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Assessment Of Skill And Portability In Regional Marine Biogeochemical Models: Role Of Multiple Planktonic Groups, Marjorie A. M. Friedrichs, Jeffery A. Dusenberry, Laurence A. Anderson, Robert A. Armstrong, Fei Chai, James R. Christian, Scott C. Doney, John Dunne, Masahiko Fujii, Jerry D. Wiggert Jan 2007

Assessment Of Skill And Portability In Regional Marine Biogeochemical Models: Role Of Multiple Planktonic Groups, Marjorie A. M. Friedrichs, Jeffery A. Dusenberry, Laurence A. Anderson, Robert A. Armstrong, Fei Chai, James R. Christian, Scott C. Doney, John Dunne, Masahiko Fujii, Jerry D. Wiggert

CCPO Publications

[1] Application of biogeochemical models to the study of marine ecosystems is pervasive, yet objective quantification of these models' performance is rare. Here, 12 lower trophic level models of varying complexity are objectively assessed in two distinct regions (equatorial Pacific and Arabian Sea). Each model was run within an identical one-dimensional physical framework. A consistent variational adjoint implementation assimilating chlorophyll-a, nitrate, export, and primary productivity was applied and the same metrics were used to assess model skill. Experiments were performed in which data were assimilated from each site individually and from both sites simultaneously. A cross-validation experiment was also conducted …

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Impact Of Anthropogenic Combustion Emissions On The Fractional Solubility Of Aeroosol Iron: Evidence From The Sargasso Sea, Peter N. Sedwick, Edward R. Sholkovitz, Thomas M. Church Jan 2007

Impact Of Anthropogenic Combustion Emissions On The Fractional Solubility Of Aeroosol Iron: Evidence From The Sargasso Sea, Peter N. Sedwick, Edward R. Sholkovitz, Thomas M. Church

OES Faculty Publications

We report empirical estimates of the fractional solubility of aerosol iron over the Sargasso Sea during periods characterized by high concentrations of Saharan dust (summer 2003) and by low concentrations of aerosols in North American/maritime North Atlantic air masses (spring 2004 and early summer 2004). We observed a strong inverse relationship between the operational solubility of aerosol iron (defined using a flow-through deionized-water leaching protocol) and the total concentration of aerosol iron, whereby the operational solubility of aerosol iron was elevated when total aerosol iron loadings were low. This relationship is consistent with source-dependent differences in the solubility characteristics of …

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Chemical Analyses In Support Of Yucca Mountain Studies, Harry Reid Center For Environmental Studies, University Of Nevada, Las Vegas Jan 2007

Chemical Analyses In Support Of Yucca Mountain Studies, Harry Reid Center For Environmental Studies, University Of Nevada, Las Vegas

Publications (YM)

Research Objectives: Provide preparation of injectates, sorption studies and analyses for tracer tests Provide REE, trace metals, majors and field measurement data from wells of the Nye County Early Warning Drilling Program (NCEWDP)and Inyo County Other laboratory needs as they arise

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Nutrient Concentrations At Baseflow Conditions In The Upper White River Basin, Southwest Missouri And Northwest Arkansas, Gopala G. Borchelt Jan 2007

Nutrient Concentrations At Baseflow Conditions In The Upper White River Basin, Southwest Missouri And Northwest Arkansas, Gopala G. Borchelt

Graduate Theses/Dissertations

The Upper White River Basin (UWRB) is becoming increasingly vulnerable to water quality degradation from urban/population growth and increased agricultural production. This study examines the relationships among nutrient levels, water chemistry and watershed characteristics of 19 watersheds in the UWRB. Water samples were collected during baseflow conditions each month for one year at USGS continuous-flow gage stations. Watershed characteristics evaluated were land use, geology, drainage area, flow discharge, and wastewater treatment plant discharge (WTP). Measured chemical water quality indicators include total nitrogen (TN), total phosphorus (TP), specific conductivity, turbidity, pH and dissolved oxygen. Rapidly expanding urban areas are associated with …

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Environmental Impact And Drainage Geochemistry In The Vicinity Of The Harput Pb-Zn-Cu Veins, Elazığ, Se Turkey, Leyla Kalender, Cemal Bölücek Jan 2007

