Eddies in the Red Sea: A statistical and dynamical study

Sea level anomaly (SLA) data spanning 1992–2012 were analyzed to study the statistical properties of eddies in the Red Sea. An algorithm that identifies winding angles was employed to detect 4998 eddies propagating along 938 unique eddy tracks. Statistics suggest that eddies are generated across the entire Red Sea but that they are prevalent in certain regions. A high number of eddies is found in the central basin between 18°N and 24°N. More than 87% of the detected eddies have a radius ranging from 50 to 135 km. Both the intensity and relative vorticity scale of these eddies decrease as the eddy radii increase. The averaged eddy lifespan is approximately 6 weeks. AEs and cyclonic eddies (CEs) have different deformation features, and those with stronger intensities are less deformed and more circular. Analysis of long-lived eddies suggests that they are likely to appear in the central basin with AEs tending to move northward. In addition, their eddy kinetic energy (EKE) increases gradually throughout their lifespans. The annual cycles of CEs and AEs differ, although both exhibit significant seasonal cycles of intensity with the winter and summer peaks appearing in February and August, respectively. The seasonal cycle of EKE is negatively correlated with stratification but positively correlated with vertical shear of horizontal velocity and eddy growth rate, suggesting that the generation of baroclinic instability is responsible for the activities of eddies in the Red Sea.

[1]  P. L. Traon,et al.  AN IMPROVED MAPPING METHOD OF MULTISATELLITE ALTIMETER DATA , 1998 .

[2]  J. Font,et al.  Identification of Marine Eddies from Altimetric Maps , 2003 .

[3]  Wei Zhuang,et al.  Intraseasonal variability in sea surface height over the South China Sea , 2010 .

[4]  Frits H. Post,et al.  Detection, quantification, and tracking of vortices using streamline geometry , 2000, Comput. Graph..

[5]  Y. Chao,et al.  Caribbean Sea eddies inferred from TOPEX/POSEIDON altimetry and a 1/6° Atlantic Ocean model simulation , 1999 .

[6]  Rosemary Morrow,et al.  YEARS OF SATELLITE ALTIMETRY AND MESOSCALE OCEAN DYNAMICS , 2009 .

[7]  D. Stammer.  On Eddy Characteristics, Eddy Transports, and Mean Flow Properties , 1998 .

[8]  G. Larnicol,et al.  Mediterranean sea eddy kinetic energy variability from 11 years of altimetric data , 2005 .

[9]  K. S. Smith.  The geography of linear baroclinic instability in Earth's oceans , 2007 .

[10]  B. Qiu,et al.  Seasonal Eddy Field Modulation of the North Pacific Subtropical Countercurrent : TOPEX / Poseidon Observations and Theory , 1999 .

[11]  Gurvan Madec,et al.  Large-scale impacts of submesoscale dynamics on phytoplankton: Local and remote effects , 2012 .

[12]  Fabrice Hernandez,et al.  Mapping mesoscale variability of the Azores Current using TOPEX/POSEIDON and ERS 1 altimetry, together with hydrographic and Lagrangian measurements , 1995 .

[13]  Ibrahim Hoteit,et al.  Seasonal overturning circulation in the Red Sea: 2. Winter circulation , 2014 .

[14]  Lakshmi Kantha,et al.  An oceanographic nowcast/forecast system for the Red Sea , 1997 .

[15]  Gurvan Madec,et al.  Modifications of gyre circulation by sub-mesoscale physics , 2010 .

[16]  E. T. Eady,et al.  Long Waves and Cyclone Waves , 1949 .

[17]  D. Chelton,et al.  Global observations of large oceanic eddies , 2007 .

[18]  B. Qiu.  Seasonal Eddy Field Modulation of the North Pacific Subtropical Countercurrent: TOPEX/Poseidon Observations and Theory , 1999 .

[19]  R. Greatbatch,et al.  On the seasonal variability of eddy kinetic energy in the Gulf Stream region , 2008 .

[20]  G. Dibarboure,et al.  Mesoscale Mapping Capabilities of Multiple-Satellite Altimeter Missions , 1999 .

[21]  R. Harcourt,et al.  Three-Dimensional Structure and Temporal Evolution of Submesoscale Thermohaline Intrusions in the North Pacific Subtropical Frontal Zone , 2010 .

[22]  Yu-Lin Chang,et al.  Instability of the North Pacific subtropical countercurrent , 2014 .

[23]  Ibrahim Hoteit,et al.  State estimates and forecasts of the loop current in the Gulf of Mexico using the MITgcm and its adjoint , 2013 .

