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Sea surface temperature (around Japan)

Updated on 10 Mar. 2021
Japan Meteorological Agency

The annual average sea surface temperature (SST) around Japan has risen by +1.16°C over the last 100 years, which exceeds the corresponding figure for the global ocean (+0.56°C) and is similar to that for surface air temperature in Japan (+1.26°C). The rates of increase in Areas N3, E1, S2, W1, W2 and W3 (see the table below) are also similar to those for surface air temperature in Japan, while those for Areas E2, E3, S1, S3 and W4 are lower and that for Area N2 is higher.

Rates of area averaged SST increase around Japan
Area
number
Area name
N1Northeastern part of the Sea of Japan
N2Central part of the Sea of Japan
N3Southwestern part of the Sea of Japan
E1Sea off Kushiro
E2Sea off Sanriku
E3Eastern part of the sea off Kanto
S1Southern part of the sea off Kanto
S2Sea off Shikoku and Tokai
S3East of Okinawa
W1Yellow Sea
W2Northern part of the East China Sea
W3Southern part of the East China Sea
W4Sea around the Sakishima Islands

Increase rates of area-averaged annual mean SSTs around Japan from 1900 to 2019 (°C per century)
Areas with no symbol have statistically significant trend at the confidence levels of 99 %. Areas marked with [#] are those where no discernible trend is seen due to large SST variability factors such as decadal oscillation.

Commentary

The annual average SST around Japan has risen by +1.14°C over the last 100 years, which exceeds the corresponding figure for the global ocean and the North Pacific (+0.55 and +0.53°C, respectively) and is similar to that for surface air temperature in Japan (+1.24°C). The rates of increase in regional annual mean SSTs in Areas N3, E1, S2, W1, W2 and W3 (see the table above) are similar to those for surface air temperature in Japan, while those for Areas E2, E3, S1, S3 and W4 are lower and that for Area N2 is higher. The SST in Area N1 exhibits no statistical long-term trend.

According to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR5) Working Group I, warming of the climate system is unequivocal and it is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century. As detailed in the IPCC AR5 Working Group I Report, observed changes in surface temperatures during the period from 1901 to 2012 show significant variations among regions. The inland of Asia has exhibited particularly marked warming. The global warming is considered to have contributed to the SST increase around Japan. In addition to that, natural fluctuations such as Pacific Decadal Oscillation (PDO) and variations in the Kuroshio Extension are also thought to have contributed to the rising SST trend observed around Japan.

Data file download

All text file sizes are about 5KB.

Area
number
Area nameData file
N1Northeastern part of the Sea of Japan[text file]
N2Central part of the Sea of Japan[text file]
N3Southwestern part of the Sea of Japan[text file]
E1Sea off Kushiro[text file]
E2Sea off Sanriku[text file]
E3Eastern part of the sea off Kanto[text file]
S1Southern part of the sea off Kanto[text file]
S2Sea off Shikoku and Tokai[text file]
S3East of Okinawa[text file]
W1Yellow Sea[text file]
W2Northern part of the East China Sea[text file]
W3Southern part of the East China Sea[text file]
W4Sea around the Sakishima Islands[text file]