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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 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Nationwide HVAC Energy-Saving Potential Quantification for Office Buildings with Occupant-Centric Controls in Various Climates

The occupant-centric control (OCC) is receiving an increasing attention due to its ability to reduce building heating ventilation and air-conditioning (HVAC) system energy consumptions while not affecting the occupant thermal comfort. This paper aims to investigate and quantify the nationwide energy-saving potential of implementing the occupant-centric HVAC controls in typical office buildings using a whole building simulation software EnergyPlus. First, the medium office and large office from the Department of Energy (DOE) Commercial Prototype Building Models (CBPM) were enhanced to have detailed layouts and dynamic occupancy schedules. Then, a comprehensive simulation plan was created by incorporating the multiple zone-level and system-level occupant-centric building HVAC controls recommended by the updated ASHRAE Standard 90.1 – 2019 and ASHRAE Guideline 36 – 2018. Three control scenarios with different occupancy sensing methods were identified in this simulation plan. A nation-wide parametric analysis which includes two building types, three occupancy sensing scenarios, two building code versions, and 16 U.S. climate zones was carried out. The simulation results of the key control variables and HVAC energy consumption suggest that generally, both the occupancy presence sensor and occupant counting sensor could achieve energy savings for the office buildings in majority of the scenarios. However, compared with the occupancy presence sensor, which could support both the temperature setpoint reset and operational breathing zone airflow rate reset for the unoccupied zones, the occupant counting sensor only brings a marginal benefit. Besides, a higher HVAC energy-saving ratio could be achieved in the heating-dominated zone, since the energy reduction brought with the minimum outdoor airflow rate reset is stronger in the heating mode.

Pang, Zhihong↗
DOE OSTI2024

The Influence of Climate Variability and Future Climate Change on Atlantic Hurricane Season Length

Abstract Atlantic hurricane season length is important for emergency management preparation, motivating the need to understand its variability and change. We investigated the influence of ocean variability on Atlantic hurricane season length in observations and a future climate simulated by the Energy Exascale Earth System Model (E3SM). We found that multiple factors influence hurricane season length, through their influence on season start and end. Warm western subtropical Atlantic sea‐surface temperature anomalies (SSTAs) during boreal spring (before the official hurricane season start) drive early starts to the hurricane season, and vice versa for cool SSTAs. Meanwhile, La Niña in autumn (before the official hurricane season end) drives late ends to the hurricane season, and vice versa for El Niño. E3SM projects a 27‐day increase in future Atlantic hurricane season length given La Niña and warm northern tropical Atlantic SSTAs. This research documents sources of predictability for Atlantic hurricane season length.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

Integration of urban science and urban climate adaptation research: opportunities to advance climate action

There is a growing recognition that responding to climate change necessitates urban adaptation. We sketch a transdisciplinary research effort, arguing that actionable research on urban adaptation needs to recognize the nature of cities as social networks embedded in physical space. Given the pace, scale and socioeconomic outcomes of urbanization in the Global South, the specificities and history of its cities must be central to the study of how well-known agglomeration effects can facilitate adaptation. The proposed effort calls for the co-creation of knowledge involving scientists and stakeholders, especially those historically excluded from the design and implementation of urban development policies.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Emergence of soil bacterial ecotypes along a climate gradient: Soil ecotypes along a climate gradient

The high diversity of soil bacteria is attributed to the spatial complexity of soil systems, where habitat heterogeneity promotes niche partitioning among bacterial taxa. This premise remains challenging to test, however, as it requires quantifying the traits of closely related soil bacteria and relating these traits to bacterial abundances and geographic distributions. In this work, we sought to investigate whether the widespread soil taxon Curtobacterium consists of multiple coexisting ecotypes with differential geographic distributions. We isolated Curtobacterium strains from six sites along a climate gradient and assayed four functional traits that may contribute to niche partitioning in leaf litter, the top layer of soil. Our results revealed that cultured isolates separated into fine-scale genetic clusters that reflected distinct suites of phenotypic traits, denoting the existence of multiple ecotypes. We then quantified the distribution of Curtobacterium by analysing metagenomic data collected across the gradient over 18 months. Six abundant ecotypes were observed with differential abundances along the gradient, suggesting fine-scale niche partitioning. However, we could not clearly explain observed geographic distributions of ecotypes by relating their traits to environmental variables. Thus, while we can resolve soil bacterial ecotypes, the traits delineating their distinct niches in the environment remain unclear.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2019

