Interaction Between Ecohydrologic Dynamics and Microtopographic Variability Under Climate Change
Interaction Between Ecohydrologic Dynamics and Microtopographic Variability Under Climate Change
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DOI：
10.1002/2017wr020377
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发表时间：
2017-10-01
影响因子：
5.4
通讯作者：
Kumar, Praveen
中科院分区：
文献类型：
--
作者：
Le, Phong V. V.;Kumar, Praveen
大气CO2浓度升高导致的植被适应，沿着对温度升高和降雨模式改变的响应，预计将导致生态和水文功能的紧急行为。我们假设，微地形的变化，这是典型的景观功能的长度尺度的顺序米，如地形凹陷，将发挥重要作用，通过改变水分的持久性和可变性，在确定这种动态。为了研究这些新兴的生态水文动力学，我们开发了一个建模框架，Dhara，它明确地结合了微地形变化对植被，水分和能量动态的控制。密集的计算需求，从这样一个建模框架，允许耦合的土壤-植被连续体的多层建模与3-D表面-地下流过程的解决使用混合CPU-GPU并行计算框架。这项研究是在美国伊利诺伊州中部，这是占主导地位的行播农业，主要是大豆（大豆）和玉米（玉米）的集约化管理的农业景观不同的气候变化情景。我们发现，CO2浓度的上升将减少蒸散，从而增加土壤水分和地表水积水的地形凹陷。然而，从较高的空气温度增加的大气需求克服了这种保守的行为，导致蒸散量的净增加，从而减少土壤水分储存和积水的持久性。这些结果揭示了气候变化下的植被驯化和微地形变异控制生态水文过程之间的联系。简单的语言摘要气候变化，其中包括大气CO2浓度和温度升高，正在改变植被的生理生态响应。较高的大气CO2对某些类型的植被具有保水作用，而温度的升高会导致更高的蒸散需求。因此，我们预计，这种相互作用的竞争效应将发挥微妙的方式，因此microtopographic可变性将发挥重要作用，在他们的动态。我们首次开发了建模功能，通过利用LiDAR数据来绘制这些微妙的动态。然而，这种建模是计算密集型的。本研究发展了一个混合并行计算框架，以解开植被和微地形变化的生态生理响应之间的相互作用，使用高分辨率建模。我们证明了我们的模型的适用性，以研究这种相互作用，在一个集中管理的景观在中西部，美国。结果表明，CO2浓度的升高会导致土壤蒸散量的减少，从而增加土壤含水量和地表水，增加洼地积水。然而，增加空气温度克服了这种保守的行为，导致蒸散量的净增加，从而减少土壤水分储存和持续积水。这项工作提高了我们对气候变化下生态水文系统变化的认识。
Vegetation acclimation resulting from elevated atmospheric CO2 concentration, along with response to increased temperature and altered rainfall pattern, is expected to result in emergent behavior in ecologic and hydrologic functions. We hypothesize that microtopographic variability, which are landscape features typically of the length scale of the order of meters, such as topographic depressions, will play an important role in determining this dynamics by altering the persistence and variability of moisture. To investigate these emergent ecohydrologic dynamics, we develop a modeling framework, Dhara, which explicitly incorporates the control of microtopographic variability on vegetation, moisture, and energy dynamics. The intensive computational demand from such a modeling framework that allows coupling of multilayer modeling of the soil-vegetation continuum with 3-D surface-subsurface flow processes is addressed using hybrid CPU-GPU parallel computing framework. The study is performed for different climate change scenarios for an intensively managed agricultural landscape in central Illinois, USA, which is dominated by row-crop agriculture, primarily soybean (Glycine max) and maize (Zea mays). We show that rising CO2 concentration will decrease evapotranspiration, thus increasing soil moisture and surface water ponding in topographic depressions. However, increased atmospheric demand from higher air temperature overcomes this conservative behavior resulting in a net increase of evapotranspiration, leading to reduction in both soil moisture storage and persistence of ponding. These results shed light on the linkage between vegetation acclimation under climate change and microtopography variability controls on ecohydrologic processes.Plain Language Summary Changes in climate, which include elevated atmospheric CO2 concentration and temperature, are altering ecophysiological responses of vegetation. Higher atmospheric CO2 has a water conservative effect on certain types of vegetation while increase in temperature drives higher evapotranspiration demand. We, therefore, expect that this interplay of competing effects will play out in subtle ways, and therefore microtopographic variability will play an important role in their dynamics. For the first time, we develop modeling capabilities to draw out these subtle dynamics by utilizing LiDAR data. However, such modeling is compute-intensive. This study develops a hybrid parallel computing framework to unravel the interaction between ecophysiological responses of vegetation and microtopographic variability using high-resolution modeling. We demonstrate the applicability of our model to study this interaction in an intensively managed landscape in the Midwest, USA. We find that rising CO2 concentration will decrease evapotranspiration, thus increasing soil moisture and surface water and ponding in topographic depressions. However, increased air temperature overcomes this conservative behavior resulting in a net increase of evapotranspiration, leading to reduction in soil moisture storage and persistence of ponding. This work improves our understanding of changes in ecohydrologic systems under climate change.