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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 325 records · Page 18
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Measured Moisture Performance of Sealed and Insulated Attics with Permeable Insulation In California Homes

This study performed detailed thermal and moisture measurements in two homes in Fresno and Clovis, California with sealed attics insulated with glass fiber insulation to determine moisture performance in inland California climates. Data were recorded once every minute for more than a year in each home to allow detailed observation of time-varying moisture and thermal conditions. Moisture measurements were taken at multiple locations in each attic and included wood moisture, surface condensation and surface relative humidity. The results showed that there are strong solar-driven diurnal cycles in attic wood and air moisture content, as well as longer-term seasonal and annual variations. Mold growth was obdserved on the North roof deck in one of the two homes even in this sunny dry climate with attics built in compliance with California building codes that specifically address sealed and insulated attics with vapor-permeable insulation. We investigated moisture stratification in the attic and found that, although there is stratification during sunny daytime hours, this was not when wood moisture content, surface humidity or surface condensation are high. Therefore, other moisture transport mechanisms are acting to increase moisture levels near the roof peak. Finally, our measurements also showed that the attic with the highest measured moisture levels did not have any mold growth, while mold was visually observed in the attic whose measurements indicted little or no concern, indicating that the state-of-the-art in moisture measurement and mold growth prediction in building assemblies may be insufficient.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2025

Assessing the impact of climate change on rainfall-triggered landslides: a case study in California

Landslides are widespread natural hazards which take a heavy toll on lives, property, and infrastructure each year. In January 2023 and 2024, widespread landslides occurred in California as a result of extreme winter precipitation. Estimating the regional evolution of landslide hazard in a changing climate is essential for adaptation planning and risk mitigation efforts. The complex effects of climate change on landslide hazard, however, are poorly understood. Here, we use climate and landslide observations to develop a novel data-driven approach for landslide susceptibility assessment under historical and future climate conditions. We apply this framework to investigate the evolution of landslide susceptibility in California and its impacts on the roadway system based on downscaled climate projections under moderate and high greenhouse gas emission scenarios. On average, the results indicate an increase in landslide susceptibility through 2100 in regions where historical susceptibility is moderate to very high. Although the spatio-temporal variations in landslide susceptibility are sensitive to climate model uncertainties in predicting extreme rainfall, the direst impacts are largely circumvented in lower emission scenarios.

Climate Change↗
DOE OSTI2025

A 30-yr high-resolution weather research and forecasting model downscaling data over California and Nevada

This dataset presents a 30-year high resolution meteorological dataset obtained using the WRF model (Advanced version Research WRF version 4.4). We used WRF and European Centre for Medium-Range Weather Forecasts Reanalysis v5 as initial and boundary conditions to generate gridded meteorological variables. A large number of surface weather stations was used for model validation. A multi-physics analysis was first developed to identify a good physics suite extended from 6 November 00 UTC to 10 November 23 UTC, 2018, which included the Camp Fire in northern California. Based on the best physics suite, the downscaling dataset extends from 1 December to 28 February, 1990–2021 and the horizontal domain has 1.5 km grid spacing covering the entire states of California and Nevada in the United States. Comparisons between hourly surface observations and WRF simulations of air temperature, relative humidity and wind speeds show mean absolute errors on the order of (1.6-2.0 C), (10 %) and 1.2–1.5 m s -1 , respectively.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2012

Transformation of Southern California's Residential Photovoltaics Market Through Third-Party Ownership

Third-party photovoltaics (PV) ownership is a rapidly growing market trend, where commercial companies own and operate customer-sited PV systems and lease PV equipment or sell PV electricity to the building occupant. Third-party PV companies can reduce or eliminate up-front adoption costs, reduce technology risk and complexity by monitoring system performance, and can repackage the PV value proposition by showing cost savings in the first month of ownership rather than payback times on the order of a decade. We find that the entrance of third-party business models in southern California residential PV markets has enticed a new demographic to adopt PV systems that is more highly correlated to younger, less affluent, and less educated populations than the demographics correlated to purchasing PV systems. By enticing new demographics to adopt PV, we find that third-party PV products are likely increasing total PV demand rather than gaining market share entirely at the expense of existing customer owned PV demand. We also find that mean population demographics are good predictors of third-party and customer owned PV adoption, and mean voting trends on California carbon policy (Proposition 23) are poor predictors of PV adoption.

