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Rastrear el origen y el destino de los NOx en la atmósfera ártica utilizando isótopos estables en nitrato

Samuel Morin¹, Joël Savarino, Markus M Frey

¹CNRS, Institut National des Sciences de l'Univers, France. samuel.morin@ujf-grenoble.fr

Science (New York, N.Y.)

|November 1, 2008

Resumen

El nitrato atmosférico del Ártico se origina en las emisiones de la capa de nieve en primavera. El óxido de bromo oxida localmente los óxidos de nitrógeno (NOx), lo que afecta significativamente el presupuesto de nitratos y la química atmosférica.

Área de la Ciencia:

Química atmosférica La química atmosférica es la química de la atmósfera.
La geoquímica de los isótopos es una geoquímica de isótopos.
Ciencias ambientales del Ártico Ciencias ambientales del Ártico

Sus antecedentes:

Los óxidos de nitrógeno (NOx) son cruciales para el ciclo reactivo del nitrógeno y la capacidad oxidativa atmosférica.
La deposición de nitratos es un componente clave del ciclo reactivo del nitrógeno.
Comprender las fuentes y transformaciones de NOx y nitratos es vital para los estudios atmosféricos.

Objetivo del estudio:

Investigar el origen estacional y el destino de los óxidos de nitrógeno (NOx) y nitratos atmosféricos en el Ártico.
Para utilizar proporciones estables de isótopos de nitrógeno y oxígeno en nitrato para la atribución de la fuente.
Para limitar el papel de los oxidantes atmosféricos en la formación de nitratos.

Principales métodos:

Recopilación y análisis de muestras de nitrato de la atmósfera ártica.
Medición de las relaciones de isótopos estables de nitrógeno y oxígeno (15N/14N y 18O/16O) en nitrato.
Aplicación del análisis isotópico para inferir fuentes de NOx y nitratos y vías de transformación.

Principales resultados:

En primavera, las emisiones fotoquímicas de nitrógeno reactivo de la capa de nieve contribuyen significativamente al NOx atmosférico.
La oxidación local de NOx por el óxido de bromo surge como una de las principales vías para la formación de nitratos en la primavera ártica.
La composición isotópica del nitrato proporciona restricciones sólidas sobre la importancia relativa de los oxidantes atmosféricos.

Conclusiones:

El estudio aclara las vías dominantes para la formación de nitratos en la atmósfera ártica, particularmente durante la primavera.
La oxidación mediada por óxido de bromo de NOx se identifica como un proceso clave que influye en el presupuesto de nitrato del Ártico.
El análisis isotópico de nitrato ofrece una poderosa herramienta para reconstruir las condiciones atmosféricas pasadas y los regímenes oxidantes.

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