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OTHER OCEAN CLIMATE RESEARCH ISSUES So far this report has reviewed the large-scale programs that seem to have the blessings of national and international planners. In this chapter, some ocean climate studies that may fall outside this framework are first reviewed. Then the advantages of bilateral (as opposed to broad international) ocean climate research work with other countries are considered. The chapter concludes with a discussion of common observational and modeling needs. OCEAN CLIMATE RESEARCH OUTSIDE THE BIG PROGRAMS The large, internationally sanctioned ocean climate programs receive most of the attention, here as elsewhere. Yet a number of competent ocean scientists concerned with the climate variability problem are not convinced that they should work within the big programs. Oceanography has a tradition of independence. Some oceanographers interested in climate are reluctant to relinquish that independence in order to work within the large programs. Ocean climate research is concerned, by definition, with global scientific questions. Can they be effectively addressed by independent studies? The easy course of action, and one that is not hard to defend, is to insist that oceanographers (and perhaps meteorologists) work together in addressing world climate and the world ocean. Nevertheless, many ocean scientists who lack the taste for big programs have good ideas with the potential to make progress in understanding climate. These ideas should not be excluded because their authors prefer not to work in big science. Whatever decisions are made about the big programs, NSF should continue to be flexible enough to support good ocean climate research ideas even when they are outside the "approved" framework. Some oceanographers contend that global ocean climate planning is overblown and perhaps even unrealistic, that it does not take account of the difficulties in obtaining reliable data in the field, and that a better description of the ocean's structure and circulation is needed before we 44
45 can move on to understanding the ocean's role in climate. They argue for simpler field programs. There is concern too, that we must not begin a large costly global program before we are scientifically and technically ready to carry it off well. If we were to try prematurely and fail, it is likely that the funds to do it right would be a long time in coming. A number of ideas for ocean climate research outside of the official programs have been presented that could improve our knowledge of climate variability. Some of these ideas may end up as components of the big programs (like WOCE) as the planning for these programs evolves. Among the ideas are the following: * Make a few long, deep hydrographic sections intended to provide a base of information about interior low- frequency ocean movements and dynamics (see the discussion of the Long Lines program below). * Maintain and perhaps extend island tide stations in the western Pacific Ocean. * Maintain the Pacific XBT monitoring program, TRANSPAC (White and Bernstein, 1979). * Carry out some small experiments to understand the physical processes that are important components in climate, such as air-sea fluxes of heat, water, and momentum. Some ocean studies that may be important are less fashionable. Few oceanographers are studying the polar regions. Is the role of the ice-covered regions in climate variability receiving enough attention? This question has been reviewed (ICEX Science and Applications Working Group, 1979), but there has been little follow-up. Some large-scale oceanographic studies have been developed outside the climate program, and their results could benefit our understanding of climate variability. In a sense, most of physical oceanography could be tied to climate research. We have to decide where to draw the line. By including too much under the climate umbrella, we risk weakening the focus of the ocean climate research program. Yet we should note the importance to climate research of many ongoing and proposed ocean research programs, such as the following: Transient Tracers in the Ocean (TTO) has as its primary objective to determine the flux of fossil fuel carbon dioxide into the ocean and to predict its distribution through an understanding of ocean circulation.
