OCS Study 

MMS 2010-001 

 

Proceedings: USA-Mexico Workshop 

on the Deepwater Physical Oceanography 

of the Gulf of Mexico 

June 2007 

U.S. Department of the Interior

Minerals Management Service 

Gulf of Mexico OCS Region 
OCS Study 

MMS 2010-001 

Proceedings: USA-Mexico Workshop 

on the Deepwater Physical Oceanography 

of the Gulf of Mexico 

June 2007 

Editors 

Christopher N.K. Mooers 

Alexis Lugo-Fernández 

Prepared under MMS Contract 

1435-00-01-CA-39526 (M05AC12281) 

by 

University of New Orleans 

Office of Conference Services 

New Orleans, Louisiana 70814 

Published by 

U.S. Department of the Interior 

Minerals Management Service 

Gulf of Mexico OCS Region 

New Orleans

January 2010 
iii 

DISCLAIMER

This report was prepared under contract between the Minerals Management Service (MMS) and 

the University of New Orleans, Office of Conference Services. This report has been technically 

reviewed by the MMS and it has been approved for publication. Approval does not signify that 

the contents necessarily reflect the views and policies of the MMS, nor does mention of trade 

names or commercial products constitute endorsement or recommendation for use. It is, 

however, exempt from review and compliance with MMS editorial standards. 

REPORT AVAILABILITY

This report is available only in compact disc format from the Minerals Management Service, 

Gulf of Mexico OCS Region, at a charge of $15.00, by referencing OCS Study MMS 2010-001. 

The report may be downloaded from the MMS website through the Environmental Studies 

Information System (ESPIS). You will be able to obtain this report also from the National 

Technical Information Service in the near future. Here are the addresses. You may also inspect 

copies at the Federal Depository Libraries. 

Minerals Management Service 

Gulf of Mexico OCS Region 

Public Information Office (MS 5034) 

1201 Elmwood Park Boulevard 

New Orleans, Louisiana 70123-2394 

Telephone requests may be placed at 

(504) 736-2519, 1-800-200-GULF, or 

Rush Orders: 1-800-553-6847 

Fax: (504) 736-2620 

U.S. Department of Commerce 

National Technical Information Service 

5285 Port Royal Road 

Springfield, Virginia 22161 

Phone: (703) 605-6040 

Fax: (703) 605-6900 

Email: bookstore@ntis.gov 

CITATION

This study should be cited as: 

Mooers, C.N.K. and A. Lugo-Fernández, eds. 2009. Proceedings: USA-Mexico workshop on the 

deepwater physical oceanography of the Gulf of Mexico, June 2007. U.S. Dept. of the 

Interior, Minerals Management Service, Gulf of Mexico OCS Region, New Orleans, LA. 

OCS Study MMS 2010-001. 158 pp. 
v 

TABLE OF CONTENTS 

Page

LIST OF FIGURES ...................................................................................................................... vii 

LIST OF TABLES......................................................................................................................... ix 

EXECUTIVE SUMMARY ........................................................................................................... xi 

INTRODUCTION .......................................................................................................................xiii 

PROGRAM................................................................................................................................... xv 

PEMEX’S METOCEANIC PLANS FOR THE GULF OF MÉXICO 

Guillermo Pérez Cruz ..................................................................................................................... 1 

MMS OBJECTIVES & EXPECTATIONS FOR U.S.–MEXICO DEEPWATER 

WORKSHOP Alexis Lugo-Fernández .......................................................................................... 7 

AN OVERVIEW OF DEEP CIRCULATION PROCESSES IN THE GULF USING 

MOORED AND LAGRANGIAN OBSERVATIONS Peter Hamilton ...................................... 13 

PRESSURE-RECORDING INVERTED ECHO SOUNDER (PIES) STUDIES IN 

THE GULF OF MEXICO Kathleen Donohue and D. Randolph Watts...................................... 33 

CANEK: 10 YEARS OF OCEANOGRAPHIC OBSERVATIONS IN THE CARIBBEAN 

SEA AND GULF OF MEXICO Julio Candela, J. Sheinbaum, J. Ochoa, and A. Badan............ 57 

UPPER LAYER SUBSURFACE JETS AND INERTIAL CURRENTS IN THE 

NORTHERN GULF Peter Hamilton........................................................................................... 79 

IASNFS: AN OPERATIONAL REAL-TIME NOWCAST/FORECAST SYSTEM FOR 

INTRA-AMERICAS SEA Dong S. Ko....................................................................................... 95 

NEW MEASUREMENT TECHNOLOGIES AND DATA ANALYSIS TECHNIQUES 

John Toole................................................................................................................................... 107 

BREAKOUT SESSION SUMMARIES..................................................................................... 131 

OBSERVATIONAL PLANS AND NEEDS FOR MODELING INFORMATION 

IN USA AND MEXICAN WATERS (S-1 & S-3)......................................................... 131 

MODELING PLANS AND NEEDS FOR OBSERVATIONAL INFORMATION 

IN USA AND MEXICAN WATERS (S-2 & S-4)......................................................... 134 

RECOMMENDATIONS............................................................................................................ 143 
vi 

APPENDIX I: IMPORTANT METRICS FOR GULF OF MEXICO MODEL SKILL 

ASSESSMENTS................................................................................................. 145 

APPENDIX II: KEY OBSERVATIONAL DATA SETS AVAILABLE FOR MODEL 

SKILL ASSESSMENTS................................................................................... 147 

ACRONYMS.............................................................................................................................. 149 

INDEX TO AUTHORS.............................................................................................................. 151 

ATTENDEES ............................................................................................................................. 153 
vii 

LIST OF FIGURES 

Page

Figure 1. Mean (top) and standard deviation ellipses (bottom) of 40-HLP currents at 100 

to 500-m above the bottom from recent MMS studies (see text). ...............................14 

Figure 2. Smoothed lagrangian drifter tracks from two Exploratory RAFOS floats at 

1500 m. ........................................................................................................................16 

Figure 3. Smoothed track of RAFOS float RFS0490 at 2000 m for the indicated time 

interval. ........................................................................................................................17 

Figure 4. Kinetic eddy spectra in variance preserving form for the near-bottom current 

records across the center of the Gulf............................................................................18 

Figure 5. Map of the three MMS-sponsored arrays of pressure-recording inverted echo 

sounders (PIES, blue dots), and current meter moorings (red dots) deployed 

in the northern Gulf of Mexico. ...................................................................................33 

Figure 6. Surface and deep eddy kinetic energy determined from the three PIES arrays 

in the northern Gulf of Mexico. ...................................................................................35 

Figure 7. Case study of a lower-layer cyclone leading an upper-ocean cyclone [30 July – 

05 August 2005] as the crest of the Loop Current withdraws southeastward in 

the Northeast Gulf array...............................................................................................36 

Figure 8. Potential vorticity terms are diagnosed as time series at the location within the 

Northeast Gulf array indicated by the red star.............................................................37 

Figure 9. RH panels show the kinetic energy spectra, in variance preserving form, for 

currents at 3 depths at U3 and U4 moorings................................................................80 

Figure 10. Unfiltered speed from the 450 m ADCP at T5 for the indicated interval....................81 

Figure 11. 1-day mean 3-HLP temperature at 150 m and currents at selected depths for 

26 February 2005, 0000 GMT. ....................................................................................82 

Figure 12. Observational array configurations discussed. A) Hamilton/SAIC suggested 

array configuration including over two dozen PIES as well as moorings. 

B) Some of the currently operational (red) and historical (green) locations 

of Mexican moorings. C) Lugo-Fernández/MMS suggested mooring array 

configuration..............................................................................................................140 
ix 

LIST OF TABLES 

Page

Table 1. Major Scientific Questions ........................................................................................135 

Table 2. Attributes of Modeling Program................................................................................136 

Table 3. Attributes of Observations Needed in Support of Models.........................................138 
xi 

EXECUTIVE SUMMARY 

The MMS has led the USA’s physical oceanography studies of the Gulf of Mexico for over 30 

years. Consequently, observational and numerical modeling studies of the Gulf of Mexico 

circulation have advanced rapidly. Now the challenge is to pursue, together with Mexican 

colleagues, progressive, coordinated observational and modeling studies of the deep Gulf of 

Mexico. 

Accordingly, fifty-seven American and seven Mexican colleagues gathered for two and one-half 

days in June 2007 to review the present understanding of the deepwater physical oceanography 

of the Gulf of Mexico, and to consider scientific, technological, and logistical opportunities to 

further advance that understanding. For example, recent time series results from moored current 

meter arrays and satellite radar altimetric sea surface height maps, on one hand, and numerical 

simulations of the Gulf’s circulation, on the other hand, were presented, suggesting a high 

potential for better integrated modeling and observational studies in the near future. Further, 

newly developed instrumentation for free-fall or autonomous vertical profiling observations, as 

proven in other regions of the ocean, were introduced for potential application in future Gulf 

studies. A combination of invited plenary talks, participatory breakout groups, and final plenary 

discussions was used to develop a consensus. To focus the deliberations, a proposed 

MMS/PEMEX Gulf of Mexico Long-Term (viz., decadal) Goal was interjected: Establish a 

scientifically credible Gulf of Mexico (model-based) analysis/re-analysis system that will 

foster and facilitate diagnostic studies of the circulation and related topics. 

Such a long-term goal immediately gives rise to several questions; e.g., 

 1. What process and sensitivity studies are needed? 

 2. What observing subsystem network design strategy is needed? 

 3. What modeling subsystem validation and verification strategies are needed? 

These and related questions led to the consideration of metrics for the assessment of model skill, 

and, for that matter, of observing network adequacy. The potential scientific and pragmatic value 

is high for strongly coordinated (i.e., more than has been the case heretofore) observational and 

modeling studies, involving both American and Mexican colleagues, focused on the long-term 

goal of evolving a circulation analysis/re-analysis capability for the circulation of the Gulf of 

Mexico and its application to ecosystem and other studies. 
xiii 

INTRODUCTION 

The activities of the offshore oil & gas industry in the Gulf of Mexico have intensified and 

extended further offshore in recent decades, creating new challenges for marine resource and 

environmental management and new opportunities for marine scientific research. These 

opportunities include the study of the circulation of the Gulf of Mexico in its full glory of 

powerful mean current jets, fronts, and mesoscale eddies and their interactions with steep bottom 

topography; the Mississippi-Atchafalaya River plume; and the passage of tropical cyclones in the 

summer and cold fronts in the winter. Observations and numerical modeling of the Gulf’s 

circulation suggest that observations and models must be linked to generate sound estimates of 

the spatially complex and temporally variable circulation. American and Mexican offshore oil & 

gas exploration and production has spread from the inner continental shelf regions to the 

continental slope and now to the deep Gulf. In recent years, both American and Mexican 

scientific investigations of the circulation have extended into deeper waters, too. Hence, 

