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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Enriched Background Isotope Study (EBIS): Analysis of 14C-Enriched Carbon Cycle in Soils and Litter at Forested Oak Ridge and AmeriFlux Sites, 2001-2011

These data provide a record of the multi-year, multi-institutional Enriched Background Isotope Studies (EBIS) projects that ran from 2000 through 2011. Elevated levels of 14C enriched CO2 in the air and soil atmosphere as well as leaf, stem, and root tissues were observed on the Oak Ridge Reservations (ORR) during the summer of 1999, and were attributed to local incinerator activities on and/or near the ORR (Trumbore et al. 2002). The isolated enrichment of the background levels of 14C in local forest ecosystem represented a unique opportunity to study unresolved carbon cycling processes such as the contribution of leaf versus root litter contributions to soil carbon accumulation, the rate of vertical transport of carbon into deep soil storage pools, and the differential contribution of physicochemical versus faunal driven processes to soil carbon cycling and sequestration. Leaf litter from the local enriched forest was transplanted to selected sites on the ORR and to selected AmeriFlux study sites to study soil C cycling across a range of soils and climates. The EBIS research projects provide data on C flux from litter sources to mineral soil sinks for United States eastern hardwood forests necessary for testing process hypotheses and judging efficacy of soil C cycling models. Experimental results from this study are being used to parameterize and refine existing carbon dynamics models, the quantification of the long-term fate of ecosystem carbon inputs and as a means to judge the potential for ecosystem carbon sequestration via enhance litter inputs to soil. EBIS observations support conclusions that intra- and inter-annual soil carbon cycling in hardwood forest soils should be characterized as a least a two-compartment system where surface leaf-litter and belowground root turnover represent primary carbon sources for organic-layer and mineral-soil carbon cycles, respectively. EBIS experiments were conducted to complete enriched litterfall maniplations in upland forests on Ultisol and Inceptisol soils of the Oak Ridge Reservation, Oak Ridge, Tennessee. We also collected additional14C-enriched materials for new experimental applications, and applied those materials to multiple AmeriFlux sites over a range of climatic, edaphic and biological conditions. The research provided data for addressing DOE's goal of understanding mechanisms controlling C flux, and for the improvement of models to be applied to policy discussions regarding the safe levels of greenhouse gases for the earth's system. There are 5 data files provided in comma separated (*.csv) format for vegetation, field litter, soil and air [C] and C isotope data from the EBIS studies and associated environmental data.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS2011

Incorporating Ameriflux Data into LVT

This paper describes a new generic data reader that was developed in Fortran to handle the Ameriflux data for the LIS Verification Toolkit (LVT). Researchers at the Hydrological Sciences Branch of NASA Goddard Space Flight Center have created a high resolution land surface modeling and data assimilation system known as the Land Information System (LIS), which provides an infrastructure to integrate state-of-the-art land surface models, data assimilation algorithms, observations of land surface from satellite and remotely sensed platforms to provide estimates of land surface conditions such as soil moisture, evaporation, snowpack and runoff. These model predictions are typically evaluated by comparing them with data from observational networks. The observational data; however, are usually available in disparate data formats and require significant effort to process them into a structure amenable for use with the model data. The motivation to develop a uniform approach for land surface verification as a way to alleviate these processing efforts has led to the development of LVT which is designed to enable the rapid evaluation of land surface modeling and analysis products from LIS. LVT focuses on the use of observational datasets in their native format. As the formats of these datasets vary widely, a major part of LVT is creating programs to read and process the native datasets. The primary goal of this project is to enhance LVT capabilities by incorporating observational datasets from Ameriflux

Georgiev, Teodor↗
DOE OSTI2022

A high spatial resolution land surface phenology dataset for AmeriFlux and NEON sites

