Archive of the PASATA (PASsive Acoustic Tracking of Antarctic marine mammals) field documentation

Recordings from the PerenniAL Acoustic Observatory in the Antarctic ocean (PALAOA) show seasonal acoustic presence of 4 Antarctic ice-breeding seal species (Ross seal, Ommatophoca rossii, Weddell seal, Leptonychotes weddellii, crabeater, Lobodon carcinophaga, and leopard seal, Hydrurga leptonyx). Apart from Weddell seals, inhabiting the fast-ice in Atka Bay, the other three (pack-ice) species however have to date never (Ross and leopard seal) or only very rarely (crabeater seals) been sighted in the Atka Bay region. The aim of the PASATA project is twofold: the large passive acoustic hydrophone array (hereafter referred to as large array) aims to localize calling pack-ice pinniped species to obtain information on their location and hence the ice habitat they occupy. This large array consists of four autonomous passive acoustic recorders with a hydrophone sensor deployed through a drilled hole in the sea ice. The PASATA recordings are time-stamped and can therefore be coupled to the PALAOA recordings so that the hydrophone array spans the bay almost entirely from east to west. The second, smaller hydrophone array (hereafter referred to as small array), also consists of four autonomous passive acoustic recorders with hydrophone sensors deployed through drilled holes in the sea ice. The smaller array was deployed within a Weddell seal breeding colony, located further south in the bay, just off the ice shelf. Male Weddell seals are thought to defend underwater territories around or near tide cracks and breathing holes used by females. Vocal activity increases strongly during the breeding season and vocalizations are thought to be used underwater by males for the purpose of territorial defense and advertisement. With the smaller hydrophone array we aim to investigate underwater behaviour of vocalizing male and female Weddell seals to provide further information on underwater movement patterns in relation to the location of tide cracks and breathing holes. As a pilot project, one on-ice and three underwater camera systems have been deployed near breathing holes to obtain additional visual information on Weddell seal behavioural activity. Upon each visit in the breeding colony, a census of colony composition on the ice (number of animals, sex, presence of dependent pups, presence and severity of injuries-indicative of competition intensity) as well as GPS readings of breathing holes and positions of hauled out Weddell seals are taken.

Database of GPS data collected by surveys on seismic and volcanic areas of Sicily (Italy) from 1994 to 2013

This is a 20-year long database of GPS data collected by geodetic surveys carried out over the seismically and volcanically active eastern Sicily, for a total of more than 6300 measurements. Data have been convertedi nto the international ASCII compressed RINEX standard in order to be imported and processed by any GPS analysis software. Database is provided with an explorer software for navigating into the dataset by spatial (GIS) and temporal queries.

Snow and ice surfaces on King George Island (Antarctic Peninsula) with high-resolution TerraSAR-X time series, with links to shapfiles and GeoTIFFs

Changes of glaciers and snow cover in polar regions affect a wide range of physical and ecosystem processes on land and in the adjacent marine environment. In this study, we investigate the potential of 11-day repeat high-resolution satellite image time series from the TerraSAR-X mission to derive glaciological and hydrological parameters on King George Island, Antarctica during the period Oct/25/2010 to Apr/19/2011. The spatial pattern and temporal evolution of snow cover extent on ice-free areas can be monitored using multi-temporal coherence images. SAR coherence is used to map glacier extent of land terminating glaciers with an average accuracy of 25 m. Multi-temporal SAR color composites identify the position of the late summer snow line at about 220 m above sea level. Glacier surface velocities are obtained from intensity feature-tracking. Surface velocities near the calving front of Fourcade Glacier were up to 1.8 ± 0.01 m/d. Using an intercept theorem based on fundamental geometric principles together with differential GPS field measurements, the ice discharge of Fourcade Glacier was estimated to 20700 ± 5500 m**3/d (corresponding to ~19 ± 5 kt/d). The rapidly changing surface conditions on King George Island and the lack of high-resolution digital elevation models for the region remain restrictions for the applicability of SAR data and the precision of derived products.