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Appendix E: Working Group 1: Wind, Wave, and Swell JON F. KLEIN, Sea-Land Service, Inc., Leader VINCENT J. CARDONE, Oceanweather Inc. FORREST ~ MILLER, Inter-American Topical Gina Commission D. B. MAO, National Meteorological Center, National Oceanic Atmospheric Administration ALLAN M. REECE, Shell Development Company WILLIAM S. RICHARDSON, National Ocean Service, National Oceanic Atmospheric Administration SOURCES OF FORECAST INFORMATION AND DATA The group identified four major sources of wind, wave, and swell data: U.S. Air Force, U.S. Navy, NOAA, and all foreign centers (taken collectively). The Air Force was not given detailed consideration since their global forecast center operates atmospheric models only. Addition- ally, the Air Force does not generally release data to the public sector. Although foreign sources may play a greater role in forecasting in the fu- ture as exchanges of forecast products increase in number, this interaction is presently limited in scope. Therefore, detailed consideration of foreign source data was not pursued by the working group. The U.S. Navy Fleet Numerical Oceanography Center (FNOC) pro- vides the Navy with a comprehensive array of marine forecasts. Most of this information is directed toward satisfaction of the Navy's internal operating requirements. Selected FNOC products, including global and regional wind and wave analysis and forecasts, are distributed in real-time transmissions 64
65 to the civilian sector through CNODDS and Radiofax. The information released by FNOC consists of graphic and tabular output from the Navy's numerical atmospheric weather prediction (NWP) models, its global spec- tral ocean wave model (GSOWM), and its regional Mediterranean spectral ocean wave model (MSOWM). These data require further analysis and interpretation before they can be productively used in site-specific forecast applications. The Navy derives both analyzed and forecast surface-wind data from sophisticated planetary boundary layer formulations in its global (Navy Op- erational Global Atmospheric Prediction System NOGAPS) and regional (Navy Operational Regional Atmospheric Prediction System NOAAPS) prediction systems. This surface-wind information is disseminated to both military and civilian users through a variety of communications links. These wind data are also used to drive the Navy's global and regional wave models. The Navy's global wave model (GSOWM) is a deep-water model that runs on a 2.5° latitude and longitude grid and represents the wave spectrum in 15 frequency and 24 direction bands. The GSOWM produces two forecasts per day extending out 48 and 72 hours. Many output products including sea and swell height, period, and direction are derived from GSOWM spectra and disseminated to various users. MSOWM is a fixst-generation deep-water model run by the Navy covering the Mediterranean area in 70 km grids. The model represents the spectrum in 15 frequency and 12 direction bands. MSOWM also produces two forecasts per day and its spectral data receives dissemination similar to GSOWM. NOAA also operates a global, deep-water ocean wave prediction model. Both the Navy and NOAA models are driven by forecast wind fields derived from different atmospheric models. The wave models them- selves also differ in certain aspects regarding the treatment of the underlying physics. While the Navy's models are designed and operated primarily to satisfy the Navy's internal requirements, NOAA's wave modeling program is an integral part of NOAA's broader ocean products center, which is charged with serving the civilian community. Both the NOAA and Navy models undergo periodic monitoring, validation, refinement, and extension to provide higher resolution and better physical representations. For exam- ple, NOAA has implemented and the Navy is now implementing new wave models that include new physics and shallow-water effects. NOAA produces ocean surface (10 m level) wind forecasts by apply- ing diagnostic boundary layer procedures to the large-scale wind forecast produced by N~C's global atmospheric model. These wind forecasts are provided to National Weather Service (NWS) Forecast Offices (WSFO) us- ing AFOS, AKFAX, and DIFAX. In addition, these forecasts are available on NOAA's Family of Services to all civilian users.
