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291
Multi-angle Imaging SpectroRadiometer (MISR) instrument description and experiment overview. IEEE Transaction on Geoscience and Remote Sensing
, 2005
"... instrument is scheduled for launch aboard the first of the Earth Observing System (EOS) spacecraft, EOS-AM1. MISR will provide global, radiometrically calibrated, georectified, and spatially coregistered imagery at nine discrete viewing angles and four visible/near-infrared spectral bands. Algorithm ..."
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Cited by 125 (24 self)
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instrument is scheduled for launch aboard the first of the Earth Observing System (EOS) spacecraft, EOS-AM1. MISR will provide global, radiometrically calibrated, georectified, and spatially coregistered imagery at nine discrete viewing angles and four visible/near-infrared spectral bands. Algorithms specifically developed to capitalize on this measurement strategy will be used to retrieve geophysical products for studies of clouds, aerosols, and surface radiation. This paper provides an overview of the as-built instrument characteristics and the application of MISR to remote sensing of the earth. Index Terms—Earth, remote sensing. I.
Parameterization and sensitivity analysis of the BIOME-BGC terrestrial ecosystem model: Net primary production controls
- Earth Interactions
, 2000
"... ABSTRACT: Ecosystem simulation models use descriptive input parameters to establish the physiology, biochemistry, structure, and allocation patterns of vegetation functional types, or biomes. For single-stand simulations it is possible to measure required data, but as spatial resolution increases, s ..."
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Cited by 82 (8 self)
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ABSTRACT: Ecosystem simulation models use descriptive input parameters to establish the physiology, biochemistry, structure, and allocation patterns of vegetation functional types, or biomes. For single-stand simulations it is possible to measure required data, but as spatial resolution increases, so too does data unavailability. Generalized biome parameterizations are then required. Undocumented parameter selection and unknown model sensitivity to parameter variation for larger-resolution simulations are currently the major limitations to global and regional modeling. The authors present documented input parameters for a process-based ecosystem simulation model, BIOME– BGC, for major natural temperate biomes. Parameter groups include the following: turnover and mortality; allocation; carbon to nitrogen ratios (C:N); the percent of plant material in labile, cellulose, and lignin pools; leaf morphology; leaf conductance rates and limitations; canopy water interception and light extinction; and the percent of leaf nitrogen in Rubisco (ribulose bisphosphate-1,5-carboxylase/oxygenase) (PLNR). Using climatic and site de-
An integrated model of soil, hydrology, and vegetation for carbon dynamics in wetland ecosystems, Global Biogeochem
- Cy
"... [1] Wetland ecosystems are an important component in global carbon (C) cycles and may exert a large influence on global climate change. Predictions of C dynamics require us to consider interactions among many critical factors of soil, hydrology, and vegetation. However, few such integrated C models ..."
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Cited by 40 (8 self)
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[1] Wetland ecosystems are an important component in global carbon (C) cycles and may exert a large influence on global climate change. Predictions of C dynamics require us to consider interactions among many critical factors of soil, hydrology, and vegetation. However, few such integrated C models exist for wetland ecosystems. We developed a simulation model, Wetland-DNDC, for C dynamics including methane (CH 4 ) emissions in wetland ecosystems. The general structure of the model was adopted from PnET-N-DNDC, a process-oriented biogeochemical model that simulates C and N dynamics in upland forest ecosystems. We developed new functions and algorithms to capture the unique features of C dynamics under wetland conditions. Major modifications were made which focus on quantifying water table dynamics, soil thermal dynamics, growth of mosses and herbaceous plants, and soil biogeochemical processes under anaerobic conditions. In this paper, we report new developments made for Wetland-DNDC, as well as tests against observations from three wetland sites in Northern America. Validation results show that the model's predictions are in good agreement with measurements of water table dynamics, soil temperature, CH 4 fluxes, net ecosystem productivity (NEP), and annual C budgets. Sensitivity analysis indicates that the most critical input factors include temperature, water outflow parameters, initial soil C content, and plant photosynthesis capacity. NEP and CH 4 emissions are sensitive to many of the input variables required by different components of the model. These results suggest that integrated modeling with soil, hydrology, vegetation, and climate is essential to predict C cycles in wetland ecosystems.
Modeling the soil thermal and carbon dynamics of a fire chronosequence in interior
, 2003
"... [1] In this study, the dynamics of soil thermal, hydrologic, and ecosystem processes were coupled to project how the carbon budgets of boreal forests will respond to changes in atmospheric CO2, climate, and fire disturbance. The ability of the model to simulate gross primary production and ecosystem ..."
