Are Vibrationally Excited Molecules a Clue for the “O₃ Deficit Problem” and “HO_x Dilemma” in the Middle Atmosphere?

Abstract

Stretched oxygen and odd hydrogen species are suggested to offer a clue to explain the so-called "ozone deficit problem" and "HO x dilemma" in the upper stratosphere and mesosphere under conditions of local thermodynamic disequilibrium.

Stratospheric and mesospheric HO<sub>2</sub> observations from the Aura Microwave Limb Sounder

“…However, Canty et al (2006) concluded that, at least between 25 and 60 km, the HO x Microwave Limb Sounder (MLS) and FIRS-2 observations were reasonably well described by photochemical models. In addition to these modelling discrepancies (a problem known as the HO x dilemma), models have consistently underpredicted the amounts of O 3 at such altitudes, an issue known as the O 3 deficit problem (Crutzen and Schmailzl, 1983;Solomon et al, 1983;Eluszkiewicz and Allen, 1993;Summers et al, 1997;Varandas, 2004;Siskind et al, 2013).…”

“…Miller et al, 1994;Jucks et al, 1998;Varandas, 2004); however, difficulties persist, in part because there are very few observations of HO 2 in the mesosphere. To date, there are four mesospheric data sets available: (1) 6 days spread between April 1992 and December 1996 measured by the Kitt Peak National Radio Astronomy Observatory (NRAO) (Sandor et al, 1998), (2) the Sub-Millimeter Radiometer (SMR) aboard the Odin satellite data set (Baron et al, 2009), which consists of one observation period of 24 h each month between October 2003 and December 2005, (3) the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) data set (Kikuchi et al, 2010), which provides daily coverage from 38 • S to 65 • N between October 2009 and April 2010, and (4) the standard MLS data set (Pickett et al, , 2008, which provides coverage mostly from 55 • S to 55 • N, up to 0.046 hPa and only during daytime.…”

Dynamics Study of the OH + O3 Atmospheric Reaction with Both Reactants Vibrationally Excited

“…Moreover, the high-energy regimes involved and the quality of previous results 10 (for cases as extreme as H + H 2 , see ref 30 and references therein) suggest that the QCT approach is here too well justified. The paper is organized as follows.…”

“…Uncovering their dynamics also greatly enhances our understanding of areas with practical interest, namely, atmospheric chemistry, combustion, and unimolecular decomposition of activated species. [1][2][3][4][5][6][7][8][9][10][11][12] Of particular importance is the role of internal energy in the collisional process, especially for energies close to the dissociation threshold. Indeed, the internal-energy dependence holds important information about the behavior of the colliding species, providing clues for the microscopic details of the intermolecular energy transfer.…”

Do vibrationally excited OH molecules affect middle and upper atmospheric chemistry?

“…The impact of vibrational excitation on atmospheric chemistry has been investigated extensively for vibrationally excited O 2 (e.g. Slanger et al, 1988;Toumi et al, 1991;Toumi, 2008;Shi and Barker, 1992;Mlynczak and Solomon, 1993;Slanger, 1994;Miller et al, 1994;Patten Jr. et al, 1994;Toumi et al, 1996;Zipf and Prasad, 1998) Hierl et al, 1997;Delmdahl et al, 1998;Varandas and Zhang, 2001;Varandas, 2002Varandas, , 2004aChen and Marcus, 2006;Vadas and Fritts, 2008;Prasad and Zipf, 2008), and results were in some cases under heavy dispute (Smith and Copeland, 2004;Varandas, 2005). Atmospheric chemistry models, particularly those developed for stratospheric ozone chemistry and later extended towards the upper atmosphere, usually neglect this effect (e.g., SLIMCAT, Chipperfield, 1999;MOZART, Horowitz et al, 2003;MESSy, Jöckel et al, 2005;REPROBUS, Lefèvre et al, 1994;CLAMS, McKenna et al, 2002).…”