NOAA Office of Coast Survey

Coast of Greenland-Swarte-huk-

Abstract Storm surge associated with tropical and extratropical cyclones has a long history of causing death and destruction along our coastlines. With more than 123 million people living in coastal shoreline areas and much of the densely populated Atlantic and Gulf coastal areas less than 10 ft (∼3 m) above mean sea level, the threat has never been greater. In this article, we summarize and integrate the most intensive series of studies completed to date on communication of storm surge risk. These were primarily geographically focused stakeholder surveys for evaluating the storm surge communication perceptions and preferences of forecasters, broadcast meteorologists, public officials, and members of the public—each a primary user group for storm surge forecasts. According to findings from seven surveys, each group strongly supports the National Weather Service (NWS) issuing watches and warnings for storm surge, whether associated with tropical cyclones (TC) or extratropical (ET) cyclones. We discuss results on public understanding of storm surge vulnerability, respondents’ preferences for separate storm surge information products, and initial assessments of potential storm surge warning text and graphics. Findings from the research reported here are being used to support relevant NWS decisions, including a storm surge watch and warning product that has been approved for use on an experimental basis in 2015 and the National Hurricane Center (NHC) issuance of local surge inundations maps on an experimental basis in 2014.

The democratization of ocean observation has the potential to add millions of observations every day. Though not a solution for all ocean monitoring needs, citizen scientists offer compelling examples showcasing their ability to augment and enhance traditional research and monitoring. Information they are providing is increasing the spatial and temporal frequency and duration of sampling; reducing time and labor costs for academic and government monitoring programs; providing hands-on STEM learning related to real-world issues; and increasing public awareness and support for the scientific process. Examples provided here demonstrate the wide range of people who are already dramatically reducing gaps in our global observing network while at the same time providing unique opportunities to meaningfully engage in ocean observing and the research and conservation it supports. While there are still challenges to overcome before widespread inclusion in projects requiring scientific rigor, the growing organization of international citizen science associations is helping to reduce barriers. The case studies described support the idea that citizen scientists should be part of an effective global strategy for a sustained, multidisciplinary and integrated observing system.

Analysis techniques are introduced that allow for estimation of potential sounding uncertainty due to water mass variability from reconnaissance campaigns in which oceanographic parameters are measured at a high temporal and spatial resolution. The analysis techniques do not require sounding data, thus analyses can be tailored to match any survey system; this allows for pre-analysis campaigns to optimize survey instrumentation and sound speed profiling rates such that a desired survey specification can be maintained. Additionally, the output of the analysis methods can potentially provide a higher fidelity estimation of sounding uncertainty due to water mass variability than uncertainty models in common use.

This paper presents an integrated digital methodology for the generalization of soundings. The input for the sounding generalization procedure is a high resolution Digital Terrain Model (DTM) and the output is a sounding data set appropriate for portrayal on harbour and approach Electronic Navigational Charts (ENCs). The sounding generalization procedure follows the “ladder approach” that is a requisite for the portrayal of soundings on nautical charts, i.e., any sounding portrayed on a smaller scale chart should also be depicted on larger scale charts. A rhomboidal fishnet is used as a supportive reference structure based on the cartographic guidance for soundings to display a rhombus pattern on nautical charts. The rhomboidal fishnet cell size is defined by the depth range and the compilation scale of the charted area. Generalization is based on a number of rules and constraints extracted from International Hydrographic Organization (IHO) standards, hydrographic offices’ best practices and the cartographic literature. The sounding generalization procedure can be implemented using basic geoprocessing functions available in the most commonly used Geographic Information System (GIS) environments. A case study was performed in the New York Lower Bay area based on a high resolution National Oceanic and Atmospheric Administration (NOAA) DTM. The method successfully produced generalized soundings for a number of Harbour and Approach nautical charts at 10 K, 20 K, 40 K and 80 K scales.

