East-west Variability of Sea Level in the Red Sea

Cheriyeri Poyil Abdulla

The sea level changes and associated physical processes are not explored well compared to other parts of the world. In the present study, the sea level variability in the Red Sea is investigated with the help of more than two and half decades of remote sensing observations from satellite altimetry. Considering the east–west difference in sea level, the study revealed the presence of a persistent east–west pattern which is visible every year. This east–west (EW) difference is positive during winter when a higher sea level is observed on the eastern coast of the Red Sea and negative during summer when a relatively lower sea level is observed in the same region. May and October are transition months, with a variable pattern in the change in sea levels. The EW difference in the southern Red Sea is slightly larger than that in the northern part during summer, by an average of 0.2 cm. For both the northern and southern Red Seas, wavelet analysis reveals a large annual cycle as well as other signals of lesser amplitude. EOF1 correlates to 98 percent of overall variability, EOF2 to 1.3 percent, and EOF3 to 0.4 percent, according to Empirical Orthogonal Function (EOF) analysis. ENSO has a strong remote reaction to EW differences, whereas the Indian Ocean Dipole (IOD) and North Atlantic Oscillation (NAO) have minor responses. The occurrence of this EW differential phenomena is caused by three physical mechanisms: wind, buoyancy, and the polarity of eddies.