Origins of Eddy Kinetic Energy in the Bay of Bengal

2018 ◽  
Vol 123 (3) ◽  
pp. 2097-2115 ◽  
Author(s):  
Gengxin Chen ◽  
Yuanlong Li ◽  
Qiang Xie ◽  
Dongxiao Wang
Keyword(s):  
Kinetic Energy ◽  
Bay Of Bengal ◽  
Eddy Kinetic Energy

scholarly journals Barotropic energetics analysis of tropical cyclone Khai Muk

MAUSAM ◽  
2022 ◽  
Vol 64 (1) ◽  
pp. 49-58
Author(s):  
S. BALACHANDRAN
Keyword(s):  
Tropical Cyclone ◽  
Kinetic Energy ◽  
Energy Conversion ◽  
Bay Of Bengal ◽  
Zonal Flow ◽  
Eddy Kinetic Energy ◽  
Initial Growth ◽  
Horizontal Shear ◽  
Absolute Vorticity ◽  
Barotropic Energy Conversion

bl 'kks/k i= esa 11&14 uoEcj 2008 ds nkSjku caxky dh [kkM+h esa cuus vkSj mlds vkxs c<+us okys m".kdfVca/kh; pØokr dSeqd  dh xfrdh; fLFkfr;ksa ds fo’kys"k.k ij fopkj&foe’kZ fd;k x;k tks fupys Lrj ij ifjofrZr ok;qnkc&m".kdfVca/k ¼csjksVªkfid½ mtkZ ij dsfUnzr FkkA bl nkSjku ;g ik;k x;k  fd if’peh iz’kkar egklkxj ls miks".kh; iwohZ gok;sa e/; caxky dh [kkM+h ds mRrj rd c<+h vkSj Åij m)`r vof/k esa Hkwe/;js[kh; if’peh gok;sa ¼iNok¡½ vkbZ-Vh-lh-tsM+- ds nf{k.k rd c<+h ftlds dkj.k {kSfrt; vi:i.k izokg vR;kf/kd ek=k esa cukA blls pØokrh vi:i.k Hkzfeyrk mRiUu gqbZ vkSj fo{kksHk cuk] tks ckn esa m".kdfVca/kh; pØokr dSeqd esa fodflr gks x;kA fupys {kksHkeaM+y esa ewyHkwr {ks=h; izokg ok;qnkcm".kdfVca/k :i ls vfLFkj Fkk ftls fujis{k Hkzfeyrk ds ;kE;ksrjh forj.k ds y{k.k ds ifjorZu }kjk crk;k x;k gS ftlls coaMj ds cuus esa xfrdh; ÅtkZ feyhA bl nkSjku fujis{k Hkzfeyrk ds ek/; {ks=h; izokg vkSj ;kE;ksrjh izo.krk ds chp ldkjkRed lglaca/k Fkk ftlls ok;qnkcm".kdfVca/k }kjk coaMj ek/; izokg dh vUrjfØ;kvksa ds }kjk coaM+j dh xfrdh; ÅtkZ esa o`f) gqbZA ÅtZLoh fo’ys"k.k ls irk pyk gS fd coaM+j okyh xfrdh; ÅtkZ ds ldkjkRed ifjorZu ds mPp nj ds {ks= ifjorhZ ok;qnkc m".kdfVca/k ds ldkjkRed {ks=ksa ls esy [kkrs gSa vkSj ifjorhZ m".kdfVca/k ds ifjek.k Hkzfey mRifRr okys {ks= ds vkl&ikl coaM+j okyh xfrdh; ÅtkZ ds ifjorZu ds LFkkuh; le; ds lkFk esy [kkrs gaSA ewyHkwr {ks=h; izokg ds ;kE;ksrjh vi:i.k }kjk ifjofrZr ok;qnkc m".kdfVca/k ÅtkZ m".kdfVca/kh; pØokr dSeqd ds cuus vkSj mlds vkxs c<+us okys ,d egRoiw.kZ ÅtkZ L=ksr FkkA Analysis of dynamical conditions in respect of formation and growth of tropical cyclone Khai Muk over the Bay of Bengal during 11-14 November 2008 is discussed with focus on barotropic energy conversion at lower level. It is observed that the extension of subtropical easterlies from the Western Pacific in to central Bay of Bengal to the north and equatorial westerlies to the south of ITCZ during the above period constituted a large scale horizontal shear flow. This led to generation of cyclonic shear vorticity and initiation of disturbance which later developed in to tropical cyclone Khai Muk. The basic zonal flow in the lower troposphere was barotropically unstable as depicted by change of sign of meridional distribution of absolute vorticity which provided the kinetic energy for the growth of eddy. There existed positive correlation between mean zonal flow and the meridional gradient of absolute vorticity which favoured increase of eddy kinetic energy through barotropic eddy-mean flow interactions. Energetic analysis indicated that areas of high rate of positive change of eddy kinetic energy coincided with positive areas of barotropic conversion and the magnitude of barotropic conversion matched with local rate of change of eddy kinetic energy around the area of vortex generation. Barotropic energy conversion by meridional shear of basic zonal flow was an important energy source for the formation and initial growth of tropical cyclone Khai Muk.

