SEARCH · Search NASA

Results for “netting”

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.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 901 records · Page 50

All sources NASA NTRS DOE OSTI

DOE OSTI2019

Reticular chemistry in the rational synthesis of functional zirconium cluster-based MOFs

In the past two decades, reticular chemistry has developed into a powerful tool for the design and synthesis of porous, crystalline framework materials. The discovery of the first hexanuclear, zirconium cluster-based MOF (i.e. UiO-66; fcu net) led to a vast library of functional Zr-MOFs with various properties. The versatile connectivity of zirconium hexanuclear clusters and the adaptable tunability of organic ligands have resulted in the rational synthesis of a large set of Zr-MOFs based on edge-transitive nets; these nets commonly exists in crystalline network structures as suggested by reticular chemistry. In this review, we summarize recent advances in the synthesis of zirconium cluster-based MOFs in the light of reticular chemistry design principles. Isoreticular tuning of MOF parent structures and post-synthetic modification of Zr-MOFs for targeted applications are also deliberated.

Reticular chemistry↗

DOE OSTI2023

Influences on hydrogen production at a wind farm

If an affordable infrastructure for low-carbon-intensity hydrogen can be developed, then hydrogen is expected to become a key factor in decarbonizing the atmosphere. This research focuses on factors an existing wind farm operator would consider when weighing participating in the electricity market, the hydrogen market, or both. The solutions depend on the state of technology, which is changing rapidly, the local market structures, the local natural resources, and the local pre-existing infrastructure. Consequently, this investigation used an assessment approach that examined the variation of net present value. The investigation identified profitability conditions under three different scenarios: 1) Make and sell what makes economic sense at the time of production, 2) Use electrolyzer and fuel cell to consume power from the grid at times of low net demand and to produce electricity at times of high net demand, 3) Same as #2 but also market hydrogen directly when profitable.

08 HYDROGEN↗

DOE OSTI2022

Challenges and Opportunities in Decarbonizing the U.S. Energy System

The United States has pledged to develop a 100% carbon-free electric power system by 2035 and a net-zero-emissions economy by 2050. While important advancements have been made in the scale, performance, and economics of clean energy technologies, meeting the nation's ambitious goals will not only require their deployment at scale, but also additional innovation and effective integration of different solutions. Technological developments across the broad suite of low-carbon energy solutions are advancing rapidly, with ongoing innovations in renewable electricity generation, industrial processes, and energy-saving technologies and services, including LED lighting, induction heating, electric vehicles, energy storage solutions, and mobility as a service, plus smart devices, controls, and more efficient and smart buildings. Combining renewable electricity with biotic and abiotic pathways to produce chemicals, fuels, and materials promises to deliver new solutions. Grid-interactive buildings and communities, integrating transportation infrastructure and vehicles, are likely to be significant components of any zero-carbon energy strategy. Low-carbon industrial manufacturing will also make strong contributions to a net-zero economy. While the technical prospects appear promising, variations in the state of infrastructure, jurisdictional and social equity, pollution, economic and socio-cultural constraints, energy resource availability, and supply chain dynamics found in different locations present a range of challenges and demand customized solutions. This paper provides a critical review and offers new insights into the technical, infrastructure, analytic, political, and economic challenges faced in translating the nation's ambitious net-zero-emissions goals into feasible and reliable implementation action plans.

circular economy↗

DOE OSTI2017

Report on the Economic Optimization of a Demonstration Case for a Static N-R HES Configuration using RAVEN

