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Articles 241 - 270 of 387

Full-Text Articles in Marine Biology

Reconstructing Twentieth-Century Sea Surface Temperature Variability In The Southwest Pacific: A Replication Study Using Multiple Coral Sr/Ca Records From New Caledonia, Kristine L. Delong, Terrence M. Quinn, Frederick W. Taylor Dec 2007

Reconstructing Twentieth-Century Sea Surface Temperature Variability In The Southwest Pacific: A Replication Study Using Multiple Coral Sr/Ca Records From New Caledonia, Kristine L. Delong, Terrence M. Quinn, Frederick W. Taylor

Marine Science Faculty Publications

Coral‐based climate reconstructions typically have not used multiple cores from a region to capture and replicate a climate signal largely because of concerns of coral conservation, analytical expense, and time constraints. Coral Sr/Ca reproducibility through the twentieth century was investigated using three intracolony and three intercolony coral records from the reefs offshore of Amédée Island, New Caledonia. Different sampling resolutions were examined in coral Sr/Ca (fortnightly and monthly) and δ18O (fortnightly, monthly, and seasonally) as well as similar scale subsampling of the daily in situ sea surface temperature (SST) record. The mean coral Sr/Ca, δ18O, and …

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Upper Ocean Response Of The Mesoamerican Barrier Reef System To Hurricane Mitch And Coastal Freshwater Inputs: A Study Using Sea-Viewing Wide Field-Of-View Sensor (Seawifs) Ocean Color Data And A Nested-Grid Ocean Circulation Model, Jinyu Sheng, Liang Wang, Serge Andrefouet, Chuanmin Hu, Bruce G. Hatcher, Frank E. Muller-Karger, Bjoern Kjerfve, William D. Heyman, Bo Yang Jul 2007

Upper Ocean Response Of The Mesoamerican Barrier Reef System To Hurricane Mitch And Coastal Freshwater Inputs: A Study Using Sea-Viewing Wide Field-Of-View Sensor (Seawifs) Ocean Color Data And A Nested-Grid Ocean Circulation Model, Jinyu Sheng, Liang Wang, Serge Andrefouet, Chuanmin Hu, Bruce G. Hatcher, Frank E. Muller-Karger, Bjoern Kjerfve, William D. Heyman, Bo Yang

Marine Science Faculty Publications

The passage of category‐5 Hurricane Mitch through the Mesoamerican Barrier Reef System (MBRS) in October 1998 was an extreme event with the potential to create unusual patterns of reef connectivity. The impact of this hurricane on the upper ocean of the MBRS is investigated using a triply nested grid ocean circulation modeling system. The model results are validated with contemporaneous ocean color data from the Sea‐viewing Wide Field‐of‐view Sensor (SeaWiFS) satellite and oceanographic measurements in the MBRS. The nested grid system is forced by 6‐hourly National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) winds for the first 294 …

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Ocean Currents And Sea Surface Heights Estimated Across The West Florida Shelf, Yonggang Liu, Robert H. Weisberg Jun 2007

Ocean Currents And Sea Surface Heights Estimated Across The West Florida Shelf, Yonggang Liu, Robert H. Weisberg

Marine Science Faculty Publications

The across-shelf structures of the ocean circulation and the associated sea surface height (SSH) variability are examined on the west Florida shelf (WFS) for the 3-yr interval from September 1998 to December 2001. Five sets of characteristic circulation patterns are extracted from 2-day, low-pass-filtered data using the self-organizing map: extreme upwelling and downwelling structures with strong currents, asymmetric upwelling and downwelling structures with moderate currents, and a set of transitional structures with weak currents. The temporal variations of these structures are coherent with the local winds on synoptic weather time scales. On seasonal time scales they are related to both …

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Bathymetric Alterations Due To Urbanization And Their Effects On Residual Salinity, Flow Field And Transport Time For Tampa Bay, Florida, Amanda J. Linville May 2007

