Seismic ocean thermometry using land-based seismometers and hydrophones

As the major buffer of Earth's energy imbalance, the ocean plays a key role in regulating global climate and temperature changes. However, accurate estimation of global ocean temperature change remains a challenging sampling problem. To complement existing point measurements, we have developed a novel and low-cost method of using travel time changes of acoustic waves from repeating natural earthquakes to infer basin-scale average ocean temperature changes. In this study, we implement this method using a seismometer and two CTBTO hydrophones in the Eastern Indian ocean to infer the large-scale ocean temperature changes with a high temporal resolution. We detect not only seasonal signals, which are generally consistent with that in previous oceanographic datasets of ECCO and Argo, but also more interesting features missing in ECCO and Argo. These results suggest that seismic ocean thermometry offers new opportunities for monitoring ocean warming