The synthetic time history generation algorithm in RAVEN has been extensively tested and used to perform qualitative assessments of the statistical characteristics of the net demand vs. demand for different values of the penetration of wind generation. Reported results highlight the need to consider the impact of variable renewable on the electricity net demand profile, due to the increase in its volatility with increased wind penetration. This analysis provides a strong foundation for the modeling and simulation needs expressed under the "Nuclear-Renewable Hybrid Energy Systems" (NRHES) project. Following this confirmative analysis the entire stochastic optimization framework has been tested in a demo case. The case chosen is an optimization driven by profitability for a system composed by a nuclear plant and a hydrogen production industrial process. This type of economical analysis is aimed to assess the capability of a hybrid system to penetrate the current energy market. In this sense it differs from the approach suggested under NRHES, where a cost minimization approach is suggested. This analysis is instead aimed to show the flexibility of the developed framework, e.g. for the evaluation of retrofitting projects of already existing plants. The system considered is subject to variable prices of electricity, which are simulated using the algorithm for the production of synthetic time histories. The physical system is considered without inertia so that it can be replaced by dispatching rules based on the highest marginal profit. Two optimization problems have been considered, for the first the size of the nuclear power plant is fixed and the optimization variable is the capacity of the hydrogen production plant. For the second, both plant sizes are optimization parameters while the overall capital expenditure is caped. The economical figures of merits considered are the Internal Rate of Return (IRR) and/or Profitability Index (PI) for the first one (since no cap is placed on the investment size) and Net Present Value (NPV) and/or IRR for the second one where the capital expenditure is constrained. Economic input data concerning capital costs, size-scaling factors, and operational costs for both plants have been collected from literature in order to achieve a simulation as realistic as possible. More work will be needed to obtain even more realistic numbers, possibly from industrial partners, and considering market elasticity for the hydrogen market. In order to perform the optimization of the cases described above, the economical external RAVEN module (CashFlow) for financial analysis has been improved in flexibility and generality. Some improvements have also been made to the optimization algorithm for a more efficient treatment of the boundary constrains. In conclusion three major results have been obtained: a) collection of the economical parameters characterizing the nuclear power plants and hydrogen production plants, b) extension of the financial analysis module (CashFlow) to drive the calculation of all needed cash flow streams and c) the testing of the full framework in a nearly final configuration.

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2020

SPRUCE Photosynthesis and Respiration of Picea mariana and Larix laricina in SPRUCE Experimental Plots, 2016-2017

This dataset contains empirical physiological, morphological, and chemical data collected on two dominant conifer species, Picea mariana and Larix laricina, between May 2016 and August 2017 at the SPRUCE (Spruce and Peatland Responses Under Changing Environments) experimental site within the Marcell Experimental Forest in northern Minnesota, USA. Analyses assessed the response of conifers to whole-ecosystem warming and elevated atmospheric carbon dioxide (CO2) concentrations. Measurements include light-saturated net photosynthesis and dark respiration at ambient atmospheric carbon dioxide (CO2) concentration (2016), CO2 response curves of light-saturated net photosynthesis (2017), leaf morphology (leaf mass per unit leaf area) and nitrogen content (on both mass and area basis). Leaf photosynthesis and respiration were measured with portable photosynthesis systems (LI6400XT, LI6800, LI-COR Biosciences, USA). In 2016, photosynthesis and respiration were measured at a common temperature of 25 ˚C to assess thermal acclimation, and at growth temperatures (for each of the five treatment temperatures) to assess field performance. In 2017, CO2 response curves of net photosynthesis (so-called A-Ci curves) were conducted at different leaf temperatures (15, 25, 32.5, 40 and 45 ˚C) for assessment of biochemical parameters and their temperature sensitivity. In addition, dark respiration measurements at different leaf temperatures (10, 15, 20, 25, 30, 35, 40, and 45 ºC) were also taken. This dataset contains one data file in comma-separate values (*.csv) and Microsoft Excel (*.xlsx) format. Additional metadata are provided: a data dictionary and a file-level metadata file in comma-separate values (.csv) format and a user guide in PDF (*.pdf) format.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2016

NorthernStar Zero Energy Ready Homes

This is a repository for all NorthernSTAR Zero Energy Ready certified homes. Amaris Homes Model Home - St. Paul, MN 55110 Description: Model home completed September 2013 The DOE Zero Energy Ready Home Case Study looks to study and eventually design zero net energy homes in cold weather climates. These zero net energy homes are referred to as challenge homes. For this challenge home, Amaris Homes is working with the DOE in St. Paul, Minnesota. The household located at MN 55110 acts as the Amaris Challenge Home Test. The resources include technical drawings including siding, roofing and Windows. Christian Builders Challenge Home - House Count: 1 - Otsego, MN 55374 Need pictures from builder; This home actually narrowly missed certification under DOE Net Zero Energy Ready Homes. Need building plans and project summary from builder. DESIGN AND STRUCTURE - Amaris Homes - House Count: 7 Stillwater, MN 55082; Vadnais Heights, MN 55127; Bloomington, MN 55437; Apple Valley, MN 55124; White Bear Lake, MN 55110; Mounds View, MN 55112; Midland, MI 48642; DOE Zero Energy Ready Homes