Bathymetric Alterations Due To Urbanization And Their Effects On Residual Salinity, Flow Field And Transport Time For Tampa Bay, Florida, Amanda J. Linville

USF Tampa Graduate Theses and Dissertations

Growth and development over the past one hundred years has resulted in the construction of causeways and navigational channels in Tampa Bay. Urbanization has lead to bathymetric alterations of the bay, and thus has effectively changed the residual salinity, flow fields, and transport time in Tampa Bay. In this study a numerical ocean model of Tampa Bay was first used to simulate the circulation for 2001-2003 using present day bathymetry. Then, an identical simulation was performed using the bathymetry generated from 1879 depth soundings. The residual (30-day time average) circulation fields and salinity, along with transport times was intercompared for …

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Particulate Organic Carbon Fluxes Along Upwelling-Dominated Continental Margins: Rates And Mechanisms, Robert C. Thunell, Claudia Benitez-Nelson, Ramon Varela, Yrene Astor, Frank E. Muller-Karger Mar 2007

Particulate Organic Carbon Fluxes Along Upwelling-Dominated Continental Margins: Rates And Mechanisms, Robert C. Thunell, Claudia Benitez-Nelson, Ramon Varela, Yrene Astor, Frank E. Muller-Karger

Marine Science Faculty Publications

Time series sediment trap samples were used to examine the rates and mechanisms of particulate organic carbon (POC) flux at three continental margin locations, Santa Barbara Basin, Cariaco Basin, and Guaymas Basin, marked by seasonal upwelling and high primary production. The mean POC flux in Santa Barbara Basin (0.096 g m−2 d−1) is nearly twice that of Cariaco Basin and 4 times higher than that in Guaymas Basin, with all three sites having POC fluxes significantly higher than the open ocean average (0.007 g m−2 d−1). In Cariaco Basin, the only site with available …

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Euphotic Zone Depth: Its Derivation And Implication To Ocean-Color Remote Sensing, Zhongping Lee, Alan Weidemann, John Kindle, Robert Arnone, Kendall L. Carder, Curtiss Davis Mar 2007

Euphotic Zone Depth: Its Derivation And Implication To Ocean-Color Remote Sensing, Zhongping Lee, Alan Weidemann, John Kindle, Robert Arnone, Kendall L. Carder, Curtiss Davis

Marine Science Faculty Publications

Euphotic zone depth, z1%, reflects the depth where photosynthetic available radiation (PAR) is 1% of its surface value. The value of z1% is a measure of water clarity, which is an important parameter regarding ecosystems. Based on the Case‐1 water assumption, z1% can be estimated empirically from the remotely derived concentration of chlorophyll‐a ([Chl]), commonly retrieved by employing band ratios of remote sensing reflectance (Rrs). Recently, a model based on water's inherent optical properties (IOPs) has been developed to describe the vertical attenuation of visible solar radiation. Since IOPs can be near‐analytically calculated …

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Multivariate Reconstruction Of Missing Data In Sea Surface Temperature, Chlorophyll, And Wind Satellite Fields, Aida Alvera-Azcarate, Alexander Barth, J. M. Beckers, Robert H. Weisberg Mar 2007

Multivariate Reconstruction Of Missing Data In Sea Surface Temperature, Chlorophyll, And Wind Satellite Fields, Aida Alvera-Azcarate, Alexander Barth, J. M. Beckers, Robert H. Weisberg

Marine Science Faculty Publications

An empirical orthogonal function–based technique called Data Interpolating Empirical Orthogonal Functions (DINEOF) is used in a multivariate approach to reconstruct missing data. Sea surface temperature (SST), chlorophyll a concentration, and QuikSCAT winds are used to assess the benefit of a multivariate reconstruction. In particular, the combination of SST plus chlorophyll, SST plus lagged SST plus chlorophyll, and SST plus lagged winds have been studied. To assess the quality of the reconstructions, the reconstructed SST and winds have been compared to in situ data. The combination of SST plus chlorophyll, as well as SST plus lagged SST plus chlorophyll, significantly improves …

