Contrasting the Flow Patterns in the Equatorial Pacific Between Two Types of El Nino

Outputs based on the National Centers for Environmental Prediction (NCEP) Global Ocean Data Assimilation System (GODAS) are adopted to contrast the current variations in the equatorial Pacific between two types of El Nino. The model fully resolves the equatorial currents. We found that the central Pacific El Nino (CP-El Nino) corresponds well with previous El Nino studies in that both the eastward Equatorial Undercurrent (EUC) and westward South Equatorial Current (SEC) weaken. On the other hand, the eastern Pacific El Nino (EP-El Nino) displays a distinct circulation pattern. The North Equatorial Countercurrent (NECC) strengthens in the developing phase and persists into the peak of the warm event, whereas the northern branch of the SEC (SECn) also intensifies during the mature phase and lasts for about six months. The South Equatorial Countercurrent (SECC) strengthens during the decaying phase of the EP-El Nino. The shifting of the wind stress curl associated with the thermocline variability is chiefly responsible for the unique current performance of the EP-El Nino. It is worth noting that the air-sea interaction plays an important role in the current variability not only during a CP-El Nino but also during an EP-El Nino.