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Supplementary files for: The karst and palaeokarst of North and North-East Greenland – physical records of cryptic geological intervals
No full textCarbonate rocks of Neoproterozoic to Silurian age are abundantly distributed around the coasts of North and North-East Greenland. Palaeokarst horizons are particularly well-developed within the Portfjeld Formation (Ediacaran – earliest Cambrian) and beneath the Buen Formation (Cambrian Series 2), and there are caves within Ordovician limestones infilled by Caledonian molasse of Middle Devonian age. The youngest karst is a series of caves distributed from Hall Land in western North Greenland to Kronprins Christian Land in eastern North Greenland. Caves within Ordovician carbonates in Freuchen Land are currently the northernmost documented karst caves globally. The caves are mainly open phreatic conduits, any fill that is present is unlithified, and cave collapse is limited to minor breakdown associated with frost shattering. These geologically young caves are consistently located up to a few hundred metres beneath the distinctive plateau that characterises the topography of the northern coast, and their identical context suggests that they developed in a single phase of speleogenesis. The caves are exposed where the plateau has been incised by outlet glaciers from the Greenland ice sheet. The timing of cave development in North Greenland is constrained by the mid- to late Miocene (15–5 Ma) uplift of the plateau surface and the onset of fjord-forming glaciation in the latest Pliocene – earliest Pleistocene (c. 2.7–2.5 Ma). The evidence suggests that phreatic caves in the southern part of North-East Greenland, on C. H. Ostenfeld Nunatak, are of a broadly similar age. The caves of North and North-East Greenland offer a glimpse of large-scale phreatic drainage systems that developed below an uplifted coastal peneplain during Neogene time. They preserve an important part of the geological history of North and North-East Greenland that is otherwise absent from the physical geological record
DK-model2019 - modelsetup (area: DK4, DK5, DK6)
No full textThis .zip file contains DK-model2019, area DK4, DK5 and DK6 (Jylland), as a coupled MIKE SHE/MIKE HYDRO River model setup.
The National Hydrologiske Model (DK-Model) is set up in the MIKE SHE/MIKE HYDRO River model system, which constitutes a deterministic fully distributed and physically based model complex for simulating the freshwater cycle. The model includes a description of the surface runoff (OL), the unsaturated zone (UZ), the saturated groundwater zone (SZ), including drainage runoff, as well as water flow in the streams (MIKE HYDRO River). The numerical hydrological model is set up in a discretization of 500 x 500m grid for the whole country, except for Bornholm, which is set up with a discretization of 250x 250m
Supplementary files for: Long short-term memory networks enhance rainfall-runoff modelling at the national scale of Denmark
No full textThis study explores the application of long short-term memory (LSTM) networks to simulate runoff at the national scale of Denmark using data from 301 catchments. This is the first LSTM application on Danish data. The results were benchmarked against the Danish national water resources model (DK-model), a physically-based hydrological model. The median Kling-Gupta Efficiency (KGE), a common metric to assess performance of runoff predictions (optimum of 1), increased from 0.7 (DK-model) to 0.8 (LSTM) when trained against all catchments. Overall, the LSTM outperformed the DK-model in 80% of catchments. Despite the compelling KGE evaluation, the water balance closure was modelled less accurately by the LSTM. The applicability of LSTM networks for modelling ungauged catchments was assessed via a spatial split-sample experiment. The performance for a 20% hold-out showed poorer performance of the LSTM with respect to the DK-model. However, after pre-training, i.e. weight initialisation obtained from training against simulated data from the DK-model, the performance of the LSTM was effectively improved. This formed a convincing argument supporting the knowledge-guided machine learning paradigm to integrate physically-based models and machine learning to train robust models that generalise well
Greenland Ice Velocity from Sentinel-1 Edition 3
No full text Greenland Ice Velocity from Sentinel-1
The PROMICE Ice Velocity product is a timeseries of Greenland Ice Sheet velocity mosaics based on ESA Sentinel-1 SAR offset tracking.
The product spans the period January 2016 to present.
Spatial resolution: 500 m
Temporal resolution: A new mosaic spanning 2 Sentinel-1A cycles i.e. 24 days is posted every 12 days.
Each mosaic: All possible 6 and 12 day pairs using Sentinel-1A and 1B is included in the mosaic.
Each mosaic is supplied as a NetCDF file.