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Satellite-Derived Surface Current Divergence In Relation To Tropical Atlantic Sst And Wind, Robert W. Helber, Robert H. Weisberg, Fabrice Bonjean, Eric S. Johnson, Gary S. Lagerloef Mar 2007

Satellite-Derived Surface Current Divergence In Relation To Tropical Atlantic Sst And Wind, Robert W. Helber, Robert H. Weisberg, Fabrice Bonjean, Eric S. Johnson, Gary S. Lagerloef

Marine Science Faculty Publications

The relationships between tropical Atlantic Ocean surface currents and horizontal (mass) divergence, sea surface temperature (SST), and winds on monthly-to-annual time scales are described for the time period from 1993 through 2003. Surface horizontal mass divergence (upwelling) is calculated using surface currents estimated from satellite sea surface height, surface vector wind, and SST data with a quasi-linear, steady-state model. Geostrophic and Ekman dynamical contributions are considered. The satellite-derived surface currents match climatological drifter and ship-drift currents well, and divergence patterns are consistent with the annual north–south movement of the intertropical convergence zone (ITCZ) and equatorial cold tongue evolution. While the …

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Effects Of Ice Melting On Grace Observations Of Ocean Mass Trends, Don P. Chambers, Mark E. Tamisiea, R Steven Nerem, John C. Ries Mar 2007

Effects Of Ice Melting On Grace Observations Of Ocean Mass Trends, Don P. Chambers, Mark E. Tamisiea, R Steven Nerem, John C. Ries

Marine Science Faculty Publications

The Gravity Recovery and Climate Experiment (GRACE) was designed to measure variations in the Earth's gravity field from space at monthly intervals. Researchers have used these data to measure changes in water mass over various regions, including the global oceans and continental ice sheets covering Greenland and Antarctica. However, GRACE data must be smoothed in these analyses and the effects of geocenter motions are not included. In this study, we examine what effect each of these has in the computation of ocean mass trends using a simulation of ice melting on Greenland, Antarctica, and mountain glaciers. We find that the …

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Progressive Dolomitization Of Florida Limestone Recorded By Alkaline Earth Element Concentrations In Saline, Geothermal, Submarine Springs, Johan Schijf, Robert H. Byrne Jan 2007

Progressive Dolomitization Of Florida Limestone Recorded By Alkaline Earth Element Concentrations In Saline, Geothermal, Submarine Springs, Johan Schijf, Robert H. Byrne

Marine Science Faculty Publications

Studies in the late 1970s revealed that the effluents of saline, geothermal, submarine springs on the West Florida Shelf have compositions nearly identical to seawater, except for distinct Ca enrichments and Mg depletions, probably resulting from dolomitization. During annual visits between 1996 and 2003 we collected high‐purity effluents from four submarine springs and from Warm Mineral Springs (WMS), which is located on land. Filtered effluents were analyzed for major ions and for Sr and Ba. These analyses confirm the seawater‐like composition of the effluents as well as the Ca enrichment and Mg depletion. The alkaline earth elements Sr and Ba, …

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Coral-Based Climate Variability In The Western Pacific Warm Pool Since 1867, Terrence M. Quinn, Frederick W. Taylor, Thomas J. Crowley Nov 2006

Coral-Based Climate Variability In The Western Pacific Warm Pool Since 1867, Terrence M. Quinn, Frederick W. Taylor, Thomas J. Crowley

Marine Science Faculty Publications

We have generated monthly resolved, stable isotope (δ18O and δ13C) and Sr/Ca time series from a massive Porites coral from Rabaul (4°S, 152°E): a site located in the warmest sector of the Western Pacific Warm Pool (WPWP). The coral δ18O and Sr/Ca time series are well correlated to each other and positive excursions in both records coincide with times of ENSO warm phase events. These time series contain abundant interannual variability that exhibits the well‐recognized pattern of low amplitude ENSO variation between ∼1920–1960 and high amplitude ENSO variation between 1880–1920 and 1960–1997. The …

