Abstract The long-term response of the Atlantic meridional overturning circulation (AMOC) to climate change remains poorly understood, in part due computational expense associated with running atmosphere–ocean general models (GCMs) equilibrium. Here, we use a collection millennial-length GCM simulations examine transient and equilibrium responses AMOC an abrupt quadrupling atmospheric carbon dioxide. We find that GCMs consistently simulate weakening during first century but exhibit diverse...

Abstract Air‐sea exchanges across oceanic fronts are critical in powering cloud formation, precipitation, and atmospheric storms. Oceanic submesoscale of scales 1–10 km characterized by strong sea surface temperature (SST) gradients. However, it remains elusive how affect the overlying atmosphere due to a lack high‐resolution observations or models. Based on rare situ Kuroshio Extension region, we quantify air‐sea an front. The cross‐front SST turbulent heat flux gradients reaches 2.4°C/km...

The Antarctic sea ice area expanded significantly during 1979-2015. This is at odds with state-of-the-art climate models, which typically simulate a receding cover in response to increasing greenhouse forcing. Here, we investigate the hypothesis that this discrepancy between models and observations occurs due simulation biases drift velocity. As control use Community Earth System Model (CESM) Large Ensemble, has 40 realizations of past future change all undergo retreat recent decades. We...

Abstract Marine heatwaves (MHWs) exert devastating impacts on ecosystems and have been revealed to increase in their incidence, duration, intensity response greenhouse warming. The biologically productive eastern boundary upwelling systems (EBUSs) are generally regarded as thermal refugia for marine species due buffering effects of ocean However, using an ensemble state-of-the-art high-resolution global climate simulations under a high carbon emission scenario, here we show that the MHW...

Abstract Paleoclimate proxy data suggest that the Atlantic Meridional Overturning Circulation (AMOC) was shallower at Last Glacial Maximum (LGM) than its preindustrial (PI) depth. Previous studies have suggested this shoaling necessarily accompanies Antarctic sea ice expansion LGM. Here influence of Southern Ocean surface forcing on AMOC depth is investigated using ocean‐only simulations from a state‐of‐the‐art climate model with specified output previous coupled PI and LGM simulations. In...

Abstract Paleoclimate proxy evidence suggests that the Atlantic meridional overturning circulation (AMOC) was about 1000 m shallower at Last Glacial Maximum (LGM) compared to present. Yet it remains unresolved what caused this glacial shoaling of AMOC, and many climate models instead simulate a deeper AMOC under LGM forcing. While some studies suggest Southern Ocean surface buoyancy forcing controls depth, others have suggested alternatively North or interior diabatic mixing plays dominant...

Abstract The reorganization of the Atlantic meridional overturning circulation (AMOC) is often associated with changes in Earth’s climate. These AMOC are communicated to Indo-Pacific basins via wave processes and induce an anomaly that opposes on decadal centennial time scales. We examine role this transient, interbasin response, driven by weakening, both ocean-only model idealized geometry a coupled CO 2 quadrupling experiment, which ocean warms two distinct scales: fast surface warming...

Abstract Previous studies have suggested that the global ocean density stratification below ∼3000 m is approximately set by its direct connection to Southern Ocean surface density, which in turn constrained atmosphere. Here role of forcing glacial‐interglacial changes investigated using a comprehensive climate model and an idealized conceptual model. found control deep up ∼2000 m, much shallower than previously thought contrary expectation North Atlantic should strongly influence at...

Abstract Climate models consistently project (i) a decline in the formation of North Atlantic Deep Water (NADW) and (ii) strengthening Southern Hemisphere westerly winds response to anthropogenic greenhouse gas forcing. These two processes suggest potentially conflicting tendencies meridional overturning circulation (AMOC): weakening AMOC due changes but Ocean. Here we focus on transient evolution global ocean perturbation NADW rate. We propose that adjustment Indo-Pacific is critical...

Abstract In this paper, seasonal variation of the South Equatorial Current (SEC) bifurcation off Madagascar coast in upper south Indian Ocean (SIO) is investigated based on a new climatology derived from World Database and 19-year satellite altimeter observations. The mean integrated over thermocline around 18°S reaches southernmost position June/July northernmost November/December, with north–south amplitude about 1°. It demonstrated that linear, reduced gravity, long Rossby model, which...

Abstract Temporal and spatial variations in the ocean surface mixed layer are important for climate ecological systems. During 1980–2019, Southern Indian Ocean (SIO) depth (MLD) displays a basin‐wide shoaling trend that is absent other basins within 40°S–40°N. The SIO MLD mostly prominent austral winter with deep climatology MLD, substantially weakening seasonality. Moreover, changes primarily caused by southward shift of subtropical anticyclonic winds hence gyre, associated strengthening...

