The Role of Tidal Mixing in Regulating the Poleward Meridional Heat Transport

Abstract Based on an earth‐system climate model, a series of numerical experiments with different scaling factors of tidal mixing parameterization were conducted to study the impact of tidal mixing diffusivity on global meridional heat transport (MHT) in the ocean. Results show that an increase in vertical diffusivity κ associated with tidal mixing can enhance poleward MHT in most of the global ocean by strengthening the overturning circulations in the North Atlantic Ocean, the Indian Ocean, and the Pacific Ocean (located in the Southern Hemisphere), and weakening it in the Southern Ocean. A mathematical fitting reveals that MHT follows a power‐law relationship with κ by a coefficient of about 0.1, that is, MHT pw ∝ κ 0.1 . This is the first time to quantify the relationship between tidal mixing strength and poleward MHT, shedding light on the influence of tides on global climate change.