cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.18739/a2k649v0z
title: Soil and heterotrophic respiration, understory photosynthesis, soil temperature and moisture, for Alaskan boreal forests with different burn frequencies

description: Fire frequency is increasing with climate warming in the boreal regions of interior Alaska, with short fire return intervals ( less than 50 years) becoming more common. Recent studies suggest these ‘‘reburns’’ will reduce the insulating surface organic layer and seedbanks, inhibiting black spruce regeneration and increasing deciduous cover. These changes are projected to amplify soil warming, increasing mineral soil organic carbon (SOC) decomposition rates, and impair re-establishment of understorey vegetation and the SOL (soil organic layer). We examined how reburns changed soil temperature, heterotrophic soil respiration (RH), and understorey gross primary production (GPP) and related these fluxes to soil environmental variables (temperature and moisture) and photosynthetically active radiation (PAR) and air temperature. Two distinct burn complexes previously covered by spruce were measured; both included areas burned 1x, 2x, and 3x over 60 years and mature (~90 year old) spruce forests underlain by permafrost.
DOI: 10.18739/a2kh0f10f
title: Firn density and ice content at sites along the west Expéditions Glaciologiques Internationales au Groenland (EGIG) line, Greenland, 2022

description: The thermal and structural transformation that Greenland's firn layer is presently undergoing has important implications for the ice sheet's capacity to retain future melt. This project is directly observing firn evolution with a network of instruments installed within the firn layer and with ice cores sampling the firn. This archive contains data collected at sites located along the lower elevation portion of the Expéditions Glaciologiques Internationales au Groenland (EGIG) line, western Greenland Ice Sheet. The data include the physical stratigraphy measured in firn cores extending to depths of up to ~30 m with measurements of firn density and refrozen ice content. The data were collected as part of an Arctic Observing Network (AON) project funded by the U.S. National Science Foundation. Each of the study sites is located in the Greenland Ice Sheet’s Percolation Zone, the outer flanks of the accumulation zone that experiences surface melt during the summer period. Data collection for this AON project began in 2022, and is expected to continue through 2025. This dataset will be associated with additional datasets, including physical stratigraphy and density measured in ice cores and firn temperature time series measured in core holes, as they become available in future years. Additional sites with will be added in future years, and additional data from existing sites will be collected.
DOI: 10.18739/a2kw57k4r
title: Calibrated mass loss projections from the Greenland Ice Sheet

description: Data files are available at: https://arcticdata.io/data/10.18739/A2KW57K4R/ The potential contribution of ice sheets remains the largest source of uncertainty in projecting sea-level due to the limited predictive skill of numerical ice sheet models, yet effective planning for coming sea level rise necessitates that predictions are credible and accompanied by a defensible assessment of uncertainty. Characterization of the likelihood of upper-end contributions are particularly important for developing adaptation strategies. While the use of large ensembles of simulations allows these kinds probabilistic assessments, there is no guarantee that simulations are aligned with observations. Here, we show that calibrating an ensemble of model simulations on observations reduces uncertainties in projecting 21st century mass loss from the Greenland Ice Sheet relative to a plausible a priori distribution of model configurations. We find that jointly conditioning on surface speeds and cumulative mass loss reduces the projected 2100 median contribution and 5-95th percentile by 16-30% and 38-56, respectively, compared to the un-calibrated ensemble, resulting in calibrated sea-level contributions ranging from 4 to 30 centimeters at the year 2100. This data set contains several products: - Surrogate model training data. ~1000 surface speed realizations in netCDF format, prepared with the Parallel Ice Sheet Model (PISM, www.pism.io) - Trained emulators. 50 trained emulators in HDF5 format, prepared with PyTorch (www.pytorch.org) - Posterior parameter distributions. 50 posterior distributions in CSV format. - Scalar time series of projected ice sheet-wide mass change. Time series of projected mass change from 2008 until 2100 in CSV format, prepared with the Parallel Ice Sheet Model (PISM, www.pism.io), for both the ensemble using the Prior and the Posterior (calibrated) parameter distribution. ~500 realizations for each Representative Concentration Pathway (RCP) scenario 2.6, 4.5, and 8.5. - Spatial time series of projected ice sheet change from 2008 until 2300 in netCDF format. The following variables are included: mass, surface elevation, surface speeds, and ice mask. Simulations were prepared with the Parallel Ice Sheet Model (PISM, www.pism.io) for the Posterior (calibrated) parameter distribution. ~500 realizations for each Representative Concentration Pathway (RCP) scenario 2.6, 4.5, and 8.5. The code to produce the emulators, generate the posterior distributions, and perform the importance sampling can be found at https://doi.org/10.5281/zenodo.6257002.
DOI: 10.18739/a2m03xz70
title: Water pressure measurements from Sarqardleq Fjord, West Greenland, over July 12-18, 2012

