01-05 December 2025
INCOIS, Hyderabad, India.
| Abstract Submission No. | ABS-04-0240 |
| Title of Abstract | Impact of the Atlantic Zonal Mode on ocean surface waves in the tropical Indo-West Pacific during boreal summer |
| Authors | Vijay Pottapinjara*, Meenakshi Sreejith, P G Remya, Sudheer Joesph, T M Balakrishnan Nair |
| Organisation | Indian National Centre for Ocean Information Services (INCOIS) |
| Address | Indian National Centre for Ocean Information Services Hyderabad, Telangana, India Pincode: 500090 E-mail: vijay.p@incois.gov.in |
| Country | India |
| Presentation | Oral |
| Abstract | Ocean surface waves, which are gravity waves primarily driven by surface winds, significantly influence air-sea interactions, coastal ecology, and marine operations. Tropical climate variability is shaped by ocean⿿atmosphere coupled modes such as the El Niño⿿Southern Oscillation (ENSO), and the Indian Ocean Dipole (IOD), which also influence ocean surface waves through changes in surface winds. This study examines the impact of the Atlantic Zonal Mode (AZM), a less-studied climate driver, on the interannual variability of ocean surface waves in the tropical Indo⿿West Pacific. A warm AZM induces surface wind anomalies that oppose the climatological winds. As a result, it reduces the wind sea by 0.2⿿0.3 m in the South China Sea (SCS), and by 0.1⿿0.2 m each in the Bay of Bengal (BoB) and the Philippine Sea (PS), causing an apparent domination of Southern Ocean swells in the Arabian Sea. It is substantiated by consistent changes in the mean wave period and energy flux into waves. A warm AZM can favour marine operations in the BoB, SCS, and PS. On the contrary, a cold AZM is not observed to cause any statistically significant change in the wave activity during the analysis period, highlighting an asymmetric impact of the AZM, the reasons for which require further investigation using wave model sensitivity experiments. Given the future projections of a weakening Atlantic cold tongue under global warming, effects of warm AZM events may intensify, potentially leading to further reductions in tropical Indo⿿West Pacific wave activity. These findings highlight the importance of incorporating AZM impacts in wave climate assessments. |
| Are you part of IIOE-2 endorsed project | no |
| Keywords | Atlantic Zonal Mode, Ocean waves, Marine Operations, Indian Ocean, South China Sea |
| For Awards | yes |
| Date Of Birth | 23-04-1987 |
| ECSN Registration Number | IIOE2-ECSN-0151 |