Environmental Impact And Drainage Geochemistry In The Vicinity Of The Harput Pb-Zn-Cu Veins, Elazığ, Se Turkey, Leyla Kalender, Cemal Bölücek

Turkish Journal of Earth Sciences

The aim of this study was to examine the environmental impact of major, minor and rare-earth elements (REE) in spring waters and major and minor elements in stream sediments proximal to known vein-type Pb-Zn-Cu ores. Accordingly, a total of 21 water samples were collected from natural springs in the Köprücük, Çolaklı, Kabakçılar and Ekinli areas where ore-bearing rocks are widely exposed. Stream-sediment samples were taken from the Kurt, Kızıldağ and Karacalar and Billurik streams, and a total of 57 samples were sieved to three different size fractions (-80 +140, -140 +200 and -200 mesh) and analyzed by ICP-MS and IE …

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The Dikili-Çandarlı Volcanics, Western Turkey: Magmatic Interactions As Recorded By Petrographic And Geochemical Features, Zeki̇ye Karacik, Yücel Yilmaz, Julian A. Pearce Jan 2007

The Dikili-Çandarlı Volcanics, Western Turkey: Magmatic Interactions As Recorded By Petrographic And Geochemical Features, Zeki̇ye Karacik, Yücel Yilmaz, Julian A. Pearce

Turkish Journal of Earth Sciences

Located in the northwestern part of the Aegean region, Dikili-Çandarlı volcanic suite contains products representative for the western Anatolian Miocene volcanism. They can be divided into two main groups: the Dikili and the Çandarlı groups. The Dikili group is Early-Middle Miocene in age and consists mainly of pyroclastic rocks, andesitic-dacitic lavas, lava breccia, lahar flows and associated sedimentary rocks. The lavas contain disequilibrium phenocrysts assemblages. The Çandarlı group consists of Upper Miocene-Pliocene lava and sediment associations. The volcanic rocks consist mainly of rhyolitic domes and basaltic trachyandesite-basaltic andesite lavas erupted along the NW-SE- and NE-SW-trending fault systems; the faults controlled …

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Jurassic Volcanism In The Eastern Pontides: Is It Rift Related Or Subduction Related?, Cüneyt Şen Jan 2007

Jurassic Volcanism In The Eastern Pontides: Is It Rift Related Or Subduction Related?, Cüneyt Şen

Turkish Journal of Earth Sciences

The Jurassic volcanic rocks in the centre of the northern zone (south of Trabzon City) provide important constraints on the evolution of Pontides. The investigated volcanic rocks form a transitional series between tholeiitic and calc-alkaline, and is dominated by basalt, basaltic andesite and andesite. Geochemically, they are enriched in LILE and LREE contents and depleted in HFSE [(La/Yb)_N= 2.2 - 8.5; (Nb/La)_N= 0.1 - 0.77)] compared to mid-ocean ridge basalts and have radiogenic Nd isotope ratios of \epsilonNd(210 Ma)= -0.72 to 3.24. These trace element and isotope data suggest that these rocks were derived from low degrees of partial melting …

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Quartz Grain Surface Textures As Indicators Of Infilling Processes And Depositional Environments Associated With Ice-Wedge Casts In Northeast Iowa, Michael Loux Jan 2007

Quartz Grain Surface Textures As Indicators Of Infilling Processes And Depositional Environments Associated With Ice-Wedge Casts In Northeast Iowa, Michael Loux

Honors Program Theses

Ice-wedge casts and polygonal patterned ground are common features of the Iowan Surface of Northeast Iowa. Paleoenvironmental studies in Iowa and adjacent states indicate that tundra conditions existed in Northeast Iowa between 21,000 and 16,500 years BP, the coldest part of late \\'.'isconsinan time. Degradation of permafrost and formation of ice-wedge casts must have occurred near the end of this cold climate episode, which also promoted extreme erosion of the landscape in Northeast Iowa. The sediment-filled wedges in Northeast Iowa occur in pre-Illinoian till with the infilling material consisting mostly of sand. The details of the infilling history of the …