description: Sarqardleq Fjord is part of a tidewater glacier-fjord system in western Greenland. These observations of water pressure were collected as part of a field program to study the dynamics of the ice/ocean boundary layer of a medium-sized glacier. The glacier's margins are characterized by turbulent plumes fed by subglacial discharge, as well as broader, quiescent regions characterized by submarine melt. Ocean property and velocity data were collected to characterize the spatial and temporal variability of the near-ice dynamics. The water pressure observations are from a shallow mooring that was deployed from July 18, 2012 to July 18, 2012, and sampled at 1 second intervals. The mooring was primarily deployed to record the tidal cycle in the fjord.
DOI: 10.18739/a2m32nb78
title: Dissertation research. Indigenous Land Defence: Emerging Networks of Survival. Wet'suwet'en territory, Northern British Columbia, Canada. 2018-2022.

description: Auto-ethnographic research at land defence encampments on Wet'suwet'en land in Northern British Columbia, Canada. Research included media analysis, historical research, and participant observation from 2018-2022. Indigenous peoples are developing novel social mechanisms to deal with rapid change and emerging conflicts, including land resettlement, language revitalization and traditional skill-building. However, we know little about the processes and contexts from which these strategies arise. This project will use a case study from the Northwest Coast of North America to evaluate how Indigenous communities socially and culturally adapt to conflicts over sovereignty, land use and access. This research aims to document the new social networks that emerge in these contexts and how they contribute to Indigenous resiliency. To understand the opportunities and consequences of emerging networks, this project will (1) document the socio-cultural norms that emerge amidst Indigenous resettlement of traditional territories; (2) identify types of social networks that develop; (3) evaluate connections between these new networks and gender, race, and economic factors. The ultimate objective is to trace community networks and evaluate their impacts on Indigenous resilience, an issue with broad implications for Arctic Indigenous communities.
DOI: 10.18739/a2m61br25
title: Minute-averaged carbon dioxide dry air mole fractions measured in the University of Colorado container during the 2019-2020 MOSAiC (Multidisciplinary drifting Observatory for the Study of Arctic Climate) expedition

description: This dataset contains ambient air minute-averaged carbon dioxide dry air mole fractions measured in the Central Arctic during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. The backbone of MOSAiC was the year-round operation of the Research Vessel Polarstern that drifted with the sea ice across the Central Arctic from October 2019 to September 2020. Measurements were performed onboard Polarstern in the University of Colorado sea-laboratory container installed below deck in the forward cargo hold. A ~50 meter (m) long Teflon sampling line was deployed from the container to the bow crane to allow measurements forward of the vessel.
DOI: 10.18739/a2m90246c
title: Short interval fires increasing in Alaska boreal forest as fire self-regulation decays, 2018-2021.

description: Climate drivers are increasingly creating conditions conducive to higher frequency fires. In the coniferous boreal forest, the world’s largest terrestrial biome, fires are historically common but relatively infrequent. Post-fire, regenerating forests are generally resistant to burning (strong fire self-regulation), favoring millennial coniferous resilience. However, short intervals between fires are associated with rapid, threshold-like losses of resilience and changes to broadleaf or shrub communities, impacting carbon content, habitat, and other ecosystem services. Fires burning the same location 2 + times comprise approximately 4% of all Alaskan boreal fire events since 1984, and the fraction of short-interval events (less than 20 years between fires) is increasing with time. While there is strong resistance to burning for the first decade after a fire, from 10 to 20 years post-fire resistance appears to decline. Reburning is biased towards coniferous forests and in areas with seasonally variable precipitation, and that proportion appears to be increasing with time, suggesting continued forest shifts as changing climatic drivers overwhelm the resistance of early postfire landscapes to reburning. As area burned in large fire years of ~ 15 years ago begin to mature, there is potential for more widespread shifts, which should be evaluated closely to understand finer grained patterns within this regional trend.
DOI: 10.18739/a2mc8rh7s
title: A Comparison of Plant Use in Three Beringian Societies, Chukotka and Alaska, 2014-2022