scholarly journals Simulations of Nearshore Particle-Pair Dispersion in Southern California

2013 ◽  
Vol 43 (9) ◽  
pp. 1862-1879 ◽  
Author(s):  
Leonel Romero ◽  
Yusuke Uchiyama ◽  
J. Carter Ohlmann ◽  
James C. McWilliams ◽  
David A. Siegel
Keyword(s):  
Kinetic Energy ◽  
Southern California ◽  
Separation Distance ◽  
Horizontal Resolution ◽  
Particle Dispersion ◽  
Eddy Kinetic Energy ◽  
Relative Dispersion ◽  
Numerical Resolution ◽  
Relative Diffusivity ◽  
Pair Separation

Abstract Knowledge of horizontal relative dispersion in nearshore oceans is important for many applications including the transport and fate of pollutants and the dynamics of nearshore ecosystems. Two-particle dispersion statistics are calculated from millions of synthetic particle trajectories from high-resolution numerical simulations of the Southern California Bight. The model horizontal resolution of 250 m allows the investigation of the two-particle dispersion, with an initial pair separation of 500 m. The relative dispersion is characterized with respect to the coastal geometry, bathymetry, eddy kinetic energy, and the relative magnitudes of strain and vorticity. Dispersion is dominated by the submesoscale, not by tides. In general, headlands are more energetic and dispersive than bays. Relative diffusivity estimates are smaller and more anisotropic close to shore. Farther from shore, the relative diffusivity increases and becomes less anisotropic, approaching isotropy ~10 km from the coast. The degree of anisotropy of the relative diffusivity is qualitatively consistent with that for eddy kinetic energy. The total relative diffusivity as a function of pair separation distance R is on average proportional to R5/4. Additional Lagrangian experiments at higher horizontal numerical resolution confirmed the robustness of these results. Structures of large vorticity are preferably elongated and aligned with the coastline nearshore, which may limit cross-shelf dispersion. The results provide useful information for the design of subgrid-scale mixing parameterizations as well as quantifying the transport and dispersal of dissolved pollutants and biological propagules.

scholarly journals Numerical simulation and decomposition of kinetic energy in the Central Mediterranean: insight on mesoscale circulation and energy conversion

Ocean Science ◽  
2011 ◽  
Vol 7 (4) ◽  
pp. 503-519 ◽  
Author(s):  
R. Sorgente ◽  
A. Olita ◽  
P. Oddo ◽  
L. Fazioli ◽  
A. Ribotti
Keyword(s):  
Numerical Simulation ◽  
Kinetic Energy ◽  
Energy Conversion ◽  
Ocean Model ◽  
Eddy Kinetic Energy ◽  
Tyrrhenian Sea ◽  
Central Mediterranean ◽  
Baroclinic Energy Conversion ◽  
Sicily Channel ◽  
Mean Kinetic Energy

