INCOIS ‘SAM’ study to understand fair weather patterns on seas for maritime activities

INCOIS scientists discover SAM climate pattern shapes sea conditions across Indian Ocean, aiding coastal planning, resource mgmt & disaster prep. Study findings can improve wave predictions & identify fair weather windows, benefitting fisherfolk & blue economy stakeholders. 40-yr data analysed to find positive SAM phase causes warm sea surface temp & strong winds, increasing wave activity in Indian Ocean. Negative SAM phase reduces wave heights in Arabian Sea, allowing fair sea state windows to be identified for oil & shipping industries.

Indian National Centre for Ocean Information Services (INCOIS), under the Ministry of Earth Sciences (MoES), has discovered that the Southern Annular Mode (SAM), an important climate pattern, plays a pivotal role in shaping the sea conditions across the Indian Ocean.

Scientists, who have been studying the SAM climate pattern and trying to understand how it shapes the wave patterns over extended time frames, state that it could help the country in better coastal planning, resource management and also in disaster preparedness.

Their study’s findings can also contribute to advancing the accuracy of wave predictions and can help identifying fair weather windows, thus benefitting the fisherfolk community and blue economy stake holders such as shipping, maritime boards and oil industry for their multi-million dollars worth operations at sea.

INCOIS scientists said that it is important to study ocean surface waves as they play a crucial role in shaping the coastal processes, and influencing numerous aspects of society, including shoreline erosion, sediment transport, coastal engineering and recreational activities.

The scientific team used the 40-year data (1979 to 2018) from the European Centre for Medium-Range Weather Forecast to analyse seven parameters such as wave height, wave period and wind speed for the study.

They found that during a positive SAM phase, a cyclic pattern of warm sea surface temperature anomalies was seen, and strong winds caused increased wave activity in Indian Ocean. They also found a new swell generation region along the east African coast, which caused an increase in wave height in the Arabian Sea.

On the other hand, during a negative SAM phase, the eastern tropical southern Indian Ocean becomes the main region for generating swells, resulting in reduced wave heights in the Arabian Sea.