Oceanic El-Ni\~{n}o wave dynamics and climate networks

TL;DR

This study uses climate network analysis on satellite sea surface height data to identify and characterize oceanic waves like Kelvin and Rossby waves, revealing their roles in climate dynamics and potential for improved prediction.

Contribution

It introduces a novel climate network approach to quantify oceanic wave characteristics and links network hubs with wave initiation and dissipation locations.

Findings

Network hubs correspond to Kelvin wave initiation and dissipation sites.

Dissipation at 140°W is weaker during El Niño events.

Hubs align with wind burst activity and vorticity related to Rossby waves.

Abstract

Oceanic Kelvin and Rossby waves play an important role in tropical climate and \en dynamics. Here we develop and apply a climate network approach to quantify the characteristics of \en related oceanic waves, based on sea surface height satellite data. We associate the majority of dominant long distance ($\geq 500$ km) links of the network with (i) equatorial Kelvin waves, (ii) off-equatorial Rossby waves, and (iii) tropical instability waves. Notably, we find that the location of the hubs of out-going ($\sim 180^{\circ}\rm{E}$) and in-coming ($\sim 140^{\circ}\rm{W}$) links of the climate network coincide with the locations of the Kelvin wave initiation and dissipation, respectively. We also find that this dissipation at $\sim 140^{\circ}\rm{W}$ is much weaker during \en times. Moreover, the hubs of the off-equatorial network coincide with the locations of westerly wind burst activity and high wind vorticity, two mechanisms that were associated with Rossby waves activity. The quantitative methodology and measures developed here can improve the understanding of \en dynamics and possibly its prediction.