Abstract:

The spatial-temporal variability of heaving mode in the ocean is critical to understanding climate variability on interannual and decadal time scales. Using reanalysis data and a reduced gravity model, we investigated the leading heaving modes in the Pacific Ocean. The heaving signals are dominated by two modes: the first mode in which thermocline depth anomalies in the eastern and western equatorial Pacific have opposite signs, and the second mode in which thermocline depth anomalies in the equatorial and subtropical Pacific Ocean have opposite signs. The time evolution of these two heaving modes and the physics leading to these two modes were explored. Results indicate that the first mode is directly linked to equatorial zonal wind anomalies, and the second mode is induced by the wind stress curl anomaly in the subtropics. Furthermore, these two leading heaving modes have profound impacts on basin-scale heat transport (with an amplitude of 5?10¹⁴W) and ocean heat content redistribution (with an amplitude of 1.5×10²⁰J) through ocean waves and Ekman transport, highlighting the importance of heaving modes in modifying the variabilities of the climate system and climate change.

Key words: Heaving mode, Pacific Ocean, ocean wave, heat transport, climate change