Long-Term Observations of Interannual and Decadal Variation of Sea Surface Temperature in the Taiwan Strait

Long-term observations of interannual and decadal variation of sea surface temperature (SST) in the Taiwan Strait (TS) were studied for the period 1870-2018; the climatology data were obtained from the Met Office Hadley Centre, UK. In the study period, the highest annual mean and lowest SST observed were 25.3 degrees C in 1998 and 22.4 degrees C in 1919, respectively. Six distinct regimes were identified. The first regime of fairly stable or slightly cooling SST lasted through the 1920s. The two regime shifts of 1919-1945 and 1976-1977 to 1998 led to the two fast warming trends of 2.0 degrees C in 26 years, from 22.5 degrees C in 1919 up to 24.5 degrees C in 1945, and of 2.4 degrees C in 22 years, from 22.9 degrees C in 1977 up to 25.3 degrees C in 1998, respectively. Another two regime shifts initiated in 1945 (1945-1976) and 1998-1999 (1998-2011) that led to 1.6 degrees C and 1.0 degrees C cooling, respectively. A recent and fast warming trend with 0.63 degrees C/decade suggested that the warming hiatus from 1998 to 2011 faded away since 2012. The spatial distribution of climate trends through the decades across the TS revealed a strong spatial gradient along the Strait. In the north (southern East China Sea), the magnitude and rate of the overall SST warming between 1870 and 2018 were approximately 1.5 times than those in the south (northern South China Sea).