46 Using chemical tracers such as tritium (hydrogen-3) and carbon-14, TTO will study ocean circulation and mixing. The results should test the ability of numerical ocean circulation models to predict ocean transport on time scales of decades and longer. Studies of climate variability on interannual time scales will benefit from an enhanced understanding of ocean circulation. TTO should improve our estimates of ocean heat flux. For example, we should learn more about whether or not a two-gyre circulatory system exists in the western North Atlantic, about the role of the western boundary undercurrent in exchanging water with the Sargasso Sea, and about the heat and mass interchanges between the North Atlantic and the atmosphere. TTO is not being proposed as an activity within the climate research program. It does, however, hold promise as ancillary research. As WOCE plans are developed, it may be evident that chemical tracers are an essential tool for understanding ocean circulation. TTO and WOCE should be coordinated, and NSF should be aware of the added climate research benefits when evaluating the TTO proposals. Long Lines is the name given to an informal proposed program of hydrographic station sections. Not enough is known of the distribution of temperature, salinity, and density in many areas of the ocean. We are unable to describe the large-scale circulation. We are particularly weak in meridional (i.e., north-south) sections that would allow us to describe the subsurface zonal (i.e., east-west) circulation. Our ignorance may even lead our models astray, since most existing sections are zonal. Even a few meridional sections, if well located, might resolve some questions of ocean circulation: Does the Gulf Stream extend east of the Mid-Atlantic Ridge? Does the Gulf Stream recirculation begin in the eastern North Atlantic? What circulation produces the observed tongue of salty Mediterranean water that extends westward into the North Atlantic? We do not now have answers to these questions even though they concern the North Atlantic, the ocean we know most about. The sections that have been suggested for Long Lines are more numerous in the Southern Hemisphere than in the Northern Hemisphere; there are fewer existing data there. If a Long Lines program is begun, it will contribute to our fundamental knowledge of the large-scale physical oceanography of the world ocean. NSF probably will want to evaluate proposals on this basis. However, the program also
47 could have an important benefit to our understanding the role of the oceanic general circulation in climate variability. Judged solely on the criteria of contributions to the climate research program, Long Lines might not have high priority. If, however, it is judged to be important to our knowledge of the physical structure and circulation of the ocean, the additional benefit to the climate research program should be weighed in assigning priorities. WORKING WITH OTHER COUNTRIES Ocean climate research activities of other countries have the potential of adding to the American effort. In some cases, cooperative work with other countries can produce benefits to the United States that are greater than the incremental expense. French programs in the Atlantic and the Indian oceans have already been mentioned. Other countries are active in ocean research programs that augment or could augment American efforts. A comprehensive catalog of these is beyond the scope of this report, but a few examples may serve to indicate what is possible. Japan has carried out regular ocean surveys for many decades. They have developed a number of products and services based on these surveys. Temperature, salinity, and velocity fields within about 500 km of the Japanese coast are routinely mapped. Meridional sections along 137°E and 155°E have been collected twice each year for the past decade. This series may be of value in estimating interannual ocean heat transport in the western Pacific. Japan has the capability for first-rate ocean measurements. Two programs, the Ocean Heat Transport Experiment (OHTEX) and the Ocean Mixed Layer Experiment (OMLET), are being planned as contributions to the climate research program. American programs in the Pacific will benefit from collaboration with them. The Soviet Union has been pushing for more than a decade for a program to make repeated oceanographic observations at fixed locations or sections. Though the rationale for their proposals has changed over the years, the substance has remained the same. As part of the climate research program, they propose a program known as the "Energetically Active Zones of the Ocean" (EAZO), also known under its older name of "Sections." The Sections program has a number of attractive features: among them, four-times-a-year observations of
48 dynamically active regions of the ocean. The Soviet Union has a research vessel capability that is enormous by the standards of any other country. Two of their locations ("polygons") are located off North America, in the Gulf Stream and off Newfoundland. It would thus seem to be to our advantage to cooperate with them. Oceanographers in many countries have been reluctant to endorse the Soviet proposals. There are a number of reasons for this. Soviet oceanographers have a reputation for poor quality control of their data. In particular, their measurements of salinity and currents have often proved too poor for use. Western scientists find that working with Soviet colleagues is difficult because of their inability or unwillingness to communicate. Finally, there is widespread skepticism about Soviet motives. At the moment, the EAZO program is carried as a "national program" within the climate research program (COCO, 1983). If the Soviet Union were to show that it can collect reliable data at regular intervals, the attitude of American oceanographers would likely change. If that should happen, it could be to the advantage of the United States to work with the USSR. The Federal Republic of Germany, the United Kingdom, and Canada are active in the North Atlantic. U.S. scientists generally find it easy to work with scientists from these countries, and there is consequently little formal intergovernmental structure. Cooperative climate programs with these and other countries should not be overlooked, however, since the benefits of working with competent scientists from these countries are great.