Projection: Polar Stereographic projection (EPSG: 3413)
The data product is described in detail in Solgaard et al., 2021 (see reference below)
We aim to make each new mosaic available within 10 days of the last included acquisition.
To see and post comments/recommendations please check out: github.com/GEUS-PROMICE/Sentinel-1_Greenland_Ice_Velocity
Main updates for this Edition:
The dataset has been extended back in time and now covers: January 2016 - Present
Main updates performed for Edition 2:
All 6 day and 12 day pairs possible are included in each 2 cycle mosaic.
We no longer mask out results in ice free areas in order to avoid removing ice flow as the ice sheet advances
We apply the culling scheme described in Solgaard, A., Kusk, A., Merryman Boncori, J. P., Dall, J., Mankoff, K. D., Ahlstrøm, A. P., Andersen, S. B., Citterio, M., Karlsson, N. B., Kjeldsen, K. K., Korsgaard, N. J., Larsen, S. H., and Fausto, R. S.: Greenland ice velocity maps from the PROMICE project, Earth Syst. Sci. Data, 13, 3491–3512, https://doi.org/10.5194/essd-13-3491-2021, 2021.
NOTE: From version 11: Prior to version 11, the mosaics covering dates in 2021 were not culled correctly. In version 11 the affected mosaics have been re-culled and uploaded.
NOTE: From version 31:Prior to version 31, there were gaps in the timeseries in 2017. These have now been filled.
NOTE: No 6 day pairs in mosaics since Dec 23 2021:
Due to a faliure on Sentinel-1 B, no data has been received from the satellite since Dec 23 2021. For this reason the mosaics produced since then includes no 6 day pairs. This limits the quality of the posted ice velocity mosaics.
How to cite:
When using the dataset please use: Anne Solgaard; Anders Kusk, 2021, "Greenland Ice Velocity from Sentinel-1 Edition 3", https://doi.org/10.22008/promice/data/sentinel1icevelocity/greenlandicesheet, GEUS Dataverse
Literature citation: Solgaard, A., Kusk, A., Merryman Boncori, J. P., Dall, J., Mankoff, K. D., Ahlstrøm, A. P., Andersen, S. B., Citterio, M., Karlsson, N. B., Kjeldsen, K. K., Korsgaard, N. J., Larsen, S. H., and Fausto, R. S.: Greenland ice velocity maps from the PROMICE project, Earth Syst. Sci. Data, 13, 3491–3512, https://doi.org/10.5194/essd-13-3491-2021, 2021.
Please add the following to your acknowledgements: "Ice velocity maps were produced as part of the Programme for Monitoring of the Greenland Ice Sheet (PROMICE) using Copernicus Sentinel-1 SAR images distributed by ESA, and were provided by the Geological Survey of Denmark and Greenland (GEUS) at http://www.promice.dk."
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Redoxmaps from CRES2016
No full textResulting redoxmaps from the paper https://doi.org/10.5194/hess-2020-570. Maps are given for 45 combinations of 4 land use scenarioes, observational land use and climate data, and four different future climate models. Please see publication for details
PROMICE-1980s Ice Mask
No full textThis dataset contains fractional ice cover across Greenland at 1 km and 5 km spatial resolutions. This fractional ice cover is derived from analysis of an aerophotogrammetric map of Greenland acquired mostly between 1978 and 1987. Ice cover is classified as "ice sheet" or "local ice mass", with local ice mass further classified as either "connected" or "disconnected" from the ice sheet
Video abstract - Towards green Arctic fjords
No full textVideo abstract "Towards green Arctic fjords" by Underground Channel.
