Aeolian sand transport over a wet, sandy beach

Abstract Quantifying aeolian transport within the intertidal zone is critical to understanding feedbacks between aeolian and nearshore processes in coastal environments. Here, we report a field study of aeolian transport over a wet bed in the intertidal zone. Predominate winds and beach orientation were aligned during all field observations. Mean grain size of bed samples were 0.18 mm and moisture content ranged from 16 to 17%. Velocity profiles were measured with a vertical array of cup anemometers. Sustained wind velocities were 9.5 m/s at 93 cm above the bed with gusts reaching 13.5 m/s. Five saltation traps captured particles in transport from the bed to a height of 15 cm. Particles in transport were wet and the highest moisture content of trapped sediments was found in the lowest saltation trap. Vertical flux profiles show a higher concentration of flux closer to the bed (81 to 89% below 5 cm) than those measured over dry beds. Power and exponential decay functions were fit to our vertical flux profiles; the exponential decay function best fit flux profiles with larger β coefficients and smaller α estimates than those fit to dry bed profiles. Total flux models predict transport below Belly's (1964) fluid threshold of motion for moist beds and model performance improves when using a threshold for dry sand. Our results suggest transport over wet beds is fundamentally different from transport over dry beds. However, more research is needed to discern the mechanics driving deviations in flux profiles over wet beds in field environments

Addressing the International Rip Current Health Hazard

Rip currents are concentrated seaward flows of water originating in the surf zone of beaches that are responsible for hundreds of injuries and fatal drownings worldwide annually. Calculating the exact number of deaths is hindered by logistical difficulties in collecting accurate incident reports, but the estimated annual average is about 59 in the United States (US), 53 in Costa Rica, and 21 in Australia. Previous research shows rip drownings are caused by a combination of personal and group behaviors with the physical environment. The co-incidence of a rip and swimmers, the ‘hazard,’ results from gaps in knowledge and in communication: we do not know how to accurately predict rip currents, and existing scientific understanding hasn’t fully infiltrated the practiced knowledge of the general public or policy makers designing beach access. This dissertation presents five papers examining the geophysical and social causes of rip-related deaths. Paper 1 reviews present rip current knowledge. Paper 2 demonstrates a novel method for mapping bathymetry within rip channels – topographic low spots in the nearshore resulting from feedback amongst waves, substrate, and antecedent bathymetry. The location and orientation of rip channels are investigated in Paper 3, which analyzes the degree of anisotropy in bathymetric surfaces. Paper 4 builds on rip detection by evaluating beachgoer knowledge alongside rip presence to evaluate physical environment control on swimmer exposure. Finally, because current research demonstrates lifeguard presence is a highly effective mitigation against drowning, Paper 5 identifies one way communities may fund beach lifeguard programs. Thus, the dissertation provides both cutting edge methods to improve prediction and warning systems with the geocomputation demonstrated in papers 2 and 3, and it provides more affordable short-term mitigation practices in papers 4 and 5, for increasing safety by designing and building geomorphologically informed beach access and funding lifeguard programs. As a whole, the dissertation evaluates both human and physical geographies of rip currents, a naturally occurring phenomenon that becomes hazardous when entered by vulnerable individuals. Results can inform policy makers of a range of rip fatality mitigation methods: developing frequent nearshore maps to observe rip channel behavior, automating the detection of rip channels, designing beach access controls informed by morphology, and funding lifeguard programs

Coupling of Backbarrier Shorelines to Geomorphological Processes

Recent evidence suggests that backbarrier structure may act as an historical record of island development, and that backbarrier shorelines can be used as a proxy of an island’s past and future transgressive response to sea-level rise. The structure and stability of back-barrier shorelines are dependent on the geologic framework, defined here as the combination of nearshore topography, underlying geology, and modern geomorphologic forces. This antecedent framework controls and influences the present morphology, nearshore dynamics, and rates of transgression in response to sea-level rise while also acting as a feedback to the estuary ecology on the bayside. It is therefore surprising that our understanding of backbarrier geomorphology is limited. There is a need for an established link between process regimes and an island’s geomorphological history. This thesis bridges the current intellectual gap. The primary hypothesis of this project is that shorelines and bathymetric isolines share quantitative shape signatures indicative of their shared morphological past. To establish this link, the backbarrier shorelines of four United States National Seashores (Fire Island, NY; Assateague Island, MD; Santa Rosa Island, FL; and North Padre Island, TX) are digitized from aerial imagery using the marshline as the shoreline indicator to ensure the inclusion of (vital, sometimes inundated) ecosystems and sediment storage. The alongshore variation of this backbarrier shoreline, the mainland shoreline, lagoon bathymetry, and nearshore bathymetry are each quantified through wavelet analysis and their shape signatures are examined for spatial correspondence. Large and small scale variations are identified and attributed to the geomorphologic controls operating on the same scale and alongshore variation. The result is an improved understanding of how the geologic framework controls backbarrier shoreline shape, which is essentially an expression of the underlying geology

