Doubled CO2 effects on NOy in a coupled 2D model

Rosenfield, Joan E.; Douglass, Anne R.

doi:10.1029/1998gl900147

Cited by 46 publications

(52 citation statements)

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“…Their findings are consistent with our observations at Jungfraujoch: they showed that the NO 2 /NO partitioning is currently changing with time to favor NO, due to stratospheric cooling, which slows the NO + O 3 → NO 2 + O 2 reaction, and decreasing ClO concentrations, which slows the NO + ClO → NO 2 + Cl reaction. It should be noted that a stratospheric cooling can also decrease the amount of NO y in the stratosphere from N 2 O (Rosenfield and Douglass, 1998).…”

Section: Resultsmentioning

confidence: 99%

Analysis of stratospheric NO2 trends above Jungfraujoch using ground-based UV-visible, FTIR, and satellite nadir observations

et al. 2012

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Abstract. The trend in stratospheric NO 2 column at the NDACC (Network for the Detection of Atmospheric Composition Change) station of Jungfraujoch (46.5 • N, 8.0 • E) is assessed using ground-based FTIR and zenith-scattered visible sunlight SAOZ measurements over the period 1990 to 2009 as well as a composite satellite nadir data set constructed from ERS-2/GOME, ENVISAT/SCIAMACHY, and METOP-A/GOME-2 observations over the 1996-2009 period. To calculate the trends, a linear least squares regression model including explanatory variables for a linear trend, the mean annual cycle, the quasi-biennial oscillation (QBO), solar activity, and stratospheric aerosol loading is used. For the 1990-2009 period, statistically indistinguishable trends of −3.7 ± 1.1 % decade −1 and −3.6 ± 0.9 % decade −1 are derived for the SAOZ and FTIR NO 2 column time series, respectively. SAOZ, FTIR, and satellite nadir data sets show a similar decrease over the 1996-2009 period, with trends of −2.4 ± 1.1 % decade −1 , −4.3 ± 1.4 % decade −1 , and −3.6 ± 2.2 % decade −1 , respectively. The fact that these declines are opposite in sign to the globally observed +2.5 % decade −1 trend in N 2 O, suggests that factors other than N 2 O are driving the evolution of stratospheric NO 2 at northern mid-latitudes. Possible causes of the decrease in stratospheric NO 2 columns have been investigated. The most likely cause is a change in the NO 2 /NO partitioning in favor of NO, due to a possible stratospheric cooling and a decrease in stratospheric chlorine content, the latter being further confirmed by the negative trend in the ClONO 2 column derived from FTIR observations at Jungfraujoch. Decreasing ClO concentrations slows the NO + ClO → NO 2 + Cl reaction and a stratospheric cooling slows the NO + O 3 → NO 2 + O 2 reaction, leaving more NO x in the form of NO. The slightly positive trends in ozone estimated from ground-and satellitebased data sets are also consistent with the decrease of NO 2 through the NO 2 + O 3 → NO 3 + O 2 reaction. Finally, we cannot rule out the possibility that a strengthening of the Dobson-Brewer circulation, which reduces the time available for N 2 O photolysis in the stratosphere, could also contribute to the observed decline in stratospheric NO 2 above Jungfraujoch.

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Section: Resultsmentioning

confidence: 99%

Analysis of stratospheric NO2 trends above Jungfraujoch using ground-based UV-visible, FTIR, and satellite nadir observations

et al. 2012

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“…For example, the sink for NO x is temperature dependent, so CO 2 -induced cooling of the stratosphere decreases NO x abundances by slowing the highly temperature-dependent Reaction (R1) (below). The subsequent increase in N leads to an increase in the rate of Reaction (R2), therefore decreasing NO x abundances (Rosenfield and Douglass, 1998).…”

Section: Introductionmentioning

confidence: 99%

The sensitivity of stratospheric ozone changes through the 21st century to N2O and CH4

et al. 2012

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Abstract. Through the 21st century, anthropogenic emissions of the greenhouse gases N 2 O and CH 4 are projected to increase, thus increasing their atmospheric concentrations. Consequently, reactive nitrogen species produced from N 2 O and reactive hydrogen species produced from CH 4 are expected to play an increasingly important role in determining stratospheric ozone concentrations. Eight chemistry-climate model simulations were performed to assess the sensitivity of stratospheric ozone to different emissions scenarios for N 2 O and CH 4 . Global-mean total column ozone increases through the 21st century in all eight simulations as a result of CO 2 -induced stratospheric cooling and decreasing stratospheric halogen concentrations. Larger N 2 O concentrations were associated with smaller ozone increases, due to reactive nitrogen-mediated ozone destruction. In the simulation with the largest N 2 O increase, global-mean total column ozone increased by 4.3 DU through the 21st century, compared with 10.0 DU in the simulation with the smallest N 2 O increase. In contrast, larger CH 4 concentrations were associated with larger ozone increases; global-mean total column ozone increased by 16.7 DU through the 21st century in the simulation with the largest CH 4 concentrations and by 4.4 DU in the simulation with the lowest CH 4 concentrations. CH 4 leads to ozone loss in the upper and lower stratosphere by increasing the rate of reactive hydrogen-mediated ozone loss cycles, however in the lower stratosphere and troposphere, CH 4 leads to ozone increases due to photochemical smogtype chemistry. In addition to this mechanism, total column ozone increases due to H 2 O-induced cooling of the stratosphere, and slowing of the chlorine-catalyzed ozone loss cycles due to an increased rate of the CH 4 + Cl reaction. Stratospheric column ozone through the 21st century exhibits a near-linear response to changes in N 2 O and CH 4 surface concentrations, which provides a simple parameterization for the ozone response to changes in these gases.

