InSAR as a Tool to evaluate Peatland Sensitivity to global change

该项目的目的是验证一种新的变革性遥感方法，以实现土壤安全方案的目标，方法是提供对以下方面的更好的和预测性的了解：泥炭在不同地貌和气候背景下在广泛范围内发挥多种功能的能力;泥炭抵抗、恢复和适应气候扰动的能力。这将通过测量泥炭地表面的垂直运动来实现，泥炭地是泥炭体质量（水、气体或有机物）增加或减少的直接指标，也是泥炭土壤状况的有力指标。泥炭占地球陆地碳的1/3，相当于大气中的碳量。泥炭含有高达95%的水和5%的有机物，因此泥炭地及其相关生态系统非常容易受到经济和社会压力以及气候变化的影响。随着泥炭地退化，侵蚀和有机物流失对洪水调节和水质产生不利影响。因此，保护泥炭地是一个优先事项，并在其管理和恢复方面付出了相当大的努力。为了了解泥炭地的威胁并有效地管理泥炭地，我们需要长时间和大面积地考虑泥炭。由于全球和英国境内泥炭地的范围，回答大规模研究问题所需的连续实地监测既困难又昂贵。一种被称为干涉合成孔径雷达的卫星技术利用雷达波测量垂直地表运动。现有的干涉合成孔径雷达技术只能对农村地区提供零星的覆盖，因此对泥炭地无效。我们要测试的是一种新的变革性干涉合成孔径雷达技术，与以往的技术不同，它提供了几乎连续的覆盖所有陆地表面，而不管地面覆盖。因此，这种新方法有可能降低长期监测成本，并通过以下方式指导泥炭地管理决策：1）有针对性地管理泥炭退化区域; 2）评估恢复方法; 3）数据，以实现大面积的有效管理计划。这种新的干涉合成孔径雷达技术的准确性已在固体缓慢移动的表面上得到证明，然而，要实现干涉合成孔径雷达在泥炭上提供的潜力，需要证明结果的现场有效性。这是必不可少的，因为异常动态的泥炭表面可以在短时间内迅速移动，以响应水预算，气体含量，压实和排水的变化。无论哪种方法验证的挑战是，目前没有足够的监测站点足够的程度来验证泥炭地的卫星数据。这种尺度的不匹配是因为干涉合成孔径雷达地图上的单个像素代表的区域为100 × 100 m，这一尺度很少被现场监测所复制。在本提案中，我们将通过解决以下两个研究问题来确定干涉合成孔径雷达测量的有效性1）由干涉合成孔径雷达测量的地面运动是地面运动的幅度和方向的真实指示器吗？2)干涉合成孔径雷达是否显示泥炭地的总体状况？这些问题将通过收集苏格兰流动国家两个地点的土壤状况和表面运动数据来回答，这两个地点是英国最大的土壤碳储存地和欧洲最大的毯子沼泽。选择实地地点是为了补充其他项目，并最大限度地发挥研究的影响和合作的潜力。

The aim of this project is to validate a new and transformative remote sensing method to address the goals of the soil security programme by providing an improved and predictive understanding of; the ability of peat to perform multiple functions in different landscape and climate settings on a wide range of scales; the ability to peat to resist, recover and adapt to climate perturbations. This will be achieved by measuring the vertical motion of the surface of peatland, a direct indicator of mass (water, gas or organic matter) gained or lost from a peat body and powerful indication of peat soil condition.Peat accounts for 1/3 of Earth's terrestrial carbon, a quantity equivalent to the amount of carbon in the atmosphere. Peat contains up to 95% water and 5% organic matter so peatland and its associate ecosystems are highly vulnerable to both economic and societal pressure and climate change. As peatland degrades erosion and organic matter loss have a detrimental impact on flood regulation, and water quality. Consequently, protecting peatland is a priority and considerable effort is being expended on its management and restoration. To understand the threats to peatland and effectively manage peatland requires us to consider peat over long periods of time and large areas. Due to the extent of peatland both globally and within the UK, continuous field monitoring required to answer large scale research questions is both difficult and expensive. Alternative methods are urgently needed.A satellite technique known as InSAR uses radar waves to measure vertical land surface motion. Established InSAR techniques provide only patchy coverage over rural areas and where therefore ineffective over peatland. What we are going to test is a new transformative InSAR technique which unlike previous techniques provides near continuous coverage across all land surfaces irrespective of ground cover. This new approach therefore has the potential to reduce long term monitoring cost and guide peatland management decisions by enabling 1) targeted management of degrading areas of peat 2) evaluation of restoration methods 3) data to enable effective management plans for large areas. The accuracy of this new InSAR technique been demonstrated over solid slow moving surfaces however to realise the potential that InSAR offers over peat the field validity of the results needs to be demonstrated. This is essential as the unusually dynamic peat surface can move rapidly over short periods of time in response to changes in water budget, gas content, compaction and drainage. The challenge validating by either approach is that there are currently not enough monitored sites of sufficient extent to validate the satellite data over peatland. This mismatch of scale arises because a single pixel on an InSAR map represents an area 100x100m a scale rarely replicated by field monitoring.In this proposal we will determine the validity of the InSAR measurements by addressing the following two research questions1) Is the ground motion measured by InSAR a true indicator of the magnitude and direction of the ground motion?2) Does the InSAR indicate the general condition of the peatland? These questions will be answered by collecting data on soil condition and surface motion from two sites in Scotland's Flow Country the single largest soil carbon store in the UK and the largest blanket bog in Europe. Field sites have been chosen to complement other projects and maximise the impact of the research and the potential for collaboration.