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Oral

IAPSO

JPCM08 - Impacts of climate change on the ocean

Observed multi-decadal increase in the surface oceans thermal inertia

1. Chaehyeong  Lee, University of Colorado Boulder

2. Hajoon  Song*, Yonsei University

3. Yeonju  Choi, Yonsei University

4. Ajin  Cho, Yonsei University

5. John  Marshall, MIT

*Presenting Author

The oceans surface layer has a crucial role in Earths climate, absorbing excess atmospheric heat, thereby regulating global temperatures. Here, using global daily sea surface temperature (SST) data, we document a notable increase in the persistence of SST anomalies across the global ocean since 1982. This trend is also evident in frequency space, showing a decreased variance in SSTs on timescales shorter than a month, but a slight increase on longer timescales. A simple stochastic model attributes this prolonged memory to three key factors??a deepening of the surface mixed layer, a weakening of oceanic forcing and reduced damping rates. The first two factors decrease the variance on shorter timescales, while the third increases it on longer timescales. Our findings have great relevance to the observed increase in the duration of marine heatwaves and the associated heightened thermal threats to marine organisms. Our study also suggests that the oceans ability to sequester heat is weakening.