Sea Level Variability around the Java Sea (study Area: Northern of Gresik and Surabaya) using Cryosat-2 Altimeter

Sea level rise is one of the issues that are on the highlight today. Seawater that is in direct contact with the coastal area makes the region vulnerable to the environment. The Java Sea in Indonesia with a wide enough coverage will have many impacts on the coastal areas if there is an increase in sea level. For these observations, a sea-level anomaly (SLA) is calculated to understand sea level and its changes over time. SLA calculations use data from Cryosat-2 Satellite. Cryosat-2 is an altimetry satellite that was designed for the ice sheet observation mission and oceanography observation missions. This altimetry satellite has an excellent level of accuracy even though it does not have a microwave radiometer. This research is expected to know sea level variability of the Java Sea surface from 2011 to 2019. Obtained based on linear regression of the Cryosat-2 SLA trend, the Java Sea has decreased by 27.9746 mm at a rate of -3.55 mm/year. It is caused by the phenomenon of El-Nino Southern Oscillation (correlation coefficient of the SLA and MEI detrended indicating indicates a strong but not unidirectional correlation. The higher the MEI index, the lower the SLA value will be in the Java Sea, a vice versa, and MEI detrended, indicating a strong but not unidirectional correlation. The higher the MEI index, the lower the SLA value will be in the Java Sea, and vice versa.