Why is mean sea level along the Indian coast higher in the Bay of Bengal than in the Arabian Sea?

Levelling observations conducted during the Great Trigonometrical Survey of India (1858-1909) and subsequent observations showed that mean sea level a long the coast of India is higher in the Bay of Bengal than in the Arabian Sea, the difference in sea level between Vishakhapatnam and Mumbai (Bombay) being about 30 cm. Using simulations with a 1 1/2-layer reduced-gravity mo del, we attribute this to the mean, large-scale wind-forced circulation (si milar to 60%) and the alongshore gradient in salinity (similar to 40%). The former (latter) is a consequence of the distribution of wind stress (rainf all) because of the monsoon.