description: This dataset compares the edible and medicinal plant uses of the Chukchi and Naukan Yupik of Chukotka and the Central Alaskan Yup'ik. The purpose is to examine whether there are more similarities in medical beliefs between two societies speaking similar languages and sharing a deep historical root (Naukan Yupik and Central Alaskan Yup'ik), or between two societies speaking unrelated languages, but sharing the more recent influence of the dominant Russian culture (Naukan and Chukchi). Although all three study cultures share many of the same ideas about the edibility of local plants species, the two Russian cultures (Naukan and Chukchi) are much more similar to each other than either are to Central Alaskan Yup'ik in terms of their medical ethnobotany. The greater similarity between Naukan and Chukchi cultures can be explained both by intercultural borrowing and by the fact that both groups have adopted many Russian medicinal plant uses.
DOI: 10.18739/a2mp4vp7v
title: Soil enzymes are preferentially associated with larger particles in highly organic Arctic tundra soils (enzyme activity)

description: In the soil cores, our results showed activity was present for most of the hydrolytic enzymes and there were clear differences among the particle size and disruption treatments. In the sonication + blending treatment, five of six hydrolytic enzymes showed higher activity compared to blending only (standard treatment) or sonication only, suggesting that enzymes are bound to larger particles of the soil as opposed to smaller such as clays and tannins. Furthermore, higher activities in unfiltered and 50 µm (micrometer) filters relative to much finer 2 µm filters suggested that the enzymes were preferentially bound to larger particles in the soil, meaning that enzymes are not equally distributed across the soil matrix. These results suggest that the enzymes are likely bound to the larger organic substrates they are decomposing, potentially preventing their transport away from the microbes that produce them.
DOI: 10.18739/a2n00zv6r
title: Wintertime (2020-2021) hydrographic measurements in the Northern Bering and Chukchi Seas from USCGC (United States Coast Guard Cutter) Polar Star

description: During Arctic West Winter 2021 (AWW21), USCGC (United States Coast Guard Cutter) Polar Star launched expendable conductivity- temperature-depth (XCTD) probes in support of a science mission to investigate the formation of winter water in the Northern Bering and Chukchi Seas. This cold water is critical to the functioning of the regional ecosystem since it contains high levels of nutrients that spur primary production in the spring. However, due to the dearth of wintertime data, very little is known about how/where the water is formed and how it evolves through the winter. The data collected by Polar Star offered a rare opportunity to investigate these issues. During the first phase of AWW21, 28 XCTD probes were successfully dropped from just south of Bering Strait to the latitude of Hanna Shoal in the Chukchi Sea, mainly in the vicinity of the US (United States)/Russian convention line. This was done over the time period 18 December 2020 – 1 January 2021. During the second phase, 42 probes were successfully launched, predominantly over the northern Bering shelf, from 11 January – 2 February 2021. Most of the drops were done in significant, but varied, ice cover. This included numerous drops within re-freezing leads during which time winter water is readily modified. Near the end of the cruise, a sequence of probes was launched as the ship steamed through the marginal ice zone into open water (near 59°N (North)). The overall data return was excellent; there were only 7 failed probes despite the harsh conditions, and the quality of the data was high. This is a testament to the hard work and dedication of NOAA (National Oceanic and Atmospheric Administration) LT (Lieutenant) Lydia Ames and her fellow XCTD team members: LT Lauren Kowalski, DV2 (Diver Second Class) Charles Fox, MK2 (Machinery Technician Petty Officer Second Class) Tedd Meinersmann, and NIC (National Ice Center) sea-ice analyst Evan Neuwirth. We are indebted to Captain William Woityra and the crew of Polar Star for collecting this rare wintertime data set under such challenging conditions, and to the Coast Guard Pacific Area staff for their critical role in formulating the mission and for facilitating the science, including CDR (Commander) Robert Kinsey, CAPT (Captain) Rodrigo Rojas, LCDR (Lieutenant Commander) Andrew Dennelly, and Science Liaison Phillip McGillivary. Finally, we gratefully acknowledge the National Science Foundation Office of Polar Programs who funded the XCTD measurements with RAPID (Rapid Response Research) grant OPP (Office of Polar Programs) -2110148.
DOI: 10.18739/a2n873162
title: Sulfur isotopes of sulfate measurements from a Greenland ice core (1200-1850) and volcanic gas measurements from various volcanoes and hot springs in Iceland

