A watershed in the coastal Canadian Arctic was sampled for dissolved carbon dioxide and methane concentration and stable carbon (carbon-13) isotopes to trace the transport, production, and consumption of carbon dioxide and methane during the spring thaw across a lake to bay transect. Two field campaigns were conducted in June 2022 and June-July 2023 out of the Canadian High Arctic Research Station (CHARS) in Cambridge Bay, Nunavut, Canada. Gas samples were collected via headspace extraction and transported back to the U.S. Geological Survey (USGS) Woods Hole Coastal and Marine Science Center (WHCMSC), where they were analyzed utilizing the USGS Automated Sample Introduction Module (AutoSIM) interfaced to a Picarro G2201-i CRDS (Cavity Ring-Down Spectrometer) to measure concentrations and stable carbon isotope ratios of methane and carbon dioxide. Field sampling was carried out by researchers from the Woods Hole Oceanographic Institution.

The Global Greenhouse Gas Reference Network for the Carbon Cycle and Greenhouse Gases (CCGG) Group is part of NOAA'S Earth System Research Laboratory (ESRL) in Boulder, CO. The Reference Network measures the atmospheric distribution and trends of the three main long-term drivers of climate change, carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), as well as carbon monoxide (CO) which is an important indicator of air pollution. The Reference Network measurement program includes continuous in-situ measurements at 4 baseline observatories (global background sites) and 8 tall towers, as well as flask-air samples collected by volunteers at over 50 additional regional background sites and from small aircraft. The air samples are returned to ESRL for analysis where measurements of about 55 trace gases are done. NOAA's Global Greenhouse Gas Reference Network maintains the World Meteorological Organization international calibration scales for CO2, CH4, CO, N2O, and SF6 in air. The measurements of the Global Greenhouse Gas Reference Network serve as a comparison with measurements made by many other international laboratories, and with regional studies. They are widely used in studies inferring space-time patterns of emissions and removals of greenhouse gases that are optimally consistent with the atmospheric observations. They serve as an early warning for climate "surprises". The measurements are also helpful for the ongoing evaluation of remote sensing technologies. Observatory Measurements: NOAA/ESRL/GMD operates four staffed atmospheric baseline observatories from which numerous measurements of greenhouse gases are conducted. These baseline observatories, also known as global background sites, are located in Barrow, Alaska; Mauna Loa, Hawaii; American Samoa; and South Pole, Antarctica. The measured data are baseline levels, trends, and causes of variability of atmospheric gases that have the potential to affect global climate. These observatories were established in order to provide a sampling of the most remote air on the planet so that the true "background atmosphere" could be monitored. GMD first began continuous in-situ measurements of CO2 at these observatories in 1973, and added CH4 and CO measurements in the 1980's. The ongoing data set is contingent upon the baseline observatories that are still in use going forward. A subset of Observatory Measurements for only carbon dioxide (CO2) taken from Observatories is archived separately with digital object identifiers (DOIs) for each of the four observation stations listed above. The observations run from 1973 through the end of 2016. The main portion of this agreement is for the enhanced "version" of the more encompassing dataset for all of the different types of observation platforms and gases. Through the Big Earth Data Initiative (BEDI), ESRL/GMD has taken their data collection and converted files into NetCDF-4, a self-describing format.

Determining how much methane and carbon dioxide cross the sea-air interface is critical when assessing marine greenhouse gas fluxes. This assessment is particularly important on Arctic Ocean continental margins, where rapid climate change is thawing glacial ice and permafrost; reducing sea ice cover; and changing water temperatures, salinities, nutrient loads, and ocean currents. This dataset was collected in the Sherard Osborn Fjord and adjacent areas of the Nares Strait and Lincoln Sea on the northern Greenland margin during the 2019 Ryder Expedition (known as SWEDARCTIC Ryder 2019), which is also identified as U.S. Geological Survey (USGS) Coastal and Marine Hazards and Resources Program Field Activity 2019-042-FA. The University of Stockholm led the expedition aboard the Swedish icebreaker Oden (IB Oden), in collaboration with the University of New Hampshire and the USGS. The dataset contains 30-second interpolated methane and carbon dioxide concentrations in near-surface seawater and the atmospheric marine boundary layer and provides the calculations used to determine the sea-air flux. The dataset also contains environmental data, including seawater salinity, wind speed, water and air temperatures, water depth, seawater pH, seawater dissolved oxygen, seawater fluorescent dissolved organic matter, seawater oxidation-reduction potential, seawater phycoerythrin, and seawater chlorophyll.

Determining how much methane and carbon dioxide cross the sea-air interface is critical when assessing marine greenhouse gas fluxes. This assessment is particularly important on Arctic Ocean continental margins, where rapid climate change is thawing glacial ice and permafrost; reducing sea ice cover; and changing water temperatures, salinities, nutrient loads, and ocean currents. This dataset was collected in the Sherard Osborn Fjord and adjacent areas of the Nares Strait and Lincoln Sea on the northern Greenland margin during the 2019 Ryder Expedition (known as SWEDARCTIC Ryder 2019), which is also identified as U.S. Geological Survey (USGS) Coastal and Marine Hazards and Resources Program Field Activity 2019-042-FA. The University of Stockholm led the expedition aboard the Swedish icebreaker Oden (IB Oden), in collaboration with the University of New Hampshire and the USGS. The dataset contains 30-second interpolated methane and carbon dioxide concentrations in near-surface seawater and the atmospheric marine boundary layer and provides the calculations used to determine the sea-air flux. The dataset also contains environmental data, including seawater salinity, wind speed, water and air temperatures, water depth, seawater pH, seawater dissolved oxygen, seawater fluorescent dissolved organic matter, seawater oxidation-reduction potential, seawater phycoerythrin, and seawater chlorophyll.