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Burrows Dug By Large Vertebrates Into Rain-Moistened Middle Jurassic Sand Dunes: A Reply, David B. Loope Jan 2007

Burrows Dug By Large Vertebrates Into Rain-Moistened Middle Jurassic Sand Dunes: A Reply, David B. Loope

Department of Earth and Atmospheric Sciences: Faculty Publications

Odier (2007) is concerned with two issues: (1) I did not cite his work on burrows in the Navajo Sandstones of southeastern Utah in my article (Loope 2006), and (2) he believes I amwrong in interpreting the structures preserved in the Entrada Sandstone as burrows. On the first issue, I failed to cite both his 2004 abstract and the newly published book that he sent me in October 2006. My article was accepted on June 12, 2006; I returned the proofs on August 23; and the issue was published online on October 4, 2006. The timing of these events makes …

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The Sensitivity Of Convective Initiation To The Lapse Rate Of The Active Cloud-Bearing Layer, Adam L. Houston, Dev Niyogi Jan 2007

The Sensitivity Of Convective Initiation To The Lapse Rate Of The Active Cloud-Bearing Layer, Adam L. Houston, Dev Niyogi

Department of Earth and Atmospheric Sciences: Faculty Publications

Numerical experiments are conducted using an idealized cloud-resolving model to explore the sensitivity of deep convective initiation (DCI) to the lapse rate of the active cloud-bearing layer [ACBL; the atmospheric layer above the level of free convection (LFC)]. Clouds are initiated using a new technique that involves a preexisting airmass boundary initialized such that the (unrealistic) adjustment of the model state variables to the imposed boundary is disassociated from the simulation of convection. Reference state environments used in the experiment suite have identical mixed layer values of convective inhibition, CAPE, and LFC as well as identical profiles of relative humidity …

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Observational Analysis Of The 27 May 1997 Central Texas Tornadic Event. Part Ii: Tornadoes, Adam L. Houston, Robert B. Wilhelmson Jan 2007

Observational Analysis Of The 27 May 1997 Central Texas Tornadic Event. Part Ii: Tornadoes, Adam L. Houston, Robert B. Wilhelmson

Department of Earth and Atmospheric Sciences: Faculty Publications

The 27 May 1997 central Texas tornadic event has been investigated in a two-part observational study. As demonstrated in Part I, the 1D environment associated with this event was unfavorable for significant (≥F2) tornadoes. Yet, the storm complex produced at least six significant tornadoes, including one rated F5 (the Jarrell, Texas, tornado). The purpose of this article is to examine the spatiotemporal interrelationships between tornadoes, preexisting boundaries, antecedent low-level mesocyclones, convective cells, and midlevel mesocyclones. It is shown that each of the six observed tornadoes that produced greater than F0 damage formed along the storm-generated gust front, not along preexisting …

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Observational Analysis Of The 27 May 1997 Central Texas Tornadic Event. Part I: Prestorm Environment And Storm Maintenance/Propagation, Adam L. Houston, Robert B. Wilhelmson Jan 2007

Observational Analysis Of The 27 May 1997 Central Texas Tornadic Event. Part I: Prestorm Environment And Storm Maintenance/Propagation, Adam L. Houston, Robert B. Wilhelmson

Department of Earth and Atmospheric Sciences: Faculty Publications

A detailed analysis of the 27 May 1997 central Texas tornadic storm complex is undertaken in an attempt to document the prestorm environment and identify the roles played by preexisting boundaries on storm maintenance/propagation and rotation. Analysis is carried out using a broad suite of synoptic and subsynoptic data but focuses on the level-II and -III Weather Surveillance Radar-1988 Doppler (WSR-88D) data from three Texas radars. The 27 May 1997 event was characterized by a back-building (propagation against the mean flow) storm complex that produced at least 12 tornadoes including the F5 Jarrell, Texas, tornado. Furthermore, five of the eight …

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Simulations Of Phytoplankton Species And Carbon Production In The Equatorial Pacific Ocean 2. Effects Of Physical And Biogeochemical Processes, Baris Salihoglu, Eileen E. Hofmann Jan 2007