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“…The former is strongly influenced by cooling of the stratosphere (Rosenfield and Douglass, 1998) and by changes in the strength of the BDC (Cook and Roscoe, 2012).…”

Section: Changes In No X Destruction Ratesmentioning

confidence: 99%

Drivers of hemispheric differences in return dates of mid-latitude stratospheric ozone to historical levels

et al. 2013

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Chemistry-climate models (CCMs) project an earlier return of northern mid-latitude total column ozone to 1980 values compared to the southern mid-latitudes. The chemical and dynamical drivers of this hemispheric difference are investigated in this study. The hemispheric asymmetry in return dates is a robust result across different CCMs and is qualitatively independent of the method used to estimate return dates. However, the differences in dates of return to 1980 levels between the southern and northern mid-latitudes can vary between 0 and 30 yr across the range of CCM projections analyzed. Positive linear trends in ozone lead to an earlier return of ozone than expected from the return of Cl_y to 1980 levels. This forward shift is stronger in the Northern than in the Southern Hemisphere because (i) trends have a larger effect on return dates if the sensitivity of ozone to Cl_y is lower and (ii) the trends in the Northern Hemisphere are stronger than in the Southern Hemisphere. An attribution analysis performed with two CCMs shows that chemically-induced changes in ozone are the major driver of the earlier return of ozone to 1980 levels in northern mid-latitudes; therefore transport changes are of minor importance. This conclusion is supported by the fact that the spread in the simulated hemispheric difference in return dates across an ensemble of twelve models is only weakly related to the spread in the simulated hemispheric asymmetry of trends in the strength of the Brewer–Dobson circulation. The causes for chemically-induced asymmetric ozone trends relevant for the total column ozone return date differences are found to be (i) stronger increases in ozone production due to enhanced NO_x concentrations in the Northern Hemisphere lowermost stratosphere and troposphere, (ii) stronger decreases in the destruction rates of ozone by the NO_x cycle in the Northern Hemisphere lower stratosphere linked to effects of dynamics and temperature on NO_x concentrations, and (iii) an increasing efficiency of heterogeneous ozone destruction by Cl_y in the Southern Hemisphere mid-latitudes as a~result of decreasing lower stratospheric temperatures

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Doubled CO₂ effects on NO_y in a coupled 2D model

Cited by 46 publications

References 11 publications

Analysis of stratospheric NO<sub>2</sub> trends above Jungfraujoch using ground-based UV-visible, FTIR, and satellite nadir observations

Analysis of stratospheric NO<sub>2</sub> trends above Jungfraujoch using ground-based UV-visible, FTIR, and satellite nadir observations

The sensitivity of stratospheric ozone changes through the 21st century to N<sub>2</sub>O and CH<sub>4</sub>

Drivers of hemispheric differences in return dates of mid-latitude stratospheric ozone to historical levels

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Doubled CO2 effects on NOy in a coupled 2D model

Cited by 46 publications

References 11 publications

Analysis of stratospheric NO&lt;sub&gt;2&lt;/sub&gt; trends above Jungfraujoch using ground-based UV-visible, FTIR, and satellite nadir observations

Analysis of stratospheric NO&lt;sub&gt;2&lt;/sub&gt; trends above Jungfraujoch using ground-based UV-visible, FTIR, and satellite nadir observations

The sensitivity of stratospheric ozone changes through the 21st century to N&lt;sub&gt;2&lt;/sub&gt;O and CH&lt;sub&gt;4&lt;/sub&gt;

Drivers of hemispheric differences in return dates of mid-latitude stratospheric ozone to historical levels

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Doubled CO₂ effects on NO_y in a coupled 2D model

Analysis of stratospheric NO<sub>2</sub> trends above Jungfraujoch using ground-based UV-visible, FTIR, and satellite nadir observations

Analysis of stratospheric NO<sub>2</sub> trends above Jungfraujoch using ground-based UV-visible, FTIR, and satellite nadir observations

The sensitivity of stratospheric ozone changes through the 21st century to N<sub>2</sub>O and CH<sub>4</sub>