Question

during el niño events, the pressure systems in the pacific

multiply greatly and split into numerous highs and lows

coalesce into a single massive low - pressure system

reverse the normal surface pressure gradient

increase the normal surface pressure gradient

Explanation:

During El Niño events, the normal atmospheric - oceanic circulation patterns in the Pacific are disrupted. The Walker circulation weakens and the normal surface pressure gradient, which has high pressure in the eastern Pacific and low pressure in the western Pacific under normal conditions, is reversed.

Answer:

reverse the normal surface pressure gradient