An analysis of Arabian Gulf monthly mean sea level

Arabian Gulf monthly mean sea level variations over a period of 11 years (1980–1990) are examined by spectral and regression analyses. The mean sea level is higher in summer and lower in winter with the range of 26 cm. About 80% of the monthly mean sea level variance can be related to seasonal changes. The seasonal variation of mean sea level is approximated by the sum of an annual and semi-annual component. The amplitude of the annual component is 11.3 cm while that of the semi-annual is about 2.5 cm. The sea level responds to atmospheric pressure as a near perfect inverse barometer. The results of regression analysis show that atmospheric pressure changes can explain about 75% of the variance of the seasonal signal. The remaining 25% of the seasonal signal is found to be due to seasonal changes in density. Regression of sea-level on time reveals the presence of a rising trend of 2.3 cm over the 11 year study period.