American and Mexican offshore industries, environmentalists, and research scientists share an 

interest in a comprehensive description, understanding, and predictive capability for the Gulf 

circulation. With both the USA and Mexico planning further extensive field and modeling 

studies in the near-future, it was thought timely to conduct a workshop to discuss recent results 

and coordinate plans, with the hope that more of the space-time variability could be 

characterized than otherwise would be possible by either country alone. 
xv 

PROGRAM 

26 JUNE 2007 

0730 Breakfast 

0800 Prof. Chris Mooers, RSMAS/UM 

 Opening Remarks 

0805 Dr. Guillermo Pérez Cruz, PEMEX 

 Pemex ́s Metoceanic Plans for the Gulf of Mexico

0820 Dr. Alexis Lugo-Fernández, MMS 

 MMS Objectives and Expectations

Invited Talks

0830 Dr. Peter Hamilton, SAIC 

 An Overview of Deep Circulation Processes in the Gulf Using Moored 

 and Lagrangian Observations 

0855 Drs. Randy Watts and Kathy Donohue, URI 

 Synthesis of Bottom Pressure/Inverted Echo Sounder (PIES) Data 

 from MMS Studies in the Gulf of Mexico 

0940 Dr. Leo Oey, PU 

 A Modeler’s Quest to Probe the Deep Unknowns 

1025 Break 

1040 Dr. Julio Candela, CICESE

 CANEK: Ten Years of Current Measurements in the Northwestern Caribbean 

1120 Dr. Julio Sheinbaum, CICESE 

 Numerical Models of the Gulf of Mexico and Caribbean Sea: the CICESE 

 Experience 

1200 Lunch 

1300 Dr. Robert Leben, CU

 Upper Ocean Circulation in the Gulf of Mexico Deepwater: A Remote 

 Sensing Perspective 

1415 Dr. Peter Hamilton, SAIC

 Upper Layer Subsurface Jets and Inertial Currents in the Northern Gulf 
xvi 

1440 Dr. Dong-Shan Ko, NRL 

 IAS/NFS: An Operational Nowcast/Forecast System for the Intra-Americas 

 Sea (IAS) 

0315 Break 

0330 Dr. John Toole, WHOI 

 New Technologies/Approaches (w/audience participation) 

1630 General Discussion Led by Chair and Co-Chairs 

1715 Organization of Breakout Sessions (Chair) 

1730 Adjourn 

27 JUNE 2007 

0800 Breakfast 

0830 First Breakout Sessions 

 S-1 Observational Plans and Needs for Modeling Information in USA Waters 

 (Co-Chairs, Steven DiMarco, TAMU and Antonio Badan, CICESE; 

 Rapporteur, Walter Johnson, MMS) 

 S-2 Modeling Plans and Needs for Observational Information in USA Waters 

 (Co-Chairs, Robert Weisberg, USF and Julio Sheinbaum, CICESE; 

 Rapporteur, Carole Current, MMS) 

1000 Break 

1030 S-1 and S-2 (continued) 

1200 Lunch 

1330 Second Breakout Sessions 

 S-3 Observational Plans and Needs for Modeling Information in Mexican Waters 

 (Co-Chairs, Antonio Badan, CICESE and Steven DiMarco, TAMU; 

 Rapporteur, Walter Johnson, MMS) 

 S-4 Modeling Plans and Needs for Observational Information in Mexican Waters 

 (Co-Chairs, Julio Sheinbaum, CICESE and Robert Weisberg, USF; 

 Rapporteur, Carole Current, MMS) 

1500 Break 

1530 S-3 and S-4 (continued) 

1700 Adjourn 

1730 “Social Hour”
xvii 

28 JUNE 2007 

0800 Breakfast 

0830 Breakout Session Summaries (Co-Chairs and Rapporteurs) 

1000 Break 

1030 Overall Summary/Follow-up Plans (Chair and Co-Chairs; Rapporteurs, 

 Carole Current) 

 (Workshop report with studies recommendations/short report for 

 OS/etc.)

1200 Adjourn 

1200 to 1400 Lunch meeting for Convener, Chair, Co-Chairs, Rapporteurs, et al. 

 to plan follow-up
INDIVIDUAL PRESENTATIONS 

PEMEX’S METOCEANIC PLANS FOR THE GULF OF MÉXICO 

Guillermo Pérez Cruz, Pemex 

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6 
MMS OBJECTIVES & EXPECTATIONS FOR U.S.-MEXICO 

DEEPWATER WORKSHOP 

Alexis Lugo-Fernández, Minerals Management Service 

 

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13 

AN OVERVIEW OF DEEP CIRCULATION PROCESSES IN THE GULF USING 

MOORED AND LAGRANGIAN OBSERVATIONS 

Peter Hamilton, Science Applications International Corporation 

Introduction 

The database of deep current observations has had recent major additions from several MMS 

studies over the lower slopes and abyssal depths of the northern Gulf. The mooring positions are 

given by the dots in Figure 1 with the indicated studies being the Eastern Gulf (E: 4 moorings, 

January 2005 – January 2006), Exploratory Program (X: 19 moorings, March 2003 – April 

2004), Northwestern Gulf (W: 13 moorings, April 2004 – June 2005), Mexican sector (C: 1 

mooring in the central Gulf, May 2003 – August 2004, and 5 moorings in the western Gulf, 

September 2004 – November 2005), and Western Loop Current (L: 1 mooring, April 2003 – 

June 2004). The exploratory program also deployed deep RAFOS Lagrangian floats at depths 

below 1000 m. In the central and western Gulf, the moorings have shown that there are bottom 

intensified low-frequency fluctuations with periods of ~ 10 to 60 days that are highly coherent in 

the vertical for depths greater than ~ 800 – 1200 m. These motions are characteristic of 

Topographic Rossby waves (TRWs) as shown by Hamilton (1990), Hamilton and LugoFernández (2001), and Hamilton (2007). Analyzed wavelengths are generally in the range of 

~ 70 to 200 km and group speeds of order 10 to 20 cm/s are prevalent. Modeling studies (Oey 

and Lee 2002) indicate that energetic fluctuations in the lower layer are generated by Loop 

Current (LC) fluctuations, and also westward translating anticyclones (LC eddies) shed from the 

LC. However, the mechanisms for the generation of TRWs by the LC or LC eddies have not yet 

been clearly observed or elucidated from model and theoretical studies. Model studies have also 

shown that westward translating LC eddies may generate a companion lower-layer 

cyclone/anticyclone pair that remain coherent into the far western Gulf (Welsh and Inoue 2000). 

These lower layer eddy-like circulations have not yet been observed, and present indications 

from the observations are that if such deep eddies are generated by a LC eddy shedding event, 

then they may disperse into more rapidly propagating TRWs. 

Statistics 

Figure 1 shows the mean and standard deviation ellipses calculated for 40-HLP current records at 

generally 100-m above the bottom, where the water depth is greater than 1000 m. Records are at 

least one-year long with the western Gulf having ~ 15-month durations. There are some locations 

where the height above the bottom is 500 m; however, these are all in water depths greater than 

2000 m, and because the currents are nearly depth independent in the lower part of the water 

column, the statistics are not significantly affected when compared with the 100 m above the 

bottom level. Means are generally anticlockwise with enhanced flows at the base of the slope ~ 
 

Figure 1. Mean (top) and standard deviation ellipses (bottom) of 40-HLP currents at 100 to 500-m above 

the bottom from recent MMS studies (see text). The mooring locations marked by a color (not 

black) dot are used in Figure 4. 

14 
15 

2000 – 2500 m where the topographic slope is steep. This generally corresponds to the base of 

the Sigsbee Escarpment in the central and western Gulf. In the central Gulf, there is a strong 

mean jet directly above the steepest part of the escarpment slope around 91°W, where maximum 

speeds are ~ 12 cm/s. This is the only location, to date, where an array of bottom-current meter 

moorings was placed across the escarpment (the SEBCEP array, which was industry’s 

contribution to the Exploratory program). Most of the other moorings were above or below the 

escarpment. Nevertheless, it is clear there is an enhanced clockwise flow in the central and 

western parts of the northern Gulf along the escarpment. The means also indicate that flows 

converge towards the escarpment, particularly on the deeper basin side both for the Exploratory 

and Western Gulf studies. The enhanced escarpment mean flows are also observed in the float 

trajectories. Away from the escarpment, the deep floats tend to oscillate around in the same 

general area. If they go close to the escarpment, then they move rapidly to the west. Thus, 

fluctuating TRW flows, which are energetic below the escarpment, have some of their energy 

converted to mean flows by the reflection mechanism of Mizuta and Hogg (2004) through 

topographic rectification by the shoaling topography (DeHaan and Sturges 2005). 

The eddy kinetic energy, represented by the standard deviation ellipses (Figure 1), has a high 

degree of spatial variability. The largest magnitudes are on the west side of the LC, represented 

by “L” and the southeastern part of the exploratory array. Energy decreases from this region in 

all directions, including south. The Eastern Gulf array, “E,” was situated on the northern edge of 

the LC front for most of the deployment interval, yet the energy levels are less than for the 

observations immediately to the west. In the central Gulf below the escarpment, variance 

decreases towards the west, and there is a further small decrease in the western array, where the 

highest energies are in the northwest corner for the moorings deeper than 2000 m. There is a 

sharp reduction in variance above, compared to below the escarpment in both the central and 

western Gulf. Thus in both the western and central Gulf arrays, there are similar patterns with 

energy highest at the upstream (in the sense of TRW propagation with shallower water on the 

right) end with decreasing energy levels in downstream direction and a sharp reduction in energy 

in the shallower water above the steep topographic feature. Otherwise, the ellipses have their 

major axes nearly aligned with the topography, particularly where the slope is steep. This is 

consistent with TRW dynamics. 

Figure 2 shows the tracks of two RAFOS floats below the LC. The LC during this period, was 

extended and in the process of shedding eddy Titanic. The floats are below any direct LC flows. 

Both floats have both cyclonic and anticyclonic loops, and remain in the same general area for 

the six-months of the record, neither migrating to the western basin nor to the west Florida slope 

under the east side of the LC. It could be argued that these types of water parcel displacements 

are characteristic of TRWs, which, to first order, transport momentum but not mass, unlike a true 

eddy with a closed-core circulation. The velocities of the drifters are compared with the nearest 

deep current meter, where the records overlap, and they are quite similar in magnitude with the 

floats having more high frequency content than the velocities from the mooring. This is an 

indication of non-linear nature and spatial in-homogeneity of the wave field. 
Figure 2. Smoothed lagrangian drifter tracks from two Exploratory RAFOS floats at 1500 m. Arrow heads 

at five-day intervals. The black dot is the position of the LSU mooring L07. 

In the exploratory program, 36 RAFOS drifters were deployed at depths greater than 1000 m. 

Most of the drifters had tracks similar in character to Figure 2 in that the oscillations were fairly 

rectilinear with no preferred direction of rotation and the floats remained relatively localized for 

periods of up to six months. Exceptions were if the float ventured near to the escarpment: then 

they were transported westward along the escarpment by the large deep mean flows found there 

(see Figure 1). Of the 36 drifters deployed, only one showed the consistent kinematics of a 

translating eddy. This was near the western Mexican slope, and the drifter made three circuits 

just before it surfaced at the end of the deployment (Figure 3). There appears to be no obvious 

connection with the upper-layer eddy field, though it does approximately precede a westward 

translating upper layer cyclone that in turn precedes a LC anticyclone. 

16 
Figure 3. Smoothed track of RAFOS float RFS0490 at 2000 m for the indicated time interval. Arrow heads 

are at 5-day intervals and dates (mm/dd) are the positions at 0000 GMT. The overlaid satellite 

image (courtesy JHU-APL) of SST is a 3-day composite center around 21 March 2004. 

