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Un registro de 0,5 millones de años de variabilidad climática a escala milenaria en el Atlántico Norte
1Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA. Salem State College, Salem, MA 01970, USA.
Science (New York, N.Y.)
|February 12, 1999
Resumen
Los registros de sedimentos marinos revelan que la inestabilidad climática del Atlántico Norte se amplifica cuando las capas de hielo superan un umbral de tamaño crítico. Esto conduce a mayores fluctuaciones de temperatura de la superficie del mar y al aumento de la descarga de icebergs durante los períodos glaciales.
Área de la Ciencia:
- Paleoclimatología Paleoclimatología
- Oceanografía La oceanografía es la oceanografía.
- Glaciología glaciología.
Sus antecedentes:
- Los registros de sedimentos marinos del Atlántico Norte subpolar proporcionan información sobre las dinámicas climáticas del pasado.
- La variabilidad climática a escala milenaria ha sido una característica de la región del Atlántico Norte durante los últimos 0,5 millones de años.
- El tamaño de las capas de hielo juega un papel crucial en la modulación de la inestabilidad climática regional.
Objetivo del estudio:
- Para investigar la relación entre el tamaño de la capa de hielo y la inestabilidad climática regional.
- Identificar los umbrales críticos en el crecimiento de las capas de hielo que desencadenan una mayor variabilidad climática.
- Para analizar los cambios en la temperatura de la superficie del mar y los patrones de descarga de icebergs.
Principales métodos:
- Análisis de núcleos de sedimentos marinos largos y continuos del Atlántico Norte subpolar.
- Examen de los valores del isótopo de oxígeno bentónico (delta18O) para indicar el tamaño de la capa de hielo.
- Evaluación de los indicadores para la descarga de icebergs y las fluctuaciones de temperatura de la superficie del mar.
Principales resultados:
- Se identificó un umbral crítico para el tamaño de la capa de hielo, indicado por un valor de delta18O de 3.5 por mil.
- Más allá de este umbral, la variabilidad a escala milenaria en la temperatura de la superficie del mar y la descarga de icebergs aumentó significativamente.
- Las oscilaciones de la temperatura de la superficie del mar se amplifican de 1-2°C a 4-6°C, con frecuentes descargas de grandes icebergs.
Conclusiones:
- El tamaño de la capa de hielo es un factor clave para amplificar la variabilidad climática a escala milenaria en el Atlántico Norte.
- El umbral de inestabilidad identificado se alcanza con cambios relativamente menores de las configuraciones modernas de la capa de hielo.
- El interglacial del Holoceno representa un estado climático estable fuera del rango de inestabilidad amplificada observada durante los glaciales.
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