| Abstrakt: |
Measuring the temperature changes of the deep ocean will be critical to understanding how the earth system will respond to climate change. In this work, we present a method for measuring the depth‐averaged, deep ocean temperature at local (∼3 km) spatial scales using passive estimates of acoustic propagation. These passive acoustic estimates of deep ocean temperature can be used with existing and future passive acoustic monitoring infrastructure to provide complimentary observations of the ocean to in situ measurements, and could be particularly useful in areas of poor ocean observation coverage. Using 8 years of ambient sound data, we demonstrate that the passive estimates agree with global ocean models and measurements by ARGO floats. The rms difference between the HYCOM ocean model is shown to be 0.13°C, and the rms difference between ARGO measurements is shown to be 0.086°C. Plain Language Summary: In this work, we demonstrate that the ambient sound in the ocean can be used to measure local, depth‐averaged, deep ocean temperature. Using 8 years of ambient sound, we compare the estimate of ocean temperature to a global ocean model and ocean temperature measurements. The observations of deep‐ocean temperature estimated from ambient sound are shown to be consistent with the ocean model and direct measurements. This technique could eventually be used as a method for observing the deep ocean and be used as data assimilation into global ocean models. Key Points: Using coherent ambient sound, surface reflection acoustic arrival times are estimated with a high accuracy (∼1 ms)These estimates of acoustic travel time are then used to estimate the depth‐averaged water temperature in the deep oceanIn this work, we demonstrate the feasibility of using passive acoustic monitoring infrastructure to observe deep ocean temperature [ABSTRACT FROM AUTHOR] |
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