Array↗

DOE OSTI2022

Towards Energy-Positive Buildings through a Quality-Matched Energy Flow Strategy

Current strategies for net-zero buildings favor envelopes with minimized aperture ratios and limiting of solar gains through reduced glazing transmittance and emissivity. This load-reduction approach precludes strategies that maximize on-site collection of solar energy, which could increase opportunities for net-zero electricity projects. To better leverage solar resources, a whole-building strategy is proposed, referred to as “Quality-Matched Energy Flows” (or Q-MEF): capturing, transforming, buffering, and transferring irradiance on a building’s envelope—and energy derived from it—into distributed end-uses. A mid-scale commercial building was modeled in three climates with a novel Building-Integrated, Transparent, Concentrating Photovoltaic and Thermal fenestration technology (BITCoPT), thermal storage and circulation at three temperature ranges, adsorption chillers, and auxiliary heat pumps. BITCoPT generated electricity and collected thermal energy at high efficiencies while transmitting diffuse light and mitigating excess gains and illuminance. The balance of systems satisfied cooling and heating demands. Relative to baselines with similar glazing ratios, net electricity use decreased 71% in a continental climate and 100% or more in hot-arid and subtropical-moderate climates. Total EUI decreased 35%, 83%, and 52%, and peak purchased electrical demands decreased up to 6%, 32%, and 20%, respectively (with no provisions for on-site electrical storage). Decreases in utility services costs were also noted. These results suggest that with further development of electrification the Q-MEF strategy could contribute to energy-positive behavior for projects with similar typology and climate profiles.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2023

AI-Based Optimal Design and Controls Can Greatly Reduce Carbon Emissions and Enhance Resilience in Residential Communities in Cold Climates

Net-zero energy residential communities are crucial for achieving decarbonization goals, but the high-penetration photovoltaic (PV) in those communities is posing challenges to the distribution grid. Traditional design and operation of net-zero communities rely on rule-of-thumb methods and may not work in complex scenarios. Artificial intelligence and machine learning methods can optimally size PV for net-zero energy, identify user preferences and usage patterns, and fully unlock the potential of distributed energy resources to address distribution grid issues.

artificial intelligence↗

DOE OSTI2016

Quantifying isentropic stratosphere-troposphere exchange of ozone

There is increased evidence that stratosphere-troposphere exchange (STE) of ozone has a significant impact on tropospheric chemistry and radiation. Traditional diagnostics of STE consider the ozone budget in the lowermost stratosphere (LMS) as a whole. However, this can only render the hemispherically integrated ozone flux and therefore does not distinguish the exchange of ozone into low latitudes from that into high latitudes. The exchange of ozone at different latitudes may have different tropospheric impacts. This present study extends the traditional approach from the entire LMS to individual isentropic layers in the LMS and therefore gives the meridional distribution of STE by the latitudes where each isentropic surface intersects the tropopause. The specified dynamics version of the Whole Atmosphere Community Climate Model is used to estimate the STE ozone flux on each isentropic surface. It is found that net troposphere-to-stratosphere ozone transport occurs in low latitudes along the 350–380 K isentropic surfaces and that net stratosphere-to-troposphere ozone transport takes place in the extratropics along the 280–350 K isentropes. Particularly, the seasonal cycle of extratropical STE ozone flux in the Northern Hemisphere displays a maximum in late spring and early summer, following the seasonal migration of the upper tropospheric jet and associated isentropic mixing. Moreover, differential diabatic heating and isentropic mixing tend to induce STE ozone fluxes in opposite directions, but the net effect results in a spatiotemporal pattern similar to the STE ozone flux associated with isentropic mixing.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2016

Testing a land model in ecosystem functional space via a comparison of observed and modeled ecosystem flux responses to precipitation regimes and associated stresses in a Central U.S. forest: Test Model in Ecosystem Functional Space

Testing complex land surface models has often proceeded by asking the question: does the model prediction agree with the observation? This approach has yet led to high-performance terrestrial models that meet the challenges of climate and ecological studies. Here we test the Community Land Model (CLM) by asking the question: does the model behave like an ecosystem? We pursue its answer by testing CLM in the ecosystem functional space (EFS) at the Missouri Ozark AmeriFlux (MOFLUX) forest site in the Central U.S., focusing on carbon and water flux responses to precipitation regimes and associated stresses. In the observed EFS, precipitation regimes and associated water and heat stresses controlled seasonal and interannual variations of net ecosystem exchange (NEE) of CO 2 and evapotranspiration in this deciduous forest ecosystem. Such controls were exerted more strongly by precipitation variability than by the total precipitation amount per se. A few simply constructed climate variability indices captured these controls, suggesting a high degree of potential predictability. While the interannual fluctuation in NEE was large, a net carbon sink was maintained even during an extreme drought year. Although CLM predicted seasonal and interanual variations in evapotranspiration reasonably well, its predictions of net carbon uptake were too small across the observed range of climate variability. Also, the model systematically underestimated the sensitivities of NEE and evapotranspiration to climate variability and overestimated the coupling strength between carbon and water fluxes. Its suspected that the modeled and observed trajectories of ecosystem fluxes did not overlap in the EFS and the model did not behave like the ecosystem it attempted to simulate. A definitive conclusion will require comprehensive parameter and structural sensitivity tests in a rigorous mathematical framework. We also suggest that future model improvements should focus on better representation and parameterization of process responses to environmental stresses and on more complete and robust representations of carbon-specific processes so that adequate responses to climate variability and a proper degree of coupling between carbon and water exchanges are captured.