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Red Tides In The Gulf Of Mexico: Where, When, And Why?, John J. Walsh, J. K. Jolliff, B. P. Darrow, J. M. Lenes, S. P. Milroy, A. Remsen, D. A. Dieterle, Kendall L. Carder, F. R. Chen, Gabriel A. Vargo, Robert H. Weisberg, Kent A. Fanning, Eugene Shinn, K. A. Steidinger, Cynthia A. Heil, C. R. Tomas, J. S. Prospero, T. N. Lee, G. J. Kirkpatrick, T. E. Whitledge, D. A. Stockwell, T. A. Villareal, A. E. Jochens, P. S. Bontempi, Frank E. Muller-Karger Nov 2006

Red Tides In The Gulf Of Mexico: Where, When, And Why?, John J. Walsh, J. K. Jolliff, B. P. Darrow, J. M. Lenes, S. P. Milroy, A. Remsen, D. A. Dieterle, Kendall L. Carder, F. R. Chen, Gabriel A. Vargo, Robert H. Weisberg, Kent A. Fanning, Eugene Shinn, K. A. Steidinger, Cynthia A. Heil, C. R. Tomas, J. S. Prospero, T. N. Lee, G. J. Kirkpatrick, T. E. Whitledge, D. A. Stockwell, T. A. Villareal, A. E. Jochens, P. S. Bontempi, Frank E. Muller-Karger

Marine Science Faculty Publications

Independent data from the Gulf of Mexico are used to develop and test the hypothesis that the same sequence of physical and ecological events each year allows the toxic dinoflagellate Karenia brevis to become dominant. A phosphorus‐rich nutrient supply initiates phytoplankton succession, once deposition events of Saharan iron‐rich dust allow Trichodesmium blooms to utilize ubiquitous dissolved nitrogen gas within otherwise nitrogen‐poor sea water. They and the co‐occurring K. brevis are positioned within the bottom Ekman layers, as a consequence of their similar diel vertical migration patterns on the middle shelf. Upon onshore upwelling of these near‐bottom seed populations to CDOM‐rich …

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Subcentennial-Scale Climatic And Hydrologic Variability In The Gulf Of Mexico During The Early Holocene, Jenna M. Lodico, Benjamin P. Flower, Terrence M. Quinn Sep 2006

Subcentennial-Scale Climatic And Hydrologic Variability In The Gulf Of Mexico During The Early Holocene, Jenna M. Lodico, Benjamin P. Flower, Terrence M. Quinn

Marine Science Faculty Publications

An early Holocene record from the Gulf of Mexico (GOM) reveals climatic and hydrologic changes during the interval from 10.5 to 7 thousand calendar years before present from paired analyses of Mg/Ca and δ18O on foraminiferal calcite. The sea surface temperature record based on foraminiferal Mg/Ca contains six oscillations and an overall ∼1.5°C warming that appears to be similar to the September–March insolation difference. The δ18O of seawater in the GOM (δ18OGOM) record contains six oscillations, including a −0.8‰ excursion that may be associated with the “8.2 ka climate event” or a …

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Evaluation Of New Grace Time-Variable Gravity Data Over The Ocean, Don P. Chambers Sep 2006

Evaluation Of New Grace Time-Variable Gravity Data Over The Ocean, Don P. Chambers

Marine Science Faculty Publications

Monthly GRACE gravity field models from the three science processing centers (CSR, GFZ, and JPL) are analyzed for the period from February 2003 to April 2005 over the ocean. The data are used to estimate maps of the mass component of sea level at smoothing radii of 500 km and 750 km. In addition to using new gravity field models, a filter has been applied to estimate and remove systematic errors in the coefficients that cause erroneous patterns in the maps of equivalent water level. The filter is described and its effects are discussed. The GRACE maps have been evaluated …

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Cold Event In The South Atlantic Bight During Summer Of 2003: Anomalous Hydrographic And Atmospheric Conditions, Alfredo Aretxabaleta, James R. Nelson, Jack O. Blanton, Harvey E. Seim, Francisco E. Werner, John M. Bane, Robert H. Weisberg Jun 2006

