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INTEGRATING modeling AND FIELD EXPERIMENTS TO EVALUATE IMPACTS OF VEGETATIVE PRACTICES ON PONDEROSA PINE WATERSHEDS

JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION 2008年第5期44卷 1284-1294页

作者： Lopes, Vicente L. Vogl, Adrian L. SW Texas State Univ Dept Biol San Marcos TX 78666 USA SW Texas State Univ Dept Biol San Marcos TX 78666 USA

Determining watershed response to vegetation treatment has been the subject of numerous hydrologic studies over the years. However, generalizing the information obtained from traditional paired-watershed studies to other watersheds in a region is problematic because of the empirical nature of such studies and the context dependence of hydrologic responses. This paper addresses the issue of generalizing hydrologic information through integration of process-based modeling and field observations from small-scale watershed experiments. To this end, the results from application of a process-based model were compared with the results from small-scale watershed experiments in ponderosa pine forests of Arizona. The model simulated treatment impacts reasonably well when compared to the traditional paired-watershed approach. However, the model tended to overestimate water yields during periods of low flow, and there was a significant difference between the two approaches in the estimation of treatment impacts during the first four years following treatment. The results indicate that the lumped-parameter modeling approach used here may be limited in its ability to detect small changes, and tends to overestimate changes that occur immediately following treatment. It is concluded that watershed experiments can be highly informative due to their direct examination of cause-effect relationships, while process-based models are useful for their processing power and focus on functional relationships. The integrated use of both watershed experiments and process-based models provides a way to generalize hydrologic information, illuminate the processes behind landscape treatment effects, and to generate and test hypotheses.

关键词： watershed experiments process-based modeling water balance vegetative practices sensitivity analysis parameter estimation model calibration BROOK90

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Effect of permafrost degradation on grassland net primary productivity in Qinghai-Tibet Plateau

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ENVIRONMENTAL RESEARCH LETTERS 2024年第10期19卷 104051-104051页

作者： Hu, Jianan Nan, Zhuotong Ji, Hailong Zhao, Shuping Ou, Minyue Nanjing Normal Univ Minist Educ Virtual Geog Environm Key Lab Nanjing 210023 Peoples R China Jiangsu Acad Agr Sci Wuxi Branch Wuxi 214174 Peoples R China Jiangsu Ctr Collaborat Innovat Geog Informat Resou Nanjing 210023 Peoples R China

Climate warming poses complex challenges for alpine ecosystems on the Qinghai-Tibetan Plateau (QTP), further exacerbated by permafrost degradation. Quantifying the specific ecological impacts of permafrost thaw remains elusive, as ecological variations are also influenced by external climate factors. This study tackles this gap by employing the Noah-MP model to simultaneously simulate permafrost thermal-hydrological dynamics and net primary production (NPP) across the Three River Headwaters Region from 1989 to 2018. Model results were validated against observations. To isolate the ecological effects of permafrost thaw, we implemented a novel relative time transformation on the simulation results. Our analysis reveals a 7.5 x 104 km2 reduction in permafrost coverage during the study period, coinciding with a 1.09 g C m-2 yr-2 increase in NPP. While precipitation is the primary driver of NPP changes in most years, soil moisture emerges as a crucial factor during permafrost disappearance, when the ground transitions to seasonally frozen ground. Surprisingly, the NPP response to permafrost disappearance exhibited a transient effect, diminishing to negligible levels within five years post-thaw. These findings enhance our understanding of the intricate and dynamic responses of the QTP ecosystem to permafrost degradation under a warming climate.

关键词： ecological resilience permafrost net primary production process-based modeling Qinghai-Tibet Plateau

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Will tree species experience increased frost damage due to climate change because of changes in leaf phenology?

