Tropical Ocean-Global Atmosphere program
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The Tropical Ocean Global Atmosphere program is a component of the World Climate Research Program (WCRP) aimed specifically at the prediction of climate phenomena on time scales of months to years. TOGA emphasizes the tropical oceans and their relationship to the global atmosphere. Underlying TOGA is the premise that the dynamic adjustment of the ocean in the tropics is far more rapid than at higher latitudes. Thus disturbances emanating from the western Pacific Ocean (such as El Nino) may propagate across the basin on time scales of weeks compared to years for corresponding basin-wide propagation at higher latitudes. The significance of shorter dynamic times scales near the equator is that they are similar to those of highly energetic atmospheric modes. This similarity allows the formation of coupled modes between the ocean and the atmosphere.
Scientific Objectives of TOGA
The specific goals and scientific objectives of TOGA are (WCRP, 1985);
- To gain a description of the tropical oceans and the global atmosphere as a time dependent system in order to determine the extent to which the system is predictable on time scales of months to years and to understand the mechanisms and processes underlying its predictability.
- To study the feasibility of modeling the couple ocean-atmosphere system for the purpose of predicting its variation on time scales of months to years; and
- To provide the scientific background for designing an observing and data transmission system for operational predication, if this capability is demonstrated, by coupled ocean-atmosphere models.
In order to achieve the TOGA goals, a strategy of large-scale, long-term monitoring of the upper ocean and the atmosphere, intensive and very specific process-oriented studies, and modeling has been planned (WCRP, 1985) and enacted through a series of national, multinational and international efforts (e.g., NAS, 1986; WCRP, 1986). Modeling activities have been coordinated by TOGA Numerical Experimentation Group (TOGA NEG).