6 May 2025

Applications of the CRREL–-Geometric Optics Snow Radiative Transfer (GOSRT) Model: Incorporating Diffraction and Simulating Detection of Buried Targets

Abstract: Radiative transfer through a snow surface within the visible and near infrared (NIR) spectra is complicated by the shape, size, and configuration of the snow grains that comprise the snow surface. Ray-tracing and photon-tracking techniques combined with 3D renderings of snow resolved at the microscale have shown promise as a means to directly simulate radiative transfer through snow with no restrictions on the snow grain configuration. This report describes and evaluates the US Army Cold Regions Research and Engineering Laboratory (CRREL) Geometric Optics Snow Radiative Transfer (GOSRT) model. In particular, we describe the incorporation of the diffraction process into the photon-tracking framework and evaluate how accurately the model simulates the spectral albedo of targets buried within the snow. We find that the model simulated spectral albedo is little affected by the incorporation of diffraction for most applications. However, there are nonnegligible impacts on simulated albedo for small grains in the NIR due to a reduction in forward scattering. We conclude by recommending that diffraction is neglected in CRREL–GOSRT for most cases, as including it substantially increases the computational expense with minimal impacts on the result. Finally, we show that buried targets are only distinguishable for very shallow snowpacks.

5 May 2025

Assessing a Mobile Microgrid to Support Electric Vehicle Charging Stations on Army Installations

Abstract: Supplying reliable, off-grid power is critical for transitioning the Army’s fleet to zero carbon emitting vehicles. At the same time, vehicle charging and mission support equipment may require increased electrical loads than currently experienced at Army installations. Other decarbonization initiatives require clean sources of energy. Using microgrids powered with renewable electricity generation systems is a viable, independent solution for powering electric vehicles. Yet, there is a need to fill information gaps in the performance of these systems for realizing sustainable and resilient energy. The goal of this project was to increase the Army’s energy resilience by reducing reliance on the utility grid by using a compact and mobile microgrid that functions as an EV charging station. In this study, a trailered, mobile microgrid that integrates solar panels, a diesel generator, and batteries is evaluated based on performance under varying conditions. The energy generation capabilities are documented and evaluated for capabilities for powering electric vehicles. The outcomes of this research are the advancement of energy resiliency and the addition of performance in temperate and cold regions to the knowledge base. It is also anticipated this research may be leveraged to facilitate power independence and further support decarbonization efforts.

2 May 2025

Mobile Runway Edge Sheave Anchor Criteria in Asphalt Concrete Pavement

Abstract: The Mobile Runway Edge Sheave (MRES) is used in conjunction with the Mobile Aircraft Arresting System (MAAS) for setback aircraft arresting system (AAS) installations in expedient or temporary situations. There are existing criteria and tactics, techniques, and procedures (TTPs) for MRES installations on portland cement concrete (PCC) pavement and soil, but these criteria have not been developed for asphalt concrete (AC) pavements. The US Air Force Civil Engineer Center (AFCEC) tasked the US Army Engineer Research and Development Center (ERDC) to develop anchor criteria for the MRES in AC pavement and to perform full-scale load testing on the MRES to evaluate system response under representative loads. Three anchor stake layouts were evaluated under static and cyclic loading conditions: a 32-stake layout, a 16-stake layout, and an 8-stake layout. Elastic-plastic deflection data from the three test series were comparatively analyzed and show that the performance of the 16-stake layout was similar to that of the 32-stake layout for the given loading condition and pavement structure.

1 May 2025

Resilience: Directions for an Uncertain Future Following the COVID-19 Pandemic

Abstract: The concept of resilience is multi-faceted. This commentary builds upon the analytical distinctions of resilience provided by Urquiza et al. (2021, https://doi.org/10.1029/2020EF001508). In response to this article, we emphasize several distinctions between resilience and other systems concepts. These include distinctions between resilience, risk, and vulnerability, the tradeoff between resilience and efficiency, resilience contrasted with robustness, the relationship between resilience and sustainability, and finally methods for building resilience-by-design or resilience-by-intervention. Improving understanding of these concepts will enable planners to select resilience strategies that best support their system goals. We use examples from the 2020–2021 coronavirus pandemic to illustrate the concepts and the juxtapositions between them.

1 May 2025

Review of Stream Assessments for Evaluating Ecological Impacts and Benefits

Purpose: This technical note synthesizes common stream assessment methods and highlights their scope, data requirements, and ecological functions to assist practitioners and researchers in selecting appropriate tools for evaluating and managing stream ecosystem impacts and benefits.