Salt Budget in the Arabian Gulf and Effects of Water Desalination

Due to the excess evaporation, much greater than precipitation and riverine inflow, the Arabian Gulf is a hypersaline environment. The net evaporation drives an inverse-estuary circulation, with import of fresher surface waters and export of saltier waters to the Indian Ocean in the deeper layers. Understanding the structure and variability of this exchanging mechanism is highly relevant since any imbalance could lead to salinity trends in the Gulf, with possible impacts on the hydrographic and environmental properties, both locally and in the northern regions of the Indian Ocean. Recent studies suggest that the Arabian Sea might be going through changes. Published analyses of daily optimum interpolated sea surface temperature anomaly (DOISSTA) distributed by the USA National Oceanic and Atmospheric Administration (NOAA) report a gradually increasing trend in DOISSTA in the Arabian Gulf and the Gulf of Oman since the 1980’s. Another investigation, based on an autoregressive integrated moving average (ARIMA) model, suggests that the averaged SST in the Arabian Gulf has increased in 0.57^oC from 1950 to 2010, with a more pronounced trend in the last two decades. While these changes are likely to be mainly driven by the global warming, a relevant question can be asked on the contribution of the intense and increasing water desalination activity in the Arabian Gulf. This paper will discuss the present day salt budget and results of twin experiments, in which the anthropogenic contribution to the salt budget in the Gulf is turned on and off.