Final answer:
The combined situation of El Nino and Southern Oscillation related via see-saw like changes in barometric pressure is called the El Nino Southern Oscillation (ENSO) cycle.
Step-by-step explanation:
The combined situation of both El Nino and Southern Oscillation, related via see-saw like changes in barometric pressure, is called the El Nino Southern Oscillation (ENSO) cycle. This climate pattern involves the shift between two phases: El Nino and La Nina. During El Nino, there is a band of warm ocean water in the central and east-central equatorial Pacific, while during La Nina, there is a cooling of the water in the equatorial Pacific.