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A blueprint for process-based modeling of uncertain hydrological systems

WATER RESOURCES RESEARCH 2012年第9期48卷

作者： Montanari, Alberto Koutsoyiannis, Demetris Univ Bologna Dept Civil Environm & Mat Engn DICAM IT-40136 Bologna Italy Natl Tech Univ Athens Dept Water Resources & Environm Engn Zografos Greece

We present a probability based theoretical scheme for building process-based models of uncertain hydrological systems, thereby unifying hydrological modeling and uncertainty assessment. Uncertainty for the model output is assessed by estimating the related probability distribution via simulation, thus shifting from one to many applications of the selected hydrological model. Each simulation is performed after stochastically perturbing input data, parameters and model output, this latter by adding random outcomes from the population of the model error, whose probability distribution is conditioned on input data and model parameters. Within this view randomness, and therefore uncertainty, is treated as an inherent property of hydrological systems. We discuss the related assumptions as well as the open research questions. The theoretical framework is illustrated by presenting real-world and synthetic applications. The relevant contribution of this study is related to proposing a statistically consistent simulation framework for uncertainty estimation which does not require model likelihood computation and simplification of the model structure. The results show that uncertainty is satisfactorily estimated although the impact of the assumptions could be significant in conditions of data scarcity.

关键词： hydrology process-based modeling stochastic modeling uncertainty

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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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Sensitivity analysis of tree phenology models reveals increasing sensitivity of their predictions to winter chilling temperature and photoperiod with warming climate

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ECOLOGICAL MODELLING 2019年 411卷 108805-000页

作者： Gauzere, Julie Lucas, Camille Ronce, Ophelie Davi, Hendrik Chuine, Isabelle Univ Montpellier CNRS CEFE Univ Paul Valery Montpellier 3EPHEIRD Montpellier France Univ Montpellier Inst Sci Evolut CNRS IRDEPHE Montpellier France INRA URFM UR0629 F-84914 Avignon France Univ Edinburgh Sch Biol Sci Inst Evolutionary Biol Charlotte Auerbach Rd Edinburgh EH9 3FL Midlothian Scotland

The phenology of plants is a major driver of agro-ecosystem processes and biosphere feedbacks to the climate system. Phenology models are classically used in ecology and agronomy to project future phenological changes. With our increasing understanding of the environmental cues affecting bud development, phenology models also increase in complexity. But, we expect these cues, and the underlying physiological processes, to have varying influence on bud break date predictions depending on the specific weather patterns in winter and spring. Here, we evaluated the parameter sensitivity of state-of-the-art process-based phenology models that have been widely used to predict forest tree species phenology. We used sensitivity analysis to compare the behavior of models with increasing complexity under specific climatic conditions. We thus assessed whether the influence of the parameters and modeled processes on predictions varies with winter and spring temperatures. We found that the prediction of the bud break date was mainly affected by the response to forcing temperature under current climatic conditions. However, the impact of the parameters driving the response to chilling temperatures and to photoperiod on the prediction of the models increased with warmer winter and spring temperatures. Interaction effects between parameters played an important role on the prediction of models, especially for the most complex models, but did not affect the relative influence of parameters on bud break dates. Our results highlighted that a stronger focus should be given to the characterization of the reaction norms to both forcing and chilling temperature to predict accurately bud break dates in a larger range of climatic conditions and evaluate the evolutionary potential of phenological traits with climate change.

关键词： Sensitivity analysis process-based modeling Bud development Forcing temperature Chilling temperature Photoperiod

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Looking beyond the mean: Drivers of variability in postfire stand development of conifers in Greater Yellowstone

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FOREST ECOLOGY AND MANAGEMENT 2018年 430卷 460-471页

作者： Braziunas, Kristin H. Hansen, Winslow D. Seidl, Rupert Rammer, Werner Turner, Monica G. Univ Wisconsin Madison Dept Integrat Biol Birge Hall430 Lincoln Dr Madison WI 53706 USA Univ Nat Resources & Life Sci BOKU Vienna Inst Silviculture Dept Forest & Soil Sci Peter Jordan Str 82 A-1190 Vienna Austria