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Cited by 36 (19 self)
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[1] In this study, the dynamics of soil thermal, hydrologic, and ecosystem processes were coupled to project how the carbon budgets of boreal forests will respond to changes in atmospheric CO2, climate, and fire disturbance. The ability of the model to simulate gross primary production and ecosystem respiration was verified for a mature black spruce ecosystem in Canada, the age-dependent pattern of the simulated vegetation carbon was verified with inventory data on aboveground growth of Alaskan black spruce forests, and the model was applied to a postfire chronosequence in interior Alaska. The comparison between the simulated soil temperature and field-based estimates during the growing season (May to September) of 1997 revealed that the model was able to accurately simulate monthly temperatures at 10 cm (R> 0.93) for control and burned stands of the fire chronosequence. Similarly, the simulated and field-based estimates of soil respiration for control and burned stands were correlated (R = 0.84 and 0.74 for control and burned stands, respectively). The simulated and observed decadal to centuryscale dynamics of soil temperature and carbon dynamics, which are represented by mean monthly values of these variables during the growing season, were correlated among
2002: Modelling vegetation as a dynamic component in soil–vegetation–atmosphere– transfer schemes and hydrological models
- Rev. Geophys
"... [1] Vegetation affects the climate by modifying the energy, momentum, and hydrologic balance of the land surface. Soil-vegetation-atmosphere transfer (SVAT) schemes explicitly consider the role of vegetation in affecting water and energy balance by taking into account its physiological properties, i ..."
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Cited by 30 (3 self)
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[1] Vegetation affects the climate by modifying the energy, momentum, and hydrologic balance of the land surface. Soil-vegetation-atmosphere transfer (SVAT) schemes explicitly consider the role of vegetation in affecting water and energy balance by taking into account its physiological properties, in particular, leaf area index (LAI) and stomatal conductance. These two physiological properties are also the basis of evapotranspiration parameterizations in physically based hydrological models. However, most current SVAT schemes and hydrological models do not parameterize vegetation as a dynamic component. The seasonal evolution of LAI is prescribed, and monthly LAI values are kept constant year after year. The effect of CO 2 on the structure and physiological properties of vegetation is also neglected, which is likely to be important in transient climate simulations with increasing CO 2 concentration and for hydrological models that are used to study climate change impact. The net carbon uptake by vegetation, which is the difference between photosynthesis and respiration, is allocated to leaves, stems, and roots. Carbon allocation to leaves determines their biomass and LAI. The timing of bud burst, leaf senescence, and leaf abscission (i.e., the phenology) determines the length of the grow-1.
2004), RHESSys: Regional Hydro-Ecologic Simulation System—An object-oriented approach to spatially distributed modeling of carbon, water, and nutrient cycling
- Earth Interact
"... ABSTRACT: Process-based models that can represent multiple and interacting processes provide a framework for combining field-based measure-ments with evolving science-based models of specific hydroecological processes. Use of these models, however, requires that the representation of processes and k ..."
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Cited by 30 (4 self)
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ABSTRACT: Process-based models that can represent multiple and interacting processes provide a framework for combining field-based measure-ments with evolving science-based models of specific hydroecological processes. Use of these models, however, requires that the representation of processes and key assumptions involved be understood by the user community. This paper provides a full description of process implementation in the most recent version of the Regional Hydro-Ecological Simulation System (RHESSys), a model that has been applied in a wide variety of research
Growth and yield models for uneven-aged stands: past, present and future. Forest Ecology and Management 2000;132:259–79
"... Growth and yield modeling has a long history in forestry. Methods of measuring the growth of uneven-aged forest stands have evolved from those developed in France and Switzerland during the last century. Furthermore, uneven-aged growth and yield modeling has progressed rapidly since the first models ..."