Simulations Of Phytoplankton Species And Carbon Production In The Equatorial Pacific Ocean 2. Effects Of Physical And Biogeochemical Processes, Baris Salihoglu, Eileen E. Hofmann

CCPO Publications

A one-dimensional multi-component lower trophic level ecosystem model that includes detailed algal physiology is used to investigate the response of phytoplankton community and carbon production and export to variations in physical and biochemical processes in the Cold Tongue region of the equatorial Pacific Ocean at ON, 140W. Results show that high-frequency variability in vertical advection and temperature is an important mechanism driving the carbon export. Filtering out low frequency physical forcing results in a 30% increase in primary production and dominance of high-light adapted Prochlorococcus and autotrophic eukaryotes. Sensitivity studies show that iron availability is the primary control on carbon …

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Late Cretaceous To Paleocene Metamorphism And Magmatism In The Funeral Mountains Metamorphic Core Complex, Death Valley, California, Chris G. Mattinson, Joseph P. Colgan, James R. Metcalf, Elizabeth L. Miller, Joseph L. Wooden Jan 2007

Late Cretaceous To Paleocene Metamorphism And Magmatism In The Funeral Mountains Metamorphic Core Complex, Death Valley, California, Chris G. Mattinson, Joseph P. Colgan, James R. Metcalf, Elizabeth L. Miller, Joseph L. Wooden

All Faculty Scholarship for the College of the Sciences

Amphibolite-facies Proterozoic metasedimentary rocks below the low-angle Cenozoic Boundary Canyon Detachment record deep crustal processes related to Mesozoic crustal thickening and subsequent extension. A 91.5 ± 1.4 Ma Th-Pb SHRIMP-RG (sensitive high-resolution ion microprobe–reverse geometry) monazite age from garnet-kyanite-staurolite schist constrains the age of prograde metamorphism in the lower plate. Between the Boundary Canyon Detachment and the structurally deeper, subparallel Monarch Spring fault, prograde metamorphic fabrics are overprinted by a pervasive greenschist-facies retrogression, high-strain subhorizontal mylonitic foliation, and a prominent WNW-ESE stretching lineation parallel to corrugations on the Boundary Canyon Detachment. Granitic pegmatite dikes are deformed, rotated into parallelism, and …

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Evolution Of An Allochthonous Salt System, Southern Mars-Ursa Basin, Northern Gulf Of Mexico, Angela Bordelon Pell Jan 2007

Evolution Of An Allochthonous Salt System, Southern Mars-Ursa Basin, Northern Gulf Of Mexico, Angela Bordelon Pell

LSU Master's Theses

This study examines the evolution of an allochthonous salt system in the southern Mars-Ursa basin. A seismic stratigraphic framework and biostratigraphic markers provided constraints on basin development and sediment accumulation from late Miocene to middle Pliocene time. External geometries of tectonostratigraphic packages are identified in the study area and are combined with analyses of brittle deformation to track salt evacuation in the study area. External geometries identified in the study include: wedge, layer and trough. Fifty-nine faults were mapped in basin and suprasalt strata and five phases of brittle deformation were identified. Eight evolutionary stages were identified for the time …

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Ichnogenic Porosity, High-Frequency Cyclostratigraphy, And Groundwater Flow In The Karst Biscayne Aquifer, Se Florida, Usa, Kevin Cunningham, H. Allen Curran Jan 2007

Ichnogenic Porosity, High-Frequency Cyclostratigraphy, And Groundwater Flow In The Karst Biscayne Aquifer, Se Florida, Usa, Kevin Cunningham, H. Allen Curran

Geosciences: Faculty Publications

No abstract provided.

