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| Abstract Submission No. | ABS-2022-07-0306 |
| Title of Abstract | A study on diurnal variability cold pool activity in the Bay of Bengal during summer monsoon using moored buoy observation |
| Authors | Jofia Joseph*, Girishkumar M.S., E. Pattabhi Ram Rao |
| Organisation | Incois |
| Address | Incois, pragathinagar Hyderabad, Telangana, India Pincode: 500090 Mobile: 8129651858 E-mail: jofiajoseph1992@gmail.com |
| Country | India |
| Presentation | Oral |
| Abstract | High temporal resolution (10 min) measurements from RAMA moorings in the central (90°E) Bay of Bengal at 8°N, 12°N and 15°N is used to document the diurnal variability of cold pool activity and its impact on the modulation of near-surface meteorological and oceanographic parameters. In sub-daily time scale a well-defined afternoon (1200-1800 LST) peak in the generation of atmospheric cold pool (42-52% events were occurred during this time period) in the northern Bay of Bengal (15°N and 12°N) is observed. On an average atmospheric cold pool leads to the enhancement of latent and sensible heat loss from the ocean around 100 Wm-2 and 40 Wm-2 respectively. The cold pool intensity (based on air temperature drop) is relatively high in the northern Bay of Bengal. Moreover, the intensity of cold pool is relatively high during morning hours. In response to a cold pool events sensible heat flux is modulated pre-dominantly by sea-air temperature difference (90 %) and latent heat flux is modulated primarily by sea-air specific humidity difference (75 %) and secondarily by wind speed (25 %). Our analysis further, shows that, the reduction in of net shortwave radiation, primarily due to cloud cover and turbulent heat flux associated cold pool that formed in the afternoon hours have potential to modulate sea surface temperature variability. The diurnal evolution of large scale synoptic conditions associated with those cold pool activities is evaluated using six-hour composite of TRMM3b42 rainfall. Our analysis shows that the southeastward propagation of rainfall band is initiated as untidy rainfall maxima in the north-west coast of Bay of Bengal during 0000-0060 LST. The rainfall activity intensified and further moves to offshore and reaches at 15°N and 12°N mooring location during 1200-1800 LST, when maximum coldpool activity observed. |