58 GEOSCIENCES↗

DOE OSTI2016

Evapotranspiration of rubber ( Hevea brasiliensis ) cultivated at two plantation sites in Southeast Asia

The expansion of rubber (Hevea brasiliensis) cultivation to higher latitudes and higher elevations in southeast Asia is part of a dramatic shift in the direction of rural land cover change in the region toward more tree covered landscapes. To investigate the possible effects of increasing rubber cultivation in the region on ecosystem services including water cycling, eddy covariance towers were established to measure ecosystem fluxes within two rubber plantations, one each in Bueng Kan, northeastern Thailand, and Kampong Cham, central Cambodia. The results show that evapotranspiration (ET) at both sites is strongly related to variations in available energy and leaf area, and moderately controlled by soil moisture. Measured mean annual ET was 1128 and 1272 mm for the Thailand and Cambodia sites, respectively. After adjustment for energy closure, mean annual was estimated to be 1211 and 1459 mm yr at the Thailand and Cambodia sites, respectively. Based on these estimates and that of another site in Xishuangbanna, southwestern China, it appears that of rubber is higher than that of other tree dominated land covers in the region, including forest. While measurements by others in non rubber tropical ecosystems indicate that at high net radiation sites is at most only slightly higher than for sites with lower net radiation, mean annual rubber increases strongl with increasing net radiation across the three available rubber plantation observation sites. With the continued expansion of tree dominated land covers, including rubber cultivation, in southeast Asia, the possible association between commercially viable, fast growing tree crop species Giambelluca et al. Evapotranspiration of rubber (Havea brasiliensis) cultivated at two sites in southeast Asia and their relatively high water use raises concerns about potential effects on water and food security.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2017

Relationships between radiation, clouds, and convection during DYNAMO

In this paper, the relationships between radiation, clouds, and convection on an intraseasonal time scale are examined with data taken during the Dynamics of the Madden-Julian Oscillation (MJO) field campaign. Specifically, column-net, as well as vertical profiles of radiative heating rates, computed over Gan Island in the central Indian Ocean (IO) are used along with an objective analysis of large-scale fields to examine three MJO events that occurred during the 3 month period (October to December 2011) over this region. Longwave (LW) and shortwave radiative heating rates exhibit tilted structures, reflecting radiative effects associated with the prevalence of shallow cumulus during the dry, suppressed MJO phase followed by increasing deep convection leading into the active phase. As the convection builds going into the MJO active phase, there are increasingly top-heavy anomalous radiative heating rates while the column-net radiative cooling rate Q r progressively decreases. Temporal fluctuations in the cloud radiative forcing, being quite sensitive to changes in high cloudiness, are dominated by LW effects with an intraseasonal variation of ~0.4–0.6 K/d. While both the water vapor and cloud fields are inextricably linked, it appears that the tilted radiative structures are more related to water vapor effects. The intraseasonal variation of column-net radiative heating Q r enhances the convective signal in the mean by ~20% with a minimum in this enhancement ~10 days prior to peak MJO rainfall and maximum ~7 days after. Finally, this suggests that as MJO convective envelope weakens over the central IO, cloud-radiative feedbacks help maintain the mature MJO as it moves eastward.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2016

Ground heat flux: An analytical review of 6 models evaluated at 88 sites and globally

Uncertainty in ground heat flux (G) means that evaluation of the other terms in the surface energy balance (e.g., latent and sensible heat fluxes (LE and H)) remains problematic. Algorithms that calculate LE and H require available energy, the difference between net radiation, R NET , and G. There are a wide range of approaches to model G for large-scale applications, with a subsequent wide range of estimates and accuracies. Here, we provide the largest review of these methods to date (N = 6), evaluating modeled G against measured G from 88 FLUXNET sites. The instantaneous midday variability in G is best captured by models forced with net radiation, while models forced by temperature show the least error at both instantaneous and daily time scales. We produce global decadal data sets of G to illustrate regional and seasonal sensitivities, as well as uncertainty. Global model mean midmorning instantaneous G is highest during September, October, and November at 63.42 (±16.84) Wm -2 , while over December, January, and February G is lowest at 53.86 (±18.09) Wm -2 but shows greater intermodel uncertainty. Results from this work have the potential to improve evapotranspiration estimates and guide appropriate G model selection and development for various land uses.

