Pathways of eddies in the South Atlantic Ocean revealed from satellite altimeter observations
|
|
- Ross Hugh Higgins
- 5 years ago
- Views:
Transcription
1 GEOPHYSICAL RESEARCH LETTERS, VOL. 33,, doi: /2006gl026245, 2006 Pathways of eddies in the South Atlantic Ocean revealed from satellite altimeter observations Lee-Lueng Fu 1 Received 8 March 2006; revised 6 June 2006; accepted 9 June 2006; published 22 July [1] The majority of the kinetic energy of ocean currents is contained in the mesoscale eddies. The pathways of ocean eddies, which are the weather of ocean circulation, are mapped from space using a decade-long record of sea surface height measured by two simultaneously flying satellite radar altimeters. The speed and direction of the propagation of eddies in the South Atlantic Ocean are presented in the paper. The patterns of the eddy propagation velocity reveal the effects of the interaction between mean flow and eddies with strong influence of bottom topography. The information describes a unique property of the ocean general circulation and serves as a basis for testing ocean models. Citation: Fu, L.-L. (2006), Pathways of eddies in the South Atlantic Ocean revealed from satellite altimeter observations, Geophys. Res. Lett., 33,, doi: /2006gl Introduction [2] The variability of ocean currents is dominated by the mesoscale eddies, characterized by a time scale on the order of 100 days and a spatial scale on the order of 100 km [Robinson, 1983]. The generic term eddies is used here to represent the various forms of ocean current variability at the mesoscale: vortices, fronts, planetary waves, and current meanders. Eddies are the oceanic analog of weather in the atmosphere. They contain most of the kinetic energy of the circulation of the ocean and play important roles in determining the water properties of the ocean: temperature, salinity, dissolved gases, and nutrients. The distribution of eddy energy in the ocean has been well mapped from space using satellite altimeter observations [Cheney et al., 1983; Zlotnicki et al., 1989; Stammer, 1997; Ducet et al., 2000]. However, the patterns of the movement of eddies and their propagation velocity, or the pathways of ocean eddies, are more difficult to study due to the lack of long and global observations with sufficient spatial and temporal resolutions. Jacobs et al. [2001] provided a smoothed estimate of the eddy propagation velocity of the global ocean using a method of binned covariance. The same method was applied to the North Atlantic Ocean by Brachet et al. [2004]. In the present study, the combined data from the TOPEX/Poseidon (T/P hereafter) and ERS altimeters are used to construct a high-resolution map of the pathways of ocean eddies in the South Atlantic Ocean, showing the details of the interaction between mean flow and eddies with strong influence of bottom topography. The information describes a unique property of the ocean general circulation and serves as a basis for testing ocean models as well as for constraints in data assimilation and empirical prediction of eddy movement. The approach can be readily applied to the global oceans. 2. Data and Methods [3] The combined data from the T/P and ERS altimeters are the first decade-long record that is useful for tracking the movement of ocean eddies in two dimensions. Although the spatial resolution of a radar altimeter is typically 6 7 km along the satellite s ground tracks, the wide separation between the ground tracks, typically km for a single altimeter, limits the resolution of eddy variability in the satellite s cross-track direction. When the data from the two satellites are combined with the use of an objective mapping technique, the resulting spatial resolution is approximately 150 km in wavelength [Ducet et al., 2000], covering a substantial portion of the mesoscale spectrum (also see Chelton and Schlax [2003] for the estimate of a lower spatial resolution). This data set, available form the French AVISO data center ( com/html/mod_actu/public/welcome_uk.php3, 2006), allows the tracking of large ocean eddies for studying their propagation velocity and pathways. [4] The propagation velocity of eddies is computed using a space-time lagged correlation analysis similar to the maximum cross correlation method [Emery et al., 1986]. At a given location, the sea surface height (SSH) anomalies were computed as the residuals after a time mean was removed from the SSH time series. The correlations of the SSH anomalies with all the neighboring SSH anomalies at various time lags were computed. Such space-time lagged correlation analysis was performed to estimate the speed and direction of the maximum correlations as they move in space and time. [5] The AVISO altimetry data are available on 1/3 degree Mercator grids, with the meridional grid spacing kept the same as the zonal grid spacing of 1/3 degree longitude, varying from 37 km at the equator to 24 km at 50 latitude. At each grid node location (x, y), the cross-correlations (C x,y ) of the SSH time series (h) with others in a square box were computed for time lags DT in multiples of 7 days (the time step of the data) as C x;y ðdx; Dy; DT Þ ¼ hx; ð y; t Þhxþ ð Dx; y þ Dy; t þ DTÞ 1 Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA. Copyright 2006 by the American Geophysical Union /06/2006GL where Dx and Dy are the spatial lags and the over bar denotes time averaging. At each time lag, the location of the maximum correlation was identified and a velocity was estimated from the time lag and the distance of the location 1of5