Generalization of nautical charts and electronic nautical charts (ENCs) is a critical process which aims at the safety of navigation and clear cartographic presentation. This paper elaborates on the problem of depth contours and coastline generalization—natural and artificial—for medium-scale charts (harbour and approach) taking into account International Hydrographic Organization (IHO) standards, hydrographic offices’ (HOs) best practices and cartographic literature. Additional factors considered are scale, depth, and seafloor characteristics. The proposed method for depth contour generalization utilizes contours created from high-resolution digital elevation models (DEMs) or those already portrayed on nautical charts. Moreover, it ensures consistency with generalized soundings. Regarding natural coastline generalization, the focus was on managing the resolution, while maintaining the shape, and on the islands. For the provision of a suitable generalization solution for the artificial shoreline, it was preprocessed in order to automatically recognize the shape of each structure as perceived by humans (e.g., a pier that looks like a T). The proposed generalization methodology is implemented with custom-developed routines utilizing standard geo-processing functions available in a geographic information system (GIS) environment and thus can be adopted by hydrographic agencies to support their ENC and nautical chart production. The methodology has been tested in the New York Lower Bay area in the U.S.A. Results have successfully delineated depth contours and coastline at scales 1:10 K, 1:20 K, 1:40 K and 1:80 K.

The nautical chart is one of the fundamental tools in navigation used by mariners to plan and safely execute voyages. Its compilation follows strict cartographic constraints with the most prominent being that of the safety. Thereby, the cartographer is called to make the selection of the bathymetric information for portrayal on charts in a way that, at any location, the expected water depth is not deeper than the source information. To validate the shoal-biased pattern of selection two standard tests are used, i.e. the triangle and edge tests. To date, some efforts have been made towards the automation of the triangle test, but the edge test has been largely ignored. In the context of research on a fully automated solution for the compilation of charts at different scales from the source information, this paper presents an algorithmic implementation of the two tests for the validation of selected soundings. Through a case study with real-world data, it presents the improved performance of the implementation near and within depth curves and coastlines and points out the importance of the edge test in the validation process. It also presents the, by definition, intrinsic limitation of the two tests as part of a fully automated solution and discusses the need for a new test that will complement or supersede the existing ones.

One of the most significant issues in hydrography today is the use of the ellipsoid as a vertical reference for surveying measurements. High-accuracy GPS is used to vertically position hydrographic data collection platforms, relating bathymetric observations directly to the ellipsoid. Models are used to translate those observations to another datum. The use of high-accuracy vertical GPS and translation models to replace traditional tidal correctors is relatively new to the hydrographic community and, as such, requires some discussion. Even though individual components of the process are well understood in their particular field, it is their amalgamation and application to hydrography that requires explanation, clarification and evaluation.Many hydrographic organizations around the world are using Global Navigation Satellite Systems (GNSS) derived heights in their data collection and processing stream. The International Federation of Surveyors (FIG) has recognized the importance of these new developments and has established a new working group under Commission 4, tasked to developing best practices for Ellipsoidally Referenced Surveys (ERS). Over twenty groups from academia, industry and government who are engaged in some form of ERS have provided the working group with a summary of their practices and experiences. This paper outlines the issues related to ERS and summarizes the solutions being employed.

Tidal datums are key components in NOAA’s Vertical Datum transformation project (VDatum), which enables effective vertical transformation of the water level between tidal, orthometric, and ellipsoid -based three-dimensional reference systems. An initial application of modeling tidal datums was developed for the coastal waters of Texas and western Louisiana in 2013. The goals of the current work include: (1) updating the tidal model by using the best available shoreline, bathymetry, and tide station data; (2) implementing a recently developed statistical interpolation method for interpolating modeled tidal datums and computing tidal datum uncertainties; and (3) using modeled tidal datums to upgrade non-tidal polygons for enhancing the quality of the VDatum marine grid population. The updated tidal model outperformed the previous tidal model in most cases. The statistical interpolation method is able to limit the interpolated tidal datums to within a user-defined model error (0.01 m in this work) and produce a spatially varying uncertainty field for each interpolated tidal datum field. The upgraded non-tidal polygons enhanced the quality of the VDatum marine grid population. This paper will introduce the detailed procedures of this modeling work, present and discuss the obtained results, share the effective methods used for improving model performance and lessons learned in the model assessments, and analyze the improvement of the current tidal model in comparison with the previous tidal model.

