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The Tropical Ocean-Global Atmosphere observing system: A decade of progress

Michael J. McPhaden,1 Antonio J. Busalacchi,2 Robert Cheney,3 Jean-René Donguy,4 Kenneth S. Gage,5 David Halpern,6 Ming Ji,7 Paul Julian,8 Gary Meyers,9 Gary T. Mitchum,10 Pearn P. Niiler,11 Joel Picaut,12,13 Richard W. Reynolds,7 Neville Smith,14 and Kensuke Takeuchi15

1Pacific Marine Environmental Laboratory, NOAA, Seattle, Washington
2NASA Goddard Space Flight Center, Greenbelt, Maryland
3National Ocean Service, NOAA, Silver Spring, Maryland
4Institut Français de Recherche Scientifique pour le Développement en Coopération, Plouzane, France
5Aeronomy Laboratory, NOAA, Boulder, Colorado
6Jet Propulsion Laboratory, California Institute of Technology, Pasadena
7National Centers for Environmental Prediction, NOAA, Camp Springs, Maryland
8Suitland, Maryland
9Commonwealth Scientific and Industrial Research Organization, Tasmania, Australia
10Department of Marine Science, University of South Florida, Saint Petersburg
11Scripps Institution of Oceanography, La Jolla, California
12Institut Français de Recherche Scientifique pour le Développement on Coopération
13Now at NASA Goddard Space Flight Center, Greenbelt, Maryland
14Bureau of Meteorology Research Centre, Melbourne, Victoria, Australia
15Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan

Journal of Geophysical Research, 103(C7), 14,169-14,240 (1998).
Copyright ©1998 by the American Geophysical Union. Further electronic distribution is not allowed.


A major accomplishment of the recently completed Tropical Ocean-Global Atmosphere (TOGA) Program was the development of an ocean observing system to support seasonal-to-interannual climate studies. This paper reviews the scientific motivations for the development of that observing system, the technological advances that made it possible, and the scientific advances that resulted from the availability of a significantly expanded observational database. A primary phenomenological focus of TOGA was interannual variability of the coupled ocean-atmosphere system associated with El Niño and the Southern Oscillation (ENSO). Prior to the start of TOGA, our understanding of the physical processes responsible for the ENSO cycle was limited, our ability to monitor variability in the tropical oceans was primitive, and the capability to predict ENSO was nonexistent. TOGA therefore initiated and/or supported efforts to provide real-time measurements of the following key oceanographic variables: surface winds, sea surface temperature, subsurface temperature, sea level and ocean velocity. Specific in situ observational programs developed to provide these data sets included the Tropical Atmosphere-Ocean (TAO) array of moored buoys in the Pacific, a surface drifting buoy program, an island and coastal tide gauge network, and a volunteer observing ship network of expendable bathythermograph measurements. Complementing these in situ efforts were satellite missions which provided near-global coverage of surface winds, sea surface temperature, and sea level. These new TOGA data sets led to fundamental progress in our understanding of the physical processes responsible for ENSO and to the development of coupled ocean-atmosphere models for ENSO prediction.

And thorough this distemperature we see the seasons alter...

Shakespeare's "A Midsummer Night's Dream"
Act 2, Scene 1

1. Introduction
2. An Overview of the TOGA Observing System
2.1 El Niņo: A Primary Focus of TOGA
2.2 Key Variables and Sampling Requirements
2.3 TOGA Observing System Components
3. Scientific Progress: Improved Description and Understanding
3.1 Long-Term Mand and Mean Seasonal Cycle
3.2 ENSO Variability
3.3 Intraseasonal Kelvin Waves
3.4 Local Response to Westerly Wind Burst Forcing
3.5 Instability Waves
3.6 ENSO and the Indo-Pacific Throughflow
3.7 ENSO and Global Oceanic Variability
3.8 Salinity Variations
3.9 Atmospheric Variability
3.10 Relation to Process-Oriented Studies
4. Role of the TOGA Observing System in the Development of Improved Model-Based Analyses and Predicted Products
4.1 Introduction
4.2 Improved Wind Analyses for Use in Modeling Studies
4.3 Assimilation of Temperature Data Into Ocean Models
4.4 Initialization of Coupled Ocean-Atmosphere Models for Climate Forecasting
5. Discussion and Conclusion
Appendix A: A Rude Awakening
Appendix B: In Situ Oceanographic Components of the Observing System-Technical and Historical Background
B1. Tropical Atmosphere Ocean (TAO) Array
B2. Drifters
B3. TOGA Tide Gauge Network
B4. Volunteer Observing Ship (VOS) Network
Appendix C: Satellite Components of the Observing System-Technical and Historical Background
C1. AVHRR and Blended Sea Surface Temperature Analyses
C2. Satellite Altimetry
C3. Satellite Surface Winds
Appendix D: In Situ Meteorological Components of the Observing System-Technical and Historical Background
D1. TOGA Upper Air Network
D2. Island Wind Profilers

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