Examining Seasonal Trends in Sediment Source Contributions in an Intensely Cultivated Midwestern Sub-Watershed Using Bayesian Unmixing
Examining Seasonal Trends in Sediment Source Contributions in an Intensely Cultivated Midwestern Sub-Watershed Using Bayesian Unmixing
复制标题
使用贝叶斯分解检查集中耕种的中西部子流域沉积物源贡献的季节性趋势
DOI：
10.1061/9780784413548.146
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发表时间：
2014
影响因子：
3.2
通讯作者：
C. Wilson
中科院分区：
文献类型：
--
作者：
B. Abban;A. Papanicolaou;M. Cowles;C. Wilson
本研究旨在揭示一些在爱荷华州，美国南阿玛纳子流域（SASW），在季节尺度上的沉积物源贡献的动态。2007年4月至8月定期进行实地研究，从高地和溪流网络收集沉积物来源和侵蚀样品。通过质谱法获得样品的δ 13 C和δ 15 N特征，并将其用作“指纹”来识别不同的贡献源。对于未取样的源，采用该区域类似系统的δ 13 C和δ 15 N文献值。使用示踪剂签名的侵蚀样品的非混合实现了与现有的贝叶斯，马尔可夫链蒙特卡罗（MCMC）模型，结构，以及代表密集栽培SASW系统的增强版本。在沉积物源的贡献之间的平衡转移高地和流源的季节。这项研究的初步结果证实了其他研究的观察结果，即水文因素和沉积物的可利用性对高地和河流来源的相对贡献有重大影响。此外，研究表明，树冠覆盖与裸露的土壤起着重要的作用，应考虑到进行非混合研究，旨在确定沉积物来源。
This study aims to shed some light on the dynamics of sediment source contributions in the South Amana Sub-Watershed (SASW) in Iowa, USA, at a seasonal scale. Field studies were performed periodically from April to August 2007, in which sediment source and eroded samples were collected from the uplands and the stream network. The δ 13 C and δ 15 N signatures of the samples were obtained via mass spectrometry and used as “fingerprints” to identify the different contributing sources. For sources that were not sampled, literature values of δ 13 C and δ 15 N from similar systems in the region were adopted. Un-mixing of the eroded samples using the tracer signatures was achieved with an enhanced version of an existing Bayesian, Markov Chain Monte Carlo (MCMC) model, structured to well represent the intensely cultivated SASW system. Balance in sediment source contributions shifted between upland and in-streams sources over the season. Preliminary results from the study confirm observations from other studies that hydrological factors and sediment availability significantly affect the relative contributions of upland and in-stream sources. In addition, the study shows that canopy cover vs. bare soil plays an important role and should be taken into consideration when performing un-mixing studies designed to identify sediment sources.