Observing abnormal wind features of the tropical Pacific Ocean during the 1997-98 El Niño

The 1997-98 El Niño, the strongest in recorded history, manifested itself with unusual features associated with the Pacific wind system. These features include: (1) an annual cycle of an east-west migration of a weakened wind speed zone between 2°N-9°N; and (2) an asymmetric seesaw process of trade wind variations between the two hemispheres in terms of relative intensity and central position. These features, revealed by the multi-year TOPEX altimeter data, may serve as new clues to improve our understanding of El Niño formation, and may also contribute to its future prediction