14 SOLAR ENERGY↗
DOE OSTI2020

Stress-Drop and Source Scaling of the 2019 Ridgecrest, California, Earthquake Sequence

Stress drop, while difficult to measure reliably and at scale, is a key source parameter for understanding the earthquake rupture process and its relationship to strong ground motion. Here, we use a P-wave spectral decomposition approach, designed for large and densely sampled datasets, to measure earthquake stress drop in the region surrounding the 2019 Ridgecrest, California, earthquake sequence. With more than 11,000 measurements of earthquake stress drop in the 20-yr time period from 2000 through 2019, this dataset provides an opportunity to understand how coseismic stress changes and how other geophysical factors relate to the distribution of stress drop and its evolution in space and time. We observe a mild but persistent deviation from self-similar scaling, with larger events having systematically higher stress drops, though this trend depends on the assumption of an omega-square source spectral model. Earthquake stress drop increases with hypocentral depth in this study region, and the Ridgecrest aftershocks tend to have higher stress drops than the pre-event seismicity. This is in part due to their deeper hypocenters. Coherent spatial patterns of stress drop in the aftershock sequence correlate with the slip distribution of the M 7.1 mainshock, whose northwest rupture tip terminated in a long-lived zone of enervated stress drop. Although physical interpretation of these results is complicated by the trade-offs between the timing, depth, and location of these earthquakes, the observations provide new insight into the physics of the earthquake source in an area of renewed seismic activity in southern California.

58 GEOSCIENCES↗
DOE OSTI2015

Operational Benefits of Meeting California’s Energy Storage Targets

In October 2013, the California Public Utilities Commission (CPUC) issued rules for its jurisdictional utilities to procure a minimum of 1,325 megawatts (MW) of energy storage systems by 2020. The goal of this study is to examine the operational value of this storage portfolio in California and the rest of the Western Electricity Coordinating Council (WECC) region. Modeled results show that the storage portfolio, when providing energy and operating reserves, reduces the total WECC-wide production costs by $78 million per year in the 33% scenario. This value increases to $144 million per year in the 40% scenario, primarily because of the increase in off-peak and peak price differences that are due to additional solar generation. These values are equivalent to $59/kW-year for the storage portfolio for the 33% scenario and $109/kW-year for the 40% scenario.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2017

Transitioning the California Energy Commission Eligible Equipment List to a National Platform

The Energy Commission called on the National Renewable Energy Laboratory's (NREL)'s Solar Technical Assistance Team to explore various pathways for supporting continued evolution of the list. NREL staff utilized the Database of State Incentives for Renewables and Efficiency (DSIRE), California Solar Initiative (CSI) data, and information from in-depth interviews to better understand the impact of a lack of an updated list and suggest potential solutions. A total of 18 people from state energy offices, rebate program administrators, utilities, national testing laboratories, private companies, nonprofit organizations, and the federal government were interviewed between July and September 2013. CSI data were analyzed to illustrate the monetary benefits of the algorithm behind calculating performance of PV modules included on the list. The primary objectives of this study are to: 1) Determine the impact of not maintaining the list, and 2) Explore alternatives to the State of California's maintenance of the list.

14 SOLAR ENERGY↗
DOE OSTI2025

Photochemical and Cloud and Aerosol Aqueous Contributions to Regionally-Emitted Shipping and Biogenic Non-Sea-Salt Sulfate Aerosol in Coastal California

Aerosol nonsea-salt sulfate (NSS sulfate) forms in the atmosphere by secondary reactions of emissions from marine phytoplankton and shipping, with gas-phase as well as cloud and aerosol aqueous reactions controlling production. Twelve months of Atmospheric Radiation Measurements (ARM) during the Eastern Pacific Cloud Aerosol Precipitation Experiment (EPCAPE) at Scripps Pier in La Jolla, California, showed the highest NSS sulfate mass concentrations occurred for the northwesterly back-trajectories over 64% of the year, with an average of 0.90 μg/m 3 that contributed 76% of annual NSS sulfate concentration. Multiple Linear Regression (MLR) and a refractory black carbon tracer method attributed 76–80% of the regionally emitted sulfur dioxide (SO 2 ) sources of submicron NSS sulfate to marine biogenic emissions and 20–24% to shipping emissions. MLR for oxidation processes explained 21% of the variability with Downwelling Shortwave Radiation (DSW) driving photochemical reactions to account for 34% of annual regional sulfate production, Upwind Cloud Vertical Fraction (UCVF) controlling cloud-associated oxidation to account for 29%, and relative humidity (RH) describing aerosol-phase oxidation to account for 36%. NSS sulfate was correlated moderately to UCVF during April-June and August but to RH in October-January. These findings show the apportionment of SO 2 emissions to biogenic and shipping sources and provide observational constraints for the mechanisms for sulfate production from SO 2 in the atmosphere.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2026

