Variability of sea surface topography in coastal area (study case: Indonesia)

Abstract

The deviation of the sea surface from the geoid reference surface is known as the Sea Surafce Topography (SST). SST is caused by several physical phenomena such as ocean wave, tides, current and atmospheric pressure loading, and the main application of SST is to determine ocean circulation. To get the SST, we use Sea Surface Height (SSH) and Mean Dynamic Topography (MDT) based on 30 years of sea-level data derived from multi-mission of satellite Altimetry and geoid height (Undulation) from Global Gravitation Model EGM-2008. Indonesia is an archipelagic country in the equatorial region that lies between Indian and Pacific oceans. Its geographical setting will affect variability of Sea Surface Topography (SST) in the Indonesian Sea. The anomaly from SST is one of the oceanic parameters that play a crucial role in the ocean dynamic and its possible hazards. We found that the characteristics differ considerably from one place to another, depending on the bathymetric depth and type of sea. The mean SSH varies from about 40 meters and rises to the east up to a height of 80 meters. Likewise, the MDT value increased from 0.5 meters to the east to a height of 1.2 meters. In closed, narrow and shallow seas, the long time-series of those surfaces are less sensitive to the effects of El Niño and La Niña as well as global sea level rise. On the other hand, global sea level rise significantly affects the characteristic of both surfaces over open and deep seas. We hope by using more spatially dense data from multi-mission satellite altimetry, we can see more detail about the local phenomena that influence SST. By studying the variability of SST from more than one cycle (18.6 years) it is expected that it can be used to understand the dynamics of the coastal area in Indonesia.

Utilization of Mean Dynamic Topography for GNSS-Leveling Applications (Case Study: Jakarta Area)

“…As mentioned above, this selection was made so that high-frequency anomaly values due to noise in coastal and island areas can be ignored, so that the process of interpolating and extrapolating MDT values towards the mainland can be carried out more smoothly. MDT analysis of Indonesian seas for the 1992-2018 timeframe provides a deviation of no more than ± 2 m according to theoretical values [11,12]. The MDT value shown in Figure 4A is divided into two parts.…”

Estimasi Sea Surface Topography Menggunakan Data Satelit Altimetri di Laut Indonesia Timur Periode 2016-2021

“…Fenomena ENSO itu ditandai dengan terjadinya anomali suhu permukaan laut di Samudera Pasifik. Dimana, saat El Nino ditandai dengan peningkatan suhu diatas suhu normal dan La Nina ditandai dengan penurunan suhu di bawah suhu normal (Safitri, 2015).…”

“…Hasil korelasi antara SST dengan indeks ENSO adalah negatif dan berintensitas tinggi yang dapat dilihat pada gambar 4.16 dan 4.17. Menurut (Safitri, 2015) ketika terjadi fenomena El Nino (Indeks MEI positif), menyebabkan tekanan atmosfer menjadi naik dan suhu permukaan laut menjadi turun di Samudera Pasifik bagian barat atau wilayah Indonesia. Hal tersebut berdampak pada penurunan nilai SST di Laut Indonesia Timur karena adanya kemarau berkepanjangan, penurunan jumlah curah hujan dan peningkatan temperatur udara.…”

Estimation of Sea Surface Topography Using Jason-3 Satellite Altimetry Across the Eastern Indonesian Seas in a period of 2016 to 2021

“…Strong water flows and large volumes of ITF can cause changes in the distribution of water masses in the Indonesian Sea. This can have an impact on increasing or decreasing sea level topography in the areas traversed by the ITF.Sea Surface Topography (SST) is the deviation of sea level from the geoid reference [3]. Tides, atmospheric pressure, temperature variations, and rainfall are the causes of SST [4].…”