Cold Event In The South Atlantic Bight During Summer Of 2003: Anomalous Hydrographic And Atmospheric Conditions, Alfredo Aretxabaleta, James R. Nelson, Jack O. Blanton, Harvey E. Seim, Francisco E. Werner, John M. Bane, Robert H. Weisberg

Marine Science Faculty Publications

Unusually cold seawater temperatures were observed along much of the U.S. eastern seaboard during the summer of 2003. In this study, hydrographic and atmospheric observations from spring through summer were analyzed to track the evolution of the cold water event in the South Atlantic Bight (SAB) and investigate links to various forcing mechanisms. The hydrographic observations included 13 cross‐shelf transects over the central region of the SAB, surface temperature time series from several NDBC stations, and bottom temperatures from a mid shelf mooring. Atmospheric data were obtained from NDBC stations. Additional data included water level from NOS stations and river …

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Performance Evaluation Of The Self-Organizing Map For Feature Extraction, Yonggang Liu, Robert H. Weisberg, Christopher N. K. Mooers May 2006

Performance Evaluation Of The Self-Organizing Map For Feature Extraction, Yonggang Liu, Robert H. Weisberg, Christopher N. K. Mooers

Marine Science Faculty Publications

Despite its wide applications as a tool for feature extraction, the Self‐Organizing Map (SOM) remains a black box to most meteorologists and oceanographers. This paper evaluates the feature extraction performance of the SOM by using artificial data representative of known patterns. The SOM is shown to extract the patterns of a linear progressive sine wave. Sensitivity studies are performed to ascertain the effects of the SOM tunable parameters. By adding random noise to the linear progressive wave data, it is demonstrated that the SOM extracts essential patterns from noisy data. Moreover, the SOM technique successfully chooses among multiple sets of …

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An Evaluation Of The Along Track Reef Imaging System (Atris) For Efficient Reef Monitoring And Rapid Groundtruthing Of Eaarl Lidar, Nicole O. Caesar Apr 2006

An Evaluation Of The Along Track Reef Imaging System (Atris) For Efficient Reef Monitoring And Rapid Groundtruthing Of Eaarl Lidar, Nicole O. Caesar

USF Tampa Graduate Theses and Dissertations

The Along-Track Reef-Imaging System (ATRIS) is a vessel-mounted, digital camera, depth sounder and Global Positioning System (GPS) package that facilitates the rapid capture of underwater images in shallow-water benthic environments. This technology has the potential to collect ecologically significant data, particularly in benthic habitats less than 10 m in depth, with better location referencing and in less time than is required for surveys carried out by Scuba divers. In October 2004, ATRIS was tested coincidently with SCUBA-assisted video along transects on five patch reefs in Biscayne National Park. Images from both data sets were subsampled, viewed, and benthic cover under …

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Assessment Of Image Analysis As A Measure Of Scleractinian Coral Growth, Steven K. Gustafson Mar 2006

Assessment Of Image Analysis As A Measure Of Scleractinian Coral Growth, Steven K. Gustafson

USF Tampa Graduate Theses and Dissertations

Image analysis was used to measure basal areas of selected colonies of Montastraea annularis and Porites astreoides, following the colonies over a three-year period from 2002 to 2004. Existing digital images of permanently-marked quadrats in the Caye Caulker Marine Reserve, Belize, were selected based on image quality and availability of images of selected quadrats for all three years. Annual growth rates were calculated from the basal-area measurements. Mean growth rates (radial skeletal extension) for M. annularis and P. astreoides were 0.02 cm yr-1 and -0.20 cm yr-1, respectively. Basal area measurements demonstrated a large degree of variability. Increases were approximately …

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Reproducibility Of Geochemical And Climatic Signals In The Atlantic Coral Montastraea Faveolata, Jennifer M. Smith, Terrence M. Quinn, Kevin P. Helmle, Robert B. Halley Mar 2006

