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EARTH SCIENCE > OCEANS > SEA ICE > ICE DEPTH/THICKNESS

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  • Depth to sea floor and sea ice thickness data measured at various locations around the Vestfold Hills, Davis station, East Antarctica, during the 2018-19 austral summer. Depth to sea floor and sea ice thickness measures in meters obtained using a weighted tape measure deployed through a hole (5 cm) drilled in the sea ice. Sea ice thickness was determined by snagging the weight on the underside edge of the ice hole as the tape measure was retreived.

  • Observations of the sea ice cover at Wilkes base in Autumn-Winter 1963. Includes water temperature, air temperature, wind speed and direction, cloud cover, relative humidity, and general notes. These documents have been archived at the Australian Antarctic Division.

  • We observed total thickness (snow thickness + ice thickness) of sea-ice floes along 100m transects using an electromagnetic (EM) sensor. The data were read from the EM and written by hand into a log book as we moved along the transect. They were then transferred into an Excel spreadsheet. The parameters included are: - distance along transect - conductivity (vertical) - conductivity (horizontal) - total thickness (derived from vertical and horizontal conductivities)

  • This dataset contains records of ice thickness and snow thickness from Casey, Antarctica. Measurements were attempted on a weekly basis and were recorded between 1979 and 1992. The observations are not continuous however. The dataset is available via the provided URL. This data were also collected as part of ASAC projects 189 and 741. The Casey fast ice thickness data are no longer being collected.

  • This dataset contains records of ice thickness and snow thickness from Mawson, Antarctica. Measurements were attempted on a weekly basis and have been recorded since 1954 and are ongoing, although this record only contains data up until the end of 1989. The observations are not continuous however. The dataset is available via the provided URL. These data were also collected as part of ASAC projects 189 and 741. Logbooks(s): Glaciology Sea Ice Log, Mawson 1969 Glaciology Mawson Sea Ice Logs, 1995-2000

  • Observations of the sea ice near Mawson were carried out in 1980, concentrating on the thickness of the ice at several points, and the accumulation and ablation of snow/ice cover on the ice. The ablation measurements were carried out by laying 23 ablation stakes out in two fields - a set of eight stakes in a straight line, and a set of 15 in a triangle. Results from both sets of observations were recorded in a log book, currently archived at the Australian Antarctic Division.

  • This dataset contains records of ice thickness and snow thickness from Davis Antarctica. Measurements were attempted on a weekly basis and have been recorded since 1957 and are ongoing, although data have only been archived here until 2002. The observations are not continuous however. The dataset is available via the provided URL. This data were also collected as part of ASAC projects 189 and 741. Logbook(s): Glaciology Davis Sea Ice Logs 1992-1999

