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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,729 records · Page 96

Single-cell chromatin accessibility and cis -regulatory element analyses in plants using the scPlantReg platform

Understanding gene regulation is fundamental to plant improvement, but the lack of plant-specific single-cell assay for transposase-accessible chromatin using sequencing (scATAC-seq) frameworks and cross-species databases has limited insights into cell-type-specific cellular regulation. Here we present ‘scPlantReg’, an integrated framework and database for plant scATAC-seq data. scPlantReg supports end-to-end analyses from raw data processing to biological interpretation and features ‘scATACtor’, a supervised machine-learning approach that outperforms existing tools for cell-type annotation. We applied scPlantReg to pearl millet to characterize cell-type-specific chromatin accessibility and identify validated activating and repressing accessible chromatin regions (ACRs), revealing WRKY transcription factors as potential regulators of xylem development. Furthermore, we reanalysed scATAC-seq datasets from 8 plant species, spanning 11 tissues and multiple developmental stages, enabling cross-species comparisons. Furthermore, these analyses uncovered conserved regulatory programmes, including AP2/EREBP-associated ACRs linked to cell wall development and cell-type-conserved TFs across grasses. Collectively, scPlantReg provides a general framework and resource for comparative regulatory analysis in plants.

Epigenomics↗

Utah FORGE: Phase 2C Seismic Observation and Ground Water Well Data and Well Locations

This submission contains the following data associated with Utah FORGE Phase 2C within the Roosevelt Hot Springs geothermal area: - An ArcGIS shapefile with well locations for wells 58-32, 78-32, 68-32, OH-3, OH-4, WOW-2, and WOW-3. Well 58-32 is the deep test well, wells 68-32 and 78-32 are seismic test wells, and the OH and WOW wells were used for ground water monitoring and temperature gradient logging. - Drilling reports, lithologic logs, daily drilling reports, cuttings logs, and drilling photos for seismic monitoring wells 78-32 and 68-32. - Raw and post-processing temperature logs for wells OH-3, OH-4, WOW-2, and WOW-4. The archive also includes a README.txt file, which contains an explanation of the data and how it was acquired, and a text file with coordinates for the logged wells.

15 GEOTHERMAL ENERGY↗

Fabrication and Testing of CERMET Fuel Materials for Nuclear Thermal Propulsion

A first generation Nuclear Cryogenic Propulsion Stage (NCPS) based on Nuclear Thermal Propulsion (NTP) is currently being developed for Advanced Space Exploration Systems. The overall goal of the project is to address critical NTP technology challenges and programmatic issues to establish confidence in the affordability and viability of NTP systems. The current technology roadmap for NTP identifies the development of a robust fuel form as a critical near term need. The lack of a qualified nuclear fuel is a significant technical risk that will require a considerable fraction of program resources to mitigate. Due to these risks and the cost for qualification, the development and selection of a primary fuel must begin prior to Authority to Proceed (ATP) for a specific mission. The fuel development is a progressive approach to incrementally reduce risk, converge the fuel materials, and mature the design and fabrication process of the fuel element. A key objective of the current project is to advance the maturity of CERMET fuels. The work includes fuel processing development and characterization, fuel specimen hot hydrogen screening, and prototypic fuel element testing. Early fuel materials development is critical to help validate requirements and fuel performance. The purpose of this paper is to provide an overview and status of the work at Marshall Space Flight Center (MSFC).

Hickman, Robert↗

Climate Change Impacts and Adaptation for Dryland Farming Systems in Zimbabwe: A Stakeholder-Driven Integrated Multi-Model Assessment

Decision makers need accurate information to address climate variability and change and accelerate transformation to sustainability. A stakeholder-driven, science-based multi-model approach has been developed and used by the Agricultural Model Intercomparison and Improvement Project (AgMIP) to generate actionable information for adaptation planning processes. For a range of mid-century climate projections—likely to be hotter, drier, and more variable—contrasting future socio-economic scenarios (Representative Agricultural Pathways, RAPs) were co-developed with stakeholders to portray a sustainable development scenario and a rapid economic growth pathway. The unique characteristic of this application is the integration of a multi-modeling approach with stakeholder engagement to co-develop scenarios and adaptation strategies. Distribution of outcomes were simulated with climate, crop, livestock, and economic impact assessment models for smallholder crop livestock farmers in a typical dryland agro-ecological zone in Zimbabwe, characterized by low and erratic rainfall and nutrient depleted soils. Results showed that in Nkayi District, Western Zimbabwe, climate change would threaten most of the farms, and, in particular, those with large cattle herds due to feed shortages. Adaptation strategies that showed the most promise included diversification using legume production, soil fertility improvement, and investment in conducive market environments. The switch to more legumes in the farming systems reduced the vulnerability of the very poor as well as the more resourced farmers. Overall, the sustainable development scenario consistently addressed institutional failures and motivated productivity-enhancing, environmentally sound technologies and inclusive development approaches. This yielded more favorable outcomes than investment in quick economic wins from commercializing agriculture.

