Monday, 9 July 2018

MIMO: Monitoring sub-shelf melt where ice meets ocean

Ice shelves – the floating extensions of ice sheets - play a crucial role in controlling the present-day mass loss of the Antarctic ice sheet. Basically, ice shelves act as a cork on a bottle and restrain the inland ice through what is known as buttressing. Ice-shelf change is particularly pronounced in West Antarctica in response to increased oceanic heat transport beneath its floating ice shelf and resulting feedbacks, but evidence from around Antarctica confirms that the effect is not geographically limited. Ice-shelf thinning causes an instantaneous acceleration and a retreat of the grounding-line (limit between the grounded ice sheet and the floating ice shelf), hence a rise in sea level, which has major consequences for society.

One difficulty in studying Antarctic ice shelves arises from their unsteady nature. The ice geometry is evolving rapidly (years), ice is being advected at speeds >1 km/yr whilst the ocean beneath is expected to respond at sub-annual scales. In addition, there are many reasons to expect that the spatial pattern of melt is complex, where sub-shelf melting is concentrated in weaker zones of ice shelves, such as longitudinal bottom channels. Only a few studies have been focused on the spatial pattern, which requires high-resolution interferometrically-determined ice flow velocities and surface elevation and changes herein. Their application therefore remains limited to specific ice shelves or ice shelf sections for a particular snapshot in time, which is not useful for wider mapping, monitoring and impact assessment, which will be addressed in MIMO.

More info on the project, on the MIMO tab.

Monday, 4 July 2016

Warmer winter?

It seems like a warmer winter this year, but probably not. The temperatures of the radar sensors are significantly higher than last year. However, my position has changed. I am now installed close to the grounding line, an area where surface melt is predominant, and I feel it as well!

The GPS station are still at the same position of last year. However they moved with the motion of the ice shelf. Almost 500 m in less than 600 days.

GPS CGEO: my current position is 70.3999S, 25.0289E. I moved 471.6803m in direction N248.4208E in 571.9167 days.



GPS CDS: my current position is 70.4062S, 24.9927E. I moved 445.1747m in direction N248.9637E in 572.2083 days.


Sunday, 17 January 2016

Hello: I am back in business, despite a small data gap :-)

GPS CDS: my current position is 70.4073S, 24.9939E. I moved 313.121m in direction N248.8688E in 403.7083 days.



GPS CGEO: my current position is 70.4011S, 25.0302E. I moved 331.5652m in direction N248.4636E in 403.4167 days.


Tuesday, 22 December 2015

GPS CDS: my current position is 70.4075S, 24.994E. I moved 290.8009m in direction N248.5887E in 377 days.




Friday, 6 November 2015

GPS CDS: my current position is 70.4078S, 24.9944E. I moved 254.29m in direction N248.5234E in 330.5 days.
GPS CGEO: my current position is 70.4016S, 25.0307E. I moved 273.8975m in direction N248.2835E in 330.5 days.



Monday, 31 August 2015

GPS CDS: my current position is 70.4082S, 24.9948E. I moved 204.8561m in direction N338.7133E in 264 days.

GPS CGEO: my current position is 70.402S, 25.0312E. I moved 218.6968m in direction N338.1188E in 264 days.

Monday, 6 July 2015

GPS CDS: my current position is 70.4085S, 24.9952E. I moved 162.3373m in direction N338.4979E in 208.5 days.

GPS CGEO: my current position is 70.4024S, 25.0316E. I moved 172.6809m in direction N338.1068E in 208.5 days.

Thursday, 7 May 2015

GPS CGEO: my current position is 70.4028S, 25.0321E. I moved 123.7642m in direction N338.4082E in 148 days.


GPS CDS: my current position is 70.4089S, 24.9956E. I moved 116.8179m in direction N338.5546E in 148 days.

Monday, 13 April 2015

GPS CDS: my current position is 70.4091S, 24.9957E. I moved 98.3514m in direction N338.1825E in 123.5 days.

GPS CGEO: my current position is 70.403S, 25.0322E. I moved 103.5835m in direction N338.2305E in 123.5 days.



Wednesday, 1 April 2015

GPS CDS: my current position is 70.4092S, 24.9959E. I moved 88.1817m in direction N340.1458E in 112 days.
GPS CGEO: my current position is 70.4031S, 25.0323E. I moved 94.1208m in direction N338.9636E in 112 days.

Wednesday, 18 February 2015

GPS CDS: my current position is 70.4095S, 24.9961E. I moved 54.2068m in direction N338.1332E in 70 days.

GPS CGEO: my current position is 70.4034S, 25.0327E. I moved 58.5586m in direction N337.9529E in 70 days.

Friday, 6 February 2015

GPS CDS: my current position is 70.4095S, 24.9962E. I moved 45.106m in direction N338.3075E in 58 days.

GPS CGEO: my current position is 70.4035S, 25.0328E. I moved 48.9206m in direction N338.7109E in 58 days.

Monday, 2 February 2015

GPS CDS: my current position is 70.4096S, 24.9962E. I moved 42.5893m in direction N338.1442E in 54 days.

GPS CGEO: my current position is 70.4035S, 25.0328E. I moved 46.0487m in direction N338.5234E in 54 days.


Tuesday, 27 January 2015

GPS CDS: my current position is 70.4096S, 24.9963E. I moved 37.1782m in direction N337.7443E in 48 days.

GPS CGEO: my current position is 70.4035S, 25.0328E. I moved 40.2386m in direction N339.0665E in 48 days.
For graphical output, see the new page 'GPS positions'
 

Friday, 16 January 2015

New positions and analyses

GPS CGEO: my current position is 70.4036S, 25.0329E. I moved 30.2055m in direction N339.5111E in 37 days. As the figure below shows, there is some relation of the horizontal displacement with the tides. At least the frequency is he same, but a phase shift is noticeable. Nevertheless, these are still raw data. Waiting to get a longer time series.



The temperatures of the sensors have been going down recently, the system is now at approximately -10°C.

Friday, 2 January 2015

GPS CDS: my current position is 70.4098S, 24.9965E. I moved 17.3673m in direction N338.8072E in 23 days.

GPS CGEO: my current position is 70.4037S, 25.033E. I moved 18.2924m in direction N336.7964E in 23 days.




Monday, 29 December 2014

GPS CDS: my current position is 70.4098S, 24.9965E. I moved 14.4629m in direction N337.9899E in 19 days.
GPS CGEO: my current position is 70.4038S, 25.0331E. I moved 15.0737m in direction N337.3602E in 19 days.
CGEO is slightly faster than CDS, and that is what is expected ;-)

Friday, 26 December 2014

GPS CDS: my current position is 70.4098S, 24.9965E. I moved 12.4572m in direction N338.1174E in 16 days.

GPS CGEO: my current position is 70.4038S, 25.0331E. I moved 13.0883m in direction N339.0418E in 16 days.

Raw data on relative motion of GPS CGEO in the first 16 days of its deployment.