Exploring the Effect of Aspect to Inform Future Earthcasts of Climate‐Driven Changes in Weathering of Shale
Exploring the Effect of Aspect to Inform Future Earthcasts of Climate‐Driven Changes in Weathering of Shale
复制标题
探索方位的影响，以了解气候驱动的页岩风化变化的未来地球预报
DOI：
10.1029/2017jf004556
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Brantley, S. L.
中科院分区：
文献类型：
--
作者：
Sullivan, P. L.;Goddéris, Y.;Shi, Y.;Gu, X.;Schott, J.;Hasenmueller, E. A.;Kaye, J.;Duffy, C.;Jin, L.;Brantley, S. L.
对临界区内未来条件的预测--地球预报--可以用来了解气候变化对影响地貌的过程的潜在影响。我们正在开发一种方法，利用气候变化的情景来预测未来风化作用将如何变化。作为第一步，我们在一个研究得很好的东西向分水岭(美国宾夕法尼亚州页岩山)的山坡上，使用土方法模拟与坡向有关的土壤水化学和风化的影响。我们完成了土壤水中溶质化学的模型模拟，并将其与流域观测结果进行了比较。在考虑坡向的情况下，集水区阳光侧的水分风化通量较高。但坡向对温度(阳面较暖的土壤0.8℃)和补给量(阴面大于100 mm/年)的单独影响不能解释阳面观测到的较高风化通量的大小。模拟的风化通量与坡向相关的差异只有在我们结合了在两个山坡上的加筋土壤中观察到的粘土含量的测量差异时才接近现场观察。我们还必须包括一个生物提升模块，以准确描述土壤水中阳离子浓度随深度的变化。生物抬升降低了部分矿物的溶解速率，但加速了高岭石的沉淀。这些短期模拟还强调，流域两侧颗粒大小的遗传差异本身可能是由于不同小气候下的风化作用造成的--持续时间比我们的模型模拟的更长。
Projections of future conditions within the critical zone—earthcasts—can be used to understand the potential effects of changes in climate on processes affecting landscapes. We are developing an approach to earthcast how weathering will change in the future using scenarios of climate change. As a first step here, we use the earthcasting approach to model aspect‐related effects on soil water chemistry and weathering on hillsides in a well‐studied east‐west trending watershed (Shale Hills, Pennsylvania, USA). We completed model simulations of solute chemistry in soil water with and without the effect of aspect for comparison to catchment observations. With aspect included, aqueous weathering fluxes were higher on the sunny side of the catchment. But the effect of aspect on temperature (0.8 °C warmer soil on sunny side) and recharge (100 mm/year larger on shaded side) alone did not explain the magnitude of the observed higher weathering fluxes on the sunny side. Modeled aspect‐related differences in weathering fluxes only approach field observations when we incorporated the measured differences in clay content observed in augered soils on the two hillslopes. We also had to include a biolifting module to accurately describe cation concentrations in soil water versus depth. Biolifting lowered some mineral dissolution rates while accelerating kaolinite precipitation. These short‐duration simulations also highlighted that the inherited differences in particle size on the two sides of the catchment might in themselves be explained by weathering under different microclimates caused by aspect—over longer durations than simulated with our models.