Latitudinal distribution of upper stratospheric ClO as derived from Space Borne Microwave Spectroscopy

Aellig, C. P.; Kämpfer, N.; Rudin, Christoph; Bevilacqua, R. M.; Degenhardt, W.; Hartogh, P.; Jarchow, Christopher; Künzi, K.; Olivero, J. J.; Croskey, C. L.; Waters, J. W.; Michelsen, Hope A.

doi:10.1029/96gl01215

Cited by 15 publications

(9 citation statements)

References 17 publications

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“…In the upper stratosphere, it can comprise close to 20% of Cl TOT . Since the signal‐to‐noise ratio for ClO in ACE‐FTS spectra is usually very low, most of the ClO measurements used in this work are from the submillimeter receiver (SMR) [ Urban et al , 2005] on the Odin satellite [ Murtagh et al , 2002], just as Zander et al [1996] used ClO measurements from the Millimeter‐wave Atmospheric Sounder (MAS) [ Hartmann et al , 1996; Aellig et al , 1996] for the ATMOS chlorine budget. Version 1.2 SMR ClO profiles were obtained for the period of February 2004 to January 2005 inclusive, to match the temporal range of the ACE‐FTS measurements.…”

Section: Ace‐fts Measurements Of Chlorine‐containing Speciesmentioning

confidence: 99%

A global inventory of stratospheric chlorine in 2004

Nassar¹,

Bernath²,

Boone³

et al. 2006

J. Geophys. Res.

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Total chlorine (ClTOT) in the stratosphere has been determined using the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) measurements of HCl, ClONO₂, CH₃Cl, Ccl₄, Ccl₃F (CFC-11), Ccl₂F₂ (CFC-12), CHClF₂ (HCFC-22), Ccl₂FCClF₂ (CFC-113), CH₃CClF₂ (HCFC-142b), COClF, and ClO supplemented by data from several other sources, including both measurements and models. Separate chlorine inventories were carried out in five latitude zones (60°–82°N, 30°–60°N, 30°S–30°N, 30°–60°S, and 60°–82°S), averaging the period of February 2004 to January 2005 inclusive, when possible, to deal with seasonal variations. The effect of diurnal variation was avoided by only using measurements taken at local sunset. Mean stratospheric ClTOT values of 3.65 ppbv were determined for both the northern and southern midlatitudes (with an estimated 1σ accuracy of ±0.13 ppbv and a precision of ±0.09 ppbv), accompanied by a slightly lower value in the tropics and slightly higher values at high latitudes. Stratospheric ClTOT profiles in all five latitude zones are nearly linear with a slight positive slope in ppbv/km. Both the observed slopes and pattern of latitudinal variation can be interpreted as evidence of the beginning of a decline in global stratospheric chlorine, which is qualitatively consistent with the mean stratospheric circulation pattern and time lag necessary for transport

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Section: Ace‐fts Measurements Of Chlorine‐containing Speciesmentioning

confidence: 99%

A global inventory of stratospheric chlorine in 2004

Nassar¹,

Bernath²,

Boone³

et al. 2006

J. Geophys. Res.

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“…Pioneering work in measuring ClO has been performed by Andersen et al [1989] using in situ techniques on an aircraft, and by [ de Zafra et al , 1989] using a ground‐based millimeter wave receiver. Global observations of ClO became possible with the Microwave Limb Sounder (MLS) on board UARS [ Waters et al , 1993] and the Microwave Atmospheric Sounder (MAS) on board of the space shuttle [ Aellig et al , 1996]. More recently the detection of ClO mixing ratios for certain altitude layers has been reported using Fourier transform spectroscopy [ Donovan et al , 1997].…”

Section: Introductionmentioning

confidence: 99%

Ozone depletion and chlorine activation in the Arctic winter 1999/2000 observed in Ny‐Ålesund

et al. 2002

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We present vortex‐averaged calculations of ozone loss rates between late December 1999 and mid‐March 2000 derived from data collected by the Radiometer for Atmospheric Measurements (RAM). The ground‐based microwave radiometer RAM is operated at the Arctic station of the Network for the Detection of Stratospheric Change (NDSC) at Ny‐Ålesund, Spitsbergen (79°N, 12°E). Simultaneous observations of stratospheric ozone and chlorine monoxide (ClO) profiles were performed by the RAM during winter and spring 1999/2000. Ozone was monitored continuously and ClO was observed between late February and early April. Maximum ozone loss rates of 35 ppb/d were obtained in mid‐February and in the beginning of March. The ozone loss accumulated to 41% in a layer with a thickness of approximately 10 km centered at the 475 K isentropic level. Ozone loss estimates are compared to results obtained by other groups and to model calculations showing good agreement when all results are adjusted to the same vertical resolution. Simultaneously, we have observed record ClO mixing ratios in the lower stratosphere with a peak mixing ratio of 1.25 ppb on 1 March, corresponding to the strong chemical ozone loss at the same time. The ClO observations are compared to model calculations indicating that the SLIMCAT model underestimates the amount of chlorine activation at the end of the winter in Ny‐Ålesund, in contrast to the good agreement between modeled and observed ozone loss.

