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Tag: LIDAR
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  • Observations of Beach Change and Runup, and the Performance of Empirical Runup Parameterizations during Large Storm Events

    Abstract: Timeseries observations of beach elevation change and wave runup from a tower-mounted stationary lidar assess the skill of 2% runup exceedance (𝑅2%) estimates during four storm events at Duck, NC. The runup parameterization requires the foreshore beach slope, which generally unknown during high energy events. Pre-storm estimates are often used as a proxy. 𝑅2% hindcasts use the observed time-varying beach slope and a static pre-storm beach profile, yielding an 𝑅2% skill of 0.57. The skill drops to −1.0 using seasonal mean beach slopes and reduces after the peak of two storms with the appearance of beach cusps in the swash zone morphology. One storm’s runup is underpredicted by up to 1.0 m at high tides following the storm peak when cusps are present Additional pre- and post-storm mobile lidar surveys for one storm confirm ubiquitous small-scale beach cusps along 8 km of the local shoreline. The results suggest skillful runup estimates are often attainable given the availability of beach information before a storm. The parameterization errors increase when beach cusps develop, highlighting the need to extend standard one-dimensional runup parameterizations to account for two-dimensional effects.
  • What Lies Beneath

    Hovering over the calm waters of the lake, a strange device silently surveys every nook and cranny of the unseen depths. With laser beams dancing across the bottom, it paints an intricate drawing of data points revealing the lake’s mysteries. From the deepest depths to the sunny beaches, LiDAR’s watchful eye holds the key to unlocking a world beyond what the naked eye can perceive. A thrilling adventure awaits those who dare to decipher the language of light.
  • Total Water Level Controls on the Trajectory of Dune Toe Retreat

    Abstract: This study examines the trajectory (slope) of coastal foredune toe retreat in response to nine storm events that impacted the Outer Banks, North Carolina, USA. High resolution, three-dimensional, repeat mobile terrestrial lidar observations over a four kilometer stretch of coast were used to assess spatiotemporal beach and dune evolution at the storm timescale. Consistent with existing field observations from other sandy coastlines, an upward toe retreat was observed for most instances of dune retreat in the Outer Banks. However, these new topographic data indicate that the retreat can proceed steeply downward when the maximum total water level (TWL) defined by the 2% runup exceedance level is not high enough, for long enough, to erode the dune face. Non-linear relationships were found between the dune toe retreat trajectory as well as both the magnitude and duration of TWL above the dune toe, where instances of upward- and downward-directed retreat are best differentiated using the 7% runup exceedance level, rather than the commonly used 2% level. This physically justified non-linear relationship is shown to be consistent with observations from other studies, and could be a more effective parameterization for the retreat trajectory than those currently implemented in wave-impact dune erosion models.
  • CRREL researchers test new modular LiDAR tower, sensors

    The U.S. Army Engineer Research and Development Center’s Cold Regions Research and Engineering Laboratory’s (CRREL) Remote Sensing Geographic Information System Center of Expertise (RSGIS CX) is testing a newly engineered automated terrestrial laser scanning system (A-TLS) in Alaska.
  • ERDC Environmental Laboratory team receives prestigious technical achievement award

    A team from the U.S. Army Engineer Research and Development Center’s (ERDC) Environmental Laboratory (EL) recently received the Sebastian Sizgoric Technical Achievement Award from the Joint Airborne Lidar Bathymetry Technical Center of Expertise (JALBTCX) at their annual Coastal Mapping and Charting Workshop. The award recognizes any worldwide public or private contributor striving to advance the science of using light detection and ranging, or lidar, in coastal mapping and charting.
  • Continued Investigation of Thermal and Lidar Surveys of Building Infrastructure

    ABSTRACT: We conducted a combined lidar and thermal infrared survey from both ground-based and Unmanned Aerial System (UAS) platforms at McMurdo Station, Antarctica, in February 2020 to assess the building thermal envelope and infrastructure of the Crary Lab and the wet utility corridor (utilidor). These high-accuracy, coregistered data produced a 3-D model with assigned temperature values for measured surfaces, useful in identifying thermal anomalies and areas for potential improvements and for assessing building and utilidor infrastructure by locating and quantifying areas settlement and structural anomalies. The ground-based survey of the Crary Lab was similar to previous work performed by the team at both Palmer (2015) and South Pole (2017) Stations. The UAS platform focused on approximately 10,500 linear-feet of utilidor throughout McMurdo Station. The datasets of the two survey areas overlapped, allowing us to combine them into a single, georeferenced 3-D model of McMurdo Station. Coincident exterior temperature and atmospheric measurements and Global Navigation Satellite System real-time kinematic surveys provided further insights. Finally, we assessed the thermal envelope of the Crary Lab and the structural features of the utilidor. The resulting dataset is available for analysis and quantification.
  • Methodology for Remote Assessment of Pavement Distresses from Point Cloud Analysis

    Abstract: The ability to remotely assess road and airfield pavement condition is critical to dynamic basing, contingency deployment, convoy entry and sustainment, and post-attack reconnaissance. Current Army processes to evaluate surface condition are time-consuming and require Soldier presence. Recent developments in the area of photogrammetry and light detection and ranging (LiDAR) enable rapid generation of three-dimensional point cloud models of the pavement surface. Point clouds were generated from data collected on a series of asphalt, concrete, and unsurfaced pavements using ground- and aerial-based sensors. ERDC-developed algorithms automatically discretize the pavement surface into cross- and grid-based sections to identify physical surface distresses such as depressions, ruts, and cracks. Depressions can be sized from the point-to-point distances bounding each depression, and surface roughness is determined based on the point heights along a given cross section. Noted distresses are exported to a distress map file containing only the distress points and their locations for later visualization and quality control along with classification and quantification. Further research and automation into point cloud analysis is ongoing with the goal of enabling Soldiers with limited training the capability to rapidly assess pavement surface condition from a remote platform.
  • Using virtual solutions for robotic testing during the COVID-19 pandemic

    Researchers at the U.S. Army Engineer Research and Development Center (ERDC) are accustomed to finding unique and innovative approaches to solving today’s most challenging engineering problems. The current COVID-19 environment presented new obstacles for the Sensor Integration Branch (SIB) in the ERDC’s Information Technology Laboratory (ITL) and Environmental Processes Branch (CNE) in the ERDC’s Construction Engineering Research Laboratory, prompting the robotics group to capitalize on simulation software capabilities to meet mission requirements.
  • ERDC researchers developing low-cost, rapid watershed assessment

    Researchers from the U.S. Army Engineer Research and Development Center (ERDC) have partnered with the U.S. Army Corps of Engineers (USACE) Vicksburg District to develop and test a low-cost, rapid watershed assessment using remote sensing technology to evaluate problems associated with watershed instability including erosion, sedimentation, flooding and environmental degradation.
  • PUBLICATION NOTIFICATION: Coincidence Processing of Photon-Sensitive Mapping Lidar Data

     Link: http://dx.doi.org/10.21079/11681/35599 Report Number: ERDC/GRL TR-20-1Title: Coincidence