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Earth System Model Aerosol-Cloud Diagnostics (ESMAC Diags) package, Version 2: Assessing aerosols, clouds and aerosol-cloud interactions via field campaign and long-term observations
WASHINGTON, Nov. 16 (TNSres) -- The U.S. Department of Energy's Pacific Northwest National Laboratory issued the following abstract of a journal article:
Evaluating Earth System Models (ESMs) with observations reveals shortcomings in these models and provides directions for future model improvements. However, most well-established diagnostics packages focus on large-scale features and climatology, while a comprehensive evaluation of aerosols, clouds, and aerosol-cloud interactions is needed to increase the confidence of process representations in the models. We developed an ESM aerosol-cloud diagnostics
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WASHINGTON, Nov. 16 (TNSres) -- The U.S. Department of Energy's Pacific Northwest National Laboratory issued the following abstract of a journal article:
Evaluating Earth System Models (ESMs) with observations reveals shortcomings in these models and provides directions for future model improvements. However, most well-established diagnostics packages focus on large-scale features and climatology, while a comprehensive evaluation of aerosols, clouds, and aerosol-cloud interactions is needed to increase the confidence of process representations in the models. We developed an ESM aerosol-cloud diagnosticspackage (ESMAC Diags) to facilitate routine evaluation of aerosols, clouds and aerosol-cloud interactions simulated by the Department of Energy's (DOE) Energy Exascale Earth System Model (E3SM), and this paper documents its version 2 functionality, which has substantial differences from ESMAC Diags version 1 (Tang et al., 2022a). ESMAC Diags v2 produces comparisons of simulated aerosol and cloud properties with in-situ and remote-sensing measurements from aircraft, ship, surface and satellite platforms. It currently includes six field campaigns and two permanent sites covering four geographical regions: Eastern North Atlantic, Central U.S., Northeastern Pacific and Southern Ocean, where frequent liquid or mixed-phase clouds are present and extensive measurements are available from the DOE Atmospheric Radiation Measurement (ARM) user facility and other agencies. ESMAC Diags v2 includes various types of single-variable and multi-variable diagnostics, such as percentiles, histograms, joint histograms and heatmaps, to assess aerosols, clouds, and aerosol-cloud interactions. A few examples are shown when evaluating E3SM version 2 (E3SMv2) using ESMAC Diags. Overall E3SMv2 qualitatively reproduces the observed aerosol and cloud properties, with quantitative biases in some variables such as aerosol particle and cloud droplet numbers and sizes. The coupling of aerosol and cloud number concentrations may be too strong in E3SMv2, possibly indicating a bias in processes that control aerosol activation. In addition, the liquid water path adjustment to perturbed cloud droplet number concentration behaves differently in E3SMv2 and observations, indicating a need for further improvements to cloud microphysics parameterization in E3SMv2.
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Original text here: https://www.pnnl.gov/publications/earth-system-model-aerosol-cloud-diagnostics-esmac-diags-package-version-2-assessing
Antecedent Hydrometeorological Conditions of Wildfire Occurrence in the Western U.S. in a Changing Climate
WASHINGTON, Nov. 15 (TNSres) -- The U.S. Department of Energy's Pacific Northwest National Laboratory issued the following abstract of a journal article:
Wildfires have significant hydrological and ecological impacts in the western U.S. Using a high-resolution regional climate simulation and wildfire observations for 1984-2018, this study investigates the antecedent hydrometeorological conditions (AHCs) of wildfires in the western U.S. During the warm season (April - September), the wildfire AHCs feature diverse surface pressure (PS), soil moisture (SM), and longwave/shortwave radiation (LW/SW)
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WASHINGTON, Nov. 15 (TNSres) -- The U.S. Department of Energy's Pacific Northwest National Laboratory issued the following abstract of a journal article:
Wildfires have significant hydrological and ecological impacts in the western U.S. Using a high-resolution regional climate simulation and wildfire observations for 1984-2018, this study investigates the antecedent hydrometeorological conditions (AHCs) of wildfires in the western U.S. During the warm season (April - September), the wildfire AHCs feature diverse surface pressure (PS), soil moisture (SM), and longwave/shortwave radiation (LW/SW)conditions. K-means clustering classifies wildfires into four types with distinct AHCs: low-PS-type and high-PS-type with lower and higher PS anomalies, respectively, LW-type featuring intense LW but weak SW anomalies, and wet-soil-type with wet soil anomalies. Each fire cluster represents 22%-27% of all the wildfires, featuring different combinations of climate and vegetation conditions and their diverse relations to regional hydrometeorological conditions, with wet-soil-type fires often exhibiting opposite correlations with AHCs compared to those of the other three types. In five major Koppen climate zones over the western US, type-based predictions improve the seasonal wildfire prediction accuracy (R2) by 10% compared to prediction without classification. Such improvement comes from separating the opposite relationships between wet-soil-type fires and seasonal AHCs from the other three types, along with separating LW-type fires, which include most of the lightning-ignited fires that occur more randomly. Increases in wildfire occurrence during 1984-2018 are dominated by the increases in the LW-type fires, while the wet-soil-type fires have decreased, consistent with the long-term drying in the western U.S.
