Snow: IOP
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Snow: IOP |
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| Between
31 March and 11 May 1998, extensive measurements of the physical
characteristics, and the distribution of these characteristics, were made
in and about the SHEBA camp. A series of stations on lines radiating 2 to
20 km from the ship were occupied, and at each station a set of
measurements was made. The standard protocol at each station was to:
1. lay out a 100-m tape across the local ice and snow structures, 2. Probe the snow depth every 0.5 m along the line. 3. Use a rotating laser and a self-reading leveling rod to profile the snow surface along the line at the same interval, 4. Dig snow pits at six locations (0, 20, 40, 60, 80, and 100 m) along the line, 5. Record the thickness of each layer and cross-correlate the layer to those in other pits on the line and at other stations, 6. Measure the hardness and density of each layer using a 100-cc cutter and digital balance, 7. Use a Federal coring sampler to obtain full snow-depth cores of the snow at 10 locations along the line to measure bulk density and snow-water equivalent (SWE). At many stations, the temperature of the snow-ice interface was measured using thin carbon-fiber probes that were pushed down through the snow to the ice surface. In addition snow/ice interface temperatures were monitored continuously at 30 sites. These measurements were made along the 100-m line, usually at 0.5-m spacing coincident with the depth measurements. Thermal conductivity measurements were also made on selected layers, but are not reported here as they are still being analyzed. Snow Depth: In all, over 21,000 measurements of snow depth were made at all stations. These are collected together in the file SNWDEPTH and the data for a histogram of the depth distribution is given in the file SNOWHIST. Snow Profiles: Each profile was referenced to the sea surface by drilling a hole through the ice and measuring the elevation at one spot with reference to that surface. Elevations are generally accurate to ±0.03 m. For each station, the snow surface and ice surface elevation are listed. The horizontal coordinate system starts at 0 and increments 0.5 m to 100 m unless otherwise noted. The file is called PROF100M. Snow depths for each station can be calculated by subtracting the base elevation from the surface. |
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Map of snow measurement sites. |
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Snow water equivalent (SWE) as a function of depth. |
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| Snow Stratigraphy: There were basically nine layers in the snow pack. They were arbitrarily labeled: r, c, m, n, n-parting, o, p, q, and snow ice (at the base of the pack). This figure shows what the typical stratigraphy was like and provides general information on the density and other characteristics of each layer. The file SNOWPIT.TXT lists all the data, by layer. | |
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| Snow Water Equivalent: Results from coring the snow at stations using a Federal Sampler are listed in the table SWEDATA. A regression of the SWE as a function of the snow depth shows that the SWE can reliably be predicted from the depth. To illustrate the spatial variability of the snow density and SWE, we have plotted these variables as a function of the station. | |
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