Near-coastal iceberg distributions in East Antarctica, 50-145° E

Abstract

ABSTRACT. A survey of icebergs using satell ite radar images has been made in the seasonal sea-ice zone of East Antarctica in the sector between longitudes 50° and 145° E. These data provide information on the spatial distribution and size statistics of icebergs near the coast in areas not often visited by shipboard observers, and close to their sources at ice shelves and glacier tongues. The icebergs are detected and their dimensions extracted by analysis of the texture properties present in satellite images acquired with ERS-l synthetic aperture radar during the austral winter. The minimum size of iceberg reliably detected and measured is 0.06 km 2 .A significant variation, by up to a factor of two, is found in the area of icebergs close to different sections of the coast, which suggests a characteristic size for different sources. The average value of the length-to-width ratio for icebergs in the whole population shows some variability with size. The probability of finding icebergs is greatest close to the coast, decreasing in general with distance from the coast, such that few icebergs were detected more than 160 km from the coast. In one sector about 85° E, icebergs are found to at least 550 km from the coast, which is consistent with the transport of icebergs northwards in this region by a branch of the westward-heading near-coastal current (East Wind Drift ) which connects with the southern margins of the eastward-heading Antarctic Circumpolar Current.

Calving Fronts of Antarctica: Mapping and Classification

“…The result is a mean detection performance of 64 % for the test site ( Figure 1). The result of the detection performance is very similar to the ones presented by [27] and [22]. Both presented iceberg detection algorithms using thresholding and the sigma-on-mu, respectively, with variable detection performances [22,27].…”

“…The result of the detection performance is very similar to the ones presented by [27] and [22]. Both presented iceberg detection algorithms using thresholding and the sigma-on-mu, respectively, with variable detection performances [22,27]. Our detection performance can be traced back to the application of the enhanced Lee filter, which causes the radar intensity variations in the SAR scene to become smoother and the contrast between homogeneous and heterogeneous areas to become lower.…”

“…The automated detection of surface structures using the RAMP AMM-1 SAR image mosaic is based on an edge detection method (sigma-on-mu) described by Septhon et al [21] and Young et al [22]. The floating ice masses (shelves and tongues) were extracted automatically using the MOA grounding line [23] and the coastline of the RAMP AMM-1 project (http://bprc.osu.edu/rsl/radarsat/data).…”

From ice shelves to icebergs: Classification of calving fronts, iceberg monitoring and drift simulation

“…osu.edu/rsl/radarsat/data/). We applied an edge detection filter based on the mean and the standard deviation of the backscattering coefficients [3]. Additionally, we complemented the automated detection by visual inspection.…”

A semi‐automated line tracing technique for monitoring ice margins in Antarctic images

“…Young et al (1998) have surveyed icebergs in the seasonal sea-ice zone of East Antarctica, using SAR images from the ERS-1 satellite. A semi-automated image analysis technique developed by Williams et al (1999) was used in this survey.…”