Abstract Vegetation phenology is a key control on water, energy, and carbon fluxes in terrestrial ecosystems. Because vegetation canopies are heterogeneous, spatially explicit information related to seasonality in vegetation activity provides valuable information for studies that use eddy covariance measurements to study ecosystem function and land-atmosphere interactions. Here we present a land surface phenology (LSP) dataset derived at 3 m spatial resolution from PlanetScope imagery across a range of plant functional types and climates in North America. The dataset provides spatially explicit information related to the timing of phenophase changes such as the start, peak, and end of vegetation activity, along with vegetation index metrics and associated quality assurance flags for the growing seasons of 2017–2021 for 10 × 10 km windows centred over 104 eddy covariance towers at AmeriFlux and National Ecological Observatory Network (NEON) sites. These LSP data can be used to analyse processes controlling the seasonality of ecosystem-scale carbon, water, and energy fluxes, to evaluate predictions from land surface models, and to assess satellite-based LSP products.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2023

Earth System Model Simulations of Ameriflux sites using dynamic roots and dynamic leaf to root allocation

This data package contains point-scale Earth System Model simulations run with DOE's E3SM Model. The package includes four sets of simulations, one set of simulations run in the default configuration, a second set of simulations run with the dynamic root module enabled, the third set with dynamic leaf to fine root allocation, and the fourth with the combination of dynamic roots and dynamic allocation. These simulations were run in point mode a Ameriflux sites, US-MMS, US-Moz, US-Syv, and US-NR1. These datasets can be used to assess the impact that dynamic roots have on Land Surface fluxes such as carbon and water. The simulations were run with atmospheric forcing from the Global Soil Wetness Project. We provide specifically here Gross Primary Production, Transpiration, relative root fraction per soil layer as well as Air Temperature, Precipitation and all the parameterizations used for the simulations. Our purpose for generating and analyzing these simulations was to assess the role that root dynamics and foraging for water has in the recovery timescale of ecosystems following climate perturbation. All data provided are in the "netcdf" format using standard CF-1 (Climate and Forecast) Convention. The data are all machine readable using various software platforms including Matlab, NCO, Panoply and R.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Gap-filled methane and carbon dioxide fluxes across two ecosystem states at the US-OWC AmeriFlux site (2015−2016, 2020−2022)

This dataset contains gap-filled measurements of methane flux (FCH4), net ecosystem CO2 exchange (NEE) partitioned into gross primary productivity (GPP) and ecosystem respiration (RE), as well as latent heat flux (LE) from a Great Lakes coastal freshwater wetland at the US-OWC AmeriFlux site. The dataset covers the peak growing seasons (June−September) of 2015−2016, dominated by Typha spp., and 2020−2022, characterized by floating-leaved species (lotus and water lily). These data were generated to investigate how rising water levels and vegetation shifts influence CH4 and CO2 fluxes across two distinct ecosystem states in this wetland. The dataset, provided in CSV format, includes half-hourly gap-filled flux data from June to September for 2015, 2016, 2020, 2021, and 2022. The gap-filled data refers to measurements where missing values due to instrument issues or quality control were filled using artificial neural networks (ANNs).

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

AmeriFlux US-Jo2 Jornada Experimental Range Mixed Shrubland

This is the AmeriFlux version of the carbon flux data for the site US-Jo2 Jornada Experimental Range Mixed Shrubland. Site Description - The study area is in a mixed shrub-dominated portion of the San Andres Mountain piedmont, along the southeastern boundary of the Jornada Experimental Range (JER) in southern New Mexico, USA. The JER was established in 1912 as a response of scientis and landowner to the shrub enchroachment and loss of grasses due to extended grazing during the late 1800s, fire and climate change. JER has been a NSF LTER site since 1981.The study site is a small watershed (4.67 ha) in an alluvial slope or bajada, with three major areas (north-, south- and west-facing hillslopes) with low to moderate slopes (∼0–6°) with a mean slope of 2.6°, while the channel banks and propagating channel heads have higher slopes (∼15–25°). The site is charactetized by a high bare soil coverage (∼66%), ∼28% of mixed shrubs coverage and a low coverage of grass (∼4%) and weeds (∼2%).