Bathymetric data are foundational for many important marine and coastal uses such as increasing the safety of navigation through updated high-resolution nautical charts and services, studying the changing of coastline features in response to climate change, creating hydrodynamic models for coastal resilience efforts, and studying marine life, among others. NOAA's Office of Coast Survey's National Bathymetric Source (NBS) program curates and regularly maintains a bathymetric data compilation for navigation, planning, and public needs. The traditional manual workflow of various disparate sources applied to a navigation product has been reimagined by leveraging automation in compiling sources using hydrographic quality metrics to determine the best available data for any geographic area. All bathymetric data sources acquired must be evaluated for depth, quality, and source information to make NBS data-driven workflows effective. The originating metadata informs the normalization of format, coordinate reference system, coverage, and quality assessment to prepare each source for compilation. The quality metrics used during the compilation phase to determine the best available bathymetry are carried through to the extracted products to inform effective use. The extracted bathymetry is prepared for navigation, planning, and public pipelines in customer-specific format, coordinate reference system, and resolution. All phases of the NBS workflow are discussed, from acquiring source through extracting bathymetry. The NBS program is driven to support the United States' bathymetry needs with timely, curated, and accessible bathymetric data.

Many coastal modeling applications rely on accurate bathymetry and/or topography data. The best data sets are often synthesized products with data collected from several sources which may be referenced to different vertical datums including Mean Low Water (MLW), Mean Lower Low Water (MLLW), North American Verical Datum of 1988 (NAVD 88), and others, depending on the age and source of the data. Transforming all of the data to a common vertical datum is a non-trivial problem, and so the National Ocean Service (NOS) of the National Oceanic and Atmospheric Administration (NOAA) has created a software tool called VDatum, which is designed to transform among approximately 30 vertical reference datums (including ellipsoidal, orthometric, and tidal datums). This program transforms among ellipsoidal datums using Helmert transformations, between the North American Datum of 1983 (NAD 83) (an ellipsoidal datum) and NAVD 88 (an orthometric datum) using a geoid model; between NAVD 88 and Mean Sea Level (MSL) using a topography of the sea surface model; and among tidal datums using tidal datum models. Regions where tidal datum models have been implemented include: Puget Sound and the Strait of Juan de Fuca, central California, southern coastal Louisiana, Lake Charles, Louisiana, Tampa Bay, the Outer Banks area in North Carolina, Delaware Bay, the New York Bight and Long Island Sound. A large collaboration of partners within NOS has participated to create this tool. The focus of this paper is on the work done in the Coast Survey Development Laboratory (CSDL) on the tidal datum modeling. Three types of models that have been employed to determine the tidal datum fields for the regional scale models are discussed: spatial interpolation of the datums, computation of the datums from a harmonic constant database, and computation of the datums from a regional hydrodynamic model. The results from these models are then interpolated onto the structured grid used with the VDatum software.

Current nautical chart generalization methods are notably labor intensive, requiring significant levels of human intervention to compile, update, and maintain chart products. The ideal situation would be a fully automated solution for generating nautical charts seamlessly from a comprehensive database, on demand, at the appropriate scale, at the point of use, and respecting the product constraints. However, regardless of the various research efforts and advancements in technology, including those involving AI, nautical chart generalization tasks are still performed manually, or semi-manually, where a likelihood of human error is expected. This manuscript presents a research effort toward automated chart compilation through scales. Nautical chart generalization guidelines are extracted, categorized, and translated into machine readable rules, utilized by a multi-agent model to perform the generalization of the source data to the target scale with no topological violations. This is illustrated in three testbeds for the most important ENC feature classes. While topology is maintained, the model utilizes readily available algorithms that, generally, compromise safety. Therefore, a custom validation tool detects safety violations for user intervention. The model has been made flexible to incorporate algorithms that align with application constraints, especially safety, as they become available.

