Satellite observations of sea surface temperature (SST) show that SST in 2004, 2006, and 2016 broke the previous record in the Yellow and East China Seas (YECS). The underlying cause of the record‐breaking SSTs in the YECS is still under debate. Our analysis results demonstrate that enhanced solar radiation and weakened wind, due to a high‐pressure system over the YECS splitting from the western Pacific subtropical high, were mainly responsible for the record‐breaking SSTs in these 3 years. The enhanced solar radiation and weakened wind both depressed oceanic turbulent mixing, and more heat was concentrated in a shallower mixed layer, inducing an anomalous SST rise and resulting in the record‐breaking SSTs.

Cool-skin and warm-layer effects are important phenomena in the ocean–atmosphere system. Here, we study tropical cool-skin and warm-layer effects and their impact on surface heat fluxes using the methods proposed by Fairall et al. in 1996, i.e., the F96 cool-skin scheme and the combined warm-layer method. The results reveal strong cool-skin effects (∼−0.3 K) in the Indo-Pacific warm pool, but weak effects in the equatorial Pacific and Atlantic cold tongues. The spatial pattern of the cool-skin effect is determined by the difference in the specific humidity between the sea and air. The warm-layer effect is strong (∼0.25 K) in both the warm pool and cold tongues but weak in the trade wind regions and exhibits a spatial pattern that is inversely related to the surface wind speed. In the tropics, the cool-skin effect causes an average reduction of 11.0 W m⁻² in the heat loss from the ocean to the atmosphere, while the warm-layer effect causes an increase of 6.0 W m⁻². With respect to the F96 cool-skin scheme, four common wind-speed-dependent empirical models could not fully capture the spatial distribution of the cool-skin effect. A new empirical model that depends on the sea–air humidity difference is proposed to overcome this problem. Compared to the combined warm-layer method, when only the F96 warm-layer scheme is applied, the effect is underestimated at both low and high wind speeds. These new findings improve our understanding of the cool-skin and warm-layer effects and provide insights into their parameterization schemes. Significance Statement: The aim of this study is to improve our understanding of tropical cool-skin and warm-layer effects and to examine their impact on surface heat fluxes. In addition, we evaluate the parameterization schemes for these effects to provide insights into their improvement in ocean–atmosphere coupled models. Our results indicate that the sea–air humidity difference is likely the most important factor influencing the tropical cool-skin effect. As a result, a new empirical model that depends on the sea–air humidity difference is proposed. Furthermore, we find that existing diagnostic models underestimate the impact of the warm-layer phenomenon on the ocean–atmosphere system. Therefore, it is necessary to develop an improved parameterization scheme, especially as synchronous near-surface temperature measurements become available.

Marine heatwaves (MHWs) are a type of widespread, persistent, and extreme marine warming event that can cause serious harm to the global marine ecology and economy. This study provides a systematic analysis of the long-term trends of MHWs in the Eastern China Marginal Seas (ECMS) during summer spanning from 1982 to 2022, and occurrence mechanisms of extreme MHW events. The findings show that in the context of global warming, the frequency of summer MHWs in the ECMS has increased across most regions, with a higher rate along the coast of China. Areas exhibiting a rapid surge in duration predominantly reside in the southern Yellow Sea (SYS) and southern East China Sea (ECS, south of 28°N). In contrast, the long-term trends of mean and maximum intensities exhibit both increases and decreases: Rising trends primarily occur in the Bohai Sea (BS) and Yellow Sea (YS), whereas descending trends are detected in the northern ECS (north of 28°N). Influenced jointly by duration and mean intensity, cumulative intensity (CumInt) exhibits a notable positive growth off the Yangtze River Estuary, in the SYS and southern ECS. By employing the empirical orthogonal function, the spatio-temporal features of the first two modes of CumInt and their correlation with summer mean sea surface temperature (SST) and SST variance are further examined. The first mode of CumInt displays a positive anomalous pattern throughout the ECMS, with notable upward trend in the corresponding time series, and the rising trend is primarily influenced by summer mean SST warming. Moreover, both of the first two modes show notable interannual variability. Extreme MHW events in the SYS in 2016 and 2018 are examined using the mixed layer temperature equation. The results suggest that these extreme MHW events originate primarily from anomalous atmospheric forcing and oceanic vertical mixing. These processes involve an anomalous high-pressure system over the SYS splitting from the western Pacific subtropical high, augmented atmospheric stability, diminished wind speeds, intensified solar radiation, and reduced oceanic mixing, thereby leading to the accumulation of more heat near the sea surface and forming extreme MHW events.

It has been suggested that the intraseasonal sea surface temperature (SST) variability in the tropical oceans can be amplified by the diurnal cycle of SST (dSST). Here, by analyzing the global tropical moored buoy array for the first time, we find that the intraseasonal SST variability is indeed amplified by the dSST in most of the tropical oceans, especially in the Indo‐Pacific warm pool, but weakened in the equatorial cold tongues of the Pacific and Atlantic Oceans. Such a divergent response is associated with the difference in atmosphere‐ocean interaction processes over these two regions. In the warm pool region, SST responds to the intraseasonal atmospheric variability, resulting in in‐phase intraseasonal fluctuations between SST and dSST that amplify the intraseasonal SST variability. However, in the cold tongue region, SST drives the atmospheric changes, which leads to out‐of‐phase intraseasonal fluctuations between SST and dSST and thus the inhibition of the intraseasonal SST variability.