2 FU: EDDIES IN THE SOUTH ATLANTIC OCEAN Figure 1. The color shading displays the standard deviation of sea surface height in cm. The arrows show the vectors of eddy propagation velocity. A sample vector of 10 km/day is shown at the lower right corner. The two colors of the arrows are for easy viewing. South latitudes and west longitudes are shown in negative numbers and east longitudes in positive numbers. from the origin. An average velocity vector (u, v) weighted by the correlation coefficients was then computed from the estimates at various time lags as X ðu; vþ ¼ i ðdxi =DTi ; Dyi =DTi ÞCi X C i i correlation analysis. Since the space and time lags of the correlation analysis are chosen for the mesoscales, the estimated velocities represent the speed and direction of the propagation of ocean eddy variability. 3. Results where Ci is the maximum correlation at DTi, and Dxi, Dyi represent the location of the maximum correlation. The average velocity was then assigned to the eddy propagation velocity at the given grid node. The size of the box for computing the correlations was determined by the estimated speed and the time lag. To focus on the mesoscale, the time lags were limited to less than 70 days and the dimension of the box was generally less than 400 km. The resulting velocities are associated with the variabilities that dominate the variance of the SSH time series at the scales of the [6] Displayed in color shades in Figure 1 is the standard deviation of SSH measured by the satellite altimeters, showing the intensity of eddy variability. Superimposed on the eddy variability are the velocity vectors estimated from tracking the movement of eddies in the time series of SSH using the method described in Section 2. The velocity vectors represent the speed and direction of the horizontal propagation of ocean eddy variability. Most previous studies of the movement of ocean eddies were based on visual tracking of identifiable features in time sequence of SSH maps. For example, studies of the migration of eddies shed 2 of 5
3 FU: EDDIES IN THE SOUTH ATLANTIC OCEAN Figure 2. A close-up of the eddy propagation velocity in the Argentine Basin. The color shading displays the depths of the ocean bottom. into the South Atlantic from the Agulhas Current and its retroflection off the southern tip of South Africa [Gordon and Haxby, 1990; Byrne et al., 1995] show that these eddies were often traceable for almost two years on their journey toward the east coast of South America. Morrow et al. [2004] applied an objective method to tracking the movement of individual eddies over large distance. Instead of a Lagrangian description of the movement of individual eddies as reported in the previous studies, the space-time correlation analysis used in the present study provides an Eulerian description of the eddy propagation velocity. As shown in Figure 1, the technique has mapped the northwestward propagation velocities of the eddies originated from the Agulhas Current region, showing a typical speed of 3 4 km/day. After leaving the energetic source region, the eddies essentially propagate westward in a vast region of westward propagation velocity north of 35 S. The region is located at the northern part of the subtropical gyre with northwestward mean flow, which may have contributed to the westward motion of the eddies to be discussed later. [7] Along the west coast of Africa, one can see the influence of the northward flowing Benguela Current on the northward component of eddy propagation velocity. Although the eddy signals are quite weak here, their horizontal propagation is highly organized, especially in the region of strong upwelling near S. This is also the region where the cold Benguela current meets the warm coastal waters from the north, a region of frequent eddy shedding into the open ocean [Cole and Villacastin, 2000]. Near 20 S along the east coast of South America is a region of divergence of eddy propagation velocity. Eddies move northward in the region north of 20 S and southward in the region south of 20 S. This is in the vicinity where the Atlantic South Equatorial Current diverges into northward and southward flows. [8] The influence of the Brazil Current is clearly seen between 20 S and 35 S, creating an organized band of southwestward eddy propagation velocity. South of 40 S and west of 40 W, clear indications are shown of the effects of the Antarctic Circumpolar Current (ACC) and the Malvinas Current. The eddy propagation velocities are highly correlated with the paths of the two currents. In the region of maximum eddy variability associated with the confluence of the Brazil Current and the Malvinas Current, the eddy propagation velocities are surprisingly low. On the other hand, a highly organized pattern of anticlockwise eddy propagation velocity is situated in an area of relatively low eddy variability centered at 45 S and 45 W, surrounded by high eddy variability. This region of low eddy variability is filled with barotropic circulation (uniform current velocity from the ocean s top to bottom) called the Zapiola Anticyclone [Saunders and King, 1995; de Miranda et al., 1999]. Apparently, the anticlockwise mean flow has a significant effect on the propagation of eddies in the region. To the east of the Zapiola Anticyclone, the patterns of the eddy propagation velocity reveal the swiftest part of the ACC in the region. The two meandering streams of generally eastward velocity vectors between 10 W and10 E reflect the paths of the Subantarctic and Polar Fronts of the ACC [Orsi et al., 1995]. [9] The complex patterns of eddy propagation velocity in the southwestern part of the South Atlantic, called the Argentine Basin, are superimposed on a map of the ocean s bathymetry in Figure 2. The steering effects of the bathymetry are clearly illustrated. To a large extent, the eddy propagation velocity is in alignment with the direction of the mean flow which is affected by the bathymetry. The generation of eddies is also affected by the bathymetry. The eddies are carried by the mean currents over the depths of the eddies vertical extent. The eddies also have their own intrinsic propagation velocity in the absence of any mean flow [Flierl, 1977; McWilliams and Flierl, 1979]. The net propagation velocity is caused by a combination of the intrinsic eddy propagation and the advection of mean flow. In general, the eddy propagation velocity is several fold less than the surface velocity of the mean flow. However, the patterns of the eddy propagation velocity reveal many details of the mean flow in the region: the meander of the ACC just east of the Drake Passage, the northward velocities in the path of the Malvinas Current over the continental slope, the anticyclonic velocities around the submarine bank at 50 S and 42 W as well as the South Georgia Island (55 S, 37 W). [10] The most striking pattern of the eddy propagation velocity is associated with the anti-clockwise Zapiola Anticyclone surrounding the Zapiola Rise in the middle of an abyssal plane. The details of the velocity vectors even reveal the shape of the Zapiola Rise, especially the wavy patterns along 47 S between 45 W and 38 W. As noted earlier, the mean flow of the region extends from surface to bottom as a tight anticyclonic recirculation gyre. This gyre is believed to be driven by the strong eddy field of the Argentine Basin [de Miranda et al., 1999]. It is interesting to note that the eddies themselves propagate along the path of the mean current, at a speed comparable to that of the mean current. [11] There is firm evidence in Figures 1 and 2 for the effects of mean flow on the eddy propagation velocity. To further illustrate the effects, displayed in Figure 3 is the speed of eddy propagation superimposed by the contours of the dynamic topography of the ocean [Niiler et al., 2003]. 3of5