Abstract. The spatial and temporal variability of eddy and mean kinetic energy of the Central Mediterranean region has been investigated, from January 2008 to December 2010, by mean of a numerical simulation mainly to quantify the mesoscale dynamics and their relationships with physical forcing. In order to understand the energy redistribution processes, the baroclinic energy conversion has been analysed, suggesting hypotheses about the drivers of the mesoscale activity in this area. The ocean model used is based on the Princeton Ocean Model implemented at 1/32° horizontal resolution. Surface momentum and buoyancy fluxes are interactively computed by mean of standard bulk formulae using predicted model Sea Surface Temperature and atmospheric variables provided by the European Centre for Medium Range Weather Forecast operational analyses. At its lateral boundaries the model is one-way nested within the Mediterranean Forecasting System operational products. The model domain has been subdivided in four sub-regions: Sardinia channel and southern Tyrrhenian Sea, Sicily channel, eastern Tunisian shelf and Libyan Sea. Temporal evolution of eddy and mean kinetic energy has been analysed, on each of the four sub-regions, showing different behaviours. On annual scales and within the first 5 m depth, the eddy kinetic energy represents approximately the 60 % of the total kinetic energy over the whole domain, confirming the strong mesoscale nature of the surface current flows in this area. The analyses show that the model well reproduces the path and the temporal behaviour of the main known sub-basin circulation features. New mesoscale structures have been also identified, from numerical results and direct observations, for the first time as the Pantelleria Vortex and the Medina Gyre. The classical kinetic energy decomposition (eddy and mean) allowed to depict and to quantify the permanent and fluctuating parts of the circulation in the region, and to differentiate the four sub-regions as function of relative and absolute strength of the mesoscale activity. Furthermore the Baroclinic Energy Conversion term shows that in the Sardinia Channel the mesoscale activity, due to baroclinic instabilities, is significantly larger than in the other sub-regions, while a negative sign of the energy conversion, meaning a transfer of energy from the Eddy Kinetic Energy to the Eddy Available Potential Energy, has been recorded only for the surface layers of the Sicily Channel during summer.

scholarly journals Numerical simulation and decomposition of kinetic energies in the Central Mediterranean Sea: insight on mesoscale circulation and energy conversion

2011 ◽  
Vol 8 (3) ◽  
pp. 1161-1214 ◽  
Author(s):  
R. Sorgente ◽  
A. Olita ◽  
P. Oddo ◽  
L. Fazioli ◽  
A. Ribotti
Keyword(s):  
Numerical Simulation ◽  
Kinetic Energy ◽  
Energy Conversion ◽  
Mediterranean Sea ◽  
Ocean Model ◽  
Eddy Kinetic Energy ◽  
Central Mediterranean ◽  
Central Mediterranean Sea ◽  
Baroclinic Energy Conversion ◽  
Mean Kinetic Energy

Abstract. The spatial and temporal variability of eddy and mean kinetic energy of the Central Mediterranean Sea has been investigated, from January 2008 to December 2010, by mean of a numerical simulation mainly to quantify the mesoscale dynamics and their relationships with physical forcing. In order to understand the energy redistribution processes, the baroclinic energy conversion has been analysed, suggesting hypotheses about the drivers of the mesoscale activity in this area. The ocean model used is based on the Princeton Ocean Model implemented at 1/32° horizontal resolution. Surface momentum and buoyancy fluxes are interactively computed by mean of standard bulk formulae using predicted model Sea Surface Temperature and atmospheric variables provided by the European Centre for Medium Range Weather Forecast operational analyses. At its lateral boundaries the model is one-way nested within the Mediterranean Forecasting System operational products. The model domain has been subdivided in four sub-regions: Sardinia channel and southern Tyrrhenian Sea, Sicily channel, eastern Tunisian shelf and Libyan Sea. Temporal evolution of eddy and mean kinetic energy has been analysed, on each of the four sub-regions composing the model domain, showing different behaviours. On annual scales and within the first 5 m depth, the eddy kinetic energy represents approximately the 60 % of the total kinetic energy over the whole domain, confirming the strong mesoscale nature of the surface current flows in this area. The analyses show that the model well reproduces the path and the temporal behaviour of the main known sub-basin circulation features. New mesoscale structures have been also identified, from numerical results and direct observations, for the first time as the Pantelleria Vortex and the Medina Gyre. The classical the kinetic energy decomposition (eddy and mean) allowed to depict and to quantify the stable and fluctuating parts of the circulation in the region, and to differentiate the four sub-regions as function of relative and absolute strength of the mesoscale activity. Furthermore the Baroclinic Energy Conversion term shows that in the Sardinia Channel the mesoscale activity, due to baroclinic instabilities, is significantly larger than in the other sub-regions, while a negative sign of the energy conversion, meaning a transfer of energy from the Eddy Kinetic Energy to the Eddy Available Potential Energy, has been recorded only for the surface layers of the Sicily Channel during summer.

scholarly journals On the Role of Asymmetric Convective Bursts to the Problem of Hurricane Intensification: Radiation of Vortex Rossby Waves and Wave–Mean Flow Interactions

2014 ◽  
Vol 71 (6) ◽  
pp. 2057-2077 ◽  
Author(s):  
Konstantinos Menelaou ◽  
M. K. Yau
Keyword(s):  
Kinetic Energy ◽  
Thermal Anomaly ◽  
Eddy Kinetic Energy ◽  
Intensity Change ◽  
Mean Flow ◽  
Symmetric Flow ◽  
Thermal Forcing ◽  
Sensitivity Experiments ◽  
Flow Interactions

