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Improving Estimation Of Gross Primary Productivity Of Terrestrial Ecosystems, Qingyuan Zhang
Improving Estimation Of Gross Primary Productivity Of Terrestrial Ecosystems, Qingyuan Zhang
Doctoral Dissertations
The MOderate Resolution Imaging Spectroradiometer (MODIS) provides an unprecedented opportunity to monitor and quantify seasonal changes of vegetation and phenology. MODIS has the potential to improve the estimation, which is based on the algorithms for the NOAA Advanced Very High Resolution Radiometer (AVHRR), of biophysical/biochemical variables of vegetation. My doctoral study improves estimation of gross primary productivity (GPP) through two aspects: first, my study improved the detection of vegetation phenology by distinguishing MODIS contaminated observations and contamination-free observations, and secondly, I inverted the fraction of absorbed photosynthetically active radiation (PAR) by chlorophyll using radiative transfer models and daily MODIS data. …
Recent Extreme Events In A Tropical Stalagmite: Multi-Proxy Records And Analysis Of Ecosystem Delta Carbon-13 Value Sensitivity To Weak Climate Forcing, Amy E Benoit Frappier
Recent Extreme Events In A Tropical Stalagmite: Multi-Proxy Records And Analysis Of Ecosystem Delta Carbon-13 Value Sensitivity To Weak Climate Forcing, Amy E Benoit Frappier
Doctoral Dissertations
Speleothems are emerging as important and detailed chronological records of environmental change. Integrating exploration of modern speleothem records of environmental variability, related forcing factors, and understanding and suggests new potential proxies. This dissertation demonstrates the potential for developing novel proxy records of past regional environmental extremes, such as tropical cyclones, explosive volcanism, and enhanced seasonal contrasts from speleothems that are sensitive to transient infiltration events through very high-resolution, multi-parameter analysis of a rapidly growing, fracture-fed tropical stalagmite. A series of sample screening steps were developed prior to stalagmite collection in the field in order to increase the likelihood of collecting …
Tropical Forest Structure: Ground Measurements Of Coarse Necromass And Satellite Observations Of Crown Geometry, Michael W. Palace
Tropical Forest Structure: Ground Measurements Of Coarse Necromass And Satellite Observations Of Crown Geometry, Michael W. Palace
Doctoral Dissertations
Forests are structurally diverse, but these structures derive from the same processes of disturbance and growth. Understanding forest structure can help unlock the history, function, and future of a forested ecosystem. Components of forest structure include tree size distributions, foliage distributions and variation in canopy density, and coarse woody debris (coarse necromass). Tropical rainforests are structurally the most complex of all ecosystems. In addition to having high biological diversity, Amazon forests are marked by complex vegetation dynamics and a diverse forest stand structures, which play an important role in the interactions of water and carbon between the biosphere and atmosphere. …
Non-Reactive Gas Dynamics In The Piscataqua Estuary Inlet, Takashi Kalani Brown
Non-Reactive Gas Dynamics In The Piscataqua Estuary Inlet, Takashi Kalani Brown
Master's Theses and Capstones
For 135 days, from late autumn 2005 to the mid---spring 2006, continuous measurements of dissolved nitrogen, oxygen, and carbon dioxide in near surface seawater were recorded at the interface between the Great Bay-Piscataqua Estuary and the western Gulf of Maine. These surface measurements were made to investigate air-sea gas fluxes and identify the primary controls over gas dynamics in a macrotidal estuary entryway, the estuary inlet. Wind-parameterized air-sea flux estimations were calculated using published flux models and were evaluated to determine their appropriateness in the estuary inlet. Also, using supporting sea-state measurements from buoys (wind speed and wave height), the …
Abiotic Retention Of Nitrogen And Dissolved Organic Matter By Forest Mineral Soils, Naoko Watanabe
Abiotic Retention Of Nitrogen And Dissolved Organic Matter By Forest Mineral Soils, Naoko Watanabe
Master's Theses and Capstones
The effect of NO3- deposition on NH4 +, DON, and DOC retention as well as abiotic NO3 - retention via the hypothesized "ferrous wheel" mechanism was examined in oxic and anoxic tropical and oxic temperate soils using sorption isotherm experiments. Adsorption of NH4+, DON, and DOC by mineral soils was examined in forest floor extracts with DOC levels of 0-50 mg/L. Experimental treatments included no added NO3-, 4mg/L of added NO3-, or 4 mg/L of NO3 - and 2 mg/L of Fe3+. Ferric iron was added since it would likely increase DOC retention in the context of podzolization, and it …