PHYS 450: Arctic Geophysics
The purpose of the trip is to investigate a possible correlation between the surface temperature of arctic sea ice and the thickness of the sea ice.
On a previous trip in 2012, data collected suggested these quantities were correlated. Unfortunately, there was not enough data collected to statistically prove the correlation. The 2014 trip will focus on collecting both thermal and resistivity data that will be correlated to data collected by drilling into the sea ice.
In order to determine the total volume of the north polar sea ice cap the researchers will need to collect sea ice thickness data. Pairing the thickness of the sea ice with already established knowledge of the surface area allows for the volumetric calculation of the sea ice. Knowledge of the volume of the sea ice will allow a more accurate assessment of the extent of the ice and rate at which it is melting.
Current methods of determining thickness are time consuming and often cover only small areas. The bottom of the sea ice isn’t smooth which further complicates the ability to accurately measure the thickness.
If the team establishes a strong correlation between surface temperature and sea ice thickness, then they will be able to state that a specific surface temperature indicates a specific thickness. By using current thermal instrumentation, the research team hopes to confirm this correlation.
The team will work to investigate this correlation by deploying a custom thermal infrared sensor that has been developed, built, tested, and redesigned based on student input from previous trips. This sensor will be used on the surface of the sea ice simultaneously with an electrical resistivity array, which measures how well an electrical signal is transmitted through different materials.
Specialized software uses the surface resistivity data to build a cross-sectional image of the electrical properties of the ice. The depth of the ice is determined where the electrical properties of the ice yield to those of the water.
While the software can make a reasonable approximation of this ice/water boundary, it is still a model, and thus requires drilling in a statistically-significant number of locations to make an exact determination of that boundary. Therefore the drilling is the key component that ties the resistivity readings to the actual sea ice thickness, which is then correlated with the surface temperature. The researchers will also be exploring other methods of obtaining sea ice surface temperatures to extend the current methods.