Reproducibility Of Geochemical And Climatic Signals In The Atlantic Coral Montastraea Faveolata, Jennifer M. Smith, Terrence M. Quinn, Kevin P. Helmle, Robert B. Halley

Marine Science Faculty Publications

Monthly resolved, 41‐year‐long stable isotopic and elemental ratio time series were generated from two separate heads of Montastraea faveolata from Looe Key, Florida, to assess the fidelity of using geochemical variations in Montastraea, the dominant reef‐building coral of the Atlantic, to reconstruct sea surface environmental conditions at this site. The stable isotope time series of the two corals replicate well; mean values of δ18O and δ13C are indistinguishable between cores (compare 0.70‰ versus 0.68‰ for δ13C and −3.90‰ versus −3.94‰ for δ18O). Mean values from the Sr/Ca time series differ by …

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Observing Seasonal Steric Sea Level Variations With Grace And Satellite Altimetry, Don P. Chambers Mar 2006

Observing Seasonal Steric Sea Level Variations With Grace And Satellite Altimetry, Don P. Chambers

Marine Science Faculty Publications

Sea level rises and falls as the temperature and salinity of the water column varies, which is known as steric sea level. Sea level also changes as water mass is redistributed within the ocean or is added or removed. Satellite radar altimeters measure the combination of both effects, while the Gravity Recovery and Climate Experiment (GRACE) was designed to measure time variable gravity caused by movement of water mass. Theoretically, altimetry and GRACE data can be combined in order to compute the steric sea level variations. We test this by combining current GRACE and Jason 1 altimeter data and comparing …

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Circulation Of Tampa Bay Driven By Buoyancy, Tides, And Winds, As Simulated Using A Finite Volume Coastal Ocean Model, Robert H. Weisberg, Lianyuan Zheng Jan 2006

Circulation Of Tampa Bay Driven By Buoyancy, Tides, And Winds, As Simulated Using A Finite Volume Coastal Ocean Model, Robert H. Weisberg, Lianyuan Zheng

Marine Science Faculty Publications

The circulation of Tampa Bay is investigated using a high-resolution, three-dimensional, density-dependent, finite volume coastal ocean model (FVCOM) that includes Tampa Bay, the intracoastal waterway, and the inner portion of the west Florida continental shelf. Model performance over the three-month interval, September to November 2001, is assessed against available tide gauge and velocity profiler data before using the model to describe the circulation as driven by rivers, tides, and winds. Because of a mean wind velocity vector directed down the estuary axis, we ran a parallel model experiment without winds to distinguish the estuarine circulation by gravitational convection from the …

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Patterns Of Ocean Current Variability On The West Florida Shelf Using The Self-Organizing Map, Yonggang Liu, Robert H. Weisberg Jun 2005

Patterns Of Ocean Current Variability On The West Florida Shelf Using The Self-Organizing Map, Yonggang Liu, Robert H. Weisberg

Marine Science Faculty Publications

Patterns of ocean current variability are examined on the West Florida Shelf by a neural network analysis based on the self‐organizing map (SOM), using time series of moored velocity data that span the interval October 1998–September 2001. Three characteristic spatial patterns are extracted in a 3 × 4 SOM array: spatially coherent southeastward and northwestward flow patterns with strong currents and a transition pattern of weak currents. On the synoptic weather timescale the variations of these patterns are coherent with the local winds. On the seasonal timescale the variations of the patterns are coherent with both the local winds and …

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Interannual And Decadal Variability Of The Western Pacific Sea Surface Condition For The Years 1787-2000: Reconstruction Based On Stable Isotope Record From A Guam Coral, Ryuji Asami, Tsutomu Yamada, Yasufumi Iryu, Terrence M. Quinn, Christopher P. Meyer, Gustav Paulay May 2005

Interannual And Decadal Variability Of The Western Pacific Sea Surface Condition For The Years 1787-2000: Reconstruction Based On Stable Isotope Record From A Guam Coral, Ryuji Asami, Tsutomu Yamada, Yasufumi Iryu, Terrence M. Quinn, Christopher P. Meyer, Gustav Paulay

