Sea Ice Bio-Optical Sampling, cruise 2007/08 V1 (SIPEX)

The hole-effect on the light measurements was assumed to be negligible due the position of the radiometer 1.2 m north (i.e. directed towards the sun) of the access hole. Under-ice high-resolution (300-900 nm, 3.3 nm band-width) irradiance spectra were recorded with a laptop computer using TriOS MSDA_XE software version 7.5.1. At each site, snow thickness was measured with a ruler (10 replicate measurements) and one ice core was collected, using a manual Kovacs Mark II ice core system (0.09 m core diameter), directly above the radiometer location.

Ice floe freeboard was determined with a ruler from the sampling hole. The length of the ice core was recorded and the ice core was placed in a clean polyethylene container and transported back to the ship's laboratories. On the ship sampled ice cores were melted at 4 degrees C in the dark within 24 - 36 hours of collection.

After the ice cores had melted, the samples were gently mixed and subsamples were taken for a) determination of ice algal pigment concentration and composition, and b) determination of particulate absorption.