Diurnal variability of atmospheric cold pool events and associated air-sea interactions in the Bay of Bengal during the summer monsoon

Joseph, Jofia; Girishkumar, M. S.; McPhaden, Michael J.; Rao, E. Pattabhi Rama

doi:10.1007/s00382-020-05506-w

Cited by 6 publications

(10 citation statements)

References 48 publications

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“…9 a and S3 ). The enhancement of near-surface specific humidity due to increasing sea surface temperature (SST) (specific humidity at the sea surface is defined as its saturation value with respect to SST) and reduction in air specific humidity due to entrainment of dry planetary boundary layer into the surface layer owing to the growth of atmospheric ML might be the plausible explanation for the increased evaporation during the daytime 27 , 28 (Figs. 3 f and S3 ).…”

Section: Resultsmentioning

confidence: 99%

Observational evidence of salt finger in the diurnal thermocline

Ashin

Girishkumar

D’Asaro

et al. 2023

Sci Rep

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Due to strong turbulent mixing, the ocean surface boundary layer region is generally not conducive to double diffusion. However, vertical microstructure profiles observations in the northeastern Arabian Sea during May 2019 imply the formation of salt fingers in the diurnal thermocline (DT) region during the daytime. In the DT layer, conditions are favorable for salt fingering: Turner angle values are between 50 and 55° with both temperature and salinity decreasing with depth; shear-driven mixing is weak with a turbulent Reynolds number of about 30. The presence of salt fingering in the DT is confirmed by the presence of staircase-like structures with step sizes larger than the Ozmidov length and by the dissipation ratio that is larger than the mixing coefficient. The unusual daytime salinity maximum in the mixed layer that supports salt fingering is primarily due to a daytime reduction in vertical entrainment of fresh water along with minor contributions from evaporation and horizontal advection and a significant contribution from detrainment processes.

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Section: Resultsmentioning

confidence: 99%

Observational evidence of salt finger in the diurnal thermocline

Ashin

Girishkumar

D’Asaro

et al. 2023

Sci Rep

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“…Downwelling longwave radiation data from the mooring were in error during the study period, so that downwelling longwave radiation data from Clouds and the Earth's Radiant Energy System (CERES) with 1° × 1° spatial resolution and one‐hour temporal resolution (Wielicki et al., 1996) were used instead to estimate LHF from the bulk algorithm. A comparison of downwelling longwave radiation data from CERES with measurements from RAMA buoys at 15°N, 90°E in the central BoB and 5°N, 95°E in the eastern equatorial Indian Ocean demonstrated that CERES data were a reasonable replacement for missing in‐situ data at BD11 (A. R. Aparna & Girishkumar, 2022; Girishkumar et al., 2021; Joseph et al., 2021). BD11 also measures sub‐surface temperature and salinity though these data are not used in the present study.…”

Section: Methodsmentioning

confidence: 99%

“…There have been many previous attempts to document air-sea interaction processes in the BoB that are important of weather and climate (Bhat & Fernando, 2016;Bhat et al, 2001;Cyriac et al, 2016;Dey et al, 2017;Girishkumar et al, 2011Girishkumar et al, , 2017Joseph et al, 2021;Prasad, 2004;Praveen Kumar et al, 2017;Rao and Sivakumar, 2000;Sengupta and Ravichandran, 2001;Shenoi et al, 2002;Srivastava et al, 2018;Thangaprakash et al, 2016;Webster et al, 2002;Weller et al, 2016Weller et al, , 2019Yu et al, 2007). These studies helped to advance our knowledge of variability across a broad range of phenomena spanning intraseasonal to decadal time scales.…”

Section: Plain Language Summarymentioning

confidence: 99%

“…The possibility now exists to explore processes at work on very short time scales in novel and unique ways. For example, based on the measurements from three RAMA moorings in the central BoB, Joseph et al (2021) and Girishkumar et al (2021) examined sub-daily variability of atmospheric cold pool events and their effects on surface heat fluxes and SST. In addition, Turk et al (2021) and Giglio et al (2022) used moored buoy observations to document sub-daily wind speed variability in open ocean regions of the tropics.…”

Section: Plain Language Summarymentioning

confidence: 99%

“…For example, based on the measurements from three RAMA moorings in the central BoB, Joseph et al. (2021) and Girishkumar et al. (2021) examined sub‐daily variability of atmospheric cold pool events and their effects on surface heat fluxes and SST.…”

Section: Introductionmentioning

confidence: 99%

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Seasonal Variation of the Land Breeze System in the Southwestern Bay of Bengal and Its Influence on Air‐Sea Interactions

et al. 2023

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Sea surface temperature (SST) in the Bay of Bengal (BoB) plays a vital role in determining the spatio-temporal variability of Indian summer monsoon precipitation (Jiang & Li, 2011;Samanta et al., 2018;Shenoi et al., 2002). Due to the persistent occurrence of the relatively thin salt-stratified mixed layers, primarily owing to a large influx of freshwater from intense precipitation and continental rivers (Girishkumar et al., 2011;Rao and Sivakumar, 2003;Shetye et al., 1996;Thadathil et al., 2007), SST in the BoB is highly sensitive to surface fluxes (Duncan & Han, 2009). Moreover, the SST in the BoB is always higher than 28°C (Shenoi et al., 2002), a favorable condition for the formation of deep convection in the tropics. Due to the high mean SST, a small change in its magnitude can significantly feedback to the overlying atmosphere so as to influence the amplitude of intraseasonal and interannual signals over the BoB. Hence, it is imperative to understand the processes affecting air-sea fluxes that modulate SST in the BoB on different temporal scales to better represent ocean-atmosphere interactions in weather and climate forecast models.

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