Spectra 

17 

As an illustration of the decay of EKE from east to west, the KE spectra are shown for four 

moorings (see Figure 1 for locations) that are in the deepest water except for the far western one, 

with the two central ones (L6 and W3) being approximately on the 3500 m isobath. Note the 
Figure 4. Kinetic eddy spectra in variance preserving form for the near-bottom current records across the 

center of the Gulf. The mooring locations are color coded the same as plot lines on Figure 1. 

change of scale between the two plots with the L6 spectra being repeated as a reference. L7 on 

the west side of the LC has the highest energy levels with prominent peaks at 30- and 50-day 

periods. L6 and W3 have similar spectral content but much lower energy levels. However, the 

decrease between L7 and L6 is much greater than between L6 and W3. W2 is at the bottom of 

the steep Mexican slope and has a peak at 12-14 days. The shifting of spectral peaks with 

location was noteworthy for the exploratory currents below the escarpment, with highly 

energetic high frequency motions (~ 10 days) in the northeast section, lower frequency motions 

(~ 60 days) in the southwest part of the array with relatively smooth changes between the two 

along the escarpment. The southeast corner of the array had energetic motions at most of the 

frequencies observed in the rest of the records. It appears that, in the central Gulf, incoming 

TRWs from the east and southeast with a range of frequencies are reflected and refracted by the 

escarpment topography which acts as a kind of filter, trapping the 10-day fluctuations in the 

northeast and allowing the longer period fluctuations to propagate out towards the deeper water 

in the western part of the Gulf. 

Much remains to be explored in developing an understanding of how TRWs propagate through 

the Gulf and where are the preferred generation zones. The connections to LC and surface layer 

eddy variability at various scales have yet to be determined. Developing the correct physics of 

these generation and propagation processes is going to be crucial for nowcast and forecast 

numerical predictions of deep currents in the Gulf. 

18 
References 

DeHaan, C.J., and W. Sturges. 2005. Deep cyclonic circulation in the Gulf of Mexico. J. Phys. 

Oceanogr. 35:1801–1812. 

Hamilton, P. 1990. Deep currents in the Gulf of Mexico. J. Phys. Oceanogr. 20:1087–1104. 

Hamilton, P. 2007.Deep current variability near the Sigsbee Escarpment in the Gulf of Mexico. 

J. Phys. Oceanogr. 37:708–726. 

Hamilton, P.,and A. Lugo-Fernández. 2001. Observations of high-speed deep currents in the 

northern Gulf of Mexico. Geophys. Res. Lett. 28:2867–2870. 

Mizuta, G. and N.G. Hogg. 2004. Structure of the circulation induced by a shoaling topographic 

wave. J. Phys. Oceanogr. 34:1793–1810. 

Oey, L-Y. and H-C. Lee. 2002. Deep eddy energy and topographic Rossby waves in the Gulf of 

Mexico. J. Phys. Oceanogr. 32:3499–3527. 

Welsh, S.E., and M. Inoue. 2000. Loop Current rings and deep circulation in the Gulf of Mexico. 

J. Geophys. Res. 105(C7):16,951–16,959. 

Dr. Peter Hamilton is a Senior Oceanographer with Science Applications International 

Corporation, a position he has held since 1979. He has served as a Principal Investigator on 

many MMS programs in the Gulf of Mexico and other coastal seas. He received his Ph.D. from 

the University of Liverpool (U.K.) in 1973, and followed this with a postdoctoral position at the 

University of Washington. 

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31 
PRESSURE-RECORDING INVERTED ECHO SOUNDER (PIES) 

STUDIES IN THE GULF OF MEXICO 

Kathleen Donohue and D. Randolph Watts, University of Rhode Island 

Introduction 

Three arrays of pressure-recording inverted echo sounders (PIES) and current meter moorings 

were deployed in waters deeper than 1000 m in the Northern Gulf of Mexico to measure and 

coherently map currents and eddies daily through the full water column with mesoscale 

resolution (Figure 5). The Exploratory Array in the north central Gulf was deployed in March 

2003 and recovered April 2004. The Northwest Gulf array was deployed October 2004 to August 

2005, and the Northeast Gulf array in December 2004 to January 2006. Science Applications 

International Corporation (SAIC) led the Exploratory and Northwest Gulf projects while Evans 

Hamilton Inc. led the Northeast Gulf project. Mineral Management Services funded all three 

projects. 

Figure 5. Map of the three MMS-sponsored arrays of pressure-recording inverted echo sounders (PIES, 

blue dots), and current meter moorings (red dots) deployed in the northern Gulf of Mexico. 

Bathymetry contoured every 1000 m depth. 

33 
34 

PIES Methodology 

Within each of the three arrays we produced 4-D maps of temperature, salinity, density, and 

velocity. Round-trip acoustic travel time measured by the inverted echo sounder allowed 

estimates of vertical profiles of temperature, salinity, and density, utilizing empirical look-up 

tables based upon historical hydrography for the region. Estimated horizontal density gradients 

were mapped to estimate baroclinic shear profiles. Pressure fields were leveled via geostrophy 

using mean current measurements. By referencing the baroclinic velocity profiles with deep 

velocities from the mapped pressures and currents, the absolute profiles of geostrophic velocity 

were obtained. Maps were produced with optimal interpolation techniques adapted from 

Bretherton et al. (1976) and outlined in Watts et al. (2001).

Tall moorings provided independent measurements to evaluate our PIES-derived fields of 

temperature and velocity in each experiment. Comparisons between PIES-estimated and directlymeasured mooring temperatures indicate that the empirical relationship holds well in the Gulf of 

Mexico, and demonstrated that the variance explained in the thermocline is approximately 85%. 

A more stringent test of the PIES methodology and mapping is the comparison against measured 

velocities, and the agreement between measured and PIES-estimated series was excellent. The 

rms differences in velocity were less than 10 cm/s near 200 m depth, 6 cm/s near 700 m, and 4 

cm/s at depths below 1500 m. 

Currents and Eddies across the Gulf of Mexico 

The majority of mesoscale eddy variability in the deep-water northern Gulf of Mexico is related 

to the Loop Current, Loop Current Eddies, and frontal eddies. The energy distribution is strongly 

affected by the topography of the deep continental slope, especially the Sigsbee Escarpment 

(Figure 6a). In each of the three arrays, the strongest surface currents and eddies outside the 

Loop Current itself were in Loop Current Eddies. Only the periphery of the Loop Current entered 

these arrays during these observations. In the North Central Gulf two Loop Current Eddies, 

Sargassum and Titanic, entered the eastern portion of the array and passed directly through the 

region to the southwest. The resulting eddy kinetic energy (EKE) was high in the eastern portion 

and diminished to the west. EKE is defined as (1/2) [ (u')2

 + (v')2 ], where u' = (u – U), v' = 

(v – V), (U, V ) = ([u], [v]), and [ ] indicates the average over the observation period. In the 

Northwest Gulf one Loop Current Eddy, Ulysses, entered its eastern portion while other smaller 

and weaker cyclones and anticyclones appeared. The resulting EKE was high in the eastern 

portion and diminished to the west. Loop Current and Loop Current Eddies skirted the southwest 

corner of the Northeast Gulf array, so surface EKE was not as high as the other experiments. 

The strongest deep currents and eddies among these three experiments were found in the North 

Central Gulf array (Figure 6b). Deep eddies entered from the southeast and translated west and 

northwest to impinge upon the Sigsbee Escarpment and track along it. 
Figure 6. Surface and deep eddy kinetic energy determined from the three PIES arrays in the northern 

Gulf of Mexico. Bathymetry is contoured every 1000 m depth. 

a 

b 

The deep currents became concentrated along the steep Sigsbee topography, especially near 90o-

91oW. Most eddies in the deep Gulf remain south of Sigsbee and do not enter into the region to 

its northwest. We note that region is distinct from the shallower-yet continental shelf. In the 

Northwest Gulf the deep eddies were much weaker, but they too were partly steered along the 

topography. Compared within the Northwest Gulf array, the deep eddies were more energetic 

offshore of the 2000 m isobath. Deep eddies entered the Northwest Gulf region from the east and 

did not appear to originate locally. In the Northeast Gulf, five strong deep eddies passed through 

the southern deeper portion of the array. The deep eddies were episodic, associated with intervals 

when upper-layer Loop Current and Loop Current Eddies swept southeast through the array. 

35 
Diagnostic Studies of Vertical Coupling Between Upper and Deep Circulation 

The Central and Northeast Gulf Arrays exhibited several examples of interaction between the 

upper and deep ocean: blocking, joint propagation of upper and lower layers, and baroclinic 

instability. Upper and lower layers are dynamically coupled when their motions stretch or 

squeeze the opposite layer. The lower-layer response to vortex stretching/squeezing tends to 

produce respectively positive/negative relative vorticity to balance the changes in thickness. 

Figure 7 illustrates such a case in the Northeast Gulf Array, in which a deep anticyclone led and 

deep cyclone trailed as the Loop Current or Loop Current Eddy swept southeast through the 

array. This pattern repeated itself five times in 2005. 

Note that the above description of local vertical coupling is highly idealized: we have neglected 

the effects of topography, a spherical earth, and lower-layer advection of a background potential 

vorticity gradient, for example. We refer the reader to Cushman et al. (1990) for a more in-depth 

discussion, and we point out that Welsh and Inoue’s (2000) modeling study reveals the joint 

spin-up of lower layer eddies beneath strong translating upper-ocean features. The lower layer 

potential vorticity (PV) can be diagnosed as follows, where PV = (f + ζ)/H, and f = Coriolis 

frequency (planetary vorticity), ζ = relative vorticity, and H = lower layer thickness from the sea 

floor to the base of the thermocline (6o

C isotherm depth). Figure 8 shows the time series of terms 

contributing to the PV balance at a point where the deep eddies spun up and passed repeatedly. 

The local PV was not constant but varied through a range of about 25%, and this variation, PV 

tendency ∂ PV/∂t, was balanced by PV advection, u (∂ PV/∂x) + v (∂ PV/∂y). 

Figure 7. Case study of a lower-layer cyclone leading an upper-ocean cyclone [30 July – 05 August 2005] as 

the crest of the Loop Current withdraws southeastward in the Northeast Gulf array. Maps of 

surface streamfunction (bold contour lines) superimposed upon shaded contours of pressure at 

1500 m depth for four separate days. In both fields highs are represented by red hues and lows 

represented by blue hues. Bathymetry contoured every 1000 m depth is denoted by the gray 

lines. PIES sites indicated by diamonds; current meters by circles. 

36 
Figure 8. Potential vorticity terms are diagnosed as time series at the location within the Northeast Gulf 

array indicated by the red star. As the cyclone of Figure 7 passed in July-August a local peak PV 

can be seen in the upper panel. The PV tendency is balanced by PV advection, as shown in the 

lower panel. 

In events where deep eddies are vertically coupled to the upper loop current, an array like this 

allows diagnosis of dynamical balances. The time scales, spatial scales and PV balances of deep 

eddies all support that they exhibit the dynamics of topographic Rossby waves (TRWs). 

Future Observational Work 

A current meter option has been added to the PIES, called CPIES, because many PIES 

applications also required deep current measurements. The CPIES includes the Doppler currentsensing head of the Aanderaa RCM-11, buoyed 50 m above the PIES to be out of the bottom 

boundary layer. It now includes acoustic release, a 4+ years deployment capability, and acoustic 

telemetry capability. Two experiments funded by ONR and NSF in the Kuroshio and Kuroshio 

Extension successfully deployed and recovered arrays of CPIES. 

