Discovery Metadata System

Related Links

Summary

Abstract:
This is a collection of GPS data from dual-frequency GPS units deployed on the Filchner-Ronne Ice Shelf and adjoining ice streams. Filenames contain ice stream code and, in some cases, where the ice stream code is followed by a plus or minus sign, the approximate distance in kilometres upstream from the ice stream's grounding line, although in other cases the number is arbitrary. The naming convention has been preserved for legacy reasons. The ice streams are Evans (E & XX), Rutford (R), Institute (IIS), Talutis (T & TT) and Foundation (H) ice streams.

Each GPS unit's data are given in a netCDF4_classic file containing 4 columns: "Date number", as the number of days from January 0, 0000 in the proleptic ISO calendar; "Latitude" & "Longitude", both in decimal degrees in the WGS 1984 EPSG:4326 co-ordinate system; "height", in metres above the reference ellipsoid. The data have been collated from daily files, processed using the Bernese 5.0 software, using precise point positioning at intervals of 30 seconds. Note that data have not been corrected for inverse barometer or ocean tide loading effects.

These data were collected as part of a systemic campaign to look for modulation in ice flow through ocean tidal forcing. The vertical tidal motion of floating ice shelves generates stresses which cause a change in horizontal ice velocity at periods of hours to years. These signals can travel far upstream of ice stream grounding lines and often exhibit a change in frequency from the astronomical tides that generate them. As such, they can act as a natural experiment with which we can learn about ice rheology and subglacial processes.

Keywords:
Filcher-Ronne, GPS, Ice Shelf, Ice Stream