Biogeochemical geography of peatlands from in-situ measurements to satellite imagery

泥炭地在全球碳循环以及维持生物多样性和保护濒危物种方面发挥着重要作用。北部泥炭地储存了三分之一来自大气二氧化碳的陆地碳。然而，与其他陆地生态系统相比，对它们的结构和功能的了解要少得多。尽管泥炭地具有复原力，但它们很容易受到气候变化、干扰和土地利用变化的影响。需要在景观尺度上（以及随着时间的推移）准确地了解它们的结构和功能，以便为有关它们的管理和保护的政策提供信息。遥感和地理空间建模为在大空间尺度上更好地了解这些生态系统提供了机会。我的研究项目旨在通过遥感数据填补泥炭地生物地球化学地理学的关键知识空白。我的长期目标是：1)确定遥感泥炭地植被特征从原位测量到卫星图像的转换效果；2)根据气候变化预估改进泥炭地碳平衡成像光谱模型。四个科学问题指导我提出的研究计划：1)在机载高光谱图像获取过程中，泥炭地的各向异性反射率如何受到光照条件（即太阳方位角和天顶角）的影响？2)考虑物候，泥炭地植被面相分类的光谱变异性是什么？3)利用泥炭地的光学图像确定地下水位位置（或替代位置）的精度如何，从而在大空间尺度上模拟净生态系统交换？4)在气候变化预估的基础上，泥炭地不同植被类型的分布范围将如何变化？据估计，加拿大有12%的国土面积是泥炭地，因此加拿大有明确的管理义务。该研究项目的结果将增加对该生态系统作为气候变化调解者和基本生态系统服务提供者的重要性的认识。

Peatlands play a significant role in the global carbon cycle as well as in the maintenance of biodiversity and the protection of endangered species. Northern peatlands store one third of the terrestrial carbon derived from atmospheric carbon dioxide. Nevertheless, far less is known about their structure and function in comparison to other terrestrial ecosystems. Despite their resilience, peatlands are vulnerable to climate change, disturbance and land use change impacts. Precise information about their structure and functioning at landscape scales (and over time) is needed in order to inform policy regarding their management and conservation. Remote sensing and geospatial modelling offer the opportunity to better understand these ecosystems at large spatial scales through time. My research program aims to fill key knowledge gaps regarding the biogeochemical geography of peatlands from remotely sensed data. My long-term objectives are: 1) To determine the effect of scaling remotely sensed vegetation characteristics of peatlands from in-situ measurements to satellite imagery; and 2) To improve models of peatland carbon balance from imaging spectroscopy in light of projected climate change. Four scientific questions guide my proposed research program: 1) How is the anisotropic reflectance of peatlands affected by the illumination conditions (i.e. solar azimuth and zenith angle) during acquisition of airborne hyperspectral imagery? 2) Considering phenology, what is the spectral variability of peatland vegetation physiognomic classes? 3) With what precision can we determine the water table position (or a proxy) from optical imagery for peatlands as a means to model net ecosystem exchange at large spatial scales? and 4) Based on projected climate change, how will the extent of the different vegetation physiognomic classes change across the peatland? With 12% of its surface area estimated to be peatland, Canada has a clear stewardship obligation. The results from this research program would increase the understanding of the importance of this ecosystem as a climate change mediator and provider of fundamental ecosystem services.