EGU2020-5528, updated on 13 Apr 2023
https://doi.org/10.5194/egusphere-egu2020-5528
EGU General Assembly 2020
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

A breakdown of the link between the Arctic and North Atlantic Oscillations in warm climate projections

Mostafa Hamouda1, Claudia Pasquero2, and Eli Tziperman3
Mostafa Hamouda et al.
  • 1Department of Earth and Environmental Sciences, Universita' di Milano Bicocca, Milan, Italy (m.hamouda@campus.unimib.it)
  • 2Department of Earth and Environmental Sciences, Universita' di Milano Bicocca, Milan, Italy (claudia.pasquero@.unimib.it)
  • 3Department of Earth and Planetary Sciences and School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts (eli@eps.harvard.edu)
The North Atlantic Oscillation (NAO) and the Arctic Oscillation (AO) are climate variability modes significantly affecting temperature and precipitation variability in the mid-latitudes of the Northern hemisphere. In this study, we use both reanalysis data and model historical and warmer climate simulations to show that the relation between the two oscillations may change dramatically in a different climate. In the current climate, these two climate modes are highly correlated, as they are both strongly influenced by downward propagation of stratospheric anomalies into the troposphere. When considering a warmer climate scenario (RCP8.5 in the XXIII century), the correlation between NAO and AO drops significantly, revealing that they become two separate modes of variability. The stratosphere remains an important precursor for NAO, while the AO consistently precede stratospheric anomalies. The analysis suggests that these changes are owed to land-sea thermal contrast intensification in the Pacific region, which becomes more favorable for storm variability.

How to cite: Hamouda, M., Pasquero, C., and Tziperman, E.: A breakdown of the link between the Arctic and North Atlantic Oscillations in warm climate projections, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5528, https://doi.org/10.5194/egusphere-egu2020-5528, 2020.

Displays

Display file