1. South Pole Tank Test
This presentation contains some information about the tank sensors and measurements

2. Map of temperature sensors12 13 14 15 16 17 18 19 20 21 22 23 1 2 3 4 5 6 7 8 9 10 11
-10
-23
-41
-56
-71
-86
-102
-117
Depths (cm) of
sensors. (Tank is
122cm; Ice surface is at
-22 cm in Tank10 and at
-34 cm in Tank09
24 is inside box; are at various locations inside tent

3. Freeze rate Solve Serap’s equation with external power input:
dh/dt = 1.57E-7 (m/s)
x {T/20}
x {1/h x (P/100)}
(T is surface temperature of ice)
Result shown by lines in figure:
Crosses based on side temps
Circles based on # sump cycles
Data points very approximate indicate some concavity
Puzzle: why is the ice not deeper?
Tsurface > -20 ?
Heat from Sun ?

4. Tank temperatures Significant diurnal and semi-diurnal variations:
Sensor TT01: black, outside tank at ice surface
Sensor TT04: green, 5th down on outside of tank
Sensor TT12: red, at pipe elbow under middle of tank
Sensor TT22: blue, at elbow of ejection pipe
Sensor TT28: lavender, inside tent
Significant diurnal and semi-diurnal variations:
Trench axis is along grid N-S
Ejection pipe elbow (blue) faces sun once per day around NZ noon (64,800 s EST)
Whole tank is heated at local midnight (21,600) and local noon
The fact that the sensor under the middle of the tank cycles with Sun suggests solar heating may have a major impact on freezing.

5. Correlated variation in freeze-rate

6. Sunshades On Dec 6 we set up plywood shades Starting end of Dec:
Semi-diurnal temp fluctuations stopped
But no speed-up of freeze rate
Starting end of Dec:
Remove pieces of insulation on sides of tank facing trench walls