  • Metadata record for data from ASAC Project 2500 See the link below for public details on this project. Public Weekly fast-ice and snow thicknesses from an ongoing long-term time-series together with meteorological data will be used to analyse ice-atmosphere interactions. Interannual changes will be related to climate effects. Various sites at each location will be sampled to resolve the influence of oceanic forcing on the fast-ice growth. Project objectives: Landfast sea ice (fast ice) forms on the near-coastal ocean off each of the three Australian Antarctic stations each autumn. At Mawson and Davis stations this ice cover is generally stable, increasing in thickness throughout the winter to reach its maximum thickness in October or November before decaying and eventually breaking out in late spring or summer [Heil and Allison, 2002a]. At Casey, the third Australian station, the fast-ice cover is very unstable and not suitable for the study proposed here. The fast ice at the proposed measuring sites is stationary all through the austral winter. There is no contribution due to mechanical processes (rafting or ridging) on the thickness evolution of the fast ice at the measuring sites [Heil, 2001]. Its growth and decay, and the annual maximum thickness depend primarily on thermodynamic processes [Heil et al., 1996], which are forced by energy and moisture exchanges at the atmosphere-ice interface, the thickness of the snow cover, and the thermal energy supplied to the underside of the ice from the ocean. Starting in the mid 1950s measurements of the fast-ice thickness and snow cover are available for individual years at Mawson and Davis stations. After quality control the combined record for Mawson includes data from 27 seasons; the Davis record includes 20 seasons [Heil and Allison, 2002a]. However, significant gaps exist in these historic records. The scientific value of a continuous record of fast-ice thickness as a climatic indicator has been recognised and as a consequence the fast-ice and snow measurements at Davis and Mawson have been accepted into the State of the Environment (SOE) reporting scheme by the Australian Antarctic Division. Data from ANARE fast-ice measurements have been included in scientific research (e.g., Mellor [1960], Allison [1981], Heil et al. [1996], or Heil and Allison [2002a]). For example, Heil et al. [1996] designed an inverse 1-dimensional thermodynamic sea-ice model and used historic fast-ice data from Mawson together with meteorological observations to derive the seasonal and interannual variability of the oceanic heat flux at the underside of the fast ice. They showed that the interannual variability identified from the fast-ice data was in agreement with changes in the water-mass properties observed upstream of the fast-ice site. Using the historic data together with data from ongoing measurements this project aims to quantify the local-scale interactions between atmosphere and fast ice, to derive the relative impact of oceanic forcing on the fast-ice evolution, to estimate the small-scale spatial variability of the fast-ice growth, and to explore the connection between fast-ice changes and climate change. In particular we aim: - to extend previous analysis from records of fast-ice observations for Mawson and Davis stations; - to exactly determine the growth-melt cycle of East Antarctic fast ice and its modifications due to changing environmental conditions; - to derive the statistical variability of the fast-ice evolution relative to atmospheric and oceanic forcing; - to evaluate the suitability of fast ice as indicator of changes in the Antarctic environment; - to determine the spatial coherence of fast-ice properties. Contribution of this research to achieving the relevant milestones contained in the Strategic Plan: - Contributions to Key Scientific Output 3: This research aims to derive an assessment of the links between fast-ice variability and Southern Hemisphere environmental conditions from in-situ observations. The annual maximum ice thickness, and the date at which this maximum thickness is reached, reflect the integrated conditions of the local atmospheric and oceanic parameters [Heil, in prep.]. The fast-ice measurements together with concurrent meteorological (and oceanic) observations will allow us to study the direct links of variability in the sea-ice thermodynamics to changes in the Southern Hemisphere atmospheric conditions ("weather" in KSO 3.1). This knowledge will aid our understanding of the interannual and long-term variability of the drifting sea ice, as it will allow us to separate thermodynamic effects from dynamic effects [Heil et al., 1998]. Research outcomes from this study will aid the parameterisation of thermodynamic sea-ice processes in coupled climate models, and will provide an outlook towards statistical parameterisation of fast-ice characteristics within numerical models. - Contributions to Key Scientific Output 4: Using historic data and ongoing measurements this project seeks to build an accurate and ongoing record of measurements of fast-ice and snow properties for the monitoring and detection of change in Antarctic and Southern Ocean climate. Changes identified in the fast-ice thickness or in the occurrence of the annual maximum ice thickness are due to changes in either oceanic or atmospheric heat and/or moisture transfer. Using fast-ice measurements from locations around the Antarctic continent in combination with large-scale atmospheric (and oceanic) data the external impact on the sea ice can be extrapolated. Historic climatologies of interannual variability will be updated and extended. These climatologies will be available to expedition operations, scientific research, etc. Assessment basis: * Completion of field work/primary scientific activity: The requirements of data collection for this project are in line with indicator No. 43 "Fast ice thickness at Davis and Mawson" of the State of the Environment (SOE) reporting scheme. Weekly measurements of fast-ice and snow thicknesses are required for the SOE scheme as well as for this project. Additional data on the freeboard of the ice are easily and quickly obtained during the standard measurements [Heil and Allison, 2002b]. It is worthwhile to emphasise the requirement of a long-term commitment for the field measurements in order to obtain meaningful and statistically significant records of fast-ice observations. * Completion of analysis: The evaluation of individual growth-decay seasons will be undertaken once all fast-ice data as well as all required auxiliary data (mainly meteorological measurements) are available to the CI. Where available, opportunistic oceanographic data will be acquired as part of related research projects. Analysis to assess the interaction between fast ice, atmosphere and ocean will be carried out for each growth-decay season. This will include numerical modelling of the thermodynamic processes in fast-ice growth and decay. For years, when measurements of all external forcing fields (oceanic and atmospheric) have been collected, the parameterisations of the thermodynamic model can be evaluated by comparing the model results with the observed fast-ice thickness and growth rates. Following Heil et al. [1996] the thermodynamic model can be reconfigured for use in the inverse mode, using atmospheric and fast-ice data to calculate the oceanic heat flux at the underside of the ice. Long-term records of changes in the oceanic heat flux are not available and this inverse method (driven with data derived from meteorological and fast-ice measurements) will be able to contribute to our understanding of coastal oceanography by using several measuring sites within a small area. Analysis of the interannual variability of the fast ice and its response to changing environmental conditions will be carried out on the long-term data record. The data will be analysed for long-term signals, and will be evaluated for their statistical significance. * Publication of results: Scientific findings will be written up and submitted for publication as they arise. Publications in high-impact international journals are expected about every 2 years.

