Spatial Explicit Modeling of Arctic Tundra Landscapes PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Spatial Explicit Modeling of Arctic Tundra Landscapes PDF full book. Access full book title Spatial Explicit Modeling of Arctic Tundra Landscapes by . Download full books in PDF and EPUB format.
Author:
Publisher:
ISBN:
Category : Plant communities
Languages : en
Pages : 324
Get Book Here
Book Description
While many questions regarding human impact on tundra ecosystems are regional in spatial extent, the patch level is the largest scale at which experimental validation is possible. Since the individual organism ultimately responds to perturbations, it is necessary to scale up to higher levels. This in turn requires an understanding of spatial pattern that can be observed at a landscape scale. In this thesis, relationships between the spatial pattern of the physical environment and vegetation pattern of an arctic tundra landscape in the foothills of the Brooks Range, Alaska, are analyzed by testing the hypothesis that the spatial pattern of plant communities can be quantified using topography as the only spatial variable. The hypothesis is first tested by examining the spatial relationship between patterns of the normalized difference vegetation index (NDVI) and the water regime. Using gridded elevation data, a model (T-HYDRO) is developed to generate a 2-dimensional water flow field for the watershed. The results show that pattern of water flow can account for about 43% of the spatial variance in NDVI, supporting the hypothesis. Secondly, the G-model concept is developed to predict tundra community vegetation patterns based on topographic gradients. Maps showing patterns of slope and discharge were used to generate quantitative gradient models. The models predicted vegetation pattern at Imnavait creek (10% of a larger mapped region) with an accuracy of 70%. Validation of models based on the relationships developed at Imnavait Creek watershed resulted in an accuracy in predicted vegetation pattern of about 60% for the entire region; again supporting the hypothesis. The spatial pattern of prediction errors revealed the influence of landscape age and snow drifts. The appendix presents a software toolkit for modeling using spatial data. It is designed to enable access to spatial data using the most modern and widely used programming language C++. The system enables input and output of file formats used by different geographic information systems, comfortable and efficient access to entire layers and single pixels, and includes some fundamental GIS functionality such as map overlay. The usage of the routines is illustrated by several example programs.
Author:
Publisher:
ISBN:
Category : Plant communities
Languages : en
Pages : 324
Get Book Here
Book Description
While many questions regarding human impact on tundra ecosystems are regional in spatial extent, the patch level is the largest scale at which experimental validation is possible. Since the individual organism ultimately responds to perturbations, it is necessary to scale up to higher levels. This in turn requires an understanding of spatial pattern that can be observed at a landscape scale. In this thesis, relationships between the spatial pattern of the physical environment and vegetation pattern of an arctic tundra landscape in the foothills of the Brooks Range, Alaska, are analyzed by testing the hypothesis that the spatial pattern of plant communities can be quantified using topography as the only spatial variable. The hypothesis is first tested by examining the spatial relationship between patterns of the normalized difference vegetation index (NDVI) and the water regime. Using gridded elevation data, a model (T-HYDRO) is developed to generate a 2-dimensional water flow field for the watershed. The results show that pattern of water flow can account for about 43% of the spatial variance in NDVI, supporting the hypothesis. Secondly, the G-model concept is developed to predict tundra community vegetation patterns based on topographic gradients. Maps showing patterns of slope and discharge were used to generate quantitative gradient models. The models predicted vegetation pattern at Imnavait creek (10% of a larger mapped region) with an accuracy of 70%. Validation of models based on the relationships developed at Imnavait Creek watershed resulted in an accuracy in predicted vegetation pattern of about 60% for the entire region; again supporting the hypothesis. The spatial pattern of prediction errors revealed the influence of landscape age and snow drifts. The appendix presents a software toolkit for modeling using spatial data. It is designed to enable access to spatial data using the most modern and widely used programming language C++. The system enables input and output of file formats used by different geographic information systems, comfortable and efficient access to entire layers and single pixels, and includes some fundamental GIS functionality such as map overlay. The usage of the routines is illustrated by several example programs.