Agile: From Software to Mission System

The Resource Prospector (RP) is an in-situ resource utilization (ISRU) technology demonstration mission, designed to search for volatiles at the Lunar South Pole. This is NASA's first near real time tele-operated rover on the Moon. The primary objective is to search for volatiles at one of the Lunar Poles. The combination of short mission duration, a solar powered rover, and the requirement to explore shadowed regions makes for an operationally challenging mission. To maximize efficiency and flexibility in Mission System design and thus to improve the performance and reliability of the resulting Mission System, we are tailoring Agile principles that we have used effectively in ground data system software development and applying those principles to the design of elements of the mission operations system

Collaborative Approaches to the Management of Geospatial Data Collections in Canadian Academic Libraries: A Historical Case Study

Special Issue: Geospatial Data Management, Curation, and Preservation - Part 2 The Ontario Council of University Libraries (OCUL) is a consortium of the twenty-one university libraries in Ontario, Canada. Since 1967, OCUL member institutions have worked together to share costs and workload through collective purchasing and licensing of information resources and more recently through the establishment of a shared digital infrastructure known as Scholars Portal. Under the auspices of OCUL, Ontario\u27s university map librarians formed the OCUL Map Group in 1973 to seek opportunities to communicate and collaborate to improve the collections and services they offer their users. The opportunities provided by collaboration have ensured a greater capacity to manage evolving collections of geospatial data. The group has served as a community of practice, which has provided educational opportunities and facilitated collaborative problem solving through a listserv, conference calls, and face-to-face meetings. This collegial environment has also led to the completion of a number of projects, which have resulted in the creation of new technical infrastructures and strategies for sharing the workload of data management tasks. This paper discusses the role of collaboration in OCUL projects and offers some suggestions for others considering embarking on collaborations of their own

Agile: From Software to Mission Systems

To maximize efficiency and flexibility in Mission Operations System (MOS) design, we are evolving principles from agile and lean methods for software, to the complete mission system. This allows for reduced operational risk at reduced cost, and achieves a more effective design through early integration of operations into mission system engineering and flight system design. The core principles are assessment of capability through demonstration, risk reduction through targeted experiments, early test and deployment, and maturation of processes and tools through use

Students Who Are the First Generation of Their Family to Attend College: A Comparative Study of Western Washington University Frosh

Executive Summary: Information for this report was obtained from a study conducted to determine the relative level of adjustment to college of first-generation and second-generation freshmen at Western Washington University. The study utilized the Student Adaptation to College Questionnaire (SACQ), a 67 item self-report adjustment measure. The SACQ is composed of a full-scale and four subscales: academic adjustment, social adjustment, personal-emotional adjustment, and attachment to the school the student is attending. The SACQ was administered to a randomly selected sample of 250 first and second- generation freshman students. Data analysis of survey results indicated that first-generation students do not measure significantly lower levels of adjustment than their peers. This finding is contrary to what would be expected from reviewing the current literature on the college experience of first-generation students. Literature suggest that first-generation students encounter a number of obstacles to college adjustment including a lack of emotional and financial support for college attendance, lower levels of academic preparation, and a lack of needed information about the college-going process. Findings from these studies indicate that such obstacles result in a lower degree of adjustment and thus a heightened risk of attrition. However, results of this current study indicate that literature findings do not apply to Western students at this time. Possible explanations proposed by this researcher for the discrepancy encountered between this study and others include the high quality entry qualifications possessed by Western freshmen due largely to the selectivity of the admissions process, a lack of cultural dissonance between the environment and values students encounter in the home, at high school, and at college due to the relative homogeneity of financial backgrounds, and the accessibility of support services which may enable first-generation students needing help to find someone to support them in the attainment of their educational goals

Perspectives on Astrophysics Based on Atomic, Molecular, and Optical (AMO) Techniques

About two generations ago, a large part of AMO science was dominated by experimental high energy collision studies and perturbative theoretical methods. Since then, AMO science has undergone a transition and is now dominated by quantum, ultracold, and ultrafast studies. But in the process, the field has passed over the complexity that lies between these two extremes. Most of the Universe resides in this intermediate region. We put forward that the next frontier for AMO science is to explore the AMO complexity that describes most of the Cosmos.Comment: White paper submission to the Decadal Assessment and Outlook Report on Atomic, Molecular, and Optical (AMO) Science (AMO 2020

LSST Science Book, Version 2.0

A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of the exciting science opportunities of the next decade. The Large Synoptic Survey Telescope (LSST) will have an effective aperture of 6.7 meters and an imaging camera with field of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over 20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a total point-source depth of r~27.5. The LSST Science Book describes the basic parameters of the LSST hardware, software, and observing plans. The book discusses educational and outreach opportunities, then goes on to describe a broad range of science that LSST will revolutionize: mapping the inner and outer Solar System, stellar populations in the Milky Way and nearby galaxies, the structure of the Milky Way disk and halo and other objects in the Local Volume, transient and variable objects both at low and high redshift, and the properties of normal and active galaxies at low and high redshift. It then turns to far-field cosmological topics, exploring properties of supernovae to z~1, strong and weak lensing, the large-scale distribution of galaxies and baryon oscillations, and how these different probes may be combined to constrain cosmological models and the physics of dark energy.Comment: 596 pages. Also available at full resolution at http://www.lsst.org/lsst/sciboo