Temitope Ojo

Multi-parameter Instrument Array and Control System (MPIACS): a software interface implementation of real-time data acquisition and visualization for environmental monitoring

Recent developments in sensor technology over the past decade have shifted the paradigm in environmental as well as oceanographic sampling and monitoring. The environmental and oceanographic scientific communities continue to deploy more and more in situ sensors either as single-unit deployments for generation of time-series and vertical profiles or as a towed-array for mapping environmental variables in surface waters in multidimensional space. Emergency response activities are also enhanced by way of real-time geo-referenced data acquisition using mobile in situ sensor arrays. Against this backdrop, we developed a software interface for real-time acquisition, analysis and visualization from a towed-array of sensors. This is the Multi-parameter Instrument Array and Control System (MPIACS) described in this paper and was used in the fall of 2002 during a mock oil-spill exercise in Corpus Christi Bay, Texas under he auspices of the Texas General Land Office (TGLO). The interface is designed for correlative visualization along the transect between as many as six state variables or environmental indicators allowing the implementation of adaptive sampling schemes. The software can also be used for scheduled sampling of water quality parameters in surface waters.

A mobile monitoring system to understand the processes controlling episodic events in Corpus Christi Bay

Corpus Christi Bay (TX, USA) is a shallow wind-driven bay and thereby, can be characterized as a highly pulsed system. It cycles through various episodic events such as hypoxia, water column stratification, sediment resuspension, flooding, etc. Understanding of the processes that control these events requires an efficient observation system that can measure various hydrodynamic and water quality parameters at the multitude of spatial and temporal scales of interest. As part of our effort to implement an efficient observation system for Corpus Christi Bay, a mobile monitoring system was developed that can acquire and visualize data measured by various submersible sensors on an undulating tow-body deployed behind a research vessel. Along with this system, we have installed a downward-looking Acoustic Doppler Current Profiler to measure the vertical profile of water currents. Real-time display of each measured parameter intensity (measured value relative to a pre-set peak value) guides in selecting the transect route to capture the event of interest. In addition, large synchronized datasets measured by this system provide an opportunity to understand the processes that control various episodic events in the bay. To illustrate the capability of this system, datasets from two research cruises are presented in this paper that help to clarify processes inducing an inverse estuary condition at the mouth of the ship channel and hypoxia at the bottom of the bay. These measured datasets can also be used to drive numerical models to understand various environmental phenomena that control the water quality of the bay.

A mechanistic dissolved oxygen model of Corpus Christi Bay to understand critical processes causing hypoxia

Corpus Christi Bay (TX, USA) is a shallow wind-driven bay which experiences hypoxia (dissolved oxygen<2 mg/L) during the summer months in the southeast region of the bay. We have developed and installed real-time monitoring systems in the bay to measure various water quality, meteorological and hydrodynamic parameters. These systems can aid in determining the extent and frequency of hypoxic events in this energetic bay. A three-dimensional mechanistic dissolved oxygen model has been developed in this study to investigate the key processes that induce hypoxia in Corpus Christi (CC) Bay. This model includes variable advection and dispersion coefficients so that it can be driven by real-time monitoring hydrodynamic data. The results from model simulations indicate that hypoxia may occur at the lower depths of the bay when both stratification and higher biological activity conditions exist. The water column in the south-east part of the bay becomes stratified during calm wind conditions when there is inflow of hyper-saline water from the neighboring Laguna Madre waterbody. This condition, when combined with higher biological activity during the summer months, induces hypoxia at the lower depths of the bay. The simulation results also point out that physical transport processes have more pronounced effect on the DO distribution within the water column than the effects of biological activity. Therefore, it is necessary to develop suitable sampling strategies that will measure hydrodynamic data at greater spatial and temporal resolution. The integration of this data with our developed model will provide a useful tool to the stakeholders to assess the water quality of the bay in real time.

PORT FREEPORT'S "FLOWINFO": AN EXAMPLE OF AN INTEGRATED PORT NAVIGATION AND ENVIRONMENTAL DATA SYSTEM (IPNEDS)

Texas ports are rapidly expanding their operations because of increased tonnage and security requirements. As a result, they are also expanding their real-time data acquisition and display capabilities for navigational operations and homeland security. Ports such as Port Freeport are collaborating with Texas A&M UniversityCorpus Christi to develop, install and operate real-time data systems to deliver needed information to the Pilots and operations personnel. The ports need to significantly expand the scale of real-time programs, in terms of both types of observations (i.e., to include chemical and biological sensors in support of environmental and homeland security requirements) and area covered (i.e., both inshore and offshore). They also need, through cyber-infrastructure, to deliver a visualization of the converged data product to its Pilots and other stakeholders, all in a cost effective program. In collaboration with Port Freeport, we are developing the technology required for such an Integrated Port Navigation and Environmental Data System (IPNEDS). It will deliver not only a greatly expanded suite of physical parameters but also new state-ofthe-art capabilities to measure precisely, in situ and in real-time, standard environmental, chemical and biological parameters. Single-point measurements of currents will be augmented by HF-Radar-measured large spatial grids of coastal surface currents and ADCP-measured, vertical profiles of horizontal current velocity and directional wave parameters (height, period, direction).

