Study On Sea Level Changes Of The East China Sea For The 21st Century

In this paper,we use IPCC AR5 multi-model data to study the spatial and temporal characteristics of sea level change and its contributors in East China Sea(ECS)under the multi emission scenarios in the 21 st century.At the same time,we use the ocean circulation model(ROMS)to carry out dynamic downscaling simulation to obtain the high-resolution spatial distribution of sea level rise in East China Sea.It is found that by the end of the 21 st century(2090-2100 mean compared with 2010-2020 mean),the regional average sea level of the ECS will rise 344 [178-520] mm,433 [238-648] mm and 630 [358-949] mm under the scenario of RCP2.6,RCP4.5 and RCP8.5 respectively,which is the same as the global sea level rise.On the regional distribution of sea-level rise in ECS,the rising range of each scenario is relatively large in the southern sea area,but relatively small in the northern sea area.The contribution of Ocean(ocn,including ocean dynamic and thermal changes),land ice(including land glaciers and Antarctic / Greenland ice sheet changes)and other factors(including groundwater and glacier equilibrium adjustment)to sea level rise are further calculated.It is found that by the end of the 21 st century,the contribution of ocn and land ice to the regional mean sea level rise in the ECS under the RCP8.5 scenario is equivalent,while under the RCP2.6 and RCP4.5 scenarios the contribution of land ice is slightly higher than that of ocn,and the contribution of other factors to the ECS is almost zero.The spatial distribution characteristics of land ice and ocn are similar to that of the total sea level rise,and the largest spatial distribution difference is under the high emission scenario.In the 21 st century,the rise of sea level in Shanghai is less than that in the ECS,and land ice contributes to largest proportion reaching to 59%.It is difficult to predict the spatial distribution of sea level rise in ECS due to the low resolution of the coupled model.We use the dynamic downscaling method with the model — ROMS to simulate the ocn part above,and focus on the spatial distribution of sea level rise.Taking SSP5-8.5(CMIP6)as an example,the forcing field comes from the BCC-CSM2-MR global coupling model.The significant spatial distribution characteristics of the dynamic downscaling simulation are as follows: the sea level rise of the Kuroshio basin is large,and that of the ECS is small;the sea level rise of the central sea area of the Yellow Sea and the East China Sea is higher than that of the coastal areas on the east and west sides;the distribution of the sea level coastlines of the eastern Yellow Sea and the East China Sea is relatively low in the coasts of Shanghai and Zhejiang.Further analysis shows that the contribution of local thermosteric in the East China Sea is small,and its spatial form is mainly determined by the distribution of water depth,which indicates that the sea level rise in the ECS is mainly determined by the dynamic and thermal changes of the adjacent ocean.