High-severity, infrequent fires in forests shape landscape mosaics of stand age and structure for decades to centuries, and forest structure can vary substantially even among same-aged stands. This variability among stand structures can affect landscape-scale carbon and nitrogen cycling, wildlife habitat availability, and vulnerability to subsequent disturbances. We used an individual-based forest process model (iLand) to ask: Over 300 years of postfire stand development, how does variation in early regeneration densities versus abiotic conditions influence among-stand structural variability for four conifer species widespread in western North America? We parameterized iLand for lodgepole pine (Pins contorta var. latifolia), Douglas-fir (Pseudotsuga menziesu var. glauca), Engelmann spruce (Picea engelmannu), and subalpine fir (Abies lasiocarpa) in Greater Yellowstone (USA). Simulations were initialized with field data on regeneration following stand-replacing fires, and stand development was simulated under historical climatic conditions without further disturbance. Stand structure was characterized by stand density and basal area. Stands became more similar in structure as time since fire increased. Basal area converged more rapidly among stands than tree density for Douglas-fir and lodgepole pine, but not for subalpine fir and Engelmann spruce. For all species, regeneration-driven variation in stand density persisted for at least 99 years postfire, and for lodgepole pine, early regeneration densities dictated among-stand variation for 217 years. Over time, stands shifted from competition-driven convergence to environment-driven divergence, in which variability among stands was maintained or increased. The relative importance of drivers of stand structural variability differed between density and basal area and among species due to differential species traits, growth rates, and sensitivity to intraspecific competition versus abiotic conditions. Understanding dynami

关键词： Stand structure Variability Forest development process-based modeling Greater Yellowstone Ecosystem Wildfire

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A process-based MODEL FOR CATTLE MANURE COMPOST WINDROWS: PART 1. MODEL DESCRIPTION

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TRANSACTIONS OF THE ASABE 2017年第3期60卷 877-892页

作者： Bonifacio, H. F. Rotz, C. A. Richard, T. L. Penn Dept Environm Protect Northwest Reg Off Meadville PA USA ARS USDA Pasture Syst & Watershed Management Res Unit University Pk PA USA Penn State Univ Dept Agr & Biol Engn University Pk PA 16802 USA

Composting is an alternative management practice for handling and storing manure in intensive cattle production systems. With composting, cattle manure is converted into a soil amendment with improved nutrient and physical properties and is easier to handle. Despite its benefits, composting can produce large amounts of gaseous carbon (C) and nitrogen (N) emissions that include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and ammonia (NH3). A process-based model for cattle manure compost windrows was developed and incorporated into the Integrated Farm System Model (IFSM, v. 4.3), a whole-farm simulation model of crop, dairy, and beef production systems. Designed to simulate the different processes that influence C and N balances in windrows, the compost windrow model predicts changes in C (organic C, microbial C) and N (organic N, microbial N, ammonium (NH4+-N), nitrate (NO3--N)) contents in the windrow;CO2, CH4, N2O, and NH3 emissions throughout composting;and corresponding C and N losses. To increase its accuracy in simulating the different processes occurring during composting, the compost windrow model was also designed to predict environmental conditions within windrows, which include moisture content, temperature, and oxygen availability, and changes in windrow material physical properties, such as bulk and particle densities. modeling routines and relationships of the compost windrow model are described. Evaluation of its performance in predicting windrow environmental conditions, physical and chemical properties, and gaseous emissions is documented in an accompanying article.