[24]  M. Lozier.  Evidence for Large-Scale Eddy-Driven Gyres in the North Atlantic , 1997 .

[25]  Lee-Lueng Fu,et al.  Eddy dynamics from satellite altimetry , 2010 .

[26]  Ibrahim Hoteit,et al.  Remote Sensing the Phytoplankton Seasonal Succession of the Red Sea , 2013, PloS one.

[27]  D. Stammer.  Global Characteristics of Ocean Variability Estimated from Regional TOPEX/POSEIDON Altimeter Measurements , 1997 .

[28]  D. Olson,et al.  Stability of the Sargasso Sea Subtropical Frontal Zone , 1994 .

[29]  D. Chelton,et al.  Global observations of nonlinear mesoscale eddies , 2011 .

[30]  Gengxin Chen,et al.  Mesoscale eddies in the South China Sea: Mean properties, spatiotemporal variability, and impact on thermohaline structure , 2011 .

[31]  Alexis Chaigneau,et al.  Mesoscale eddies off Peru in altimeter records: Identification algorithms and eddy spatio-temporal patterns , 2008 .

[32]  Gilles Reverdin,et al.  Global high-resolution mapping of ocean circulation from TOPEX/Poseidon and ERS-1 and -2 , 2000 .

[33]  E. Stanev,et al.  Eddy Processes in Semienclosed Seas: A Case Study for the Black Sea , 1997 .

[34]  Ibrahim Hoteit,et al.  Exploring the Red Sea seasonal ecosystem functioning using a three‐dimensional biophysical model , 2014 .

[35]  C. Garrett,et al.  The shallow thermohaline circulation of the Red Sea , 1997 .

[36]  Ibrahim Hoteit,et al.  Seasonal overturning circulation in the Red Sea: 1. Model validation and summer circulation , 2014 .

[37]  C. Eden,et al.  Sources of Eddy Kinetic Energy in the Labrador Sea , 2002 .

[38]  B. Sanderson.  Structure of an eddy measured with drifters , 1995 .

[39]  Boris Dewitte,et al.  Eddy activity in the four major upwelling systems from satellite altimetry (1992-2007) , 2009 .

[40]  Detlef Stammer,et al.  Steric and wind-induced changes in TOPEX/POSEIDON large-scale sea surface topography observations , 1997 .

[41]  Hui Wang,et al.  Seasonal variation of eddy kinetic energy in the South China Sea , 2012, Acta Oceanologica Sinica.

[42]  Detlef Quadfasel,et al.  Gyre-scale circulation cells in the Red Sea , 1993 .

[43]  J. Farrar,et al.  Zonal surface wind jets across the Red Sea due to mountain gap forcing along both sides of the Red Sea , 2009 .

[44]  Carl Wunsch,et al.  Temporal changes in eddy energy of the oceans , 1999 .

[45]  Yue Fang,et al.  A review on the South China Sea western boundary current , 2012, Acta Oceanologica Sinica.

[46]  Jilan Su,et al.  The numerical study of the South China Sea upper circulation characteristics and its dynamic mechanism, in winter , 2002 .

[47]  J. Pedlosky,et al.  Vortex generation by topography in locally unstable baroclinic flows , 2003 .

[48]  F. Schott,et al.  Seasonal to interannual variability of the eddy field in the Labrador Sea from satellite altimetry , 2004 .

[49]  The CLS 01 Mean Sea Surface : A validation with the GSFC 00 . 1 surface , 2002 .

[50]  Cheinway Hwang,et al.  TOPEX//Poseidon observations of mesoscale eddies over the Subtropical Countercurrent: Kinematic characteristics of an anticyclonic eddy and a cyclonic eddy , 2004 .

[51]  S. K. Robinson,et al.  Coherent Motions in the Turbulent Boundary Layer , 1991 .

[52]  V. Kourafalou,et al.  Simulating the dynamics and intensification of cyclonic Loop Current Frontal Eddies in the Gulf of Mexico , 2012 .

[53]  William E. Johns,et al.  Observations of the summer Red Sea circulation , 2007 .

[54]  Yongqiang Yu,et al.  Eddy energy sources and sinks in the South China Sea , 2013 .

[55]  Aike Beckmann,et al.  Effects of increased horizontal resolution in a simulation of the North Atlantic Ocean , 1994 .

[56]  Amy S. Bower,et al.  The response of the Red Sea to a strong wind jet near the Tokar Gap in summer , 2013 .

[57]  James C. McWilliams,et al.  Eddy properties in the California Current System , 2011 .

[58]  Jorge Tam,et al.  Average circulation, seasonal cycle, and mesoscale dynamics of the Peru Current System: A modeling approach , 2005 .