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CANADIAN JOURNAL OF FOREST RESEARCH 2014年第12期44卷 1555-1565页

作者： Morin, Xavier Chuine, Isabelle Univ Montpellier 3 Univ Montpellier CNRS CEFEUMR 5175EPHEEquipe BIOFLUX F-34293 Montpellier 5 France

In temperate zones, trees tend to unfold their leaves earlier due to climate warming. However, changes in the timing of the bud development also affect the dynamics of the cold-hardening process, which may increase frost injuries endured by trees because new leaves unfold at a period when frost events can still occur. This possible increase in frost damage in response to climate change is known as the "frost-damage hypothesis". In this study, we have tested this hypothesis by forcing a process-based frost-injury model with process-based phenological models for 22 North American species with two Intergovernmental Panel on Climate Change storylines. Using a simplified parameterization of the frost-injury model, we found that risk of frost injury changed with climate change for all species. In fact, frost injury decreased for the vast majority of the species, but this trend varied across species and throughout each species' distribution. We further explored the variability of response among species using their phenological and geographic characteristics. The interspecific trends depicted here show what could be the implications of climate change on the ecophysiology of boreal and temperate trees and highlight the importance of process-based models in studying the complexity of long-term impacts of climate change on species biology.

关键词： climate change frost damage phenology process-based modeling geographical distribution comparative analysis trees North America

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COMPARISON OF RZWQM2 AND DNDC MODELS TO SIMULATE GREENHOUSE GAS EMISSIONS UNDER COMBINED INORGANIC/ORGANIC FERTILIZATION IN A SUBSURFACE-DRAINED FIELD

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TRANSACTIONS OF THE ASABE 2020年第4期63卷 771-787页

作者： Jiang, Q. Qi, Z. Madramootoo, C. A. Smith, W. Abbasi, N. A. Zhang, T. Q. McGill Univ Dept Bioresource Engn Ste Anne De Bellevue PQ Canada Agr & Agri Food Canada Ottawa Res & Dev Ctr Ottawa ON Canada Agr & Agri Food Canada Harrow Res & Dev Ctr Harrow ON Canada

N management has the potential to mitigate greenhouse gas (GHG) emissions. process-based models are promising tools for evaluating and developing management practices that may optimize sustainability goals as well as promote crop productivity. In this study, the GHG emission component of the Root Zone Water Quality Model (RZWQM2) was tested under two different types of N management and subsequently compared with the Denitrification-Decomposition (DNDC) model using measured data from a subsurface-drained field with a corn-soybean rotation in southern Ontario, Canada. Field-measured data included N2O and CO2 fluxes, soil temperature, and soil moisture content from a four-year field experiment (2012 to 2015). The experiment was composed of two N treatments: inorganic fertilizer (IF), and inorganic fertilizer combined with solid cattle manure (SCM). Both models were calibrated using the data from IF and validated with SCM. Statistical results indicated that both models predicted well the soil temperature, but RZWQM2 performed better than DNDC in simulating soil water content (SWC) because DNDC lacked a heterogeneous soil profile, had shallow simulation depth, and lacked crop root density functions. Both RZWQM2 and DNDC predicted the cumulative N2O and CO2 emissions within 15% error under all treatments, while the timing of daily CO2 emissions was more accurately predicted by RZWQM2 (RMSE = 0.43 to 0.54) than by DNDC (RMSE = 0.60 to 0.67). modeling results for N management effects on GHG emissions showed consistency with the field measurements, indicating higher CO2 emissions under SCM than IF, higher N2O emissions under IF in corn years, but lower N2O emissions in soybean years. Overall, RZWQM2 required more experienced and intensive calibration and validation, but it provided more accurate predictions of soil hydrology and better timing of CO2 emissions than DNDC.

关键词： CO2 emission Corn-soybean rotation Inorganic fertilization Manure application N2O emission process-based modeling

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Morphodynamic impacts of large-scale engineering projects in the Yangtze River delta

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COASTAL ENGINEERING 2018年第Nov.期141卷 1-11页

作者： Luan, Hua Long Ding, Ping Xing Wang, Zheng Bing Yang, Shi Lun Lu, Jin You Changjiang River Sci Res Inst Wuhan 430010 Hubei Peoples R China East China Normal Univ State Key Lab Estuarine & Coastal Res Shanghai 200062 Peoples R China Delft Univ Technol Fac Civil Engn & Geosci POB 5048 NL-2600 GA Delft Netherlands Deltares POB 177 NL-2600 MH Delft Netherlands

