炭表面沉降率是否是东南亚热带泥炭地碳损失率的替代指标。干涉合成孔径雷达和沉降的实地测量将与使用统计回归建模技术的泥炭碳储量数据相结合，以验证沉降作为碳损失替代物的使用。

80% of peatland in Indonesia and Malaysia (15% of Earth's soil carbon) is now drained for production of pulpwood and palm oil. Associated increases in peat decomposition and large-scale forest fires are now significant contributors to global greenhouse gas emissions. However, carbon losses from these processes and the impact of peatland drainage remain poorly quantified across SE Asia because of the challenging scale and inaccessibility of dense tropical peatland forests. Field-based subsidence measurements are therefore a spatially limited approach for assessing carbon losses from tropical peatlands. Space-based platforms offer the opportunity for regular and efficient pan-regional monitoring. A development in satellite interferometric synthetic aperture radar (InSAR), a technique that measures surface motion, has the potential to solve this problem. A new 'intermittent small baseline subset' (ISBAS) modelling technique, developed at the University of Nottingham, provides excellent coverage across almost all land surfaces irrespective of ground cover. This enables long term measurement of peatland surface motion across whole catchments, regions and countries. Importantly, the ISBAS technique is able to determine surface deformation under tropical forest canopy using C-band InSAR data, enabling continuous monitoring of surface motion ranging from 0.1 - 40 cm/yr at spatial scales 90x90m. Thus, space-based InSAR-derived motions should directly relate to tropical peatland carbon loss, allowing pan-regional assessment of carbon loss from otherwise inaccessible tropical peatlands. This is a novel approach as InSAR is yet to have been used to determine subsidence of tropical peatland sites. This project aims to determine whether rate of subsidence of the peat surface measured by InSAR is a proxy for rate of carbon loss in tropical peatlands in SE Asia. InSAR and field measurements of subsidence will be combined with peat carbon stock data using statistical regression modelling techniques to validate the use of subsidence as a proxy for carbon loss.