Fig. 6. Sea ice thickness derived from ALS surface elevation and EMIRAD-2 brightness temperature (TB) on March 24, 2014. The thin and thick lines represent 2 s and 20 s averages, respectively. The TB is averaged along track and the freeboard is averaged along and across-track for ALS. EMIRAD-2 measured TB near nadir while the SMOS TB is the average between nadir and 40° taken from the closest grid cells. The values for the ice thickness from SMOS were taken from the UH product and the same algorithm was used to derive the ice thickness from EMIRAD-2 TB. The thick black line indicates the sea ice thickness derived with the assumption of hs = 0.1 · hi while the upper limit of the grey shaded area is calculated without snow. The dashed lines indicate the mean values when only the first and last 15 min are considered.