Climate change adaptation↗

Mars Mineral Spectroscopy Web Site: A Resource for Remote Planetary Spectroscopy

A web site dedicated to Mars Mineral Spectroscopy has been established at http://www.mtholyoke.edu/go/mars. Its goal is to provide an easily accessible data set of Mossbauer spectra of minerals collected over a range of temperatures, to provide suitable analog spectra for data acquired on remote surfaces such as Mars. Complementing these data (eventually) will be both reflectance FTIR data, collected at Brown University's RELAB facility, and Raman spectra to be collected by Jill Pasteris at Washington University St. Louis. Through our Education link, we provide information for those wishing to learn about how Mossbauer and other types of spectroscopy work. Our emphasis is to study only well-characterized mineral samples that represent typical rock-forming occurrences such as might exist on Mars and other terrestrial bodies in our solar system.

Dyar, M. D.↗

High-stress triaxial direct-shear fracturing of Utica shale and in situ X-ray microtomography with permeability measurement

The challenge of characterizing subsurface fluid flow has motivated extensive laboratory studies, yet fluid flow through rock specimens in which fractures are created and maintained at high-stress conditions remains underinvestigated at this time. The studies of this type that do exist do not include in situ fracture geometry measurements acquired at stressed conditions, which would be beneficial for interpreting the flow behavior. Therefore, this study investigates the apparent permeability induced by direct-shear fracture stimulation through Utica shale (a shale gas resource and potential caprock material) at high triaxial stress confinement and for the first time relates these values to simultaneously acquired in situ X-ray radiography and microtomography images. Change in fracture geometry and apparent permeability was also investigated at additional reduced stress states. Finite element and combined finite-discrete element modeling were used to evaluate the in situ observed fracturing process. Results from this study indicate that the increase in apparent permeability through fractures created at high-stress (22.2 MPa) was minimal relative to the intact rock (less than 1 order of magnitude increase), while fractures created at low stress (3.4 MPa) were significantly more permeable (2 to 4 orders of magnitude increase). Here, this study demonstrates the benefit of in situ X-ray observation coupled with apparent permeability measurement to analyze fracture creation in the subsurface. Our results show that the permeability induced by fractures through shale at high stress can be minor and therefore favorable in application to CO 2 sequestration caprock integrity but unfavorable for hydrocarbon recovery from unconventional reservoirs.

58 GEOSCIENCES↗

Deep Gaussian process-based cost-aware batch Bayesian optimization for complex materials design campaigns

The accelerating pace and expanding scope of materials discovery demand optimization frameworks that efficiently navigate vast design spaces with complex response surfaces while judiciously allocating limited evaluation resources. We present a cost-aware, batch Bayesian optimization scheme powered by deep Gaussian process (DGP) surrogates and a heterotopic querying strategy. Our DGP surrogate, formed by stacking GP layers, models complex hierarchical relationships among high-dimensional compositional features and captures correlations across multiple target properties, propagating uncertainty through successive layers. We integrate evaluation cost into an upper-confidence-bound acquisition extension, which, together with heterotopic querying, proposes small batches of candidates in parallel, balancing exploration of under-characterized regions with exploitation of high-mean, low-variance predictions across correlated properties. Applied to refractory high-entropy alloys for high-temperature applications, our framework converges to optimal formulations in fewer iterations with cost-aware queries than conventional GP-based BO, highlighting the value of deep, uncertainty-aware, cost-sensitive strategies in materials campaigns.

