Seismic Ocean Thermometry

CLIMATE CHANGE RESEARCH CENTRE / SCHOOL OF MATHEMATICS & STATISTICS

More than 90% of the energy trapped on Earth by increasingly abundant greenhouse gases is absorbed by the ocean. Monitoring the resulting ocean warming remains a challenging sampling problem. To complement existing point measurements, we introduce a method that infers basin-scale deep-ocean temperature changes from the travel times of sound waves that are generated by repeating earthquakes. The first implementation of this seismic ocean thermometry constrains temperature anomalies averaged across a 3000-kilometre-long section in the equatorial East Indian Ocean with a standard error of 0.0060 kelvin. Between 2005 and 2016, we find temperature fluctuations on time scales of 12 months, 6 months, and ~10 days, and we infer a decadal warming trend that substantially exceeds previous estimates.

 

Speakers:

Dr Wenbo Wu & Dr Jörn Callies -  Division of Geological and Planetary Sciences, California Institute of Technology.

 

Speaker Biography: 

Dr Wenbo Wu is a postdoc scholar in seismology working at the seismological laboratory at the California Institute of Technology. He received his B.Sc./M.Sc. degrees from the University of Science and Technology of China (USTC). He obtained a PhD degree in geophysics from the department of Geosciences at Princeton University. His research interests are seismic ocean thermometry, numerical methods of seismic wave propagation and deep Earth seismic structure.

Dr Jörn Callies is Assistant Professor of Environmental Science and Engineering at the California Institute of Technology. He holds a B.Sc./M.Sc. in meteorology from the University of Hamburg, Germany, and a PhD in physical oceanography from the Massachusetts Institute of Technology and Woods Hole Oceanographic Institution Joint Program in Oceanography.