Analysis of peatland carbon dynamics using combined optical and microwave satellite data

利用光学和微波卫星数据相结合的泥炭地碳动态分析

• 批准号: 2286072
• 金额: --
• 依托单位: University of Reading
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2286072
• 关键词: Analysis; peatland; carbon; dynamics; using

This project aims to develop remote sensing schemes for examining the resilience of restored peatlands to drought conditions, particularly of different peatland microforms, through the plant photosynthetic response to drought and rewetting.Peatlands are a key component of the terrestrial carbon cycle. They sequester large amounts of carbon from the atmosphere. Peat-forming plants, and especially bryophytes such as Sphagnum mosses, are well adapted to this wet environment but suffer disproportionally in dry conditions. Many peatlands in the British Isles have been subject to deleterious management schemes, including drainage, overgrazing, planting for commercial forestry, and burning. Although large-scale restoration efforts have now been implemented, it is often challenging to completely restore the hydrological characteristics of such sites. This leaves them vulnerable to drought periods, during which markedly negative effects on photosynthesis of peatland vegetation, and ultimately carbon emissions, can be observed. The number of Earth Observation satellites available to study peatlands has risen in the past few years with the advent of the Sentinel-1 and Sentinel-2 missions. The Sentinel-1 satellites carry synthetic aperture radar (SAR) instruments which are sensitive to soil and plant moisture and, critically, are not affected by cloud cover which can often otherwise restrict optical/IR measurements of peatland areas. The Sentinel-2 satellites carry optical instruments that are sensitive to the visible and near infra-red parts of the electromagnetic spectrum. This makes them ideal for monitoring plant health. In future, we will also have direct observations of photosynthesis from the European Space Agency's FLEX Earth Explorer mission (planned launch 2022), which measures Solar Induced Fluorescence (SIF) from plants.The student will investigate the synergistic exploitation of current and future satellite microwave radar, visible, infrared, and SIF platforms for the remote sensing of drought responses of peatlands and test the feasibility of remotely monitoring peatland resilience on a landscape scale. The work falls into three components:1) Laboratory-based study of the drying and rewetting response of different peatland microforms. We will house these experiments on a lysimeter and take regular measurements with UoR's ground-based radar system configured to match Sentinel-1 measurements. Optical measurements to simulate Sentinel-2 will be taken alongside the SAR observations. Together these will be used to calibrate a joint SAR-optical model of drying and rewetting responses 2) Field-based studies of optical and SIF measurements. The student will conduct a field campaign during year 1-2 to monitor restored and non-restored sites with hand-held optical instruments. These data, alongside in-situ soil moisture and gross primary production data (JHI long term eddy covariance monitoring datasets) will allow us to test models devolved in (1). The SIF data will be used to explore the additional benefit of missions such as FLEX. 3) Examine the 2018 drought, which provides an exceptional opportunity to understand the remote sensing signals of peatland water stress. The Sentinel-1 and 2 data for 2018 will be extracted for the Forsinard flows and the impact of the drought of that year on the peatlands will be explored based on the relationships built in (1) and (2).

该项目旨在开发遥感方案，通过植物对干旱和再湿润的光合作用反应，检查恢复的泥炭地对干旱条件的恢复能力，特别是不同泥炭地微形态的恢复能力。泥炭地是陆地碳循环的关键组成部分。它们从大气中吸收大量的碳。形成泥炭的植物，特别是苔藓植物，如泥炭藓，很好地适应了这种潮湿的环境，但在干燥的条件下却受到不成比例的影响。不列颠群岛的许多泥炭地都受到有害的管理计划的影响，包括排水、过度放牧、商业林业种植和焚烧。尽管现在已经实施了大规模的恢复工作，但要完全恢复这些地点的水文特征往往具有挑战性。这使得它们容易受到干旱期的影响，在此期间可以观察到对泥炭地植被的光合作用以及最终的碳排放产生明显的负面影响。过去几年，随着 Sentinel-1 和 Sentinel-2 任务的出现，可用于研究泥炭地的地球观测卫星数量有所增加。 Sentinel-1 卫星携带合成孔径雷达 (SAR) 仪器，这些仪器对土壤和植物湿度敏感，而且最重要的是，不受云层影响，云层通常会限制泥炭地区域的光学/红外测量。 Sentinel-2 卫星携带对电磁波谱的可见光和近红外部分敏感的光学仪器。这使它们成为监测植物健康状况的理想选择。将来，我们还将通过欧洲航天局的 FLEX 地球探索者任务（计划于 2022 年发射）直接观测光合作用，该任务测量植物的太阳诱导荧光（SIF）。学生将研究当前和未来卫星微波雷达、可见光、红外和 SIF 平台的协同开发，用于遥感泥炭地的干旱响应，并测试远程遥感的可行性 在景观尺度上监测泥炭地的恢复力。这项工作分为三个部分：1）基于实验室的不同泥炭地微形态的干燥和再润湿响应研究。我们将在蒸渗仪上进行这些实验，并使用 UoR 的地面雷达系统进行定期测量，该系统配置为与 Sentinel-1 测量相匹配。模拟 Sentinel-2 的光学测量将与 SAR 观测一起进行。这些将一起用于校准干燥和再润湿响应的联合 SAR 光学模型 2) 光学和 SIF 测量的现场研究。学生将在第一年至第二年进行实地活动，使用手持式光学仪器监测已恢复和未恢复的地点。这些数据以及原位土壤湿度和总初级生产数据（JHI 长期涡度协方差监测数据集）将使我们能够测试（1）中的模型。 SIF 数据将用于探索 FLEX 等任务的额外好处。 3) 研究 2018 年的干旱，这为了解泥炭地缺水的遥感信号提供了绝佳的机会。将为 Forsinard 流提取 2018 年的 Sentinel-1 和 2 数据，并根据 (1) 和 (2) 中建立的关系探讨当年干旱对泥炭地的影响。