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Frente de hielo bloqueando el transporte de calor del océano a una plataforma de hielo antártica
A K Wåhlin1, N Steiger2,3, E Darelius2,3
1Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden. awahlin@gu.se.
Nature
|February 28, 2020
Resumen
Las plataformas de hielo antárticas se están derritiendo debido al aumento del calor del océano. Un frente de hielo con forma de escalón bloquea el flujo de calor, limitando la fusión y la pérdida de hielo. Este hallazgo es crucial para los modelos climáticos.
Área de la Ciencia:
- La oceanografía
- Glaciología
- Ciencias del clima
Sus antecedentes:
- La pérdida de masa de la capa de hielo antártica se está acelerando.
- El aumento de la fusión basal de las plataformas de hielo impulsa este cambio.
- El transporte de calor del océano a la plataforma continental es un foco clave.
Objetivo del estudio:
- Investigar los controles en el transporte de calor del océano a las plataformas de hielo de la Antártida.
- Determinar por qué el flujo de calor hacia la costa supera las tasas de fusión observadas.
- Comprender el papel de la topografía del frente de hielo en la regulación del flujo de calor.
Principales métodos:
- Observaciones directas desde la plataforma de hielo de Getz.
- Experimentos de laboratorio en una plataforma giratoria.
- Análisis de los componentes del flujo de calor (barotrópico y baroclínico).
Principales resultados:
- El frente de hielo en forma de escalón bloquea el flujo de calor (barotrópico) independiente de la profundidad.
- Solo el componente térmico más pequeño, de profundidad variable (baroclínico), entra en la cavidad subglacial.
- Este mecanismo de bloqueo explica las discrepancias entre el flujo de calor y las tasas de fusión.
Conclusiones:
- La topografía del frente de hielo es un control crítico sobre el calor del océano que entra en las cavidades de la plataforma de hielo.
- La representación precisa de la topografía del paso frontal del hielo en los modelos es esencial para simular las tasas de fusión.
- Este hallazgo puede explicar por qué los cambios en la densidad de la columna de agua indican mejor la variabilidad de la fusión que el transporte de calor de la plataforma.
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