关键词： Cattle manure Composting Emissions IFSM process-based modeling

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A process-based MODEL FOR CATTLE MANURE COMPOST WINDROWS: PART 2. MODEL PERFORMANCE AND APPLICATION

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TRANSACTIONS OF THE ASABE 2017年第3期60卷 893-913页

A model was developed and incorporated into the Integrated Farm System Model (IFSM, v.4.3) that simulates important processes occurring during windrow composting of manure. The model, documented in an accompanying article, predicts changes in windrow properties and conditions and the resulting emissions of C and N. Our objective in this article was to evaluate the performance of the compost windrow model. Model predictions were compared to published data from an independent cattle manure composting study that characterized static (no turning) and turned windrows composted over a 188-day period. The model did very well in simulating C and N losses for the turned windrow treatment, with predicted and measured cumulative C losses of 78% and 77%, respectively, and cumulative N losses of 55% and 57%, respectively, by day 99 of composting. By day 188 of composting, predicted cumulative N loss (56%) differed from measured (58%) by 2 percentage points only, whereas predicted cumulative C loss matched the corresponding measured value (80%). For the static windrow treatment, the model also did well in simulating cumulative C loss by day 99, with a difference of 5 percentage points between predicted (50%) and measured (45%) values. On the other hand, there was a difference of 12 percentage points between predicted (31%) and measured (19%) cumulative N losses for the static windrow by day 99. This discrepancy in simulating N loss for the static windrow treatment was not surprising, as the NH3 biofiltration effect of the finished compost cover on the actual static windrow was not modeled. After simulating the turning of the static windrow treatment on day 99, predicted and measured cumulative N losses by day 188 were equal at 44%. With the compost windrow model as a component, IFSM can be used to evaluate gaseous emissions from composted manure as influenced by windrow management practices and environmental conditions, along with other aspects of performance, environmental impac

关键词： Cattle manure Composting Emissions IFSM process-based modeling

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Analyzing the Effects of Growing Season Length on the Net Ecosystem Production of an Alpine Grassland Using Model-Data Fusion

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ECOSYSTEMS 2018年第5期21卷 982-999页

作者： Scholz, Katharina Hammerle, Albin Hiltbrunner, Erika Wohlfahrt, Georg Univ Innsbruck Inst Okol Sternwartestr 15 A-6020 Innsbruck Austria Univ Basel Inst Bot Totengasslein 3 CH-4051 Basel Switzerland

Alpine ecosystems are, similar to arctic ecosystems, characterized by a very long snow season. Previous studies investigating arctic or alpine ecosystems have shown that winter CO2 effluxes can dominate the annual balance and that the timing and duration of the snow cover plays a crucial role for plant growth and phenology and might also influence the growing season ecosystem CO2 strength and dynamics. The objective of this study was to analyze seasonal and annual CO2 balances of a grassland site at an elevation of 2440 m a.s.l in the Swiss central Alps. We continuously measured the NEP using the eddy covariance method from June 2013 to October 2014, covering two growing seasons and one winter. We analyzed the influence of snow melt date on the CO2 exchange dynamics at this site, because snow melt differed about 24 days between the 2 years. To this end, we employed a process-based ecosystem carbon cycling model to disentangle the co-occurring effects of growing season length, environmental conditions during the growing season, and physiological/structural properties of the canopy on the ecosystem carbon balance. During the measurement period, the site was a net sink for CO2 although winter efflux contributed significantly to the total balance. The cumulative growing season NEP as well as mean and maximum daily CO2 uptake rates was lower during the year with the later snow melt, and the results indicated that the differences were mainly due to differing growing season lengths.

关键词： Carbon uptake period CO2 balance eddy covariance high elevation grassland process-based modeling Swiss Alps winter respiration

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It takes a few to tango: changing climate and fire regimes can cause regeneration failure of two subalpine conifers

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ECOLOGY 2018年第4期99卷 966-977页

作者： Hansen, Winslow D. Braziunas, Kristin H. Rammer, Werner Seidl, Rupert Turner, Monica G. Univ Wisconsin Dept Integrat Biol Madison WI 53706 USA Univ Nat Resources & Life Sci BOKU Dept Forest & Soil Sci Inst Silviculture Vienna Austria

