Atmosphere Ocean Science Colloquium
Using earthquakes to measure ocean warming
Speaker: Joern Callies, Caltech
Location: Warren Weaver Hall 1302
Date: Wednesday, October 12, 2022, 3:30 p.m.
More than 90% of the energy trapped on Earth by increasingly abundant greenhouse gases is absorbed by the ocean. Despite much progress over the past 20 years, monitoring the resulting ocean warming remains a challenging sampling problem. In this talk, I will present a new method that complements existing point measurements by inferring basin-scale deep-ocean temperature change from the travel times of sound waves that are generated by repeating earthquakes. I will show results from two sections in the East Indian Ocean that are 2900 and 4400 km long. The measurements capture deep-ocean temperature variations on time scales from a few days to a decade. The approximate vertical structure of these variations can be inferred using measurements at different frequencies. I will argue that the new method, if extended globally, offers useful new constraints on the deep-ocean uptake and transport of heat.