References 

Bretherton, F.P., R.E. Davis, and C.B. Fandry. 1976. A technique for objective analysis and 

design of oceanographic experiments applied to MODE-73. Deep Sea Research 23:559–

582. 

Cushman-Roisin, B., E.P. Chassignet and B. Tang. 1990. Westward motion of mesoscale eddies. 

Journal of Physical Oceanography 20:758–768. 

37 
Welsh, S.E. and M. Inoue. 2000. Loop Current rings and the deep circulation in the Gulf of 

Mexico. Journal of Geophysical Research 105(C7):16951–16959. 

Watts, D.R., X. Qian, and K.L. Tracey. 2001. Mapping abyssal current and pressure fields under 

the meandering Gulf Stream. Journal of Atmospheric and Oceanic Technology 18:1052–

1067. 

Kathleen Donohue received a Ph.D. degree in oceanography from the University of Rhode Island 

in 1995. In 2000, after a post doctoral appointment at the University of Hawaii, she returned to 

the University of Rhode Island where she worked as an assistant Marine Research Scientist from 

2000 to 2006 and presently has an ADVANCE research professor position. Kathleen is a 

physical oceanographer whose research interests include describing the global ocean velocity 

structure with particular focus on western boundary current regimes. 

D. Randolph Watts is a Professor of Oceanography at the University of Rhode Island. His 

current research interests are dynamic and descriptive physical oceanography, with emphasis on 

dynamics and energetics of strong current systems and their large scale eddies. 

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55 
CANEK: 10 YEARS OF OCEANOGRAPHIC OBSERVATIONS IN THE 

CARIBBEAN SEA AND GULF OF MEXICO 

Julio Candela, J. Sheinbaum, J. Ochoa, and A. Badan, CICESE 

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UPPER LAYER SUBSURFACE JETS AND INERTIAL CURRENTS 

IN THE NORTHERN GULF 

Peter Hamilton, Science Applications International Corporation 

Inertial Currents 

Inertial period fluctuations of the currents dominate the high frequency (periods of less than 40 

hours) part of the spectrum in the upper layer of the slope and deep basin. Diurnal and semidiurnal tidal currents are essentially negligible even though diurnal surface tides are evident in 

sea level and the inertial period (= 2π/f, where f is the Coriolis parameter) of ~ 26 hours over the 

northern Gulf slope is close to that of the diurnal tide. Clockwise rotary motions (viewed from 

above) characterize inertial-internal waves. Inertial motions are primarily forced by variable 

surface winds. This includes winter and tropical storms. The inertial wake in deep water, with 

stronger oscillations on the right hand side compared to the left of a hurricane track have been 

extensively studied and modeled (Price 1981; D’Asaro et al. 1995). Inertial currents may also be 

generated by geostrophic adjustment processes and thus may be generated by eddy-eddy and 

eddy-topography interactions. 

The relative vorticity of the background flow affects the frequency of the inertial response such 

that anticyclones and cyclones lower and raise the effective Coriolis parameter, fe. An example 

of this is given in Figure 9 where two adjacent ADCP moorings in the NW Gulf show different 

frequency responses that are shifted by the vorticity of the cyclonic and anticyclonic eddies in 

which they were located for most of the month of May, 2004. Anticyclonic eddies can trap 

inertial oscillations because fe increases with depth and in the cyclonic zones on the outer edges 

of the eddy, and internal-inertial waves cannot propagate with intrinsic frequencies lower than 

the local f. In Figure 9, the kinetic energy increases with depth between 35 and 125 m for 

location U3 in the anticyclone. Kunze (1986) discusses enhanced inertial oscillations just above 

the thermocline in a warm-core ring, and similarly Donohue et al. (2006) show strong subsurface 

inertial currents, with a central frequency ~ 0.9f, within eddy Sargassum, which detached from 

the Loop Current in August 2003. 

In May 2005, an isolated cold front crossed from the NW Texas coast to the SE over the NW 

Gulf moored array (see Figure 9 for locations). Ten out of the 13 moorings had upper-layer 75 

kHz ADCP’s that spanned 40 to 420 m depths. Thus, the response of the upper-layer to relatively 

uniform isolated strong wind impulse could be investigated. The results suggest that there was 

some zonal uniformity of response that was banded meridionally with alternating high and low 

inertial amplitudes with the highest energies on the northern edge of the array. Because the group 

velocity of internal-inertial waves is at a declination to the horizontal and directed towards region 

of lower f, i.e., southwards, the implications are that north-south banded nature of the amplitude 

response could be the result of destructive interference with the horizontally propagating waves. 
Figure 9. RH panels show the kinetic energy spectra, in variance preserving form, for currents at 3 depths 

at U3 and U4 moorings. The spectral peaks are shifted from the local f by the background 

relative vorticity (units fractional f) contoured in the LH panel, which also shows the 30-day 

mean 40-HLP currents at two depths. 

There was no obvious relationship of the spatial variability of the inertial currents to the 

underlying eddies. Similar results were found for a sequence of winter storms for the same array. 

Subsurface Jets 

DiMarco et al. (2004) discuss the possibility that high-speed subsurface currents, with speeds > 

50 cm/s, can occur between 150 and 350 m depth, while surface currents were weak. Drilling 

operators had reported cases of shutdowns caused by such high-speed subsurface flows, which 

have become known as jets. However, the available database was plagued with instrumentation 

problems and results were inconclusive on whether such phenomena could occur in deep water. 

Vertically propagating inertial-internal waves could produce higher speeds at depth than at the 

surface, and DiMarco et al. (2004) cite the case of Hurricane Georges where deep inertial energy 

occurred over the DeSoto slope several days after the passage of the storm. However, the 

available database, after excluding inertial events, suggested that if such jets occur, then they 

seemed to be associated with the edges of anticyclones that were possibly interacting with an 

ADCPs in the upper 400 to 500 m of the water column might have a chance of capturing such a 

adjacent cyclone or frontal eddy. Only moorings that had continuous current profiles from 

subsurface jet. For six such moorings in the central Gulf that give a total of ~ seven years of 

80 
81 

Figure 10. Unfiltered speed from the 450 m ADCP at T5 for the indicated interval. 

measurements, no significant jet-like events were found. However, in the NW Gulf upper-layer 

ADCP records, a number of subsurface jets that fit the criteria of maximum speeds > 50 cm/s 

occurring between 150 and 350 m depth with lesser speeds near the surface, have been found. Of 

the 17 subsurface jet events identified in the 450-m ADCP records, 10 are considered to be 

primarily inertial events, and seven are non-inertial. Other than having more 450-m ADCP years 

(14) in the western Gulf than in the central Gulf, it is not yet clear why the NW part of the slope 

as more subsurface jet events than the central or eastern parts of the slope. 

cm/s). The time series of upper-layer temperatures for this event show the coldest water arriving 

h

Figure 10 shows the current speeds in the upper 450 m of the water column at mooring T5 in the 

NW Gulf (see Figure 11 for location). This clearly fits the criteria for a subsurface jet with 

speeds exceeding 70 cm/s around 150 m depth, with much lower speeds at the surface (~ 40 
82 

Figure 11. 

are plotted as 3D pseudo profiles. The location of the T5 mooring is 

noted by the gray arrow. 

1-day mean 3-HLP temperature at 150 m and currents at selected depths for 26 February 2005, 

0000 GMT. The currents 

at 250 m, one to two days before it arrives at 75m, which implies reversing horizontal thermal 

wind gradients above and below the jet. This indicates that this event is primarily geostrophic. 

Maps of the horizontal temperature and velocities (Figure 11) show that T5 was located in a cold 

cyclone, which was interacting with a larger warm anticyclone to its south. The interaction 

causes the vertical center axis of rotation of the cyclone to be tilted towards the anticyclone, and 

it is this distortion of the density field that causes diverging isotherms that support a geostrophic 

subsurface jet. A number of other similar cases that also involve cylone-anticyclone interactions 

cur in this NW study. 

 

D’Asar

torm. Part I: Data and comparisons with 

oc

References 

o, E.A., C.C. Eriksen, M.D. Levine, P. Niiler, C.A. Paulson, and P. van Meurs. 1995. 

Upper-ocean inertial currents forced by a strong s

linear theory. J. Phys. Oceanogr. 25:2909–2936. 
83 

DiMarc

egion of the Gulf of Mexico. U.S. Dept. of the Interior, 

Dononh

Volume II: 

nogr. 16: 

rice, J.F. 1981. Upper ocean response to a hurricane. J. Phys. Oceanogr. 11:153–175. 

e Gulf of Mexico and other coastal seas. He received his Ph.D. from 

e University of Liverpool (U.K.) in 1973, and followed this with a postdoctoral position at the 

niversity of Washington. 

Slide 1 

o, S. F., M. K. Howard, W. D. Nowlin, Jr., and R. O. Reid. 2004. Subsurface, high-speed 

current jets in the deepwater r

Minerals Management Service, Gulf of Mexico OCS Region, New Orleans, LA. OCS 

Study MMS 2004-022. 98 pp. 

ue, K.D., P. Hamilton, K. Leaman, R.R. Leben, M. Prater, D.R. Watts, and E. Waddell. 

2006. Exploratory study of deepwater currents in the Gulf of Mexico. 

Technical Report. U.S. Dept. of the Interior, Minerals Management Service, Gulf of 

Mexico OCS Region, New Orleans, LA. OCS Study MMS 2006-074. 430pp. 

Kunze, E. 1986. Near-inertial wave propagation in a warm-core ring. J. Phys. Ocea

1444–1461. 

P

Dr. Peter Hamilton is a Senior Oceanographer with Science Applications International 

Corporation, a position he has held since 1979. He has served as a Principal Investigator on 

many MMS programs in th

th

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INTRA-AMERICAS SEA OCEAN NOWCAST/FORECAST SYSTEM (IASNFS): 

AN OPERATIONAL REAL-TIME NOWCAST/FORECAST SYSTEM FOR 

INTRA-AMERICAS SEA 

Dong S. Ko, Naval Research Laboratory 

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NEW MEASUREMENT TECHNOLOGIES AND DATA ANALYSIS TECHNIQUES 

John Toole, Woods Hole Oceanographic Institution 

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131 

BREAKOUT SESSION SUMMARIES 

The purpose of the USA-Mexico Workshop on the Deepwater Physical Oceanography of the 

Gulf of Mexico was (1) to determine future observational plans and needs for modeling 

information in USA and Mexican waters, (2) to determine future modeling plans and needs for 

observational information in USA and Mexican waters, and (3) to initiate intensive USA 

coordination with Mexico in planning and implementing future physical oceanographic modeling 

and data acquisition in the Gulf of Mexico. Breakout sessions were conducted to fulfill these 

purposes. 