ABSTRACT In this paper, we demonstrate the use of a new operational, unstructured-grid hydrodynamic model within the oil spill trajectory model GNOME (the General NOAA Operational Modeling Environment) to examine the transport of surface oil from a known source approximately 10 miles offshore of the Mississippi River Delta. At this location, a cluster of wells and/or contaminated sediments have been persistently leaking small amounts of oil since they were damaged in 2004. Slicks associated with this source are frequently detected in satellite imagery analysis, which indicates they are often oriented in the along isobath direction with typical dimensions of 0.5–2 km by 10–30 km varying with wind conditions. The Northern Gulf of Mexico Operation Forecast System (NGOFS) has recently been deployed by NOAA and includes this region. The underlying hydrodynamic model is an unstructured grid finite-volume model which allows variable grid resolution ranging from 10 km offshore to ~600 m near the coastline. Unstructured grid models are ideally suited for coastal areas as they allow flexible resolution to resolve complex bathymetry and coastlines. However, large model domains combined with high grid resolution can provide a challenge for operational trajectory models as sub-setting the model grid is not as straightforward as in the structured grid case. The utility of any hydrodynamic model for emergency response depends not only on its accuracy, but on the trajectory modeler's ability to access and use the information in a timely manner. As part of this study, we have developed tools to allow the NGOFS results (in addition to other unstructured grid models) to be readily available to GNOME users. Using output from the NGOFS in GNOME, a one year modeled simulation was run in which surface particles were released continuously from the location of the damaged wells. Predicted trajectories of modeled particles less than ~24-hours in age compare qualitatively well with the satellite observations.

(1873). Preliminary descriptions of new species of mollusks from the Northwest coast of America. Annals and Magazine of Natural History: Vol. 11, No. 62, pp. 159-160.

Abstract Over the continental slope off Oregon at the US West Coast, at 44.6°N, vertical stratification is found to be anomalously weak in July–August of 2014 and 2015 both in a regional ocean circulation model and conductivity–temperature–depth (CTD) profile observations. To understand the responsible mechanism, we focus on the layer between the isopycnal surfaces σ θ = 26.5 and 26.25 kg m −3 that is found between depths 100 and 300 m and represents material properties characteristic of the slope poleward undercurrent and shelf‐slope exchange. This layer thickness, about 50 m on average, can be twice as large during the above‐mentioned periods. In the 2009–2018 model analysis, this anomaly is revealed over the continental slope only in summers 2014 and 2015 and only off the Oregon and Washington coasts (40°–47°N). The stratification anomaly is explained as the effect of advection of the seasonal along‐slope potential vorticity (PV) gradient by an anomalously strong poleward slope current. In the annual cycle, the zone of strong along‐slope PV gradient is found between 40° and 47°N, supported by the local upwelling that results in the injection of the large PV in the bottom boundary layer over the shelf followed by its offshore transport in the slope region. The positive along‐slope current anomaly propagates to Oregon with coastally trapped waves as part of the El Niño oceanic response and can be up to 0.1 m s −1 . Advection by this anomalous poleward current results in transporting the seasonal PV gradient earlier in the season than on average.

Abstract. The compilation of Electronic Navigational Charts (ENCs) requires significant amount of time, labor-intensive efforts, and cost. Despite the advancements in technology and the various research efforts, generalization tasks are still performed manually or semi-manually with expected human errors. The dramatic increase in the amount of data that is collected by modern acquisition systems, in addition to the increasing timeline expected by the end-users, are constantly driving Hydrographic Offices (HOs) toward the investigation and adoption of more advanced and effective ways for automating the generalization tasks to speed up the process, minimize the cost, and improve productivity. Full automation of the nautical chart compilation process has been unreachable due to the strict nautical cartographic constraints (and particularly those of safety and topology) that pose a challenge for most of the available generalization tools, while it remains questionable whether automation can replace human thought processes. In this paper, we discuss a research effort for an Automated Nautical-chart Generalization (ANG) model in the Esri environment. The ANG model builds upon the nautical chart generalization guidelines and practice and utilizes available tools in the Esri environment to perform the generalization of selected ENC features to the target scale. Safety constraints in the marine domain is of utmost importance, however, since most of the readily available tools do not respect safety, the main goal of this effort has been an output with no topological violations. In the current phase of the project, we evaluate safety of soundings and contour for user fixing and while the validation of bathymetry is a well-researched topic, there was the need for an automated process to identify the sections of the generalized contours that have been displaced toward the shallow water side Therefore, this work also presents a safety validation tool that detects the contours’ safety violations in the output. The tool is composed of three main stages that run individually after the ANG model is complete with the aim to highlight the safety violations for fixing by cartographers.

