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| Abstract Submission No. | ABS-2022-04-0312 |
| Title of Abstract | Mixed Layer heat budget in the North Eastern Arabian Sea during winter and spring and relative contribution of diapycnal heat flux |
| Authors | Jofia Joseph*, Ashin Kuriakose, Girishkumar M.S, Sureshkumar N, Sherin V Raju, Suprit Kumar, V P Thangaparakash, S.Shivaprasad, E. Pattabhi Ram Rao, S. S. C. Shenoi |
| Organisation | Incois |
| Address | Incois, pragathinagar Hyderabad, Telangana, India Pincode: 500090 Mobile: 8129651858 E-mail: jofiajoseph1992@gmail.com |
| Country | India |
| Presentation | Oral |
| Abstract | Sea surface temperatures (SSTs) simulated in the coupled model consistently colder (~-1 to -4°C) than observation in the northern Arabian Sea (AS) during winter and spring. These biases significantly weaken the seasonal and extended summer monsoon prediction skills and climate change projections' reliability in this region. To understand the relative contribution of diapycnal heat flux compared to other terms in the mixed layer (ML) temperature (MLT) budget during these two seasons, we use time series of vertical profiles of microstructure shear measurements collected in the northeastern AS (NEAS) at 18.4°N and 67.4°E during 10-17 January 2019 (W19) and 7-21 May 2019 (S19). It is found that the vertical processes term and net surface heat flux together determine the bulk of MLT tendency during S19 and W19, and the contribution of the horizontal advection and diapycnal term is relatively smaller. It is also found that consistent with the higher mean value of eddy diffusivity (Kρ) at the base of the ML in S19 (1.6x10-2 m2 s-1) than W19 (2.5x10-5 m2 s-1), mean diapycnal heat flux (Jh) was higher in the former case (~-2.5 Wm-2) than latter (-200 Wm-2). Our analysis exhibits that Kρ and Jh values estimated using different Kρ-Ri based interior ocean parametrization schemes at the ML base in the NEAS overestimate with respect to observation, though ⿿Peters et al. (1988) low-shear⿿ outperforms other schemes. The alleged role of overestimation of Kρ and Jh in parameterization schemes on model simulation of cold SST bias in the AS is also discussed. |