OBSERVATIONAL PLANS AND NEEDS FOR MODELING INFORMATION 

IN USA AND MEXICAN WATERS (S-1 & S-3) 

Co-Chairs: Dr. Steven DiMarco, TAMU 

 Dr. Antonio Badan, CICESE 

Rapporteur: Dr. Walter Johnson, MMS 

Leading Gulf of Mexico processes of concern include the Loop Current (LC) position, transport, 

and stability; Loop Current Eddy (LCE; anticyclone) shedding and translation; Loop Current 

frontal eddy (LCFE; cyclone) dynamics; LCFE generation at (and downstream translation from) 

Campeche Bank; deep water general (mean) and transient (e.g., Topographic Rossby Waves 

(TRWs) and deep eddies) circulation; and dynamic mechanisms coupling the deep and shallow 

Gulf currents. While satellite radar altimetry and thermal and color imagery can serve to 

delineate shallow Gulf general circulation and eddy features, they are ineffective for this purpose 

in the lower layer of the deep Gulf. There is special interest in the response of the Gulf to 

extreme wind events; e.g., air-sea interaction in the upper 200 m, near-surface (upper 10 m) 

processes (e.g., near-inertial motions, frontal convergences, momentum transfers, heat content 

and fluxes, and mixing), and open ocean upwelling and turbulent entrainment. Reflecting the 

predominance of steep continental slopes (escarpments) in the Gulf, there is also a special 

interest in escarpment dynamics, including LC-topography interactions, generation of bedforms 

and furrow currents, and shelf/slope vertical exchanges of nutrients, biomass, heat, particles, etc. 

that couple biogeochemical and circulation processes through, for example, wintertime cascading 

of shelf waters at the shelfbreak of the Northern Gulf. With a sill depth of 1,900 m and the 

deepest depth reported in the range of 3,750 to 4,380 m, the flushing time and flushing processes 

of the deep water are open questions. For example, deep ventilation of the water column must 

play a role on time scales of a year and longer, but little is known about it. 

Improvements in transport estimates are needed. A fully consistent set of simultaneous estimates 

of volume transport through the Yucatan Channel and Straits of Florida (Key West to Havana, 

Old Bahamas Channel, Northeast Providence Channel, and West Palm Beach to Settlement 

Point, Bahamas) does not exist. Considering the nature of the variability, several-year time series 

of de-tided daily values and a careful design of the sampling grid are needed. In particular, 

CICESE colleagues may be able to help access Cuban waters, which would greatly facilitate 

these transport balance studies. 
132 

Influences on the LC and LCE shedding process from perturbations in the Cayman Basin 

circulation, or further upstream in the IAS, are of interest. 

The impact of strong storms on the open Gulf, including the LC and LCEs, as well as coastal 

waters, is of great scientific interest and practical consequence to the offshore industry in 

planning evacuations from its moored platforms. This topic requires attention to the upper ocean 

heat content and wave field, as well as surface winds and currents and their variation in space 

and time. The generation and vertical and horizontal propagation of near-inertial motions in the 

presence of the LC and warm and cool core eddies and their interactions are significant. Storm 

intensification over warm core eddies can be important. These transient, submesoscale processes 

present space-time resolution challenges for both observationalists and modelers. These 

challenges can only be met by a comprehensive approach, including air-deployable sensing 

systems, airborne remote sensing, moored and drifiting buoys with ADCPs, thermistor strings, 

etc. NOAA (NWS & OAR), Navy, environmental companies, and academia have much of the 

required infrastructure; however, better coordination among these groups is needed. 

A good example of improved coordination is the spatial array of real-time reporting ADCPs 

attached to dozens of oil rigs in the Northern Gulf fostered by MMS, with the data management 

provided by NDBC and cooperation from the offshore industry. 

Another example is the present effort to coordinate MMS and PEMEX observational programs 

across the deep Gulf, including moored current meter and PICES arrays and hydrographic (CTD) 

transects. There is also hope for collaboration between American and Mexican circulation 

modelers. And there is hope that the Gulf of Mexico Coastal Ocean Observing System Regional 

Association (GCOOS-RA) and the Southeast Coastal Ocean Observing Regional Association 

(SECOORA), both regional coastal ocean components of the USA’s Integrated Ocean Observing 

System (IOOS), will become coordinated and work with Mexican and other adjacent entities in 

the Caribbean Sea. 

PEMEX is conducting studies of Campeche Sound where surface drifters have found cyclones 

with current speeds of 100 cm/s and other currents up to 100 to 150 cm/s. PEMEX is also 

conducting studies of Campeche Bank where an ultra-deep cyclone has been found propagating 

to the west. PEMEX is pursuing exploratory studies on the Western Gulf Shelf with a large 

number of moorings and needs to coordinate with USA, including for acoustic sources used for 

tracking floats in deep water. The long-term moorings need to be maintained for 5 to 10 years for 

stable statistics. Mobile moorings are used for exploratory purposes. USA-Mexican collaboration 

could include coordination of hydrographic transects and moorings. 

An LSU group (viz., Inoue, Welsh, and Rouse) is maintaining a long-term current meter mooring 

under the LC. Their results will help design and interpret future studies in the Northern Gulf. 

Coastal HF radars have proven to be useful for estimating synoptic maps of surface currents in 

the coastal ocean, especially within the IOOS program. There is potential for extending their use 
133 

to offshore platforms, which would require cooperation with the offshore industry and various 

agencies. 

There is no other observational subsystem more important for estimating the space-time evolving 

quasi-geostrophic circulation of the LC, LCE, etc. than the satellite radar altimeters. Hence, 

support of the satellite altimeter constellation should be shown by the ocean community at every 

opportunity. 

The Gulf of Mexico modeling strategy should include utilization of an (atmospheric) mesoscale 

meteorological model, wind-current interactions in momentum flux estimates, and independent 

observations for heat and moisture fluxes to validate and verify model estimates of these fluxes. 

Physical-biological interactions of significance in the Gulf of Mexico include open ocean and 

coastal upwelling, the impact of near-bottom currents on benthic communities, and the affinity of 

whales for cyclonic eddies in the Western Gulf. 

Highest priority was given to process studies of (1) eddies and fronts, (2) lower layer circulation, 

(3) Loop Current, (4) upper layer circulation (including air–sea exchanges and responses to 

severe weather events), and (5) biogeochemical coupling. 

A model-based re-analysis using the observations from 2001 to 2005 would be valuable for 

diagnostic studies. 

The MMS NTL (Notice to Lessees) No. 2009-G02 regarding the Ocean Current Monitoring 

dataset has potential for further enhancement of sensor suites; e.g., adding air-sea sensors. 

However, there are stewardship issues to be resolved. 

From a numerical modeling perspective, data from the NDBC, TABS, and COMPS buoys are 

valuable for forcing, verification and validation, and/or data assimilation. However, there is 

concern for adequate resources to support the manpower needed for analysis. 

There is a need for a specific Loop Current study with the following components: 

 • moored sensor array deployed for mapping purposes 

 • deep Lagrangian floats 

 • gliders with CTDs (profiling from the surface to 1 km deep, and deployed for 

 up to six months), including in the Mexican waters of the Southwestern Gulf 

 • AXCTDs (air-deployed CTDs) 

 • AXCPs (air-deployed electromagnetic profilers for measuring currents) 

 • surface drifters, especially for the data void in Mexican waters off the western 

 Yucatan Peninsula 

Satellite remote sensing (esp. radar altimetric SSH and SST) is a viable observing system 

component. Air-deployed sensing systems are invaluable for adaptive sampling of the LC, LCEs, 
134 

and LCFEs. Coastal HF radars can be useful for making synoptic surface current maps for the 

deep Gulf, especially in the Northern Gulf with its relatively narrow shelf. 

For the MMS transect study, the survey lines should extend across the Gulf with three parallel 

meridional lines between 88 and 91 W. The lines should be, as much as possible, perpendicular 

to the bottom topography. And their selection and design should be based upon the space-timeamplitude scales of the prevailing processes. The transects should be sampled with gliders and 

PIES. The mean and variable flow through the transects would be observed. However, the 

observations would not be sufficiently coherent for mapping TRWs and eddies. Yet, they could 

provide information about Mississippi Canyon of use to whale and other ecological studies. It is 

curious that NOAA’s global GOOS surface drifter and ARGO profiing float observing systems 

aim to estimate meridional transports, yet they are missing from the Gulf. 

For long-term monitoring, MMS could consider the NSF OOI concept of “Endurance” (i.e., 

fixed positions) and “Pioneer” (i.e., movable positions) arrays. MMS should also consider CPIES 

long-term stations along altimeter paths, which would constitute a sparse array. PIES arrays in 

the Yucatan Strait and the Straits of Florida might facilitate a transport sensitivity study. 

MODELING PLANS AND NEEDS FOR OBSERVATIONAL INFORMATION IN USA 

AND MEXICAN WATERS (S-2 & S-4) 

Co-Chairs: Dr. Robert Weisberg, USF 

 Dr. Julio Sheinbaum, CICESE 

Rapporteur: Dr. Carole Current, MMS

Fundamental Questions 

The first task was to identify the physical oceanographic questions that should be addressed to 

meet the implicit objectives of breakout sessions S-2 and S-4. These objectives were to formulate 

modeling plans and address and prioritize needs for observational information in USA and 

Mexican waters. 

Although many possible questions were considered, the most necessary questions were 

determined by identifying and prioritizing crucial information gaps in Gulf of Mexico physical 

oceanography. 

Three major physical oceanographic questions (Table 1) that remain substantially unanswered in 

the Gulf of Mexico were identified. 
135 

Table 1. Major Scientific Questions 

 • What controls the Loop Current evolution and eddy shedding processes in the Gulf of 

 Mexico? 

 • What are the energy cascades from the Loop Current and its eddies to other motions: TRWs, 

 vortices, subsurface jets, and other ocean processes, including the fluxes of energy through 

 and the dissipation of energy within the Gulf of Mexico? 

 • Is there a deep, coherent mean ocean circulation in the Gulf of Mexico? 

Processes that control the growth and penetration of the Loop Current in the Gulf of Mexico, as 

well as those governing eddy shedding frequency and location, remain uncertain at present. The 

Loop Current and associated Loop Current Eddies are a source of tremendous energy within the 

Gulf of Mexico, and the processes such as Topographic Rossby Waves (TRWs), vortices, 

subsurface jets, and other ocean processes by which this energy moves through the Gulf and 

eventually dissipates need further investigation. Evidence indicates that a deep mean cyclonic (or 

anticlockwise) flow exists at 2,000 m depth around the perimeter of the Gulf (Sturges et al. 

2004). 

However, the mean flow is not known throughout the deep Gulf of Mexico at most depths. 

Future Gulf deep ocean observations should determine whether or not a deep, coherent mean 

ocean circulation exists. 

The modeling program formulated to deal with the questions of Table 1 is discussed in the next 

section, Modeling Program. Observations needed in support of this modeling program are 

discussed in the final section, Observations in Support of Models. 

Modeling Program 

Modeling plans for USA and Mexican waters that are designed to answer the questions presented 

in Table 1 were discussed and formulated. Elements of the modeling program that emerged are 

listed in Table 2 and described and discussed in this section. 

A modeling program that is conjoined with a data acquisition effort in a unified modeling and 

observational program can be established and operated using the best available observational 

database relative to a given period of time. Modeling and observational studies should be 

done simultaneously and cooperatively to improve modeling results. Although conjoined 

modeling and data acquisition efforts are recommended, it is with full knowledge that this 

interaction is not always easy. 
136 

Table 2. Attributes of Modeling Program 

 • The modeling program should be conjoined with the observational program. 

 • The modeling component should encourage the exercise of several different model 

 frameworks (models and data assimilation schemes) and modeling groups. 

 • Models all require diagnostic analysis to define the kinematics, dynamics, and energetics of 

 the eddy shedding processes and the energy dissipation within the Gulf of Mexico; i.e., how 

 do the models themselves work and what do they tell us? 

 • Model-observation and model-model comparisons should be performed, including the 

 development of appropriate metrics on which to base these comparisons. 

