Numerical modeling of thermal bar and stratification pattern in Lake Ontario using the EFDC model

Thermal bar is an important phenomenon in large, temperate lakes like Lake Ontario. Spring thermal bar formation reduces horizontal mixing, which in turn, inhibits the exchange of nutrients. Evolution of the spring thermal bar through Lake Ontario is simulated using the 3D hydrodynamic model Environmental Fluid Dynamics Code (EFDC). The model is forced with the hourly meteorological data from weather stations around the lake, flow data for Niagara and St. Lawrence rivers, and lake bathymetry. The simulation is performed from April to July, 2011; on a 2-km grid. The numerical model has been calibrated by specifying: appropriate initial temperature and solar radiation attenuation coefficients. The existing evaporation algorithm in EFDC is updated to modified mass transfer approach to ensure correct simulation of evaporation rate and latent heatflux. Reasonable values for mixing coefficients are specified based on sensitivity analyses. The model simulates overall surface temperature profiles well (RMSEs between 1-2°C). The vertical temperature profiles during the lake mixed phase are captured well (RMSEs < 0.5°C), indicating that the model sufficiently replicates the thermal bar evolution process. An update of vertical mixing coefficients is under investigation to improve the summer thermal stratification pattern. Keywords: Hydrodynamics, Thermal BAR, Lake Ontario, GIS

ALOS-2/PALSAR-2 Calibration, Validation, Science and Applications

Twelve edited original papers on the latest and state-of-art results of topics ranging from calibration, validation, and science to a wide range of applications using ALOS-2/PALSAR-2. We hope you will find them useful for your future research

A framework for mapping cumulative threats and its application to Canada

Methods for cumulative threat mapping, such as the human footprint, have been rapidly developing to inform the management of biodiversity and ecosystem services. Here, I perform the first comprehensive literature review establishing what methods are used, what threats are mapped and where, and if threats or impacts are mapped statically or dynamically in time. From knowledge gained in the review, I compiled geospatial datasets in a geographic information system to map the first Canadian human footprint. Subsequently, I answer where the most intact and heavily threatened areas are, what the most prevalent threats in Canada are and assess the accuracy of the data through a technical validation. This thesis contributes to conservation science by highlighting where regional studies are lacking, which threats are not being captured, providing examples of how studies have managed dynamic timescales and mapped through to impacts, and provides key information for future conservation in Canada

Remote Sensing of the Aquatic Environments

The book highlights recent research efforts in the monitoring of aquatic districts with remote sensing observations and proximal sensing technology integrated with laboratory measurements. Optical satellite imagery gathered at spatial resolutions down to few meters has been used for quantitative estimations of harmful algal bloom extent and Chl-a mapping, as well as winds and currents from SAR acquisitions. The knowledge and understanding gained from this book can be used for the sustainable management of bodies of water across our planet

On The Chemical Nature of Aerosol, Clouds, and Precipitation along the US West Coast