  • Four ice monitoring stations were set up at Davis in 1993 (a fifth station was added after the first two months), with regular recordings of ice depth, snow cover and ablation made for each station by taking a sea ice core. Observations of the general condition of the drilled cores were also recorded. Observations were made at irregular intervals (roughly every 1-2 weeks). The observations for each individual day are listed, along with a summary table. These records are stored as handwritten files, and are archived at the Australian Antarctic Division.

  • This dataset contains in situ measurements of ice thickness, snow thickness, and freeboard along transects on the ice-station floes from the SIPEX2012. Ice cores were collected and snow pits were measured at the 0m, 50m and 100m mark along each transect, where possible. Ice temperature measurements are taken in the field as soon as the ice core sections have been recovered from the core hole. Additionally, ice cores were taken for density analysis at a few of the ice-core sites for independent verification of ice density. In addition, electromagnetic [EM] induction measurements of total ice and snow thickness were conducted along the transect where possible. Ice core were transferred -20oC freezer for thin-section analysis for sea-ice stratigraphy and crystallography. The cores are then cut up into suitable short sections, generally about 5cm long, to be melted for analysis of salinity and stable oxygen isotopes. The latter will occur after the end of this cruise. There is a data file for each ice station, containing a spreadsheet with the data. The spreadsheet contains information about how to interpret the data. Also included are the scanned field notes containing the hand-written (raw) data collected in the field. Among many, many volunteers, whose help is gratefully acknowledged here, the following persons were involved in data collection along the transect: Mr Olivier Lecomte, Univ Catholique, Louvain-la-Neuve, Belgium, Member of observation team, olivier.lecomte@uclouvain.be Dr T. Toyota, Inst Low Temp Science, Japan, Member of observation team, toyota@lowtem.hokudai.ac.jp Dr A. Giles, ACE CRC, Member of observation team, barry.giles@utas.edu.au Dr T. Tamura, NIPR, Japan, Member of EM observation team; tamura.takeshi@nipr.ac.jp Mr K. Nakata, EES, Japan, Member of EM observation team; kazuki-nakata@ees.hokudai.ac.jp Data were collected on the following dates: Ice Station 2: 27 - 28 September 2012 Ice Station 3: 03 - 04 October 2012 Ice Station 4: 06 - 08 October 2012 Ice Station 6: 13 - 14 October 2012 Ice Station 7: 19 - 23 October 2012 Ice Station 8: 29 October - 04 November 2012