4 FU: EDDIES IN THE SOUTH ATLANTIC OCEAN the ACC and the Malvinas Current also have strong deep currents to carry eddies in the direction of the mean flow with significant speeds. Figure 3. The color shading displays the speed of eddy propagation in km/day. The contours represent the surface dynamic topography. The contour intervals are 10 cm. The highest values are in the center of the subtropical gyre enclosed by the 20 cm contour. The dashed line is a schematic representation of the ridge of the subtropical gyre with northwestward mean flow in the north and eastward mean flow in the south as indicated by the arrows. There is a sharp demarcation between the high speeds of 4 6 km/day north of 30 S and the low speeds of 0 2 km/day south of 30 S. This transition occurs along a ridge of the dynamic topography, which divides the subtropical gyre of the South Atlantic into two regions. The general direction of the surface flow is eastward in the south and northwestward in the north. Since the intrinsic propagation velocity of an eddy has a westward component [Flierl, 1977; McWilliams and Flierl, 1979], this component is reinforced by the mean flow in the north and compensated by the mean flow in the south. When the mean flow has strong eastward velocity as in the ACC, it is able to reverse eddy propagation from its intrinsic westward direction into eastward direction with substantial speeds as shown in the region of 50 W 70 W, 50 S 60 S as well as 20 W 10 E, 45 S 55 S (also see Figure 1). [12] The high speed in the region west of 35 W and south of 35 S is interesting. The surface flow in the region is generally toward the east as indicated by the dynamic topography and should therefore reduce the eddy propagation speed. However, the dynamic topography at 3000 m depth indicates that the anticyclonic deep circulation in the Zapiola region has a branch extending northward to 35 S [Niiler et al., 2003]. Therefore the deep currents in the region are to the west in opposition to the surface currents. The eddy propagation velocities are apparently affected by the deep currents instead of the surface currents. The largest eddy propagation velocities occur in the region where the westward barotropic currents are known to be the strongest just north of the Zapiola Rise along 45 S. South of the Zapiola Rise, the eastward deep currents are strong enough to carry the eddies eastward with substantial speeds. Both 4. Conclusions [13] The new information on the propagation velocity of ocean eddies obtained from the study represents a unique asset of long-term measurement of global sea surface height from multiple satellites. The decade-long record length provides a large degree of freedom in the velocity estimates, leading to a reliable description of this property of the ocean general circulation. It is a property reflecting the interplay between ocean eddies and mean flow, a subject of great importance in our pursuit of understanding and modeling ocean circulation and its effects on climate and ecosystem. The information on eddy propagation velocity thus provides a basis for testing the performance of ocean general circulation models. [14] Acknowledgments. The author would like to acknowledge stimulating discussions with Dudley Chelton of Oregon State University. This work was in part inspired by his interesting animation of eddy motions from altimetry observations. The research presented in the paper was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautic and Space Administration. Support from the TOPEX/Poseidon and Jason Projects is acknowledged. References Brachet, S., P. Y. Le Traon, and C. Le Provost (2004), Mesoscale variability from a high-resolution model and from altimeter data in the North Atlantic Ocean, J. Geophys. Res., 109, C12025, doi: /2004jc Byrne, D. A., A. L. Gordon, and W. F. Haxby (1995), Agulhas eddies: A synoptic view using Geosat ERM data, J. Phys. Oceanogr., 25, Chelton, D. B., and M. G. Schlax (2003), The accuracies of smoothed sea surface height fields constructed from tandem satellite altimeter datasets, J. Atmos. Oceanic Technol., 20, Cheney, R. E., J. G. March, and B. D. Beckley (1983), Global mesoscale variability from collinear tracks of Seasat Altimeter data, J. Geophys. Res., 88, Cole, J., and C. Villacastin (2000), Sea surface temperature variability in the northern Benguela upwelling system, and implications for fisheries research, Int. J. Remote Sens., 21, de Miranda, A. P., B. Barnier, and W. K. Dewar (1999), On the dynamics of the Zapiola Anticyclone, J. Geophys. Res., 104, 21,137 21,150. Ducet, N., P. Y. Le Traon, and G. Reverdin (2000), Global high resolution mapping of ocean circulation from the combination of TOPEX/ POSEIDON and ERS-1/2, J. Geophys. Res., 105, 19,477 19,498. Emery, W. J., A. C. Thomas, M. J. Collins, W. R. Crawford, and D. L. Mackas (1986), An objective procedure to compute advection from sequential infrared satellite images, J. Geophys. Res., 91, 12,865 12,879. Flierl, G. R. (1977), The application of linear quasigeostrophic dynamics to Gulf Stream Rings, J. Phys. Oceanogr., 7, Gordon, A. L., and W. F. Haxby (1990), Agulhas eddies invade the South Atlantic: Evidence from Geosat altimeter and shipboard conductivitytemperature-depth survey, J. Geophys. Res., 95, Jacobs, G. A., C. N. Barron, and R. C. Rhodes (2001), Mesoscale characteristics, J. Geophys. Res., 106, 19,581 19,595. McWilliams, J. C., and G. R. Flierl (1979), On the evolution of isolated non-linear vortices, J. Phys. Oceanogr., 9, Morrow, R., B. Florence, D. Griffin, and J. Sudre (2004), Divergent pathways of cyclonic and anti-cyclonic ocean eddies, Geophys. Res. Lett., 31, L24311, doi: /2004gl Niiler, P. P., N. A. Maximenko, and J. C. McWilliams (2003), Dynamically balanced absolute sea level of the global ocean derived from near-surface velocity observations, Geophys. Res. Lett., 30(22), 2164, doi: / 2003GL Orsi, A. H., T. Whitworth III, and W. D. Nowlin Jr. (1995), On the meridional extent and fronts of the Antarctic Circumpolar Current, Deep Sea Res., 42, Robinson, A. R., (Ed.) (1983), Eddies in Marine Science, 609 pp., Springer, New York. 4of5