Abstract The ocean is a magnificent reservoir of kinetic energy possessed by currents at diverse spatio-temporal scales. These transport heat and material, regulating the regional global climate. It generally thought that large-scale circulations should become more energetic under warming, especially in ocean’s upper layer. However, using high-resolution climate simulations, here we demonstrate total projected to be significantly reduced warming climate, despite overall acceleration This...

Abstract Climate models consistently project a robust weakening of the Indonesian Throughflow (ITF) and Atlantic meridional overturning circulation (AMOC) in response to greenhouse gas forcing. Previous studies ITF variability have largely focused on local processes Indo‐Pacific Basin. Here, we propose that much centennial‐scale is dynamically linked changes Basin communicated between basins via wave processes. In an AMOC slowdown, Indian Ocean develops northward surface transport anomaly...

Abstract The subpolar gyres of the Southern Ocean form an important dynamical link between Antarctic Circumpolar Current (ACC) and coastline Antarctica. Despite their key involvement in production export bottom water poleward transport oceanic heat, these are rarely acknowledged conceptual models circulation, which tend to focus on zonally averaged overturning across ACC. To isolate effect regional we carried out a set numerical simulations with idealized representations Weddell Sea sector...

Abstract Previous observation and model studies show that the upper-ocean stratification is enhanced under global warming (Capotondi et al.; Cravatte Deser al., etc.). The response of recirculation, which associated with western boundary current (WBC) jet extension significantly increases its transport, to intensified stratification, studied in a two-layer quasigeostrophic ocean circulation model. It found barotropic transport first but then decreases as result saturation surface-layer...

Abstract Interactions between the open ocean and marginal seas have been suggested to be critical redistribution dissipation of global energy. Here, we propose a mechanism for upper influencing deep flow in that hinges on formation propagation topographic Rossby waves (TRWs). Observations high‐resolution simulations suggest substantial intraseasonal variability with periods 5–60 days associated over continental slopes northern South China Sea (NSCS). These fluctuations generally account 40%...

Abstract The Agulhas Current (AC) is a critical component of the global ocean circulation. Climate models consistently project AC to decline in 21st century. Previous studies typically attributed weakening changes Indian Ocean wind and/or Indonesian Throughflow (ITF) transport. However, our analysis suggests that local surface and ITF can only explain portion model‐simulated changes. Using hierarchy models, we show Atlantic Meridional Overturning Circulation (AMOC) strength warming climate...

Anthropogenic warming is projected to enhance Arctic freshwater exportation into the Labrador Sea. This extra may weaken deep convection and contribute Atlantic Meridional Overturning Circulation (AMOC) decline. Here, by analyzing an unprecedented high-resolution climate model simulation for 21st century, we show that Current strongly restricts lateral spread of from Ocean open ocean such input has a limited role in weakening overturning circulation. In contrast, absence strong with lower...

Abstract The interannual variability of the upper-ocean circulation forced by seasonally varying monsoonal wind is investigated in a two-layer quasigeostrophic (QG) model, with aim to understand low-frequency South China Sea (SCS) circulation. It demonstrated that can force significant internal variability, which mainly associated intrinsic nonlinear dynamics summer double-gyre system. This arises from fact characterized Rossby wave adjustment winter single-gyre system, much weaker than...

Abstract The Agulhas Current (AC) is a critical component of global ocean circulation. However, due to lack multidecadal observations, it not clear how the AC has changed in response anthropogenic forcing. A recent observational study suggests broadening and slight weakening past few decades, while others suggest strengthening during historical period. In this paper, we find substantial internal variability on decadal time scales high-resolution models. We show that consistently exhibits two...

Mixing induced by oceanic mesoscale eddies can affect tracer distributions in the ocean and thus modulate evolution of physical biochemical marine system. In context global warming, regionally different trends eddy mixing could exist. Motivated this hypothesis, we quantified trend surface diffusivity, a metric widely used to quantify rate, using satellite altimetry data. The average particle-based diffusivity increases 284.1 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"...

Abstract The response of the South China Sea (SCS) circulation to intraseasonal variability summer monsoon is studied with both observations and a 1.5-layer reduced-gravity model. Intraseasonal SCS characterized by evolution wind jet intensity in midbasin typical amplitude 6 m s −1 several peaks on its power spectrum between 10 60 days. However, this study finds that sea surface height (SSH) presents significant southeast Vietnam cm period only 40 This implicates frequency selectivity...

Recent research offers new insights on Antarctic sea ice, which, despite global warming, has increased in overall extent over the past 40 years.