SnowMeasurements

=Snow= We took a 2 m snow core close to camp, next to the location of a 1.4 m snowpit, in which we measured temperature and density (density only in the top 45 cm). We also took a 5 m core close to the 2 m core.



Temperature profile
After an hour after we dug the snowpit to 70 cm, we took the first temperature measurements. We deepened the pit right after the measurements, but started measuring the temperatures about 4 hours later - which might have led to warming of the pit wall, so we only measured the temperature at the bottom of the pit (133 cm).


 * Table 1:** Snow temperatures in a pit close to camp (at location of 2 m core).


 * ~ depth [cm] ||~ T [degrees C] ||
 * 0 || -14.7 ||
 * 5 || -14.6 ||
 * 10 || -15.2 ||
 * 20 || -15.8 ||
 * 30 || -16.6 ||
 * 40 || -17.4 ||
 * 50 || -18.2 ||
 * 60 || -18.7 ||
 * 70 || -18.1 ||
 * 133 || -22.4 ||



Density profile

 * Table 2:** Density profile in a pit close to camp (at location of 2 m snow core). The depth indication is for the lower boundary of the Taylor-LaChapelle density tool.


 * ~ depth [cm] ||~ density [kg/m^3] ||
 * 5 || 460 ||
 * 7.5 || 380 ||
 * 10 || 390 ||
 * 13 || 390 ||
 * 16 || 320 (mostly hoar crystals) ||
 * 19 || 350 ||
 * 22.5 || 490 ||
 * 25.5 || 400 ||
 * 29 || 430/470 ||
 * 33.5 || 400 ||
 * 37.5 || 400 ||
 * 41.5 || 440 ||
 * 44.5 || 410 ||



Near-infrared and translucent measurements
The very hard snow made measurements a challenge. Profiles could be prepared by drilling holes for the vertical guides of NIRTran at the exact distances. The sidewall- and front-walls were sawed (the "Stanley-saw" with fine-toothed points was best). Coring additional holes before sawing made sawing much easier. The front-wall was prepared using the sawing tool, the vertical guides defined the thickness. First, the front wall was lit by NIR lamps (Figure 6(a)) and then the part behind the wall was excavated and the translucent photograph was made (Figure 6(b)). The pits were very bright (compared to Davos conditions). To prevent too much light from the sides, the ski-doo cover was used to cover the surface of the pit (profile 002).



The snow profile for 002 is in Table 3 and Table 4.


 * Table 3:** Snow profile NIRTran002. Classification and symbols IACS 2009.


 * ~ depth [cm] ||~ hardness ||~ grain size (mm) ||~ grain shape ||
 * hline 0 || P-K || 0.1 || RG ||
 * 4 || K || 0.05 || RG ||
 * 4.5 || K || 0.15 || RG ||
 * 6 || 1F-P || 0.8 || RGfc ||
 * 21 || K-I || 1(4) || MFpc ||
 * 21.5 || K || 1-4 || MFpc ||
 * 28 || K || 1-4 || FCpc ||
 * 38 ||  ||   ||


 * Table 4:** Density profile for NIRTran 002.


 * ~ depth [cm] ||~ density [kg/m^3] ||
 * 0-4 || 410 ||
 * 10-14 || 320 ||
 * 24-28 || 450 ||
 * 31-35 || 320 ||



Cast samples
Eight snow samples were cast. Number EM001 is from the NIRTran profile 001 (the top 15 cm). This is very hard, "glass foam"-like snow. EM002, EM003, EM004 document the complete profile of the NIRTran profile 002. Sample EM005 is taken from below the albedo sensor, albedo measurement 121. Sample EM006 is taken from below albedo measurement 122 and Sample EM007 is taken from below albedo measurement 123. Sample EM008 is from the snow deposited at the surface of crevasses, from the firn/white ice-field about 500 m north of the camp. Sample EM005 was about 20 cm very new drift snow (less than 24 h old). The deposition was artificially created by digging a 3 x 4 m, 0.3 m deep pit, which filled in during the day and night by drifting snow.

The microct-data is in file file://localhost/Volumes/fe_schneep/schneep/3_SPH/projects/126_Antarctica-Blue-Ice/data/ct-samples-chloe/summary_for_nirtran.xls

**δ18O**
50 samples were measured by Nancy Bertler, from the top 50 cm 

More samples prepared: see table

The complete dataset to a depth of 479 cm is here:

The figure that gives an idea about the chaotic distribution:

=Pb-210 dating= Margit Schwikovski from Paul-Scherrer-Institute (PSI) will date 50 samples. The samples were cut with a handsaw parallel to the core (average) each sample is between 180-220 g, and about 30 cm long. The bottles were named after the bag number according to the sheet CoreInventoryShipment.xls. The file is updated (2011-06-03) A few samples have two bag numbers, because the samples were too short. Cutting and packing (Martin and Sabine Leisinger): 2011-05-25 Transported by car to PSI: 2011-05-26 The samples were analyzed, but only the top one shows a signal, the rest is just the background signal - so the snow must be really old

**Deep 5 m core tomographies**
Segmentation parameters (from VOI) sigma 0.8, support 1, threshold 112 (5.10), 115(5.6) (5., 122 (5.3) > choose for all 115 Samples nach Tomographie in Tupperware gelegt 2012-04-04). Top mit schwarzem Punkt markiert (für texture analysis)
 * samplenumber || depth(cm) || bog/bag || effectiv_depth(cm) || CT_BlueIce || CT_sample_#r || CT_meas_# ||
 * 1 || 0 || 6/125 || no snow left || -- || - || - ||
 * 2 || 32 || 6/125 || no snow left || -- || - || - ||
 * 3 || 64 || 6/126 || 60-63 || 5.3 || 746 || 4147 ||
 * 4 || 93 || 6/127 || 89-93 || 5.4 || 752 || 4156 ||
 * 5 || 148 || 5/122 || 151-154 || 5.5 || 753 || 4157 ||
 * 6 || 202 || 5/124 || 205-206 || 5.6 || 748 || 4149 ||
 * 7 || 262 || 5/118 || 255-259 || 5.7 || 754 || 4158 ||
 * 8 || 305 || 5/120 || 298-302 || 5.8 || 755 || 4159 ||
 * 9 || 413 || 1/103 || 405-408 || 5.9 || 749 || 4150 ||
 * 10 || 489 || 4/116 || 467-471 || 5.10 || 747 || 4148 ||