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Cited by 26 (1 self)
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Growth and yield modeling has a long history in forestry. Methods of measuring the growth of uneven-aged forest stands have evolved from those developed in France and Switzerland during the last century. Furthermore, uneven-aged growth and yield modeling has progressed rapidly since the first models were pioneered by Moser and Hall (1969) (Moser Jr., J.W., Hall, O.F., 1969. For. Sci. 15, 183–188). Over the years, a variety of models have been developed for predicting the growth and yield of uneven-aged stands using both individual and stand-level approaches. Modeling methodology not only has moved from an empirical approach to a more ecological process-based mechanistic approach, but also has incorporated a variety of techniques, such as, (1) systems of equations, (2) nonlinear stand table projections, (3) Markov chains, (4) matrix models, and (5) artificial neural network models. However, modeling the growth and yield of uneven-aged stands has received much less attention than that of even-aged stands. This paper reviews the current literature regarding growth and yield models for uneven-aged stands, discusses basic types of models and their merits, and reports recent progress in modeling the growth and dynamics of uneven-aged stands. Furthermore, future trends involving integration of new computer technologies (object-oriented programming and user-friendly interfaces), tree visualization techniques, and the spatially explicit application of Geographical Information Systems (GIS) into uneven-aged modeling strategies are discussed. # 2000 Elsevier Science B.V.
A model comparison for daylength as a function of latitude and day of the year.
- Ecological Modeling
, 1995
"... Abstract A model that calculates the length of the day for a flat surface for a given latitude and day of the year is described. Calculated daylengths are within 1 minute of values published in Smithsonian Meteorological Tables and the Astronomical Almanac for latitudes between 40 ° North and South ..."
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Cited by 26 (0 self)
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Abstract A model that calculates the length of the day for a flat surface for a given latitude and day of the year is described. Calculated daylengths are within 1 minute of values published in Smithsonian Meteorological Tables and the Astronomical Almanac for latitudes between 40 ° North and South with a maximum error of 7 minutes occurring at 60 ° latitude. The model allows the use of different definitions of sunrise/sunset and the incorporation of twilight. Comparisons with other daylength models indicate that this model is more accurate and that variation in accumulated hours of daylight of up to one week over the course of the growing season can be accounted for by how sunrise/sunset are defined.
Analysis and optimization of the MODIS Leaf Area Index algorithm retrievals over broadleaf forests
- IEEE Trans. Geosci. Remote Sens
, 2005
"... Abstract—Broadleaf forest is a major type of Earth’s land cover with the highest observable vegetation density. Retrievals of biophysical parameters, such as leaf area index (LAI), of broadleaf forests at global scale constitute a major challenge to modern remote sensing techniques in view of low se ..."
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Cited by 25 (6 self)
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Abstract—Broadleaf forest is a major type of Earth’s land cover with the highest observable vegetation density. Retrievals of biophysical parameters, such as leaf area index (LAI), of broadleaf forests at global scale constitute a major challenge to modern remote sensing techniques in view of low sensitivity (saturation) of surface reflectances to such parameters over dense vegetation. The goal of the performed research is to demonstrate physical principles of LAI retrievals over broadleaf forests with the Moderate Resolution Imaging Spectroradiometer (MODIS) LAI algorithm and to establish a basis for algorithm refinement. To sample natural variability in biophysical parameters of broadleaf forests, we selected MODIS data subsets covering deciduous broadleaf forests of the eastern part of North America and evergreen broadleaf forests of Amazonia. The analysis of an annual course of the Terra MODIS Collection 4 LAI product over broadleaf
BIOMEBGC simulations of stand hydrologic processes for
- 102(D24): 29 043
, 1997
"... Abstract. BIOME-BGC is a general ecosystem model designed to simulate hydrologic and biogeochemical processes across multiple scales. The objectives of this investigation were to compare BIOME-BGC estimates of hydrologic processes with observed data for different boreal forest stands and investigate ..."
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Cited by 20 (1 self)
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Abstract. BIOME-BGC is a general ecosystem model designed to simulate hydrologic and biogeochemical processes across multiple scales. The objectives of this investigation were to compare BIOME-BGC estimates of hydrologic processes with observed data for different boreal forest stands and investigate factors that control simulated water fluxes. Model Iesults explained 62 and 98 % of the respective variances in observed daily evapotranspiration and soil water; simulations of the onset of spring thaw and.the dates of snowpack disappearance and accumulation also generally tracked observations. Differences between o6served and simulated evapotranspiration were attributed to model assumptions of constant, growing season, overstory leaf areas that did not account for phenological changes and understory effects on stand daily water fluxes. Vapor pressure deficit and solar radiation accounted for 58-74 % of the variances in simulated daily evapotranspiration during the growing season, though low air temperature and photosynthetic light levels were found to be the inajor limiting factors regulating simulated canopy conductances to water vapor. Humidity and soil moisture were generally not low enough to induce physiological wat~r stress in black spruce stands, though low soil water
