Search Results

You are looking at 1 - 8 of 8 items for :

  • Air–Sea Interactions from the Diurnal to the Intraseasonal during the PISTON, MISOBOB, and CAMP2Ex Observational Campaigns in the Tropics x
  • All content x
Clear All
Corinne B. Trott, Bulusu Subrahmanyam, Heather L. Roman-Stork, V. S. N. Murty, and C. Gnanaseelan

1. Introduction Intraseasonal oscillations (ISOs) in the Bay of Bengal (BoB) have become a burgeoning topic of interest due to the constantly improving coverage and accuracy of models and observations in the northern Indian Ocean, as well as their impact on monsoon variability. Most of the previous studies have focused on precipitation, sea surface temperature (SST), and atmospheric dynamics, with a few researchers directly focusing on sea surface salinity (e.g., Subrahmanyam et al. 2018 ; Li

Full access
Dipanjan Chaudhuri, Debasis Sengupta, Eric D’Asaro, R. Venkatesan, and M. Ravichandran

warm subsurface ocean temperatures (e.g., Lin et al. 2009 ; Jaimes and Shay 2009 , 2015 ; Yablonsky and Ginis 2013 ; Girishkumar and Ravichandran 2012 ; Lin et al. 2014 ; Balaguru et al. 2018 ). Some recent studies address the interaction between tropical cyclones and the ocean in the presence of a “barrier layer,” that is, a deep, warm isothermal layer lying beneath a shallow, salinity-stratified layer ( Sengupta et al. 2008 ; Balaguru et al. 2012 , 2014 ; Neetu et al. 2012 ; Vincent et

Full access
C. A. Luecke, H. W. Wijesekera, E. Jarosz, D. W. Wang, J. C. Wesson, S.U.P. Jinadasa, H. J. S. Fernando, and W. J. Teague

Abstract

Long-term measurements of turbulent kinetic-energy dissipation rate (ε), and turbulent temperature-variance dissipation rate (χ T) in the thermocline, along with currents, temperature, and salinity were made at two subsurface moorings in the southern Bay of Bengal (BoB). This is a part of a major international program, conducted between July 2018 and June 2019, for investigating the role of the BoB on the monsoon intraseasonal oscillations. One mooring was located on the typical path of the Southwest Monsoon Current (SMC), and the other was in a region where the Sri Lanka Dome is typically found during the summer monsoon. Microstructure and finescale estimates of vertical diffusivity revealed the long-term subthermocline mixing patterns in the southern BoB. Enhanced turbulence and large eddy diffusivities were observed within the SMC during the passage of a subsurface-intensified anticyclonic eddy. During this time, background shear and strain appeared to influence high-frequency motions such as near-inertial waves and internal tides, leading to increased mixing. Near the Sri Lanka Dome, enhanced dissipation occurred at the margins of the cyclonic feature. Turbulent mixing was enhanced with the passage of Rossby waves and eddies. During these events, values of χ T exceeding 10−4 °C2 s−1 were recorded concurrently with ε values exceeding 10−5 W kg −1. Inferred diffusivity peaked well above background values of 10−6 m2 s−1, leading to an annually-averaged diffusivity near 10−4 m2 s−1. Turbulence appeared low throughout much of the deployment period. Most of the mixing occurred in spurts during isolated events.

Restricted access
Jai Sukhatme, Dipanjan Chaudhuri, Jennifer MacKinnon, S. Shivaprasad, and Debasis Sengupta

16 m marked by purple colored track segment in (a) and by the vertical black lines in (b) and (c). Though the entire leg of the cruise is shown, calculations of spectra are restricted to the portion where the ship followed a straight line. Density stratification is estimated using uCTD data where available (SN88 and SN100), and in the other cases, from monthly temperature and salinity data from the Roemmich–Gilson 1° gridded Argo dataset ( Roemmich and Gilson 2009 ). Specifically, we take a 2

Restricted access
Kenneth G. Hughes, James N. Moum, and Emily L. Shroyer

waves (e.g., Lueck 2016 ). Recent examples of surface-following platforms include a sailboard adapted to measure salinity profiles in the top meter of the ocean ( Asher et al. 2014 ), a trimaran adapted to measure atmospheric turbulence just above the sea surface ( Bourras et al. 2014 ), and “SWIFT” drifters to measure near-surface turbulence and shear ( Thomson 2012 ; Thomson et al. 2019 ). Like Asher et al. (2014) , our platform is towed so as to sample undisturbed water outside the ship’s wake

Restricted access
D. A. Cherian, E. L. Shroyer, H. W. Wijesekera, and J. N. Moum

1. Introduction The Bay of Bengal (the Bay) is the eastern semi-enclosed basin of the north Indian Ocean. The shallow salinity-controlled stratification in the upper Bay allows for rapid coupling with the atmosphere, and modulation of sea surface temperature (SST) within the Bay of Bengal has been linked to variations in the South Asian monsoon (e.g., Vecchi and Harrison 2002 ; Roxy 2014 ). The influence of processes controlling upper-ocean stratification thus extends beyond the physical

Free access
Kenneth G. Hughes, James N. Moum, and Emily L. Shroyer

profiles of temperature T ( z ), and sometimes salinity and velocity u ( z ). Several idealizations have been proposed for use in either climate models or operational procedures like SST corrections. These include linear T and u ( Fairall et al. 1996 ), T and u ∝ z −1/3 ( Fine et al. 2015 ; Large and Caron 2015 ), and T ∝ e − z with either a wind speed–dependent depth scale ( Gentemann et al. 2009 ) or a depth-dependent phase lag ( Matthews et al. 2014 ). These latter two studies

Free access
Sebastian Essink, Verena Hormann, Luca R. Centurioni, and Amala Mahadevan

-surface circulation of the global ocean and to provide SST and sea level pressure data. These data are important for calibration and validation of satellite-derived SST datasets (e.g., Zhang et al. 2009 ) and for numerical weather prediction ( Centurioni et al. 2017 ; Horányi et al. 2017 ). Drifters were released at the edge of a mesoscale cyclonic eddy and across a strong salinity and density front ( Figs. 1a,b ). With the goal of resolving motions over a wide range of length scales, we deployed drifters such

Full access