Marine Science Faculty Publications

We present a monthly resolved, 213‐year stable isotope time series from a coral from Guam (13°N, 145°E), which is located on the northern edge of the western Pacific warm pool. Oxygen isotopic composition of the coral skeleton (δ18Ocoral) shows seasonal, interannual, and decadal variability, which documents significant oceanographic changes related to thermal and hydrologic variations in this region. The δ18Ocoral anomaly reflects sea surface temperature (SST) anomaly and sea surface salinity (SSS) anomaly with significant r values of −0.69 and 0.49, respectively, which are strongly linked to oceanographic changes that occur during El …

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Interannual Temperature Variability In The Tropical Pacific And Lagrangian Heat Transport Pathways, C. L. Holland, Gary T. Mitchum Mar 2005

Interannual Temperature Variability In The Tropical Pacific And Lagrangian Heat Transport Pathways, C. L. Holland, Gary T. Mitchum

Marine Science Faculty Publications

In a previous study we found that volume variability during an El Ni (n) over tildeo-Southern Oscillation (ENSO) event is well described by variations in, and redistribution of, the heat content for any given region within the tropical Pacific. In this study we use numerical model temperature and velocity fields in a Lagrangian analysis of heat content variability. These three-dimensional fields are used to examine specific warm and cool anomaly regions by computing trajectories back through time to the origins of the anomalously warm or cool water. In particular, we find that three distinct pathways are important in creating and …

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Diffuse Attenuation Coefficient Of Downwelling Irradiance: An Evaluation Of Remote Sensing Methods, Zhongping Lee, Miroslaw Darecki, Kendall L. Carder, Curtiss O. Davis, Dariusz Stramski, W. Joseph Rhea Feb 2005

Diffuse Attenuation Coefficient Of Downwelling Irradiance: An Evaluation Of Remote Sensing Methods, Zhongping Lee, Miroslaw Darecki, Kendall L. Carder, Curtiss O. Davis, Dariusz Stramski, W. Joseph Rhea

Marine Science Faculty Publications

The propagation of downwelling irradiance at wavelength λ from surface to a depth (z) in the ocean is governed by the diffuse attenuation coefficient, (λ). There are two standard methods for the derivation of (λ) in remote sensing, which both are based on empirical relationships involving the blue‐to‐green ratio of ocean color. Recently, a semianalytical method to derive (λ) from reflectance has also been developed. In this study, using (490) and (443) as examples, we compare the (λ) values derived from the three methods using data collected in three different regions that cover oceanic and coastal waters, with …

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El Nino Southern Oscillation-Related Salinity Variations Recorded In The Skeletal Geochemistry Of A Porites Coral From Espiritu Santo, Vanuatu, K. H. Kilbourne, Terrence M. Quinn, Frederick W. Taylor, Thierry Delcroix, Yves Gouriou Oct 2004

El Nino Southern Oscillation-Related Salinity Variations Recorded In The Skeletal Geochemistry Of A Porites Coral From Espiritu Santo, Vanuatu, K. H. Kilbourne, Terrence M. Quinn, Frederick W. Taylor, Thierry Delcroix, Yves Gouriou

Marine Science Faculty Publications

Coral skeletal geochemistry offers the potential to reconstruct the sea surface salinity (SSS) history of the tropical oceans on seasonal to interannual and perhaps centennial timescales because of the strong link between variation in SSS and seawater δ18O in tropical regions. We explore this potential using a monthly resolved, 65‐year record of skeletal δ18O and Sr/Ca variations in a Porites coral from Espiritu Santo, Vanuatu. We demonstrate that El Niño–Southern Oscillation–related climate variability strongly influences coral δ18O at Santo through local salinity changes associated with the position of the South Pacific Convergence Zone and …

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Nitrogen Isotope Dynamics Of The Cariaco Basin, Venezuela, Robert C. Thunell, Daniel M. Sigman, Frank E. Muller-Karger, Yrene Astor, Ramon Varela Sep 2004

