Download or read book Description Calibration and Sensitivity Analysis of the Local Ecosystem Submodel of a Global Model of Carbon and Nitrogen Cycling and the Water Balance of the Terrestrial Biosphere written by and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The importance of uncertainty and sensitivity analysis in process based models of carbon and nitrogen cycling in terrestrial ecosystems with particular emphasis on forest ecosystems selected papers from a workshop organized by the International Society for Ecological Modelling ISEM at the third Biennial Meeting of the International Environmental Modelling and Software Society IEMSs in Burlington Vermont USA August 9 13 2006 written by International Environmental Modelling and Software Society and published by . This book was released on 2008 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Global Sensitivity Analysis and Parameter Calibration for an Ecosystem Carbon Model written by and published by . This book was released on 2013 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1996 with total page 592 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Global Sensitivity Analysis Probabilistic Calibration and Predictive Assessment for the Data Assimilation Linked Ecosystem Carbon Model written by and published by . This book was released on 2015 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this paper we propose a probabilistic framework for an uncertainty quantification (UQ) study of a carbon cycle model and focus on the comparison between steady-state and transient simulation setups. A global sensitivity analysis (GSA) study indicates the parameters and parameter couplings that are important at different times of the year for quantities of interest (QoIs) obtained with the data assimilation linked ecosystem carbon (DALEC) model. We then employ a Bayesian approach and a statistical model error term to calibrate the parameters of DALEC using net ecosystem exchange (NEE) observations at the Harvard Forest site. The calibration results are employed in the second part of the paper to assess the predictive skill of the model via posterior predictive checks.
Download or read book Assessing Uncertainty in Models of the Ocean Carbon Cycle written by Vivian Scott and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis I explore the effect of parameter uncertainty in ocean biogeochemical models on the calculation of carbon uptake by the ocean. The ocean currently absorbs around a quarter of the annual anthropogenic CO2 emissions to the atmosphere [Scholes et al., 2009], slowing the increase in radiative forcing associated with the increasing atmospheric CO2 concentration. Ocean biogeochemical models have been developed to study the role of the ocean ecosystem in this process. Such models consist of a greatly simplified representation of the hugely complex ocean ecosystem. This simplification requires extensive parameterisation of the biological processes that convert inorganic carbon to and from organic carbon in the ocean. The HadOCC ocean biogeochemical model is a Nutrient-Phytoplankton-Zooplankton-Detritus (NPZD) model that is used to represent the role of the ocean ecosystem in the global carbon cycle in the HadCM3 and FAMOUS GCMs. HadOCC uses twenty parameters to control the processes of biological growth, mortality, grazing and detrital sinking that control the uptake and cycling of carbon in the ocean ecosystem. These parameters represent highly complex and in some cases incompletely understood biological processes, and as a result are uncertain in value. A sensitivity analysis is performed to identify the HadOCC parameters that due to uncertainty in value have the greatest possible effect on the exchange of CO2 between the atmosphere and the ocean--the air-sea CO2 flux. These are found to be the parameters that control phytoplankton growth in the well lit surface ocean, the formation of carbonate by marine organisms and the sinking of biological detritus. The uncertainty in these parameters is found to cause changes to the air-sea CO2 flux calculated by the FAMOUS GCM. The initial effect of these changes is equivalent to the order of the error of current estimates of the net annual carbon uptake by the ocean (2.2 ± 0.3 Pg C y-1 [Gruber et al., 2009], 2.2 ± 0.5 Pg C y-1 [Denman et al., 2007]). This indicates that while the effect of ocean biogeochemical parameter uncertainty is non-negligible, it is within the bounds of the uncertainty of the total (inorganic and organic) ocean carbon system, and is considerably less than the uncertainty in the carbon uptake of the terrestrial biosphere [Houghton, 2007]. However, as the ocean plays a crucial role in the global carbon cycle and the regulation of the Earth's climate, further understanding and better modelling of the role of the ocean ecosystem in the global carbon cycle and its reaction to anthropogenic climate forcing remains important.
