中国沿海和近海海平面上升预测

本文利用验潮站观测和卫星高度计数据，以及基于筛选的CMIP6的10个模拟性能较好的地球系统模式结果，对中国海平面的长期变化趋势，以及未来上升幅度进行了分析和预测。结果显示：（1）1960?2021年，中国沿海海平面呈加速上升趋势，上升速率为2.5 mm/a，加速度为0.06 mm/a²；1993?2021年上升速率为4.0 mm/a，高于全球同期3.3 mm/a的上升值。（2）1980?2021年，渤、黄海，东海和南海沿海海平面上升速率分别为3.5 mm/a、3.3 mm/a和3.6 mm/a，渤、黄海和南海沿海海平面上升速率较快，东海偏慢；渤、黄海沿海海平面在20世纪60?70年代上升较慢，80年代之后上升加快。（3）在中等情景（SSP2-4.5）和高情景（SSP5-8.5）下，2050年中国近海海平面将上升0.22 m（0.19～0.28 m）和0.24 m（0.21～0.33 m）；到2100年，中国近海海平面将上升0.59 m（0.47～0.80 m）和0.83 m（0.64～1.09 m）。（4）2021?2040年，统计预测的海平面上升中值略接近数值模式低、中和高情景预测值。2041?2060年，数值模式低、中和高情景预测值均介于统计预测的中值和高值之间。2081?2100年，统计预测的海平面上升高值与数值模式中情景预测值接近，绝对偏差为0.017 m，相对偏差为3.4%。（5）高情景下，2100年现有100年一遇的极端高海面将变为不足10年一遇，其中超过50%的站点将变为不足两年一遇，沿海防护工程等基础设施的防御能力降低，复合型滨海城市洪涝等灾害事件的风险增加。

Sea level rise projection in China’s coastal and offshore areas

Using tide gauge observation, satellite altimeter data, and the result of 10 CMIP6 Earth System Models with good simulation performance, the long-term trend of sea level change in China, and predicts the range of sea level rise in the future are analyzed in this study. The results show that: (1) from 1960 to 2021, the sea level in China’s coastal areas showed an accelerated rising trend, with a rise rate of 2.5 mm/a and an acceleration of 0.06 mm/a2. From 1993 to 2021, the rise rate was 4.0 mm/a, higher than the global rate of 3.3 mm/a in the same period. (2) From 1980 to 2021, the sea level rise rates of the Bohai Sea and the Yellow Sea, the East China Sea and the South China Sea were 3.5 mm/a, 3.3 mm/a and 3.6 mm/a, respectively. The sea level rise rates of the Bohai Sea and the Yellow Sea, the South China Sea were relatively fast, while the sea level rise rates of East China Sea was slow. The coastal sea level rose slowly from 1960s to 1970s, and accelerated after 1980s in the Bohai Sea and the Yellow Sea. (3) Under the medium (SSP2-4.5) and high (SSP5-8.5) scenarios, China’s offshore sea level will rise by 0.22 m (0.19?0.28 m) and 0.24 m (0.21?0.33 m) respectively in 2050, and will rise by 0.59 m (0.47?0.80 m) and 0.83 m (0.64?1.09 m) respectively in 2100. (4) During 2021?2040, the median value of sea level rise predicted by statistics is close to the predicted value under the low, medium and high scenarios of the numerical model. During 2041?2060, the predicted values of the low, medium and high scenarios of the numerical model are between the middle and high values of the statistical prediction. During 2081?2100, the high value of sea level rise predicted by statistics is close to that predicted by the medium scenario of the numerical model, the absolute deviation is 0.017 m, and the relative deviation is 3.4%. (5) Under the high scenario, the existing once-in-a-century extreme high sea level in 2100 will become less than 10 year return period, in which more than 50% of the stations will become less than 2 year return period, the defense capacity of coastal protection works and other infrastructure will be reduced, and the risk of flood and other disaster events in complex coastal cities will increase.