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Heavy Mineral Analysis Of The Pecan Island Complex, Louisiana Chenier Plain, Southwest Louisiana, Cherie' Jenae Lee Jan 2007

Heavy Mineral Analysis Of The Pecan Island Complex, Louisiana Chenier Plain, Southwest Louisiana, Cherie' Jenae Lee

LSU Master's Theses

This study reports the results of a heavy mineral analysis of samples from Pecan Island and associated ridges on the Louisiana Chenier Plain. The goal of the study is to provide additional insight on the origins of the sand comprising the ridges. Chenier plains are multi-membered, progradational ridge-interridge mudflat sequences (Augustinus, 1989). The various suggested sources of the sand grains include: the Mississippi River, especially the Teche sub-delta; the Mermentau and Calcasieu Rivers; and the reworking of older mudflat and chenier ridges. Several liters of sand were collected from a depth of 0.5 to 2.0 meters at locations near the …

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Seismic Constraints On Slow Slip Events Within The Cascadia Subduction Zone, Ana Cristina Aguiar Jan 2007

Seismic Constraints On Slow Slip Events Within The Cascadia Subduction Zone, Ana Cristina Aguiar

All Master's Theses

Reanalysis of geodetic GPS time series from the Cascadia subduction zone have revealed at least 30 resolvable slow slip events along the megathrust, ranging from northern California to southern British Columbia, since 1997. Many of the smaller and more recent events are barely resolvable with GPS, but stand out clearly as tremor sequences. Since tremor bursts lasting less than 10-seconds are often visible across multiple stations, they offer the highest resolution for studying moment release through time. To test the hypothesis that tremor and transient deformation are two manifestations of the same faulting process, and to quantify the relative contribution …

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Paleoflood Record Reconstruction At An Archaeological Site On The Owyhee River, Southeastern Oregon, Stephanie Louise Vandal Jan 2007

Paleoflood Record Reconstruction At An Archaeological Site On The Owyhee River, Southeastern Oregon, Stephanie Louise Vandal

All Master's Theses

The magnitude and frequency of late Holocene floods on the Owyhee River in southeastern Oregon were reconstructed from fine-grained flood deposits at three sites in the river canyon. The stratigraphy at the Birch Creek study site (BCSS) preserves a record of seven to nine large floods from the last 2800 years. Two additional study sites, the Iron Gate and Waterwheel, within a 5-km reach of the BCSS, showed 18-26 floods from the late Holocene to 1993 A.D. and 17-22 floods from 8600 B.P. to 1993 A.D., respectively. Hydrologic Engineering Center-River Analysis System modeling of the 1993 flood and several paleofloods …

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High- And Ultrahigh-Pressure Metamorphism In The North Qaidam And South Altyn Terranes, Western China, Chris G. Mattinson, C. A. Menold, Jian-Xin Zhang, D. K. Bird Jan 2007

High- And Ultrahigh-Pressure Metamorphism In The North Qaidam And South Altyn Terranes, Western China, Chris G. Mattinson, C. A. Menold, Jian-Xin Zhang, D. K. Bird

All Faculty Scholarship for the College of the Sciences

The North Qaidam and South Altyn terranes extend approximately 1000 km across the northern Tibetan Plateau, and five localities preserve evidence of Early Paleozoic high-pressure (HP) or ultrahigh-pressure (UHP) metamorphism, including the presence of coesite, coesite pseudomorphs, and diamond. A review of the geology, petrology, and geochronology collected over the past 10 years since these localities were discovered supports a correlation of the North Qaidam and South Altyn terranes, offset 350-400 km across the Altyn Tagh fault. Geochronology interpreted to reflect eclogite-facies metamorphism yields ages between 500 and 420 Ma; detailed geochronology from one locality supports a protracted (tens of …

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Late Holocene Uplift Of The Chihshang Segment Of The Longitudinal Valley Fault At Fuli, Eastern Taiwan, Brian Thomas Gray Jan 2007

Late Holocene Uplift Of The Chihshang Segment Of The Longitudinal Valley Fault At Fuli, Eastern Taiwan, Brian Thomas Gray

All Master's Theses

Uplifted Holocene strath terraces of the Bieh River drainage, eastern Taiwan, were analyzed in order to determine millennial-scale uplift and horizontal shortening rates of the Longitudinal Valley fault. Detrital charcoal fragments collected from three terraces within the Bieh River drainage yield ages between 1395 and 555 cal. yr B.P, suggesting an average uplift rate of 11.3 ± 3.6 mm yr-1 for the last 1400 cal. yr B.P. The average horizontal shortening rate of 19.7 ± 9.5 mm yr-1 was within error of present-day conventional geodetic measurements, but near the lower limit of the geodetic measurements. This suggests that …

