This indicator is no longer maintained, and is considered OBSOLETE. INDICATOR DEFINITION Regular measurements of the thickness of the fast ice, and of the snow cover that forms on it, are made through drilled holes at several sites near both Mawson and Davis. TYPE OF INDICATOR There are three types of indicators used in this report: 1.Describes the CONDITION of important elements of a system; 2.Show the extent of the major PRESSURES exerted on a system; 3.Determine RESPONSES to either condition or changes in the condition of a system. This indicator is one of: CONDITION RATIONALE FOR INDICATOR SELECTION Each season around the end of March, the ocean surface around Antarctica freezes to form sea ice. Close to the coast in some regions (e.g. near Mawson and Davis stations) this ice remains fastened to the land throughout the winter and is called fast ice. The thickness and growth rate of fast ice are determined purely by energy exchanges at the air-ice and ice-water interfaces. This contrasts with moving pack ice where deformational processes of rafting and ridging also determine the ice thickness. The maximum thickness that the fast ice reaches, and the date on which it reaches that maximum, represent an integration of the atmospheric and oceanic conditions. Changes in ice thickness represent changes in either oceanic or atmospheric heat transfer. Thicker fast ice reflects either a decrease in air temperature or decreasing oceanic heat flux. These effects can be extrapolated to encompass large-scale ocean-atmosphere processes and potentially, global climate change. DESIGN AND STRATEGY FOR INDICATOR MONITORING PROGRAM Spatial Scale: At sites near Australian Antarctic continental stations: Davis; Mawson. Frequency: at least weekly, reported annually Measurement Technique: Tape measurements through freshly drilled 5 cm diameter holes in the ice at marked sites. RESEARCH ISSUES To more effectively analyse the changes in Antarctic fast ice a detailed long-term dataset of sea ice conditions needs to be established. This would provide a baseline for future comparisons and contribute important data for climate modelling and aid the detection of changes that may occur due to climate or environmental change. LINKS TO OTHER INDICATORS SOE Indicator 1 - Monthly mean air temperatures at Australian Antarctic stations SOE Indicator 40 - Average sea surface temperatures in latitude bands 40-50oS, 50-60oS, 60oS-continent SOE Indicator 41 - Average sea surface salinity in latitude bands: 40-50oS, 50-60oS, 60oS-continent SOE Indicator 42 - Antarctic sea ice extent and concentration The fast ice data are also available as a direct download via the url given below. The data are in word documents, and are divided up by year and site (there are three sites (a,b,c) at each station). Snow thickness data have also been included. A pdf document detailing how the observations are collected is also available for download.

This dataset contains 102 depth measurements of the water column in Long and Tryne fjords, which are in the northern Vestfold Hills, Prydz Bay, Antarctica. Sea ice thickness and snow thickness were recorded simultaneously. The motivation for this project has been to yield a description of the pupping and moulting habitat of Weddell seals. This information will assist the interpretation of 25+ years of data on seal distribution within that area. Our data were collected between 7th and 13th December 1999. The measurement sites were chosen according to geographical features; their exact location was determined by GPS with an accuracy of about 25m. At each site a 5cm diameter hole was drilled through the sea ice and a weighted measurement tape was lowered through the ice-hole to the bottom. Water depths were measured to the nearest centimetre; ice and snow thicknesses were measured to the nearest millimetre. A minimum depth of less than 3m was found in a narrow channel between small islands immediately west of Shirokaya Bay. The maximum depth of the water column was 222m in the middle basin of Long Fjord. The tidal range for the measured days was less than 0.5m, with tidal corrections applied to the raw data. Water samples were taken in Breid Basin and the middle basin of Long Fjord. These and water samples taken in Snezhnyy Bay [pers. comm. J. Laybourn-Parry, 1999] show aerobic and relatively fresh water for all upper basins. This indicates that even the far basins of both fjords are well mixed despite the drainage of large volumes meltwater from the Antarctic plateau into the fjords. See related URL for data and a spatial summary of the data. See Entry: long_tryne_bathy for an interpolation of bathymetry made using the Topogrid command within the ArcInfo GIS software, version 8.0.2. Coastline and spot height (heights above sea level) data, extracted from the Australian Antarctic Data Centre's Vestfold Hills topographic GIS dataset (see Entry: vest_hills_gis), was also used as input data to optimise the interpolation close to the coastline. The fields in this dataset are: day weighpoint lat(dd) long(dd) ice (cm) freeboard(cm) snow(cm) depth(m)