Author: James F. Reynolds
Publisher: Springer Science & Business Media
ISBN: 366201145X
Category : Science
Languages : en
Pages : 447
Get Book Here
Book Description
Following the discovery of large petroleum reserves in northern Alaska, the US Department of Energy implemented an integrated field and modeling study to help define potential impacts of energy-related disturbances on tundra ecosystems. This volume presents the major findings from this study, ranging from ecosystem physiology and biogeochemistry to landscape models that quantify the impact of road-building. An important resource for researchers and students interested in arctic ecology, as well as for environmental managers concerned with practical issues of disturbances.
Author: James F. Reynolds
Publisher: Springer
ISBN:
Category : History
Languages : en
Pages : 472
Get Book Here
Book Description
Following the discovery of large petroleum reserves in northern Alaska, the US Department of Energy implemented an integrated field and modeling study to help define potential impacts of energy-related disturbances on tundra ecosystems. This volume presents the major findings from this study, ranging from ecosystem physiology and biogeochemistry to landscape models that quantify the impact of road-building. An important resource for researchers and students interested in arctic ecology, as well as for environmental managers concerned with practical issues of disturbances.
Author: J.D. Tenhunen
Publisher: Springer Science & Business Media
ISBN: 9783540672678
Category : History
Languages : en
Pages : 698
Get Book Here
Book Description
The challenges in ecosystem science encompass a broadening and strengthening of interdisciplinary ties, the transfer of knowledge of the ecosystem across scales, and the inclusion of anthropogenic impacts and human behavior into ecosystem, landscape, and regional models. The volume addresses these points within the context of studies in major ecosystem types viewed as the building blocks of central European landscapes. The research is evaluated to increase the understanding of the processes in order to unite ecosystem science with resource management. The comparison embraces coastal lowland forests, associated wetlands and lakes, agricultural land use, and montane and alpine forests. Techniques for upscaling focus on process modelling at stand and landscape scales and the use of remote sensing for landscape-level model parameterization and testing. The case studies demonstrate ways for ecosystem scientists, managers, and social scientists to cooperate.
Author: David Michael Atkinson
Publisher:
ISBN:
Category :
Languages : en
Pages : 324
Get Book Here
Book Description
Vegetation community patterns and processes are indicators and integrators of climate. Recently, scientists have shown that climate change is most pronounced in circumpolar regions. Arctic ecosystems have traditionally been sequestering carbon and accumulating large carbon stores. However, given enhanced warming in the Arctic, the potential exists for intensified global climate change if these ecosystems transition from sinks to sources of atmospheric CO2. In the Mid and High Arctic, ecosystems exhibit extreme levels of spatial heterogeneity, particularly at landscape scales. High spatial-resolution (e.g., 4m) remote sensing data capture heterogeneous vegetation patterns of the Arctic landscape and have the potential to model ecosystem biophysical properties and CO2 fluxes. The following conditions are required to model arctic ecosystem processes: (i) unique spectral signatures that correspond to variations in the landscape pattern; (ii) models that transform remote sensing data into derivative values pertaining to the landscape; and (iii) field measures of the variables to calibrate and validate the models. First, this research creates an ecosystem classification scheme through ordination, clustering, and spectral-separability of ground cover data to generate ecologically meaningful and spectrally distinct image classifications. Classifications had overall accuracies between 69% - 79% and Kappa values of 0.54 - 0.69. Secondly, biophysical variable models of percent vegetation cover, aboveground biomass, and soil moisture are calibrated and validated using a k-fold cross-validation linear bivariate regression methodology. Percent vegetation cover and percent soil moisture produce the strongest and most consistent results (r2 [greater than or equal to] 0.84 and 0.73) across both study sites. Finally, in situ CO2 exchange rate data, an NDVI model for each component flux, which explains between 42% and 95% of the variation at each site, is generated. Analysis of coincidence indicates that a single model for each component flux can be applied, independent of site. This research begins to fill a gap in the application of high spatial-resolution remote sensing data for modelling Arctic ecosystem biophysical variables and carbon dioxide exchange, particularly in the Canadian Arctic. The results of this research also indicate high levels of functional convergence in ecosystem-level structure and function within Arctic landscapes.
