Upscaling key ecosystem functions across the conterminous United States by a water‐centric ecosystem model
Upscaling key ecosystem functions across the conterminous United States by a water‐centric ecosystem model
复制标题
DOI：
10.1029/2010jg001573
复制
发表时间：
2011-09
影响因子：
--
通讯作者：
G. Sun;P. Caldwell;A. Noormets;S. McNulty;E. Cohen;J. M. Myers;J. Domec;E. Treasure;Q. Mu
中科院分区：
文献类型：
--
作者：
G. Sun;P. Caldwell;A. Noormets;S. McNulty;E. Cohen;J. M. Myers;J. Domec;E. Treasure;Q. Mu
[1]我们开发了一个以水为中心的月尺度模拟模型（WaSSI-C），通过整合FLUXNET网络和现有的水资源供需核算模型（WaSSI）的经验水和碳通量测量。2001年至2006年，在美国接壤的2103个8位水文单位代码流域，通过多种独立方法对流域尺度蒸散量（ET）、总生态系统生产力（GEP）和净生态系统交换（NEE）进行了评估。我们的研究结果表明，WaSSI-C捕获的空间和时间的变化和大干旱对关键生态系统通量的影响。我们模拟的平均（±空间标准差）ET（556 ± 228 mm yr−1）与基于中分辨率成像光谱仪（MODIS）的ET（527 ± 251 mm yr−1）和基于流域水平衡的ET（571 ± 242 mm yr−1）进行了很好的比较。我们的年平均GEP估计值（1362 ± 688 g C m−2 yr−1）与基于涡动通量的EC-MOD模型的估计值（1194 ± 649 g C m−2 yr−1）相比（R2 = 0.83）很好，但两种方法都比标准MODIS产品（904 ± 467 g C m−2 yr−1）高出25-30%。在18个水资源区中，东南部的产水量和固碳能力最高。当考虑所有生态系统时，本研究预测的平均NEE（−353 ± 298 g C m−2 yr−1）比EC-MOD的估计值（−220 ± 225 g C m−2 yr−1）高60%，这表明在大尺度上量化NEE的总体不确定性很高。我们的水为中心的模型提供了一个新的工具，在不断变化的环境下，检查区域水和碳资源之间的权衡。
[1] We developed a water-centric monthly scale simulation model (WaSSI-C) by integrating empirical water and carbon flux measurements from the FLUXNET network and an existing water supply and demand accounting model (WaSSI). The WaSSI-C model was evaluated with basin-scale evapotranspiration (ET), gross ecosystem productivity (GEP), and net ecosystem exchange (NEE) estimates by multiple independent methods across 2103 eight-digit Hydrologic Unit Code watersheds in the conterminous United States from 2001 to 2006. Our results indicate that WaSSI-C captured the spatial and temporal variability and the effects of large droughts on key ecosystem fluxes. Our modeled mean (±standard deviation in space) ET (556 ± 228 mm yr−1) compared well to Moderate Resolution Imaging Spectroradiometer (MODIS) based (527 ± 251 mm yr−1) and watershed water balance based ET (571 ± 242 mm yr−1). Our mean annual GEP estimates (1362 ± 688 g C m−2 yr−1) compared well (R2 = 0.83) to estimates (1194 ± 649 g C m−2 yr−1) by eddy flux-based EC-MOD model, but both methods led significantly higher (25–30%) values than the standard MODIS product (904 ± 467 g C m−2 yr−1). Among the 18 water resource regions, the southeast ranked the highest in terms of its water yield and carbon sequestration capacity. When all ecosystems were considered, the mean NEE (−353 ± 298 g C m−2 yr−1) predicted by this study was 60% higher than EC-MOD's estimate (−220 ± 225 g C m−2 yr−1) in absolute magnitude, suggesting overall high uncertainty in quantifying NEE at a large scale. Our water-centric model offers a new tool for examining the trade-offs between regional water and carbon resources under a changing environment.