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Laser leveling exercises with rotating laser were carried out during N-ICE 2015. The sea-ice and snow surface elevation were computed with reference to the local sea-surface found by drilling at the corners of the laser leveling field.
Total ice and snow thickness was measured with portable electromagnetic instruments (EM31 and EM31SH, Geonics Ltd., Mississauga, Ontario, Canada) mounted on a sledge. The EM31s measure the received secondary electromagnetic field, induced by highly conductive seawater (Kovacs et al., 1991). Conductivity values are calibrated with drill hole measurements and post processed according to Haas et al., 1997. Figure 1 (https://api.npolar.no/dataset/70352512-fed8-4f1d-8b9c-30e6a764f5c2/_file/f5fa353f31a63b4d4167379acc785e73) shows the calibration curves for the two EM instruments used throughout the experiment. In total 101 and 145 calibration drillings were made for EM31SH and EM31, respectively, covering a thickness range from 0.15 m to 4.50 m ice. Analysis of the calibration measurements did not reveal any drift in the fitting curve parameters on the temporal or spatial scales.
The footprint size of the EM31 ranges from 3 m to 5 m, depending on the ice and snow thickness. Accuracy of EM31 measurements is in the range of +-0.1 m for level ice, becoming higher for rough and deformed ice.
On all four Floes, independent (i) and repeated transects (t, tF, tM) with combined EM31 and snow depth measurements were performed.
Repeated transects are considered as repetitions of marked tracks on a weekly basis to observe temporal change, while independent transects are long surveys in different directions from the main ice camp are to cover the spatial variability of the surrounding area.
Quality
Data is provided as CSV textfiles.
The filename contains date in format YYYYMMDD, thereafter unique line number, thereafter either i (independant), t (transect), tF (transect on FYI only), or tM (transect on MYI only).
Variables
- lonres: driftcorrected WGS84 longitude
- latres: driftcorrected WGS84 latitude
- thickres [m]: total thickness
- gpstimeres: time (matlab)
The data set comprises a collection of products showing the sea ice surface topography for the area of Floe 3 ice camp during N-ICE 2015 leg 5 for 24 May 2015. The surface topography is derived using photogrammetry from the series of images acquired by ICE camera setup during a survey flight on 24 May 2015. Data are presented in two resolutions on a regular 2 cm and 5 cm mesh in UTM coordinates and covers the area of about 0.81 km2 (1.7 by 0.6 km). For convenience, three different output formats are used: ascii XYZ table, GeoTiff and generic Socet GXP DTM.
- NICEfloe3_005.dtm (.dth .dtp) Socet GXP DTM product on 5 cm mesh
- NICEfloe3_002.dtm (.dth .dtp) Socet GXP DTM product on 2 cm mesh
- NICEfloe3_005.tif GeoTiff with 5 cm DTM
- NICEfloe3_002.tif GeoTiff with 2 cm DTM
- NICEfloe3_005_XYZ.txt ASCII XYZ (East, North, elevation) DTM on 5 cm mesh
- NICEfloe3_002_XYZ.txt ASCII XYZ (East, North, elevation) DTM on 2 cm mesh
- UTM_coordinates_for_ locations_on_floe3.xlsx List of some of study sites/objects on Floe3 with coordinates including the rectangular area with R/V Lance.
- NICEfloe3_orthophoto.tif (https://api.npolar.no/dataset/c16918e8-7f24-4131-9f02-7bcb690b594e/_file/NICEfloe3_orthophoto.tif) Orthophoto of the reconstructed area
- NICEfloe3_elevationmap.tif Surface elevation map in tiff format