Geomorphological mapping of ice-free areas using polarimetric RADARSAT-2 data on Fildes Peninsula and Ardley Island, Antarctica

Abstract

International audienceSatellite-borne Synthetic Aperture Radar (SAR) has been used for characterizing and mapping in two relevant ice-free areas in the South Shetland Islands. The objective has been to identify and characterize land surface covers that mainly include periglacial and glacial landforms, using fully polarimetric SAR C band RADARSAT-2 data, on Fildes Peninsula that forms part of King George Island, and Ardley Island. Polarimetric parameters obtained from the SAR data, a selection of field based training and validation sites and a supervised classification approach, using the support vector machine were chosen to determine the spatial distribution of the different landforms. Eight periglacial and glacial landforms were characterized according to their scattering mechanisms using a set of 48 polarimetric parameters. The mapping of the most representative surface covers included colluvial deposits, stone fields and pavements, patterned grounds, glacial till and rock outcrops, lakes and glacier ice. The overall accuracy of the results was estimated at 81%, a significant value when mapping areas that are within isolated regions where access is limited. Periglacial surface covers such as stone fields and pavements occupy 25% and patterned grounds over 20% of the ice-free areas. These are results that form the basis for an extensive monitoring of the ice-free areas throughout the northern Antarctic Peninsula region

Evaluation of machine learning algorithms to classify and map landforms in Antarctica

“…The low uncertainty of the SVM, in turn, was probably associated with the efficient optimization of its hyperparameters in caret. To the best of our knowledge, only SVM among the ML models tested in this work had been used for classifying geomorphology in the Antarctic Peninsula region (Schmid et al, 2012, 2017). Applying the SVM in Vega Island, we obtained a considerably better accuracy than the above authors, who used this algorithm to classify geomorphology in islands of Maritime Antarctica.…”

“…Such landforms encompass patterned ground (Luoto & Hjort, 2005), rock glaciers (Brenning et al, 2007), loess (Zhao et al, 2017), glacial deposits (Zhang et al, 2019), floodplains (Woznicki et al, 2019), alluvial fans (Pipaud & Lehmkuhl, 2017), bedrock outcrops (Scarpone et al, 2017), seamounts (Lawson et al, 2017) and even Martian craters (Urbach & Stepinski, 2009). However, in Antarctica, digital geomorphological mappings are very scarce, with only a few records of ML approaches in the Antarctic Peninsula and surrounding islands (Schmid et al, 2012(Schmid et al, , 2017.…”

Abiotic factors influencing soil microbial activity in the northern Antarctic Peninsula region

“…Sampling was J o u r n a l P r e -p r o o f carried out within areas representing different geomorphological features and surface covers. On DI and FP sampling was constrained to areas where soil forming processes was minimal such as on weathered bedrock with vegetation cover and fine volcanic deposits where bare soil and sparse vegetation was present (Schmid et al, 2017). In contrast, at CP, where there is an abundance of vegetation, samples were taken in areas that had a high vegetation cover and soil forming processes were more advanced.…”

Advances in Mapping Ice-Free Surfaces within the Northern Antarctic Peninsula Region using Polarimetric Radarsat-2 Data

“…Remote sensing techniques offer a great potential to identify relief and landscape features, as well as detect changes in areas where access is difficult and little or no data are available [3]. Synthetic Aperture Radar (SAR) sensors are useful for determining physical properties of terrestrial land covers such as structure and roughness [4]. Furthermore, in environments encountered in the Antarctic Peninsula region, using SAR data is of advantage because microwaves function in all-weather conditions.…”

“…Considering the sensor characteristics and spatial resolution, preliminary satisfactory results were obtained to map complex geomorphological features such as periglacial landforms. This was initially tested for the area of Fildes Peninsula where satisfactory results were obtained as shown in previous work [4]. However, for the wider area the ground information and other ancillary sources are considered limited, at this moment, to carry out a robust validation.…”