This dataset provides dissolved carbon dioxide (CO2) and methane (CH4) concentrations alongside their stable and radiocarbon isotopic compositions within the Arctic Sagavanirktok and Kuparuk River watersheds located on the North Slope of Alaska. The data were collected during the spring, fall, and summer seasons in 2022. In field separation of the bulk gaseous components (N2, CO2, and CH4) from the liquid phase was achieved using a degassing membrane contactor. Laboratory isotopic analyses were conducted at the W. M. Keck Carbon Cycle Accelerator Mass Spectrometer facility at UC Irvine. This collection aims to provide insights into the seasonal dynamics of greenhouse gas emissions in these critical Arctic environments, thereby contributing valuable information for climate change research and monitoring programs. The data are provided in comma separated values (CSV) format.

This dataset provides estimates of carbon dioxide (CO2) and methane (CH4) diffusive fluxes from waterbodies, and watershed landcover data for the central-interior of the Yukon-Kuskokwim Delta (YK delta), Alaska. Dissolved concentrations of methane and carbon dioxide were predicted using an integrated terrestrial-aquatic approach to scale observations based on landscape and waterbody remote sensing drivers. The observations include ~300 samples of surface water dissolved gases collected in July 2016-2019 from the central region of the YK Delta, Alaska. A machine learning model was used to generate estimated fluxes. Model inputs include Sentinel-2 MSI with derived normalized difference vegetation index (NDVI) and normalized difference water index (NDWI), an Arctic digital elevation model (DEM) with derived slope and flow accumulation, Sentinel-1 C-band July and December VV and VH composites, and a landcover map. Waterbody size, shape, and reflectance were determined using object-based image analysis in Google Earth Engine. Landscape-level input data were averaged in non-nested sub-basins calculated using the System for Automated Geoscientific Analyses (SAGA) "channel network" algorithm at three threshold sizes. Cross validation was used to tune and select variables for gradient boosting models. The trained gradient boosting models were then used to predict dissolved methane and carbon dioxide in all waterbodies (~17,000) in the region. These aquatic concentrations were converted to fluxes using an average gas transfer velocity from observations (0.33 m/d). The data are provided in GeoTIFF and shapefile formats.

Models project the Arctic Ocean will become undersaturated with respect to carbonate minerals in the next decade. Recent field results indicate parts may already be undersaturated in late summer months when ice melt is at its greatest extent; however, few comprehensive datasets of carbonate system parameters in the Arctic Ocean exist. Researchers from the U.S. Geological Survey (USGS) and University of South Florida (USF) collected high-resolution measurements of pCO2, pH, total dissolved inorganic carbon (DIC), total alkalinity (TA), and carbonate (CO3-2) from the Canada Basin to fill critical information gaps concerning Arctic carbon variability. A Multiparameter Inorganic Carbon Analyzer (MICA) was used to collect approximately 1,800 measurements of pH and DIC along an 11,965-km trackline in August and September 2012. In addition, over 500 discrete surface water samples were taken. These data are being used to characterize and model regional pCO2, pH, and carbonate mineral saturation state. A high-resolution, three-dimensional map of these results will be presented.

Models project the Arctic Ocean will become undersaturated with respect to carbonate minerals in the next decade. Recent field results indicate parts may already be undersaturated in late summer months when ice melt is at its greatest extent; however, few comprehensive datasets of carbonate system parameters in the Arctic Ocean exist. Researchers from the U.S. Geological Survey (USGS) and University of South Florida (USF) collected high-resolution measurements of pCO2, pH, total dissolved inorganic carbon (DIC), total alkalinity (TA), and carbonate (CO3-2) from the Canada Basin to fill critical information gaps concerning Arctic carbon variability. A Multiparameter Inorganic Carbon Analyzer (MICA) was used to collect approximately 1,800 measurements of pH and DIC along an 11,965-km trackline in August and September 2012. In addition, over 500 discrete surface water samples were taken. These data are being used to characterize and model regional pCO2, pH, and carbonate mineral saturation state. A high-resolution, three-dimensional map of these results will be presented.

This dataset includes discrete sample and profile data collected during United Nations Convention on the Law of the Sea (UNCLOS) cruises 2014-10, 2015-05, and 2016-15 by Natural Resources of Canada (NRCan) in the Arctic Ocean, Beaufort Sea and Canada Basin from 2014-08-28 to 2016-09-13. These data include dissolved inorganic carbon (DIC), total alkalinity (TA), pH, pCO2, methane, nutrients, dissolved oxygen, water temperature, salinity and other measurements. The United Nations Convention on the Law of the Sea (UNCLOS) cruise was conducted by Natural Resources of Canada (NRCan). Samples for Dissolved Inorganic Carbon and Total Alkalinity were collected on board of Louis St. Larent in the Beaufort Sea and the Canada Basin.