A study of stratospheric chlorine partitioning based on new satellite measurements and modeling

Santee, M. L.; MacKenzie, Ian A.; Manney, G. L.; Chipperfield, Martyn P.; Bernath, P. F.; Walker, Kaley A.; Boone, C. D.; Froidevaux, L.; Livesey, N. J.; Waters, J. W.

doi:10.1029/2007jd009057

Cited by 104 publications

(153 citation statements)

References 117 publications

(218 reference statements)

Supporting

Mentioning

132

Contrasting

Order By: Relevance

“…The initial titration between HCl and ClONO 2 via Reaction (R1) occurred before June (as usually in the Antarctic; e.g. Santee et al, 2008) so that the model simulation starts with about 1 ppb of ClO x and with near-zero values of ClONO 2 . Little further chemical change occurs ("sleeping chemistry") as long as solar zenith angles are large (until end of July), but with decreasing solar zenith angle, HCl further decreases, leading to increasing ClO x and, subsequently, chemical ozone destruction (e.g.…”

Section: Maintenance Of Chlorine Activationmentioning

confidence: 99%

“…(Salawitch et al, 1988;Crutzen et al, 1992;Portmann et al, 1996). The further chemical activation to near-zero HCl values, as observed in Antarctic winter and in cold winters in the Arctic (Jaeglé et al, 1997;Santee et al, 2005Santee et al, , 2008Manney et al, 2011;Wegner et al, 2012), requires the reproduction of partners (e.g. ClONO 2 or HOCl) for heterogeneous reactions with HCl.…”

Section: Introductionmentioning

confidence: 99%

“…With the return of sunlight to the polar region a period follows, characterised by further activation and maintenance of high levels of active chlorine (as observed; Santee et al, 2005Santee et al, , 2008, during which most of the ozone depletion occurs. Polar stratospheric clouds are measured in the Antarctic lower stratosphere until early October (Pitts et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

“…Because of the initial concentration of HCl (before the onset of heterogeneous reactions) in the polar vortex being greater than that of ClONO 2 (Jaeglé et al, 1997;Santee et al, 2008), the amount of Cl 2 produced…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The maintenance of elevated active chlorine levels in the Antarctic lower stratosphere through HCl null cycles

Müller¹,

Grooß²,

Zafar

et al. 2018

Atmos. Chem. Phys.

View full text Add to dashboard Cite

Abstract. The Antarctic ozone hole arises from ozone destruction driven by elevated levels of ozone destroying ("active") chlorine in Antarctic spring. These elevated levels of active chlorine have to be formed first and then maintained throughout the period of ozone destruction. It is a matter of debate how this maintenance of active chlorine is brought about in Antarctic spring, when the rate of formation of HCl (considered to be the main chlorine deactivation mechanism in Antarctica) is extremely high. Here we show that in the heart of the ozone hole (16-18 km or 85-55 hPa, in the core of the vortex), high levels of active chlorine are maintained by effective chemical cycles (referred to as HCl null cycles hereafter). In these cycles, the formation of HCl is balanced by immediate reactivation, i.e. by immediate reformation of active chlorine. Under these conditions, polar stratospheric clouds sequester HNO 3 and thereby cause NO 2 concentrations to be low. These HCl null cycles allow active chlorine levels to be maintained in the Antarctic lower stratosphere and thus rapid ozone destruction to occur. For the observed almost complete activation of stratospheric chlorine in the lower stratosphere, the heterogeneous reaction HCl + HOCl is essential; the production of HOCl occurs via HO 2 + ClO, with the HO 2 resulting from CH 2 O photolysis. These results are important for assessing the impact of changes of the future stratospheric composition on the recovery of the ozone hole. Our simulations indicate that, in the lower stratosphere, future increased methane concentrations will not lead to enhanced chlorine deactivation (through the reaction CH 4 + Cl −→ HCl+CH 3 ) and that extreme ozone destruction to levels below ≈ 0.1 ppm will occur until mid-century.

show abstract

Section: Maintenance Of Chlorine Activationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The maintenance of elevated active chlorine levels in the Antarctic lower stratosphere through HCl null cycles

