About the project
Climate models predict a more El Niño-like climate under global warming, but observations during the past 60 years suggest changes of opposite sign. This project will combine knowledge of physical processes and state-of-the-art Artificial Intelligence-based approaches to extend climate records back 200 years and reinvestigate this discrepancy.
El Niño represents the biggest fluctuation in Earth’s climate system. It is characterized by weakening of the east-west temperature gradient across the Equatorial Pacific, which weakens zonal atmospheric circulation, increases mean surface temperature, and alters global hydrological cycles. Therefore, understanding how this temperature gradient will change in a warming climate has crucial implications for accurate climate projections.
Climate scientists, however, do not know the answer. Whereas physics-based climate models predict a more El Niño-like climate with weakening gradient, observational estimates from 1960-2022 suggest an enhanced gradient.
Different explanations have been proposed to understand this model-data discrepancy (Watanabe et al., 2024). In this project, you will take a different perspective, extending the high-quality observational data to 200 years, to seek more robust comparisons and conclusions.
Specifically, you will use sea surface temperature (SST) and its physically coupled quantity, sea-level pressure (SLP), to reconstruct historical tropical climate, with three objectives,
- Correcting 1850-onward SLP records in the International Comprehensive Ocean-Atmosphere Dataset. SST records have been corrected by Chan (Chan et al., 2024), and a set of tools are ready to use;
- Developing and applying AI-based techniques (e.g., Kadow et al., 2018) to reconstruct dynamically consistent tropical SST and SLP evolution since 1850; and
- Investigating long-term trends in tropical Pacific climate using the updated reconstruction, compared with model simulations.
Result of this project is a dynamically consistent temperature and pressure dataset since 1800 and your answering how and why equatorial SST gradient has changed and will change in the future.