66 The NOAA operational global model is a deep-water model that predicts the two-dimensional wave spectrum on a 2.5° latitude and longitude grid. The model uses parameterized wave-wave interactions and has 15 frequency and 24 directional bands. The forecasts are issued once a day and extend for 72 hours. Output products are in terms of significant wave heights, primary period, and direction and are disseminated to WSFO's and civilian users via the same media mentioned above for wind forecasts. I~o-dimensional spectra messages are also provided by NOAA for selected points along the U.S. coast. As mentioned previously, NOAA has implemented its shallow-water spectral wave model to forecast waves over the Gulf of Mexico. In con- trast to the global ocean wave model, this model takes into account the effects of bottom topography and bottom friction on wave propagation and dissipation. This model uses a 50 km (approximate) grid and is run twice daily to produce forecasts out to 48 hours. The output products, including significant wave heights, primary period, and direction are disseminated via AFOS and FOS. Plans are under way within NOAA to extend this shallow wave model to other U.S. coastal regions during the next 12 months. In addition to dynamically generated wind and wave forecasts, NOAA also produces statistically driven wind and wave forecasts. A model output statistics (MOS) technique provides wind forecasts out to 48 hours at 91 coastal stations and more than 12 Great Lakes regions. Wave forecasts, based essentially on a SMB technique, are provided for 64 points on the Great Lakes and 6 points on the Chesapeake Bay. A summary of the sources of numerical forecast guidance of wind, waves, and swell is provide in Bibles E-1 and E-2 which follow. PERCEIVED USER REQUIREMENTS The working group next attempted to delineate forecast requirements ~ . tor various user groups. These user groups were loosely structured under four areas: coastal, nearshore, high seas, and the military. Requirements were then developed for each user area covering forecast and data param- eters, spatial resolution, temporal resolution, forecast horizon, and delivery medium. In general the working group found that each user group had sig- nificantly different forecast and data requirements. Each user group's requirements are equally critical to that group's needs. As noted in Ta- ble E-3, current marine weather forecasts do not meet these perceived requirements. Coastal users, including recreational boaters and fishermen, commer- cial fishermen, marinas, port authorities, and others, require highly accurate
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68 forecasts covering tight site-specific grids with a forecast horizon of 0 to 12 and 24 hours. Conversely high-seas users, which include ocean shipping, ocean min- ing, commercial fishing, ocean towing, and other groups, require forecasts with a 20 percent accuracy factor, covering a grid of approximately 150 nautical miles and extending from 24 to 72 hours out to 6 to 10 days. The nearshore users, which include the oil and gas industry, coastal shipping, waste disposal, commercial fishing, and other groups, have per- ceived requirements falling in-between the coastal and high-seas groups. The military's requirements span all three geographic areas and include other special mission oriented requirements. The working group concluded that none of the perceived require- ments for coastal users were being met, although a significant value-added effort using existing data could result in a marked improvement in coastal forecasts. Additionally, NEXRAD (NOAA's coastal radar program) will provide valuable data for this area, although it will also require expert interpretation by government or private sector value-added groups before it is useful to civilian end users. The expansion of the GMWAVE model to other coastal ranges during the next year should allow the 50 km spatial requirement of nearshore users to be met, although two-dimensional information will still not be readily available to civilian users. The accuracy requirements of the nearshore user group is currently not being met. With regard to high-seas users, the longer range forecast horizon, which is critical to effective voyage planning, is not being met. There is no formal program to address episodic waves or to implement the perceived need for a real-time warning program for episodic waves. Although covered in detail by another working group, it was felt that certain comments concerning dissemination were appropriate with regard to wind, wave, and swell forecasts. The media through which wind and sea-state analyses flow to the end user fall into three classes: direct data links, NWS, and the private sector. Direct Data Links These links make possible the acquisition of vast amounts of observa- tions and Navy and NOAA analysis and forecast products by the end user. The major limitation of this medium is the restricted or limited usefulness of raw model output for most forecast applications and the limited access to these links from offshore locations. Additionally, in 1985 so many users were accessing the Navy's NODDS data link that the system was failing. 16 protect the system, civilian access was discontinued. In an effort to main- tain civilian access to this data, NOAA established the CNODDS program
69 - - In c - m B U] o to to o ~ · be O · ~ CO ~ 0, C ° Its 3 ~ ~ ~ ~ al °O . - ~ en so It o .~ .o~ o C} ~ = ·= U ~ o Z _ ~ ~5 <'=:~ lit 3 o `,,- ~ o ~ :Z ~ · ~ ~ ~ CQ v w o w 3 ~ o To ~ <,, Pt ¢ c. V ~ ~ ~ V P. en ~ o, OQ al ~ o . ~ ~ v ¢ o v 3 a D3 h `_ O ; o ~ o °,s 6_,~C X ~ o b ~q ~ ° U] · o ._ q) U' · V ~: ~ .~= ~ ~ O ,. ._ o _ ~. ~ ~C =-c ~.b0-L, o g 410 · ~ L. V, .O · V 4u ~ ~ o o 3." P~ =-c ~.~-L, o . o ~0 ~w ~ CQ ¢ U) ._ s" ~ O ._ ,, ._ ~ 1v') ,,, _ .o ,= ,,, O _ ~ ~ C ·) g o O - o ._ &_ ~ cn ~0 O ~ :^ ~ _ - · - - ~ ~ 3 ~ o ~ ~ r-~ ~ ¢ o ~ - · ~.
