Fig. 3: Upper ocean stratification from comparison of shipboard and mooring data.

a, b Salinity [] and c, d potential density [kg m−3] in 2017 (meltwater regime in a, c) and 2018 (mixed layer regime in b, d). All CTD/UCTD casts within 35 km of HG-IV mooring location (gray lines). All CTD casts within 10 km of HG-IV (black lines). All mooring measurements between 01-May and 01-Aug at ~30/~55 m (blue/red dots). Mooring measurements within 24 h of black profiles (large blue/red dots). Note that the aspect ratio of the subplots of the respective parameters is identical.