检索结果-内蒙古大学图书馆

modeling tidal sand wave recovery after dredging:effect of different types of dredging strategies

COASTAL ENGINEERING 2021年 165卷 103862-103862页

作者： Campmans, G. H. P. Roos, P. C. Van der Sleen, N. R. Hulscher, S. J. M. H. Water Engn & Management POB 217 NL-7500 AE Enschede Netherlands Rijkswaterstaat Water Verkeer & Leefomgeving Utrecht Netherlands

Maintenance of navigation channels in shelf seas with tidal sand waves usually requires repeated dredging operations. Optimizing these interventions is a difficult task, particularly complicated by the nonlinear morphodynamics of sand wave recovery after dredging. Here we present a process-based model study, incorporating different strategies of dredging in an existing nonlinear sand wave model. We consider 'topping' (removing sand from crest) and 'swiping' (same, but now placing it in the troughs), for a range of dredging depths. Starting point is a fully developed sand wave or sand wave field, as simulated in the model. Results indicate that sand wave recovery is slowest after swiping. Also, larger dredging volumes imply longer recovery times. Next, we study the maintenance intervals and (cumulative) dredging volumes resulting from adopting a typical temporal strategy: swipe to a prescribed dredging depth, as soon as the recovering sand wave crests have reached a critical depth. Maintenance intervals are found to depend on the dredging depth and, importantly, to vary over time, as well. This last result shows that sand wave recovery depends not only on height, but also on its shape, emphasizing the limitations of existing, empirical (Landau-type of) models based on amplitude (or height) only.

关键词： Tidal sand waves Dredging strategies Morphodynamics process-based modeling

来源：评论

学校读者我要写书评

暂无评论

Underestimation of the Tambora effects in North American taiga ecosystems

引用

ENVIRONMENTAL RESEARCH LETTERS 2018年第3期13卷 034017-034017页

作者： Gennaretti, Fabio Boucher, Etienne Nicault, Antoine Gea-Izquierdo, Guillermo Arseneault, Dominique Berninger, Frank Savard, Martine M. Begin, Christian Guiot, Joel Aix Marseille Univ CNRS IRD Coll FranceCEREGE F-13545 Aix En Provence France Univ Lorraine AgroParisTech INRA UMR1434 F-54000 Nancy France Univ Quebec Montreal Dept Geog Montreal PQ H3C 3P8 Canada Univ Quebec Montreal Geotop Montreal PQ H3C 3P8 Canada Aix Marseille Univ CNRS ECCOREV F-13545 Aix En Provence France INIA CIFOR Dept Sistemas & Recursos Forest Madrid 28040 Spain Univ Quebec Rimouski Dept Biol Chim & Geog Rimouski PQ G5L 3A1 Canada Univ Helsinki Dept Forest Sci Helsinki 00014 Finland Nat Resources Canada Geol Survey Canada Quebec City PQ G1K9A9 Canada

The Tambora eruption (1815 AD) was one of the major eruptions of the last two millennia and has no equivalents over the last two centuries. Here, we collected an extensive network of early meteorological time series, climate simulation data and numerous, well-replicated proxy records from Eastern Canada to analyze the strength and the persistence of the Tambora impact on the regional climate and forest processes. Our results show that the Tambora impacts on the terrestrial biosphere were stronger than previously thought, and not only affected tree growth and carbon uptake for a longer period than registered in the regional climate, but also determined forest demography and structure. Increased tree mortality, four times higher than the background level, indicates that the Tambora climatic impact propagated to influence the structure of the North American taiga for several decades. We also show that the Tambora signal is more persistent in observed data (temperature, river ice dynamics, forest growth, tree mortality) than in simulated ones (climate and forest-growth simulations), indicating that our understanding of the mechanisms amplifying volcanic perturbations on climates and ecosystems is still limited, notably in the North American taiga.

关键词： tambora legacy Eastern Canada regional climate responses terrestrial biosphere responses forest demography mechanistic understanding process-based modeling

来源：评论

学校读者我要写书评

暂无评论

Elucidating controls on cyanobacteria bloom timing and intensity via Bayesian mechanistic modeling

引用

SCIENCE OF THE TOTAL ENVIRONMENT 2021年第Part1期755卷 142487-142487页

作者： Del Giudice, Dario Fang, Shiqi Scavia, Donald Davis, Timothy W. Evans, Mary Anne Obenour, Daniel R. NC State Univ Dept Civil Construct & Environm Engn Raleigh NC 27695 USA Univ Michigan Sch Environm & Sustainabil Ann Arbor MI 48104 USA Bowling Green State Univ Dept Biol Sci Bowling Green OH 43403 USA US Geol Survey Great Lakes Sci Ctr Ann Arbor MI 48105 USA NC State Univ Ctr Geospatial Analyt Raleigh NC 27695 USA

