Thermistor strings

Instrument: Thermistor strings (YSI44080)
Uncertainty: Temperatures are accurate to 0.1C for most of the year. 
There were some problems during summer melt due to solar heating of the probes.
File format: The temperature data from the thermistor strings is in is a 
directory THERM. There is a separate file for each temperature site. All files 
are ASCII comma separated variable format. The first row of the file is the 
position of the thermistors when installed. The ice surface is zero with postive 
positions above the surface and negative below. Subseqent rows have the date-time 
in the first column and temperatures in the following columns. 

The building block of the strings was a 1 m long PVC rod with 10 thermistors 
spaced every 10 cm. These rods could easily be connected to assemble strings 
that extended from the air through the snow and ice into the upper ocean. The 
default spacing was 10 cm, though occassionally strings were overlapped to 
provide 5 cm spacing. Temperatures were automatically logged every hour. 
YSI thermistors, with an accuracy better than 0.1 C, were used. Thermistor 
strings appeared to work quite well during the cold portion of the year. 
However, there were some problems during the melt season. In general, during 
summer, solar heating of the strings resulted in measured air temperatures 
that were too high. Also, ponding resulted in a couple of the strings melting 
out during summer (Quebec 1, Baltimore). Zero depth is the ice surface at 
installation, with positive depths being in the snow and air and negative
depths in the ice and upper ocean.

Thermistor strings were installed at:
Pittsburgh - SHEBA column site, undeformed multiyear
The Ridge - thick second year ridge, 
Quebec 1 - thinner, multiyear
Quebec 2 - thick multiyear
Seattle - ponded area, hummocks nearby
Tuk - mature multiyear ridge
Baltimore - first-year ice