36 MATERIALS SCIENCE↗

Integrated End-to-end Performance Prediction and Diagnosis for Extreme Scientific Workflows

This report details recent progress for the ASCR funded project “Integrated End-to-end Performance Prediction and Diagnosis for Extreme Scientific Workflows”. We refer to the project as IPPD/2, reflecting the 2017 renewal under expanded scope and partners In IPPD/2, we increased our research scope to include data motion. We are focusing on three major aspects: a) observe how data is generated, distributed, and used; b) analyze how data is (repeatedly) consumed with a focus both on repeated patterns and anomalies; and c) explore how to optimize data motion. This new work on data motion will augment and complement IPPD/2’s research that focused on the computational aspects of tasks. We leverage and extend our existing tools and demonstrate our work on the Belle II workflow suite as well as on workflows from NSLS-II. The highlights of our work are as follows: Provenance for Workflows: Provenance is used to provide information enabling quality control, re-run computational workflows, and reproduce results. IPPD/2 has been building a scalable provenance management system that enables the capture of provenance from the high-level workflow through all relevant system levels in one integrated environment. Leveraging this work, our recent efforts have included using provenance as an enabling technique. Workload characterization: Leveraging provenance and analysis, we characterize data movement within network, storage, and memory over a variety of workloads. This characterization enables an understanding by performance analysts and application developers of the range of behaviors that could be expected. Performance Prediction for Workflows: The goal of modeling distributed workflows is to understand performance bottlenecks and enable more intelligent task scheduling to optimize selected metrics of interest (e.g., task throughput or output data rate). IPPD/2 has utilized both analytical and AI/ML modeling methodologies for performance modeling. Advanced Scheduling and Fault Modeling for Workflows: Scheduling of large-scale scientific workflows on geographically distributed resources is a challenging problem. To improve workflow throughput, we combined novel scheduling algorithms with task predictions from performance modeling and fault modeling. Dynamically Alleviating Bottlenecks in Workflows: Exploiting our provenance, analysis, and modeling efforts, we have explored and developed several techniques for dynamically detecting and alleviating bottlenecks in data movement. In particular, we have spent considerable effort demonstrating our techniques on production-like workflow configurations.

97 MATHEMATICS AND COMPUTING↗

Gaps in PV-Coupled Battery Modeling

With the rapid increase in battery attachment rates for PV systems and the continued qualification of storage for the ITC under OBBB, accurately characterizing PV-coupled batteries is becoming increasingly critical for the PV industry. This presentation will explore the key gaps in current best practices for modeling PV-coupled battery storage, including challenges such as battery thermal conditioning, the influence of dispatch strategies on battery value, the limitations of oversimplified degradation and performance models, and the absence of a centralized database containing sufficient battery parameters for accurate modeling. For behind-the-meter applications, we will also address issues like mismatched solar resource and load profiles, as well as uncertainties in future utility rates. Where applicable, we will quantify the impacts of these gaps on the accuracy and uncertainty of modeling efforts and highlight ongoing research aimed at addressing these challenges.

14 SOLAR ENERGY↗

NASA Goddard Giovanni Support for YOTC

The fundamental challenges to overcoming our shortcomings in understanding and modeling/predicting tropical convection have been twofold: I) the need to represent the broad range of scales applicable to the tropical organization problem (i.e. cumulus to planetary), and II) the lack of observations that adequately and simultaneously characterize this broad range of scales and that also provide three-dimensional information on thermodynamic, radiative and dynamical interactions, including cloud microphysical processes. In regards to the second challenge, it should be stressed that this problem will not be solved through the production and examination of one or a few high quality long-term records of fundamental quantities (e.g., SST, water vapor, cloud fraction). Rather, an alternative and more comprehensive paradigm is needed, one that integrates the multitude of applicable resources and measures of tropical convection in a manner that that can be better utilized by the diagnostic, modeling and forecasting communities to more completely and coherently focus on the problem.Because the goal of YOTC involves examining a scientifically complex, multi-scale process , rather than documenting the characteristics of a single parameter (e.g., SST, cloud cover), YOTC has an IOP perspective that targets a period, May 2008 April 2010, long enough to encompass many cases of tropical convection activity in many of its most challenging yet influential forms. This includes mesoscale and synoptic variability, easterly waves and hurricanes, convectively coupled waves, the MJO and the culmination of these in terms of the monsoon, their interactions with the extra-tropics, and mean characteristics such as tropical-to-subtropical transitions. The YOTC time period and length are driven in part by the following: 1) keeping the multi-sensor/multi-platform and model-analyses data sets and associated infrastructure manageable, 2) facilitating a focused effort by the research and operational communities on a specific scientific problem, and 3) capitalizing on the recent key additions to the armada of satellites (e.g., CloudSat and CALIPSO). The proposed dissemination framework for the YOTC satellite data archive is based on the Giovanni system. Giovanni is a web-based application developed by the NASA Goddard Earth Science (GES) Data and Information Service Center (DISC) that provides a simple and intuitive way to visualize, analyze, and access/download vast amounts of Earth science remote sensing data. A prototype YOTC Giovanni System (hereafter YOTC-GS) is in the process of being developed. YOTC-GS will provide access to level 2 (i.e. swath level data) and/or level 3 (i.e. gridded/mapped data) forms of satellite data, the choice or both depending on what is appropriate and relevant. The former is needed and better suited for detailed process examination, exploiting the highest temporal-spatial resolutions available and comparison to regional cloud-system resolving model / cloud resolving model (CSRM/CRM) model output. The latter is needed and more well suited for examination of phenomena, conditions and processes on large to global scales, and for comparisons to global model analyses, prediction and simulation output.