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Paleosalinity History Of Middle Holocene Lagoonal And Lacustrine Deposits In The Enriquillo Valley, Dominican Republic Based On Pore Morphometrics And Isotope Geochemistry Of Ostracoda, Pamela Medley, Neil E. Tibert, William P. Patterson, H. Allen Curran, Lisa Greer, Jean-Paul Colin Jan 2007

Paleosalinity History Of Middle Holocene Lagoonal And Lacustrine Deposits In The Enriquillo Valley, Dominican Republic Based On Pore Morphometrics And Isotope Geochemistry Of Ostracoda, Pamela Medley, Neil E. Tibert, William P. Patterson, H. Allen Curran, Lisa Greer, Jean-Paul Colin

Geosciences: Faculty Publications

The southwestern region of the Dominican Republic (Enriquillo Valley) contains exceptionally well-preserved, relict marine and saline lake deposits of mid-Holocne age. Abundant euryhaline ostracodes found in this deposit include Cyprideis salebrosa, C. mexicana, C. similis, and C. edentata. Morphometric and geochemical analyses performed on Cyprideis spp. provide high δ18O and δ13C values that are coincident with relative abundances of irregularly shaped pores that permeate the ostracode carapace. We recognize three stratigraphic intervals with distinct ostracode pore shape and stable isotope trends: (I) a 4.5-5.0m interval that contains ostracodes with highly irregular shaped pores (multiradiate) and …

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Farm Water For The North-Eastern And Eastern Wheatbelt Of Western Australia (Zones 2 And 5), Susan Murphy-White Jan 2007

Farm Water For The North-Eastern And Eastern Wheatbelt Of Western Australia (Zones 2 And 5), Susan Murphy-White

Resource management technical reports

Large proportions of Western Australia's dryland farms suffer from water supply problems in the form of shortages, poor quality or combinations of these two factors ... A regional study for the North-eastern and Eastern Wheatbelt of Western Australia was undertaken. The base data used to develop water supply areas included soil type, landscape units, geology, hydrogeology, native vegetation and existing far water resource infrastructure.

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Biogeochemical Processes And Seasonal Effects In Flow-Through Mesocosm Reactors Simulating Constructed Wetlands, Sarah J. Tritschler Jan 2007

Biogeochemical Processes And Seasonal Effects In Flow-Through Mesocosm Reactors Simulating Constructed Wetlands, Sarah J. Tritschler

Browse all Theses and Dissertations

Due to their distinctive environments, constructed wetlands are utilized to remediate groundwater that has been contaminated with chlorinated ethenes (i.e. perchloroethene) and other such contaminants. This research focuses on vertical flow mesocosm reactors housed in a greenhouse at Wright State University, which simulate a constructed wetland on Wright-Patterson Air Force Base. These reactors were studied to investigate the effects of vegetation and seasonal changes on the redox parameters present. Water samples were collected from six different reactors from late September/early October 2006 until August 2007. The reactors were sampled three days in a row and this sampling was done once …

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Annual Pasture Legume Options For Key Soil Types, Department Of Agriculture, Western Australia, Grains Research & Development Corporation Jan 2007

Annual Pasture Legume Options For Key Soil Types, Department Of Agriculture, Western Australia, Grains Research & Development Corporation

All other publications

No abstract provided.

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Evidence Of A Pre-Mount Simon, Half-Graben In Greene County, Ohio By Reprocessing A Wright State University Seismic Line, John Sink Jan 2007

Evidence Of A Pre-Mount Simon, Half-Graben In Greene County, Ohio By Reprocessing A Wright State University Seismic Line, John Sink

Browse all Theses and Dissertations

The reprocessing of the WSU2002 seismic line indicates the presence of a Precambrian half-graben. Also observed through this reprocessing is the possible presence of Paleozoic structures. Although Paleozoic features have been interpreted, variations in glacial drift thickness evidenced by glacial drift maps also may have contributed to a lower quality of stacked section in comparison to other seismic lines. WSU2002 was originally processed by Lauren Geophysical. The Lauren processing resulted in an image that was of much lower quality than corresponding seismic lines. The Lauren Geophysical processed section revealed many horizontal Paleozoic reflections, with no prominent reflectors beneath the Paleozoic. …