Reduced legacy precipitation decreases microbial community growth efficiency and alters soil organic carbon in a California grassland

Changes in global patterns can leave a lasting legacy in semiarid grasslands by reshaping microbial growth dynamics and carbon cycling during the first wet-up in the autumn—a period known for intense microbial activity and significant carbon emissions. To study the lasting impacts of decreased winter rain, we implemented two precipitation regimes (100% vs. 50% mean annual precipitation) in California Mediterranean-climate grassland field plots. After the dry season, soils were rewetted in the laboratory with H 2 18 O and sampled at 0 h, 3 h, 24 h, 48 h, 72 h, and 168 h post rewet. We quantified CO 2 efflux, measured microbial growth and mortality via quantitative 18 O stable isotope probing and 16S rRNA gene amplicon sequencing, and characterized the soil organic carbon chemical composition, metagenomes, and metatranscriptomes.

16S gene amplicon sequencing↗
DOE OSTI2013

Estimating the Radiative Forcing of Carbonaceous Aerosols over California based on Satellite and Ground Observations

Carbonaceous aerosols have the potential to impact climate both through directly absorbing incoming solar radiation, and by indirectly affecting the cloud layer. To quantify this impact recent modeling studies have made great efforts to simulate both the spatial and temporal distribution of carbonaceous aerosols and their associated radiative forcing. This study makes the first observationally constrained assessment of the direct radiative forcing of carbonaceous aerosols at a regional scale over California. By exploiting multiple observations (including ground sites and satellites), we constructed the distribution of aerosol optical depths and aerosol absorption optical depths over California for a ten-year period (2000-2010). The total solar absorption was then partitioned into contributions from elemental carbon (EC), organic carbon (OC) and dust aerosols using a newly developed scheme. Aerosol absorption optical depth due to carbonaceous aerosols (EC and OC) at 440 nm is 50%-200% larger than natural dust, with EC contributing the bulk (70%-90%). Observationally constrained EC absorption agrees reasonably well with estimates from regional transport models, but the model underestimates the OC AAOD by at least 50%. We estimate that the TOA warming from carbonaceous aerosols is 0.7 W/m2 and the TOA forcing due to OC is close to zero. The atmospheric heating of carbonaceous aerosols is 2.2-2.9 W/m2, of which EC contributed about 80-90%. The atmospheric heating due to OC is estimated to be 0.1 to 0.4 W/m2, larger than model simulations. The surface brightening due to EC reduction over the last two decades is estimated to be 1.5-3.5 W/m2.

aerosols↗
DOE OSTI2020

Climatology of diablo winds in Northern California and their relationships with large-scale climate variabilities

The most destructive wildfires recently in Northern California have been linked to the occurrences of Diablo Winds (DWs). This study investigates the climatology of DWs during September–December 1979–2018, and their relationships with various climate modes using observations and two high-resolution reanalysis datasets. Our finding shows that DWs do not have a long-term trend in terms of the annual total number, total duration, and associated maximum wind speeds of DWs over the past 4 decades. However, their associated minimum relative humidity (RH) has decreased significantly, especially in October, which suggests that the dryness during DWs has become more severe with time, possibly leading to an increased chance of fires, and their destructive potential. We also find that the annual total number and duration of DWs have exhibited an quasi-periodic variation, with intervals ranging from 2 to 4 years. The periodic variability of DWs might be attributed to the teleconnections between DWs and climate oscillations, specifically the El Niño–Southern Oscillation (ENSO) and the quasi-biennial oscillation (QBO), through their modulation of pressure systems near California and the location of the Pacific jet stream. It is suggested that when La Niña and the QBO westerly phases co-occur in the spring, DWs in the following fall and winter tend to occur more frequently, and are associated with more intense high winds and dryness as compared to other springtime QBO and ENSO phases. This relationship may be used to predict the seasonal outlook of DWs.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2014

Effects of fine particulate matter and its constituents on low birth weight among full-term infants in California