58 GEOSCIENCES↗

DOE OSTI2018

Distinct Optoelectronic Signatures for Charge Transfer and Energy Transfer in Quantum Dot-MoS 2 Hybrid Photodetectors Revealed by Photocurrent Imaging Microscopy

Atomically thin transition metal dichalcogenides (TMDCs) have intriguing nanoscale properties like high charge mobility, photosensitivity, layer-thickness-dependent bandgap, and mechanical flexibility, which are all appealing for the development of next generation optoelectronic, catalytic, and sensory devices. Their atomically thin thickness, however, renders TMDCs poor absorptivity. For this study, bilayer MoS 2 is combined with core-only CdSe QDs and core/shell CdSe/ZnS QDs to obtain hybrids with increased light harvesting and exhibiting interfacial charge transfer (CT) and nonradiative energy transfer (NET), respectively. Field-effect transistors based on these hybrids and their responses to varying laser power and applied gate voltage are investigated with scanning photocurrent microscopy (SPCM) in view of their potential utilization in light harvesting and photodetector applications. CdSe–MoS 2 hybrids are found to exhibit encouraging properties for photodetectors, like high responsivity and fast on/off response under low light exposure while CdSe/ZnS–MoS 2 hybrids show enhanced charge carrier generation with increased light exposure, thus suitable for photovoltaics. While distinguishing optically between CT and NET in QD–TMDCs is nontrivial, it is found that they can be differentiated by SPCM as these two processes exhibit distinctive light-intensity dependencies: CT causes a photogating effect, decreasing the photocurrent response with increasing light power while NET increases the photocurrent response with increasing light power, opposite to CT case.

36 MATERIALS SCIENCE↗

DOE OSTI2026

Linking DSC/TGA to Cell Levels: Energetics, Evolved Gases, and Thermal Safety of NMC811‐Graphite Micro‐Cell

Thermochemical characterization of battery materials links intrinsic material properties to decomposition pathways, heat generation, and gas evolution that govern performance and safety. Despite extensive work on NMC811-Graphite, variability across partial configurations and the limited adoption of micro-cell architectures (cathode+anode+electrolyte+separator) hinder robust cell-scale interpretation. Accordingly, this work establishes a bottom-up, component-resolved methodology integrating DSC/TGA, evolved gas analysis (EGA), and in situ XRD to link decomposition pathways and energy release across partial and micro-cell configurations, providing a transferable assessment of safety and stability in emerging chemistries. In separator-free configurations, the gas–solid reaction between cathode-evolved O 2 and anode-leached Li dominates the net heat release (1139 J g −1 ). In contrast, in the micro-cell configuration, the separator hinders O 2 transport and alters the timing and pathways of other reactions, and reduces the net energy release to 618 J g −1 . Energy release was organized into defined temperature windows that provide a framework for a thermodynamic model combining quantified gas evolution with selected decomposition pathways and effective reaction enthalpies to estimate net specific energy release, with agreement between DSC and cell-level tests. Ex situ XPS of heat-treated samples extends post-mortem analysis to thermal-abuse regimes, supporting key pathway elements.

25 ENERGY STORAGE↗

DOE OSTI2016

Insights into cellulase-lignin non-specific binding revealed by computational redesign of the surface of green fluorescent protein

