Detection of Sea Level Rise Monitored from Surabaya Tidal Station Data from 2013 to 2021

Sea level rise is a certainty because of changes in human life that use machines so that it produces pollution that increases global warming which can make the polar ice caps melt so that the volume of sea water increases. The impact of sea level rise includes changes in coastline, tidal flooding and other impacts that can reduce the quality of life of the community. Surabaya is the second big city on the island of Java after Jakarta which has a population of 2,878,314 people based on the results of the 2020 BPS population census. Of course, this automatically makes the city nicknamed the city of heroes an important city in Indonesia. Therefore, the Geospatial Information Agency as one of the agencies providing tidal data has placed one of its observation stations in the city of Surabaya, located in Ujung Village, Semamir District, Surabaya City, at coordinates 07° 12’ 0.1” South Latitude 112° 44’ 26.1 ” East longitude. The results of data processing using the smallest smoothing method resulted in the LAT tidal datum values, namely -0.636 m, MSL 1.131 m and HAT 2.850 m. The tidal type at the Surabaya tidal station is a mixed mixed tide type which tends to double daily, with an average tidal harmonic constant value of O1 = 0.265 m, S2 = 0.230 m, K1 = 0.476 m, and M2 = 0.377 m. The most dominant tidal harmonic constant is M2, and the lowest harmonic constant is M4 while sea level rise in the city of Surabaya based on the analysis of tidal observation data for 9 (nine) years is 0.199 mm/month.