According the Oceanic Nino Index (ONI) from NOAA Center for Weather and Climate Prediction Climate Prediction Center, RI divided into 5 phase; the first phases are strong El Nino (ONI ≥ 1.0), weak El Nino (1.0 ≥ ONI ≥ 0.5), Neutral (0.5 ≥ ONI ≥ -0.5), weak La Nina (-0.5 ≥ ONI ≥ -1.0), and strong La Nina (ONI ≤ -1.0), respectively. It is shown that systematic difference for the onset, lifetime maximum intensity (LMI), and genesis locations of RI TC. When TC under the strong El Nino tend to form lower and more right region. However, the there is no significant difference in OHC and SST between these 5 phase.
For the vertical wind shear, statistically significant difference is examined between RI and Non-RI. RI events occur under weaker vertical wind shear environment than Non-RI events. The vertical wind shear at the LMI of RI cases also show consistent results. Meanwhile, the LMI of RI cases are more intense than the LMI of Non-RI case.