Measuring floodplain spatial patterns using continuous surface metrics at multiple scales
Measuring floodplain spatial patterns using continuous surface metrics at multiple scales
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DOI：
10.1016/j.geomorph.2015.05.026
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发表时间：
2015-09
期刊：
影响因子：
3.9
通讯作者：
M. Scown;M. Thoms;N. D. Jager
中科院分区：
文献类型：
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作者：
M. Scown;M. Thoms;N. D. Jager
河流过程和洪泛平原生态系统之间的相互作用发生在往往物理上复杂的洪泛平原表面上。泛滥平原地形的空间格局最近才在多个尺度上被量化，而且泛滥平原表面被认为是如何在空间上组织的存在差异。我们测量了美国密西西比河上游9号池的泛滥平原地形的空间格局，使用移动窗口分析8个表面指标，应用于多个尺度上的1×1×1/m2DEM。使用的指标是Range、SD、偏度、峰度、CV、SDCURV、粗糙度和Vol：Area，窗口大小半径从10到1000微米。整个泛滥平原的地表度量值变化很大，并揭示了泛滥平原地形的高度空间组织。Moran的I相关图对每个窗口大小下的景观进行了拟合，表明几乎所有窗口大小都存在斑块，但斑块的强度和尺度在窗口大小内发生变化，这表明该泛滥平原的地形存在多个尺度的斑块和斑块结构。观察到空间模式中的比例阈值，特别是所有表面指标的50至100微米窗口尺寸之间以及大多数指标的500至750微米窗口尺寸之间。这些门槛尺度分别为主槽宽度的15%~20%和150%(滩地宽度的1%~2%和10%~15%)。这些阈值可能与跨不同规模范围运行的结构化过程有关。通过将地表度量、多尺度分析和相关图结合起来，可以量化泛滥平原地形的复杂性，这种方式应该有助于澄清泛滥平原生态系统的结构。
Interactions between fluvial processes and floodplain ecosystems occur upon a floodplain surface that is often physically complex. Spatial patterns in floodplain topography have only recently been quantified over multiple scales, and discrepancies exist in how floodplain surfaces are perceived to be spatially organised. We measured spatial patterns in floodplain topography for pool 9 of the Upper Mississippi River, USA, using moving window analyses of eight surface metrics applied to a 1 × 1 m2DEM over multiple scales. The metrics used wereRange,SD,Skewness,Kurtosis,CV,SDCURV,Rugosity, andVol:Area, and window sizes ranged from 10 to 1000 m in radius. Surface metric values were highly variable across the floodplain and revealed a high degree of spatial organisation in floodplain topography. Moran's I correlograms fit to the landscape of each metric at each window size revealed that patchiness existed at nearly all window sizes, but the strength and scale of patchiness changed within window size, suggesting that multiple scales of patchiness and patch structure exist in the topography of this floodplain. Scale thresholds in the spatial patterns were observed, particularly between the 50 and 100 m window sizes for all surface metrics and between the 500 and 750 m window sizes for most metrics. These threshold scales are ~ 15–20% and 150% of the main channel width (1–2% and 10–15% of the floodplain width), respectively. These thresholds may be related to structuring processes operating across distinct scale ranges. By coupling surface metrics, multi-scale analyses, and correlograms, quantifying floodplain topographic complexity is possible in ways that should assist in clarifying how floodplain ecosystems are structured.