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Original text here: https://www.pnnl.gov/publications/antecedent-hydrometeorological-conditions-wildfire-occurrence-western-us-changing
Advancing Radioactive Material Research Method: the Development of a Novel in situ Particle-attached Microfluidic Electrochemical Cell
WASHINGTON, Nov. 15 (TNSres) -- The U.S. Department of Energy's Pacific Northwest National Laboratory issued the following abstract of a journal article:
This work describes the development of a vacuum compatible microfluidic electrochemical cell (E-cell) for investigating the redox of uranium oxide (UO2). Conducting experiments on bulk amounts of radioactive material is costly and requires shielded hot cell facilities. By using microfluidic techniques, the amount of radioactive materials used in a single test can be significantly reduced, allowing for electrochemical experiments outside of a
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WASHINGTON, Nov. 15 (TNSres) -- The U.S. Department of Energy's Pacific Northwest National Laboratory issued the following abstract of a journal article:
This work describes the development of a vacuum compatible microfluidic electrochemical cell (E-cell) for investigating the redox of uranium oxide (UO2). Conducting experiments on bulk amounts of radioactive material is costly and requires shielded hot cell facilities. By using microfluidic techniques, the amount of radioactive materials used in a single test can be significantly reduced, allowing for electrochemical experiments outside of ashielded facility. The paper details several attempts to develop a microfluidic E-cell that uses UO2 as the working electrode and can be used for in situ chemical imaging analysis. The authors discuss the advantages of microfluidic E-cells over traditional electrochemical cells and the challenges of designing a microfluidic E-cell that uses solid material as a working electrode and is compatible with vacuum-based analytical instruments. The paper outlines the different methods proposed for attaching the UO2 electrode under a thin detection window of the E-cell, including Focused Ion Beam Scanning Electron Microscopy lift-out method, Au-coating attachment, and polyvinylidene fluoride (PVDF) binder method. The authors conclude that using PVDF binder method is the most effective approach and demonstrates that particle-based electrodes can provide an effective and low-cost solution for microfluidic electrochemical applications. The in situ microfluidic E-cell design with the integration of a radioactive material working electrode provides a promising and cost-effective approach for investigating spent nuclear fuel via reducing the amount of materials needed for analysis.
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Original text here: https://www.pnnl.gov/publications/advancing-radioactive-material-research-method-development-novel-situ-particle
Exploring sustainable electricity system development pathways in South America's MERCOSUR sub-region
WASHINGTON, Nov. 9 (TNSres) -- The U.S. Department of Energy's Pacific Northwest National Laboratory issued the following abstract of a journal article:
South America has abundant natural water and energy resources, and exploiting these resources to achieve a clean energy future is central to the continent's economic and sustainable development objectives for the next several decades. Designing pathways to achieving this clean energy future requires better understanding the structural, techno-economic, and policy forces that may influence the future development of the electricity sector in the
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WASHINGTON, Nov. 9 (TNSres) -- The U.S. Department of Energy's Pacific Northwest National Laboratory issued the following abstract of a journal article:
South America has abundant natural water and energy resources, and exploiting these resources to achieve a clean energy future is central to the continent's economic and sustainable development objectives for the next several decades. Designing pathways to achieving this clean energy future requires better understanding the structural, techno-economic, and policy forces that may influence the future development of the electricity sector in theregion. Here, we focus on an interconnected electricity system of five South American countries - Argentina, Brazil, Chile, Paraguay, and Uruguay - which represent major electricity generation, consumption, and trade dynamics in the region.
We explore the implications of various forces that could shape the future composition of the power sector in the sub-region, including: evolving renewable energy cost and performance, natural gas prices, cross-border interconnection facilities, early retirement of installed hydropower, and different decarbonization goals. We use a model framework based on a power system planning platform (GridPath) to co-optimize investment and operations of generation, storage, and transmission facilities out to 2050. Our results in a Reference scenario indicate that the electricity system can maintain a relatively clean energy portfolio by leveraging existing hydropower capacity and integrating increasingly cost-competitive wind and solar power. However, dependence on natural gas in the region is likely to remain high.
A low-carbon electricity system can cost-effectively be achieved through policy interventions (e.g., renewable portfolio standards) and by diversifying investments in wind, solar, battery storage, and some new hydropower capacity. We also find that existing hydropower is critical for maintaining reliable future grid operations. Enhanced regional electricity trade, mostly based on existing interconnection capacities with nominal investment in new transmission, can significantly benefit the clean energy transition in the region.
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Original text here: https://www.pnnl.gov/publications/exploring-sustainable-electricity-system-development-pathways-south-americas-mercosur
Data-Driven Control: Theory and Applications
WASHINGTON, Nov. 8 (TNSres) -- The U.S. Department of Energy's Pacific Northwest National Laboratory issued the following abstract of a journal article:
The ushering in of the big-data era, ably supported by exponential advances in computation, has provided new impetus to data-driven control in several engineering sectors. This topic's rapid and deep expansion has precipitated the need to showcase the highlights of data-driven approaches.
