|Abstract Submission No.
|Title of Abstract
|Representation of Mean State and Variability of Dynamic Sea Level and its Projections for the Indian Ocean in CMIP6 Models
|Sajidh CK*, Abhisek Chatterjee
|Indian National Centre for Ocean Information Services
|Indian national centre for ocean information services
Hyderabad, Telangana, India
|The Indian Ocean (IO) coastline which houses a large population from the continents of Africa, Asia and Australia is vulnerable to a plethora of climatic hazards that are brought on by sea-level rise. The global mean sea level has risen at a rate of ~3.6 mm/yr over the last two decades and is projected to increase by more than 1m by the end of this century. A thorough assessment of the dynamics of the regional sea-level change is vital for effective policymaking to mitigate natural calamities associated with the rising sea levels. We use a suit of 27 models from phase six of the coupled model intercomparison project (CMIP6) simulations to study their representation of dynamic sea level (DSL) and the factors that influence DSL variability in the basin. We show that the multi-model mean DSL exhibits a good correlation with observation with few notable biases consistent across the models. There is a positive bias in the DSL across the basin with a west to east gradient and a pronounced bias in the Antactic circumploar current region. In the case of variability, most of the models underestimate the variability across the basin except the eastern equatorial IO. The poor representation of the equatorial winds in most models produces an Indian Ocean Dipole (IOD) like bias and results in the misrepresentation of climatic modes. Our analysis suggests that a finer horizontal resolution of the ocean component alone cannot guarantee a better representation of the DSL but requires proper representation of wind fields as well. A subset of best performing models among the ensemble is selected to have a more representative estimate of DSL change in the Indian Ocean. The Arabian Sea is expected to experience higher sea level rise (~35 cm), compared to the Bay of Bengal and the southern tropical Indian Ocean under a high emission scenario by the end of 2100. This research aims to gain better insights on the DSL evolution and its future projections in the Indian Ocean and to investigate the model deficiencies associated with the same.
|Dynamic Sea Level, Climate modes, Indian Ocean dipole, Global warming, Emission scenarios
|Date Of Birth