The adverse impacts of harmful algal blooms (HABs) are increasing worldwide. Lake Erie is a North American Great Lake highly affected by cultural eutrophication and summer cyanobacterial HABs. While phosphorus loading is a known driver of bloom size, more nuanced yet crucial questions remain. For example, it is unclear what mechanisms are primarily responsible for initiating cyanobacterial dominance and subsequent biomass accumulation. To address these questions, we develop a mechanistic model describing June-October dynamics of chlorophyll a, nitrogen, and phosphorus near the Maumee River outlet, where blooms typically initiate and are most severe. We calibrate the model to a new, geostatistically-derived dataset of daily water quality spanning 2008-2017. A Bayesian framework enables us to embed prior knowledge on system characteristics and test alternative model formulations. Overall, the best model formulation explains 42% of the variability in chlorophyll a and 83% of nitrogen, and better captures bloom timing than previous models. Our results, supported by cross validation, show that onset of the major midsummer bloom is associated with about a month of water temperatures above 20 degrees C (occurring 19 July to 6 August), consistent with when cyanobacteria dominance is usually reported. Decreased phytoplankton loss rate is the main factor enabling biomass accumulation, consistent with reduced zooplankton grazing on cyanobacteria. The model also shows that phosphorus limitation is most severe in August, and nitrogen limitation tends to occur in early autumn. Our results highlight the role of temperature in regulating bloom initiation and subsequent loss rates, and suggest that a 2 degrees C increase could lead to blooms that start about 10 days earlier and grow 23% more intense. (C) 2020 The US Geological Survey and Elsevier B.V. All rights reserved.

关键词： Eutrophication Harmful algal blooms Bayesian inference process-based modeling Great Lakes Hindcasts and projections

来源：评论

学校读者我要写书评

暂无评论

Reservoir water quality deterioration due to deforestation emphasizes the indirect effects of global change

引用

WATER RESEARCH 2022年 221卷 118721页

作者： Kong, Xiangzhen Ghaffar, Salman Determann, Maria Friese, Kurt Jomaa, Seifeddine Mi, Chenxi Shatwell, Tom Rinke, Karsten Rode, Michael Chinese Acad Sci Nanjing Inst Geog & Limnol State Key Lab Lake Sci & Environm Nanjing Peoples R China UFZ Helmholtz Ctr Environm Res Dept Lake Res Magdeburg Germany UFZ Helmholtz Ctr Environm Res Dept Aquat Ecosyst Anal & Management Magdeburg Germany Tech Univ Carolo Wilhelmina Braunschweig Leichtweiss Inst Hydraul Engn & Water Resources Braunschweig Germany Univ Potsdam Inst Environm Sci & Geog Potsdam Germany

Deforestation is currently a widespread phenomenon and a growing environmental concern in the era of rapid climate change. In temperate regions, it is challenging to quantify the impacts of deforestation on the catchment dynamics and downstream aquatic ecosystems such as reservoirs and disentangle these from direct climate change impacts, let alone project future changes to inform management. Here, we tackled this issue by investigating a unique catchment-reservoir system with two reservoirs in distinct trophic states (meso- and eutrophic), both of which drain into the largest drinking water reservoir in Germany. Due to the prolonged droughts in 2015-2018, the catchment of the mesotrophic reservoir lost an unprecedented area of forest (exponential increase since 2015 and ca. 17.1% loss in 2020 alone). We coupled catchment nutrient exports (HYPE) and reservoir ecosystem dynamics (GOTM-WET) models using a process-based modeling approach. The coupled model was validated with datasets spanning periods of rapid deforestation, which makes our future projections highly robust. Results show that in a short-term time scale (by 2035), increasing nutrient flux from the catchment due to vast deforestation (80% loss) can turn the mesotrophic reservoir into a eutrophic state as its counterpart. Our results emphasize the more prominent impacts of deforestation than the direct impact of climate warming in impairment of water quality and ecological services to downstream aquatic ecosystems. Therefore, we propose to evaluate the impact of climate change on temperate reservoirs by incorporating a time scale-dependent context, highlighting the indirect impact of deforestation in the short-term scale. In the long-term scale (e.g. to 2100), a guiding hypothesis for future research may be that indirect effects (e.g., as mediated by catchment dynamics) are as important as the direct effects of climate warming on aquatic ecosystems.