Relates to Oksman et al. study on the impacts of Greenland ice sheet freshwater runoff on the marine ecosystem published in The Cryosphere
Supporting codes and data for GRL study - Greenland Ice Sheet Rainfall, Heat and Albedo Feedback Impacts from the Mid-August 2021 Atmospheric River
No full textin compliance with AGU journal requirements, a tar.gz file contains data and codes used in this study
Calving front line
No full textMarine terminating outlet glacier calving front lines. We update a collection of annual end-of-melt-season calving front lines for 47 of the largest Greenland outlet glaciers. The Greenland calving front lines are based on optical satellite imagery from Landsat, Aster, and Sentinel-2. The end-of-melt-season calving front line product is available as ESRI shapefiles
GC-Net Level 1 historical automated weather station data
No full textGC-Net Level 1 automated weather station data
In Memory of Dr. Konrad (Koni) Steffen
Author: B. Vandecrux
Contact: [email protected]
Last update: 2023-09-01
Citation
Steffen, K.; Vandecrux, B.; Houtz, D.; Abdalati, W.; Bayou, N.; Box, J.; Colgan, L.; Espona Pernas, L.; Griessinger, N.; Haas-Artho, D.; Heilig, A.; Hubert, A.; Iosifescu Enescu, I.; Johnson-Amin, N.; Karlsson, N. B.; Kurup Buchholz, R.; McGrath, D.; Cullen, N.J.; Naderpour, R.; Molotch, N.P.; Pederson, A. Ø.; Perren, B.; Philipps, T.; Plattner, G.K.; Proksch, M.; Revheim, M. K.; Særrelse, M.; Schneebli, M.; Sampson, K.; Starkweather, S.; Steffen, S.; Stroeve, J.; Watler, B.; Winton, Ø. A.; Zwally, J.; Ahlstrøm, A., 2023, "GC-Net Level 1 automated weather station data", https://doi.org/10.22008/FK2/VVXGUT, GEUS Dataverse, V3
as described and processed by:
Vandecrux, B., Box, J. E., Ahlstrøm, A. P., Andersen, S. B., Bayou, N., Colgan, W. T., Cullen, N. J., Fausto, R. S., Haas-Artho, D., Heilig, A., Houtz, D. A., How, P., Iosifescu Enescu, I., Karlsson, N. B., Kurup Buchholz, R., Mankoff, K. D., McGrath, D., Molotch, N. P., Perren, B., Revheim, M. K., Rutishauser, A., Sampson, K., Schneebeli, M., Starkweather, S., Steffen, S., Weber, J., Wright, P. J., Zwally, H. J., and Steffen, K.: The historical Greenland Climate Network (GC-Net) curated and augmented Level 1 dataset, Earth Syst. Sci. Data, 15, 5467–5489, https://doi.org/10.5194/essd-15-5467-2023, 2023.
Description
The Greenland Climate Network (GC-Net) is a set of Automatic Weather Stations (AWS) set up and managed by the late Prof. Dr. Konrad (Koni) Steffen on the Greenland Ice Sheet (GrIS). This first station, "Swiss Camp" or the "ETH-CU" camp, was initiated in 1990 by A. Ohmura et al. (1991, 1992) with K. Steffen taking over the site from 1995 and expending the network from that year to 31 stations at 30 sites in Greenland (Steffen et al., 1996, 2001). The GC-Net was supported by multiple NASA, NOAA, and NSF grants throughout the years, and then supported by WSL in the later years. These data were previously hosted by the Cooperative Institute for Research in Environmental Sciences (CIRES) in Boulder, Colorado.
Provided in this dataset are the 25 two-level stations from 24 sites on the Greenland ice sheet and 3 experimental stations in Antarctica. The remaining 6 Greenland stations have a different design and will be added once quality checked. Although the GC-Net AWS transmitted their data near-real time through satellite communication, the present dataset was made from uncorrupted datalogger files, retrieved every 1-2 years during maintenance.
Full dataset description publication will be forthcoming. The Geological Survey of Denmark and Greenland (GEUS) has undertaken the continuation of multiple GC-Net sites through the Programme for Monitoring of the Greenland Ice Sheet (PROMICE.dk).
The level 1 data is provided in the newly described csv-compatible NEAD format, which is a csv file with added metadata header. The format is documented at https://doi.org/10.16904/envidat.187 and a python package is available to read and write NEAD files: https://github.com/GEUS-Glaciology-and-Climate/pyNEAD .
The GC-Net stations measure:
- Air temperature from four sensors at two heights above the surface
- Relative humidity at two heights above the surface
- Wind speed and direction at two heights above the surface
- Air pressure
- Surface height from two sonic sounders
- Incoming and outgoing shortwave radiation
- Net radiation (long- and short-wave)*
- Firn or ice temperatures at 10 levels below the surface
In the L1 dataset, these measurements are cleaned from sensor, station or logger malfunctions, adjusted and/or filtered when and where possible.