There has been a rich history of contributions from the control systems community in data-driven control. At the same time, several new concepts and research
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WASHINGTON, Nov. 8 (TNSres) -- The U.S. Department of Energy's Pacific Northwest National Laboratory issued the following abstract of a journal article:
The ushering in of the big-data era, ably supported by exponential advances in computation, has provided new impetus to data-driven control in several engineering sectors. This topic's rapid and deep expansion has precipitated the need to showcase the highlights of data-driven approaches.
There has been a rich history of contributions from the control systems community in data-driven control. At the same time, several new concepts and researchdirections have also been introduced in recent years.
Many of these contributions and concepts have started to transition from theory to practical applications. This paper will overview the historical contributions and highlight recent concepts and research directions.
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Original text here: https://www.pnnl.gov/publications/data-driven-control-theory-and-applications
Assessing Multi-Dimensional Impacts of Achieving Sustainability Goals by Projecting the Sustainable Agriculture Matrix into the Future
WASHINGTON, Nov. 8 (TNSres) -- The U.S. Department of Energy's Pacific Northwest National Laboratory issued the following abstract of a journal article:
The concept of sustainability inherently spans multiple spatial scales, sectors, variables, and time horizons. This study links a recently developed method of assessing present-day agricultural sustainability across environmental, economic, and social dimensions with a process-based integrated assessment model, in order to allow forward-looking analysis of sustainability by region and scenario.
The Sustainable Agriculture Matrix (SAM) estimates
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WASHINGTON, Nov. 8 (TNSres) -- The U.S. Department of Energy's Pacific Northwest National Laboratory issued the following abstract of a journal article:
The concept of sustainability inherently spans multiple spatial scales, sectors, variables, and time horizons. This study links a recently developed method of assessing present-day agricultural sustainability across environmental, economic, and social dimensions with a process-based integrated assessment model, in order to allow forward-looking analysis of sustainability by region and scenario.
The Sustainable Agriculture Matrix (SAM) estimatespresent-day agricultural sustainability at the national level using 18 indicator variables, of which this study estimates nine to the year 2100, using an enhanced version of the Global Change Analysis Model (GCAM). Scenarios include a reference scenario, and scenarios that apply the following measures, both individually and in combination, that are thought to improve sustainability: yield intensification, transition towards more plant-based ("flexitarian") diets, and economy-wide greenhouse gas emissions mitigation. The scenarios illustrate considerable complexity and tradeoffs inherent to efforts to improve agricultural sustainability in all regions globally. For example, yield intensification typically increases nitrogen pollution, flexitarian diets often reduce agricultural labor productivity, and greenhouse gas mitigation efforts may either increase deforestation or crowd out crop and livestock production due to consequent bioenergy demands.
However, there is considerable inter-regional heterogeneity in the responses, and the importance of such secondary responses also differs by region. The analysis and post-processing methods developed in this study allow quantification and visualization of the absolute and relative magnitude of the tradeoffs between agricultural sustainability indicator variables across regions, time periods, and scenarios.
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Original text here: https://www.pnnl.gov/publications/assessing-multi-dimensional-impacts-achieving-sustainability-goals-projecting
A sensitivity analysis of twinning crystal plasticity finite element model using single crystal and poly crystal Zircaloy
WASHINGTON, Nov. 8 (TNSres) -- The U.S. Department of Energy's Pacific Northwest National Laboratory issued the following abstract of a journal article:
The popularity of crystal plasticity finite element method (CPFEM) models is increasing due to their ability to predict the mechanical response of crystalline materials such as metals and metal alloys more accurately than traditional continuum mechanics models. Two main challenges faced by engineers and researchers while using CPFEM models are the need for large computational resources and the difficulty in calibrating a large number of material
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WASHINGTON, Nov. 8 (TNSres) -- The U.S. Department of Energy's Pacific Northwest National Laboratory issued the following abstract of a journal article:
The popularity of crystal plasticity finite element method (CPFEM) models is increasing due to their ability to predict the mechanical response of crystalline materials such as metals and metal alloys more accurately than traditional continuum mechanics models. Two main challenges faced by engineers and researchers while using CPFEM models are the need for large computational resources and the difficulty in calibrating a large number of materialparameters. In this paper, a CPFEM code is developed to include the twinning induced grain reorientation and subsequent crystallographic slip in these grains. Developed code is incorporated in a large-scale, parallelized nonlinear solver WARP3D.
A sensitivity analysis with respect to 22 material parameters was then conducted using single crystal and polycrystal Zircaloy RVE. Loading was applied along five different crystallographic orientations for single crystal RVE and along three directions namely, rolling (RD), transverse (TD), and normal (ND) direction for polycrystal RVE. Results obtained from the sensitivity analysis were used for the calibration of material parameters for Zircaloy. Finally, developed code along with calibrated material parameters was used to investigate the effect of the hydride phase formation in Zircaloy which is a typical case observed for nuclear applications. It was found that the volume fraction of the hydride phase has a significant impact on the mechanical properties of Zircaloy.
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Original text here: https://www.pnnl.gov/publications/sensitivity-analysis-twinning-crystal-plasticity-finite-element-model-using-single
