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El ciclo de 100.000 años de la Edad de Hielo identificado y encontrado para retrasar la temperatura, el dióxido de
1Department of Earth Sciences, Godwin Laboratory, University of Cambridge, Pembroke Street, Cambridge CB2 3SA, UK. E-mail: njs5@cam. ac.uk.
Science (New York, N.Y.)
|September 16, 2000
Resumen
El ciclo de 100.000 años de la edad de hielo es impulsado por el ciclo global del carbono, no por la dinámica de las capas de hielo. Los cambios en la concentración de dióxido de carbono atmosférico, influenciados por la excentricidad orbital, controlan este ritmo.
Área de la Ciencia:
- Paleoclimatología Paleoclimatología
- La geoquímica es la geoquímica.
- Ciencias del clima Ciencias del clima Ciencias del clima
Sus antecedentes:
- Los isótopos de oxígeno de los sedimentos de aguas profundas (delta 18 O) muestran un ciclo dominante de 100.000 años, tradicionalmente vinculado a las edades de hielo.
- Los registros de delta marina bentónica ((18) O están influenciados tanto por el volumen de hielo como por las variaciones de temperatura de aguas profundas.
Objetivo del estudio:
- Para aislar el componente de volumen de hielo del delta de sedimentos de aguas profundas 18O registro.
- Para investigar los impulsores del ciclo climático de 100.000 años.
Principales métodos:
- Se utilizan registros delta de ajuste orbital de 18O de oxígeno atmosférico en el hielo antártico (Vostok).
- Separadas señales para el volumen de hielo, la temperatura de las aguas profundas y las variaciones del delta atmosférico (efecto Dole).
Principales resultados:
- El volumen de hielo en el período de 100.000 años está por detrás del dióxido de carbono atmosférico, la temperatura del aire de Vostok y la temperatura de las aguas profundas.
- Estas variables están sincronizadas con la excentricidad orbital.
Conclusiones:
- El ciclo climático de 100.000 años no está impulsado principalmente por la dinámica de las capas de hielo.
- La respuesta del ciclo global del carbono a la excentricidad orbital, alterando el CO2 atmosférico, probablemente genera este ritmo.
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