Parameterization of middle atmospheric water vapor photochemistry for high-altitude NWP and data assimilation

McCormack, J. P.; Hoppel, K. W.; Siskind, D. E.

doi:10.5194/acp-8-7519-2008

Cited by 25 publications

(21 citation statements)

References 39 publications

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“…Considerable averaging over many individual limb profiles was required in order to achieve the published height profiles. A similar equatorial seasonal variation was observed in the H 2 O profiles measured with the MLS instrument on the Aura spacecraft (McCormack et al, 2008). At solstice the Aura group recommended an H 2 O mixing ratio at 90 km of approximately 1 ppm.…”

Section: Msao Data Driving the Model Simulationsupporting

confidence: 67%

The roles of vertical advection and eddy diffusion in the equatorial mesospheric semi-annual oscillation (MSAO)

et al. 2013

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Observations of the mesospheric semi-annual oscillation (MSAO) in the equatorial region have been reported dating back several decades. Seasonal variations in both species densities and airglow emissions are well documented. The extensive observations available offer an excellent case study for comparison with model simulations. A broad range of MSAO measurements is summarised with emphasis on the 80–100 km region. The objective here is not to address directly the complicated driving forces of the MSAO, but rather to employ a combination of observations and model simulations to estimate the limits of some of the underlying dynamical processes. Photochemical model simulations are included for near-equinox and near-solstice conditions, the two times with notable differences in the observed MSAO parameters. Diurnal tides are incorporated in the model to facilitate comparisons of observations made at different local times. The roles of water vapour as the "driver" species and ozone as the "response" species are examined to test for consistency between the model results and observations. The simulations suggest the interactions between vertical eddy diffusion and background vertical advection play a significant role in the MSAO phenomenon. Further, the simulations imply there are rigid limits on vertical advection rates and eddy diffusion rates. For August at the Equator, 90 km altitude, the derived eddy diffusion rate is approximately 1 × 10⁶ cm² s⁻¹ and the vertical advection is upwards at 0.8 cm s⁻¹. For April the corresponding values are 4 × 10⁵ cm² s⁻¹ and 0.1 cm s⁻¹. These results from the current 1-D model simulations will need to be verified by a full 3-D simulation. Exactly how vertical advection and eddy diffusion are related to gravity wave momentum as discussed by Dunkerton (1982) three decades ago remains to be addressed

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Section: Msao Data Driving the Model Simulationsupporting

confidence: 67%

The roles of vertical advection and eddy diffusion in the equatorial mesospheric semi-annual oscillation (MSAO)

et al. 2013

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“…These papers have studied major stratospheric warmings based on observations of tracers, meteorological analyses of geopotential height, temperature and horizontal winds, and fields of potential vorticity (PV) derived from meteorological analyses. However, to our knowledge, major warmings have not been studied hitherto using analyses of stratospheric water vapour produced using data assimilation, chiefly because it is only recently that such analyses have started to become available and be evaluated (Juckes, 2007;Lahoz et al, 2007a, b;McCormack et al, 2008;Eckermann et al, 2009;Thornton et al, 2009). The lack of operational observations of stratospheric water vapour for NWP (Numerical Weather Prediction) centres to assimilate contributes to the scarcity of published research on stratospheric water vapour analyses.…”

Section: Introductionmentioning

confidence: 99%

“…Data assimilation has been used successfully to produce analyses of stratospheric constituents such as ozone and water vapour; evaluate observations of stratospheric chemical constituents; and evaluate chemical models. Papers describing this work include (the list is not exhaustive) Fisher and Lary (1995), Khattatov et al (2000), Errera and Fonteyn (2001), Dethof and Hólm (2004), Geer et al (2006Geer et al ( , 2007, Lahoz et al (2007a, b), Jackson (2007), McCormack et al (2008), Eckermann et al (2009), Thornton et al (2009) and Lahoz and Errera (2010). The review by Lahoz et al (2007a) includes a comprehensive list of references.…”

Section: Introductionmentioning

confidence: 99%

The 2009 stratospheric major warming described from synergistic use of BASCOE water vapour analyses and MLS observations

et al. 2011

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Abstract. The record-breaking major stratospheric warming of northern winter 2009 (January-February) is studied using BASCOE (Belgian Assimilation System for Chemical ObsErvation) stratospheric water vapour analyses and MLS (Microwave Limb Sounder) water vapour observations, together with meteorological data from the European Centre for Medium-Range Weather Forecasts (ECMWF) and potential vorticity (PV) derived from ECMWF meteorological data. We focus on the interaction between the cyclonic wintertime stratospheric polar vortex and subsidiary anticyclonic stratospheric circulations during the build-up, peak and aftermath of the major warming. We show dynamical consistency between the water vapour analysed fields and the meteorological and PV fields. Using various approaches, we use the analysed water vapour fields to estimate descent in the polar vortex during this period of between ∼0.5 km day −1 and ∼0.7 km day −1 . New results include the analysis of water vapour during the major warming and demonstration of the benefit of assimilating MLS satellite data into the BASCOE model.

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“…(1) could be replaced or supplemented by an explicit parameterization of the chemical loss of H 2 O, mostly via photolysis and the reaction with O( 1 D); see MacKenzie and Harwood (2004) and McCormack et al (2008). In the simplified methane chemistry of EMAC, for example, a predefined O( 1 D) is also used for the reaction with CH 4 and could be reused for the reaction with H 2 O.…”

Section: Recommendations For Gcms Without Online Chemistrymentioning

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.

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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.

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Parameterization of middle atmospheric water vapor photochemistry for high-altitude NWP and data assimilation

Cited by 25 publications

References 39 publications

The roles of vertical advection and eddy diffusion in the equatorial mesospheric semi-annual oscillation (MSAO)

The roles of vertical advection and eddy diffusion in the equatorial mesospheric semi-annual oscillation (MSAO)

The 2009 stratospheric major warming described from synergistic use of BASCOE water vapour analyses and MLS observations

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

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Parameterization of middle atmospheric water vapor photochemistry for high-altitude NWP and data assimilation

Cited by 25 publications

References 39 publications

The roles of vertical advection and eddy diffusion in the equatorial mesospheric semi-annual oscillation (MSAO)

The roles of vertical advection and eddy diffusion in the equatorial mesospheric semi-annual oscillation (MSAO)

The 2009 stratospheric major warming described from synergistic use of BASCOE water vapour analyses and MLS observations

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

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