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Evidencia de interglaciales más cálidos en los núcleos de hielo de la Antártida Oriental
L C Sime1, E W Wolff, K I C Oliver
1British Antarctic Survey, Cambridge CB3 0ET, UK. lsim@bas.ac.uk
Nature
|November 20, 2009
Resumen
Los registros de núcleos de hielo antárticos revelan que las temperaturas interglaciales pasadas fueron significativamente más cálidas de lo estimado anteriormente. La relación entre las firmas isotópicas y la temperatura no es lineal, lo que sugiere que las estimaciones anteriores pueden ser demasiado bajas.
Área de la Ciencia:
- Paleoclimatología Paleoclimatología
- Glaciología glaciología.
- Modelado del clima Modelado del clima
Sus antecedentes:
- Los núcleos de hielo antárticos proporcionan datos cruciales sobre las variaciones climáticas pasadas durante más de 800.000 años.
- Las relaciones de isótopos estables (oxígeno e hidrógeno) se utilizan para reconstruir las temperaturas de la Antártida.
- Estudios anteriores asumieron una relación uniforme y constante entre las relaciones isotópicas y la temperatura.
Objetivo del estudio:
- Reevaluar la relación entre las firmas isotópicas y la temperatura en los núcleos de hielo de la Antártida Oriental.
- Investigar la no uniformidad de esta relación en diferentes sitios y períodos climáticos.
- Para refinar las reconstrucciones de temperaturas pasadas, particularmente para los períodos interglaciales.
Principales métodos:
- Análisis de tres registros de núcleos de hielo de la Antártida Oriental de 340 kyr.
- Integración de las simulaciones del Modelo de Circulación General (MGC).
- Comparación de los datos isotópicos con las salidas climáticas modeladas.
Principales resultados:
- La relación entre la temperatura y la firma isotópica varía significativamente entre los sitios de núcleos de hielo de la Antártida Oriental durante los períodos interglaciales más cálidos.
- La composición isotópica en el hielo de la Antártida Oriental muestra una menor sensibilidad a los cambios de temperatura en climas más cálidos.
- Esto indica que las conversiones no lineales son necesarias para reconstrucciones precisas de la temperatura en ciertos sitios.
Conclusiones:
- Es probable que las estimaciones de temperatura anteriores para los períodos interglaciales se subestimen.
- Las temperaturas máximas interglaciales de la Antártida pueden haber sido al menos 6 K más altas que las temperaturas actuales.
- Los hallazgos requieren metodologías revisadas para reconstruir el clima antártico pasado utilizando datos de núcleos de hielo.
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