The GCOOS Mooring Plan Element Draft, 19 February 2011

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1 The GCOOS Mooring Plan Element Draft, 19 February Introduction In order to proceed with the establishment of a regional coastal ocean observing system for the Gulf of Mexico, it is essential to have plans for the components comprising that system. Those components include, among others, an HF Radar system, an integrated Harmful Algal Bloom observing system, a system of sea level measurements and a system of moored buoys. This document is a draft plan for measurements made from moorings. It has been based on inputs from current mooring operators in the Gulf, from HF Radar operators, from model developers and others, but it certainly is subject to modification based on new knowledge, experience, and changes in technology and costs. Assumptions Consider only moorings for velocity, T, S, waves and met measurements. Do not include instrumentation useful on the moorings for other elements (e.g., HABS, hypoxia,...) Do not include moorings used in PORTS Do not include stations intended primarily for water level measurements even if they include met measurements etc. Deficiencies Does not include industry and CMAN stations making met measurements Cost estimates are likely too low and need another look This document is deliberately short. Section 2 gives design considerations. Section 3 describes and pictures the preliminary design. Cost estimates are given in Section 4. The final section gives Nowlin s personal prioritization for implementation. 2. Design Considerations We first consider points relative to the uses and placement of moorings in the Gulf of Mexico regional coastal ocean observing system. This discussion is divided between the shelves and the deeper water portions of the Gulf. 2.1 Shelf Moorings Correlation scales have been shown to be of order 15 km across- shelf and km along- shelf. Hence, it is totally impractical to sub- sample such motions. Their monitoring must be carried out by the use of HF Radar. We might consider three sub- regions of the shelf. The outer shelf extends from the shelf break inshore some km. The inner shelf is the region of intersecting surface and bottom Ekman layers resulting in wind- driven along shelf currents and is also affected by freshwater stratification. The mid shelf separates the inner and outer shelf regions. On narrow portions of he shelf this may not exist.

2 2.1.1 Inner and mid shelf moorings Much of the inner and mid shelf will be covered by HF Radars measuring surface currents and waves. However there remain needs to locate moorings at the following locations: Near ship channels and in difficult navigation areas, Near the limits of radar coverage to maintain information where radar coverage is poor and to verify retrieved radar estimates of currents and waves, and At regular intervals in cross- shelf arrays to monitor vertical structure and property distributions of major wind and density driven currents. Cross Shelf Moorings should have temperature and salinity measurements at the surface, mid depth and bottom, as a minimum. This can be achieved using MicroCats with inductive links. The trade off of these measurements would be that the maintenance interval may be reduced resulting in elevated O & M Due to the blanking on ADCPS buoys should be fitted with a single point current meter to collects data as close to the surface as possible as this will be required for intercomparioson with HF Radar data, All moorings near shore should measure directional waves because radar- derived wave signatures could benefit from careful verification with direct observations Outer shelf moorings This is the critical region for interactions between deepwater circulation features (e.g., Loop Current, Loop Current Eddies, cyclonic eddies) and the circulation and property distributions over the shelf. Large on- or off- shelf water exchanges can occur, drastically altering properties over the shelf Air- sea flux monitoring along the shelf break will enhance capability for predictions (atmospheric circulation, weather, storm intensity). Air- sea interaction buoys (with full suites of improved meteorological measurements developed by Robert Weller et al. in the late 1980s) should be placed along the shelf edge perhaps seven to complement the NDBC buoys, Data would be compared with bulk estimates and with numerical weather prediction and other model results when not used in those models The same shelf- edge buoys, as well as the four NDBC buoys, should be equipped with acoustic Doppler current profilers (ADCPs) and vertical arrays of temperature and conductivity sensors. 2.2 Continental Slope and Deepwater Moorings Velocity profiles as well as temperature and perhaps conductivity are needed from locations distributed throughout the deepwater Gulf, including the slope. These will be used to monitor the movement and property distributions of major circulation features. In general (with the exception of the surface Ekman layer) currents are coherent over the upper m of the water column; flow features below that level may be quite different and are frequently intensified toward the bottom. Therefore, monitoring should extend through the water column. These measurements are needed to verify and constrain numerical circulation and other ocean models, to alert commercial operators regarding current conditions and may be used to track the distribution of substances released into the deep Gulf.

