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Sincronicidad de las temperaturas tropicales y de altas latitudes del Atlántico durante la última terminación glacial
David W Lea1, Dorothy K Pak, Larry C Peterson
1Department of Geological Sciences and Marine Science Institute, University of California, Santa Barbara, CA 93106, USA. lea@geol.ucsb.edu
Science (New York, N.Y.)
|September 6, 2003
Resumen
Las temperaturas de la superficie del mar del Atlántico tropical (SST) siguieron de cerca los cambios de Groenlandia y el metano atmosférico durante la última terminación glacial. El Dryas más joven vio una caída significativa de la SST, vinculada a cambios en la zona de convergencia intertropical.
Área de la Ciencia:
- Paleoceanografía y paleoclimatología.
- La geoquímica marina es la geoquímica marina.
- La dinámica del clima La dinámica del clima La dinámica del clima
Sus antecedentes:
- Comprender la variabilidad climática pasada y la sincronicidad entre las regiones tropicales y de latitudes altas es crucial para predecir el cambio climático futuro.
- La cuenca de Cariaco proporciona un valioso archivo para reconstruir las temperaturas pasadas de la superficie del mar (SST) debido a su entorno deposicional único.
- La última terminación glacial y el evento Younger Dryas representan períodos críticos de rápido cambio climático.
Objetivo del estudio:
- Para generar un registro de temperatura de la superficie del mar (SST) de alta resolución desde el Atlántico tropical occidental durante la última terminación glacial.
- Para comparar la sincronización de los cambios de SST tropicales con proxies climáticos de altas latitudes y concentraciones de metano atmosférico.
- Investigar los mecanismos que impulsan los cambios climáticos sincrónicos entre los trópicos y las latitudes altas.
Principales métodos:
- Análisis de las relaciones Mg/Ca en foraminíferos planctónicos de núcleos de sedimentos de la cuenca de Cariaco.
- Desarrollo de un registro proxy de temperatura de la superficie del mar (SST) de alta resolución.
- Correlación del registro del SST con los registros existentes de temperatura del aire y de metano atmosférico del Proyecto 2 de la capa de hielo de Groenlandia.
Principales resultados:
- Los cambios del SST del Atlántico tropical durante la última terminación glacial fueron sincrónicos con las temperaturas del aire de Groenlandia y el metano atmosférico, dentro de +/-30 a +/-90 años.
- Un evento de enfriamiento prominente de 3-4 ° C en SSTs tropicales ocurrió durante el intervalo Younger Dryas.
- La sincronización de estos eventos deglaciales sugiere un rápido desplazamiento hacia el sur de la zona de convergencia intertropical (ZCIT).
Conclusiones:
- Las SST tropicales del Atlántico respondieron rápida y sincrónicamente a los principales cambios climáticos durante la última terminación glacial, incluido el Younger Dryas.
- Un desplazamiento hacia el sur de la ITCZ es un mecanismo plausible que vincula la temperatura tropical, el metano atmosférico y los cambios climáticos de altas latitudes.
- Este estudio pone de relieve la interconexión del sistema climático de la Tierra durante los períodos de rápida deglaciación.
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