description: The Arctic is warming at almost four times the global rate. Cooling caused by anthropogenic aerosols has been estimated to offset sixty percent of greenhouse-gas-induced Arctic warming, but the contribution of aerosols to radiative forcing (RF) represents the largest uncertainty in estimating total RF, largely due to unknown preindustrial aerosol abundance. Here, sulfur isotope measurements in a Greenland ice core show that passive volcanic degassing contributes up to 66 ± 10% of preindustrial ice core sulfate in years without major eruptions. A state-of-the-art model indicates passive volcanic sulfur emissions influencing the Arctic are underestimated by up to a factor of three, possibly because many volcanic inventories do not include hydrogen sulfide emissions. Higher preindustrial volcanic sulfur emissions reduce modeled anthropogenic Arctic aerosol cooling by up to a factor of two (+0.11 to +0.29 W m-2 (watts per square meter)), suggesting that underestimating passive volcanic sulfur emissions has significant implications for anthropogenic-induced Arctic climate change. These data include sulfur isotopes of sulfate measurements from a Greenland ice core and volcanic gas measurements (CO2:S (carbon dioxide:sulfur) ratios) from various volcanoes and hot springs in Iceland.
DOI: 10.18739/a2nk3665n
title: Pan-Arctic surface water (yearly and trend over time) 2000-2022

description: Surface water change has been documented across the Arctic due to thawing permafrost and changes in the precipitation/evapotranspiration balance. This dataset uses Moderate Resolution Imaging Spectroradiometer (MODIS) data to track changes in surface water across the region over the past two decades. The superfine water index (SWI) is a unitless global water cover index developed specifically for MODIS data and validated in high northern latitudes. Variation in SWI can also track changes in surface water that occur at the sub-MODIS pixel scale (i.e., changes in water bodies smaller a MODIS pixel, ~500 meters (m)). This dataset (1) maps the average July SWI over pan-Arctic for each year of the MODIS record (2000-2021) and (2) maps the trends in July SWI over 2000-2012 (i.e., Sen's slope of the pixel-wise SWI vs. time). The spatial resolution of this dataset is ~500 m. The yearly SWI files are processed for the entire continuous and discontinuous permafrost zone. The 2000-2021 trend file is processed for lake-rich regions of the Arctic (i.e., lake coverage greater than 5%), as was published in the Webb et al, 2022 paper. The 2000-2022 trend file is processed for the entire continuous and discontinuous permafrost zone. Corresponding publication: Webb, Elizabeth E., Anna K. Liljedahl, Jada A. Cordeiro, Michael M. Loranty, Chandi Witharana, and Jeremy W. Lichstein (2022), Permafrost thaw drives surface water decline across lake-rich regions of the Arctic, Nature Climate Change, doi.org/10.1038/s41558-022-01455-w
DOI: 10.18739/a2ns0m01x
title: Shelf-Break Upwelling in the Western Beaufort Sea – Acoustic Doppler Current Profiler (ADCP) Velocity and Backscatter Amplitude collected using the R/V Sikuliaq 150 kHz ADCP, 2017

description: This data set contains processed acoustic Doppler current profiler (ADCP) data collected from the research vessel (R/V) Sikuliaq during August 25-September 18, 2017 on a cruise to the Western Beaufort Shelf. The data were collected to document water velocities and backscatter during a project focusing on the bio-physical impacts of upwelling along the Beaufort Shelf. Data were collected using the hull-mounted 150 kHz ADCP continuously from the start/end port of Nome, AK, through Bering Strait and the Chukchi Sea to the working area along the shelf-break approximately north of Nuiqsut Ak. Data were processed at the Woods Hole Oceanographic Institution using the University of Hawaii Common Ocean Data Access System (CODAS) ADCP data processing system by Frank Bahr. The data set contains year, decimal date (yearday.time, Jan 1= Day 0, decimal time in GMT), position (latitude, longitude), and water depth for profiles of velocity (undetided and detided, m/s), percent good, and backscatter amplitude. Data are provided both as an excel file and as text (tab delimited) file.
DOI: 10.18739/a2nv99c36
title: Benthic macroinfaunal samples collected from the Canadian Coast Guard Ship (CCGS) Sir Wilfrid Laurier, Northern Bering Sea to Chukchi Sea, 2016