 • Model-observation comparisons should include process diagnoses as model validations. 

About 20 different numerical models are presently available that have been adapted for 

simulation of circulation within the Gulf of Mexico, although simulations by some, such as the 

Princeton Ocean Model (POM) (and its derivatives) and the Hybrid Community Ocean Model 

(HYCOM), often may be more useful than simulations by others. Some models are better 

adapted to certain applications than others; for example, operational models tend to be relatively 

simple, robust, and efficient, but may not give the best results for research purposes. 

A unified circulation model of the Gulf may be developed in the long-term future, but it may be 

better at present to encourage three to five of the 20 models. Much is learned from differences 

between models, though the modelers probably differ more in their approaches than the models 

per se. Hurricane prediction depends on an ensemble of models but at the present stage of 

development, a solidly funded modeling base must precede any later consideration of ensemble 

modeling. 

Models should focus on triggers of high energy events such as eddy spawning and LC intrusions. 

Objectives of Gulf of Mexico process modeling should include description of the kinematics and 

energetics of eddy shedding, as well as relevant dynamical balances. Eddy shedding processes 

are very relevant to the MMS mission for several reasons, including the effects of LCEs on oil 

and gas production in the Gulf. 

The Gulf circulation may often behave as a two-layer system, and this concept can be helpful for 

purposes of modeling and data analyses. Modelers should examine the processes that link upper 

and lower layers of Gulf of Mexico ocean circulation. The interaction of these layers and energy 

flow between upper and lower layers is of particular interest in deep waters. Frictional 

dissipation of energy at the seafloor and other interactions of the deep layer with bottom 

topography are relevant as well. 
137 

Prediction of eddy shedding can be a challenging goal for numerical modelers. However, 

difficulties in determining phasing of instabilities could be addressed with assimilation of 

additional observational data. 

Selection of model resolution is not a simple issue and should be carefully weighed. For some 

problems, models of eddy-resolving mesoscale resolution are preferable, and, for other problems, 

Topographic Rossby Wave (TRW) -resolving models, as an example, are used. Model resolution 

can be selected with the objective of pinpointing the correct physical processes, or it might be 

selected with the objective of enhancing predictability. 

Physical oceanographic modeling is often dependent on the extent of observational data available 

in the regions to be modeled. Boundary conditions, initial conditions, forcing functions, and data 

assimilation all benefit from access to and usage of the best possible meteorological and physical 

oceanographic data available within and around the model domain. Wind speed and direction, 

river outflow, surface and subsurface temperature and salinity fields, satellite altimetric Sea 

Surface Height (SSH) and other satellite observations, surface and subsurface current speed and 

direction from Lagrangian drifters or Eulerian moored data, ocean current transport estimates, 

and wave field data can all be helpful in setting up and operating a skillful simulation of surface 

and subsurface ocean currents and circulation processes in the Gulf of Mexico. 

A single model ensemble or multi-model ensemble approach is recommended, possibly by the 

four groups that are running adjoint models in the Gulf. Errors for prediction must be addressed, 

as well as uncertainties for interpreting observations. 

Particular attention of modelers to thorough sensitivity testing is needed during this modeling 

program. Sensitivity testing is too often neglected or minimized, especially in data assimilation 

applications. 

Model–observation comparisons should be performed for purposes of model validation and 

verification and model intercomparisons. Model output should be compared with site specific 

deep mooring data. The statistics ought to compare well. For example, modeled currents are 

often too weak when compared with field observations, a deficiency which needs to be 

established and dealt with in each model implementation. Large datasets that will soon be 

available from three recent MMS studies need to be utilized further in detailed model/data 

comparisons. These studies are The Exploratory Study of Deepwater Currents in the Gulf of 

Mexico (Donahue et al. 2006), the Survey of Deepwater Currents in the Northwestern Gulf of 

Mexico (Donahue et al. 2008), and the Survey of Deepwater Currents in the Eastern Gulf of 

Mexico (field work is completed and draft report is in preparation). 

Metrics of comparison for modelers should guide establishment of initial conditions, boundary 

conditions, forcing requirements, and error estimates which will include model error estimates, 

observational error estimates, boundary conditions and errors, surface forcing and uncertainty 

estimation, and background or “first guess” estimation. The metrics needed by modelers are 

further discussed below. 
138 

Observations in Support of Models 

Observational data from USA and Mexican waters that must be acquired in support of the 

modeling program described in Table 2 were discussed (Table 3). 

Table 3. Attributes of Observations Needed in Support of Models 

 • Rely on the PEMEX and CICESE arrays to obtain a large-scale, basin-wide set of moored 

 observations. 

 • Concentrate the USA full water column fixed array on the LCE shedding region. 

 • Plan for the use of gliders, floats, drifters, expendable profilers, etc. in addition to the usual 

 MMS instrumentation suite to maximize 3-D, subsurface data acquisition over a variety of 

 scales. 

 • Plan an adaptive sampling program to observe cyclonic/anticyclonic vortex evolution and 

 interactions. 

 • Consider conducting a deep Lagrangian observational and modeling experiment. 

 • Archive data at the regional data center at TAMU as well as at NODC. 

 • Encourage agency support for improved atmospheric forcing fields through IAS meso-scale 

 modeling. 

 • Encourage Mexican support for HF-radar coverage across the Yucatan Strait. 

 • Encourage Mexican support for the redeployent of a Yucatan Strait array. 

 • Ensure observations are fully 3-D because subsurface data are necessary for modeling. 

Surface data are relatively easily available to modelers, but modelers also need data from 

throughout the water column. Subsurface data are crucial for adjoint data assimilation efforts. 

The Navy needs subsurface real-time data (ideally, full water column currents) for their 

predictive modeling. Instrumentation used in the field observation program should include floats 

and gliders, as well as Inverted Echo Sounders with Pressure (PIES), and current meter 

moorings. Data throughout the upper 60 m of the water column are especially needed to model 

the upper ocean response to hurricanes, cold front passages, and other storms. Technologies 

suggested for acquiring these storm data include moorings designed to withstand storm 

conditions, surface drifters, Profiling Autonomous Lagrangian Circulation Explorer (PALACE) 

floats, expendable current and CTD profilers (e.g., EM-APEX), and High Frequency (HF) radar. 

For example, HF radar-derived surface currents could be acquired from the Yucatan Peninsula 

by the Mexicans. 

What fraction of Loop Current energy is transferred into TRWs? Overall, the amount of energy 

may be relatively small. This information will indicate how much of the study should be 

involved with TRWs. 
139 

Satellite datasets are currently used to guide adaptive data acquisition schemes. However, use of 

additional field observations as well as modeling can be helpful in this regard. An adaptive data 

acquisition/modeling program using gliders and air-deployable, expendable profilers could 

resolve features such as cyclones (LCFEs) that form along the frontal edges of the LC. These 

new technologies should be tried. 

The Gulf of Mexico is a large domain for modelers, and obtaining sufficient data within this 

entire domain is not easy. The LC is historically under-sampled, and more field observations in 

the LC region are recommended. Measurements of deep cyclones of diameter <100 km are 

needed to improve modeling of their origins, movements, and dynamics. Field observations of 

shelf and deep circulation interactions would be useful to modelers. In addition, further field 

observations covering the deep outflow of the Gulf would be useful. Scarcity of historical data in 

the Southern Gulf is a problem that should be addressed in upcoming observational programs. 

Possibly MMS could sponsor a Southwestern Gulf of Mexico data acquisition program, in 

cooperation with PEMEX. 

Modelers and modeling should play a role in planning data acquisition campaigns. Initialization 

is crucial for process modeling in the deep ocean, and this should be considered in determining 

the LC array locations. The array recommended by MMS (Figure 12C), if shifted slightly in 

location, could reveal more about upstream conditions. The array recommended by SAIC (Figure 

12A), if more spread out, would allow models to more easily assimilate data indicating the 

position of the LC. However, modelers also would like a greater concentration of field 

observations in the two LC areas where deep cyclones are thought to originate. The present 

location of Mexican moorings (Figure 12B) and future Mexican plans for these moorings should 

be considered in the array design. 
140 

A. B.

C. 

Figure 12. Observational array configurations discussed. A) Hamilton/SAIC suggested array configuration 

including over two dozen PIES as well as moorings. B) Some of the currently operational (red) 

and historical (green) locations of Mexican moorings. C) Lugo-Fernández/MMS suggested 

mooring array configuration. 
141 

References 

Donohue, K., P. Hamilton, K. Leaman, R. Leben, M. Prater, D. R. Watts, and E. Waddell. 2006. 

Exploratory study of deepwater currents in the Gulf of Mexico. U.S. Dept. of the Interior, 

Minerals Management Service, Gulf of Mexico OCS Region, New Orleans, LA. OCS 

Studies MMS 2006-073 (Volume 1) and MMS 2006-074 (Volume II), 430 pp. 

Donohue, K., P. Hamilton, R. Leben, R. Watts, and E. Waddell. 2008. Survey of deepwater 

currents in the northwestern Gulf of Mexico. Volume I: Executive summary. U.S. Dept. 

of the Interior, Minerals Management Service, Gulf of Mexico OCS Region, New 

Orleans, LA. OCS Study MMS 2008-030. 73 pp. 

Sturges, W., E. Chassignet, and T. Ezer. 2004. Strong Mid-Depth Currents and a Deep Cyclonic 

Gyre in the Gulf of Mexico: Final Report. U.S. Dept. of the Interior, Minerals 

Management Service, Gulf of Mexico OCS Region, New Orleans, LA. OCS Study MMS 

2004-040. 89 pp. 
143 

RECOMMENDATIONS 

In addition to numerous recommendations embedded throughout this report, five salient, overarching recommendations are articulated below: 

• Progress towards fulfilling the long-term goal of establishing a synoptic 

analysis and retrospective re-analysis system for the Gulf of Mexico depends 

upon conducting rigorous skill assessments of numerical models on a 

continuing basis as the modeling subsystems and observing subsystems 

advance. 

• Hence, a suite of phenomenological as well as statistical and operational 

metrics needs to be developed against which progress can be measured (see 

Appendices I & II for a start). 

• To complement the satellite radar altimeters, the real-time observing 

subsystem needs to include (1) long-term moorings/stations; (2) CTD, etc. 

profiling floats and gliders; (3) deep floats; (4) surface drifters; and 

(5) offshore bottom pressure gauges to complement coastal tide gauges. 

• Substantial and enduring progress will depend upon collaboration between 

USA and Mexico, observationalists and modelers, researchers and operational 

oceanography personnel, oceanographers and ecologists, and industry and 

agencies. In particular, in the USA, in addition to MMS leadership, 

engagement by the Navy, NOAA, NASA, NSF, and possibly EPA and 

USACOE is essential. 

• Provision needs to be made for periodic scientific communication between 

American and Mexican cohorts concerned with the observing and modeling 

subsystems of the Gulf of Mexico. 
145 

APPENDIX I: IMPORTANT METRICS FOR GULF OF MEXICO 

MODEL SKILL ASSESSMENTS 

General Considerations 

• Include both free-running simulations and data assimilative runs. 

• Include subsurface metrics, as well as metrics for surface fields. 

• Conduct sensitivity studies for every adjustable parameter, including open 

boundary conditions, surface forcing, horizontal and vertical resolution, and 

turbulence closures. 

• Conduct process validations as the first priority and gridded-field verifications 

as the second priority. 