Ostrenga, Dana↗

Scientist-Guided Autonomy for Self-Reliant Rovers

Although Mars rover missions have been highly successful in accomplishing scientific objectives, mission productivity is limited by challenges stemming from the need for commanding ground-based targeted observations under communication constraints imposed by the large distance between Earth and Mars. With an aging fleet of sun-synchronous relay orbiters, the opportunities for regular communication with rovers may become even more limited. In addition to on-board planning, robust navigation, and health assessment, there are strategies to make future rovers more self-reliant by enabling them to perform autonomous scientific characterizations of new areas during periods without an opportunity for ground-based targeted observations. In particular, we have studied how a ”walkabout” strategy, in which an initial high-level characterization of a region is used to informed subsequent passes with specific targeted observations, was used successfully during the investigation of Pahrump Hills by the Mars Science Laboratory. Inspired by this approach, we have identified several capabilities that could allow a rover to autonomously perform some of these initial high-level characterization steps. In this paper, we describe technologies for identifying specific geologic units, regions, or features of interest, identifying areas of contact between two adjacent units, detecting and determining the orientation of layering within rock units, identifying novel and interesting features, and planning observations of regions with different sampling strategies using remote sensing instruments. The observations acquired with these approaches are driven by scientists’ guidance and can provide scientists with data to help inform their decisions about where to make more resource-intensive targeted observations.

Doran, Gary↗

Environmental licensing in Brazilian's crushed stone industries

Highlights: • Failures in environmental reporting compromise the effectiveness of the environmental license process • The infrastructure of environmental agencies must be improved • The participation of society is essential for monitoring industries - Abstract: The crushed stone industries' activities are characterized by the extraction and processing of stones for use as aggregates in construction. The sector causes environmental impacts that can be mitigated by the implementation of control instruments, namely, environmental licensing, whose purpose is to carry out monitoring of potentially polluting activities. In this paper, it was analyzed the environmental studies of three industries located in Monsenhor Gil, Piauí, Brazil, elaborated as requisites for obtaining the environmental and mineral licenses. There were made visits to the State Department of Environment and Water Resources (SEMAR) and to the National Department of Mineral Production (DNPM) to verify the environmental reports and the environmental and mineral licensing processes. There were also made visits to the analyzed industries, with the aim of comparing the information contained in the studies, with the reality and verifying the implementation of the mitigating measures proposed in them, through the observation of the industries operation, and interviews with the responsible managers. Furthermore, it was made a research in the scientific literature, to know the licensing process in other countries, to compare with the Brazilian reality. From the research, in Brazilian industries, it was observed that, although all the legal steps to obtain the licenses have been fulfilled, the environmental reports have elaboration failures, such as the lack of a multidisciplinary team and the fact that some data diverge from the reality, decreasing the reliability of the evaluation of the environmental impacts caused by the projects. Also, the environmental replacement cost is not accounted in the final value of the product, and any of the industries have started the implementation of the proposed mitigation measures since they do not have mineral depletion areas. SEMAR was delayed in issuing licenses within the period established by law, and there are no periodic inspections by both the environmental agency and DNPM. It should also be pointed out that the community did not claim public hearings and there is no participation in environmental education projects, factors that compromise the effectiveness of the environmental licensing process. Regarding the process in other parts of the world, in some countries, such as Uruguay and Paraguay, the agency responsible for licensing and inspection is federal. In Argentina, as in Brazil and USA, states have autonomy to legislate on environmental issues. There is also divergence in the period of execution of the licenses, being 12 months in Brazil, while in Thailand it can be up to 56 days. In Peru, the society participation is much more representative than in Brazil, and there is differentiation in the collection form of environmental compensation fees, among countries. The failures pointed out in the Brazilian process, as well as the system of other countries, can serve as parameters for the improvement of the process' effectiveness, both in Brazil and in other parts of the world, aiming at the conservation of the environment.