Biological-mediated conversion of pretreated lignocellulosic biomass to biofuels and biochemicals is a promising avenue towards energy sustainability. However, a critical impediment to the commercialization of cellulosic biofuel production is the high cost of cellulase enzymes needed to deconstruct biomass into fermentable sugars. One major factor driving cost is cellulase adsorption and inactivation in the presence of lignin, yet we currently have a poor understanding of the protein structure-function relationships driving this adsorption. In this work, we have systematically investigated the role of protein surface potential on lignin adsorption using a model monomeric fluorescent protein. We have designed and experimentally characterized 16 model protein variants spanning the physiological range of net charge (-24 to +16 total charges) and total charge density (0.28 to 0.40 charges per sequence length) typical for natural proteins. Protein designs were expressed, purified, and subjected to in silico and in vitro biophysical measurements to evaluate the relationship between protein surface potential and lignin adsorption properties. The designs were comparable to model fluorescent protein in terms of thermostability and heterologous expression yield, although the majority of the designs unexpectedly formed homodimers. Protein adsorption to lignin was studied at two different temperatures using Quartz Crystal Microbalance with Dissipation Monitoring and a subtractive mass balance assay. We found a weak correlation between protein net charge and protein-binding capacity to lignin. No other single characteristic, including apparent melting temperature and 2nd virial coefficient, showed correlation with lignin binding. Analysis of an unrelated cellulase dataset with mutations localized to a family I carbohydrate-binding module showed a similar correlation between net charge and lignin binding capacity. Altogether, our study provides strategies to identify highly active, low lignin-binding cellulases by either rational design or by computational screening genomic databases.

09 BIOMASS FUELS↗

DOE OSTI2020

Warming of alpine tundra enhances belowground production and shifts community towards resource acquisition traits

Abstract Climate warming is expected to stimulate plant growth in high‐elevation and high‐latitude ecosystems, significantly increasing aboveground net primary production (ANPP). However, the effects of simultaneous changes in temperature, snowmelt timing, and summer water availability on total net primary production (NPP)—and elucidation of both above‐ and belowground responses—remain an important area in need of further study. In particular, measures of belowground net primary productivity (BNPP) are required to understand whether ANPP changes reflect changes in allocation or are indicative of a whole plant NPP response. Further, plant functional traits provide a key way to scale from the individual plant to the community level and provide insight into drivers of NPP responses to environmental change. We used infrared heaters to warm an alpine plant community at Niwot Ridge, Colorado, and applied supplemental water to compensate for soil water loss induced by warming. We measured ANPP, BNPP, and leaf and root functional traits across treatments after 5 yr of continuous warming. Community‐level ANPP and total NPP (ANPP + BNPP) did not respond to heating or watering, but BNPP increased in response to heating. Heating decreased community‐level leaf dry matter content and increased total root length, indicating a shift in strategy from resource conservation to acquisition in response to warming. Water use efficiency (WUE) decreased with heating, suggesting alleviation of moisture constraints that may have enabled the plant community to increase productivity. Heating may have decreased WUE by melting snow earlier and creating more days early in the growing season with adequate soil moisture, but stimulated dry mass investment in roots as soils dried down later in the growing season. Overall, this study highlights how ANPP and BNPP responses to climate change can diverge, and encourages a closer examination of belowground processes, especially in alpine systems, where the majority of NPP occurs belowground.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2023

Spatial Bayesian models project shifts in suitable habitat for Pacific Northwest tree species under climate change

Abstract We developed spatial Bayesian hierarchical models to assess potential climate change impacts on suitable habitat for five important tree species in the Pacific northwestern United States (California, Oregon, and Washington). Individual‐species models were fit with presence–absence data from forest inventory field plots and spatial relationships were specified through a conditional autoregressive model. This modeling approach allowed us to visualize uncertainty in response curves, map current and future prediction uncertainty, and provide interval estimates for change. Upward elevational or northward latitudinal shifts in climatically suitable habitat were projected for all species. Climate change impacts were the most damaging for noble fir ( Abies procera ), for which 79%–100% of the current range was projected to become climatically unsuitable by the 2080s. Although coastal Douglas‐fir ( Pseudotsuga menziesii var. menziesii ) has been projected by others to gain habitat in Canada, within our study area we projected a net loss of climatically suitable habitat (ca. 8000–31,400 km 2 ) under three of four future climate scenarios. A net loss in habitat was also projected for Oregon white oak ( Quercus garryana ) under three of four scenarios, with 40%–60% of the current range becoming unsuitable. Although there was no net loss of habitat for forest land blue oak under any scenario, other factors like competition may inhibit blue oak ( Quercus douglasii ) and white oak from occupying areas projected to increase in climatic suitability. Additionally, between 13% and 32% of blue oak's current range was projected to become unsuitable; some of these areas aligned with dieback following the 2012–2015 California drought, which our data set predates. Unlike the other four species, we projected a 17%–25% increase in climatically suitable habitat for California black oak ( Quercus kelloggii ), although 1%–20% of the current range was still projected to become unsuitable. Our findings indicate that, although some species will face more pressure in tracking climatically suitable habitat than others, climate change will impact the location of suitable habitat for many species.

Kralicek, Karin↗