5 FU: EDDIES IN THE SOUTH ATLANTIC OCEAN Saunders, P. M., and B. A. King (1995), Bottom currents derived from a shipborne ADCP on the WOCE Cruise A11 in the South Atlantic, J. Phys. Oceanogr., 25, Stammer, D. (1997), Global characteristics of ocean variability estimated from regional TOPEX/POSEIDON altimeter measurements, J. Phys. Oceanogr., 27, Zlotnicki, V., L.-L. Fu, and W. Patzert (1989), Seasonal variability in global sea level observed with GEOSAT altimetry, J. Geophys. Res., 94, 17,959 17,969. L.-L. Fu, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA. (llf@pacific.jpl.nasa.gov) 5of5
Global observations of large oceanic eddies
GEOPHYSICAL RESEARCH LETTERS, VOL. 34, L15606, doi:10.1029/2007gl030812, 2007 Global observations of large oceanic eddies Dudley B. Chelton, 1 Michael G. Schlax, 1 Roger M. Samelson, 1 and Roland A. de
More informationGlobal Variability of the Wavenumber Spectrum of Oceanic Mesoscale Turbulence
802 J O U R N A L O F P H Y S I C A L O C E A N O G R A P H Y VOLUME 41 Global Variability of the Wavenumber Spectrum of Oceanic Mesoscale Turbulence YONGSHENG XU AND LEE-LUENG FU Jet Propulsion Laboratory,
More informationAtmospheric driving forces for the Agulhas Current in the subtropics
Click Here for Full Article GEOPHYSICAL RESEARCH LETTERS, VOL. 34, L15605, doi:10.1029/2007gl030200, 2007 Atmospheric driving forces for the Agulhas Current in the subtropics A. Fetter, 1 J. R. E. Lutjeharms,
More informationEddy-resolving Simulation of the World Ocean Circulation by using MOM3-based OGCM Code (OFES) Optimized for the Earth Simulator
Chapter 1 Atmospheric and Oceanic Simulation Eddy-resolving Simulation of the World Ocean Circulation by using MOM3-based OGCM Code (OFES) Optimized for the Earth Simulator Group Representative Hideharu
More informationComparison Figures from the New 22-Year Daily Eddy Dataset (January April 2015)
Comparison Figures from the New 22-Year Daily Eddy Dataset (January 1993 - April 2015) The figures on the following pages were constructed from the new version of the eddy dataset that is available online
More informationThe role of vorticity fluxes in the dynamics of the Zapiola Anticyclone
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 113,, doi:10.1029/2008jc004841, 2008 The role of vorticity fluxes in the dynamics of the Zapiola Anticyclone Denis L. Volkov 1 and Lee-Lueng Fu 1 Received 31 March
More informationInterannual trends in the Southern Ocean sea surface temperature and sea level from remote sensing data
RUSSIAN JOURNAL OF EARTH SCIENCES, VOL. 9, ES3003, doi:10.2205/2007es000283, 2007 Interannual trends in the Southern Ocean sea surface temperature and sea level from remote sensing data S. A. Lebedev 1,2
More informationEddy-induced meridional heat transport in the ocean
GEOPHYSICAL RESEARCH LETTERS, VOL. 35, L20601, doi:10.1029/2008gl035490, 2008 Eddy-induced meridional heat transport in the ocean Denis L. Volkov, 1 Tong Lee, 1 and Lee-Lueng Fu 1 Received 28 July 2008;
More informationPathways in the ocean
Pathways Pathways in the in the ocean by Sybren Drijfhout Introduction The properties of water masses in the ocean are set by air-sea interactions at the surface and convective overturning. As direct transfer
More informationLecture 4:the observed mean circulation. Atmosphere, Ocean, Climate Dynamics EESS 146B/246B
Lecture 4:the observed mean circulation Atmosphere, Ocean, Climate Dynamics EESS 146B/246B The observed mean circulation Lateral structure of the surface circulation Vertical structure of the circulation
More informationThe influence of mesoscale eddies on the detection of quasi-zonal jets in the ocean
GEOPHYSICAL RESEARCH LETTERS, VOL. 35, L24602, doi:10.1029/2008gl035998, 2008 The influence of mesoscale eddies on the detection of quasi-zonaets in the ocean Michael G. Schlax 1 and Dudley B. Chelton
More informationImproved description of the ocean mesoscale variability by combining four satellite altimeters
Please note that this is an author-produced PDF of an article accepted for publication following peer review. The definitive publisher-authenticated version is available on the publisher Web site GEOPHYSICAL
More informationCHAPTER 7 Ocean Circulation Pearson Education, Inc.
CHAPTER 7 Ocean Circulation 2011 Pearson Education, Inc. Types of Ocean Currents Surface currents Deep currents 2011 Pearson Education, Inc. Measuring Surface Currents Direct methods Floating device tracked
More informationDivergent pathways of cyclonic and anti-cyclonic ocean eddies
GEOPHYSICAL RESEARCH LETTERS, VOL. 31, L24311, doi:10.1029/2004gl020974, 2004 Divergent pathways of cyclonic and anti-cyclonic ocean eddies Rosemary Morrow and Florence Birol Laboratoire d Etudes en Géophysique
More informationSIO 210: Dynamics VI: Potential vorticity
SIO 210: Dynamics VI: Potential vorticity Variation of Coriolis with latitude: β Vorticity Potential vorticity Rossby waves READING: Review Section 7.2.3 Section 7.7.1 through 7.7.4 or Supplement S7.7
More information25-Day Period Large-Scale Oscillations in the Argentine Basin Revealed by the TOPEX/Poseidon Altimeter
506 JOURNAL OF PHYSICAL OCEANOGRAPHY VOLUME 31 25-Day Period Large-Scale Oscillations in the Argentine Basin Revealed by the TOPEX/Poseidon Altimeter LEE-LUENG FU ANDBENNY CHENG Jet Propulsion Laboratory,
More informationOcean and Atmosphere Storm Tracks: The Role of Eddy Vorticity Forcing
SEPTEMBER 2007 W I L L I A M S E T A L. 2267 Ocean and Atmosphere Storm Tracks: The Role of Eddy Vorticity Forcing RICHARD G. WILLIAMS Department of Earth and Ocean Sciences, University of Liverpool, Liverpool,
More informationVariability in the Slope Water and its relation to the Gulf Stream path
Click Here for Full Article GEOPHYSICAL RESEARCH LETTERS, VOL. 35, L03606, doi:10.1029/2007gl032183, 2008 Variability in the Slope Water and its relation to the Gulf Stream path B. Peña-Molino 1 and T.
More informationNon-linear patterns of eddy kinetic energy in the Japan/East Sea
Non-linear patterns of eddy kinetic energy in the Japan/East Sea O.O. Trusenkova, D.D. Kaplunenko, S.Yu. Ladychenko, V.B. Lobanov V.I.Il ichev Pacific Oceanological Institute, FEB RAS Vladivostok, Russia
More informationChapter 3: Ocean Currents and Eddies
Chapter 3: Ocean Currents and Eddies P.Y. Le Traon* and R. Morrow** *CLS Space Oceanography Division, 8-10 rue Hermes, Parc Technologique du Canal, 31526 Ramonville St Agne, France **LEGOS, 14 avenue Edouard
More information1. The figure shows sea surface height (SSH) anomaly at 24 S (southern hemisphere), from a satellite altimeter.