The National Oceanic and Atmospheric Administration (NOAA) maintains the United States' suite of nautical charts, the coastal water level observation system, and the geodetic positioning reference system. NOAA charts are developed from NOAA's hydrographic and shoreline surveys, tide and current measurements, and national geographic positioning data, as well as information from other sources. NOAA's integrated suite of surveying, charting, water level, and positioning services is capable of increasing the efficient movement of goods while significantly reducing the risk of marine accidents and resulting environmental damage. NOAA is creating a database of digital vector chart data for the production of Electronic Navigational Charts (ENC). ENCs are being produced in the International Hydrographic Organization (IHO) format as defined in Edition 3.1 of Publication S-57: IHO Transfer Standard for Digital Hydrographic Data. ENCs are being compiled from original source materials where appropriate to provide the most accurate data available. The ENC database will be kept in continual maintenance (i.e., up-to-date on a weekly basis), allowing ENC users to obtain vector data sets that contain the most up-to-date and accurate information. NOAA is also offering the Physical Oceanographic Real-Time System (PORTS) in many major U.S. ports. PORTS is a program that supports safe and cost-efficient navigation by providing ship masters and pilots with accurate real-time information.

The present study simulated the barotropic tidal field in the Gulf of Maine (GOM) and adjacent waters using the ADvanced CIRCulation (ADCIRC) model. A high resolution model grid of 166,131 nodes and 308,259 elements was created to represent the water area up to the mean high water (MHW) coastline. The model run was forced with harmonics constants of nine tidal constituents (M2, S2, N2, K2, K1, P1, O1, Q1, and M4). Both tidal harmonic constants and tidal current ellipse parameters were analyzed using time series from a 32-day simulation. Tidal datum fields of mean higher high water (MHHW), MHW, mean low water (MLW), and mean lower low water (MLLW) were derived from simulated water level time series and validated/corrected using observational data. The M2 tidal constituent was investigated with respect to energy flux and dissipation. The present study identified two major energy flux pathways: one is a broad band with high intensity in the eastern GOM, spanning from Northeast Channel (NEC) up to the Bay of Fundy (BF), and the other displays as a closed gyre residing in the central/western GOM. The spatial distribution and depth dependence of energy dissipation were explored. Energy dissipation within 30–40 m bathymetry accounted for about 13% of the total M2 energy dissipated in the whole Gulf region.

An estimate of the effort needed to survey some arbitrary area is a critical part of the planning efforts of any hydrographic office. We develop a simple, analytic model to estimate full coverage of an arbitrary seafloor area based on a fixed angular swath system such as a multibeam echosounder. This model incorporates one tuneable parameter to account for the overall efficiency of survey execution. We had expected this parameter to be strongly tied to seafloor complexity and thus regionally consistent; it was not. In fact, we could discern no strong relationship between this parameter and any variable investigated, including region, roughness, variability, depth, or survey size. We use this tuned model, including an estimate of uncertainty, to develop a model for survey effort, and apply the model to all of the U.S. waters. Accounting for areas already surveyed to modern standards, we calculate that we have surveyed 44% of the U.S. waters to modern standards by area, but only 18% by level of effort. To survey the remaining area to modern standards would take 12 million linear nautical miles of survey, or approximately 177 years of a single platform running continuously at typical survey speeds.