It should be clear that one cannot sample the entire large, four dimensional California Current, with its many habitats and species, with sufficient resolution to determine its internal response to external forcing at very many points in time and space. The challenge is to design and implement a research program that takes advantage of existing temporal and spatial variability to isolate mechanisms that determine how populations in the CCS respond to climate variability. To facilitate the efficient implementation of this plan, we will follow one of two courses: each AO should contain a detailed statement of research topics for which research proposals are sought. Alternatively, U.S. GLOBEC will release under separate cover an Implementation Plan for each proposal solicitation. We recommend the first AO be released as soon as September/October 1994.
We also note that the Coastal Ocean Processes (CoOP) Program is planning a study of wind-driven transport processes on the U.S. west coast before the end of the decade. The central motivating question of their study is: "What processes control the cross-margin transport of biological, chemical and geological materials in a strongly wind-driven system?" They plan to support modeling studies and 1-2 years of interdisciplinary process-oriented field research. Specifics of the program have not been fully defined-but there are ongoing efforts within the steering committees of CoOP and U.S. GLOBEC to ensure that the two programs complement each other in the most complete manner possible. The general questions identified by CoOP as important in this region are: (1) How do ocean-atmosphere feedbacks act to structure the system? (2) How and where do chemical species enter and leave the euphotic zone from the interior and near-bottom regions? (3) How are plankton distribution patterns over the continental margin maintained? and (4) How do exchange processes between the active sediment layer and the water affect the distribution and fate of biologically, chemically and geologically important materials? Although it does not identify specific sites where field work would be done, the CoOP Science Plan (in its Draft form) suggests that much could be learned from a comparison between a wind-driven flow over a strongly frontal region (with a front over the shelf, as off central Oregon) and less-frontal region (where a front may be found much farther offshore, as off northern/central California). These two areas lie within the regions defined by U.S. GLOBEC as Regions I and II. Thus, the two programs have mutual interests in similar scientific questions (especially processes that affect the transport of benthic invertebrate larvae and maintain planktonic populations nearshore) and in the regions where field work could be designed to answer these questions (Regions I and II, in the U.S. GLOBEC plan). In addition, CoOP is very interested in nutrient and phytoplankton dynamics, which would be a valuable addition to the information collected by U.S. GLOBEC.
U.S. GLOBEC recommends that the activities discussed below be considered as part of an initial Announcement of Opportunity:
(1) Compilation and analysis of a physical oceanography-plankton-fisheries database of historical measurements in the CCS, as a function of latitude. This will serve to define better the regional differences in forcing and response within the CCS, and the extent to which long term changes are regionally focused or coherent throughout the CCS. Existing satellite data archives also need further analysis, including comparisons of the CCS to other EBCs, in order to extend the observed range of forcing and response.
Examples of data that need further analysis include existing coastal meteorology, sea surface temperature, salinity and sea-level, merchant ship records, paleoecological data from sediments in anoxic basins, the CalCOFI data, fisheries landings data, and data in hydrographic and current meter archives. Most of the data are not widely available to the academic or government scientists, and few of the data sets have been cross-indexed and examined in a multidisciplinary, hypothesis-testing mode. Relatively little effort has been given to examining them in the context of climate variability, or in terms of regional or among EBC comparisons. Moreover, numerous biological samples remain uncounted in jars in various archives at oceanographic centers along the U.S. West coast. We believe a first step in a U.S. GLOBEC CCS program should be an examination of data sets and samples that have been collected to date from the CCS. These will ultimately be of immense value in attempting to describe changes, whether they be long-term and gradual or abrupt, in the CCS ecosystem. Satellite data, available over a relatively shorter time scale (2-14 years), should also be analyzed to determine regional differences in mesoscale features and movement of transition zones. This analysis will be useful in prescribing field sampling locations and strategy. Comparative studies of other EBCs could also provide useful information as to experimental design, by providing hypotheses on the direction that certain changes might take either due to ENSO or climate change variability.
(2) Modeling studies should be started now to develop and validate the biophysical models, and to explore the sensitivity of coupled physical-biological models to flow fields and to biological processes of growth, fecundity and mortality. The modeling component of the program should determine likely environmental conditions under different climate change scenarios and attempt to link GCM and regional-scale models, and couple physical and biological parameters in regional models. Model studies of biological rates and responses to physical conditions should begin as soon as possible. Output from these models will be useful in establishing sampling sites along the coast, and in suggesting how present latitudinal differences may be applied toward forecasting the consequences of climate change.
(3) Augmentation of existing monitoring programs, or the initiation of new monitoring programs, at different locations in the CCS should begin as soon as possible. This activity will provide a measure of interannual variability, especially as related to ENSO. Ongoing monitoring allows one to place intensive field process experiments in a temporal context. Concurrent coordinated monitoring programs at different localities should utilize comparable measurement methods. To the extent possible, this monitoring should include real-time reporting of the data, allowing a fast response to ENSO or other unusual events.