Relationships between prenatal exposure to fine particles (PM{sub 2.5}) and birth weight have been observed previously. Few studies have investigated specific constituents of PM{sub 2.5}, which may identify sources and major contributors of risk. We examined the effects of trimester and full gestational prenatal exposures to PM{sub 2.5} mass and 23 PM{sub 2.5} constituents on birth weight among 646,296 term births in California between 2000 and 2006. We used linear and logistic regression models to assess associations between exposures and birth weight and risk of low birth weight (LBW; <2500 g), respectively. Models were adjusted for individual demographic characteristics, apparent temperature, month and year of birth, region, and socioeconomic indicators. Higher full gestational exposures to PM{sub 2.5} mass and several PM{sub 2.5} constituents were significantly associated with reductions in term birth weight. The largest reductions in birth weight were associated with exposure to vanadium, sulfur, sulfate, iron, elemental carbon, titanium, manganese, bromine, ammonium, zinc, and copper. Several of these PM{sub 2.5} constituents were associated with increased risk of term LBW. Reductions in birth weight were generally larger among younger mothers and varied by race/ethnicity. Exposure to specific constituents of PM{sub 2.5}, especially traffic-related particles, sulfur constituents, and metals, were associated with decreased birth weight in California. -- Highlights: • Examine full gestational and trimester fine particle and its constituents on term birth weight. • Fine particles and several of its constituents associated with birth weight reductions. • Largest reductions for traffic-related particles, sulfur constituents, and metals. • Greater birth weight reductions for younger mothers, and varied by race/ethnicity.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2014

Linking cases of illegal shootings of the endangered California condor using stable lead isotope analysis

Lead poisoning is preventing the recovery of the critically endangered California condor (Gymnogyps californianus) and lead isotope analyses have demonstrated that ingestion of spent lead ammunition is the principal source of lead poisoning in condors. Over an 8 month period in 2009, three lead-poisoned condors were independently presented with birdshot embedded in their tissues, evidencing they had been shot. No information connecting these illegal shooting events existed and the timing of the shooting(s) was unknown. Using lead concentration and stable lead isotope analyses of feathers, blood, and recovered birdshot, we observed that: i) lead isotope ratios of embedded shot from all three birds were measurably indistinguishable from each other, suggesting a common source; ii) lead exposure histories re-constructed from feather analysis suggested that the shooting(s) occurred within the same timeframe; and iii) two of the three condors were lead poisoned from a lead source isotopically indistinguishable from the embedded birdshot, implicating ingestion of this type of birdshot as the source of poisoning. One of the condors was subsequently lead poisoned the following year from ingestion of a lead buckshot (blood lead 556 µg/dL), illustrating that ingested shot possess a substantially greater lead poisoning risk compared to embedded shot retained in tissue (blood lead ∼20 µg/dL). To our knowledge, this is the first study to use lead isotopes as a tool to retrospectively link wildlife shooting events. - Highlights: • We conducted a case-based analysis of illegal shootings of California condors. • Blood and feather Pb isotopes were used to reconstruct the illegal shooting events. • Embedded birdshot from the three condors had the same Pb isotope ratios. • Feather and blood Pb isotopes indicated that the condors were shot in a common event. • Ingested shot causes substantially greater lead exposure compared to embedded shot.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Ambient temperature and added heat wave effects on hospitalizations in California from 1999 to 2009

Highlights: • We examined temperature and heat wave links to hospitalizations in California. • Heat waves set as minimum 2 days above climate zone- and month-specific threshold. • Temperature linked with many hospital visit types (e.g. diabetes, ischemic stroke). • Added heat wave associations observed (e.g. acute renal failure), but less often. • Associations sometimes differed by demographic and region. Investigators have examined how heat waves or incremental changes in temperature affect health outcomes, but few have examined both simultaneously. We utilized distributed lag nonlinear models (DLNM) to explore temperature associations and evaluate possible added heat wave effects on hospitalizations in 16 climate zones throughout California from May through October 1999–2009. We define heat waves as a period when daily mean temperatures were above the zone- and month-specific 95th percentile for at least two consecutive days. DLNMs were used to estimate climate zone-specific non-linear temperature and heat wave effects, which were then combined using random effects meta-analysis to produce an overall estimate for each. With higher temperatures, admissions for acute renal failure, appendicitis, dehydration, ischemic stroke, mental health, non-infectious enteritis, and primary diabetes were significantly increased, with added effects from heat waves observed for acute renal failure and dehydration. Higher temperatures also predicted statistically significant decreases in hypertension admissions, respiratory admissions, and respiratory diseases with secondary diagnoses of diabetes, though heat waves independently predicted an added increase in risk for both respiratory types. Our findings provide evidence that both heat wave and temperature exposures can exert effects independently.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Effects of polychlorinated biphenyls (PCB) on California sea lion (Zalophus californianus) lymphocyte functions upon in vitro exposure

