Abstract. 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 oceanatmosphere system associated with E1 Nifio 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 troi•ical 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 AtmosphereOcean (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

No abstract

An ensemble of twenty four coupled oceanatmosphere models has been compared with respect to their performance in the tropical Paci®c. The coupled models span a large portion of the parameter space and dier in many respects. The intercomparison includes TOGA (Tropical Ocean Global Atmosphere)-type models consisting of high-resolution tropical ocean models and coarse-resolution global atmosphere models, coarse-resolution global coupled models, and a few global coupled models with high resolution in the equatorial region in their ocean components. The performance of the annual mean state, the seasonal cycle and the interannual variability are investigated. The primary quantity analysed is sea surface temperature (SST). Additionally, the evolution of interannual heat content variations in the tropical Paci®c and the relationship between the interannual SST variations in the equatorial Paci®c to¯uctuations in the strength of the Indian summer monsoon are investigated. The results can be summarised as follows: almost all models (even those employing¯ux corrections) still have problems in simulating the SST climatology, although some

NCEP's newly developed second-generation operational seasonal forecast system aims at a seamless suite of forecasts and provides much more comprehensive datasets for users.n April 2000, a new dynamical seasonal prediction system was introduced at the National Centers for Environmental Prediction (NCEP; the acronyms used in this paper are summarized in the appendix). The transition to the new system was hastened by a computer fire in September 1999 and subsequent changeover from a Cray C90 to an IBM-SP computer system. This article will be a reference for people who are using the NCEP numerical seasonal forecast products.The first-generation dynamical seasonal prediction model was based on the notion that the seasonal predictability in the Northern Hemisphere extratropics

No abstract