54 ENVIRONMENTAL SCIENCES↗

SiC MOSFET Based Modular Universal Power Electronics Regulator

A modular and scalable SiC MOSFET based universal power electronics regulator (UPER) allows coordinated integration of energy resources and loads, elimination of extra power conversion stages, and allowance of more sources or loads added with a simple plug and play feature. A comprehensive investigation has been conducted in term of the typical distributed generations and loads employed in buildings, in order to outline a detailed specification for UPER. Thus, a common DC bus voltage of 500 V and power rating of 3 kW are dedicatedly selected. The UPER hardware design and implementation are completely illustrated, including the static and dynamic characterization of the employed SiC MOSFET. The dedicated universal power cell and Plug-and-Play gate driver performs reliable continuous operation even exposed to an extreme fast switching speed (> 100 V/ns). The continuous operation of buck mode verified the UPER hardware development at 50 kHz with an overall efficiency of 98.19%. A new voltage polarity reversal phenomenon was also discovered in the verification of the isolated DAB stage with planar transformers.

Zheng, Sheng↗

AI-Enabled Discovery and Physics-Based Optimization of Energy Efficient Processing Strategies for Advanced Turbine Alloys (Final Technical Report)

In this project, the multi-organizational team of academic and industrial researchers from the University of Kentucky an aerospace and energy generation OEM partner has leveraged novel Digital Process Twin (DPT) models of process/structure interactions (i.e., process-induced surface integrity) to advance a paradigm of fully integrated computational materials engineering (ICME). Using efficient process models as the core of a digital process simulator for a reinforcement learning algorithm, the team has integrated industrial data and metrics of structure/performance/energy relationships and manufacturing-related energy metrics to optimize dynamic processing parameters for significantly improved life-cycle energy efficiency of advanced γ-TiAl low-pressure turbine (LPT) alloys, as indicated by a set of design relevant parameters (e.g., residual stresses and scrap rate). The key objective and anticipated outcome of the project was at least a 10% reduction in life-cycle embodied energy for a recently developed, γ-TiAl low-pressure turbine (LPT) alloy and nickel-based superalloy Inconel 718, through the adoption of the proposed AI-enabled process optimization approach. The final project outcomes significantly exceeded this original target, realizing manufacturing-related energy efficiency improvements of more than 130% for TiAl and up to 80% for Inconel 718. Rather than following the prevailing and highly inefficient empirical paradigm, the proposed study demonstrated the feasibility of adopting a digital, physics-based process design and optimization paradigm. The recurring need for manual intervention, rework, reinspection causes significant production bottlenecks and unnecessary expense associated with delivering the requisite component quality. The OEM partner, and turbine industry in general, expect to reap significant cost and resource savings if an AI-optimized set of parameters can be applied to specific machining operations. The technical scope of the proposed project involved the paving of a realistic path towards model-based and AI-enabled Integrated Computational Materials Engineering (ICME), and away from inefficient empirical process optimization and legacy manufacturing practices, which are no longer able to efficiently process novel high-performance turbine alloy materials. The project team will address the fundamental knowledge gap that currently exists within the ICME paradigm with respect to the process/structure/performance/energy impacts of finishing processes. While significant resources have been devoted to the ‘early stages’ of manufacturing, such as alloy design, primary and secondary processing, finishing processes have not been adequately integrated within ICME. To provide an actionable path towards model-based finishing process design (e.g., machining, burnishing, grinding, polishing), we will employ a novel AI-enabled process optimization paradigm, based on a computationally efficient, physics-based process simulator. Through limited experimental work to calibrate and validate our process simulator model via an advanced in-situ characterization technique and process optimization via reinforcement learning, the project will seek to demonstrate a viable alternative to the inefficient ‘legacy’ processing strategies, empirical testing and broad scope machining learning approaches, all of which fail to adequately consider complex process physics. The project team has identified an intermetallic γ-TiAl LPT alloy, which is currently being used as part of the OEM partner’s advanced gas turbine designs. This particular alloy poses significant manufacturing challenges during finishing operations, which limit the degree to which the current turbine design can be manufactured in an energy- and cost-efficient manner. Empirical testing and numerical modeling efforts to optimize processing parameters for γ-TiAl have not been able to resolve these manufacturing challenges, so the proposed physics-based AI-enabled optimization technology would offer a truly novel and transformative capability. The multi-organizational team of academic and industry experts from the UKY and the OEM partner will work together closely to demonstrate the analytical and experimental critical function and characteristic proof of concept of this novel approach.

