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Topographic Correction for Geothermal Heat Flow in Greenland and Antarctica
No full textTopographic correction for geothermal heat flux across both Greenland and Antarctica. This dimensionless correction field is derived from a statistical model applied to BedMachine bed topography. Applying this small-scale topographic correction to independent large-scale geothermal heat flux fields renders them more self-consistent with local bed topography
Hagen Bræ - data and model output from Winton et al., 2021
No full textThis dataset contains a description of the data presented in Winton et al., 2021.
For the data not previously published elsewhere, this dataset will contain a data file.
For the data already published elsewhere, this dataset will contain a description of how to obtain the data and the appropriate citation
Detection of slush on the Greenland Ice Sheet using Moderate Resolution Imaging Spectroradiometer (MODIS) satellite imagery
No full textSea Level Rise (SLR) is a growing global concern that is heavily influenced by a warming climate. Because of a potentially large added mass to the ocean through ice melt, the Greenland Ice Sheet (GrIS) plays an important role in the contribution to SLR. The presence of slush on Greenland is the result of melting processes and it can work as an indicator of surface mass balance (SMB) patterns on the ice sheet. This paper presents a detection of slush on the GrIS and the spatiotemporal evolution of slush during the study period 2000-2019. An upper limit of slush, known as the slush-line is also presented. A method is used which looks at spatial variability of albedo to detect slush on Moderate Resolution Imaging Spectroradiometer (MODIS) satellite imagery.
Classification of daily satellite imagery during the study period showed a presence of slush mainly during the melting season mid-May to September each year. During the study period, slush-extents and the elevation of the slush-line were fluctuating over the years. An exceptionally large presence of slush was detected during the summer of 2012. Greater areas of slush were found on the western areas of the ice sheet; particularly large areas of slush were detected in the southwest. Slush-extent and the elevation of the slush-line showed a generally positive correlation, where an increased slush-extent results in a higher slush-line elevation. This relationship was particularly strong in the western and southern areas, while a weaker relationship was found in the eastern and northern parts of the ice sheet. This pattern is potentially related to variations in complexity of the physical environment. General developments of slush-extents over the study period show an agreement with previous studies on mass balance and particularly agree with measured cumulative melt-day extents for each year
Greenland diamond exploration data package
No full textThe Government of Greenland’s Diamond exploration data package compiles over 50 years of diamond exploration data. In addition to samples derived from Greenland’s established areas of diamondiferous rocks in central West Greenland, a wide coverage of regional exploration data extending throughout the country is included.The Diamond exploration data package is the first of its kind to collate diamond exploration data country-wide in a publicly accessible fashion. It incorporates the locations of 25 000 diamond exploration samples. Associated with these samples are over 109,000 good-quality chemical analyses of mineral separate grains integrated into a standardised framework. In total, 100 discrete, named in-situ bodies, which in principle have diamond potential (kimberlites, lamproites, ultramafic lamprophyres, and carbonatites) have also been compiled in the diamond exploration data package. These occur among over 3000 compiled in situ occurrences of dykes, pipes, sills and blows.Size: 8.7 GB
The firn meltwater retention model intercomparison project (RetMIP): model outputs
No full textThis dataset comprises the outputs from nine firn models at four sites of the Greenland ice sheet produced for the firn meltwater Retention Intercomparison Project (RetMIP).
The nine models were forced by the same weather-station-derived mass and energy fluxes. The simulated firn density, temperature, liquid water content, refreezing rates and ice fraction are interpolated on the same grid from the surface down to 20 m deep with 10 cm vertical resolution. For each three-hourly time step, the total firn air and water content, total refreezing and total runoff simulated in the entire firn column are also calculated for each model. For one of the sites, Dye-2, two simulations are provided: one spanning over 17 years and one restricted to the 2016 melt season using a more recent weather station for the forcing.
The forcing data for these model runs are available here:
Vandecrux, Baptiste, 2020, "The firn meltwater retention model intercomparison project (RetMIP): forcing data", https://doi.org/10.22008/FK2/GZ3CSN, GEUS Dataverse, V
Streams, Outlets, and Basins [k=0.9]
No full textGreenland land and ice sheet streams, outlets, and basins. Routing assumes k = 0.9 for subglacial routing algorith
Streams, Outlets, and Basins [k=0.8]
No full textGreenland land and ice sheet streams, outlets, and basins. Routing assumes k = 0.8 for subglacial routing algorith
Mapping the hydrological system of the Greenland ice sheet in coarse satellite products with a machine learning approach
No full textThis paper utilizes supervised machine learning approach to infer presence of water features in Moderate Resolution Imaging Spectroradiometer imagery of Greenland ice sheet in the area UPE_U PROMICE automatic weather station (AWS). Reference dataset consisted of water feature mask was extracted from high resolution LANDSAT 8 images and co-located with MODIS imagery to fit the Gradient Boosting Decision Tree model. Despite a highly imbalanced dataset and difficult task, model obtained recall of 28.7% and precision of 40.1% for the water feature class and overall F1 Score of 96.5%. Then, the model was used to produce water masks over the period of time from 2000 to 2012. Obtained results showed a positive correlation with the average air temperature in-situ measurements and moderate consistency along entire period with other research studies. The study shows promising results for the use of machine learning for water feature extraction and suggests using different approaches to enhance results. The code accompanying this project is available in the author’s Github repository
Data methods applied in the Greenland diamond exploration package. Ministry of Mineral Resources Report, Government of Greenland, 56 pp.
No full textThe Report describes the structure and controls in formulating the Government of Greenland’s Diamond exploration data package. The structure and methodologies of attribution meet international standards applied in diamond exploration.
The database compiles over 50 years of diamond exploration data and expands beyond samples derived from Greenland’s established areas of diamondiferous rocks in central West Greenland to include a country-wide coverage of regional exploration data. The Diamond exploration data package is the first of its kind to collate diamond exploration data country-wide in a publicly accessible fashion. It incorporates the locations of 25 000 diamond exploration samples and over 109 000 good-quality chemical analyses of mineral separate grains integrated into a standardised framework. One hundred discrete, named in-situ bodies, which have diamond potential (kimberlites, lamproites, ultramafic lamprophyres, and carbonatites) are included. These occur among over 3 000 compiled in situ occurrences of dykes, pipes, sills and blows. With considerable data generated from bulk sampling of diamondiferous bodies, notably Garnet Lake, Qeqertaa and Majuagaa, this part of the database considerably expands upon previous compilations of relevant Greenland rocks. For chronological context, 56 emplacement age determinations from 36 bodies are also reported, encompassing most of the geographic extent of Greenland’s known rocks with diamond potential.
The Report describes the application of mineral chemical classification, addresses assumptions in application of petrological terms and the challenges presented by reporting of non-standardised data from multiple sources. By describing the formulation of the data package, it is intended that the user is able to more intelligently query and apply the data package content to further research and exploration. Furthermore, the Report acts as a template for application in future diamond exploration activities elsewhere
Discharge measurement at the outlet stream of Qaanaaq Glacier in the summer 2017−2019
No full textData comes from Ken Kondo and Shin Sugiyama at the Institute of Low Temperature Science, Hokkaido University, Japan. Additional details on the data collection can be found in the DischargeMeasurement200214.pdf file in this dataset
Gauge location: 77.475273975 N, -69.303039228