Temperature under landfast sea ice from a thermistor mooring in Wolstenholme Fjord, Greenland, March - April 2017

The principal investigators of this project designed and tested an integrated underwater acoustic sensor network for ice-covered seas. The sensor and communication network will support 1) long-term, intelligent distributed Arctic observing systems, 2) assimilation of remote-sensing and in-situ under-ice measurements, and 3) regional and global climate modeling with real-time measurements. Such a network holds the promise to revolutionize under-ice ocean sampling in polar regions. Ocean temperatures in Wolstenholme Fjord adjacent to Thule Air Base (TAB) in Greenland were profiled at 20 discrete vertical location below the sea ice at a single mooring location in March and April of 2017. The fjord was covered by land-fast sea ice and thus provided a stable platform from which to test, deploy, and recover a range of oceanographic and acoustic sensor systems via snowmobiles during day-light hours when air temperatures are generally above -25 °C. The thermistor string was collocated with acoustic recorders, an automated weather station, and a single Sea Bird Electronics (SBE) 37sm Conductivity-Temperature-Depth (CTD) instrument. The latter sensor reported through the weather station as did the acoustic recorder.