The Relationship Between the Global Mean Deep‐Sea and Surface Temperature During the Early Eocene
Résumé
Estimates of global mean near-surface air temperature (global SAT) for the Cenozoic era rely largely on paleo-proxy data of deep-sea temperature (DST), with the assumption that changes in global SAT covary with changes in the global mean deep-sea temperature (global DST) and global mean sea-surface temperature (global SST). We tested the validity of this assumption by analyzing the relationship between global SST, SAT, and DST using 25 different model simulations from the Deep-Time Model Intercomparison Project simulating the early Eocene Climatic Optimum (EECO) with varying CO 2 levels. Similar to the modern situation, we find limited spatial variability in DST, indicating that local DST estimates can be regarded as a first order representative of global DST. In line with previously assumed relationships, linear regression analysis indicates that both global DST and SAT respond stronger to changes in atmospheric CO 2 than global SST by a similar factor. Consequently, this model-based analysis validates the assumption that changes in global DST can be used to estimate changes in global SAT during the early Cenozoic. Paleo-proxy estimates of global DST, SST, and SAT during EECO show the best fit with model simulations with a 1,680 ppm atmospheric CO 2 level. This matches paleo-proxies of EECO atmospheric CO 2 , indicating a good fit between models and proxy-data.
Domaines
Océan, Atmosphère
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Paleoceanog and Paleoclimatol - 2023 - Goudsmit‐Harzevoort - The Relationship Between the Global Mean Deep‐Sea and Surface.pdf (3.05 Mo)
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