关键词： Deforestation Climate change Temperate regions Reservoir Eutrophication process-based modeling

来源：评论

学校读者我要写书评

暂无评论

Design and Simulation of Stormwater Control Measures Using Automated modeling

引用

WATER 2021年第16期13卷 2268页

作者： Radinja, Matej Skerjanec, Mateja Dzeroski, Saso Todorovski, Ljupco Atanasova, Natasa Univ Ljubljana Fac Civil & Geodet Engn Ljubljana 1000 Slovenia Jozef Stefan Inst Dept Knowledge Technol Ljubljana 1000 Slovenia Univ Ljubljana Fac Publ Adm Ljubljana 1000 Slovenia

Stormwater control measures (SCMs) are decentralized technical elements, which can prevent the negative effects of uncontrolled stormwater flow while providing co-benefits. Optimal SCMs have to be selected and designed to achieve the desired hydrological response of an urban catchment. In this study, automated modeling and domain-specific knowledge in the fields of modeling rainfall-runoff (RR) and SCMs are applied to automate the process of optimal SCM design. A new knowledge library for modeling RR and SCMs, compliant with the equation discovery tool ProBMoT (process-based modeling Tool), was developed. The proposed approach was used to (a) find the optimal RR model that best fits the available pipe flow measurements, and (b) to find the optimal SCMs design that best fits the target catchment outflow. The approach was applied to an urban catchment in the city of Ljubljana, Slovenia. First, nine RR models were created that generally had >> very good << performance according to the Nash-Sutcliffe efficiency criteria. Second, six SCM scenarios (i.e., detention pond, storage tank, bio-retention cell, infiltration trench, rain garden, and green roof) were automatically designed and simulated, enabling the assessment of their ability to achieve the target outflow. The proposed approach enables the effective automation of two complex calibration tasks in the field of urban drainage.

关键词： stormwater control measures rainfall-runoff model automated modeling domain knowledge equation discovery process-based modeling

来源：评论

学校读者我要写书评

暂无评论

modeling Intra- and Interannual Variability of BVOC Emissions From Maize, Oil-Seed Rape, and Ryegrass

引用

JOURNAL OF ADVANCES IN modeling EARTH SYSTEMS 2022年第3期14卷

作者： Havermann, Felix Ghirardo, Andrea Schnitzler, Joerg-Peter Nendel, Claas Hoffmann, Mathias Kraus, David Grote, Ruediger Karlsruhe Inst Technol Inst Meterol & Climate Res Atmospher Environm Res Garmisch Partenkirchen Germany Ludwig Maximilians Univ Munchen Dept Geog Munich Germany Leibniz Ctr Agr Landscape Res ZALF Muncheberg Germany Helmholtz Zentrum Munchen Res Unit Environm Simulat EUS Inst Biochem Plant Neuherberg Germany Univ Potsdam Inst Biochem & Biol Potsdam Germany Czech Acad Sci Global Change Res Inst Brno Czech Republic

Air chemistry is affected by the emission of biogenic volatile organic compounds (BVOCs), which originate from almost all plants in varying qualities and quantities. They also vary widely among different crops, an aspect that has been largely neglected in emission inventories. In particular, bioenergy-related species can emit mixtures of highly reactive compounds that have received little attention so far. For such species, long-term field observations of BVOC exchange from relevant crops covering different phenological phases are scarcely available. Therefore, we measured and modeled the emission of three prominent European bioenergy crops (maize, ryegrass, and oil-seed rape) for full rotations in north-eastern Germany. Using a proton transfer reaction-mass spectrometer combined with automatically moving large canopy chambers, we were able to quantify the characteristic seasonal BVOC flux dynamics of each crop species. The measured BVOC fluxes were used to parameterize and evaluate the BVOC emission module (JJv) of the physiology-oriented LandscapeDNDC model, which was enhanced to cover de novo emissions as well as those from plant storage pools. Parameters are defined for each compound individually. The model is used for simulating total compound-specific reactivity over several years and also to evaluate the importance of these emissions for air chemistry. We can demonstrate substantial differences between the investigated crops with oil-seed rape having 37-fold higher total annual emissions than maize. However, due to a higher chemical reactivity of the emitted blend in maize, potential impacts on atmospheric OH-chemistry are only 6-fold higher.