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“…The microwave limb emission technique was also used for the first global measurements of stratospheric ClO, which were provided by the Microwave Limb Sounder on the Upper Atmospheric Research Satellite . Later satellite ClO measurements were provided by the Millimeter-wave Atmospheric Sounder (MAS) on the Space Shuttle (Aellig et al, 1996), MIPAS on Evisat von Clarmann et al, 2009b), the Sub-Millimeter Radiometer (SMR) on the Odin satellite (Urban et al, 2004, the Microwave Limb Sounder on the Aura satellite (Santee et al, 2008a) and the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) on the International Space Station (ISS) (Solomon et al, 2000), and Thule, Greenland . Further ground-based ClO measurements were performed on campaign basis, e.g., at the McMurdo station, Antarctica (de Zafra et al, 1989).…”

Section: Clo Measurements In the Stratospherementioning

confidence: 99%

Chlorine in the stratosphere

Clarmann¹

2013

Atmósfera

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Este artículo reseña varios aspectos de los compuestos clorados presentes en la estratosfera, que incluyen tanto su papel como agentes químicos como su función de trazadores de los procesos dinámicos. En la estratosfera, el cloro reactivo se libera a partir de los clorofluorocarbonos y otros gases orgánicos que contienen cloro. La mayor parte del cloro reactivo se convierte en compuestos inertes que almacenan cloro, como ClONO 2 y HCl. La reactivación del cloro estratosférico ocurre principalmente por reacciones heterogéneas en vórtices polares invernales, en combinación con la luz solar. Los ciclos catalíticos de Cl, ClO, BrO, Cl 2 O 2 , ClO 2 y otros compuestos como NO, NO 2 , OH y HO 2 destruyen el oxígeno impar (ozono y oxígeno atómico) de la atmósfera. El ciclo del dímero de ClO es particularmente importante en la formación del agujero de ozono, mientras que en latitudes medias el HOCl tiene alguna relevancia. También los eventos de protones solares pueden alterar la química del cloro estratosférico, aunque su efecto de activación o desactivación depende de las condiciones de iluminación. La vida media atmosférica de los clorofluorocarbonos determina la disponibilidad de las sustancias que destruyen el ozono en la estratosfera y depende de la circulación de Brewer-Dobson, que a su vez establece a qué altitudes y por cuánto tiempo está expuesta una porción de aire a la fotoquímica. Por su parte, los gases orgánicos clorados pueden usarse como trazadores para estimar la edad del aire estratosférico y así examinar la circulación de Brewer-Dobson. El uso de métodos complementarios de medición ha sido esencial para ampliar nuestros conocimientos sobre los compuestos clorados en la estratosfera. El ClO se mide principalmente con métodos de percepción remota en las regiones del infrarrojo y de microondas. Las bandas del infrarrojo lejano son ideales para medir el HOCl, pero también se encuentra información sustancial en las regiones de microondas y del infrarrojo medio. El ClONO 2 se mide sólo en el infrarrojo térmico, en tanto que el HCl se puede observar en las regiones de microondas y del infrarrojo lejano y medio. Sin embargo, las bandas del HCl en el infrarrojo medio se encuentran en longitudes de onda en que la radiación de cuerpo negro a temperaturas terrestres es tan baja que el HCl sólo se puede detectar mediante la técnica de absorción solar. Los clorofluorocarbonos se miden con mayor exactitud utilizando métodos de muestreo in situ, aunque para lograr una cobertura global se requieren mediciones en el infrarrojo térmico realizadas desde satélites. En términos epistemológicos, la investigación de la química de la estratosfera y el papel específico de los compuestos clorados se ha basado en distintos conceptos científicos como el razonamiento deductivo, el falsacionismo, el razonamiento abductivo y la llamada "solución de enigmas dentro de la ciencia normal". Sin embargo, la concepción estructuralista de la visión no enunciativa de las teorías es probablemente la que mejor se aplica a la investigación de ...

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Latitudinal distribution of upper stratospheric ClO as derived from Space Borne Microwave Spectroscopy

Cited by 15 publications

References 17 publications

A global inventory of stratospheric chlorine in 2004

A global inventory of stratospheric chlorine in 2004

Ozone depletion and chlorine activation in the Arctic winter 1999/2000 observed in Ny‐Ålesund

Chlorine in the stratosphere

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