Pacific Ocean circulation rebounds

Abstract

Recent observations indicate that the shallow meridional overturning circulation in the tropical Pacific Ocean has rebounded since 1998, following 25 years of significantly weaker flow. Convergence of cold interior ocean pycnocline water towards the equator increased to 24.1 ± 1.8 × 10 6 m 3 s −1 during 1998–2003 from a low of 13.4 ± 1.6 × 10 6 m 3 s −1 during 1992–98. Intensified circulation led to the development of anomalously cool tropical Pacific sea surface temperatures, which may have affected Pacific marine ecosystems and global climate. The abruptness of the rebound also obscures presumed anthropogenic warming trends in the instrumental temperature record of the tropical Pacific.