Abstract The role of asymmetric convection to the intensity change of a weak vortex is investigated with the aid of a “dry” thermally forced model. Numerical experiments are conducted, starting with a weak vortex forced by a localized thermal anomaly. The concept of wave activity, the Eliassen–Palm flux, and eddy kinetic energy are then applied to identify the nature of the dominant generated waves and to diagnose their kinematics, structure, and impact on the primary vortex. The physical reasons for which disagreements with previous studies exist are also investigated utilizing the governing equation for potential vorticity (PV) perturbations and a number of sensitivity experiments. From the control experiment, it is found that the response of the vortex is dominated by the radiation of a damped sheared vortex Rossby wave (VRW) that acts to accelerate the symmetric flow through the transport of angular momentum. An increase of the kinetic energy of the symmetric flow by the VRW is shown also from the eddy kinetic energy budget. Additional tests performed on the structure and the magnitude of the initial thermal forcing confirm the robustness of the results and emphasize the significance of the wave–mean flow interaction to the intensification process. From the sensitivity experiments, it is found that for a localized thermal anomaly, regardless of the baroclinicity of the vortex and the radial and vertical gradients of the thermal forcing, the resultant PV perturbation follows a damping behavior, thus suggesting that deceleration of the vortex should not be expected.

scholarly journals Interannual Eddy Kinetic Energy Modulations in the Agulhas Return Current

2018 ◽  
Vol 123 (9) ◽  
pp. 6449-6462 ◽  
Author(s):  
Yanan Zhu ◽  
Bo Qiu ◽  
Xiaopei Lin ◽  
Fan Wang
Keyword(s):  
Kinetic Energy ◽  
Eddy Kinetic Energy ◽  
Return Current

Response of the Southern Ocean to the Southern Annular Mode: Interannual Variability and Multidecadal Trend

2010 ◽  
Vol 40 (7) ◽  
pp. 1659-1668 ◽  
Author(s):  
A. M. Treguier ◽  
J. Le Sommer ◽  
J. M. Molines ◽  
B. de Cuevas
Keyword(s):  
Kinetic Energy ◽  
Southern Ocean ◽  
Interannual Variability ◽  
Time Scales ◽  
Meridional Circulation ◽  
Southern Annular Mode ◽  
Eddy Kinetic Energy ◽  
Overturning Circulation ◽  
Annular Mode ◽  
Meridional Overturning

Abstract The authors evaluate the response of the Southern Ocean to the variability and multidecadal trend of the southern annular mode (SAM) from 1972 to 2001 in a global eddy-permitting model of the DRAKKAR project. The transport of the Antarctic Circumpolar Current (ACC) is correlated with the SAM at interannual time scales but exhibits a drift because of the thermodynamic adjustment of the model (the ACC transport decreases because of a low renewal rate of dense waters around Antarctica). The interannual variability of the eddy kinetic energy (EKE) and the ACC transport are uncorrelated, but the EKE decreases like the ACC transport over the three decades, even though meridional eddy fluxes of heat and buoyancy remain stable. The contribution of oceanic eddies to meridional transports is an important issue because a growth of the poleward eddy transport could, in theory, oppose the increase of the mean overturning circulation forced by the SAM. In the authors’ model, the total meridional circulation at 50°S is well correlated with the SAM index (and the Ekman transport) at interannual time scales, and both increase over three decades between 1972 and 2001. However, given the long-term drift, no SAM-linked trend in the eddy contribution to the meridional overturning circulation is detectable. The increase of the meridional overturning is due to the time-mean component and is compensated by an increased buoyancy gain at the surface. The authors emphasize that the meridional circulation does not vary in a simple relationship with the zonal circulation. The model solution points out that the zonal circulation and the eddy kinetic energy are governed by different mechanisms according to the time scale considered (interannual or decadal).

Spatio-Temporal Variability of the Eddy Kinetic Energy in the South Atlantic Ocean

2014 ◽  
Vol 11 (11) ◽  
pp. 2010-2014
Author(s):  
C. M. Cecilio ◽  
D. F. M. Gherardi ◽  
R. B. Souza ◽  
M. Correa-Ramirez
Keyword(s):  
Kinetic Energy ◽  
Atlantic Ocean ◽  
Temporal Variability ◽  
South Atlantic ◽  
Eddy Kinetic Energy ◽  
South Atlantic Ocean ◽  
The South ◽  
Spatio Temporal
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