SIO 210 Problem Set 3 November 16, 2015 1. The figure shows sea surface height (SSH) anomaly at 24 S (southern hemisphere), from a satellite altimeter. (a) What is the name of this type of data display?_hovmöller
More informationHYBRID DECADE-MEAN GLOBAL SEA LEVEL WITH MESOSCALE RESOLUTION. University of Hawaii, Honolulu, Hawaii, U.S.A.
HYBRID DECADE-MEAN GLOBAL SEA LEVEL WITH MESOSCALE RESOLUTION Nikolai A. Maximenko 1 and Pearn P. Niiler 2 1 International Pacific Research Center, School of Ocean and Earth Science and Technology, University
More informationEnergetics of a global ocean circulation model compared to observations
GEOPHYSICAL RESEARCH LETTERS, VOL. 38,, doi:10.1029/2011gl048347, 2011 Energetics of a global ocean circulation model compared to observations Prasad G. Thoppil, 1 James G. Richman, 1 and Patrick J. Hogan
More informationUpper Ocean Circulation
Upper Ocean Circulation C. Chen General Physical Oceanography MAR 555 School for Marine Sciences and Technology Umass-Dartmouth 1 MAR555 Lecture 4: The Upper Oceanic Circulation The Oceanic Circulation
More information2/15/2012. Earth System Science II EES 717 Spring 2012
Earth System Science II EES 717 Spring 2012 1. The Earth Interior Mantle Convection & Plate Tectonics 2. The Atmosphere - Climate Models, Climate Change and Feedback Processes 3. The Oceans Circulation;
More informationDo altimeter wavenumber spectra agree with interior or surface. quasi-geostrophic theory?
Do altimeter wavenumber spectra agree with interior or surface quasi-geostrophic theory? P.Y. Le Traon*, P. Klein*, Bach Lien Hua* and G. Dibarboure** *Ifremer, Centre de Brest, 29280 Plouzané, France
More informationC
C 0.8 0.4 0.2 0.0-0.2-0.6 Fig. 1. SST-wind relation in the North Pacific and Atlantic Oceans. Left panel: COADS SST (color shade), surface wind vectors, and SLP regressed upon the Pacific Decadal Oscillation
More informationNorth Atlantic circulation in three simulations of 1/12, 1/25, and 1/50
North Atlantic circulation in three simulations of 1/12, 1/2, and 1/ Xiaobiao Xu and Eric Chassignet Center for ocean-atmospheric prediction studies Florida State University Motivation Numerical models
More informationThe Agulhas Current system: its dynamics and climatic importance
The Agulhas Current system: its dynamics and climatic importance BJØRN BACKEBERG 1 NANSEN-TUTU CENTRE FOR MARINE ENVIRONMENTAL RESEARCH 2 DEPTARTMENT OF OCEANOGRAPHY, UNIVERSITY OF CAPE TOWN Nansen Centers
More informationSIO 210: Dynamics VI (Potential vorticity) L. Talley Fall, 2014 (Section 2: including some derivations) (this lecture was not given in 2015)
SIO 210: Dynamics VI (Potential vorticity) L. Talley Fall, 2014 (Section 2: including some derivations) (this lecture was not given in 2015) Variation of Coriolis with latitude: β Vorticity Potential vorticity
More informationMean Stream-Coordinate Structure of the Kuroshio Extension First Meander Trough
Mean Stream-Coordinate Structure of the Kuroshio Extension First Meander Trough 6 March, 2008 Penelope J. Howe, Kathleen A. Donohue, and D. Randolph Watts Graduate School of Oceanography University of
More informationWind Gyres. curl[τ s τ b ]. (1) We choose the simple, linear bottom stress law derived by linear Ekman theory with constant κ v, viz.
Wind Gyres Here we derive the simplest (and oldest; Stommel, 1948) theory to explain western boundary currents like the Gulf Stream, and then discuss the relation of the theory to more realistic gyres.
More informationSurface Circulation. Key Ideas
Surface Circulation The westerlies and the trade winds are two of the winds that drive the ocean s surface currents. 1 Key Ideas Ocean water circulates in currents. Surface currents are caused mainly by
More informationComparison of Sea Surface Heights Observed by TOPEX Altimeter with Sea Level Data at Chichijima
Journal of Oceanography Vol. 52, pp. 259 to 273. 1996 Comparison of Sea Surface Heights Observed by TOPEX Altimeter with Sea Level Data at Chichijima NAOTO EBUCHI 1 and KIMIO HANAWA 2 1 Center for Atmospheric
More informationNOTES AND CORRESPONDENCE. On Sverdrup Discontinuities and Vortices in the Southwest Indian Ocean
2940 J O U R N A L O F P H Y S I C A L O C E A N O G R A P H Y VOLUME 37 NOTES AND CORRESPONDENCE On Sverdrup Discontinuities and Vortices in the Southwest Indian Ocean J. H. LACASCE Institute for Geophysics,
More informationUpper ocean temperature and the baroclinic transport stream function relationship in Drake Passage
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 109,, doi:10.1029/2003jc002010, 2004 Upper ocean temperature and the baroclinic transport stream function relationship in Drake Passage Serguei Sokolov, 1 Brian A.