Highlights: • PCBs induce immunomodulation of California sea lion lymphocytes. • Non dioxin-like PCBs stimulate sea lion lymphocyte proliferation at low concentrations. • Sea lion NK activity can increase under high levels of some non-dioxin PCB congeners. • PCB-induced modulation of sea lion lymphocytes can influence tumor progression. • Frozen lymph node mononuclear cells are viable for ecotoxicological analyses. Polychorinated biphenyl (PCB) congeners are a cause for concern due to their persistence in the environment, their lipophilic properties that cause them to bio-accumulate in top predators, and their adverse effects on mammalian health. For example, the common urogenital carcinoma reported in California sea lions (Zalophus californianus) (CSL) is associated with high tissue levels of PCBs, but the mechanisms responsible for this association are unknown. This study investigated the effect of exposure to six PCB congeners and a congener mix at low and environmentally relevant concentrations on NK cell-like and T cell activity using in vitro assays on cryopreserved lymph node mononuclear cells isolated from dead CSL. Non dioxin-like congeners 153 and 180 increased lymphocyte proliferation at 5 and 10 ppm, while congener 138 decreased proliferation by up to 43% at 15 ppm. Dioxin-like PCBs 118 and 169 did not affect lymphocyte proliferation, while the effects of congener 105 depended on the mitogen concentration; these did not correlate with their predicted toxic equivalent factors. NK cell-like activity was affected only by the highest concentration of PCBs tested; it was increased by non-dioxin-like congeners 138 and 153, and decreased by dioxin-like congener 169. The PCB congener mix suggested that the effects of PCB congeners were not simply additive. Our results concur with effects of PCBs reported for other pinniped's lymphocytes and add further experimental support to the observation that dioxin-like PCBs are not the most toxic congeners for marine mammals, contrary to effects in other species. This is the first evidence of in vitro suppression of NK cell-like cytotoxicity by a dioxin-like congener in a pinniped. More importantly, the observed results suggest that PCBs can modulate the CSL immune system, increasing exposed individuals’ susceptibility to viral and oncogenic challenges.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2017

Impact of California Computed Tomography Dose Legislation: Survey of Radiologists

Highly publicized accounts of radiation overdose from computed tomography (CT) in both children and adults prompted legislation in California regulating CT dose. The purpose of this study was to determine the impact of the law (codified in Senate Bill [SB] 1237) on California radiologist practice patterns and understanding of CT dose.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2018

The future of wind energy in California: Future projections with the Variable-Resolution CESM

Shifting wind patterns are an expected consequence of global climate change, with direct implications for wind energy production. However, wind is notoriously difficult to predict, and significant uncertainty remains in our understanding of climate change impacts on existing wind generation capacity. Historical and future wind climatology and associated capacity factors at five wind turbine sites in California are examined. Historical (1980–2000) and mid-century (2030–2050) simulations were produced using the Variable-Resolution Community Earth System Model (VR-CESM) to understand how these wind generation sites are expected to be impacted by climate change. A high-resolution statistically downscaled WRF product provided by DNV GL, reanalysis datasets MERRA-2, CFSR, NARR, and observational data were used for model validation and comparison. These projections suggest that wind power generation capacity throughout the state is expected to increase during the summer, and decrease during fall and winter, based on significant changes at several wind farm sites. Finally, this study improves the characterization of uncertainty around the magnitude and variability in space and time of California's wind resources in the near future, and also enhances our understanding of the physical mechanisms related to the trends in wind resource variability.

17 WIND ENERGY↗
DOE OSTI2010

Validation of the NSRDB-SUNY global horizontal irradiance in California

Satellite derived global horizontal solar irradiance (GHI) from the SUNY modeled dataset in the National Solar Radiation Database (NSRDB) was compared to measurements from 27 weather stations in California during the years 1998-2005. The statistics of spatial and temporal differences between the two datasets were analyzed and related to meteorological phenomena. Overall mean bias errors (MBE) of the NSRDB-SUNY indicated a GHI overprediction of 5%, which is smaller than the sensor accuracy of ground stations. However, at coastal sites, year-round systematic positive MBEs in the NSRDB-SUNY data up to 18% were observed and monthly MBEs increased up to 54% in the summer months during the morning. These differences were explained by a tendency for the NSRDB-SUNY model to overestimate GHI under cloudy conditions at the coast during summer mornings. A persistent positive evening MBE which was independent of site location and cloudiness occurred at all stations and was explained by an error in the time-shifting method applied in the NSRDB-SUNY. A correction method was derived for these two errors to improve the accuracy of the NSRDB-SUNY data in California. (author)

14 SOLAR ENERGY↗