3 Deepwater oil & gas exploration and production is proceeding between ~88 W 94 W. The federal government mandates that exploration and production platforms production near real time vertical profiles of currents through the upper water column using downward- looking ADCPs. Data are publically available via the National Data Buoy Center (NDBC). It should be possible to enhance measurements made on some of these platforms by adding upward looking ADCPs in the lower water column and a string of temperature- conductivity sensors along the signal/power cables leading down to the ADCPs. Based on the experiences of a number of operators who have tried to do this it is ill- conceived and therefore propose that we remove this requirement for temperature/ conductivity sensors from the proposal. The only case where this may be reasonable would be on new build structures, but would still be a very costly solution buoys and gliders are a better option. Also upward looking ADCPs on the Seabed can be very problematic and Acoustic telemetry unreliable due to background noise, therefore upward looking ADCPs can be twinned with the existing NDBC and new assets Enhanced capability industry platforms Approximately eight of the industry platforms should be enhanced to include deeper profiles of currents and discrete measurements of temperature and conductivity through the water column. See above Needed new assets Four deepwater moorings, with aforementioned capability, should be added to the west or south of the enhanced industry platforms, and seven moorings should be added east of the industry platforms. These moorings also should have standard meteorological packages and wave sensors. Drawing has been revised to add the additional mooring. And deepwater upward looking ADCPs with acoustic telemetry General Integrating Considerations It is important to note that other measurements should be included on these mooring as required for other purposes. Examples are measurements for monitoring hypoxia, harmful algal blooms, the carbon cycle, or ecosystem parameters. The costs for those measurements have not been included in this plan. 3. Preliminary Design Note: All data should be transmitted to on shore processing facilities within a maximum of 30 minutes after measurements are made. 3.1 Existing moorings operated by the NDBC and by non- federal groups should be upgraded in terms of sensing capability and data transmission. The locations of these moorings are shown on the map in Figure 2. Different symbols designate different operators: T = TABS; N = NDBC; W = WAVCIS; C = COMPS, L = LUMCON; and D = Dauphin Island Marine Laboratory.

4 Figure 2. Draft GCOOS Mooring Location Map 3.2 Deepwater moorings are in two classes We plan for eight (8) oil and gas industry deepwater platforms to be enhanced as described in section These will be located within the area in which industry platforms are operating; that area is indicated in Figure 2 by shading We plan for eleven (11) new deepwater moorings as described in section to be placed at approximately the locations shown in Figure Shelf- edge moorings The positions of the seven new shelf- edge moorings are shown in Figure 2. As seen, these would be complemented by the three NDBC buoys located near the shelf edge, although, the NDBC moorings would not have sophisticated air- sea flux measuring sensors. 3.4 Cross- shelf mooring arrays There are two categories of cross- shelf arrays. Category 1 makes maximum use of extant assets and of new shelf- edge moorings. These arrays are indicated by solid lines in Figure 2 and should be implemented first. Category 2 cross- shelf arrays, indicated by dashed lines in Figure 2, are intended to complete the inner and mid shelf array of moorings. On each cross- shelf array as attempt has been made to locate moorings near or on the following isobaths: 200, 100, 30, and 10 m. 3.5 Moorings near ship channels and in difficult navigation regions Locations of these moorings have not been specified. Rather, we include as an initial estimate the need for fifteen shallow water (depths to about 10 m) buoys capable of measuring near surface velocity, temperature and conductivity (assumed at this time to be based on the current system attached to existing navigation buoys, which reduces both capital and maintenance costs). We also

5 include ten buoys capable of measuring in water depths up to 50 m surface velocity, temperature, conductivity, directional waves and winds as well as vertical profiles of horizontal currents. 4. Cost estimates Here we begin with the costs of extant mooring assets. Then we give costs for needed new assets, beginning with the assets needed in the deepwater Gulf and then progressing to needs for monitoring near ship channels and in difficult navigation areas. I have asked a number of people indicated in the text to review these costs. To make this simpler I have constructed a spreadsheet, which I attach, I request that each Volunteer review and revise the spreadsheet as appropriate 4.1 Costs of upgrading and maintaining current non- federal assets TABS To upgrade TABS I buoys to measure current profiles, winds and waves would cost $880K. To upgrade TABS II buoys to 2.25 M buoys with full capability would cost $1,400. To prepare spares for existing 2.25 M buoys would cost $520K. The total upgrade costs would be $2,800K. Annual operating costs would be $1,220K year WAVCIS Upgrades would cost ~ $300K Annual operating costs would be ~ $980K per year COMPS Upgrades to extant equipment would cost ~ $ 1,260K. Annual operating costs needed are ~ $800K LUMCON Annual operating costs estimated at $200K DISL Including upgrades for real- time data transmission, the total costs in year one would be $278K for year one and $167K per year for continuing operation USM The cost to upgrade the mooring would be $60K. The annual cost is approximately $120K Costs of upgrading and maintaining current federal assets The costs of upgrading ten moorings to include ADCP and temperature/conductivity strings is estimated to be ~ $660K. The costs of annual operating costs of existing equipment is not included because they already are included in the federal budget TOTAL costs of existing moorings: Costs of initial upgrades $5,358K Annual operating costs $3,487K 4.2 Costs of deepwater moorings The cost of enhancing industry platforms will be ~ $85K each, for a total cost of $680K. Industry will be expected to maintain the equipment. However an annual replacement and upgrade cost of ~ $68K will be needed.