Nitrogen Isotope Dynamics Of The Cariaco Basin, Venezuela, Robert C. Thunell, Daniel M. Sigman, Frank E. Muller-Karger, Yrene Astor, Ramon Varela

Marine Science Faculty Publications

We report 15N/14N measurements of water column nitrate and ammonium, sinking particles, and sediments from the Cariaco Basin, an anoxic marine basin off the coast of Venezuela. Water column denitrification occurring in the basin has only a very small isotopic imprint on nitrate in the basin because nitrate consumption is nearly complete in the actively denitrifying water near the oxic/anoxic interface (∼275 m). Being free of a large denitrification signal, the δ15N of shallow thermocline nitrate is ∼3.5‰, significantly lower than the mean deep ocean nitrate δ15N of 5‰. This may be due …

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Preliminary Observations Of Global Ocean Mass Variations With Grace, D. Chambers, J. Wahr, R Steven Nerem Jul 2004

Preliminary Observations Of Global Ocean Mass Variations With Grace, D. Chambers, J. Wahr, R Steven Nerem

Marine Science Faculty Publications

Monthly estimates of the Earth's gravitational field from the GRACE mission are used to construct a time‐series of global mean ocean mass variations between August 2002 and December 2003. This time‐series is compared to a mean climatology determined from satellite altimeter measurements of global mean sea level corrected for the steric variation. The GRACE observations show a seasonal exchange of water mass with the continents of the same magnitude (∼8.5 mm) and phase (maximum in early‐ to mid‐October) as the steric‐corrected altimetry. This is one of the first direct validations over the ocean of the primary GRACE science mission to …

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Tide, Buoyancy, And Wind-Driven Circulation Of The Charlotte Harbor Estuary: A Model Study, Lianyuan Zheng, Robert H. Weisberg Jun 2004

Tide, Buoyancy, And Wind-Driven Circulation Of The Charlotte Harbor Estuary: A Model Study, Lianyuan Zheng, Robert H. Weisberg

Marine Science Faculty Publications

The circulation of the Charlotte Harbor (CH) estuary is explored with a primitive equation model that encompasses the estuary and the adjacent West Florida Shelf. Tidal forcing is from the shelf through the inlets. We use the M2, S2, K1, and O1 constituents that account for 95% of the shelf tidal variance. River inflows are by the Peace, Myakka, and Caloosahatchee Rivers at their spring 1998 mean values. Wind effects are considered for upwelling or downwelling favorable winds that are either held constant or allowed to oscillate with varying periodicities. These factors are …

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Generation, Transport, And Preservation Of The Alkenone-Based U37K' Sea Surface Temperature Index In The Water Column And Sediments Of The Cariaco Basin (Venezuela), Miguel A. Goni, Mark P. Woodworth, Heather L. Aceves, Robert C. Thunell, Eric Tappa, David Black, Frank E. Muller-Karger, Yrene Astor, Ramon Varela Jun 2004

Generation, Transport, And Preservation Of The Alkenone-Based U37K' Sea Surface Temperature Index In The Water Column And Sediments Of The Cariaco Basin (Venezuela), Miguel A. Goni, Mark P. Woodworth, Heather L. Aceves, Robert C. Thunell, Eric Tappa, David Black, Frank E. Muller-Karger, Yrene Astor, Ramon Varela

Marine Science Faculty Publications

Alkenone fluxes in the water column of the Cariaco Basin ranged from 12 to 20 μg m−2 d−1 and were inversely related to upwelling strength. The U37K′ ratios of sinking particles varied from 0.78 to 0.96 and exhibited seasonal changes that were coherent with a 7°C variation in sea surface temperature (SST). The correlation between SST and U37K′ ratios closely overlapped with the calibration of Prahl et al. [1988]. Alkenone burial fluxes in Cariaco Basin sediments varied markedly over the past ∼6000 years, ranging from 0.2 to 5 μg m−2 d−1 …

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