Pine island glacier iceberg – From a Glaciers Perspective

NASA MODIS Image from Sept. 24, 2015 showing new iceberg at calving front of Pine Island Glacier, Antarctica
In the MODIS images from the NASA Rapid Response image sets below you can see the lack of rifting in February, 2015 and April, 2015 that will lead at the calving front where the iceberg will break off that is evident on Sept. 24, 2015. A new iceberg was reported having calved by the US National Ice Center in August, labelled B-35, it was reported to be 12.66 miles (20.4 km) long by 8 miles (12.8 km) wide. The iceberg indicated in the Sept. 24 image is not B-35. It is much smaller than B-31 that broke off in 2013, but is approximately 14 km long and 8 km wide. There are two other icebergs indicated that also broke off over the winter from Pine Island Glacier, into the polyna.

As Operation IceBridge begins its 2015 southern campaign I am sure we will learn much more about this iceberg. Details on the 2013 Calving illustrate a slower process from rift formation to calving. Pine Island Glacier is remains a key glacier that is undergoing rapid change.

Operation Icebridge kept an eye this past fall on the extensive rift transecting the PIG that will lead to calving of a large iceberg in the near future. This rift was identified by NASA’s Operation Icebridge in 2011. This rift expanded laterally through 2012 and in width in early 2013, but had not shown open water in the daily MODIS imagery until 11/11/2013. The iceberg had not detached fully from the glacier until now. The iceberg being calved is approximately 780 square kilometers in size. With the Antarctic Operation Ice Bridge just beginning a new campaign great imagery will soon come via Pine Island Glacier I am sure.

Below is the image from Nov. 11 & 16 2013 annotated followed by a sequence of MODIS images of the rift in 2012 and 2013 from the MODIS Rapid Ice Sheet Change Repository for Antarctica updated daily.

Nov. 11, 2013 MODIS

Nov. 16 2013 MODIS

Feb. 4, 2012 MODIS

March 9, 2012 MODIS

Nov. 19 2012 MODIS

Dec. 25 2012 MODIS

Feb. 2 2013 MODIS

Feb. 9, 2013 MODIS

Feb 18, 2013 MODIS

April 3, 2013 MODIS

Oct. 23, 2013 MODIS

Nov. 5, 2013 MODIS

Nov. 11, 2013 MODIS

Landsat Image from March 2013, indicating the rift, before separation including additional rifts forming on east margin.

This iceberg can be compared to the development of an iceberg in 2001 (NASA 2001).

On December 17, 2012 researchers with the PIG project announced that they had successfully drilled through the remote Pine Island Glacier ice shelf.
The successful drilling will help to reach the project’s ultimate objective: to study the physical processes that are causing a rapid melting of the 60-kilometer-long (37 miles) ice shelf that extends into Pine Island Bay. One cause is suspected to be the circulation of relatively warmer ocean waters under the floating ice shelf that are undercutting the shelf (NSF, 2012). The logistics of this operation is captured in fascinating detail by the PIG Ocearnography Program. Meanwhile the Glaciology Program under Bob Bindshacler of NASA will be sizing up the glacier. PIG has thinned and accelerated since 1984, the most notable cause is melting of the base of ice sheet by warm water that was directly measured using and autosub (Jenkins et al, 2011). This research led to observations of channelized melt beneath the glacier (Stanton et al 2013).