Sea-Level Variability in the Arabian Gulf in Comparison with Global Oceans

Abstract

The availability of nearly three decades of sea-level estimates from satellite altimetry, for the period from 1993 to the present, is exploited for understanding the climatology of sea level and its long-term variability in the Arabian Gulf (also known as the Persian Gulf) in comparison with global oceans. The Arabian Gulf is characterized by a lower sea level from February to May and a higher sea level from September to December, with a maximum in November and a minimum in April. The variability of sea level in the Arabian Gulf is significantly different and nearly opposite to the pattern of sea-level changes in the adjacent marginal basin, the Red Sea. The analysis of low-passed sea level using the empirical orthogonal function and principal component analysis showed that the first mode of variability explains 87.9% of the long-term variability and the second mode explains nearly half of the remaining variability (5.6%). The linear long-term trends in sea level are 2.58 mm/year for the Northern Arabian Gulf and 3.14 mm/year for its southern part, with an average of 2.92 mm/year for the entire Gulf. The analysis of sea level in the Arabian Sea showed a faster rate of sea level rise in the post-2000 period. The long-term linear trend for the post-2000 period in the Northern Arabian Gulf is 4.06 mm/year, and in the southern Gulf it is 4.44 mm/year, with an average trend of 4.29 mm/year. Under the RCP2.6, RCP4.5, and RCP8.5 scenarios, the numerical projections show an expected rise in sea level in the Arabian Gulf by 8.1, 1.3, and 6.8 cm by 2050, and by 16.9, 17.7, 39.1 cm, respectively by the end of the 21st century.