Amplification of Winter Sea surface temperature response over East China Seas to global warming acceleration and slowdown

The global mean surface temperature does not increase monotonously over the past decades, with accelerated warming from the late 1970s to 1998 and followed by the warming slowdown during 1998-2013 (the so-called warming hiatus). This study assessed and compared the temporal evolutions of sea surface temperature (SST) trends in the East China Seas (ECS, including Bohai, Yellow and East China Sea) and other key ocean regions. The results revealed an amplified response of ECS SST to both global warming acceleration and hiatus. This amplification was manifested as remarkably enhanced winter warming rates in the ECS of over 1.1 and 0.8 degrees C.decade(-1) for the 1980-1989 and 1990-1999, respectively, and as an obvious cooling trend of nearly -0.5 degrees C.decade(-1) during 1998-2013. The enhanced response can be explained well by the combined effects of the Kuroshio Current (KC) and East Asian Winter Monsoon (EAWM). The weakened EAWM during the 1980s, accompanied by lower wind speeds and higher air temperatures, impeded the releases of latent and sensible heat fluxes from the ocean to the atmosphere, resulting in rapid ECS warming. During 1998-2013, the strengthened EAWM led to the enhanced cooling trend in the ECS. In addition, the volume transport of the KC east of Taiwan strengthened (weakened) during the 1990s (2000s), which might also have contributed to the enhanced warming (cooling) in the ECS. Our research suggests their sensitivity makes the ECS potentially vulnerable to the effects of global climate change, which has important implications regarding regional impact assessments.