24 January, 2002

Weather High ~20, Low ~37 Bitter cold!

I saw my first Sundog (Parhelia) today. This stunning ice crystal halo, observed from the Geophysical Institute looked like a vertical cylindrical rainbow. Often found in Antarctica, these light phenomena also appear in other areas with similar climates. Ice crystals formed in air retract light in various degrees portraying rainbow-like colors in cylindrical or arc shapes. For more information on Parhelia:

http://www.gi.alaska.edu/ScienceForum/ASF7/750.html

http://www.chemtrailcentral.com/phenom.shtml

http://www.sundog.clara.co.uk/halo/parhelia.htm

As explained yesterday, Sandra (previous TEAntarctic teacher) is visiting from Seattle to consult with Martin (Dr. Jeffries) on one of his projects. This afternoon, Sandra and I worked together calculating raw data from Aurora pond. I've been here for almost two weeks and I still find data calculation the most difficult but rewarding experience of this project.

Topic of the Day

What is a hot-wire ice thickness gauge? To review, a hot-wire gauge is an instrument used to measure ice thickness in a non- destructive manner (as opposed to drilling). See diagrams below.

1. The aluminum L-shaped tube, securely staked in ice, contains a loop of resistance wire of known length attached to a toggle (metal weight). The resistance wire runs from the black connector through the tube and toggle to the wooden handle. L1 is the length from the wooden handle to the base of the snow.

2. When the resistance wire is heated with a 12 Volt battery, the ice melts just enough for the wire to slide through until the toggle hits the base of the ice. L2 is the length between the wooden handle to the aluminum tube. To determine ice thickness, the sum of L1 and L2 is subtracted from the total wire length.

3. Measuring L1 - (base of snow to wooden handle)

4. Measuring L2 - (wooden handle to aluminum tube)