Browsing by Author "Enfield, D"

Now showing 1 - 3 of 3
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    Relaciones entre el inicio y el término de la estación lluviosa en Centroamérica y los Océanos Pacífico y Atlántico Tropical
    (Investigaciones Marinas, 1998) Alfaro, E; Cid, L; Enfield, D
    En los últimos años diversos estudios han mostrado que las anomalías en los campos de temperaturas de los océanos Pacífico y Atlántico Tropical están relacionadas con variaciones, tanto en la intensidad como en la duración de la estación lluviosa sobre Centroamérica. En este trabajo se usaron, como variables independientes, distintos índices oceanográficos y atmosféricos, principalmente de las distribuciones de la temperatura superficial del mar (TSM) en los océanos Pacífico y Atlántico Tropical, para explicar las variaciones en las fechas de inicio (IELL) y término (TELL) de estación lluviosa sobre la región centroamericana. El índice del Atlántico Norte (ATN) y los índices IOS-Niño3 mostraron las mayores correlaciones con el IELL y el TELL, respectivamente.
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    The dependence of caribbean rainfall on the interaction of the tropical Atlantic and Pacific Oceans
    (Journal of Climate, 1999) Enfield, D; Alfaro, E
    Seasonally stratified analyses of rainfall anomalies over the intra-Americas sea and surrounding land areas and of onset and end dates of the Central American rainy season show that the variability of the tropical Atlantic sea surface temperature anomaly (SSTA) is more strongly associated with rainfall over the Caribbean and Central America than is tropical eastern Pacific SSTA. Seasonal differences include the importance of antisymmetric configurations of tropical Atlantic SSTA in the dry season but not in the rainy season. Both oceans are related to rainfall, but the strength of the rainfall response appears to depend on how SSTA in the tropical Atlantic and eastern Pacific combine. The strongest response occurs when the tropical Atlantic is in the configuration of a meridional dipole (antisymmetric across the ITCZ) and the eastern tropical Pacific is of opposite sign to the tropical North Atlantic. When the tropical North Atlantic and tropical Pacific are of the same sign, the rainfall response is weaker. The rainy season in lower Central America tends to start early and end late in years that begin with warm SSTs in the tropical North Atlantic, and the end dates are also delayed when the eastern equatorial Pacific is cool. This enhancement of date departures for zonally antisymmetric configurations of SSTA between the North Atlantic and Pacific is qualitatively consistent with the results for rainfall anomalies.
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    The rainy season in Central America: An initial success in prediction
    (IAI Newsletters, 1999) Alfaro, E; Enfield, D
    Based on the results of research funded under an IAI grant (ISP-1), a successful climate outlook was issued in early March, 1999, for the 1999 rainy season (May-November) in lower Central America. Press releases authored by the Centro de Investigaciones Geofisicas of the Universidad de Costa Rica (CIGEFI/UCR) were published on 03/March/99, 05/March/99 and 10/March/99 (e.g. Lizano and Alfaro, 1999) in the university weekly Semanario Universidad and in the daily newspaper La Prensa Libre, which also were aired on a Costa Rican TV program (UCR Channel 15) on 10/March/99. The outlook, based on the evolution of sea surface temperature (SST) indices for the tropical North Atlantic and East Pacific, advised the Costa Rican media. It then motivated a more in-depth study by the Instituto Meteorologico Nacional de Costa Rica (IMN-CR). In the IMN-CR's March bulletin, they issued a similar forecast, which subsequently proved successful.