More informationJOURNAL OF GEOPHYSICAL RESEARCH, VOL. 106, NO. C9, PAGES 19,581-19,595, SEPTEMBER 15, 2001
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 106, NO. C9, PAGES 19,581-19,595, SEPTEMBER 15, 2001 Mesoscale characteristics G. A. Jacobs, C. N. Barron, and R. C. Rhodes Naval Research Laboratory, Stennis Space
More informationOn the formation of Subtropical Countercurrent to the west of the Hawaiian Islands
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 108, NO. C5, 3167, doi:10.1029/2002jc001366, 2003 On the formation of Subtropical Countercurrent to the west of the Hawaiian Islands Qinyu Liu, Shaoxia Wang, Qi Wang,
More informationSatellite Altimetry Sea Surface Height Variability and In Situ Observations Along An Eddy Corridor Dr. Sheekela Baker-Yeboah 1
Satellite Altimetry Sea Surface Height Variability and In Situ Observations Along An Eddy Corridor Dr. Sheekela Baker-Yeboah 1 NOAA/NESDIS/National Center for Environmental Information, 2 University of
More informationOcean currents from altimetry
Ocean currents from altimetry Pierre-Yves LE TRAON - CLS - Space Oceanography Division Gamble Workshop - Stavanger,, May 2003 Introduction Today: information mainly comes from in situ measurements ocean
More informationsensors ISSN by MDPI
Sensors 26, 6, 235-248 sensors ISSN 1424-822 26 by MDPI http://www.mdpi.org/sensors Special Issue on Satellite Altimetry: New Sensors and New Application Edited by Ge Chen and Graham D. Quartly Full Research
More informationEddy Dynamics From. The Future of Oceanography From Space. Oceanography Vol. 23, No.4
Oceanography The Official MAGAzINE OF THE OCEANOGRAPHY SOCIETY CITATION Fu, L.-L., D.B. Chelton, P.-Y. Le Traon, and R. Morrow. 2010. Eddy dynamics from satellite altimetry. Oceanography 23(4):14 25, doi:10.5670/oceanog.2010.02.
More informationVertical velocities in the upper ocean from glider and altimetry data 1
Vertical velocities in the upper ocean from glider and altimetry data 1 In this poster we show results on the combination of new glider technology data with altimetry observations to diagnose vertical
More informationFlow structure and variability in the Subtropical Indian Ocean
Chapter 4 Flow structure and variability in the Subtropical Indian Ocean 4.1 Introduction It is well known from satellite altimetry that the variability of the South Indian Ocean comprises a range of frequencies
More informationIs there a continuous Subtropical Front south of Africa?
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 116,, doi:10.1029/2010jc006587, 2011 Is there a continuous Subtropical Front south of Africa? Guillaume Dencausse, 1,2 Michel Arhan, 1 and Sabrina Speich 1 Received
More informationArnold L. Gordon Retroflections and Bifurcations Johann Lutjeharms Memorial Lecture
The Agulhas System and its Role in Changing Ocean Circulation, Climate & Marine Ecosystems Spier Hotel, Stellenbosch, Western Cape, South Africa 8 12 October 2012 Brazil/Malvinas Agulhas Retroflection
More informationClimate Change Research Centre
2S On Agulhas rings and leakage (and whether it all matters) All trajectories of observational Agulhas buoys 3S 4S Erik van Sebille 1E 2E 3E 4E With input from Lisa Beal, Arne Biastoch, Matthew England,
More information3. Midlatitude Storm Tracks and the North Atlantic Oscillation
3. Midlatitude Storm Tracks and the North Atlantic Oscillation Copyright 2006 Emily Shuckburgh, University of Cambridge. Not to be quoted or reproduced without permission. EFS 3/1 Review of key results
More informationSurface winds, divergence, and vorticity in stratocumulus regions using QuikSCAT and reanalysis winds
GEOPHYSICAL RESEARCH LETTERS, VOL. 31, L08105, doi:10.1029/2004gl019768, 2004 Surface winds, divergence, and vorticity in stratocumulus regions using QuikSCAT and reanalysis winds B. D. McNoldy, P. E.
More informationWestern Boundary Currents. Global Distribution of Western Boundary Currents and their importance
Western Boundary Currents In previous chapters you have learned about the processes that cause the intensification of currents along the western boundaries of the oceans. In this chapter we will examine
More informationEstimation of the Agulhas ring impacts on meridional heat fluxes and transport using ARGO floats and satellite data
GEOPHYSICAL RESEARCH LETTERS, VOL. 38,, doi:10.1029/2011gl049359, 2011 Estimation of the Agulhas ring impacts on meridional heat fluxes and transport using ARGO floats and satellite data J. M. A. C. Souza,
More information1 The satellite altimeter measurement
1 The satellite altimeter measurement In the ideal case, a satellite altimeter measurement is equal to the instantaneous distance between the satellite s geocenter and the ocean surface. However, an altimeter
More informationS11. Indian Ocean: Supplementary Materials
C H A P T E R S11 Indian Ocean: Supplementary Materials FIGURE S11.1 Indian Ocean surface circulation (Tables S11.1, S11.2 and Figure 11.1). Surface height (cm). Data from Niiler, Maximenko, and McWilliams
More informationChapter 6. Antarctic oceanography
Chapter 6 Antarctic oceanography The region of the world ocean bordering on Antarctica is unique in many respects. First of all, it is the only region where the flow of water can continue all around the
More informationOcean and atmosphere storm tracks: the role of eddy vorticity forcing
Ocean and atmosphere storm tracks: the role of eddy vorticity forcing Richard G. Williams 1, Chris Wilson 1,2, and Chris W. Hughes 2 1. Department of Earth and Ocean Sciences, University of Liverpool,
More informationCoastal Ocean Circulation Experiment off Senegal (COCES)
DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Coastal Ocean Circulation Experiment off Senegal (COCES) Pierre-Marie Poulain Istituto Nazionale di Oceanografia e di Geofisica
More informationApplications of an ensemble Kalman Filter to regional ocean modeling associated with the western boundary currents variations
Applications of an ensemble Kalman Filter to regional ocean modeling associated with the western boundary currents variations Miyazawa, Yasumasa (JAMSTEC) Collaboration with Princeton University AICS Data
More informationA simple predictive model for the eddy propagation. trajectory in the South China Sea
1 2 3 4 A simple predictive model for the eddy propagation trajectory in the South China Sea Jiaxun Li 1,2, Guihua Wang *1, Huijie Xue 3,4, and Huizan Wang 5 5 6 7 8 9 10 11 12 13 1 Department of Atmospheric
More informationCoupling of Extratropical Mesoscale Eddies in the Ocean to Westerly Winds in the Atmospheric Boundary Layer