Sensing the coastal environment

Abstract The spatial and temporal dynamics of near-shore ecosystems are being studied by the Conrad Blucher Institute for Surveying and Science at Texas A&M University-Corpus Christi with special consideration of episodic events associated with anthropogenic activity. Our growing array of estuarine and coastal monitoring stations in the Corpus Christi region supplies real-time, continuous input from a broad array of sensors (physical, chemical and biological) to feed comprehensive converged data sets that in turn foster, in a new context, the interpretation and evaluation of environmental perturba- tions (episodic events) and their ecological effects.

Estimating Colloidal Concentration Using Acoustic Backscatter

Interest has grown for using acoustic Doppler current profilers (ADCPs) to measure suspended solids concentrations (SSC) in aqueous environments because of the ability to make simultaneous unobtrusive long-term multipoint measurements with high spatial and temporal resolutions. The acoustic backscatter intensity (ABS) measured by ADCPs is a function of the particle size distribution, concentration, and incident acoustic signal strength and thus provides the theoretical basis for measuring SSC. The applicability of using ABS from a 2400-kHz ADCP to estimate SSC in units of volume concentration over variable particle size distributions is evaluated in a controlled laboratory study. Results from this research show a log-linear relationship between ABS and volume concentrations over variable size distributions. Volume concentrations predicted from the sonar equation using measured ABS and empirically derived response coefficients compare well with the measured concentrations over the full range of concentrations and particle size distributions tested. The ABS response is shown to be linear with the theoretical Rayleigh scattering target strength, calculated from the empirical particle size distribution, and thus explains the observed linearity over a variable particle size distribution. These results indicate that ABS can be used to provide meaningful volume concentration estimates for characteristically variable colloidal suspensions.

REALTIME GEO-REFERENCED DETECTION OF DISPERSED OIL PLUMES

The current SMART protocol used by the U.S. Coast Guard relies on traditional ex-situ fluorometers that require physical transport of the sample from the water column to the instruments. While samp...

Understanding particle-mediated contaminant transport through real-time monitoring

Aquatic particles represent a significant sink for hydrophobic contaminants including Poly-Chlorinated Biphenyls (PCB). The riverbed of the Hudson River near Ft. Edward, New York is contaminated with PCBs due to the discharge of these chemicals from two General Electric Company (GE) capacitor manufacturing plants into the river from approximately 1947 to 1977. The contaminated sediments continue to be an active PCB source to the water column and biota. GE initiated remedial dredging operations in 2009 to remove the contaminated sediments and subsequently reduce PCB concentrations in fish, river water and sediment, and to minimize downstream transport. To meet these objectives, Environmental Protection Agency (EPA) required GE to follow three engineering performance standards (production, re-suspension and residual) during the dredging operation. Data collected from the River and Estuary Observation Network (REON) are presented in this paper to provide evidence of the capability of the observation network in characterizing particle dynamics which can guide in adaptive dredging operation to meet the objectives, and to track the improvements of water quality due to this remediation action. In this study, the particle dynamics at the Thompson Island Pool (TIP), where high PCB concentrations are found in the sediment and biota, were characterized with respect to stream velocity profiles, suspended sediment concentration and particle size distribution during a flood event. This characterization presented sediment resuspension and advection as potential mechanisms for sediment and sediment bound PCBs transport during a flood event. Moreover, integration of the monitoring datasets with the PCB fate and transport model can serve as a valuable diagnostic tool for investigating the impacts of PCB on the ecosystem of the Hudson River.

Estimating sub-surface dispersed oil concentration using acoustic backscatter response

The recent Deepwater Horizon disaster resulted in a dispersed oil plume at an approximate depth of 1000 m. Several methods were used to characterize this plume with respect to concentration and spatial extent including surface supported sampling and autonomous underwater vehicles with in situ instrument payloads. Additionally, echo sounders were used to track the plume location, demonstrating the potential for remote detection using acoustic backscatter (ABS). This study evaluated use of an Acoustic Doppler Current Profiler (ADCP) to quantitatively detect oil-droplet suspensions from the ABS response in a controlled laboratory setting. Results from this study showed log-linear ABS responses to oil-droplet volume concentration. However, the inability to reproduce ABS response factors suggests the difficultly in developing meaningful calibration factors for quantitative field analysis. Evaluation of theoretical ABS intensity derived from the particle size distribution provided insight regarding method sensitivity in the presence of interfering ambient particles.

SENSE IT - student created water quality sensors

This paper describes the structure and impact of an NSF-funded ITEST project designed to enrich science, technology, engineering, and mathematics (STEM) education using educational modules that teach students to construct, program, and test a series of sensors used to monitor water quality. During the three years of the SENSE IT project, over 60 teachers across New York, New Jersey and Washington were provided with equipment and professional development, and then implemented the modules in their classrooms with over 2,000 middle and high school students. Project evaluation results indicate that the curriculum was well received by teachers and students, could be integrated into several different subject areas and types of courses, and was effective for a wide range of students.