Paper Info
Title
Supraglacial Streams on the Greenland Ice Sheet Delineated From Combined Spectral–Shape Information in High-Resolution Satellite Imagery
Abstract
Supraglacial meltwater streams and lakes that form each summer across large expanses of the Greenland Ice Sheet (GrIS) ablation zone have global implications for sea level rise but remain one of the least studied hydrologic systems on Earth. Remote sensing of supraglacial streams is challenging owing to their narrow width (~1-30 m) and proximity to other features having similar visible/near-infrared reflectance (lakes and slush) or shape (dry stream channels, crevasses, and fractures). This letter presents a new automated “spectral-shape” procedure for delineating actively flowing streams in high-resolution satellite imagery, utilizing both spectral and pattern information. First, a modified normalized difference water index adapted for ice ( NDWIice) enhances the spectral contrast between open water and drier snow/ice surfaces. Next, three NDWIice thresholds are used to mask deep-water lakes and discern open water from slush, in concert with a multipoints fast marching method to rejoin resulting stream fragments. Comparison of this procedure with manual digitization for six WorldView-2 images in southwestern Greenland demonstrates its value for detecting actively flowing supraglacial streams, particularly in slushy areas where classification performance dramatically improves (85.2% success) versus simple threshold methods (52.9% and 59.4% success for low and moderate thresholds, respectively). While a simple threshold approach is satisfactory for areas known to be slush free, the procedure outlined here enables comprehensive stream mapping across the GrIS ablation zone, regardless of slush conditions and/or the presence of similarly shaped glaciological features.
Year
DOI
Venue
2013
10.1109/LGRS.2012.2224316
IEEE Geosci. Remote Sensing Lett.
Keywords
Field
DocType
snow,spectral-shape procedure,pattern information,remote sensing,slush conditions,glaciology,spectral information,drier ice surfaces,sea level rise,normalized difference water index (ndwi),lakes,glaciological features,high-resolution satellite imagery,crevasses,worldview-2 images,gris ablation zone,southwestern greenland,manual digitization,greenland ice sheet (gris),dry stream channels,slushy areas,supraglacial stream hydrology,sea level,fracture,actively flowing streams,visible reflectance,hydrological techniques,stream fragments,mathematical morphology,fast marching method,open water,supraglacial meltwater streams,threshold methods,multipoint fast marching method,geophysical image processing,stream mapping,hydrologic systems,worldview-2,drier snow surfaces,modified normalized difference water index,greenland ice sheet ablation zone,spectral-shape information,classification performance,fractures,spectral contrast,deep-water lakes,near-infrared reflectance,accuracy,shape
Geomorphology,Ablation zone,Satellite imagery,Greenland ice sheet,Remote sensing,Meltwater,Cryosphere,Slush,STREAMS,Snow,Mathematics
Journal
Volume
Issue
ISSN
10
4
1545-598X
Citations 
PageRank 
References 
7
0.74
2
Authors
2
Name
Order
Citations
PageRank
Kang Yang17819.31
Laurence C. Smith27411.21