Vivoni, Enrique R.↗
DOE OSTI2020

AmeriFlux CA-MA1 Manitoba Agricultural Site 1

This is the AmeriFlux version of the carbon flux data for the site CA-MA1 Manitoba Agricultural Site 1. Site Description - This field had been in perennial forages (grass with small amount of legume) for several decades. Field size = 39 ha. In 2008, the producer tilled the land so that part of the summer had perennial forage, and the remainder was fallow. In 2009, oats were planted. In 2010, canola was planted. In 2011, oats were planted. See Table 3 in Taylor et al (2013) describing site management practices.

Amiro, Brian↗
DOE OSTI2020

AmeriFlux CA-MA2 Manitoba Agricultural Site 2

This is the AmeriFlux version of the carbon flux data for the site CA-MA2 Manitoba Agricultural Site 2. Site Description - This field had been in perennial forages (grass with small amount of legume) for several decades. Field size = 60 ha. In 2009, the producer tilled the land so that part of the summer had perennial forage, and the remainder was fallow (see effect outlined by Fraser and Amiro 2013). In 2010, oats were planted. In 2011, the field was too wet to plant and remained fallow. Cattle were in the field for a brief period in June 2011to feed on weeds. See Table 2 in Taylor et al (2013) describing site management practices.

Amiro, Brian↗
DOE OSTI2020

AmeriFlux CA-MA3 Manitoba Agricultural Site 3

This is the AmeriFlux version of the carbon flux data for the site CA-MA3 Manitoba Agricultural Site 3. Site Description - This field has been in perennial forages (grass (timothy, fescue, brome) with small amount of legume) for several decades. Field size = 40 ha. Hay was harvested once each year. Cattle were placed in the field each autumn to graze. See Table 1 in Taylor et al (2013) describing site management practices.

Amiro, Brian↗
DOE OSTI2020

AmeriFlux US-ASM USSL San Joaquin Valley Almond Medium Salinity

This is the AmeriFlux version of the carbon flux data for the site US-ASM USSL San Joaquin Valley Almond Medium Salinity. Site Description - almond orchard in San Joaquin Valley. Different water source and water quality than adjacent site US-SAH

Anderson, Ray G.↗
DOE OSTI2020

AmeriFlux CA-CF2 Churchill Fen Site 2

This is the AmeriFlux version of the carbon flux data for the site CA-CF2 Churchill Fen Site 2. Site Description - Fen site dominated by sedges. Flat, high water table. Frozen for long periods each year. Close to Arctic Ocean coast so affected by land/sea breezes and coastal weather.

Tenuta, Mario↗
DOE OSTI2020

AmeriFlux US-HBK Hubbard Brook Experimental Forest

This is the AmeriFlux version of the carbon flux data for the site US-HBK Hubbard Brook Experimental Forest. Site Description - Mixed forest dominated by BEAL, ACRU with lesser components of PIRU. Gently sloped plateau within mountainous terrain.

Kelsey, Eric↗
DOE OSTI2020

AmeriFlux US-KM4 KBS Marshall Farms Smooth Brome Grass (Ref)

This is the AmeriFlux version of the carbon flux data for the site US-KM4 KBS Marshall Farms Smooth Brome Grass (Ref). Site Description - The site was recruited to the USDA’s Conservation Reserve Program (CRP) grassland in 1987 when it was planted to smooth brome grass. The grass was cut every three years but left in place until 2009; uncut since then.

Robertson, G. Philip↗
DOE OSTI2020

AmeriFlux US-NGC NGEE Arctic Council

This is the AmeriFlux version of the carbon flux data for the site US-NGC NGEE Arctic Council. Site Description - Subarctic tussock tundra, discontinuous permafrost

Torn, Margaret↗