20 FOSSIL-FUELED POWER PLANTS↗

Plant sulfate transporter protein sequences for phylogenetic analysis

Sulfur is an essential macronutrient that supports plant growth, development, and responses to environmental stress. Sulfate is the predominant inorganic form of sulfur in soils, and its uptake by roots and translocation to shoots are facilitated by the sulfate transporter (SULTR) family of proteins. Although the first plant SULTR gene was identified nearly three decades ago, several subfamily members, particularly those in the expansive and angiosperm-specific SULTR3 group, remain poorly characterized. To support comprehensive phylogenetic and sequence-based analyses, we compiled a curated dataset of 262 SULTR protein sequences from 22 plant species spanning the evolutionary breadth of land plants. This collection includes representatives from two basal lineages, two early-divergent angiosperms, six monocots, and ten dicots. All sequences were extracted from genome assemblies available in Phytozome v13 (Joint Genome Institute) and manually curated, with cross-referencing to additional databases such as NCBI when needed. This dataset provides a valuable resource for reconstructing the evolutionary history of the SULTR family, with particular emphasis on the diversification of SULTR3 transporters in flowering plants. This resource may also support functional annotation, comparative genomics, and structural modeling of sulfate transport proteins.

CBI↗

Basin and Petroleum System Modeling of Gas Hydrate Deposits in the Walker Ridge Area, Northern Gulf of Mexico - Poster

Poster presented by NETL at ICGH, 06/17 - Abstract:<p><br></p><p>We are currently constructing an Earth model of the Terrebonne Basin for comprehensive 3D modeling. Well data and a high-quality 3D seismic survey underpin the geologic conditions for the model. Additional model constraints include basal heat flow, seafloor temperature, and paleowater depth through time. Our initial investigation comprises the development of a “pseudo” 2D model centered on the deep WR313 #001 well. We are using this test case to establish the workflow for integrating BPSM with gas hydrate analyses; this will eventually be applied to the entire mini-basin. </p><p><br></p><p>A key aspect of investigating the gas hydrate system with BPSM is integrating it with the other active petroleum system(s) in the region, because the methane in hydrate deposits can derive from both biogenic and thermogenic sources. Some of the questions we may consider are: What is the history of these deposits with respect to the gas hydrate stability zone, recognizing that this area is not one characterized by simple continuous sedimentation and subsidence, but instead by periodic uplift, tilting, plate rotation, sea-level change, salt tectonics, and evolution of temperature gradients. </p><p><br></p><p>In conclusion, BPSM has been called the ‘great integrator’ in petroleum exploration. Development of a BPSM model of gas hydrates in the Terrebonne Basin of the northern GoM will provide a vehicle within which to integrate other early exploration and assessment research being conducted on gas hydrates, such as in frontier areas like Japan, as a potential resource likely to provide many decades of energy if proven to be commercially producible</p>

Dafov, Laura↗

Quantifying Uncertainties in Modeling Wind Resource Data from Different PBL Schemes in the WRF Model: A Case Study Over the Puerto Rico Region

This study examines the modeling uncertainty of wind resource data stemming from the use of various planetary boundary layer (PBL) parameterizations available in the Weather Research and Forecasting (WRF) model. WRF-based wind simulations spanning 20 years at 3-km resolution using 11 different PBL schemes are used to objectively investigate the uncertainty in modeling wind speed for land-based wind (LBW) and offshore wind (OSW) locations in Puerto Rico. The uncertainty in the wind modeling for the 20-year dataset is quantified using the spread index (SI) and standard deviation (SD). For virtual LBW and OSW sites, the SI and SD values are analyzed as calculated across various spatial and temporal scales. Because the PBL's atmospheric stability conditions can be characterized into two dominant categories, the study focuses on analyzing the SI and SD for daytime (mainly unstable PBL conditions) and nighttime (mainly stable PBL conditions). For wind shear (10 m-200 m) at the OSW and LBW sites, WRF-based numerical experiments indicate the following SI (or SD) ranges: 39%-94% (0.74 m/s-1.44 m/s) during the daytime for OSW, 50%-75% (0.68 m/s-1.19 m/s) during the daytime for LBW, 37%-60% (0.73 m/s-1.12 m/s) during the nighttime for OSW, and 57%-143 % (0.65 m/s-1.43 m/s) during the nighttime for LBW. While a high SI is observed when modeling LBW during the nighttime, there are notable modeling uncertainties during the daytime on the leeward side of the orographic barriers for Puerto Rico.

17 WIND ENERGY↗