Long-term variability of sea surface temperature in Taiwan Strait

Long-term variability of sea surface temperature (SST) in the Taiwan Strait was studied from the U.K. Met Office Hadley Centre climatological data set HadISST1. In 1957-2011, three epochs were identified. The first epoch of cooling SST lasted through 1976. The regime shift of 1976-1977 led to an extremely rapid warming of 2.1 degrees C in 22 years. Another regime shift occurred in 1998-1999, resulting in a 1.0 degrees C cooling by 2011. The cross-frontal gradient between the China Coastal Current and offshore Taiwan Strait waters has abruptly decreased in 1992 and remained low through 2011. The long-term warming of SST increased towards the East China Sea, where the SST warming in 1957-2011 was about three times that in the South China Sea. The long-term warming was strongly enhanced in winter, with the maximum warming of 3.8 degrees C in February. The wintertime amplification of long-term warming has resulted in a decrease of the north-south SST range from 5 to 4 degrees C and a decrease in the amplitude of seasonal cycle of SST from 11 to 8 degrees C.