关键词： biogenic volatile organic compounds process-based modeling Zea mays Brassica napus Lolium multiflorum plant ontogenetic stage

来源：评论

学校读者我要写书评

暂无评论

Combinatorial search for selecting the structure of models of dynamical systems with equation discovery

引用

ENGINEERING APPLICATIONS OF ARTIFICIAL INTELLIGENCE 2020年第0期89卷 103423-000页

作者： Tanevski, Jovan Todorovski, Ljupco Dzeroski, Saso Jozef Stefan Inst Dept Knowledge Technol Ljubljana Slovenia Univ Ljubljana Fac Publ Adm Ljubljana Slovenia

Automated modeling aims at the induction of mathematical models, both their structure and parameter values, from time-series measurements of observed system variables. In this paper, we address the task of model structure selection, i.e., selecting an optimal structure from a user-specified finite set of alternative model structures, using various approaches to combinatorial search. We propose a mapping of the set of candidate model structures to a fixed-length, vector representation allowing the use of an arbitrary search algorithm as a solver of the structure selection task. We perform a comparative analysis of the performance of thirteen variants of several search algorithms, ranging from ones with high intensification, i.e., focus on neighborhood of the best candidate solutions, to ones with high diversification, i.e., focus on covering the entire search space. The empirical analysis involves eight tasks of reconstructing known models of dynamical systems from synthetic and measured data. The results of the analysis show that search algorithms involving moderate diversification methods have superior performance on the structure selection task. The empirical analysis also reveals that this finding is related to specific properties of the search space of candidate model structures.

关键词： Combinatorial optimization Combinatorial search Computational scientific discovery Equation discovery Symbolic regression Knowledge representation process-based modeling Dynamical systems

来源：评论

学校读者我要写书评

暂无评论

Monitoring and modeling dispersal of a submerged nearshore berm at the mouth of the Columbia River, USA

引用

COASTAL ENGINEERING 2023年 181卷

作者： Stevens, Andrew W. Moritz, Hans R. Elias, Edwin P. L. Gelfenbaum, Guy R. Ruggiero, Peter R. Pearson, Stuart G. McMillan, James M. Kaminsky, George M. US Geol Survey Pacific Coastal & Marine Sci Ctr 2885 Mission St Santa Cruz CA 95060 USA US Army Corps Engineers 333 SW First Ave Portland OR 97204 USA Deltares POB 177 NL-2600 MH Delft Netherlands Oregon State Univ Coll Earth Ocean & Atmospher Sci 2651 SW Orchard Ave Corvallis OR 97331 USA Delft Univ Technol Fac Civil Engn & Geosci POB 5048 NL-2600 GA Delft Netherlands Washington State Dept Ecol Coastal Monitoring & Anal Program POB 47600 Olympia WA 98504 USA

A submerged, low-relief nearshore berm was constructed in the Pacific Ocean near the mouth of the Columbia River, USA, using 216,000 m3 of sediment dredged from the adjacent navigation channel. The material dredged from the navigation channel was placed on the northern flank of the ebb-tidal delta in water depths between 12 and 15 m and created a distinct feature that could be tracked over time. Field measurements and numerical modeling were used to evaluate the transport pathways, time scales, and physical processes responsible for dispersal of the berm and evaluate the suitability of the location for operational placement of dredged material to enhance the sediment supply to eroding beaches onshore of the placement site. Repeated multibeam bathymetric surveys characterized the initial berm morphology and dispersion of the berm between September 22, 2020, and March 10, 2021. During this time, the volume of sediment within the berm decreased by about 40%to 127,000 m3, the maximum height decreased by almost 60%, and the center of the deposit shifted onshore over 200 m. Observations of berm morphology were compared with predictions from a three-dimensional hydrodynamic and sediment transport model application to refine poorly constrained model input parameters including sediment transport coefficients, bed schematization, and grain size. The calibrated sediment transport model was used to predict the amount, timing, and direction of transport outside of the observed survey area. Model simulations predicted that tidal currents were weak in the vicinity of the berm and wave processes including enhanced bottom stresses and asymmetric bottom orbital velocities resulted in dominant onshore movement of sediment from the berm toward the coastline. Roughly 50% of the berm volume was predicted to disperse away from the initial placement site during the 169 day hindcast. Between 9 and 17% of the initial volume of the berm was predicted to accumulate along the shoreface of a sho

关键词： Nearshore berm process-based modeling Delft3D Sediment transport

来源：评论

学校读者我要写书评

暂无评论

Amount of carbon fixed, transit time and fate of harvested wood products define the climate change mitigation potential of boreal forest management-A model analysis

引用

ECOLOGICAL MODELLING 2024年 491卷

作者： Metzler, Holger Launiainen, Samuli Vico, Giulia Swedish Univ Agr Sci SLU Dept Crop Prod Ecol POB 7043 S-75007 Uppsala Sweden Nat Resources Inst Latokartanonkaari 9 Helsinki 00790 Finland Swedish Univ Agr Sci SLU Dept Forest Ecol & Management Skogsmarksgrand 17 S-90183 Umea Sweden

