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| Abstract Submission No. | ABS-2022-04-0303 |
| Title of Abstract | Observed diurnal air-sea fluxes variability in the Northern Indian Ocean using moored-buoy data |
| Authors | ATHULYA K*, SUPRIT KUMAR, JVS RAJU |
| Organisation | INDIAN NATIONAL CENTRE FOR OCEAN INFORMATION SERVICES |
| Address | 101, srinivasa residency, INCOIS road Hyderabad, Telangana, India Pincode: 500090 Mobile: 9809857377 E-mail: athulyakaladharan3285@gmail.com |
| Country | India |
| Presentation | Poster |
| Abstract | The northern Indian Ocean (NIO) is a region of extreme air-sea interactions impacting both regional and global weather and climate. Quantifying these air-sea interactions through surface fluxes (heat, freshwater, and momentum fluxes) at appropriate scales is a historically challenging problem in the NIO owing to the lack of data. In recent years, there are efforts to install reference flux stations in the NIO to measure the fluxes directly. However, there are operational moored-buoys already set up in the region which provide high-resolution time-series observations of surface meteorological and upper-ocean variables. In this study, we have utilized one such buoy network called OMNI (Ocean Moored buoy Network for the Northern Indian Ocean) to estimate hourly surface-fluxes (heat and momentum) and related uncertainties to document their variability. Hourly observations from three OMNI buoys (BD08, BD09 (in the northern Bay of Bengal; ~89°E, 18°N), and BD12 (in the Andaman Sea; 94°E, 10°N)) were used to derive the hourly fluxes using COARE V3.0 algorithm. We have estimated the impact of ignoring the diurnal variability in estimating the daily fluxes. Latent heat flux exhibited diurnal variability with a maximum of about 30 W/m 2 (mean: 107 W/m 2 ) and sensible heat flux of about 8 W/m 2 (mean: 5.73 W/m 2 ) which would probably affect the net heat flux. Most of this variability could be explained by the warm layer and cool skin effects, as we obtained comparable estimates of diurnal variability when we switched these effects off and on, in the COARE V3.0 algorithm. Strong seasonality was also observed, with maximum SHF and LHF diurnal variability occurring in the spring season (March-May) as compared to peak monsoon season (June⿿August). Since diurnal variability is resultant of the competing effect of stabilizing solar heat influx and destabilizing wind stress, the seasonality in the controlling factors may also evoke similar responses in related processes. High-frequency air-sea flux data is sparse in the northern Indian Ocean, which may affect the predictability of various climate modes. Our primary objective is to address this lacuna and enhance the accurate determination of fluxes which will enable us with better numerical weather prediction and climate research in the near future. |