Executive Summary
The National Research Council's (NRC's) study on the Global Ocean—Atmosphere—Land System (GOALS) began in 1995 with the establishment of the GOALS Panel, which was tasked by the Climate Research Committee (CRC) to recommend a strategy for U.S. participation in the international GOALS/Climate Variability and Predictability (CLIVAR) programme.
Specifically, under the oversight of the Board on Atmospheric Sciences and Climate (BASC), through its CRC, the panel was charged to:
- Encourage the initiation of a U.S. GOALS Project Office and provide overall scientific leadership and regular guidance on long-range scientific policy, planning, progress, and priorities to that office as well as to involved agencies on behalf of the CRC.
- Report regularly to inform the CRC on the Panel's involvement in U.S. GOALS plans and activities and to receive guidance from the CRC on GOALS matters in the context of the overall U.S. climate research program.
- Advise on U.S. participation and provide U.S. inputs to the international GOALS program planning.
The current document follows directly from the panel's charge. The principal purpose of the document is to provide a strategy for U.S. participation in GOALS/CLIVAR, which should endure for the 15-year duration of the program. At the same time, it is realized that during a program of such length, an evolution of emphases and priorities will occur with advances of knowledge and new
discoveries. This document emphasizes explicit and necessary first steps and initial priorities.
The scientific objectives of GOALS are described in the GOALS Scientific Plan (NRC, 1994a) and summarized in Section 2 of this report. A key aspect of GOALS is the identification of those characteristics of the global system that would make significant improvements in climate prediction on seasonal-to-interannual time scales possible.
The impetus for GOALS stemmed from the success of TOGA, the Tropical Oceans and Global Atmosphere program, which established the existence of ''predictability'' on seasonal-to-interannual time scales in the Pacific Ocean for equatorial sea surface temperature (SST) and for precipitation around the tropical Pacific and in some regions far removed. Much of this predictability is attributed to ocean—atmosphere coupled processes in the Pacific Ocean basin. More exhaustive research is considered necessary to explore the possibility of recognizable interactive processes occurring within or between other components of the Earth system. For example, empirical studies have hinted that anomalous monsoon seasons are foreshadowed by coherent and robust signals in remote locations. Though not fully investigated, linkages are also apparent between the monsoons and El Niño/Southern Oscillation (ENSO), Eurasian snow cover, and other climate system components. If "climate memory" exists in the higher-latitude systems, it is hypothesized to be in the ocean, sea-ice, and hydrological and ground surface processes over the continents.
A fundamental objective of GOALS is to extend the domains of interest outwards from the tropical Pacific basin, the region of primary attention during TOGA. A compelling reason for this expanded domain is the need to understand and quantify the effect of fluctuations in other major heat sources and sinks of the tropics and subtropics on the global general circulation and thereby improve predictions of weather and climate in both local and remote regions—including those in higher latitudes. Thus, the GOALS Panel proposes extending the study of ocean—atmosphere interaction on seasonal-to-interannual time scales to the three tropical oceans. To this end, three initial regional observational foci have been identified in Section 3: (1) the tropical Pacific Ocean, (2) the Americas and surrounding oceans, and (3) the Indian Ocean and land masses that surround it. In addition to these regional foci and their remote influences on higher latitudes, the panel recommends that GOALS investigate predictability inherent to the extratropics, as well as the interaction between land-surface hydrological processes and the atmosphere at all latitudes.
The global extent of the program poses a considerable research and observational challenge. Section 6 details the observational component, which will require the full utilization of all available (and planned) resources in order to achieve global coverage of key climate variables. In this regard, it is emphasized that although significant and increasing problems exist in monitoring the atmosphere, far greater problems exist in monitoring the ocean. The necessity for
continuous global observations of the ocean, land, ice, and atmosphere underscores the importance of a comprehensive satellite program for GOALS, in conjunction with in situ measurements. The key observational variables identified by the panel are also detailed in Section 6. Section 7 recommends a philosophy for the establishment of special process studies aimed at elucidating specific physical processes important for seasonal-to-interannual prediction. The observations to be made within the GOALS program also underpin empirical and diagnostic studies (Section 8) and provide the data for the initialization and evaluation of models. The program's modeling component, described in Section 9, is hierarchical and inherently global even though the development and use of "embedded" high-resolution models are also envisaged, particularly for the prediction of regional and local climate variability and its impacts on society, industry, and natural resources.
The GOALS Panel assigns very high priority to the maintenance and enhancement of the TOGA atmospheric and oceanic observing systems and continued investigation of ENSO, implemented under TOGA. Equal priority is assigned to the study of atmosphere—ocean—land interaction in the Americas and efforts to improve the understanding and prediction of the North and South American monsoon systems. This latter effort has been codified through the U.S. Pan American Climate Studies (PACS) program and with international partners as the Variability of the American Monsoon Systems (VAMOS) program. Next in order of priority is the study of the Asian—Australian monsoon system. The Asian—Australian monsoon system undergoes significant interannual variability, whose impact is important to a large proportion of the population of the planet and the global climate system. To ensure a meaningful scientific investigation of this component of GOALS, the panel recommends that the United States seek international partners for the exploration of the Asian—Australian monsoon system. Just as the maintenance of the Pacific ocean—atmosphere observational array and the PACS program are expected to require strong interagency support in the United States, the global and far reaching totality of GOALS would require a well-coordinated international effort. To this end, the GOALS Panel should work closely with the International CLIVAR Scientific Steering Group of the World Climate Research Programme (WCRP).
Furthermore, the GOALS Panel recognizes that achieving the scientific objectives of GOALS requires that significant attention be paid to events and phenomena of both shorter and longer time scales (i.e., time scales outside the seasonal-to-interannual range). Thus, ocean—atmosphere—land interactions on intraseasonal (weeks to months) time scales are considered important and worthy of serious investigation. Correspondingly, the interdecadal modulation of the interannual variability of the coupled system also needs to be clearly understood. To address these concerns the panel proposes that the scientific development and implementation of GOALS should be closely coordinated with the Global Energy and Water Cycle Experiment (GEWEX) and the Climate Variability on Decade-
to-Century Time Scales (DecCen) programs, thereby contributing to a cohesive and overarching structure consistent with the objectives of the U.S. Global Change Research Program (USGCRP) and international CLIVAR.
The prospect of predicting seasonal-to-interannual variations in different parts of the world brings with it considerable opportunities to benefit climate-sensitive social and economic activities such as those involved in the planning and management of agriculture, water, fisheries, energy, natural resources, public health, and tourism, among others. The panel believes strongly in the concept of an "integrated" prediction system that includes the physical and social sciences as active partners (Section 10). To this end, the panel places high priority on the establishment of an ongoing dialogue between the physical scientists who make climate observations and predictions, and the user community. This dialogue is likely to be most beneficial if commenced very early in the development of GOALS.
Data management is viewed as an overarching activity that cuts across all the other elements of GOALS (Section 11). Internal linkages described in Section 12 refer to possible implementation aspects comprising a combination of individual research investigators and consortia, the precise funding details of which should be determined by the federal agencies responsible for and involved in GOALS. The interactions necessary between GOALS and other national and international research and observational programs are also summarized in Section 12, as are other coordination mechanisms and implementation aspects.
To further develop more specific plans for the implementation of GOALS, the panel proposes the establishment of working groups on observations and modeling, in addition to the creation of a GOALS Project Office, and a coordinated interagency federal mechanism to which the panel could be a scientific advisory body.
