11 research outputs found
Vegetation type is an important predictor of the arctic summer land surface energy budget
Despite the importance of high-latitude surface energy budgets (SEBs) for land-climate interactions in the rapidly changing Arctic, uncertainties in their prediction persist. Here, we harmonize SEB observations across a network of vegetated and glaciated sites at circumpolar scale (1994-2021). Our variance-partitioning analysis identifies vegetation type as an important predictor for SEB-components during Arctic summer (June-August), compared to other SEB-drivers including climate, latitude and permafrost characteristics. Differences among vegetation types can be of similar magnitude as between vegetation and glacier surfaces and are especially high for summer sensible and latent heat fluxes. The timing of SEB-flux summer-regimes (when daily mean values exceed 0 Wm(-2)) relative to snow-free and -onset dates varies substantially depending on vegetation type, implying vegetation controls on snow-cover and SEB-flux seasonality. Our results indicate complex shifts in surface energy fluxes with land-cover transitions and a lengthening summer season, and highlight the potential for improving future Earth system models via a refined representation of Arctic vegetation types.An international team of researchers finds high potential for improving climate projections by a more comprehensive treatment of largely ignored Arctic vegetation types, underscoring the importance of Arctic energy exchange measuring stations.Peer reviewe
Vegetation type is an important predictor of the arctic summer land surface energy budget
Despite the importance of high-latitude surface energy budgets (SEBs) for land-climate interactions in the rapidly changing Arctic, uncertainties in their prediction persist. Here, we harmonize SEB observations across a network of vegetated and glaciated sites at circumpolar scale (1994â2021). Our variance-partitioning analysis identifies vegetation type as an important predictor for SEB-components during Arctic summer (June-August), compared to other SEB-drivers including climate, latitude and permafrost characteristics. Differences among vegetation types can be of similar magnitude as between vegetation and glacier surfaces and are especially high for summer sensible and latent heat fluxes. The timing of SEB-flux summer-regimes (when daily mean values exceed 0 Wmâ2) relative to snow-free and -onset dates varies substantially depending on vegetation type, implying vegetation controls on snow-cover and SEB-flux seasonality. Our results indicate complex shifts in surface energy fluxes with land-cover transitions and a lengthening summer season, and highlight the potential for improving future Earth system models via a refined representation of Arctic vegetation types
Biological-Templating of a Segregating Binary Alloy for Nanowire-Like Phase-Change Materials and Memory
One of the best strategies for achieving faster computers is to mitigate the millisecond-order time delays arising from the transfer and storage of information between silicon- A nd magnetic-based memories. Segregating-binary-alloy (SBA)-type phase-change materials (PCMs), such as gallium antimonide-based systems, can store information on 10 ns time scales by using a single memory structure; however, these materials are hindered by the high consumption of energies and undergo elemental segregation around 620 K. Nanowire-like PCMs can achieve low-energy consumption but are often synthesized by vapor-liquid-solid methods above 720 K, which would cause irreversible corruption of SBA-based PCMs. Here we control the morphology, composition, and functionality of SBA-type germanium-tin oxide systems using template-driven nucleation that leverages the electrostatic-binding specificity of the M13 bacteriophage surface. A wirelike PCM was achieved, with controllable and reliable phase-changing signatures, capable of tens of nanoseconds switching times. This approach addresses some of the critical material compositional and structural constraints that currently diminish the utility of PCMs in universal memory systems
Highly Adjustable 3D Nano-Architectures and Chemistries via Assembled 1D Biological Templates
Porous
metal nanofoams have made significant contributions to a diverse set of
technologies from separation and filtration to aerospace. Nonetheless, finer control over nano and
microscale features must be gained to reach the full potential of these
materials in energy storage, catalytic, and sensing applications. As biologics naturally occur and assemble
into nano and micro architectures, templating on assembled biological materials
enables nanoscale architectural control without the limited chemical scope or
specialized equipment inherent to alternative synthetic techniques. Here, we rationally assemble 1D biological
templates into scalable, 3D structures to fabricate metal nanofoams with a
variety of genetically programmable architectures and material
chemistries. We demonstrate that
nanofoam architecture can be modulated by manipulating viral assembly,
specifically by editing the viral surface coat protein, as well as altering
templating density. These architectures
were retained over a broad range of compositions including monometallic and
bi-metallic combinations of noble and transition metals of copper, nickel,
cobalt, and gold. Phosphorous and boron
incorporation was also explored. In addition to increasing the surface area
over a factor of 50, as compared to the nanofoamâs geometric footprint, this
process also resulted in a decreased average crystal size and altered phase
composition as compared to non-templated controls. Finally, templated hydrogels
were deposited on the centimeter scale into an array of substrates as well as
free standing foams, demonstrating the scalability and flexibility of this
synthetic method towards device integration.