70 without additional funding. NOAA's long-term goals are to make all non- classified Navy products available through its Family Of Services program and discontinue its CNODDS program. National Weather Service The National Weather Service is the major source of user friendly fore- cast information. NWS offices provide coastal forecasts, offshore forecasts, and high-seas forecasts as well as gale and storm and special marine warn- ings. Under NOAA, the NWS attempts to meet user requirements within tight budgetary constraints and physical limitations of modeling data and other resources. In addition to the above example, the Navy has announced its intention to discontinue its East Coast facsimile (FAX) transmissions to the civilian sector. These are the primary source of forecast data for many commercial fishermen and nearby coastal shipping. NOAA must now step in and assume these transmissions, without additional funding, or this valuable information will be lost. Private Sector One area of the private sector, also known as "data brokers," typically operate as redistribution centers for graphical, satellite, and radar imagery, as well as alphanumeric data. This information is mainly acquired from NOAA's Family of Services facility at Suitland, Maryland, and via NEDIS (direct satellite data). The information provided by data brokers is modified in format but not content. The value-added component of the private sector is a more varied mix of companies. Some provide very specific local forecasts, such as the dial-up surf forecasts available in southern California. Others provide site- specific wind and wave forecasts to contracted offshore oil and gas industry facilities, while a small number of companies provide high-seas forecasts to contracted companies in the form of voyage routing services. A very small sector of the value-added group have demonstrated ded- icated area and application specific computer-assisted wind and wave fore- cast systems incorporating human input for interpretation, quality control, and accuracy enhancement. Other very small segments have recently demonstrated "expert" type systems that utilize on-board microprocessors and incorporate forecast wind and wave information along with vessel stability criteria to assist in decision making with regard to optimum routing, seakeeping, and damage avoidance.
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72 CONCLUDING REMARKS ON BENEFITS Members of each identified user group feel meeting their specific forecast requirements is critically important for reasons of safety and eco- nomics. In the highly competitive high-seas market, a high benefit-to-cost ratio can be expected due to the level of potential savings in industries with very high fixed costs. This ratio is offset somewhat by the fact that the high-seas region has a relatively small population. Solutions to meet the perceived requirements of the nearshore users group will also have a relatively high unit cost. The nearshore constituency is considerably larger than the high-seas constituency, and there are also significant benefit factors to be considered relative to the impact of im- proved forecast on environmental issues within the oil, gas, and waste disposal industries. It was the working group's conclusion that the coastal region would likely derive the greatest benefit of meeting perceived forecast require- ments. This benefit is measured in terms of protecting the lives and property of an ever-growing group of small boat operators, fishermen, and individuals engaged in other activities in this heavily populated con- stituency. Although meeting perceived requirements in this region will result in a low unit cost benefit, the total bottom-line benefit is greatest due to the overwhelming size of the coastal constituency. ATTENDEE COMMENTS The working group presented its preliminary findings on the last day of the workshop in Irvine, California, on September 29, 1988. Following this presentation, several attendees submitted written comments concerning the forecasting of wind, waves, and swell. The group did not meet again following its presentation and could not fully incorporate the submitted comments into its report. The author has, therefore, highlighted these comments to ensure that these comments are taken into account by the committee in preparing its final report. A fishing industry representative (Atlantic and Gulf areas) stressed heavy dependence on FAX transmissions of wave heights and other data used in performing analysis at sea. There was a great deal of concern that regularly scheduled FAX transmissions not be discontinued. A routing service manager from the value-added sector addressed the hazard of superstructure icing and its related forecast requirements. Superstructure icing is an extreme hazard when it occurs. It is presently forecast by means of a nomogram with entries including estimated air temperature, surface wind speed, sea temperature, and the duration of the event. The output is a forecast of anticipated superstructure icing in
73 centimeters. The manager commented that the nomogram highly depends on the output of surface forecasts (except sea temperature) and could benefit greatly from improved forecast data. A shipping company executive addressed the perceived need for dis- seminating more information regarding episodic waves and recommended implementation of some form of a real-time warning system for these dangerous wave systems. An oil industry representative offered the opinion that "with the ex- ception of the observation of sea ice, remote sensing technology is not in the position of making much additional contribution to the ocean data base in a reasonably near-term time frame." He went on to point out that exper- imental programs in this area are valuable and deserving of consideration for support, but should not receive an inappropriate amount of emphasis. A U.S. Coast Guard (USCG) representative added the following com- ments concerning perceived needs applicable to USCG operation. · Highly accurate forecast information including wind drift is re- quired for the coastal and nearshore areas to support oil and waste spill containment and cleanup operations. · This same highly accurate forecast information is also required to support search and rescue missions with specific needs in the area of wind drift predictions of drifting boats and objects and to support the decision-making process as to what equipment (e.g., boat size, helicopters) to allocate to rescue missions. · Highly accurate wind and sea-state forecasts are required to prop- erly plan buoy placement and tending operations. Accurate wind drift forecasts are needed to support ice operations in both the nearshore and high-seas areas. · Regarding the USCG's military mission it was pointed out that accurate wind and wave forecasts are required to plan and execute port approach operations, that is, minesweeping. · Spatial resolution, temporal resolution, forecast horizon, and ac- curacy requirements were detailed in the USCG's comments and covered all ranges of the perceived requirements outlined Table E-2 (depending on the area and specific mission application). An unidentified attendee remarked on his perceived need for a strate- gically located network of fixed platforms and data buoys within 300 miles of the coast. He felt this network would significantly improve wind data gathering and wave prediction and modeling. He felt this network could fill the need in this area until an operational all-weather satellite was avail- able to provide this data, and after such a satellite became operational the network could serve as a backup to the satellite and assist in calibration operations.