Temperature of the Troposphere [in State of the Climate in 2018]

The 2018 annual global lower troposphere temperature (LTT; surface to ~10km) ranked third to seventh highest as monitored by radiosondes since 1958 and satellites since 1979 according to nine datasets examined for this analysis. (As noted in Section 2b1, the 2018 global average surface temperature was fourth highest.) A weak La Niña event extending into early 2018 suppressed the global LTT in the 2018 boreal winter and spring. In comparison, the tropical Pacific exhibited higher-than-average temperatures in boreal autumn, indicating the eventual initiation of a weak El Niño at the end of 2018 that contributed to higher-than-average temperatures in the following seasons in 2019. Among the nine datasets, the 2018 anomaly ranged from +0.23°C to +0.47°C relative to the 1981–2010 average and was ~0.3°C lower than the record warm year of 2016.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Multi-Sectoral Urban Interactions: Fundamental Science Needs to Inform Pathways to More Resilient Communities in a Changing Climate Multi-Sectoral Urban Interactions: Fundamental Science Needs to Inform Pathways to More Resilient Communities in a Changing Climate

Urban areas and the supply networks that support their resource use are inherently multisectoral systems composed of infrastructural, environmental, and socio-institutional components. These systems are vulnerable to accelerating and interacting stresses from climate change, population growth, resource scarcity, and land-use pressure at the same time as they have a major influence on regional and global systems. For instance, a majority of the world’s greenhouse gas emissions, food consumption, and economic activity can be attributed to urban areas. Urban areas are highly heterogenous, both across and within cities in terms of their socio-demographic, environmental, and infrastructural characteristics. This heterogeneity shapes how urban systems interact and co-evolve and contributes to different economic, environmental, and health outcomes for communities within urban areas. Urban heterogeneity also generates differential vulnerabilities to stressors and differential capacity for adapting to change. The evolution of urban space is thus critical in shaping how human societies respond to global change as they seek to improve resilience to stressors, support prosperous and equitable communities, and use natural resources in a sustainable manner. Developing fundamental scientific understanding of urban heterogeneity and system interactions across sectors and scales is critical for mapping the resilience, sustainability, and equity implications of alternative future pathways. On July 2021 the MSD Urban Systems Working Group organized this workshop to provide a venue for coordination and identification of shared objectives, research themes, and major knowledge gaps, as well as developing a shared strategy for addressing these gaps. This report summarizes the outcomes of this workshop.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
NASA NTRS1977

The July climate and a comparison of the January and July climates simulated by the GISS general circulation model

Results are presented for a study directed to evaluate the ability of the global general circulation model of the Goddard Institute for Space Studies (GISS) in simulating seasonal differences as related to an experiment simulating the July climatology which parallels the January simulation presented by Somerville et al. (1974). The July and January simulations are compared with each other and with climatological data on seasonal changes, mainly for the Northern Hemisphere troposphere. The comparison shows that the model-generated energy cycle, distribution of winds, temperature, humidity and pressure, dynamical transports, diabatic heating, evaporation, precipitation and cloud cover are all realistic for the Northern Hemisphere troposphere in July. The model's simulation of seasonal differences is generally quite realistic since the systematic quantitative errors do not affect the simulation of relative changes, to first order. Defects that could seriously bias the model's performance in particular climate experiments are identified and discussed.

Stone, P. H.↗
NASA NTRS1980

Climate observing system studies: An element of the NASA Climate Research Program: Workshop report

Plans for NASA's efforts in climatology were discussed. Targets for a comprehensive observing system for the early 1990's were considered. A program to provide useful data in the near and mid-term, and a program to provide for a feasibility assessment of instruments and methods for the development of a long-term system were discussed. Climate parameters that cannot be measured from space were identified. Long-term calibration, intercomparison, standards, and ground truth were discussed.