Müller¹,

Grooß²,

Zafar

et al. 2018

Atmos. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…Recent observational and modelling studies (eg Dufour et al, 2006;Urban et al, 2006;Santee et al, 2008), which have focused on the northern winter of 2004/05 and other recent winters, have led to a better understanding of stratospheric chlorine partitioning and how both 1834 D. R. JACKSON AND Y. J. ORSOLINI reactive and reservoir chlorine evolves through the polar winter. Previously, many aspects of stratospheric chlorine partitioning had remained uncertain, and the better understanding of this partitioning resulting from these recent papers is essential in better understanding ozone loss and predicting stratospheric ozone loss in the future.…”

Section: Introductionmentioning

confidence: 99%

Estimation of Arctic ozone loss in winter 2004/05 based on assimilation of EOS MLS and SBUV/2 observations

Jackson

Orsolini

2008

Quart J Royal Meteoro Soc

View full text Add to dashboard Cite

ABSTRACT:In this paper we present a new technique for the estimation of ozone loss in the stratospheric polar vortex based on the assimilation of Earth Observing System Microwave Limb Sounder (EOS MLS) and Solar Backscatter Ultraviolet radiometer (SBUV/2) ozone observations in the Met Office data assimilation system. We focus on the northern winter of 2004/05, which was exceptionally cold in the Arctic stratosphere, with associated large ozone depletion due to heterogeneous chemistry. Our ozone loss estimate, which was calculated for the 1 February to 10 March 2005 period, peaks at 450 K (approximately 17-18 km), and is 0.6 ppmv at that isentropic level (our loss estimate for the vortex core only was somewhat higher (1.0 ppmv) and indicates uncertainties related to mixing at the vortex edge). This value is similar to or smaller than results from other studies, which estimate ozone loss in this period to be in the 0.6-1.2 ppmv range. When combined with results from other studies that estimate ozone loss occurring outside our assimilation period, we obtain an estimate of 0.8-1.2 ppmv for ozone loss from early January to early March 2005. We find a second maximum in ozone loss for the 1 February-10 March period near 650 K (approximately 25 km) of around 0.4 ppmv. This is a lower figure than found in other studies, but ozone loss is actually much stronger at this level outside the vortex in a low-ozone pocket in the Aleutian anticyclone, likely due to the NOx catalytic cycle. Our results show that the ozone data assimilation method we have used to estimate ozone loss is very promising, and can lead to potentially more accurate ozone-loss estimates than other methods.

show abstract

Understanding differences in chemistry climate model projections of stratospheric ozone

et al. 2014

View full text Add to dashboard Cite

Chemistry climate models (CCMs) are used to project future evolution of stratospheric ozone as concentrations of ozone-depleting substances (ODSs) decrease and greenhouse gases increase, cooling the stratosphere. CCM projections exhibit not only many common features but also a broad range of values for quantities such as year of ozone return to 1980 and global ozone level at the end of the 21st century. Multiple linear regression is applied to each of 14 CCMs to separate ozone response to ODS concentration change from that due to climate change. We show that the sensitivity of lower stratospheric ozone to chlorine change ΔO 3 /ΔCl y is a near-linear function of partitioning of total inorganic chlorine (Cl y ) into its reservoirs; both Cl y and its partitioning are largely controlled by lower stratospheric transport. CCMs with best performance on transport diagnostics agree with observations for chlorine reservoirs and produce similar ozone responses to chlorine change. After 2035, differences in ΔO 3 /ΔCl y contribute little to the spread in CCM projections as the anthropogenic contribution to Cl y becomes unimportant. Differences among upper stratospheric ozone increases due to temperature decreases are explained by differences in ozone sensitivity to temperature change ΔO 3 /ΔT due to different contributions from various ozone loss processes, each with its own temperature dependence. Ozone decrease in the tropical lower stratosphere caused by a projected speedup in the Brewer-Dobson circulation may or may not be balanced by ozone increases in the middle-and high-latitude lower stratosphere and upper troposphere. This balance, or lack thereof, contributes most to the spread in late 21st century projections.

show abstract

A study of stratospheric chlorine partitioning based on new satellite measurements and modeling

Cited by 104 publications

References 117 publications

The maintenance of elevated active chlorine levels in the Antarctic lower stratosphere through HCl null cycles

The maintenance of elevated active chlorine levels in the Antarctic lower stratosphere through HCl null cycles

Estimation of Arctic ozone loss in winter 2004/05 based on assimilation of EOS MLS and SBUV/2 observations

Understanding differences in chemistry climate model projections of stratospheric ozone

Contact Info

Product

Resources

About