6 The costs of added assets will be ~ $390K per buoy and $240K per hear for operation and replacement and upgrades. For ten buoys the cost will be $3,900K for assets and $2,400K for operation. Total for deepwater moorings: $4,580K $2,468K 4.3 Costs of shelf- edge moorings The cost for each of the shelf- edge moorings would be $330K with temperature and conductivity string, ADCP, waves and surface water properties. The cost of an IMET system with data transmission to measure surface fluxes would be $83K per buoy, installed and calibrated. Thus, the seven new moorings would cost $2,891K, and annual operating costs would be ~ $1,400K. Modifying the NDBC moorings to include a vertical string of temperature and conductivity sensors and a full depth ADCP would cost ~ $ 270K for the three. Total for shelf- edge moorings: $3,161K $1,400K 4.4 Costs of cross- shelf arrays This cost estimates are based on the incorporation of extant assets and shelf- edge moorings into the cross- shelf arrays. Category 1 arrays will require ten TABS II buoys plus three spares at $120K each and seven 2.2- m buoys plus three spares at $260K each. Total costs for category 1 cross- shelf arrays: $4,160K $1,700K Category 2 arrays will require four plus one spare 2.2- m buoy with ADCP at $290K each, five plus two spare 2.2- m buoys with 100 m ADCP at $260K, and nine plus three TABS II buoys at $210K each. Total costs for category 2 arrays: $5,790K $2,160K Total costs for cross- shelf arrays $9,950K $3,860K 4.5 Costs of moorings for channels and difficult navigation regions Ten shallow water (TABS I) each would cost $300K. The intermediate depth moorings cost $120K each for a total of $1,200K.

7 Total costs: 4.6 TOTAL COSTS TOTAL $1,500K $1,000K $24,549K $12,215K $36,764K Note these estimates do not include currently budgeted federal, state, or industry funds being used for operations or maintenance costs for instrumentation deployed on oil and gas industry platforms. 5. Implementation Priority The sub- arrays of this mooring plan are divided here into priority order for implementation. This selection is attributed to Worth Nowlin. 1 is the sub- array of highest priority; 2 is the sub- array of next highest priority; etc. 1. Upgrades and continuation of extant moorings: Clearly, the first item of business is to bring existing assets up to needed capabilities and to maintain their operation. 2. Category 1 cross- shelf arrays: If these arrays are implemented prior to all of the shelf- break moorings, it will be necessary to implement some of the shelf- break moorings to complete the cross- shelf arrays. 3. Moorings for channels and difficult navigation regions 4. Deepwater moorings: This implementation should begin with enhancements to the industry platforms. 5. Category 2 cross- shelf arrays 6. Shelf- edge array 6. Planning Team Members The team that developed the plan for this element is identified in Table 1. Table 1. Development Team Members Name Affiliation Expertise Richard Crout NOAA, NDBC NDBC Assets, buoy technology and Data Management Cort Cooper Chevron Oil industry capabilities, and requirements Kyeong Park Dauphin Island Marine HABS, coastal requirements Laboratory Mark Luther USF Bouy and sensor technology, COMPS, Florida Ports Buzz Martin TGLO TABS Network, Oil Spill Response Steve DiMarco TAMU TABS Network, research activities and requirements Worth Nowlin TAMU GCOOS, Observational requirement in the Gulf, HABS Stephan Howden USM HF Radar Alan Lewitus NOAA Hypoxia, Alexis Lugo Fernandez BOEMRE BOEMRE requirements, Gulf research, NTL measurement programs Jan van Smirren Fugro Oil industry capabilities, and requirements An initial draft plan was prepared in July 2010 by Worth Nowlin with information inputs from Nick Shay, Chris Mooers, Norman Guinasso, Robert Weller, Robert Weisberg, and Cort Cooper.