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Geophysical Reconnaissance Of Karst Features Associated With Sinkholes On The Antioch University Campus In Yellow Springs, Ohio: Western Area, Brent Matthew Zerkel Jan 2007

Geophysical Reconnaissance Of Karst Features Associated With Sinkholes On The Antioch University Campus In Yellow Springs, Ohio: Western Area, Brent Matthew Zerkel

Browse all Theses and Dissertations

Antioch University is located in Yellow Springs, OH. This study was conducted on the Antioch University Campus in the commons area and is concentrated on the area west of the easternmost sinkhole. The primary purpose of this study is to locate and identify buried anomalous karst features, such as joints and collapses that may be hazardous to nearby buildings on the Antioch University Campus. The secondary purposes of this study are to identify remaining features in the geophysical data that may be related to manmade structures, and to identify areas for future studies. It is known that an 8-inch steel …

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Seasonal Variation In The Redox Zones And Biogeochemical Processes Within The Constructed Wetland, Yussuf Mohamud Jan 2007

Seasonal Variation In The Redox Zones And Biogeochemical Processes Within The Constructed Wetland, Yussuf Mohamud

Browse all Theses and Dissertations

This research investigation focuses on the vertical distribution of dissolved inorganic species in the pore-water affected by redox processes and seasonal changes within a small constructed wetland located at the Wright-Patterson Air Force Base. This is a follow up study to an earlier investigation (Lach, 2004) at this site in 2003. Water samples were collected from influent, effluent and three layers of the constructed wetland through a network of nested piezometers in the vertical flow wetland from June 2005 to June 2006. Onsite analysis of temperature, pH and conductivity were carried out onsite. Major anions and cations were measured by …

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Impact Of Land Use On Water Quality In The Indian Lake Watershed: An Integrated Geographic Information Systems Approach, Michael Belke Jan 2007

Impact Of Land Use On Water Quality In The Indian Lake Watershed: An Integrated Geographic Information Systems Approach, Michael Belke

Browse all Theses and Dissertations

Geology and land use and land cover are the most important factors that influence water quality. The purpose of this study is to investigate how these factors operate in a rural watershed. Specifically, this thesis tests the feasibility of a proposed formula to relate how land use affects surface water quality and to infer hydrogeochemical reactions that control water chemistry through hydrogeochemical speciation and mineral stability relationships. Samples were collected from Indian Lake and its watershed in West-Central Ohio. BASINS, produced by the USEPA, was then used to delineate sub-watersheds and find the land use areas of these watersheds. The …

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Modeling Annual Extreme Precipitation In China Using The Generalized Extreme Value Distribution, Song Feng, Saralees Nadarajah, Qi Hu Jan 2007

Modeling Annual Extreme Precipitation In China Using The Generalized Extreme Value Distribution, Song Feng, Saralees Nadarajah, Qi Hu

Department of Earth and Atmospheric Sciences: Faculty Publications

Extreme precipitation events are the major causes of severe floods in China. In this study, four time series of daily, 2-day, 5-day, and 10-day annual maximum precipitation from 1951 to 2000 at 651 weather stations in China were analyzed. The generalized extreme value (GEV) distribution was used, to model the annual extreme precipitation events at each station. The GEV distribution was also modified to explore the linear temporal trends in the extreme events. The results showed that more than 12% of the stations have significant (p-value < 0.10) linear trends. Decreasing trends are mainly observed in northern China, and increasing trends are observed in the Yangtze River basin and northwestern China. The return periods of extreme participation have changed stations with significant temporal trends. The 50-year event observed in parts of the Yangtze River basin, and northwestern China during the 1951-60, has become a more frequent 25-year event in the 1990s. The spatial distribution of the return levels of the 651 stations are closely related to the climatic mean precipitation, and are influenced by the East Asian summer monsoon system (return levels are measures of extremity – for example, a 10 year return level is the value that can be expected to be exceeded on average once in every 10 years). The return period of extreme precipitation, that caused the 1998 severe floods in the Yangtze River basin, was also evaluated from a probabilistic perspective.

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