description: The Pacific sector of the Arctic Ocean is experiencing major reductions in seasonal sea ice extent and increases in sea surface temperatures. One of the key uncertainties in this region is how the marine ecosystem will respond to seasonal shifts in the timing of spring sea ice retreat and/or delays in fall sea ice formation. Variations in upper ocean water hydrography, planktonic production, pelagic-benthic coupling and sediment carbon cycling are all influenced by sea ice and temperature change. To more systematically track the broad biological response to sea ice retreat and associated environmental change, an international consortium of scientists have developed a coordinated “Distributed Biological Observatory” (DBO) that includes selected biological measurements at multiple trophic levels, along with satellite and mooring measurements. The DBO currently focuses on five regional biological “hotspot” locations along a latitudinal gradient that allows for consistent sampling and monitoring at five biologically productive locations across a latitudinal gradient: DBO 1 (SLIP)-south of St. Lawrence Island (SLI), DBO2 (Chirikov)-north of SLI, DBO3 (southern Chukchi Sea), DBO4-NE Chukchi Sea,and DBO5-Barrow Canyon. This dataset contains benthic macroinfaunal population level from sediment samples collected at each station for the United States Coast Guard Cutter (USCGC) Healy cruise-Leg 1 in 2017, identified by station number (#), Station name (Stn. Name), Date (mm/dd/yy), latitude (°N), longitude (°W), and station depth (m). The following macroinfaunal parameters were determined: abundance, wet weight biomass (grams of wet weight per meters squared), dry weight biomass (grams of Carbon per meters squared), and taxon type.
DOI: 10.18739/a2nz80r4j
title: North Pacific and Arctic Marine Vessel Traffic Dataset (2015-2020); 10 Kilometer Resolution.

description: These data are a spatially explicit representation of monthly shipping intensity in the Pacific Arctic region from January 1, 2015 to December 31, 2020. We calculated shipping intensity based on Automatic Identification System (AIS) data, a type of Global Positioning System (GPS) transmitter required by the International Maritime Organization on all ships over 300 gross tonnes on an international voyage, all cargo ships over 500 gross tonnes, and all passenger ships. We used AIS data received by the exactEarth satellite constellation (64 satellites as of 2020), ensuring spatial coverage regardless of national jurisdiction or remoteness. Our analytical approach converted raw AIS input into monthly raster datasets, separated by vessel type. We first filtered raw AIS messages to remove spurious records and GPS errors, then joined remaining vessel positional records with static messages including descriptive attributes. We further categorized these messages into one of four general ship types (cargo; tanker; fishing; and other). To develop the raster dataset, we created a series of spatially explicit daily vessel tracks according to unique voyages and aggregated tracks by ship type and month. We then created a 10-km raster grid and calculated the total length, in meters, of all vessel tracks within each raster cell. These monthly datasets provide a critical snapshot of dynamic commercial and natural systems in the Pacific Arctic region. Recent declines in sea ice have lengthened the duration of the shipping season and have expanded the spatial coverage of large vessel routes, from the Aleutian Islands through the Bering Strait and into the southern Chukchi Sea. As vessel traffic has increased, so has exposure to the myriad environmental risks posed by large ships, including oil spills, underwater noise pollution, large cetacean ship-strikes, and discharges of pollutants. This dataset provides scientific researchers, local community members, mariners, and decision-makers with a quantitative means to evaluate the distribution and intensity of shipping across space and through time. In addition to these 10-km raster data, we also produced data products in 25-km raster format as well as a 1-km coastal data subset and a hex data set which contains additional attributes (e.g., number of ships, ship speed). To find these products, search for “North Pacific and Arctic Marine Vessel Traffic Dataset” in the Arctic Data Center’s data repository.