EGU22-1083
https://doi.org/10.5194/egusphere-egu22-1083
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Projected Future Changes in Equatorial Wave Spectrum in CMIP6

Hagar Bartana1, Chaim Garfinkel1, Ofer Shamir2, and Jian Rao3
Hagar Bartana et al.
  • 1Hebrew University of Jerusalem
  • 2Courant Institute of Mathematical Sciences
  • 3Nanjing University of Information Science and Technology

The simulation of the Madden-Julian Oscillation (MJO) and convectively coupled equatorial waves (CCEWs) is considered in 13 state-of-the-art models from phase 6 of the Coupled Model Intercomparison Project (CMIP6). We use frequency-wavenumber power spectra of the models and observations for Outgoing Longwave Radiation (OLR) and zonal velocity at 250 hPa (U250), and consider the historical and end-of-century projections for the SSP245 and SSP585 scenarios. The models simulate a spectrum quantitatively resembling that observed, though systematic biases exist. MJO and Kelvin waves (KW) are mostly underestimated, while equatorial Rossby waves (ER) are overestimated. The models project a moderate future increase in power for the MJO, a robust increase for Kelvin waves (KW) and weaker power values for most other wavenumber-frequency combinations, including higher wavenumber ER. In addition to strengthening, KW also shift toward higher phase speeds (or equivalent depths). Models with a more realistic MJO in their control climate tend to simulate a stronger intensification, and models with a more realistic KW in their control climate tend to simulate a weaker intensification. 

 

How to cite: Bartana, H., Garfinkel, C., Shamir, O., and Rao, J.: Projected Future Changes in Equatorial Wave Spectrum in CMIP6, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1083, https://doi.org/10.5194/egusphere-egu22-1083, 2022.

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