A new view of the Eocene greenhouse world from paleoclimate data assimilation
Abstract
The Eocene, as the most recent greenhouse world, offers valuable lessons about how the climate system behaves under high levels of CO2 (ca. 1000 ppm). However, our understanding of Eocene climate dynamics is fundamentally limited by uncertain, and spatially and temporally restricted, paleoclimate data. Conversely, climate model simulations are only our best "guess" of what happened based on physical expectations. Paleoclimate data assimilation provides a way forward by formally combining the model simulations and the data. Here, we present some initial results from data assimilation of geochemical proxies for ocean temperature with simulations done with the isotope-enabled NCAR Community Earth System Model (iCESM). Our assimilation technique uses a Bayesian forward models and Eocene simulations conducted under various levels of CO2 (1X to 9X PAL). The assimilated model fields provide data-informed insights into climate parameters that we have no specific proxies for, such as global patterns in precipitation. Although continental configurations do alter the patterns of observed change in high CO2 worlds, there are basic features of the response that share a close similarity with future climate predictions, suggesting that the Eocene can inform the future more directly than is sometimes supposed.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMPP24C..08T
- Keywords:
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- 9604 Cenozoic;
- INFORMATION RELATED TO GEOLOGIC TIME;
- 4914 Continental climate records;
- PALEOCEANOGRAPHY;
- 4928 Global climate models;
- PALEOCEANOGRAPHY;
- 4954 Sea surface temperature;
- PALEOCEANOGRAPHY