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El papel de la temperatura de la superficie del mar y la retroalimentación de la humedad del suelo en la sequía de
1National Centers for Environmental Prediction, Camps Springs, Maryland 20746, USA.
Nature
|December 29, 2000
Resumen
La sequía de Oklahoma-Texas de 1998 fue impulsada por anomalías de la temperatura de la superficie del mar y la circulación atmosférica. Las retroalimentaciones regionales, como la reducción de la evaporación, mantuvieron la sequía hasta que intervinieron sistemas climáticos más grandes.
Área de la Ciencia:
- Climatología y climatología.
- Ciencias de la atmósfera Ciencias atmosféricas.
- Meteorología Meteorología.
Sus antecedentes:
- La sequía de Oklahoma-Texas de 1998 alcanzó niveles de "cuenco de polvo", a pesar de las predicciones exitosas de El Niño en otros lugares.
- Las respuestas atmosféricas extratropicales a las anomalías de temperatura de la superficie del mar son menos predecibles que las respuestas tropicales.
Objetivo del estudio:
- Para investigar los orígenes y la persistencia del clima extremo extratropical de Oklahoma-Texas de 1998.
- Diferenciar las funciones de las teleconexiones globales y las retroalimentaciones regionales en el desarrollo de la sequía.
Principales métodos:
- Experimentos mecanicistas utilizando modelos atmosféricos globales y regionales.
- Aislamiento de los mecanismos regionales de retroalimentación climática.
Principales resultados:
- Las anomalías de la temperatura de la superficie del mar y la circulación atmosférica favorable iniciaron la sequía en abril-mayo de 1998.
- La reducción de la evaporación y la precipitación creó un bucle de retroalimentación positiva, manteniendo la sequía de junio a agosto.
- La sequía concluyó en el otoño a medida que los sistemas climáticos más fuertes superaron las retroalimentaciones regionales de humedad del suelo.
Conclusiones:
- Las anomalías de la temperatura de la superficie del mar y los patrones atmosféricos son los principales impulsores de las sequías extratropicas.
- Las retroalimentaciones regionales tierra-atmósfera contribuyen significativamente a la persistencia de la sequía.
- Los modelos numéricos que incorporan procesos físicos pueden mejorar las predicciones climáticas regionales.
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