Particulate matter (PM) in ambient air affects visibility, climate, human health, and the hydrological cycle. The water-soluble fraction of PM is relevant to nucleation efficiency, atmospheric residence time and hygroscopicity. In regions such as coastal California (United States) and Metro Manila (Philippines), pollution comes from variety of sources. By analyzing water-soluble element data collected in Marina, California from two separate summertime field campaigns: the Nucleation in California Experiment (NiCE) in 2013 and the Fog and Stratocumulus Evolution (FASE) campaign in 2016, six characteristic sources were found: Marine Emissions (45.4% of total mass), Secondary Aerosol (24.4%), Biomass Burning (13.1%), Waste Facilities (8.7%), Vehicular Emissions (4.4%) and Crustal Emissions (3.9%). Temporally-resolved results showed higher PM levels associated with Vehicular Emissions (day/night mass concentration ratio = 31.3) in Marina, California. Similar source apportionment analysis was conducted using data collected in Metro Manila, Philippines through a year-long sampling campaign (the Cloud, Aerosol, and Monsoon Processes Philippines Experiment (CAMP2Ex) weatHEr and CompoSition Monitoring (CHECSM) study) established in July 2018. It was observed that black carbon contributed a large fraction of PM in Metro Manila, exceeding what is found in most all other global regions. Positive Matrix Factorization (PMF) results revealed that the highest contribution to the study region was Aged/Transported pollution (48.0% of total mass) and followed by Sea Salt (22.5%), Combustion (18.7%), Vehicular/Resuspended Dust (5.6%) and Waste Processing (5.1%). In Metro Manila, secondarily produced inorganic species exhibited peaks in the submicrometer range (0.32–0.56 µm) while ions associated with primary emissions had peaks in the supermicrometer range (1.8–5.6 µm). Most of the water-soluble elements exhibited bimodal behavior, with peaks in the submicrometer and supermicrometer range. Pinnacles National Monument, ~65 km east of the coastline of California, is one of the few monitoring sites along the US western coast where aerosol and precipitation data are both available. At that site, seven pollution sources were identified by PMF: aged sea salt (25.7% of PM2.5), biomass burning (24.2% of PM2.5), fresh sea salt (8.2% of PM2.5), secondary sulfate (11.7% of PM2.5), dust (10.0% of PM2.5), vehicular emissions (8.2% of PM2.5) and secondary nitrate (5.2% of PM2.5). Examining co-located aerosol and precipitation data provided insights into aerosol and precipitation interactions. Results revealed that the reduction of pH in precipitation is likely due to uptake of HNO3 instead of acidic aerosols such as secondary sulfate and aged sea salt partitioning to rain drops. The positive correlation between Ca2+ in precipitation and two aerosol source factors (dust and aged sea salt) and PMCoarse indicated that coarse particles promoted precipitation to some extent. The finding that sulfate was highly corelated with dust and aged sea salt source factors, suggested that secondary sulfate partitions to dust and sea salt particles. Arid and semi-arid region such as Tucson, Arizona are experiencing water shortages, which promotes the development of advanced technologies that can improve process performance in water reclamation. UV/H2O2 advanced oxidation processes (AOPs) have been mostly used in destruction of organic compounds in tertiary wastewater treatment. The transformation mechanism of organic compound UV/H2O2 AOPs involves reaction with hydroxyl radical that is difficult to measure using analytical techniques. Existing models that have been developed to quantify and monitor the attenuation of organic compounds did not consider the scavenging effect between hydroxyl radical and reaction intermediates. In this study, a complete kinetic model was developed to understand the full reaction mechanism of p-cresol in UV/H2O2 AOPs. Such a model can be employed to predict concentrations of target compound and intermediates. Centrate is a supernatant of products produced in anaerobic digesters. Struvite is a relatively insoluble mineral that has been identified in sludge and anaerobic digestor associated pipelines. The formation of struvite clogs pipes and coats pumps and can significantly reduce process performance. Because the solubility of struvite is higher in low pH solution, carbon dioxide from an anaerobic digester was used to reduce pH of centrate for prevention of struvite formation. Bench experiments were conducted to validate an equilibrium model that was used to predict the steady state pH of centrate at the point of injection of carbon dioxide under atmospheric and elevated pressures. The equilibrium model was also used to determine pH, where struvite formation occurs. A pilot plant was constructed to investigate alternative operation modes. Results showed that mixing carbon dioxide pre-saturated centrate with a fresh centrate stream can reduce centrate pH to levels necessary to prevent struvite formation and is more effective than injection of gaseous carbon dioxide. This study provides a design protocol for wastewater treatment plants that experience struvite issues to implement proposed technologies for preventing struvite formation

Air Quality Research Using Remote Sensing

Air pollution is a worldwide environmental hazard that poses serious consequences not only for human health and the climate but also for agriculture, ecosystems, and cultural heritage, among other factors. According to the WHO, there are 8 million premature deaths every year as a result of exposure to ambient air pollution. In addition, more than 90% of the world’s population live in areas where the air quality is poor, exceeding the recommended limits. On the other hand, air pollution and the climate co-influence one another through complex physicochemical interactions in the atmosphere that alter the Earth’s energy balance and have implications for climate change and the air quality. It is important to measure specific atmospheric parameters and pollutant compound concentrations, monitor their variations, and analyze different scenarios with the aim of assessing the air pollution levels and developing early warning and forecast systems as a means of improving the air quality and safeguarding public health. Such measures can also form part of efforts to achieve a reduction in the number of air pollution casualties and mitigate climate change phenomena. This book contains contributions focusing on remote sensing techniques for evaluating air quality, including the use of in situ data, modeling approaches, and the synthesis of different instrumentations and techniques. The papers published in this book highlight the importance and relevance of air quality studies and the potential of remote sensing, particularly that conducted from Earth observation platforms, to shed light on this topic

Spinoff, 1994

This publication is intended to foster the aim of the NASA Technology Transfer Program by heightening awareness of the NASA technology available for reapplication and its potential for public benefit. The publication is organized in three main sections. The first section, Aerospace Aims, is an illustrated summary of NASA's major aeronautical and space programs, their goals and directions, their contributions to American scientific and technological growth, and their potential for practical benefit. The second section, Technology Twice Used, is a representative selection of new products and processes adapted from technology originally developed for NASA mainline programs, underlying the broad diversity of spinoff applications and the social/economic benefits they provide. The third section, Technology Transfer, is a description of the mechanisms employed to encourage and facilitate practical application of new technologies developed in the course of NASA activities