Sea level rise assessment in the Persian Gulf and Arabian Sea using geodetic observations

Abstract

Sea Level Rise (SLR) due to climate change is a significant concern, especially for coastal areas, posing risks to infrastructure and inhabitants. The Persian Gulf (PG) and the Arabian Sea (AS) are two vital regions, recognized for their strategic geopolitical importance, underscoring the need to evaluate sea level changes thoroughly. This study aims to quantify and analyze SLR and identify its spatiotemporal variability across the PG and AS using trend analysis and a tensor-based approach, employing tide gauge records and satellite altimetry observations. Monthly Mean Sea Level (MSL) measurements from 14 tide gauge stations in the PG and AS, from 1993 to 2021, were examined and exhibited an upward trend ranging from 0 to 100 mm per decade (mm/dec). Satellite altimetry data, presented as mean Sea Level Anomaly (SLA) across the area and gridded SLA observations from 1993 to 2022, were analyzed and it revealed an ascending trend of approximately 46 and 39 mm/dec for the PG and AS, with the notable rise in the mean SLA trend beginning around 2005. To enhance the gridded SLA data analysis, a 3D tensor was constructed, with two axes representing latitude and longitude, and the third axis representing time. A final trend map was derived from the 3D SLA tensor to illustrate the SLA trends across different locations within these regions. The SLA trend varied from 15 to 55 mm/dec, with eastern AS exhibiting the highest, while the lowest trends occurred west of AS. The coastlines generally experienced higher SLA trends compared to the nearby deep ocean. These findings underscore the growing vulnerability of some coastal zones in the PG and AS to rising sea levels, highlighting the need for adaptive coastal management strategies. The trend map derived from the SLA tensor provides valuable insights for identifying the most vulnerable zones.