Additionally, the L1 dataset contains the following derived variables:
- Surface height (corrected from the shifts in sonic sounder height)
- Instrument heights (derived from sonic sounder height and station geometry)
- Inter- or extrapolated temperature, relative humidity and wind speed at respectively 2, 2, and 10 m above the surface
- Estimated depth of the subsurface temperature measurements (adjusted for snow accumulation, ice ablation and instrument replacement)
- Interpolated firn or ice temperature at 10 m below the surface
- Calculated solar an azimuth angles
- Sensible and latent heat fluxes calculated after Steffen and Demaria (1996)
Important links:
- The level 1 processing scripts and discussion page for Q&A and issue reporting (under "issues" tab) is available at: https://github.com/GEUS-Glaciology-and-Climate/GC-Net-level-1-data-processing
- The level 0 data (from which the L1 data was built from) is available at: https://www.doi.org/10.16904/envidat.1.
- The compilation of handheld GPS coordinates for each site and for multiple years is available here: Vandecrux, B. and Box, J.E.: GC-Net AWS observed and estimated positions (Version v1) [Data set]. Zenodo. https://doi.org/10.5281/zenodo.7729070, 2023c.
- The compilation of field pictures is available at: Box, J.E., Vandecrux, B., Houtz, D., Steffen, K.: GC-Net historical photo archive, https://doi.org/10.5281/zenodo.7839788, 2023b
- The compilation of useful metadata (reports, field notes...) is available at: Vandecrux, B., Houtz, D., Box, J.E.: GC-Net historical metadata compilation [Data set]. Zenodo, https://doi.org/10.5281/zenodo.7728549, 2023b.
Acknowledgments:
In addition to the support from several past NASA and NSF grants awarded to K. Steffen (grant nr. NAPW-2158, NAG51-1612, NAG5-10600, NAG5-10857, NNG06GB08G, OPP-9423530), financial support of the 2020 transition came from the DANCEA (Danish Cooperation for Environment in the Arctic) under the Danish Ministry of Energy, Buildings and Climate. The Danish Finance Law currently supports the GC-Net field and data activities. We acknowledge the key contributions from all the people that have participated in the GC-Net project, assisted Konrad Steffen through the years and contributed to the longevity of GC-Net. In particular, we acknowledge (in alphabetical order) the support from Robin Abbott, Waleed Abdalati, Todd Albert, Kate Daniels, Lucia Espona Pernas, Nena Griessinger, Alain Hubert, Russell Huff, Nighat Johnson-Amin, Mike MacFerrin, Molly McCallister, Reza Naderpour, Atsumu Ohmura, Allan Ø. Pedersen, Thomas, Philipps, Gian-Kasper Plattner, Kim Petersen, Martin Proksch, Christian Schneeberger, Christopher Shields, Martina Særrelse, Julienne Stroeve, Benjamin Walter, Øyvind A. Winton and many others.
References:
Ohmura, A., Steffen.K., Blatter, H., Greuell, W., Rotach.M., Konzelmann,T., Laternser.M., Abe-Ouchi, A. and Steiger, D. (1991) Energy and mass balance during the melt season at the equilibrium line altitude, Paakitsoq, Greenland ice sheet. ETH Greenland Expedition Prog. Report no. 1, Dept of Geography, Swiss Fed. Inst, of Technol., Zurich.
Ohmura, A., Steffen, K., Blatter, H., Greuell, W., Rotach.M., Konzelmann,T., Forrer, J., Abe-Ouchi, A., Steiger.D., Stober, M. and Niederbàumer, G. (1992) Energy and mass balance during the melt season at the equilibrium line altitude, Paakitsoq, Greenland ice sheet. ETH Greenland Expedition Prog. Report no. 2, Dept of Geography, Swiss Fed. Inst, of Technol., Zurich.
Steffen, K., & deMaria, T. (1996). Surface Energy Fluxes of Arctic Winter Sea Ice in Barrow Strait, Journal of Applied Meteorology and Climatology, 35(11), 2067-2079. Retrieved Feb 15, 2023, https://doi.org/10.1175/1520-0450(1996)035<2067:SEFOAW>2.0.CO;2
Steffen, K., Box, J.E. and Abdalati, W., 1996. Greenland climate network: GC-Net. US Army Cold Regions Reattach and Engineering (CRREL), CRREL Special Report, pp.98-103.
Steffen, K., and Box, J. (2001), Surface climatology of the Greenland Ice Sheet: Greenland Climate Network 1995–1999, J. Geophys. Res., 106( D24), 33951– 33964, https://doi.org/10.1029/2001JD900161.
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