*************README.txt*************

Title: Neogene–Quaternary uplift and landscape evolution in northern Greenland recorded by subglacial valley morphology: Datasets

Digital Object Identifier: 10.5281/zenodo.5648042

Associated publication: Paxman, G. J. G., Tinto, K. J., Austermann, J. (2022) Neogene–Quaternary uplift and landscape evolution in northern Greenland recorded by subglacial valley morphology. Journal of Geophysical Research: Earth Surface
doi: 10.1029/2021JF006395

Link to publication: https://doi.org/10.1029/2021JF006395

Suggested citation: Please reference the associated publication above when using this dataset.

Funding: This research was supported by the U.S. National Science Foundation (Navigating the New Arctic).
'NNA Track 1: Predicting coastal responses to a changing Greenland ice sheet.'
Grant number: ICER 19-28146.

Contact information: Please direct any queries to Guy Paxman, Lamont-Doherty Earth Observatory, Columbia University, USA (gpaxman@ldeo.columbia.edu).

************************************

This directory contains the following data files.

northern_Greenland_valley_morphology.csv
northern_Greenland_valley_network.cpg
northern_Greenland_valley_network.dbf
northern_Greenland_valley_network.prj
northern_Greenland_valley_network.qpj
northern_Greenland_valley_network.shp
northern_Greenland_valley_network.shx

More detailed information about each of these datasets is found in the following sections.

************************************

RADAR-DERIVED VALLEY MORPHOLOGY

northern_Greenland_valley_morphology.csv is a comma-separated values file containing the location and morphology of subglacial valleys in northern Greenland, as imaged by airborne radio-echo sounding datasets.

The fields in this file are as follows:

1) Flight number. Code describing the Operation IceBridge (or earlier) frame ID (flight number, segment, and frame). The frame ID follows the format YYYYMMDDSSFFF where YYYY is the 4-digit year, MM is the 2-digit month from 1 to 12, DD is the 2-digit day of the month from 1 to 31, SS is the segment number from 0 to 99, and FFF is the frame number from 000 to 999.

2) Longitude. WGS-84 geodetic longitude coordinate [decimal degrees]. Always referenced to East.

3) Latitude. WGS-84 geodetic latitude coordinate [decimal degrees]. Always referenced to North.

4) x_PS (m). x coordinate [metres] in EPSG:3413 projection (WGS84 / NSIDC Sea Ice Polar Stereographic North).

5) y_PS (m). y coordinate [metres] in EPSG:3413 projection (WGS84 / NSIDC Sea Ice Polar Stereographic North).

6) Top elevation (m WGS84). Mean elevation of the valley top [metres], relative to the WGS84 ellipsoid.

7) Floor elevation (m WGS84). Elevation of the valley floor [metres], relative to the WGS84 ellipsoid.

8) Ice rebound (m). Isostatic rebound due to ice unloading [metres] (positive = up).

9) Fjord erosion correction (m). Isostatic response to fjord erosion [metres] (positive = up).

10) Geoid correction (m). Correction to convert elevations from relative to the WGS84 ellipsoid to relative to mean sea level [metres] (using the geoid EIGEN-6C4).

11) Rebounded top elevation (m). Mean elevation of the valley top [metres] corrected for glacial loading and erosional isostatic effects, and relative to mean sea level (fields 6 + 8 - 9 - 10).

12) Rebounded floor elevation (m). Elevation of the valley floor [metres] corrected for glacial loading and erosional isostatic effects, and relative to mean sea level (fields 7 + 8 - 9 - 10).

13) Top width (m). Width of the top of the valley [metres].

14) Depth (m). Mean depth of the valley [metres], defined as fields 11 - 12.

15) Channel dam flag. Flag that can be used to isolate the points of the valley infilled by a sediment dam. 0 = channel dam; 1 = regular valley floor with no infill.

************************************

SUBGLACIAL VALLEY NETWORK

northern_Greenland_valley_network.shp (and ancillary files: .cpg, .dbf, .prj, .qpj, .shx) is an ESRI shapefile of the interpreted valley network in the northern Greenland subglacial drainage catchment.

The file is projected in EPSG:3413 (WGS84 / NSIDC Sea Ice Polar Stereographic North). It contains line features for the mapped valley network. Each line feature contains an attribute called 'Order', which takes a value between 1 and 5. This describes the Strahler stream order of each tributary, which refers to the number and complexity of upstream branches in the valley network.  

************************************