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La fraccionamiento isotópico del cloro en la estratosfera
J C Laube1, J Kaiser, W T Sturges
1School of Environmental Sciences, University of East Anglia, Norwich NR47TJ, UK. j.laube@uea.ac.uk
Science (New York, N.Y.)
|September 4, 2010
Resumen
Los científicos midieron las diferencias isotópicas en el difluorodiclorometano (CF2Cl2), un compuesto relacionado con el agotamiento del ozono. Las altitudes más altas mostraron mayores diferencias de isótopos, que se correlacionan con los niveles más bajos de CF2Cl2, ofreciendo nuevos conocimientos atmosféricos.
Área de la Ciencia:
- Química de la atmósfera química de la atmósfera
- La geoquímica de los isótopos es la geoquímica de los isótopos.
- Investigación de la capa de ozono Investigación de la capa de ozono.
Sus antecedentes:
- Los compuestos orgánicos clorados contribuyen al agotamiento antropogénico de la capa de ozono estratosférica.
- Comprender el destino atmosférico y las firmas isotópicas de estos compuestos es crucial para la investigación de la capa de ozono.
Objetivo del estudio:
- Para medir y analizar la fraccionamiento de isótopos estratosféricos en el difluorodiclorometano (CF2Cl2).
- Para investigar la relación entre la altitud, las proporciones de mezcla de CF2Cl2 y las proporciones de isótopos de cloro.
- Explorar el potencial de estas mediciones para comprender los procesos atmosféricos.
Principales métodos:
- Se utilizó la espectrometría de masas de relación de isótopos para medir las relaciones 37Cl/35Cl en muestras estratosféricas y troposféricas.
- Análisis de muestras de difluorodiclorometano (CF2Cl2) recolectadas a varias altitudes.
- Análisis de correlación entre las diferencias en las proporciones de isótopos y las proporciones de mezcla de CF2Cl2.
Principales resultados:
- El difluorodiclorometano (CF2Cl2) exhibió la mayor diferencia relativa en la relación de isótopos 37Cl/35Cl jamás registrada para un compuesto natural.
- Se observó una fuerte correlación positiva entre la diferencia de la relación isotópica relativa y el aumento de la altitud.
- Este aumento de la diferencia isotópica estaba estrechamente relacionado con la disminución de la relación de mezcla de CF2Cl2 con la altitud.
Conclusiones:
- La fraccionamiento isotópico estratosférico observado de CF2Cl2 proporciona un nuevo trazador para los procesos atmosféricos.
- La relación altitud-dependiente entre las proporciones de isótopos y las proporciones de mezcla ofrece nuevos conocimientos sobre la química atmosférica y el transporte.
- Esta investigación pone de relieve la importancia de las mediciones isotópicas en la comprensión de las sustancias que agotan la capa de ozono y su comportamiento atmosférico.
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