As such, we anticipate that this method will provide a platform to
better study the synergistic and de-coupled effects between nano-structure and
composition for a variety of applications including energy storage, catalysis,
and sensing
Vegetation type is an important predictor of the arctic summer land surface energy budget
Despite the importance of high-latitude surface energy budgets (SEBs) for land-climate interactions in the rapidly changing Arctic, uncertainties in their prediction persist. Here, we harmonize SEB observations across a network of vegetated and glaciated sites at circumpolar scale (1994â2021). Our variance-partitioning analysis identifies vegetation type as an important predictor for SEB-components during Arctic summer (June-August), compared to other SEB-drivers including climate, latitude and permafrost characteristics. Differences among vegetation types can be of similar magnitude as between vegetation and glacier surfaces and are especially high for summer sensible and latent heat fluxes. The timing of SEB-flux summer-regimes (when daily mean values exceed 0 Wmâ2) relative to snow-free and -onset dates varies substantially depending on vegetation type, implying vegetation controls on snow-cover and SEB-flux seasonality. Our results indicate complex shifts in surface energy fluxes with land-cover transitions and a lengthening summer season, and highlight the potential for improving future Earth system models via a refined representation of Arctic vegetation types.ISSN:2041-172
Literature synthesis data of surface energy fluxes and environmental drivers from Arctic vegetation and glacier sites
Despite the importance of surface energy budgets (SEBs) for land-climate interactions in the Arctic, uncertainties in their prediction persist. In situ observational data of SEB components - useful for research and model validation - are collected at relatively few sites across the terrestrial Arctic, and not all available datasets are readily interoperable. Furthermore, the terrestrial Arctic consists of a diversity of vegetation types, which are generally not well represented in land surface schemes of current Earth system models.
This dataset describes the data generated in a literature synthesis, covering 358 study sites on vegetation or glacier (>=60°N latitude), which contained surface energy budget observations. The literature synthesis comprised 148 publications searched on the ISI Web of Science Core Collection
Harmonized in-situ observations of surface energy fluxes and environmental drivers at 64 Arctic vegetation and glacier sites - Metadata
Despite the importance of surface energy budgets (SEBs) for land-climate interactions in the Arctic, uncertainties in their prediction persist. In situ observational data of SEB components - useful for research and model validation - are collected at relatively few sites across the terrestrial Arctic, and not all available datasets are readily interoperable. Furthermore, the terrestrial Arctic consists of a diversity of vegetation types, which are generally not well represented in land surface schemes of current Earth system models.
This dataset contains metadata information about surface energy budget components measured at 64 tundra and glacier sites >60° N across the Arctic. This information was taken from the open-access repositories FLUXNET, Ameriflux, AON, GC-Net and PROMICE. The contained datasets are associated with the publication vegetation type as an important predictor of the Arctic Summer Land Surface Energy Budget by Oehri et al. 2022, and intended to support research of surface energy budgets and their relationship with environmental conditions, in particular vegetation characteristics across the terrestrial Arctic
Harmonized in-situ observations of surface energy fluxes and environmental drivers at 64 Arctic vegetation and glacier sites
Despite the importance of surface energy budgets (SEBs) for land-climate interactions in the Arctic, uncertainties in their prediction persist. In-situ observational data of SEB components - useful for research and model validation - are collected at relatively few sites across the terrestrial Arctic, and not all available datasets are readily interoperable. Furthermore, the terrestrial Arctic consists of a diversity of vegetation types, which are generally not well represented in land surface schemes of current Earth system models. Therefore, we here provide four datasets comprising:
1. Harmonized, standardized and aggregated in situ observations of SEB components at 64 vegetated and glaciated sites north of 60° latitude, in the time period 1994-2021
2. A description of all study sites and associated environmental conditions, including the vegetation types, which correspond to the classification of the Circumpolar Arctic Vegetation Map (CAVM, Raynolds et al. 2019).
3. Data generated in a literature synthesis from 358 study sites on vegetation or glacier (>=60°N latitude) covered by 148 publications.
4. Metadata, including data contributor information and measurement heights of variables associated with Oehri et al. 2022
Harmonized in-situ observations of surface energy fluxes and environmental drivers at 64 Arctic vegetation and glacier sites - Surface energy budget componenent data
Despite the importance of surface energy budgets (SEBs) for land-climate interactions in the Arctic, uncertainties in their prediction persist. In situ observational data of SEB components - useful for research and model validation - are collected at relatively few sites across the terrestrial Arctic, and not all available datasets are readily interoperable. Furthermore, the terrestrial Arctic consists of a diversity of vegetation types, which are generally not well represented in land surface schemes of current Earth system models.
This dataset comprises harmonized, standardized and aggregated in-situ observations of surface energy budget components measured at 64 sites on vegetated and glaciated sites north of 60° latitude, in the time period from 1994 till 2021. The surface energy budget components include net radiation, sensible heat flux, latent heat flux, ground heat flux, net shortwave radiation, net longwave radiation, surface temperature and albedo, which were aggregated to daily mean, minimum and maximum values from hourly and half-hourly measurements. Data were retrieved from the monitoring networks FLUXNET, AmeriFlux, AON, GC-Net and PROMICE