01-05 December 2025
INCOIS, Hyderabad, India.
| Abstract Submission No. | ABS-06-0080 |
| Title of Abstract | Decadal variability in ocean-atmospheric interaction and its implications on primary productivity in the central Arabian Sea |
| Authors | Natasha Majumder*, Sreejith K S, Medhavi Pandey, Haimanti Biswas |
| Organisation | CSIR-National INstitute of Oceanography |
| Address | Donapaula Goa, Goa, India Pincode: 403004 E-mail: natasha.majumder@gmail.com |
| Country | India |
| Presentation | Oral |
| Abstract | The Arabian Sea, one of the oceanic regions with the highest primary productivity, which varies annually influenced by semi-annual reversal of the monsoon winds, affecting its physical and biogeochemical properties. This basin also receives a significant amount of atmospheric dust that supports phytoplankton growth. The Arabian Sea is warming faster than any other ocean, and its impacts are not well understood. Long-term ocean observation is crucial for monitoring these changes, as they may impact ecosystem functioning and carbon cycling. This study uses high-resolution satellite data on Chl-a, winds, SST, AOD, and dust deposition, combined with reanalysis mixed-layer depth estimates, to identify factors that influence surface water productivity and upper-ocean processes. This study analyzes twenty years of satellite data considering aerosol optical depth (AOD), Chl-a concentration, wind speed (WS), and sea surface temperature (SST) during summer and winter monsoons covering the area between 62°E to 66°E and 18°N to 22°N for Northern Arabian Sea (NAS) and 62°E to 66°E and 9°N to 15°N for Southern Arabian Sea (SAS). The results revealed a significantly higher spatial variability in Chl-a, SST, and AOD in the NAS compared to the SAS. In NAS, Chl-a shows average values > 1 mg m-3, and in the SAS, it was < 0.5 mg m-3. The findings also show SST trends increase over decades in summer without any significant trends in winter. Conversely, AOD exhibits a notable increase in winter, but not in summer. Other factors, such as wind velocity and upwelling intensity, are also explored to understand the interplay between all these factors. Despite higher SSTs over the past two decades, Chl-a concentration has not changed significantly. We hypothesize that increased SST may reduce nutrient supply due to enhanced stratification, although atmospheric deposition could help compensate for some nutrient deficits. Further analyses are in progress. |
| Are you part of IIOE-2 endorsed project | no |
| Keywords | Productivity; Temperature; Aerosol optical depth; Atmospheric forcing; North Indian Ocean |
| For Awards | no |