Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 34 for “"Land Surface Model"”.
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Estimation of the global carbon fluxes due to agricultural management activities using a land surface model (ISAM)
… from the agriculture sector. This study uses a land surface model with spatially heterogeneous representations of agricultural land management practices to estimate the carbon dynamics induced by agricultural land management practices (i.e., planting crops, fertilization, irrigation, harvesting, …
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Impacts of model-data uncertainties on biogeophysical-biogeochemical interactions in a land surface model (with an emphasis on the northern high-latitude regions)
… investigated the impacts of current model-data uncertainties on biogeophysical-biogeochemical interactions in a terrestrial modeling framework. To achieve this objective, I applied a land surface model, specifically the Integrated Science Assessment Model (ISAM), at spatial scales …
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Snow Hydrology and Streamflow Response to Snowmelt: A Case Study on SWE Dataset Comparisons, Regional Water Balance, and Snowmelt-Induced Runoff within the Smith River Watershed, Montana
… WUS-SR, SNODAS, and Noah-MP via WLDAS) and SnowModel were validated against observations from five Snow Telemetry (SNOTEL) stations using correlation (r), mean absolute error (MAE), and root mean square error (RMSE). Models assimilating SNOTEL data (SNODAS, UA 800m, and UA 4km) performed best. …
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Estimating Soil Moisture and Energy Fluxes Using Assimilation of Remotely Sensed Land Surface State Variables
Soil moisture plays a critical role in the land-atmosphere interactions. Given the approximate model physics representation in the land surface models predicting these fluxes, better predictions can be obtained by assimilating hydrologically relevant remotely sensed data into the predictive models. …
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Soil moisture dynamics from satellite observations, land surface modeling, and field data
… The simple physical soil moisture dynamics model was identified as an alternative approach to characterize statistical soil moisture variability. The soil moisture variability was strongly related to physical properties including rainfall and topography.</p><p>Normal and log-normal …
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Hydrologic sensitivities of western U.S. rivers to climate change
… of this information in water management. Using land surface model simulations, I explore the sensitivity of runoff to changes in precipitation (defined as precipitation elasticities, E, the fractional change in runoff divided by the fractional change in precipitation), changes in temperature …
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Quantifying terrestrial ecosystem carbon dynamics with mechanistically-based biogeochemistry models and in situ and remotely sensed data
… approach, mechanistically-based biogeochemistry models and in situ and remotely sensed data.</p> <p>The upscaling studies based on FLUXNET network has provided us the spatial and temporal pattern of the carbon fluxes but it fails to consider the atmospheric CO2 effect given its important …
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Quantifying biophysical and biogeochemical influence on northern high latitudes greenhouse gases dynamics
… gases (GHGs) emission in a terrestrial modeling framework. To achieve this objective, I extended and calibrated a land surface model, the Integrated Science Assessment Model (ISAM), to explore how the physical and chemical interactions within the atmosphere-land-soil continuum determined …
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A joint analysis of gross primary production and evapotranspiration of Australia using eddy covariance, remote sensing and land surface modelling approaches
… of eddy covariance, remote sensing and land surface model (LSM) methods, taking advantage of their respective applicability on different space and time scales. To do this, I (1) used the wavelet method to decompose eddy covariance observed half-hourly GPP and ET into different …
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Hydrologic data assimilation of multi-resolution microwave radiometer and radar measurements using ensemble smoothing
… forecasts from a conventional though uncertain land surface model (LSM). Here it is argued that soil moisture estimation is a reanalysis-type problem and thus smoothingis more appropriate than filtering. An ensemble moving batch smoother, an extension of the EnKF in which the state vector is …
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Study of the atmospheric boundary layer processes over sloping terrain covered by sparse canopy
… over complex terrain morphology, varying surface roughness, and a wide range of atmospheric thermal conditions. The surface roughness object of the research is a sparse canopy layer evolving in time along the vegetative season, and characterized by a multiplicity of temporal and spatial …
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Evaluating Changes in Terrestrial Hydrological Components Due to Climate Change in the Chesapeake Bay Watershed
… region of the United States. The Noah-MP land surface model is calibrated and evaluated against the observed datasets of United States Geological Survey (USGS) streamflow gages, actual evapotranspiration from USGS Simplified Surface Energy Balance (SSEBop) Model and soil moisture from Soil …
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Multi-Level Factorial Sensitivity Analysis of REGCM4 Physical Scheme Combinations Over Canada
… Moreover, the PBL scheme, moisture scheme and land surface model are found to be the dominant factors of temperature, precipitation and wind speed simulations, respectively. Furthermore, the vegetation cover conditions may affect the cumulus convective activities to some extent, accounting for …
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Modeling of N2O emission from unmanaged terrestrial ecosystem soils
… of soils. In this study, I employ a land surface model, the Integrated Science Assessment Model (ISAM), to model the global N2O emissions from terrestrial ecosystem soils. The model is calibrated and evaluated with field measurements of N2O from different sites with different biome …
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Soil Moisture Dynamics and Thresholds for Surface Energy Balance Regime Transitions: An Observational Analysis at a U.S. Grassland Site
… critical for assessing plant water stress, surface energy partitioning, and land–atmosphere interactions. These periods of moisture loss, commonly referred to as soil moisture drydowns, provide a valuable window into the transition from wet to dry surface conditions. This study focuses on …
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Intercomparison of soil hydrology modules in the MIT Integrated Global System Model for analysis of climate issues
The availability of water at or near the surface determines the way incident radiative energy is partitioned at the ground surface. The goal of this thesis is to determine if better hydrological representation in the MIT Integrated Global System Model will improve its climate prediction capability. …
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Biosphere-atmosphere interaction in a one-dimensional climate model of the tropics
In this study, we develop a one-dimensional model of the tropics which includes two way interaction between the biosphere and the atmosphere. The model integrates a radiative-convective equilibrium model of the atmosphere, a land surface model including plant growth and competition and a monsoon …
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Data assimilation and dynamical downscaling of remotely-sensed precipitation and soil moisture from space
… invaluable information for understanding the land-atmosphere water and energy exchanges. However, the use of satellite observations in hydrologic applications is often limited by coarse space-time resolutions. This study aims to develop a data assimilation system that integrates …
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From groundwater to the atmosphere: using RELAMPAGO observations and modeling to understand changes in the hydrologic cycle of southeastern South America
Land-atmosphere interactions play an important role in modulating the hydroclimate of Southeastern South America (SESA). While climate variability and extreme events impact surface hydrology, the land surface of the region influences evapotranspiration, groundwater table depth, near-surface soil …
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Multi-scale Remote Assessment of Phenology of Photosynthesis and Productivity of Northern Forests
… I parameterized a light-use efficiency (LUE) model with PRI and CCI as proxies of ɛ and compared model performance with a meteorological-based LUE model and a land surface model. The PRI- and CCI-LUE models demonstrated improved performance for reflecting the timing of phenology of GPP. …
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