Source record↗
NASA NTRS1979

Guidelines for the aerosol climatic effects special study: An element of the NASA climate research program

Research to help develop better understanding of the role of aerosols in the Earth's radiative balance is summarized. Natural volcanic injections of aerosols into the stratosphere to understand and model any resultant evidence of climate change are considered. The approach involves: (1) measurements from aircraft, balloon and ground based platforms which complement and enhance the aerosol information derived from satellite data; (2) development of instruments required for some of these measurements; (3) theoretical and laboratory work to aid in interpreting and utilizing space based and in situ data; and (4) preparation for and execution of concentrated observations of stratospheric aerosols following a future large volcanic eruption.

Source record↗
NASA NTRS1984

Climate studies with a multilayer energy balance model. III - Climatic impact of stratospheric volcanic aerosols

A multilayer energy balance model is applied in an examination of the sensitivity of climate to stratospheric aerosols induced by volcanic eruptions. Zonally and annually averaged quantities are considered, with ocean and land temperatures computed separately and the atmosphere below the 200 mb level divided into eight layers of 24 sublayers each. The aerosol is assumed to form in the 150-200 mb range. Aerosol parameters for radiative transfer calculations are reflection in the solar spectral region and absorption in the solar and IR regions. A 75 percent aqueous solution of sulfuric acid is assumed for the aerosols. The sensitivity of the hemispherically averaged surface temperature is enhanced 37 percent, with a 20 percent uncertainty, when the thermal IR radiation is excluded. The solar radiation enhances the surface temperatures to a higher degree than the thermal radiation. The maximum response to the evenly distributed aerosols is in the 60-70 deg N latitudes and propagates, weakening, to lower latitudes.

Chou, M.-D.↗
NASA NTRS1988

Dependence of warm and cold climate depiction on climate model resolution

Climate change simulations run with two different resolutions (8 deg by 10 deg and 4 deg by 5 deg) of the NASA Goddard Institute for Space Studies model are used to investigate radiative, dynamical, and regional sensitivities to model grid size. The results show that model resolution affected two key processes in the control runs, moist convection and the nonlinear transfer of kinetic energy into the zonal mean flow. It was found that the finer resolution model has more penetrative convection but less convection overall, with the results that its temperature and wind structure were altered with respect to the coarser grid model.

Rind, David↗
NASA NTRS1998

Global Studies of the Sulfur Cycle Including the Influence of DMS and Fossil Fuel Sulfur on Climate and Climate Change

The indirect effect of anthropogenic aerosols, wherein aerosol particles are thought to increase cloud droplet concentrations and cloud lifetime, is the most uncertain component of climate forcing over the past 100 years. Here, for the first time, we use a mechanistic treatment of droplet nucleation and a prognostic treatment of the number of cloud droplets to study the indirect aerosol effect from changes in carbonaceous and sulfate aerosols. Cloud droplet nucleation is parameterized as a function of total aerosol number concentration, updraft velocity and a shape parameter, which takes into account the mechanism, of sulfate aerosol formation, while cloud droplet number depends on the nucleation as well as on droplet sinks. Whereas previous treatments have predicted annual average indirect effects between -1 and -2 W/sq m, we obtain an indirect aerosol effect between -0.14 W/sq m and -0.42 W/sq m in the global mean.

Penner, Joyce E.↗
NASA NTRS1996

Projected Impact of Climate Change on the Water and Salt Budgets of the Arctic Ocean by a Global Climate Model

The annual flux of freshwater into the Arctic Ocean by the atmosphere and rivers is balanced by the export of sea ice and oceanic freshwater. Two 150-year simulations of a global climate model are used to examine how this balance might change if atmospheric greenhouse gases (GHGs) increase. Relative to the control, the last 50-year period of the GHG experiment indicates that the total inflow of water from the atmosphere and rivers increases by 10% primarily due to an increase in river discharge, the annual sea-ice export decreases by about half, the oceanic liquid water export increases, salinity decreases, sea-ice cover decreases, and the total mass and sea-surface height of the Arctic Ocean increase. The closed, compact, and multi-phased nature of the hydrologic cycle in the Arctic Ocean makes it an ideal test of water budgets that could be included in model intercomparisons.

