This dataset contains sea ice surface brightness temperatures using a portable passive-microwave radiometer operating at 36Ghz-H,V mounted to the undercarriage of a Squirrel helicopter during SIPEX 2, 2012. This radiometer is the same sensor as satellite passive-microwave radiometer AMSR-E and AMSR2. Our passive-microwave radiometer is launched on the same helicopter as Jan Lieser's (RAPPAL), so please see the "SIPEX-2 RAPPLS Surveys (Radar, Aerial Photography, Pyrometer, and Laser Scanning system)" metadata file for details of the aircraft. The RAPPLS dataset also contains track (GPS position) and altitude data, which can be used in conjunction with this dataset. The CSV files in this dataset are the raw files as output by the sensor. These raw data files show only the relevant parameters (time and brightness temperatures).

This dataset contains data relating to an experimental method in which sea-ice samples were measured in an S-band microwave waveguide. This was conducted as a part of the 2012 SIPEX 2 (Sea Ice Physics and Ecosystems EXperiment) marine science voyage. A specially designed waveguide apparatus was connected to an Agilent FieldFox Portable Network Analyzer. Small parallelopipeds (7 cm X 3 cm X 1.9 cm) of sea ice were cut with a hand saw in a specially designed jig which holds an initially cylindrical core. The samples were placed at the end of the waveguide, configured to measure the vertical component of the effective complex permittivity tensor, and microwaves of frequency 2.9 GHz were sent down the tube. The samples were sized precisely to fit snugly in the end of the waveguide in order to minimize spurious reflections. The FieldFox recorded the coefficients of the scattering matrix, from which the complex permittivity can be computed. Sample temperature was taken both before and immediately after insertion into the waveguide. In order to assess the presence of off-vertical components of the electromagnetic field and how they may affect the measurements, a second sample was prepared with an orthogonal orientation, adjacent to the first sample. The same microwave measurements were taken on the second sample, to be later correlated with those from the first sample. The samples were stored in the freezer for later crystallographic analysis, and subsequently melted for salinity measurements. Prior to melting the samples were measured using callipers to determine their dimensions precisely. Samples were measured along each face at their minimum and maximum point for their width in the direction of propagation. In most cases samples were measured in all dimensions for better error analysis. A thin vertical section, approximately 5mm thick, was taken from each microwave sample stored for analysis. These sections were placed between a pair of cross polarized plates and photographed. Photos of the crystallography cores can be found in the crystallography folder, in a sub folder titled microwave. Each photo also contains a tag indicating the core number, site taken, date, as well as a V or an H indicating whether the sample was used for measurement of the vertical (V) or off-vertical (H) response. The scattering parameters recorded by the Field Fox can be found in the Data folder. Each file is named according to the microwave core measurement it represents and whether the measurement was of the vertical (V) or off-vertical (H) response. Each contains a standard S11 scattering parameter, stored as a comma separated value (CSV) file. Raw data can be found in the raw folder, and data that has been processed for ease of Matlab import can be found in the Reformatted_for_matlab folder. This processing involves taking output data that by default has four entries in a single column vector and remapping the data to create a four column matrix, each with a single entry. Recorded values for each microwave sample can be found in the Master_Core_List.xls Excel spreadsheet, within the Microwave worksheet. This worksheet was generated directly from notebook data, and contains the date, core number, depth of interface between the two collected samples, the minimum, maximum, and average thickness along the axis of propagation, The recorded temperatures from before and after measurement, the salinity, and calculated brine volume fraction. Finally, the worksheet contains notes, and a column to indicate whether we believe this data is somehow bad. Measurement information for thicknesses along other axis than that of propagation can be found in notes, but this data may at some stage be incorporated into a separate column. Please see the notes section for reasons why a data point was determined invalid. Typically this was due to the corresponding sample breaking while cutting into the parallelepiped shape. Scans of the original notebooks containing measured salinity values, thicknesses, and temperatures from which the Permeability worksheet were created are provided in the notebooks directory.

This dataset relates to long-term change and variability in annual timings of sea ice advance, retreat and resultant ice season duration in East Antarctica derived from the satellite passive-microwave time series dating back to Nimbus 7. These were calculated from satellite-derived ice concentration data for the period 1979/80 to 2009/10. The dataset includes more detailed analysis of change and variability in sea ice conditions along meridional transects i.e., 110 degrees E and 140 degrees E relating to sea ice concentration and extent, and along 90 deg E, 100 deg E, 110 deg E and 140 deg E for trends in sea ice concentration for the period 1979-2010. Also included are monthly sea-surface temperature (SST) trends mapped north of the East Antarctic sea-ice zone for the period 1982-2010. The SST data are from the Reynolds and Smith OLv2 dataset. These data form the basis of the publication: Massom, R.A., P. Reid, S. Stammerjohn, B. Raymond, A. Fraser and S. Ushio. 2013. Change and variability in East Antarctic sea ice seasonality, 1979/80-2009/10. PloS ONE, 8(5), e64756, doi:10.1371/journal.pone.0064756