Influence of Tropical Cyclone Biparjoy on Arabian Sea Mini Warm Pool: Insights from EKAMSAT Pilot Cruise

The northern Indian Ocean is characterized by complex interactions and variability of the atmospheric and oceanic flow regimes. On an annual basis, a phenomenon known as the Southeastern Arabian Sea Mini Warm Pool (MWP) arises, displaying the world's highest recorded sea surface temperatures (>30°C) during the period in which it appears. The MWP develops from March to May, and then dissipates quickly with the onset of the Summer Indian Monsoon. The EKAMSAT research program completed its pilot cruise in the eastern Arabian Sea aboard the R/V Roger Revelle from June 11 to June 24, 2023, during the dissolution phase of MWP following the onset of the Summer Indian Monsoon on June 8, 2023. Tropical Cyclone Biparjoy (TCB) traversed northwards over the Arabian Sea from June 6 to June 16, 2023 in the wake of which in-situ observations were conducted during the initial phase of the cruise. Preliminary findings suggest that TCB had a significant influence during the onset phase of the Summer Indian Monsoon as well as dissolution of MWP. Changes in the sea surface temperature, oceanic mixing, oceanic planetary waves and lower atmospheric dynamics appear to influence the size of MWP, its position, and intensity. The present study focuses on air-sea interaction observations made using flux tower, sea snake, and a Present Weather Detector (PWD-22) aboard the R/V and their interpretation using atmosphere/ocean synoptic state mapped by high frequency radiosonde launches, a ceilometer, satellite and reanalysis data. In particular, the study will address how tropical cyclones, such as TCB, impact the MWP and its role in the onset of the Summer Indian Monsoon.