Environmental change is accelerating in the 21st century, but how multiple drivers may interact to alter forest resilience remains uncertain. In forests affected by large high-severity disturbances, tree regeneration is a resilience linchpin that shapes successional trajectories for decades. We modeled stands of two widespread western U.S. conifers, Douglas-fir (Pseudotsuga menziesii var. glauca), and lodgepole pine (Pinus contorta var. latifolia), in Yellowstone National Park (Wyoming, USA) to ask (1) What combinations of distance to seed source, fire return interval, and warming-drying conditions cause postfire tree-regeneration failure? (2) If postfire tree regeneration was successful, how does early tree density differ under future climate relative to historical climate? We conducted a stand-level (1ha) factorial simulation experiment using the individual-based forest process model iLand to identify combinations of fire return interval (11-100yr), distance to seed source (50-1,000m), and climate (historical, mid-21st century, late-21st century) where trees failed to regenerate by 30-yr postfire. If regeneration was successful, we compared stand densities between climate periods. Simulated postfire regeneration were surprisingly resilient to changing climate and fire drivers. Douglas-fir regeneration failed more frequently (55%) than lodgepole pine (28% and 16% for non-serotinous and serotinous stands, respectively). Distance to seed source was an important driver of regeneration failure for Douglas-fir and non-serotinous lodgepole pine;regeneration never failed when stands were 50m from a seed source and nearly always failed when stands were 1km away. Regeneration of serotinous lodgepole pine only failed when fire return intervals were 20yr and stands were far (1km) from a seed source. Warming climate increased regeneration success for Douglas-fir but did not affect lodgepole pine. If regeneration was successful, postfire density varied with climate. Douglas-fir

关键词： climate change drought forest resilience process-based modeling seedling establishment succession wildfire Yellowstone National Park

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Plant Traits are Key Determinants in Buffering the Meteorological Sensitivity of Net Carbon Exchanges of Arctic Tundra

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JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES 2018年第9期123卷 2675-2694页

作者： Lopez-Blanco, Efren Lund, Magnus Christensen, Torben R. Tamstorf, Mikkel P. Smallman, Thomas L. Slevin, Darren Westergaard-Nielsen, Andreas Hansen, Birger U. Abermann, Jakob Williams, Mathew Aarhus Univ Dept Biosci Arctic Res Ctr Roskilde Denmark Univ Edinburgh Sch Geosci Edinburgh Midlothian Scotland Lund Univ Dept Phys Geog & Ecosyst Sci Lund Sweden Univ Copenhagen Dept Geosci & Nat Resource Management Ctr Permafrost CENPERM Copenhagen Denmark Greenland Survey Asiaq Nuuk Greenland

The climate sensitivity of carbon (C) cycling in Arctic terrestrial ecosystems is a major unknown in the Earth system. There is a lack of knowledge about the mechanisms that drive the interactions between photosynthesis, respiration, and changes in C stocks across full annual cycles in Arctic tundra. We use a calibrated and validated model (soil-plant-atmosphere;SPA) to estimate net ecosystem exchange (NEE), gross primary production (GPP), ecosystem respiration (R-eco), and internal C processing across eight full years. SPA's carbon flux estimates are validated with observational data obtained from the Greenland Ecosystem Monitoring program in West Greenland tundra. Overall, the model explained 73%, 73%, and 50% of the variance in NEE, GPP, and R-eco, respectively, and 85% of the plant greenness variation. Flux data highlighted the insensitivity of growing season NEE to interannual meteorological variability, due to compensatory responses of photosynthesis and ecosystem respiration. In this modelling study, we show that this NEE buffering is the case also for full annual cycles. We show through a sensitivity analysis that plant traits related to nitrogen are likely key determinants in the compensatory response, through simulated links to photosynthesis and plant respiration. Interestingly, we found a similar temperature sensitivity of the trait-flux couplings for GPP and R-eco, suggesting that plant traits drive the stabilization of NEE. Further, model analysis indicated that wintertime periods decreased the C sink by 60%, mostly driven by litter heterotrophic respiration. This result emphasizes the importance of wintertime periods and allows a more comprehensive understanding of full annual C dynamics.

关键词： Arctic tundra ecosystem exchange gross primary production ecosystem respiration plant traits process-based modeling

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Underestimation of the Tambora effects in North American taiga ecosystems

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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

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