1095 Coupling of Extratropical Mesoscale Eddies in the Ocean to Westerly Winds in the Atmospheric Boundary Layer WARREN B. WHITE AND JEFFREY L. ANNIS Scripps Institution of Oceanography, University of
More informationThermohaline and wind-driven circulation
Thermohaline and wind-driven circulation Annalisa Bracco Georgia Institute of Technology School of Earth and Atmospheric Sciences NCAR ASP Colloquium: Carbon climate connections in the Earth System Tracer
More informationCoastal Ocean Modeling & Dynamics - ESS
DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Coastal Ocean Modeling & Dynamics - ESS Roger M. Samelson College of Earth, Ocean, and Atmospheric Sciences Oregon State
More informationSIO 210 Final examination Answer Key for all questions except Daisyworld. Wednesday, December 10, PM Name:
SIO 210 Final examination Answer Key for all questions except Daisyworld. Wednesday, December 10, 2008 3-6 PM Name: This is a closed book exam. You may use a calculator. There are two parts: Talley (weighted
More informationCircumpolar structure and distribution of the Antarctic Circumpolar Current fronts: 1. Mean circumpolar paths
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 114,, doi:10.1029/2008jc005108, 2009 Circumpolar structure and distribution of the Antarctic Circumpolar Current fronts: 1. Mean circumpolar paths Serguei Sokolov
More informationResponse of the Antarctic Circumpolar Current to Atmospheric Variability
3020 J O U R N A L O F C L I M A T E VOLUME 21 Response of the Antarctic Circumpolar Current to Atmospheric Variability J. B. SALLÉE LEGOS, Toulouse, France K. SPEER Oceanography Department, The Florida
More informationCold air outbreak over the Kuroshio Extension Region
Cold air outbreak over the Kuroshio Extension Region Jensen, T. G. 1, T. Campbell 1, T. A. Smith 1, R. J. Small 2 and R. Allard 1 1 Naval Research Laboratory, 2 Jacobs Engineering NRL, Code 7320, Stennis
More informationActive microwave systems (2) Satellite Altimetry * the movie * applications
Remote Sensing: John Wilkin wilkin@marine.rutgers.edu IMCS Building Room 211C 732-932-6555 ext 251 Active microwave systems (2) Satellite Altimetry * the movie * applications Altimeters (nadir pointing
More informationTransport driven by eddy momentum fluxes in the Gulf Stream Extension region
GEOPHYSICAL RESEARCH LETTERS, VOL. 37,, doi:10.1029/2010gl045473, 2010 Transport driven by eddy momentum fluxes in the Gulf Stream Extension region R. J. Greatbatch, 1 X. Zhai, 2 M. Claus, 1 L. Czeschel,
More informationNonlinear vorticity balance of the Antarctic Circumpolar Current
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 110,, doi:10.1029/2004jc002753, 2005 Nonlinear vorticity balance of the Antarctic Circumpolar Current Chris W. Hughes Proudman Oceanographic Laboratory, Liverpool,
More informationOn the Transition from Profile Altimeter to Swath Altimeter for Observing Global Ocean Surface Topography
560 J O U R N A L O F A T M O S P H E R I C A N D O C E A N I C T E C H N O L O G Y VOLUME 31 On the Transition from Profile Altimeter to Swath Altimeter for Observing Global Ocean Surface Topography LEE-LUENG
More informationSIO 210 Final examination Wednesday, December 12, :30-2:30 Eckart 227 Name:
SIO 210 Final examination Wednesday, December 12, 2018 11:30-2:30 Eckart 227 Name: Please put your initials or name on each page, especially if you pull pages apart. Turn off all phones, ipods, etc. and
More informationSAMPLE CHAPTERS UNESCO EOLSS SYNOPTIC/MESOSCALE PROCESSES. John M. Huthnance Proudman Oceanographic Laboratory, U.K.
SYNOPTIC/MESOSCALE PROCESSES John M. Huthnance Proudman Oceanographic Laboratory, U.K. Keywords : Advection, Diffusivity, Distribution, Dynamics, Eddy, Energy, Mesoscale, Nutrients, Plankton, Propagation,
More informationOn the world-wide circulation of the deep water from the North Atlantic Ocean
Journal of Marine Research, 63, 187 201, 2005 On the world-wide circulation of the deep water from the North Atlantic Ocean by Joseph L. Reid 1 ABSTRACT Above the deeper waters of the North Atlantic that
More informationSUPPLEMENTARY INFORMATION
In the format provided by the authors and unedited. SUPPLEMENTARY INFORMATION DOI: 10.1038/NGEO3053 1 2 Contribution of topographically-generated submesoscale turbulence to Southern Ocean overturning 3
More informationOcean Color: Currents and Productivity
Ocean Color: Currents and Productivity Name This assignment is worth 20 points! Your textbook describes the basic properties of light and its interaction with water and the oceans (p. 374-376). What is
More informationSalinity variability associated with changes in the hydrological cycle variables
Salinity variability associated with changes in the hydrological cycle variables Olga Sato Paulo Polito olga.sato@usp.br Oceanographic Institute of the University of SÃčo Paulo Olga Sato (IOUSP) Salinity
More informationPathways of the Greenland Sea warming
GEOPHYSICAL RESEARCH LETTERS, VOL. 34, L10608, doi:10.1029/2007gl029974, 2007 Pathways of the Greenland Sea warming Waldemar Walczowski 1 and Jan Piechura 1 Received 12 March 2007; revised 23 April 2007;
More informationOcean Mixing and Climate Change
Ocean Mixing and Climate Change Factors inducing seawater mixing Different densities Wind stirring Internal waves breaking Tidal Bottom topography Biogenic Mixing (??) In general, any motion favoring turbulent
More informationCirculation in the South China Sea in summer of 1998
Circulation in the South China Sea in summer of 1998 LIU Yonggang, YUAN Yaochu, SU Jilan & JIANG Jingzhong Second Institute of Oceanography, State Oceanic Administration (SOA), Hangzhou 310012, China;
More informationOn the fast decay of Agulhas rings
Click Here for Full Article JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 115,, doi:10.1029/2009jc005585, 2010 On the fast decay of Agulhas rings Erik van Sebille, 1,2 Peter Jan van Leeuwen, 1,3 Arne Biastoch,
More informationUC Irvine Faculty Publications
UC Irvine Faculty Publications Title A linear relationship between ENSO intensity and tropical instability wave activity in the eastern Pacific Ocean Permalink https://escholarship.org/uc/item/5w9602dn
More informationCHAPTER 9 ATMOSPHERE S PLANETARY CIRCULATION MULTIPLE CHOICE QUESTIONS
CHAPTER 9 ATMOSPHERE S PLANETARY CIRCULATION MULTIPLE CHOICE QUESTIONS 1. Viewed from above in the Northern Hemisphere, surface winds about a subtropical high blow a. clockwise and inward. b. counterclockwise.
