CAATEX: Coordinated Arctic Acoustic Thermometry Experiment

During the MOSAiC drift, two sound sourcs in fixed moorings will transmit a signal which will be received on listen cables in 5 fixed moorings and four drifting drifting receivers hundreds of kilometers away from the sound sources. 


CAATEX addresses research in the central Arctic Ocean, especially the ocean climate change. The Arctic warms rapidly, but yet the central Arctic Ocean under the sea ice is poorly observed and remains largely unknown. This project focus on

1) Collect new ocean observations covering the central Arctic Ocean

2) Obtain new knowledge about the decadal changes in heat content of the central Arctic Ocean

3) Improve our understanding of uncertainties in heat content estimates from climate models

Project Summary

 The Arctic region experiences strong climate change, but yet the central Arctic Ocean under the sea ice is poorly observed and remains largely unknown. A particular focus in CAATEX will be to obtain regional to basin scale information about ocean temperature from acoustic thermometry and standard oceanographic instrumentation. A major effort will be to design and implement the acoustic thermometry experiment including fixed mooring and moving ship thermometry. Fixed mooring thermometry will provide yearlong times series of mean ocean temperature between each of the moorings, whereas the moving ship with the fixed source moorings will scan the ocean volume during the yearlong MOSAIC drift providing mean ocean temperature along each section connecting the ship and moorings. This scanning concept will systematically map a very large portion of the upper and lower part of the central Arctic Ocean, manifesting spatial variability. The yearlong time series of mean ocean temperature and point measurements from the fixed moorings will provide information about the temporal variability on local to basin-wide scale. CAATEX will furthermore contribute to MOSAIC with multidisciplinary measurements from the Hovercraft and sea ice buoys.

The prime result from CAATEX field experiment is baseline data on mean ocean temperature and heat content of the central Arctic Ocean, which will be used for estimation of ocean climate change, as well as evaluation of global climate models. The new observations from the fixed moorings will be compared to similar observations made in 1994 and 1999 and thereby quantify how much the mean ocean temperature along the mooring array has changed over two decades. To obtain an improved estimate of the heat content of the central Arctic Ocean, the new data obtained in CAATEX will be used in combination with a high-resolution ice-ocean model. This estimate will be highly valuable for benchmarking the skill of climate models to represent Arctic Ocean heat content.

Peer Review Publications

  1. Worcester PF, Dzieciuch MA, Sagen H. Ocean Acoustics in the rapidly changing Arctic. Journal of the Acoustical Society of America. 2020;16(1).
Project Details
NERSC Principal Investigator: 
Hanne Sagen
Coordinating Institute: 
Nansen Environmental and Remote Sensing Center
Project Status: