Understanding the Changes of Stratospheric Water Vapor in Coupled Chemistry–Climate Model Simulations

Oman, Luke D.; Waugh, Darryn W.; Pawson, Steven; Stolarski, R. S.; Nielsen, J. E.

doi:10.1175/2008jas2696.1

Cited by 57 publications

(81 citation statements)

References 24 publications

(32 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, a detailed understanding of the two contributions is required to assess how well Climate Models simulate stratospheric dynamics and tracer transport, and to increase the confidence in their projections. Castanheira and Gimeno (2011) and Peevey et al (2012) showed that double tropopause events (DTs) are associated with Rossby waves in the subtropics and midlatitudes. These waves can produce intrusions of tropical tropospheric air into the extratropical lower stratosphere (Randel et al, 2007;Pan et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

“…Castanheira and Gimeno (2011) and Peevey et al (2012) showed that double tropopause events (DTs) are associated with Rossby waves in the subtropics and midlatitudes. These waves can produce intrusions of tropical tropospheric air into the extratropical lower stratosphere (Randel et al, 2007;Pan et al, 2009). If these waves break they will contribute to the exchange of trace gases, such as ozone or water vapour, between the troposphere and the stratosphere through irreversible mixing (Pan et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Relationships between Brewer-Dobson circulation, double tropopauses, ozone and stratospheric water vapour

et al. 2012

View full text Add to dashboard Cite

Abstract. Statistical relationships between the variability of the area covered by double tropopause events (DTs), the strength of the tropical upwelling, the total column ozone and of the lower stratospheric water vapour are analyzed. The QBO and ENSO signals in the double tropopause and tropical upwelling as well as their influence on the statistical relationships are also presented. The analysis is based on both reanalysed data (ERA-Interim) and satellite data.Significant anticorrelations were found between the area covered by DTs and the total column ozone in the midlatitudes of the Northern Hemisphere. This relationship is confirmed by a large positive correlation between the areas covered by ozone laminae and double tropopause events as found in the HIRDLS satellite dataset. Significant anticorrelations were also found between the global area of double tropopause events and the near global (50 • S-50 • N) water vapour in the lower stratosphere.The correlations of DT variables with total column ozone and ozone laminae are both consistent with the poleward displacement of tropical air with lower ozone mixing ratio and with tropospheric intrusions of tropical tropospheric air into the lower extratropical stratosphere. The association of DTs with the poleward displacements of the tropical air is also consistent with a strong positive correlation between the area covered by DTs and the wave activity in the lower most stratosphere, between the first and second lapse rate tropopauses, as found in the ERA-Interim reanalysis.Finally, a significant anticorrelation was found between the tropical upwelling and the near global lower stratospheric water vapour. Moreover, the step like decrease in the lower stratospheric water vapour after 2001 is mirrored by a step like increase in the tropical upwelling.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Relationships between Brewer-Dobson circulation, double tropopauses, ozone and stratospheric water vapour

et al. 2012

View full text Add to dashboard Cite

show abstract

“…Water vapour will also play a role -affecting the radiative balance of the stratosphere and, as a source of HO x (OH+HO 2 ), playing an important role in ozone chemistry, particularly in the upper stratosphere. The concentration of stratospheric H 2 O may be affected by changes to the tropospheric concentration of CH 4 or the amount of H 2 O entering the stratosphere through the "cold trap" around the tropical tropopause (Austin et al, 2007;Oman et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Quantifying the contributions to stratospheric ozone changes from ozone depleting substances and greenhouse gases

et al. 2010

View full text Add to dashboard Cite

Abstract.A state-of-the-art chemistry climate model coupled to a three-dimensional ocean model is used to produce three experiments, all seamlessly covering the period 1950-2100, forced by different combinations of long-lived Greenhouse Gases (GHGs) and Ozone Depleting Substances (ODSs). The experiments are designed to quantify the separate effects of GHGs and ODSs on the evolution of ozone, as well as the extent to which these effects are independent of each other, by alternately holding one set of these two forcings constant in combination with a third experiment where both ODSs and GHGs vary. We estimate that up to the year 2000 the net decrease in the column amount of ozone above 20 hPa is approximately 75% of the decrease that can be attributed to ODSs due to the offsetting effects of cooling by increased CO 2 . Over the 21st century, as ODSs decrease, continued cooling from CO 2 is projected to account for more than 50% of the projected increase in ozone above 20 hPa. Changes in ozone below 20 hPa show a redistribution of ozone from tropical to extra-tropical latitudes with an increase in the Brewer-Dobson circulation. In addition to a latitudinal redistribution of ozone, we find that the globally averaged column amount of ozone below 20 hPa decreases over the 21st century, which significantly mitigates the effect of upper stratospheric cooling on total column ozone. Analysis by linear regression shows that the recovery of ozone from the effects of ODSs generally follows the decline in reactive chlorine and bromine levels, with the exception of the lower polar stratosphere where recovery of ozone in the second half of the 21st century is slower than would be indicated by the decline in reactive chlorine and bromine concentraCorrespondence to: D. A. Plummer (david.plummer@ec.gc.ca) tions. These results also reveal the degree to which GHGrelated effects mute the chemical effects of N 2 O on ozone in the standard future scenario used for the WMO Ozone Assessment. Increases in the residual circulation of the atmosphere and chemical effects from CO 2 cooling more than halve the increase in reactive nitrogen in the mid to upper stratosphere that results from the specified increase in N 2 O between 1950 and 2100.

show abstract

“…Still, for reasons of simplification, several GCMs use the approximation that the yield of H 2 O from CH 4 oxidation is exactly 2 (Monge- Sanz et al, 2013;ECMWF, 2007;Austin et al, 2007;Oman et al, 2008;Boville et al, 2001;Mote, 1995;Eichinger et al, 2015). In the ECHAM/MESSy Atmospheric Chemistry (EMAC) model , for example, explicitly configured in a CTM-like setup without interactive chemistry, the production of SWV from CH 4 oxidation is calculated in a simplified way using a specifically introduced CH 4 tracer (by applying the CH 4 submodel) according to Hurst et al (1999) and the yield of le Texier et al (1988) also do not agree well in the lower stratosphere, which can indeed be explained by the indistinguishable inputs from H 2 and CH 4 oxidation in observations as stated before.…”

Section: Introductionmentioning

confidence: 99%

Investigating the yield of H<sub>2</sub>O and H<sub>2</sub> from methane oxidation in the stratosphere

Frank¹,

Jöckel²,

Gromov³

et al. 2018

Atmos. Chem. Phys.

View full text Add to dashboard Cite

Abstract. An important driver of climate change is stratospheric water vapor (SWV), which in turn is influenced by the oxidation of atmospheric methane (CH 4 ). In order to parameterize the production of water vapor (H 2 O) from CH 4 oxidation, it is often assumed that the oxidation of one CH 4 molecule yields exactly two molecules of H 2 O. However, this assumption is based on an early study, which also gives evidence that this is not true at all altitudes.In the current study, we re-evaluate this assumption with a comprehensive systematic analysis using a stateof-the-art chemistry-climate model (CCM), namely the ECHAM/MESSy Atmospheric Chemistry (EMAC) model, and present three approaches to investigate the yield of H 2 O and hydrogen gas (H 2 ) from CH 4 oxidation. We thereby make use of the Module Efficiently Calculating the Chemistry of the Atmosphere (MECCA) in a box model and global model configuration. Furthermore, we use the kinetic chemistry tagging technique (MECCA-TAG) to investigate the chemical pathways between CH 4 , H 2 O and H 2 , by being able to distinguish hydrogen atoms produced by CH 4 from H 2 from other sources.We apply three approaches, which all agree that assuming a yield of 2 overestimates the production of H 2 O in the lower stratosphere (calculated as 1.5-1.7). Additionally, transport and subsequent photochemical processing of longer-lived intermediates (mostly H 2 ) raise the local yield values in the upper stratosphere and lower mesosphere above 2 (maximum > 2.2). In the middle and upper mesosphere, the influence of loss and recycling of H 2 O increases, making it a crucial factor in the parameterization of the yield of H 2 O from CH 4 oxidation. An additional sensitivity study with the Chemistry As A Boxmodel Application (CAABA) shows a dependence of the yield on the hydroxyl radical (OH) abundance. No significant temperature dependence is found. We focus representatively on the tropical zone between 23 • S and 23 • N. It is found in the global approach that presented results are mostly valid for midlatitudes as well. During the polar night, the method is not applicable.Our conclusions question the use of a constant yield of H 2 O from CH 4 oxidation in climate modeling and encourage to apply comprehensive parameterizations that follow the vertical profiles of the H 2 O yield derived here and take the chemical H 2 O loss into account.

show abstract

Understanding the Changes of Stratospheric Water Vapor in Coupled Chemistry–Climate Model Simulations

Cited by 57 publications

References 24 publications

Relationships between Brewer-Dobson circulation, double tropopauses, ozone and stratospheric water vapour

Relationships between Brewer-Dobson circulation, double tropopauses, ozone and stratospheric water vapour

Quantifying the contributions to stratospheric ozone changes from ozone depleting substances and greenhouse gases

Investigating the yield of H<sub>2</sub>O and H<sub>2</sub> from methane oxidation in the stratosphere

Contact Info

Product

Resources

About

Understanding the Changes of Stratospheric Water Vapor in Coupled Chemistry–Climate Model Simulations

Cited by 57 publications

References 24 publications

Relationships between Brewer-Dobson circulation, double tropopauses, ozone and stratospheric water vapour

Relationships between Brewer-Dobson circulation, double tropopauses, ozone and stratospheric water vapour

Quantifying the contributions to stratospheric ozone changes from ozone depleting substances and greenhouse gases

Investigating the yield of H&lt;sub&gt;2&lt;/sub&gt;O and H&lt;sub&gt;2&lt;/sub&gt; from methane oxidation in the stratosphere

Contact Info

Product

Resources

About

Investigating the yield of H<sub>2</sub>O and H<sub>2</sub> from methane oxidation in the stratosphere