Survey to detect long-term variability in Pine Island Bay coastal Ice using archived Landsat Imagery

Elizabeth City State University
Elizabeth City, North Carolina 27909

Michael Jefferson Jr, Ryan Lawerence, Glenn Koch and Ya'Shonti Bridgers (Members)
Dr. Malcolm LeCompte (Mentor)

Antarctic Grounding Line Team

Abstract

In the 2003 Antarctic Surface Accumulation and Ice Discharge project, the Pine Island Bay Region was identified as an area to exhibit rapid changes potentially due to climate warming.

Utilizing the 2003 Antarctic Surface Accumulation and Ice Discharge basal stress boundary vector file, we surveyed the Pine Island Bay region from 100° West longitude to 112° West longitude to determine the accuracy of the grounding line and detect significant changes over multi-decadal time intervals.

Exelis Visualization Information Solutions' ENVI image processing software was used to co-register Landsat Muti-Spectral Scanner and Thematic Mapper images. Images prior to 2003 were co-registered with circa 2003 Landsat Ehanced Thematic Mapper used to created the 2003 Antarctic Surface Accumulation and Ice Discharge basal stress boundary. The survey yielded the possibility of one significant change in the placement of the basal stress boundary and instances of relatively minor basal stress boundary misplacement (or retreat) and evolutionary coastal ice retreat.

Undergraduate Research Experience in Ocean, Marine, and Polar Science
http://nia.ecsu.edu/ureomps2011/
Elizabeth City State University
Elizabeth City, North Carolina 27909

Ya' Shonti Bridgers, Jessica Brownlow, Kirsten Hawk (Members)
Dr. Malcolm LeCompte (Mentor)

Grounding Line Validation Team

Abstract

Dr. Robert Bindschadler, leading an international team of glaciologists and computer scientists including ECSU students, obtained an accurate measure of the area of the Antarctic ice sheet in order to determine whether the amount of ice is growing or diminishing over long time intervals.  The grounding line or boundary dividing the ice sheet resting on land from floating ice must be located before the ice sheet’s area can be determined. The grounding line’s location was determined by combining LANDSAT Enhanced Thematic Mapper (ETM) image brightness with surface elevation data obtained by the Geoscience Laser Altimeter System (GLAS) aboard NASA’s Ice, Land and Cloud elevation Satellite (ICESat) polar orbiting earth observatory.  LANDSAT brightness data spatially coincident with GLAS laser altimetry provided a means of correlating ground slope with known elevation. The elevation of the space between GLAS altimetry tracks were interpolated using slopes derived from LANDSAT surface brightness; a method called photo-clinometry.
The Grounding Line (GL) was established using 2003 data.  LANDSAT image data contemporary with the grounding line will be compared to earlier LANDSAT imagery of the same area. A small ice shelf near the eastern entrance to Pine Island Bay was previously identified as having diminished over an approximately 17-year span. The disappearance of this ECSU Ice Shelf has been qualitatively characterized.  The GL Validation Team will quantify the ice shelf area lost over time since its discovery in 1986.  The team will overlay the 2003 GL on LANDSAT 7 ETM 2003 imagery and calculate ice shelf area in the same scene previously recorded by the LANDSAT 4, 5 Thematic Mapper (TM) and LANDSAT-7 ETM.
LANDSAT Images from 2003 used in creating the GL will be obtained from the USGS archive (lima.usgs.gov and.  Next the older, cloud free LANDSAT TM and ETM images of the Pine Island Glacier region will be obtained from another USGS archive (glovis.usgs.gov). Image comparison will be accomplished using ITT’s Visualization System’s ENVI image processing software. Any departure from perfect geographic pixel registration will be corrected using the 2003 image as a reference and registering older images to conform to the common fixed control points visible on both images. The grounding line overlying the 2003 image will be used to compute the area changes in the ice shelf and the geographic coordinates and extent of any departures from coincidence will be recorded and reported. 
The objective of the project is three-fold: first provide Dr. Bindschadler with a detailed description of the disappearance of the ECSU Ice Shelf; second, to examine the 2003 grounding line’s correspondence to the actual terrain and third, seek the existence of features that may have undergone climate-related changes.