Very little information is available on the geomorphology of areas surrounding Australian Antarctic stations. This type of information is generally collected during geological surveys. This metadata record gathers a range of descriptive geomorphological information of various nature: -Habitat surveys were conducted in the season 2002-2003 in the Windmill Islands in parallel with bird nest mapping (reported in metadata record BIRDSCASEY0203) in order to study selection of nest sites by a range of species. Habitat was described in the survey sites searched for bird nests following various methods (described in BIRDSCASEY0203). Information is stored as GIS files (Arcview 3.2) -polygon shapefile gathering all the geomorphological units. -line shapefile describing habitat along transects used for searching bird nests -polygon shapefile describing habitat in small 25*25m quadrats used for searching bird nests -A collection of 1309 digital photos showing the sites searched for bird nests indexed by grid site number. Plus another set of 194 photos showing region of the Windmill Islands or bird nests more in detail -A set of Digital Elevation Models (DEM) covering the entire Windmill Islands area generated separately for 18 regions. -200m*200m grid created from the coverage of ice-free areas (Aerial photography 93-94) providing site numbers for the photographic database -A series of Black and White aerial Photos (500 m, Zeiss, 1994) scanned at high resolution for the purpose of substrate study. See the word document in the file download for more information. This work has been completed as part of ASAC project 1219 (ASAC_1219). The fields in this dataset are: Date Boulderbig Bouldsmall Baresubst Morsed Scree Snowcover Permice Slope Aspect Photonumber Sitedotid Comments

The Thala Valley Tip Site GIS dataset mapped from January 2001 aerial photography. The dataset includes watercourse, waterhole, breakline, spot height, contour, embankment, rock, sea ice, snow, tide crack and contaminated site features.

Very little information is known about the distribution and abundance of snow petrels at the regional scale. This dataset contains locations of bird nests, mostly snow petrels, mapped in the Windmill Islands during the 2002-2003 season. Location of nests were recorded with handheld GPS receivers connected to a pocket PC and stored as a shapefile using Arcpad (ESRI software). Descriptive information relating to each bird nest was recorded and a detailed description of data fields is provided in the detailed description of the shapefiles. Two observers conducted the surveys using distinct methodologies, Frederique Olivier (FO) and Drew Lee (DL). Three separate nest location files (ArcView point shapefiles) were produced and correspond to each of the survey methodologies used. Methodology 1 was the use of 200*200 m grid squares in which exhaustive searches were conducted (FO). Methodology 2 was the use of 2 transects within each the 200*200 m grid squares; methodology 3 was the use of 4 small quadrats (ca 25 m) located within the 200*200m grid squares (DL). Nests mapped in a non-systematic manner (not following a specific methodology) are clearly identified within each dataset. Datasets were kept separate due to the uncertainties caused by GPS errors (the same nest may have different locations due to GPS error). Three separate shapefiles describe survey methodologies: - one polygon shapefile locates the 200*200 grid sites searched systematically (FO) - one polygon shapefile locates the small quadrats (DL) - one line shapefile locates line transects (DL) Spatial characteristics, date of survey, search effort, number of nests found and other parameters are recorded for the grid sites, transect and quadrats. See the word document in the file download for more information. This work has been completed as part of ASAC project 1219 (ASAC_1219). The fields in this dataset are: Species Activity Type Entrances Slope Remnants Latitude Longitude Date Snow Eggchick Cavitysize Cavitydepth Distnn Substrate Comments SitedotID Aspect Firstfred Systematic/Edge/Incidental RecordCode The full dataset, including a word document providing further information about the dataset, is publicly available for download from the provided URL. Also available for download from another URL is polygon data representing flying bird nesting areas. The polygon data was derived from the flying bird nest locations by the Australian Antarctic Data Centre for displaying on maps.