Download or read book Land Carbon Cycle Modeling written by Yiqi Luo and published by . This book was released on 2022 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon moves through the atmosphere, through the oceans, onto land, and into and between various ecosystems. This cycling has a large effect on climate - changing geographic patterns of rainfall and the frequency of extreme weather. The impact of changes in global carbon cycling are altered as the use of fossil fuels add carbon to the cycle. This book addresses the crucial question of how to assess, evaluate, and estimate the potential impact of the additional carbon to the global carbon cycle. The contributors describe a set of models for exploring ecological questions regarding changes in carbon cycling; provide background for developing new models; employs data assimilation techniques for model improvement; and do real- or near-time ecological forecasting for decision support. This book strives to balance theoretical considerations, technical details, and applications of ecosystem modeling for research, assessment, and crucial decision making. Key Features Helps readers understand, implement and criticize carbon cycling models Does not require computer programming skills or deep knowledge of mathematics Describes a suite of modeling skills - modeling questions, building models, data assimilation Combines modeling with statistical analysis of models Introduces data assimilation, statistical analysis, Markov chain Mote Carlo methods, and decision supporting systems
Download or read book Sensitivity Analysis of a Carbon Simulation Model and Its Application in a Montane Forest Environment written by Shiyong Xu and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Carbon Dioxide and Terrestrial Ecosystems written by George W. Koch and published by Elsevier. This book was released on 1995-12-21 with total page 463 pages. Available in PDF, EPUB and Kindle. Book excerpt: The importance of carbon dioxide extends from cellular to global levels of organization and potential ecological deterioration may be the result of increased CO2 in our atmosphere. Recently, the research emphasis shifted from studies of photosynthesis pathways and plant growth to ground-breaking studies of carbon dioxide balances in ecosystems, regions, and even the entire globe. Carbon Dioxide and Terrestrial Ecosystems addresses these new areas of research. Economically important woody ecosystems are emphasized because they have substantial influence on global carbon dioxide balances. Herbaceous ecosystems (e.g., grasslands, prairies, wetlands) and crop ecosystems are also covered. The interactions among organisms, communities, and ecosystems are modeled, and the book closes with an important synthesis of this growing nexus of research. Carbon Dioxide and Terrestrial Ecosystems is a compilation of detailed scientific studies that reveal how ecosystems generally, and particular plants specifically, respond to changed levels of carbon dioxide. - Contributions from an international team of experts - Empirical examination of the actual effects of carbon dioxide - Variety of terrestrial habitats investigated - Specific plants and whole ecosystems offered as studies
Download or read book The Carbon Cycle written by T. M. L. Wigley and published by Cambridge University Press. This book was released on 2005-08-22 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reducing carbon dioxide (CO2) emissions is imperative to stabilizing our future climate. Our ability to reduce these emissions combined with an understanding of how much fossil-fuel-derived CO2 the oceans and plants can absorb is central to mitigating climate change. In The Carbon Cycle, leading scientists examine how atmospheric carbon dioxide concentrations have changed in the past and how this may affect the concentrations in the future. They look at the carbon budget and the "missing sink" for carbon dioxide. They offer approaches to modeling the carbon cycle, providing mathematical tools for predicting future levels of carbon dioxide. This comprehensive text incorporates findings from the recent IPCC reports. New insights, and a convergence of ideas and views across several disciplines make this book an important contribution to the global change literature.
Download or read book Spatially Explicit Modeling of Hydrologically Controlled Carbon Cycles in a Boreal Ecosystem written by Ajit Govind and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Environmental Variability and System Heterogeneity in Terrestrial Biogeochemical Models written by Carlos Alberto Sierra and published by . This book was released on 2009 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ecosystems are highly heterogeneous systems subjected to important levels of environmental variability; however, it is common in terrestrial biogeochemical models to assume homogeneous properties of the elements of the system or constant environmental conditions. For some processes, heterogeneity in these models is treated very simplistically, but there is not much information about the advantages of including more complex representations in these models. By environmental variability I refer to the continuous changes of abiotic drivers in ecosystems, mainly climatic conditions. System heterogeneity is treated here as the diversity of elements that compose an ecosystem and respond differently to biotic and abiotic drivers. In this dissertation I performed a theoretical analysis to evaluate the consequences of ignoring heterogeneity and variability on the representation of carbon and nitrogen cycling in terrestrial biogeochemical models. For this purpose I used tools from probability theory and simulation models to test the hypothesis that ignoring heterogeneity and variability excludes a variety of system properties and behaviors that cannot be obtained with simpler models. Explicit treatments of climatic variability showed that changes in temperature variance alone can modify the amounts of respiration and carbon storage in ecosystems. Additionally, changes in temperature variance can modify predictions solely based on changes in temperature averages. This behavior is strongly dependent on the degree and nature of nonlinearity in ecosystems. Effects of system heterogeneity on carbon and nitrogen cycling are also strongly influenced by nonlinearities. Extrapolations of average system behavior are only valid when the system is linear and the elements of the system are distributed homogeneously or symmetrically around an average value. In all other cases, the nonlinearity of the system and the distribution of its elements produce complex behaviors that are impossible to predict with simple models.