Major Processes to Be Validated 

• LCE (i.e., large anticyclones/rings) statistics; e.g., pdf for eddy shedding 

intervals, eddy paths, eddy translational velocities, eddy sizes and strengths, 

and eddy decay rates and zones 

• Similar statistics for upper ocean and deep ocean mesoscale cyclones and 

anticyclones 

• General energy levels, spectra, and energy fluxes 

• Near-inertial motions and their generation, propagation, dispersion, and 

dissipation 

• Tidal energy on shelves versus deepwater 

• TRW generation, propagation, dispersion, and dissipation 

• Transports through Yucatan Channel and Straits of Florida, including 

backflows, tidal fluxes, barotropic and baroclinic components, heat and salt 

fluxes, water mass fluxes 

• Lagrangian as well as Eulerian transports 

• Vertical and horizontal structure of the LC 

• Benthic mean and variable general circulation patterns 
147 

APPENDIX II: KEY OBSERVATIONAL DATA SETS AVAILABLE 

FOR MODEL SKILL ASSESSMENTS 

1 – Current Meter Data under the Loop Current: 

Inoue, M., S.E. Welsh, L.J. Rouse, Jr., and E. Weeks. 2008. Deepwater currents in the Eastern 

Gulf of Mexico: Observations at 25.5°N and 87°W. U.S. Dept. of the Interior, Minerals 

Management Service, Gulf of Mexico OCS Region, New Orleans, LA. OCS Study MMS 

2008-001. 95 pp. 

2 – Loop Eddy and Loop Current Altimetry Analyses: 

Donohue, K., P. Hamilton, K. Leaman, R. Leben, M. Prater, D.R.Watts, and E. Waddell. 2006. 

Exploratory study of deepwater currents in the Gulf of Mexico. Volume II: Technical 

report. U.S. Dept. of the Interior, Minerals Management Service, Gulf of Mexico OCS 

Region, New Orleans, LA. OCS Study MMS 2006-074. 430 pp. 

McKone, K., N. D. Walker, and E. Weeks. 2007. Full-water column currents near the Sigsbee 

Escarpment (91-92oW. Longitude) and relationships with the Loop Current and 

associated warm and cold-core eddies, U.S. Dept. of the Interior, Minerals Management 

Service, Gulf of Mexico OCS Region, New Orleans, LA. OCS Study MMS 2007-056. 

107 pp. 

3 – Spatial Arrays of Current Meter Data: 

Donohue, K., P. Hamilton, K. Leaman, R. Leben, M. Prater, D.R.Watts, and E. Waddell. 2006. 

Exploratory study of deepwater currents in the Gulf of Mexico. Volume II: Technical 

report. U.S. Dept. of the Interior, Minerals Management Service, Gulf of Mexico OCS 

Region, New Orleans, LA. OCS Study MMS 2006-074. 430 pp. 

Donohue, K., P. Hamilton, R. Leben, R.Watts, and E. Waddell. 2008. Survey of deepwater 

currents in the northwestern Gulf of Mexico. Volume II: Technical report. U.S. Dept. of 

the Interior, Minerals Management Service, Gulf of Mexico OCS Region, New Orleans, 

LA. OCS Study MMS 2008-031. 375 pp. 

Hamilton, P., J.J. Singer, E. Waddell, and K. Donohue. 2003. Deepwater Observations in the 

Northern Gulf of Mexico from In-Situ Current Meters and PIES. Final Report. Volume 

II: Technical Report. U.S. Dept. of the Interior, Minerals Management Service, Gulf of 

Mexico OCS Region, New Orleans, LA. OCS Study MMS 2003-049. 95 pp. 

McKone, K., N. D. Walker, and E. Weeks. 2007. Full-water column currents near the Sigsbee 

Escarpment (91–92oW. Longitude) and relationships with the Loop Current and 

associated warm and cold-core eddies, U.S. Dept. of the Interior, Minerals Management 
148 

Service, Gulf of Mexico OCS Region, New Orleans, LA. OCS Study MMS 2007-056. 

107 pp. 

Sheinbaum J., A. Badan, J. Ochoa, J. Candela, D. Rivas, and J.I. González. 2007. Full water 

column current observations in the central Gulf of Mexico. U.S. Dept. of the Interior, 

Minerals Management Service, Gulf of Mexico OCS Region, New Orleans, LA. OCS 

Study MMS 2007-022. xiv + 58 pp. 

4 – Platform Data: 

NDBC Web Site: http://www.ndbc.noaa.gov/maps/ADCP_WestGulf.shtml 

5 – Lagrangain Trajectories: 

Donohue, K., P. Hamilton, K. Leaman, R. Leben, M. Prater, D.R.Watts, and E. Waddell. 2006. 

Exploratory study of deepwater currents in the Gulf of Mexico. Volume II: Technical 

report. U.S. Dept. of the Interior, Minerals Management Service, Gulf of Mexico OCS 

Region, New Orleans, LA. OCS Study MMS 2006-074. 430 pp. 

6 – Historical Data Analyses: 

Nowlin, W. D., Jr., A. E. Jochens, S. F. DiMarco, R. O. Reid, and M. K. Howard. 2001. 

Deepwater Physical Oceanography Reanalysis and Synthesis of Historical Data: 

Synthesis Report. OCS Study MMS 2001-064, U.S. Dept. of the Interior, Minerals 

Management Service, Gulf of Mexico OCS Region, New Orleans, LA. 528 pp. 

Further relevant reports can be found at: 

http://www.gomr.mms.gov/homepg/regulate/environ/techsumm/rec_pubs.html

In particular, for eddy statistics, see Bob Leben’s altimetric SSHA movie, Peter Hamilton’s 

current meter and PIES data, Nan Walker’s GOES imagery, and Bob Leben’s altimeter data. 
149 

ACRONYMS 

ADCP Acoustic Doppler Current Profiler 

ARGO Global array of several thousand profiling floats 

AXCP Air Deployable Expendable Current Profiler 

AXCTD Air Deployable Expendable Temperature and Salinity Profiler 

CICESE Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, BC 

COMPS Coastal Ocean Monitoring and Prediction System 

CONACyT Mexican National Council for Science and Technology 

CPIES PIES with a current meter 

CTD Temperature and Salinity Profiler 

CU University of Colorado 

EM–APEX Electromagnetic–Autonomous Profiling Explorer, an air-deployable, expendable

velocity profiler 

GCOOS-RA Gulf of Mexico Coastal Ocean Observing System Regional Association 

GOOS Global Ocean Observing System 

Gulf Gulf of Mexico 

HF high frequency 

HYCOM Hybrid Community Ocean Model 

IAS Intra-Americas Sea (viz., the combined Gulf of Mexico, Caribbean Sea, Straits 

of Florida, and adjacent Atlantic waters west of 55W) 

IASNFS Intra-Americas Sea Ocean Nowcast/Forecast System 

IES Inverted Echo Sounder 

IOOS USA Integrated Ocean Observing System 

LC Loop Current 

LCE Loop Current Eddy (i.e., large, deep anticyclonic “ring”) 

LCFE Loop Current Frontal Eddy (i.e., small, shallow cyclonic eddy) 

LSU Louisiana State University 

MMS Minerals Management Service 

NDBC National Data Buoy Center/NWS 
150 

NESDIS National Environmental Satellite Data and Information Service/NOAA 

NOAA National Oceanic and Atmospheric Administration 

NODC National Oceanographic Data Center/NESDIS 

NRL Naval Research Laboratory 

NRL ONFS Naval Research Laboratory Ocean Nowcast/Forecast System 

NSF National Science Foundation 

NWS National Weather Service/NOAA 

OAR Office of Oceanic and Atmospheric Research/NOAA 

OOI Ocean Observing Initiative/NSF 

PALACE Profiling Autonomous Lagrangian Circulation Explorer float 

PEMEX Petroleos Mexicanos (Mexico’s state-owned petroleum company) 

PIES IES with bottom pressure sensor 

POM Princeton Ocean Model 

PU Princeton University 

RAFOS SOFAR spelt backwards; acoustically tracked subsurface floats 

RSMAS Rosenstiel School of Marine and Atmospheric Science, University of Miami 

SAIC Science Applications International Company 

SECOORA Southeast Coastal Ocean Observing Regional Association 

SSH Sea surface height 

SST Sea surface temperature 

TABS Texas Autonomous Buoy System 

TAMU Texas A&M University 

TRW Topographic Rossby Wave 

URI University of Rhode Island 

USF University of South Florida 

WHOI Woods Hole Oceanographic Institution 
151 

INDEX TO AUTHORS 

Page

Badan, A. ..................................................................................................................................... 57 

Candela, Julio................................................................................................................................ 57 

Donohue, Kathleen ....................................................................................................................... 33 

Hamilton, Peter ....................................................................................................................... 13, 79 

Ko, Dong S. .................................................................................................................................. 95 

Lugo-Fernández, Alexis.................................................................................................................. 7 

Ochoa, J. ....................................................................................................................................... 57 

Pérez Cruz, Guillermo .................................................................................................................... 1 

Sheinbaum, J. ............................................................................................................................... 57 

Toole, John.................................................................................................................................. 107 

Watts, D. Randolph....................................................................................................................... 33 
153 

ATTENDEES 

Allee, Rebecca 

NOAA Gulf Coast Services Center 

c/o NDBC 

Building 1100, Room 360 

Stennis Space Center, MS 39529 

becky.allee@noaa.gov 

Allen, John 

Oregon State University 

College of Oceanic & Atmospheric Sciences 

104 COAS Administration Bldg. 

Corvallis, OR 97331 

jallen@coas.oregonstate.edu 

Anderson, Steven 

Horizon Marine, Inc. 

15 Creek Road 

Marion, MA 02738 

steve@horizonmarine.com 

Arteaga, Patricia 

UNO Conference Services 

New Orleans, LA 70148 

Babin, Stuart 

T. Baker Smith, Inc. 

412 South Van Avenue 

Houma, LA 70363 

stuartb@tbsmith.com 

Badan, Antonio 

CICESE 

Departamento de Oceanografia Fisica 

Apartado Postal 2732 

Ensenada, BC 22860 

abadan@cicese.mx 

Bernard, Landry 

National Data Buoy Center 

1100 Balch Blvd. 

Stennis Space Center, MS 39529 

landry.bernard@noaa.gov 

Biggs, Douglas 

Texas A&M University 

Department of Oceanography 

TAMU Mail Stop 3146 

College Station, TX 77843-3146 

dbiggs@ocean.tamu.edu 

Bohannon, Christy 

MMS 

1201 Elmwood Park Blvd., MS 5200 

New Orleans, LA 70123-2394 

christy.bohannon@mms.gov 

Boland, Gregory 

MMS 

1201 Elmwood Park Blvd. 

New Orleans, LA 70123-2394 

gregory.boland@mms.gov 

Bourg, Donna 

MMS 

1201 Elmwood Park Blvd., MS 5430 

New Orleans, LA 70123-2394 

donna.bourg@mms.gov 

Candela, Julio 

CICESE 

Km 107 Carretera Tijuana-Ensenada 

Ensenada, BC 22860 

jcandela@cicese.mx 
154 

Carnes, Michael 

Naval Research Laboratory 

Code 7332 

Stennis Space Center, MS 39529 

Michael.Carnes@nrlssc.navy.mil 

Christopher, Joe 

MMS 

1201 Elmwood Park Blvd., MS 5400 

New Orleans, LA 70123-2394 

joseph.christopher@mms.gov 

Coelho, Emanuel 

USM 

1020 Balch Blvd. 

Stennis Space Center, MS 39522 

coehlo@nrlssc.navy.mil

Conlee, Don 

NortekUSA 

1100 Balch Blvd. 

Picayune, MS 39466 

don@nortekusa.com 

Coomes, Carol 

Evans-Hamilton, Inc. 

