Role of tropical cyclones in determining ENSO characteristics

Here we investigate the impact of TC winds on ENSO using a suite of Earth system model experiments where we insert TC winds, extracted from a TC-permitting high-resolution simulation, into a low-resolution model configuration with nearly no intrinsic TCs.

The presence of TC winds in the model increases ENSO power and shifts ENSO frequency closer to what we observe. TCs lead to an increase of strong to extreme El Nino events seen in observations and not simulated in the low-resolution model without intrinsic TCs, mainly through enhanced zonal advection feedback and thermocline feedback. Our results indicate that TCs play a fundamental role in producing the ENSO characteristics we experience today in the climate system and point to a two-way climatological interaction between TCs and ENSO.