Morphodynamics of world's river deltas are increasingly affected by human activities, which are of great ecological, economic and social implications. However, impacts of human interventions in deltaic regions are insufficiently understood, especially superimposed upon diminishing sediment supplies. This study uses the heavily interfered Yangtze River delta as an example to address this issue. The morphodynamic impacts of the Deepwater Navigation Channel Project (DNCP) during 1997-2013 are investigated through process -based modeling approach (Delft3D) and bathymetric data analysis. The DNCP was implemented in the mouth bar area of the Yangtze River delta including the twin dikes and 19 groynes with the total length of 132.0 km. Hydrodynamic simulations indicate that the training walls resulted in weaker tidal flow and longer slack period at the East Hengsha Shoal (EHS) and stronger tidal flow at the subaqueous delta. Thus, the EHS is characterized as a sediment accumulation zone after the completion of the training walls. Subsequently, morphological modeling shows enhanced accretion at the EHS and enhanced erosion at the subaqueous delta when the training walls are taken into account. Numerical experiments further demonstrate that the above changes are mainly attributed to the seaward half of the northern training walls constructed in 2002-2005. This is probably the reason for the observed accretion peak of the EHS in 2002-2007 and the gradual increase in the erosion rate of the subaqueous delta after 2002. The schematized paths of sediment transport after the DNCP indicate that sediment eroded from the subaqueous delta serves as an important source for accretion of the mouth bar area. It is suggested that siltation promoting projects within the mouth bar area increased shallow shoal accretion and aggravated erosion at the subaqueous delta. With the overall erosion of the Yangtze River delta due to river sediment reduction, large-scale estuarine engineering project

关键词： Morphodynamics Estuarine engineering projects process-based modeling Yangtze river delta

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modeling state-level soil carbon emission factors under various scenarios for direct land use change associated with United States biofuel feedstock production

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BIOMASS & BIOENERGY 2013年 55卷 299-310页

作者： Kwon, Ho-Young Mueller, Steffen Dunn, Jennifer B. Wander, Michelle M. Univ Illinois Dept Nat Resources & Environm Sci Urbana IL 61801 USA Univ Illinois Energy Resources Ctr Chicago IL 60607 USA Argonne Natl Lab Ctr Transportat Res Argonne IL 60439 USA

Current estimates of life cycle greenhouse gas emissions of biofuels produced in the US can be improved by refining soil C emission factors (EF;C emissions per land area per year) for direct land use change associated with different biofuel feedstock scenarios. We developed a modeling framework to estimate these EFs at the state-level by utilizing remote sensing data, national statistics databases, and a surrogate model for CENTURY's soil organic C dynamics submodel (SCSOC). We estimated the forward change in soil C concentration within the 0-30 cm depth and computed the associated EFs for the 2011 to 2040 period for croplands, grasslands or pasture/hay, croplands/conservation reserve, and forests that were suited to produce any of four possible biofuel feedstock systems [corn (Zea Mays L)-corn, corn-corn with stover harvest, switchgrass (Panicum virgatum L), and miscanthus (Miscanthus x giganteus Greef et Deuter)]. Our results predict smaller losses or even modest gains in sequestration for corn based systems, particularly on existing croplands, than previous efforts and support assertions that production of perennial grasses will lead to negative emissions in most situations and that conversion of forest or established grasslands to biofuel production would likely produce net emissions. The proposed framework and use of the SCSOC provide transparency and relative simplicity that permit users to easily modify model inputs to inform biofuel feedstock production targets set forth by policy. (C) 2013 Elsevier Ltd. All rights reserved.

关键词： Soil C emissions factors Direct land use change United States biofuel feedstock production process-based modeling Surrogate CENTURY soil organic C model

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Equation Discovery for Nonlinear System Identification

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IEEE ACCESS 2020年 8卷 29930-29943页

作者： Simidjievski, Nikola Todorovski, Ljupco Kocijan, Jus Dzeroski, Saso Jozef Stefan Inst Ljubljana 1000 Slovenia Univ Cambridge Dept Comp Sci & Technol Cambridge CB3 0FD England Univ Ljubljana Fac Publ Adm Ljubljana 1000 Slovenia Univ Nova Gorica Sch Engn & Management Nova Gorica 5000 Slovenia Jozef Stefan Int Postgrad Sch Ljubljana 1000 Slovenia