Author: David J. Mladenoff
Publisher: Cambridge University Press
ISBN: 9780521631228
Category : Nature
Languages : en
Pages : 388
Get Book Here
Book Description
Key researchers present newly emerging approaches to computer simulation models of large, forest landscapes.
Author: M. D. Flannigan
Publisher:
ISBN:
Category : Forest fire forecasting
Languages : en
Pages : 64
Get Book Here
Book Description
This report features extended abstracts and summaries of breakout sessions at a workshop that explored opportunities associated with, and limitations of, landscape fire models for boreal & temperate forest ecosystems. Specific topics included modelling gaps & needs, application of fire models for forest & vegetation management, fire effects at landscape scales, computer simulation, multi-scale models, and incorporation of fire into dynamic global vegetation models.
Author:
Publisher:
ISBN:
Category : Arctic regions
Languages : en
Pages : 140
Get Book Here
Book Description
Author: J. D. Tenhunen
Publisher: John Wiley & Sons
ISBN:
Category : Science
Languages : en
Pages : 396
Get Book Here
Book Description
In recent decades, the biosphere has become increasingly stressed, often beyond the point where the internal structure and function of ecosystems are sustained. We have experienced an intensified “exploration” of natural system resources to support agricultural and forest production, to provide water for human consumption, to supply the needs of industrial processes, and to provide, in addition, attractive, diverse landscapes for recreation and tourism. Exceeding thresholds via anthropogenic disturbance that results in degradation of ecosystems is dangerous, since the system-level effects and feedbacks (e.g., soil erosion, famine, polluted drinking water, etc.) are highly undesirable. Finding appropriate compromises in resource use that satisfy existing competitive interests and result in sound environmental management, especially in densely populated regions, requires an improved understanding of the trade-offs that accompany changes in “exploitation” or altered resource allocation at regional and landscape scales. Progress on landscape-level understanding of coupled water, carbon, and nitrogen budgets is limited by a lack of commitment to a rigorous development and application of synthetic techniques (e.g., strongly linked remote sensing studies, geographic information system applications, computer simulation modeling, and ecosystem experimentation) more than by basic site-level measurement alone. Possible research approaches that will contribute to new use of ecosystem knowledge in a landscape and regional context were considered by this Dahlem Workshop. The importance of conducting improved landscape and regional assessment of ecosystem function as input to global scale efforts of the International Geosphere-Biosphere Programme is a major theme of this book.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
This Modeling Archive is in support of an NGEE Arctic discussion paper under review and available at http://www.the-cryosphere-discuss.net/tc-2016-29/. Vast carbon stocks stored in permafrost soils of Arctic tundra are under risk of release to atmosphere under warming climate. Ice--wedge polygons in the low-gradient polygonal tundra create a complex mosaic of microtopographic features. The microtopography plays a critical role in regulating the fine scale variability in thermal and hydrological regimes in the polygonal tundra landscape underlain by continuous permafrost. Modeling of thermal regimes of this sensitive ecosystem is essential for understanding the landscape behaviour under current as well as changing climate. We present here an end-to-end effort for high resolution numerical modeling of thermal hydrology at real-world field sites, utilizing the best available data to characterize and parameterize the models. We develop approaches to model the thermal hydrology of polygonal tundra and apply them at four study sites at Barrow, Alaska spanning across low to transitional to high-centered polygon and representative of broad polygonal tundra landscape. A multi--phase subsurface thermal hydrology model (PFLOTRAN) was developed and applied to study the thermal regimes at four sites. Using high resolution LiDAR DEM, microtopographic features of the landscape were characterized and represented in the high resolution model mesh. Best available soil data from field observations and literature was utilized to represent the complex hetogeneous subsurface in the numerical model. This data collection provides the complete set of input files, forcing data sets and computational meshes for simulations using PFLOTRAN for four sites at Barrow Environmental Observatory. It also document the complete computational workflow for this modeling study to allow verification, reproducibility and follow up studies.
