Dynamics of the seasonal cycle of sea surface height (SSH) in the South China Sea (SCS) are studied using observations as well as numerical and theoretical models. Seasonal variability of the SCS is interpreted in light of large-scale dynamics and Rossby waves. It is found that the seasonal cycle over most of the SCS basin is determined predominantly by the regional ocean dynamics within the SCS. The SSH variability is shown to be forced mainly by surface wind curl on baroclinic Rossby waves. Annual baroclinic Rossby waves cross the basin in less than a few months, leaving the upper ocean in a quasi-steady Sverdrup balance. An anomalous cyclonic (anticyclonic) gyre is generated in winter (summer) by the anomalous cyclonic (anticyclonic) wind curl that is associated with the northeasterly (southwesterly) monsoon. In addition, surface heat flux acts to enhance the wind-generated variability. The winter surface cooling (warming) cools (warms) the mixed layer especially in the central SCS, reducing (increasing) the SSH. * Additional affiliation: Institute of Physical Oceanography, The

This paper reviews recent advances regarding land–atmosphere–ocean coupling associated with the Tibetan Plateau (TP) and its climatic impacts. Thermal forcing over the TP interacts strongly with that over the Iranian Plateau, forming a coupled heating system that elevates the tropopause, generates a monsoonal meridional circulation over South Asia and creates conditions of large-scale ascent favorable for Asian summer monsoon development. TP heating leads to intensification and westward extension (northward movement) of the South Asian High (Atlantic Intertropical Convergence Zone), and exerts strong impacts on upstream climate variations from North Atlantic to West Asia. It also affects oceanic circulation and buoyancy fields via atmospheric stationary wave trains and air–sea interaction processes, contributing to formation of the Atlantic Meridional Overturning Circulation. The TP thermal state and atmospheric–oceanic conditions are highly interactive and Asian summer monsoon variability is controlled synergistically by internal TP variability and external forcing factors.

A coupled ocean‐atmosphere model study shows that the extratropical impact on tropical climate is as strong as the tropical impact on extratropical climate. A 2°C SST warming in the global extratropics increases equatorial ocean temperature by ∼1°C in the surface and subsurface. The surface temperature change is caused by the atmospheric bridge of the Hadley circulation (70%) and the oceanic tunnel of thermocline subduction (30%), while the subsurface temperature change is forced predominantly through the oceanic tunnel. Furthermore, the dominant influence on the equator comes from the southern hemisphere atmosphere and ocean.

A coupled box model is used to study the compensation between atmosphere and ocean heat transports. An analytical solution to the Bjerknes compensation (BJC) rate, defined as the ratio of anomalous atmosphere heat transport (AHT) to anomalous ocean heat transport (OHT), is obtained. The BJC rate is determined by local feedback between surface temperature and net heat flux at the top of atmosphere (TOA) and the AHT efficiency. In a stable climate that ensures global energy conservation, the changes between AHT and OHT tend to be always out of phase, and the BJC is always valid. This can be demonstrated when the climate is perturbed by freshwater flux. The BJC in this case exhibits three different behaviors: the anomalous AHT can undercompensate, overcompensate, or perfectly compensate the anomalous OHT, depending on the local feedback. Stronger negative local feedback will result in a lower BJC rate. Stronger positive local feedback will result in a larger overcompensation. If zero climate feedback occurs in the system, the AHT will compensate the OHT perfectly. However, the BJC will fail if the climate system is perturbed by heat flux. In this case, the changes in AHT and OHT will be in phase, and their ratio will be closely related to the mean AHT and OHT. In a more realistic situation when the climate is perturbed by both heat and freshwater fluxes, whether the BJC will occur depends largely on the interplay among meridional temperature and salinity gradients and the thermohaline circulation strength. This work explicitly shows that the energy conservation is the intrinsic mechanism of BJC and establishes a specific link between radiative feedback and the degree of compensation. It also implies a close relationship between the energy balance at the TOA and the ocean thermohaline dynamics.

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