Equation discovery methods enable modelers to combine domain-specific knowledge and system identification to construct models most suitable for a selected modeling task. The method described and evaluated in this paper can be used as a nonlinear system identification method for gray-box modeling. It consists of two interlaced parts of modeling that are computer-aided. The first performs computer-aided identification of a model structure composed of elements selected from user-specified domain-specific modeling knowledge, while the second part performs parameter estimation. In this paper, recent developments of the equation discovery method called process-based modeling, suited for nonlinear system identification, are elaborated and illustrated in two continuous-time case studies. The first case study illustrates the use of the process-based modeling on synthetic data while the second case-study evaluates process-based modeling on measured data for a standard system-identification benchmark. The experimental results clearly demonstrate the ability of process-based modeling to reconstruct both model structure and parameters from measured data.

关键词： Machine learning nonlinear system identification equation discovery process-based modeling computational scientific discovery knowledge-based identification

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Quantifying the effects of climate change and harvesting on carbon dynamics of boreal aspen and jack pine forests using the TRIPLEX-Management model

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FOREST ECOLOGY AND MANAGEMENT 2012年 281卷 152-162页

作者： Wang, Weifeng Peng, Changhui Kneeshaw, Daniel D. Larocque, Guy R. Song, Xinzhang Zhou, Xiaolu Univ Quebec Inst Sci Environm Succ Ctr Ville Montreal PQ H3C 3P8 Canada Univ Quebec Ctr Etud Foret Succ Ctr Ville Montreal PQ H3C 3P8 Canada Nat Resources Canada Laurentian Forestry Ctr Canadian Forest Serv Quebec City PQ G1V 4C7 Canada Zhejiang Agr & Forestry Univ Nurturing Stn State Key Lab Subtrop Silviculture Linan 311300 Zhejiang Peoples R China Zhejiang Agr & Forestry Univ Zhejiang Prov Key Lab Carbon Cycling & Carbon Seq Linan 311300 Zhejiang Peoples R China

A model that accurately evaluates changes in forest productivity and carbon (C) stocks in response to climate change and forest management will permit us to assess the impact of global changes. The goal of this study is to forecast potential effects of climate change and clearcuts on C dynamics of boreal trembling aspen (Populus tremuloides Michx.) and jack pine (Pinus banksiana Lamb.) forests near the southern edge of the boreal forest in Saskatchewan, Canada. We validated the TRIPLEX-Management model against eddy covariance measurements, C stocks, and growth data. Constant climate (repeated measurements) and four climate change scenarios (IPCC SRES A2 and B1) generated from Coupled Global Climate Model (CGCM3.1) and the Model for Interdisciplinary Research on Climate (MIROC3.2), respectively, were used in scenario simulations. Clearcuts were assumed to occur in 2010 and 2055 for each forest type. Normalized root mean square error (NRMSE) between simulated and observed variables including C fluxes, C stocks (e.g., aboveground biomass C and soil organic C), and stand characteristics such as mean DBH (diameter at breast height) and stand density ranged from 11% to 22%. The Willmott index of agreement (d) between simulated and observed variables ranged from 0.95 to 1.00 with the exception of net ecosystem productivity (NEP, d = 0.88). The model tended to project higher NEP and C stocks under warm but wet climate (CGCM3.1 A2 and B1) vs. warm and dry climate (MIROC3.2 A2 and B1), and slightly higher NEP under IPCC SERS B1 vs. A2, for both forest types. When clearcuts occurred, the model projected negative NEP (C losses) during the seven to 11 years following clearcuts for both forest types under the five climate scenarios. Regrowth of the forest generally led to greater C accumulation when clearcuts occurred in 2010 than in 2055. Overall, the TRIPLEX-Management model is capable of simulating C dynamics for aspen and jack pine forests as well as their responses to drough

关键词： Clearcut logging process-based modeling Rotation length Scenario analysis Soil organic carbon

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Exploratory morphodynamic hindcast of the evolution of the abandoned Yellow River delta, 1578-1855 CE

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MARINE GEOLOGY 2017年 383卷 99-119页

