April 11, 2016

Nansen Ice Shelf, Antarctica Calving Event Occurs April 2016

Posted by Mauri Pelto

nansen compare calving

Nansen Ice Shelf just north of Dryglaski Ice Tongue on April 2 with evident rift,blue arrows, and after calving two icebergs on April 7, A and B. Images from NASA MODIS

The NIWA reported a calving event from the Nansen Ice Shelf on April 11, 2016.  They are concerned about a mooring in Terra Nova Bay in front of the ice shelves. The area of the Nansen Ice Shelf is 1500 square kilometers, these icebergs have a combined estimate of approximately 250 square kilometers.  This is a substantial calving event for such a small system. Below is an image of the Nansen Ice Shelf on January 1, 2014 and January 1, 2016.  This illustrates the Terra Nova Bay polyna that develops every summer, and affects sea ice dynamics, and certainly the ice shelf. The former lacks a notable rift, the latter exhibits the rift that would lead to calving, the rift had formed in late 2013, but is still not evident in imagery of the resolution of MODIS.  NIWA had been watching this expanding rift for signs of calving.  NASA had warned in March that calving was imminent and had been monitoring the ice shelf to determine the affect of tides on the ice shelf dynamics.  The rift is beautifully shown by NASA in its growth from 2013 to 2015. Such rifting and calving can be part of stable dynamics as on Stange Ice Shelf or an indicator of instability as in the case of Verdi Ice shelf.

nansen comapre

Nansen Ice Shelf in January 2014 and January 2016.

terra nova 1999

Google Earth image of the region in 1999 indicating several significant rifts.