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Greenland Ice Velocity from Sentinel-1 Edition 4
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: 200 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, 1B and 1C 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 Edition 4:
The product resolution is now 200 m
Improved delineation of the velocity field at outlet glacier margins.
More details on the updated processor to be described in a planned update of the PROMICE ice velocity ESSD publication.
NOTE version 18: The products cycle314_315 through cycle318_319 have been updated. Some tracks were missing in the previous versions.
Main updates for Edition 3:
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.
NOTE: 6 day pairs in mosaics are back since end of March 2025:
We now also include data from Sentinel-1 C in the mosaics.
How to cite:
When using the dataset please use: Anne Solgaard; Anders Kusk, 2021, "Greenland Ice Velocity from Sentinel-1 Edition 4", 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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Large-scale Modeling of the Greenland Ice Sheet on Long Timescales
No full textThe stability of the Greenland ice sheet has global implications through sea level. Even smaller reductions in ice-sheet size can raise sea level enough to lead to complications for societies worldwide. In this work, the stability and evolution of the Greenland ice sheet on long timescales is investigated as well as its early history. The studies are performed using an ice-sheet model in combination with relevant forcing from observed and modeled climate. Computationally fast, adaptive forcing patterns were constructed. They take into account that the forcing patterns change in a non-uniform way in response to changes in ice-sheet geometry and climate. Using these patterns, the temperature threshold of irreversible decay of the ice sheet is found to lay 4-5 K above present levels, but when basal sliding is accounted for in the ice-sheet model it is shifted towards colder temperatures. How much depends on the choice of basal sliding formulation. The regrowth of the Greenland ice sheet after complete disintegration is found to be inhibited by a Föhn effect which increases temperatures in the interior Greenland. The early history of the Greenland ice sheet is also studied, and the great variability in ice-sheet geometry in the Pliocene to early Pleistocene is demonstrated. The effects of a hypothesis about mountain building in Greenland on ice sheet initiation are investigated. According to this, the present-day Greenland topography was formed during 2 phases of uplift since the late Miocene. Our simulated ice sheets are in line with geologic observations, and the uplift enhances the effect of the long-term climatic cooling over the period for ice sheet initiation in Greenland. Output of temperature and precipitation from the climate model, EC-EARTH, is investigated and a method for inferring Greenland precipitation anomalies from the large-scale circulation-patterns is tested. We find that it describes South Greenland precipitation well despite shortcomings due to mathematical constraints.The stability of the Greenland ice sheet has global implications through sea level. Even smaller reductions in ice-sheet size can raise sea level enough to lead to complications for societies worldwide. In this work, the stability and evolution of the Greenland ice sheet on long timescales is investigated as well as its early history. The studies are performed using an ice-sheet model in combination with relevant forcing from observed and modeled climate.Changes in ice-sheet geometry influences atmospheric flow (and vice versa) hereby changing the forcing patterns. Changes in the overall climate also alter the patterns. On this basis, output from a climate model is used to construct adaptive forcing patterns that are computationally fast and takes into account that the patterns respond to changes in a non-uniform way both spatially and temporally. The adaptive patterns were applied to study the steady-state response of the Greenland ice sheet to a warmer climate.The threshold of irreversible decay was found to lie between a temperature increase of 4-5 K relative to present day when basal sliding was neglected in the ice-sheet model. Introducing basal sliding into the ice-sheet model shifted this threshold towards colder temperatures in line with a recent study, but the new threshold value depends on the choice of method.It was found using the adaptive patterns that the Greenland ice sheet can reform under present-day conditions. A further study where additional coupling between the ice-sheet model and climate model is included shows, however, that a Föhn effect is activated and hereby increasing temperatures inland and inhibiting further ice-sheet expansion into the interior. This indicates that colder than present temperatures are needed in order for the ice sheet to regrow to the current geometry, and it is thus bistable under present day conditions.The Greenland ice sheet in the Pliocene is also studied, and the great variability in ice-sheet size during the period is demonstrated. The effects of a new hypothesis abot mountain building in Greenland on ice-sheet initiation are also investigated. Accordingto this hypothesis, two stages of uplift since the Late Miocene lead to the present-day topography. The results of the ice-sheet simulations show geometries in line with geologicobservations through the period, and it is found that the uplift events enhance the effect of the climatic deterioration for the build-up of the Greenland ice sheet that lead to the intensification of the Northern Hemisphere glaciations at the end of the Pliocene.A study of output from the climate model, EC-EARTH, reveals some of the challenges faced when using this to force ice-sheet evolution or when full coupling of ice-sheet models and climate models is desired. Precipitation is generally difficult for models to simulate. A method was tested where precipitation in Greenland is inferred from the large-scale circulation-patterns using principal component analysis. The method has limitations, but is able to predict the precipitation variability in South Greenland fairly well
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Multistability of the Greenland ice sheet and the effects of an adaptive mass balance formulation
No full textAppropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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