作者： Su, Min Yao, Peng Wang, Zheng Bing Zhang, Chang Kuan Stive, Marcel J. F. Sun Yat Sen Univ Sch Marine Sci Inst Estuarine & Coastal Res 135 Xingang Xi Rd Guangzhou 510275 Guangdong Peoples R China Delft Univ Technol Dept Hydraul Engn Fac Civil Engn & Geosci POB 5048 NL-2600 GA Delft Netherlands Guangdong Prov Key Lab Marine Resources & Coastal Guangzhou 510275 Guangdong Peoples R China Deltares Marine & Coastal Syst POB 177 NL-2600 MH Delft Netherlands Hohai Univ Coll Harbor Coastal & Offshore Engn 1st XiKang Rd Nanjing 210098 Jiangsu Peoples R China

The abandoned Yellow River delta (AYD), which formed when the Yellow River flowed into the Southern Yellow Sea between 1128 and 1855 CE, is a representative example of the sensitivity of deltas to modifications in their environments. In this study, we established a process-based morphodynamic model to explore the morphological evolution of one such large-scale fine-grained delta (the AYD before 1855 CE). The uncertainties in the model settings, which are inevitable when historical data are insufficient, were assessed together with the corresponding influences on the evolution of the deltaic system by considering a series of scenarios. The results indicate that the strength. of local tidal forcing is the key factor that determines the shape and evolutionary trend of the delta. Sediment input discharge and the slope of the initial coastal profile have a considerable effect on the overall size of the delta and the relative ratio between subaerial and subaqueous parts of the delta, respectively. based on the evaluation of the uncertainties and a comparison with historical maps, the simulated AYD was evaluated to be reliable. Through an analysis of the temporal delta evolution and residual sediment transport, the morphological evolution of the AYD before 1855 CE was investigated. The southern delta grew as the shoals merged with the mainland, which is in agreement with an existing hypothesis (Zhang, 1984), whereas the accretion of the northern delta was independent from the shoals in the northern part. Additionally, suggestions are made regarding the distribution of the AYD at the end of its progradation stage, which provides fundamental information for analyzing subsequent erosion processes since 1855 CE. This study differs from existing studies on the AYD, which are all based on geological approaches. It provides insight into the evolution of the AYD through an alternative means, viz. a process-based morphodynamic-modeling approach. (C) 2016 Elsevier B.V. All rights re

关键词： Abandoned Yellow River delta Morphodynamics process-based modeling Uncertainty Historical maps

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SURFWET: A biokinetic model for surface flow constructed wetlands

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SCIENCE OF THE TOTAL ENVIRONMENT 2020年 723卷 137650-137650页

作者： Aragones, David G. Sanchez-Ramos, David Calvo, Gabriel F. Univ Castilla La Mancha Sch Civil Engn Dept Math Av Camilo Jose Cela S-N Ciudad Real 13071 Spain Univ Castilla La Mancha Sch Civil Engn Res Grp Hydroecol Av Camilo Jose Cela S-N Ciudad Real 13071 Spain

Constructed wetlands are an alternative biotechnology for wastewater treatment that have several advantages over conventional systems. In this work, a biokinetic model for surface flow constructed wetlands is presented (SURFWET). SURFWET belongs to a class of models that are not only interesting from a theoretical viewpoint, as they allow to improve the understanding of the underlying processes;but also from a practical viewpoint, because they can be useful for optimal designs of constructed wetlands, complementing current empirical methods. The proposed model is centered on the intervening physical and biochemical processes involved in pollutant removal in wastewater (organic matter, nitrogen, phosphorus, suspended solids), capturing the interplay of the main agents on contaminant removal (bacteria, macrophytes and phytoplankton). Furthermore, the hydraulic model considers water volume as a variable depending on the outlet hydraulic capacity, and dissolved oxygen has also been introduced as a key driver of reaction kinetics of wetlands. Beyond putting forward a theoretical framework, SURFWET has been applied to simulate a specific case to demonstrate its robustness, in a 12-year-interval simulation. The results show the typical seasonality of this biotechnology, highlighting the importance of dissolved oxygen, which is a key limiting factor on a large number of biochemical processes. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Treatment wetlands Free-water surface process-based modeling Wastewater Pollutant removal Mathematical model

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