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9 April, 2002

Weather: Cloudy
High 27
Low 4

Working on Sigma Plot and Igor pro, two data entry and graphing software used for Dr. Jeffriesí lake ice study, I noticed the gradual decrease in heat flux. The changes of variables (snow temperatures, depth, and densities) impact this gradual decrease. After returning from lunch, Martin and I received a nice surprise from deaf students who went on a field trip to Aurora pond on April 4th. See below

thank you cards and drawings.

Heat Flow Calculations

If you've completed a physical from an Ice doctor, proceed with heat flow calculations with the following data below:

April 5th
Mean temperature gradient
-7.66490 C/m
Thermal conductivity
0.05977 W/m/K

April 6th
Mean temperature gradient
-7.01233 C/m
Thermal conductivity
0.06001 W/m/K

April 8th
Mean temperature gradient
-10.3696 C/m
Thermal conductivity
0.06018 W/m/K

The Science Behind Inverted Heat Flux

If we multiply a negative temperature gradient with thermal conductivity, we will have a negative heat flux (an upward flow). On the other hand, a positive temperature gradient will result a

positive heat flux (downward heat flow). This will happen more often at this time of year with increasing air temperatures. See below a diagram illustrating inverted heat flow.

So, What Do You Think?

We will be working at Poker Flat again tomorrow. Predict heat flow results from Jalpertia pond. Refer to April 10th journal entry for results.

1. Inverted Heat Flux and Positive Temperature Gradient: (Evidently, ice will not be present at +30 'C but to give you an idea - warmer air temperatures will invert the heat flow.)

2. Last week, a group of deaf students went to Aurora pond for some snow and ice hands on activities - here are some excellent drawings and thank you cards from them. Thanks!!

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