4608 Union Bay Place NE 

Seattle, WA 98105 

adcp@evanshamilton.com 

Cox, Jeffrey 

Evans-Hamilton, Inc. 

4608 Union Bay Place NE 

Seattle, WA 98105 

jeff@evanshamilton.com 

Current, Carole 

MMS 

1201 Elmwood Park Blvd., MS 5433 

New Orleans, LA 70123-2394 

carole.current@mms.gov 

DiMarco, Steven 

Texas A&M University 

Department of OCNG 

3146 TAMU 

College Station, TX 77843-3146 

sdimarco@tamu.edu 

Fan, Shejun 

Fugro GEOS 

6100 Hillcroft 

Houston, TX 77081 

s.fan@geos.com

Galt, Jerry 

Genwest 

12512 Huckleberry Lane 

Arlington, WA 98223 

jerryg@genwest.com 

Guinasso, Jr., Norman 

Texas A&M University 

GERG 

833 Graham 

College Station, TX 77845 

norman@gerg.tamu.edu 

Hamilton, Peter 

SAIC 

615 Oberlin Road, #100 

Raleigh, NC 27605 

Hamilton@saic.com 

Hogan, Patrick 

Naval Research Lab 

Oceanography Division, Code 7323 

Stennis Space Center, MS 39529 

hogan@nrlssc.navy.mil 

Huang, Chester 

MMS 

1201 Elmwood Park Blvd. 

New Orleans, LA 70123-2394 

chester.huang@mms.gov 
155 

Inoue, Masamichi 

LSU Coastal Studies Institute 

331 Howe-Russell Geoscience Complex 

Baton Rouge, LA 70803-7527 

coiino@lsu.edu 

Islam, Quazi 

MMS 

1201 Elmwood Park Blvd. 

New Orleans, LA 70123-2394 

quazi.islam@mms.gov 

Jennings, Grant 

Teledyne RD Instruments 

14020 Stowe Drive 

San Diego, CA 92127 

gjennings@teledyne.com 

Jochens, Ann 

Texas A&M 

Department of Oceanography 

3146 TAMU 

College Station, TX 77843-3146 

ajochens@tamu.edu 

Johnson, Walter 

MMS 

381 Elden Street, MS 4041 

Herndon, VA 20170 

walter.johnson@mms.gov 

Ko, Dong-Shan 

Oceanography Division 

Naval Research Lab 

Stennis Space Center, MS 39529 

ko@nrlssc.navy.mil 

Kosro, P. Michael 

Oregon State University 

College of Oceanic & Atmospheric Sciences 

104 COAS Administration Building 

Corvallis, OR 97331-5503 

kosro@coas.oregonstate.edu 

Lai, Ronald 

MMS 

381 Elden Street, MS 4041 

Herndon, VA 20170 

Ronald.Lai@mms.gov 

Leben, Robert 

University of Colorado at Boulder 

431 UCB 

Boulder, CO 80309 

leben@ccar.colorado.edu 

Leedy, Herb 

MMS 

1201 Elmwood Park Blvd. 

New Orleans, LA 70123-2394 

daniel.leedy@mms.gov 

Lugo-Fernández, Alexis 

MMS 

1201 Elmwood Park Blvd. 

New Orleans, LA 70123-2394 

Alexis.LugoFernandez@mms.gov 

Magnell, Bruce 

Woods Hole Group, Inc. 

81 Technology Park Drive 

East Falmouth, MA 02536 

bmagnell@whgrp.com 

McDonald, Dan 

T. Baker Smith, Inc. 

412 South Van Avenue 

Houma, LA 70363 

McKone, Kevin 

LSU CMI Post Doc 

Copiah Lincoln College 

1614 Enterprise Rd. SE 

Bogue Chitto, MS 39629 

Kevin.mckone@colin.edu 
156 

Merrell, Bill 

Texas A&M at Galveston 

Department of Marine Biology 

5007 Avenue U 

Galveston, TX 77551 

merrellw@tamug.edu 

Metcalf, Margaret 

MMS 

1201 Elmwood Park Blvd. 

New Orleans, LA 70123-2394 

margaret.metcalf@mms.gov 

Michelet, Denise 

UNO Conference Services 

New Orleans, LA 70148 

dmichele@uno.edu 

Mooers, Christopher 

OPEL/RSMAS 

University of Miami 

4600 Rickenbacker Causeway 

Miami, FL 33149-1098 

cmooers@rsmas.miami.edu 

Moore, Andrew 

University of California Santa Cruz 

1156 High Street 

Santa Cruz, CA 95062 

ammoore@ucsc.edu 

Morey, Steven 

Center for Ocean-Atmospheric 

 Prediction Studies 

Florida State University 

Tallahassee, FL 32306 

smorey@coaps.fsu.edu 

Nowlin, Worth 

Texas A&M University 

Department of Oceanography 

3146 TAMU 

College Station, TX 77843-3146 

wnowlin@tamu.edu 

Oey, Leo 

Princeton University 

AOS Program 

14 Taunton Court 

Princeton Junction, NJ 08550 

lyo@princeton.edu 

Peggion, Germana 

University of New Orleans 

Bldg. 1009C 

Stennis Space Center, MS 39529 

gpeggion@uno.edu 

Pérez Cruz, Guillermo 

PEMEX 

Torre Empresarial Piso 12 

Col. Fracc.Lindavista Villahermosa 

Tabasco, CP 86050 

gperez@pep.pemex.com

Perez-Brunius, Paula 

CICESE 

KM 107 Carretera Tijuana-Ensenada 

Ensenada, BC 22860 

brunius@cicese.mx 

Powell, Brian 

University of California Santa Cruz 

1156 High Street 

Santa Cruz, CA 95062 

powellb@ucsc.edu 

Precht, William 

7310 Poinciana Court 

Miami Lakes, FL 33014 

Bill.Precht@noaa.gov 

Ramos, Rafael 

Woods Hole Group 

University of Miami 

4600 Rickenbacker Causeway 

Miami, FL 33149 

rramos@rsmas.miami.edu
157 

Raye, Robert 

Shell Inc. 

3737 Bellaire Blvd. 

Houston, TX 77025 

robert.ray@shell.com 

Roscigno, Pasquale 

MMS 

1201 Elmwood Park Blvd. 

New Orleans, LA 70123-2394 

Pasquale.Roscigno@mms.gov 

Rouse, Lawrence 

LSU Coastal Marine Institute 

Howe-Russell Geoscience Complex 

Baton Rouge, LA 70776 

lrouse@lsu.edu 

Schimtz, William 

Texas A&M at Corpus Christi 

Harte Research Institute 

5420 Stonegate Way 

Corpus Christi, TX 78411 

wschmitzjr@stx.rr.com 

Shay, Lynn 

RSMAS 

University of Miami 

4600 Rickenbacker Causeway 

Miami, FL 33149 

lshay@rsmas.miami.edu 

Sheinbaum, Julio 

CICESE 

Ensenada, BC 22860 

julios@cicese.mx 

Silva-Ballesteros, Jorge 

Instituto Mexicno del Petroleo 

Eje Central Lazaro Cardenas No. 152 

Col. San Bartolo Atepehuacan 

C.P. 07730, México D.F. 

jsilvab@imp.mx 

Sturges, W. "Tony" 

Florida State University 

Department of Oceanography 

Tallahassee, FL 32306-3048 

sturges@ocean.fsu.edu 

Teague, William 

Naval Research Laboratory 

Code 7332 

Stennis Space Center, MS 39529-5004 

teague@nrlssc.navy.mil 

Toole, John 

WHOI 

Department of Physical Oceanography 

354 Clark Laboratory 

Woods Hole, MA 02543 

jtoole@whoi.edu 

van Smirren, Jan 

Fugro GEOS 

P.O. Box 740010 

6100 Hilcroft 

Houston, TX 77081 

j.smirren@geos.com 

Vigil, Debra 

MMS 

1201 Elmwood Park Blvd. 

MS 5431 

New Orleans, LA 70123-2394 

debra.vigil@mms.gov 

Waddell, Evans 

SAIC 

615 Oberlin Road, Suite 300 

Raleigh, NC 27605 

evans.waddell@saic.com 

Walker, Nan 

LSU Coastal Studies Institute 

Howe-Russell Geoscience Complex 

Baton Rouge, LA 70803 

nwalker@lsu.edu 
158 

Wang, Dong-Ping 

State University of New York 

 at Stony Brook 

Marine Sciences Research Center 

Stony Brook, NY 11794 

Dong-Ping.Wang@stonybrook.edu 

Watts, Randolph 

University of Rhode Island 

Grad. School of Oceanography 

215 South Ferry Road 

Narragansett, RI 02882 

rwatts@gso.uri.edu 

Weatherly, Georges 

Department of Oceanography 

Florida State University 

Tallahassee, FL 32306-4320 

weatherly@ocean.fsu.edu 

Weisberg, Robert 

College of Marine Science 

University of South Florida 

St. Petersburg, Florida 33701 

weisberg@marine.usf.edu 

Welsh, Susan 

LSU Coastal Studies Institute 

331 Howe-Russell Geoscience Complex 

Baton Rouge, LA 70803 

swelsh@lsu.edu 

Yetsko, Chris 

Fugro GEOS 

6100 Hillcroft 

Houston, TX 77081 

c.yetsko@geos.com 
The Department of the Interior Mission

As the Nation's principal conservation agency, the Department of the Interior has responsibility 

for most of our nationally owned public lands and natural resources. This includes fostering 

sound use of our land and water resources; protecting our fish, wildlife, and biological diversity; 

preserving the environmental and cultural values of our national parks and historical places; 

and providing for the enjoyment of life through outdoor recreation. The Department assesses 

our energy and mineral resources and works to ensure that their development is in the best 

interests of all our people by encouraging stewardship and citizen participation in their care. 

The Department also has a major responsibility for American Indian reservation communities 

and for people who live in island territories under U.S. administration. 

The Minerals Management Service Mission 

As a bureau of the Department of the Interior, the Minerals Management Service's (MMS) 

primary responsibilities are to manage the mineral resources located on the Nation's Outer 

Continental Shelf (OCS), collect revenue from the Federal OCS and onshore Federal and Indian 

lands, and distribute those revenues. 

Moreover, in working to meet its responsibilities, the Offshore Minerals Management Program 

administers the OCS competitive leasing program and oversees the safe and environmentally 

sound exploration and production of our Nation's offshore natural gas, oil and other mineral 

resources. The MMS Minerals Revenue Management meets its responsibilities by ensuring the 

efficient, timely and accurate collection and disbursement of revenue from mineral leasing and 

production due to Indian tribes and allottees, States and the U.S. Treasury. 

The MMS strives to fulfill its responsibilities through the general guiding principles of: (1) being 

responsive to the public's concerns and interests by maintaining a dialogue with all potentially 

affected parties and (2) carrying out its programs with an emphasis on working to enhance the 

quality of life for all Americans by lending MMS assistance and expertise to economic 

development and environmental protection.