Study On Global Sea Level Change Characteristics Based On Multi-source Data

The rate of sea level change and its spatial distribution characteristics have always been one of the most concerned issues.Monitoring sea level rise and studying the correlation between global sea level changes and sea surface temperature,salinity,and melting glaciers are of great significance.With the continuous development of satellite altimeter,the use of satellite altimeter data to study sea level changes has become the main observation method of sea level research.This article uses the global ocean gridding SSALTO/DUACS sea level L4 product from 1993-2019,which is a combination of two satellites,the 2002-2019 TELLUS_GRAC-GRFO_MASCON_CRI_GRID_RL06_V2 global gravity anomaly dataset,and the 2003-2018 global ocean temperature and salinity.The monthly average data set in the product(MULTIOBS_GLO_PHY_REP₀15₀02)calculates the global sea level outliers,sea water equivalent water height and steric sea level height respectively,and uses linear regression analysis,power spectrum analysis,EOF analysis,etc.to change the global ocean sea level The trend,periodicity,spatial distribution,etc.were studied.The main findings are as follows:The sea level rise rate from 1993 to 2019 calculated based on the global ocean grid products is 2.98mm/a,and 97.89%of the world's sea level is rising.After power spectrum analysis and EOF analysis,the global sea level change has a significant one year Period,and mainly affected by seasonal changes such as temperature and wind stress,heat flux,precipitation,ENSO and other factors.Based on the GRACE satellite global gravity satellite data set,the global oceanic mass rise rate from 2002 to 2019 is 2.14 mm/a,which is the main reason for the sea level change.The power spectrum analysis and EOF analysis show that the global oceanic mass change has 1 year Due to the influence of the ocean positive pressure adjustment process,there is no obvious difference in the oceanic mass between the northern and southern hemispheres.The fitting value of the global steric sea level rise rate calculated from 2003-2018 based on reanalysis products such as global ocean temperature and salinity is 0.57 mm/a.Through the power spectrum analysis and EOF analysis,the global steric sea level periodic signal is relatively messy.The first three spatial modes and the power spectrum are all related to the spatial mode and power spectrum of the total sea level change.As a whole,global sea level changes are accelerating,mainly affected by changes in oceanic mass and seawater volume.Oceanic mass changes have contributed about 70.4%of global sea level growth,mainly affecting the rise of sea level changes Rate,and the difference in the spatial distribution of global steric sea level due to uneven distribution of heat flux and salinity directly affects the spatial distribution characteristics of global sea level changes.