Miller, James R.↗
NASA NTRS2003

SPARC-IGAC Symposium on Climate-Chemistry Interactions. Climate Feedback by Water Vapor in the Tropical Upper Troposphere

The strong greenhouse forcing by atmospheric water vapor is expected to play an important role in shaping the direction of any future changes in climate. We present calculations that provide a new perspective on the sensitivity of upper tropospheric water vapor to changes in surface temperature. Equilibrium states of our atmospheric model show unambiguously that as the surface warms, changes in the vertical distribution and temperature of detraining air parcels from tropical convection lead to higher water vapor mixing ratios in the upper troposphere. However, the increase in mixing ratio is not as large as the increase in saturation mixing ratio due to warmer environmental temperatures, so that the relative humidity decreases. Our analysis suggests that models that maintain a fixed relative humidity are likely overestimating the magnitude of the water vapor feedback.

Dessler, A. E.↗
NASA NTRS2005

Research on the Natural Variability of Climate and the Impact of Anthropogenic Forcing on Climate

The paper, "Latitude-dependent vertical mixing and the tropical thermocline in a global OGCM", was revised and published in Geophysical Research Letters. It treats the new GISS mixing scheme which includes the latitudinal dependence of the interior ocean turbulence field reported by Gregg, Sanford & Winkel. When implemented in the 3x3 degree NCAR CSMl OGCM [NCOMl] the new mixing scheme produces an improved, sharper equatorial thermoclines in both the Atlantic and the Pacific while simultaneously maintaining the realistic meridional overturning and northward heat transports found already with the previous GISS scheme. Also the paper "Diagnostics of the oceanic thermohaline circulation in a coupled climate model" describing earlier work on the grany was published.

Stone, Peter H.↗
NASA NTRS2008

The GEOS Chemistry Climate Model: Implications of Climate Feedbacks on Ozone Depletion and Recovery

The Goddard Earth Observing System Chemistry Climate Model (GEOS CCM) has been developed by combining the atmospheric chemistry and transport modules developed over the years at Goddard and the GEOS general circulation model, also developed at Goddard. The first version of the model was used in the CCMVal intercomparison exercises that contributed to the 2006 WMO/UNEP Ozone Assessment. The second version incorporates the updated version of the GCM (GEOS 5) and will be used for the next round of CCMVal evaluations and the 2010 Ozone Assessment. The third version, now under development, incorporates the combined stratosphere and troposphere chemistry package developed under the Global Modeling Initiative (GMI). We will show comparison to past observations that indicate that we represent the ozone trends over the past 30 years. We will also show the basic temperature, composition, and dynamical structure of the simulations. We will further show projections into the future. We will show results from an ensemble of transient and time-slice simulations, including simulations with fixed 1960 chlorine, simulations with a best guess scenario (Al), and simulations with extremely high chlorine loadings. We will discuss planned extensions of the model to include emission-based boundary conditions for both anthropogenic and biogenic compounds.

Stolarski, Richard S.↗
NASA NTRS2011

The Impact of Devegetated Dune Fields on North American Climate During the Late Medieval Climate Anomaly

During the Medieval Climate Anomaly, North America experienced severe droughts and widespread mobilization of dune fields that persisted for decades. We use an atmosphere general circulation model, forced by a tropical Pacific sea surface temperature reconstruction and changes in the land surface consistent with estimates of dune mobilization (conceptualized as partial devegetation), to investigate whether the devegetation could have exacerbated the medieval droughts. Presence of devegetated dunes in the model significantly increases surface temperatures, but has little impact on precipitation or drought severity, as defined by either the Palmer Drought Severity Index or the ratio of precipitation to potential evapotranspiration. Results are similar to recent studies of the 1930s Dust Bowl drought, suggesting bare soil associated with the dunes, in and of itself, is not sufficient to amplify droughts over North America.

Cook, B. I.↗