Boreal forests are often managed to maximize wood production, but other goals, among which climate change mitigation, are increasingly important. Hence, it is necessary to examine synergies and trade-offs between forest production and its potential for carbon sequestration and climate change mitigation in forest stands. To this aim, we develop a novel mass -balanced process -based compartmental model that allows following the carbon path from its photosynthetic fixation until its return to the atmosphere by autotrophic or heterotrophic respiration, or by being burnt as wood product. Following carbon in the system allows to account for how long forest ecosystems and wood products retain carbon away from the atmosphere (i.e., the carbon transit time). As example, we apply the model to four management scenarios, i.e., mixed -aged pine, even -aged pine, even -aged spruce, and even -aged mixed forest, and contrast metrics of performance relative to wood production, carbon sequestration, and climate change mitigation potential. While at the end of an 80 yr rotation the even -aged forests held up to 31% more carbon than the mixed -aged forest, the mixed -aged forest was superior during almost the entire rotation when factoring in the carbon retention time away from the atmosphere, i.e., in terms of climate change mitigation potential. Importantly, scenarios that maximize production or amount of carbon stored in the ecosystems are not necessarily the most beneficial for carbon retention away from the atmosphere. These results underline the importance of considering carbon transit time when evaluating forest management options for potential climate change mitigation.

关键词： Boreal forest Wood production Carbon sequestration Transit time Climate change mitigation process-based modeling

来源：评论

学校读者我要写书评

暂无评论

Comprehensive quality assessment of satellite- and model-based soil moisture products against the COSMOS network in Germany

引用

REMOTE SENSING OF ENVIRONMENT 2024年 301卷

作者： Schmidt, Toni Schroen, Martin Li, Zhan Francke, Till Zacharias, Steffen Hildebrandt, Anke Peng, Jian UFZ Helmholtz Ctr Environm Res Dept Remote Sensing Permoserstra 15 D-04318 Leipzig Germany Univ Leipzig Remote Sensing Ctr Earth Syst Res RSC4Earth D-04109 Leipzig Germany UFZ Helmholtz Ctr Environm Res Dept Monitoring & Explorat Technol Permoserstr 15 D-04318 Leipzig Germany Univ Potsdam Inst Environm Sci & Geog Karl Liebknecht Str 24-25 D-14476 Potsdam Germany UFZ Helmholtz Ctr Environm Res Dept Computat Hydrosyst Permoserstr 15 DE-04318 Leipzig Germany Friedrich Schiller Univ Jena Inst Geosci Burgweg 11 D-07749 Jena Germany

Critical to the reliable application of gridded soil moisture products is a thorough assessment of their quality at spatially compatible scales. While previous studies have attempted to evaluate different soil moisture products, comprehensive assessments at the appropriate scale remain challenging and rare. This study explores the potential of the Cosmic-Ray Soil Moisture Observation System (COSMOS) in Germany for effectively mitigating the scale mismatch between soil moisture products and reference measurements. A newly released extensive COSMOS data set provides time series of hectare-scale soil moisture of the main root zone at different locations in Germany and offers a unique opportunity for a comprehensive quality assessment of 15 commonly-used coarse scale soil moisture products. Those are either satellite-based (AMSR2 LPRM, ASCAT H115/H116, Sentinel-1 SSM, SMAP L3E, SMOS L3, ASCAT/Sentinel-1 SWI, SMAP/Sentinel-1 L2, CCI Combined, and NOAA SMOPS) or model based (ERA5-Land, GLDAS-Noah, ASCAT H141/H142, GLEAM, SMAP L4, and SMOS L4). We compared the temporal dynamics of the soil moisture products against that of the COSMOS soil moisture estimates at 21 sites of different land cover types over six years (2015-2020), including the drought of 2018. We found that the model based products generally yield a higher correlation (0.74) and lower unbiased root-mean-square differences (0.05 m3m  3) than the satellite-based products (0.60 and 0.07 m3m  3, respectively) against the COSMOS data in Germany. Notably, the application of the exponential filter significantly improves the performance of the products. Conversely, deseasonalized time series of all selected products demonstrate lower performances across all COSMOS sites. Most products show a considerable positive bias, which limits their usability for the assessment of absolute soil water storage. We also found that the land cover type, mean annual soil moisture, and vertical support have notable influences on the p

关键词： Soil moisture Remote sensing process-based modeling Quality assessment Cosmic-Ray soil moisture observation system (COSMOS) Exponential filter

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：