Download or read book Modeling the Role of Terrestrial Ecosystems in the Global Carbon Cycle written by and published by . This book was released on 1980 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A model for the global biogeochemical cycle of carbon which includes a five-compartment submodel for circulation in terrestrial ecosystems of the world is presented. Although this terrestrial submodel divides carbon into compartments with more functional detail than previous models, the variability in carbon dynamics among ecosystem types and in different climatic zones is not adequately treated. A new model construct which specifically treats this variability by modeling the distribution of ecosystem types as a function of climate on a 0.5° latitude by 0.5° longitude scale of resolution is proposed.
Download or read book Carbon water Cycling in the Critical Zone written by and published by . This book was released on 2016 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the largest knowledge gaps in environmental science is the ability to understand and predict how ecosystems will respond to future climate variability. The links between vegetation, hydrology, and climate that control carbon sequestration in plant biomass and soils remain poorly understood. Soil respiration is the second largest carbon flux of terrestrial ecosystems, yet there is no consensus on how respiration will change as water availability and temperature co-vary. To address this knowledge gap, we use the variation in soil development and topography across an elevation and climate gradient on the Front Range of Colorado to conduct a natural experiment that enables us to examine the co-evolution of soil carbon, vegetation, hydrology, and climate in an accessible field laboratory. The goal of this project is to further our ability to combine plant water availability, carbon flux and storage, and topographically driven hydrometrics into a watershed scale predictive model of carbon balance. We hypothesize: (i) landscape structure and hydrology are important controls on soil respiration as a result of spatial variability in both physical and biological drivers: (ii) variation in rates of soil respiration during the growing season is due to corresponding shifts in belowground carbon inputs from vegetation; and (iii) aboveground carbon storage (biomass) and species composition are directly correlated with soil moisture and therefore, can be directly related to subsurface drainage patterns.
Download or read book Importance of Carbon nitrogen Interactions and Ozone on Ecosystem Hydrology During the 21st Century written by Benjamin Seth Felzer and published by . This book was released on 2009 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of various aspects of global change (e.g., climate change, changes in the chemistry of the atmosphere, such as CO2 and O3, and land-use change) on the hydrologic cycle are becoming an important research area. For example, with respect to increases in atmospheric CO2, recent work supports the contention that there will be reduced evapotranspiration and therefore increased water availability in a CO2-rich world. Our new research on this topic suggests that various aspects of global change combine to affect hydrology in terrestrial ecosystems, and that it is particularly important to include carbon-nitrogen interactions in these studies. We have developed a new version of the Terrestrial Ecosystems Model (TEM) to examine the effects of carbon-nitrogen interactions on the water cycle. This new version includes explicit modeling of the stomatal exchange of CO2 and water, as well as a new approach to carbon and nitrogen allocation in plants. Using this new version of TEM, we have performed a range of site-level and regional experiments across the eastern United States. For example, using data from Harvard Forest, MA, a predominantly deciduous mixed forest, we ran two transient simulations from 1700 to 2100, with and without considering nitrogen limitations on plant productivity. In both of these simulations, we allowed CO2 to double by 2100, but maintained present-day climate. In these two experiments, we found that runoff increased through the 21st century in response to elevated atmospheric CO2. Without nitrogen limitation on plant productivity, the increase in runoff was 12%. However, with nitrogen limitation on plant productivity, the increase in runoff nearly doubled to 21%. This difference in runoff response was the result of a stronger transpiration reduction associated with a smaller increase in photosynthesis in the nitrogen limitation case. In this resentation we will discuss a set of site-level and regional experiments that explore the effects of carbon-nitrogen interactions on the water cycle in the context of different combinations of global changes including climate changes, changes in nitrogen deposition, and changes in tropospheric ozone. Since the carbon and water cycles are tightly coupled, future considerations of ecohydrology must take into account carbon-nitrogen interactions and other multiple stresses that strongly influence the carbon cycle.
Download or read book Quantifying and Mitigating the Contribution of Model Uncertainty to Predictions of the Terrestrial Carbon Cycle written by Caroline Alexa Famiglietti and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The terrestrial biosphere is an integral component of the Earth system, serving as a buffer against the impacts of anthropogenic climate change and providing a wealth of ecosystem services to communities across the globe. However, its behavior and responses to environmental perturbations are challenging to model, mainly due to uncertainties involving model structure and parameterization. Despite a proliferation of targeted model development efforts, persistent disagreement between predictions from different state-of-the-art terrestrial biosphere models hinders the establishment and prioritization of robust management and restoration initiatives. In this dissertation, I develop methods for quantifying and mitigating the role of model uncertainty in predictions of the terrestrial carbon cycle. This was made possible via diverse, multi-scale Earth observations, which I integrate within a flexible ecosystem model--fusion framework. Together, this research provides new insight into the inter-relationship between structural and parametric uncertainties, and also highlights opportunities for using novel data to develop model parameterization strategies that yield realistic variability across the global land surface.
