Local and nonlocal topographic controls on landscape ecohydrology

本研究的总体目标是统计量化的相对重要性的本地与非本地地貌景观代谢控制在复杂的地形不同的水文气候强迫和地质年龄，和量化的非线性和阈值效应的程度。该研究的指导下的假设，当地和nonlocal地形景观代谢的影响的相对重要性，根据水文气候条件的变化。此外，这种转变的条件与景观年龄和相关的表面平滑过程，修改的相对重要性的尾巴与地形特性（方面，坡度，贡献面积等）的分布模式的变化。该研究将使用统计场理论对景观进行理论描述，并分析对氯化萘循环（辐射、土壤特征、植被覆盖和土壤水分动态）的本地和非本地控制。最后，它将耦合本地和非本地控制的土壤地球化学动力学，扩展以前的随机土壤水分和土壤地球化学模型，包括空间随机组件。控制植被和土壤养分动态的基本环境过程以及相关的碳和氮通量（也称为景观代谢）与土地能量和水收支有关。 本研究分析了这些过程，并量化了它们在空间和时间上的差异，作为本地和非本地景观特征的函数，如坡度，方向和流域面积。这一建议将为更根本地了解河流流域和山区等复杂景观在不同空间尺度上的碳、氮和水通量规律铺平道路。该项目将有助于为全球气候模型量化地表条件，特别是在气候和土地使用情景变化的背景下。

The overarching goal of this research is the statistical quantification of the relative importance of local vs. nonlocal geomorphologic controls on landscape metabolism in complex topographies differing in hydroclimatic forcing and geologic age, and the quantification of their degree of nonlinearity and threshold effects. The research is guided by the hypothesis that the relative importance of local and nonlocal topographic effects on landscape metabolism shifts according to hydroclimatic conditions. Moreover, the conditions for such shifts change with the landscape age and the related surface smoothing processes, which modify the relative importance of tails vs. mode of the distributions of topographic properties (aspect, slope, contributing area, etc.). The research will provide a theoretical description of landscapes using statistical field theories, and analyze local and nonlocal controls on CN cycles (radiation, soil features, vegetation cover, and soil moisture dynamics). Finally it will couple local and nonlocal controls to biogeochemical dynamics, extending previous stochastic soil moisture and biogeochemistry models to include spatially random components. The fundamental environmental processes controlling vegetation and soil nutrient dynamics and the related carbon and nitrogen fluxes (also called landscape metabolism) are related to the land energy and water budgets. This research analyzes such processes and quantifies how they differ in space and time, as a function of the local and nonlocal landscape features, such as slope, orientation and drainage area. This proposal will pave the way to a more fundamental understanding of the laws for carbon, nitrogen, and water fluxes at different spatial scales over complex landscapes such as river basins and mountain regions. The project will be instrumental for the quantification of the land surface conditions for global climate models, especially in the contexts of variation in climatic and land-use scenarios.