More informationDecadal Variation of the Geostrophic Vorticity West of the Luzon Strait
144 The Open Oceanography Journal, 2010, 4, 144-149 Open Access Decadal Variation of the Geostrophic Vorticity West of the Luzon Strait Yinglai Jia *,1, Qinyu Liu 1 and Haibo Hu 2 1 Physical Oceanography
More informationClimate Variability Studies in the Ocean
Climate Variability Studies in the Ocean Topic 1. Long-term variations of vertical profiles of nutrients in the western North Pacific Topic 2. Biogeochemical processes related to ocean carbon cycling:
More informationGeneral Comment on Lab Reports: v. good + corresponds to a lab report that: has structure (Intro., Method, Results, Discussion, an Abstract would be
General Comment on Lab Reports: v. good + corresponds to a lab report that: has structure (Intro., Method, Results, Discussion, an Abstract would be a bonus) is well written (take your time to edit) shows
More informationFlow structure and variability in the subtropical Indian Ocean: Instability of the South Indian Ocean Countercurrent
Click Here for Full Article JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 112,, doi:10.1029/2005jc003395, 2007 Flow structure and variability in the subtropical Indian Ocean: Instability of the South Indian Ocean
More informationThe Planetary Circulation System
12 The Planetary Circulation System Learning Goals After studying this chapter, students should be able to: 1. describe and account for the global patterns of pressure, wind patterns and ocean currents
More informationAn Automated Approach to Detect Oceanic Eddies from Satellite Remote Sensed Sea Surface Temperature Data
An Automated Approach to Detect Oceanic Eddies from Satellite Remote Sensed Sea Surface Temperature Data Changming Dong 1 Francesco Nencioli 2 Yu Liu 3,4 James C. McWilliams 1 1 Institute of Geophysics
More informationActual bathymetry (with vertical exaggeration) Geometry of the ocean 1/17/2018. Patterns and observations? Patterns and observations?
Patterns and observations? Patterns and observations? Observations? Patterns? Observations? Patterns? Geometry of the ocean Actual bathymetry (with vertical exaggeration) Continental Continental Basin
More informationLecture 1. Amplitude of the seasonal cycle in temperature
Lecture 6 Lecture 1 Ocean circulation Forcing and large-scale features Amplitude of the seasonal cycle in temperature 1 Atmosphere and ocean heat transport Trenberth and Caron (2001) False-colour satellite
More informationRegional Oceanography: an Introduction
64 Regional Oceanography: an Introduction 2500 m depth, or 10-30% of the speeds observed at the 500 m level. It is therefore easy to see why the Circumpolar Current has the largest mass transport of all
More informationElsevier Editorial System(tm) for Deep-Sea Research Part II Manuscript Draft
Elsevier Editorial System(tm) for Deep-Sea Research Part II Manuscript Draft Manuscript Number: Title: Circulation, stratification and seamounts in the South West Indian Ocean Article Type: SW Indian Ocean
More informationObservations and Modeling of SST Influence on Surface Winds
Observations and Modeling of SST Influence on Surface Winds Dudley B. Chelton and Qingtao Song College of Oceanic and Atmospheric Sciences Oregon State University, Corvallis, OR 97331-5503 chelton@coas.oregonstate.edu,
More informationArne Biastoch Helmholtz Centre for Ocean Research Kiel. Modelling the Agulhas Current and its Coupling with the Atlantic Circulation
Arne Biastoch Helmholtz Centre for Ocean Research Kiel Modelling the Agulhas Current and its Coupling with the Atlantic Circulation The Agulhas System as a Key Region of the Global Oceanic Circulation
More informationScotian Slope circulation and eddy variability from TOPEX/Poseidon and frontal analysis data
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 109,, doi:10.1029/2003jc002046, 2004 Scotian Slope circulation and eddy variability from TOPEX/Poseidon and frontal analysis data Guoqi Han Northwest Atlantic Fisheries
More informationObservation and modeling of eddies and dipoles in the Southern Indian Ocean
Observation and modeling of eddies and dipoles in the Southern Indian Ocean Yana Bebieva 1 Utrecht University 19.06.2013 Abstract Analysis of the along track satellite data near the southern tip of Madagascar
More informationCurrents and Mixing in the Southern Ocean. Sarah Gille
Currents and Mixing in the Southern Ocean Sarah Gille Scripps Institution of Oceanography and Department of Mechanical and Aerospace Engineering UCSD, La Jolla, CA Where might AVISO gridded fields fall
More informationEddy and Chlorophyll-a Structure in the Kuroshio Extension Detected from Altimeter and SeaWiFS
14th Symposium on Integrated Observing and Assimilation Systems for the Atmosphere, Oceans, and Land Surface (IOAS-AOLS), AMS Atlanta, January 17-21, 21 Eddy and Chlorophyll-a Structure in the Kuroshio
More informationHow Topographic Smoothing Contributes to Differences between the Eddy Flows Simulated by Sigma- and Geopotential-Coordinate Models
122 JOURNAL OF PHYSICAL OCEANOGRAPHY VOLUME 32 How Topographic Smoothing Contributes to Differences between the Eddy Flows Simulated by Sigma- and Geopotential-Coordinate Models THIERRY PENDUFF Center
More informationSST Observations of the Agulhas and East Madagascar Retroflections by the TRMM Microwave Imager
MAY 2002 NOTES AND CORRESPONDENCE 1585 SST Observations of the Agulhas and East Madagascar Retroflections by the TRMM Microwave Imager GRAHAM D. QUARTLY AND MERIC A. SROKOSZ James Rennell Division for
More informationAnticyclonic Eddy Revealing Low Sea Surface Temperature in the Sea South of Japan: Case Study of the Eddy Observed in
Journal of Oceanography, Vol. 6, pp. 663 to 671, 4 Anticyclonic Eddy Revealing Low Sea Surface Temperature in the Sea South of Japan: Case Study of the Eddy Observed in 1999 KOHTARO HOSODA 1 * and KIMIO
More information