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David Wilmouth's Publications
Wilmouth, D. M., F. F. Østerstrøm, J. B. Smith, J. G. Anderson, and R. J. Salawitch, Impact of the Hunga Tonga volcanic eruption on stratospheric composition. PNAS (Proc. Natl. Acad. Sci. USA), 46, e2301994120, 2023, doi: 10.1073/pnas.2301994120.
Østerstrøm, F. F., J. E. Klobas, R. P. Kennedy, A. Cadoux, and D. M. Wilmouth, Sensitivity of stratospheric ozone to the latitude, season, and halogen content of a contemporary explosive volcanic eruption. Nature Sci. Rep., 13, 6457, 2023, doi: 10.1038/s41598-023-32574-9.
We present a systematic evaluation of the perturbation to the stratosphere from an explosive volcanic eruption injecting sulfur dioxide into the atmosphere, as a function of latitude, season, and injection gas halogen content in a chemistry-climate state representative of the present day (modeled as year 2025). Enhancements in aerosol surface area density and decreases in stratospheric ozone are...
Vijayakumar, S., and D. M. Wilmouth, Kinetics of the reactions of chlorinated Very Short-Lived Substances (VSLSs) with chlorine atoms. J. Phys. Chem. A, 127, 7284–7294, 2023, doi: 10.1021/acs.jpca.3c02200.
See abstract at https://doi.org/10.1021/acs.jpca.3c02200.
Homeyer, C. R., J. B. Smith, K. M. Bedka, K. P. Bowman, D. M. Wilmouth, R. Ueyama, J. M. Dean-Day, J. M. St. Clair, R. Hannun, J. Hare, A. Pandey, D. S. Sayres, T. F. Hanisco, A. E. Gordon, and E. N. Tinney, Extreme altitudes of stratospheric hydration by midlatitude convection observed during the DCOTSS field campaign. Geophys. Res. Lett., 50, e2023GL104914, 2023, doi: 10.1029/2023GL104914.
Water vapor's contribution to Earth's radiative forcing is most sensitive to changes in its lower stratosphere concentration. One recognized pathway for rapid increases in stratospheric water vapor is tropopause-overshooting convection. Since this pathway has been rarely sampled, the NASA Dynamics and Chemistry of the Summer Stratosphere (DCOTSS) field project focused on obtaining in situ...
Vijayakumar, S., Ranasinghe, D. S., and D. M. Wilmouth, Kinetics of the reactions of ozone with halogen atoms in the stratosphere. Atmosphere, 12, 1053, 2021, doi: 10.3390/atmos12081053.
See abstract at https://doi.org/10.3390/atmos12081053.
Vijayakumar, S., and D. M. Wilmouth, Atmospheric fate of formyl chloride and mechanisms of the gas-phase reactions with OH radicals and Cl atoms. Chem. Phys. Lett., 777, 138709, 2021, doi: 10.1016/j.cplett.2021.138709.
See abstract at https://doi.org/10.1016/j.cplett.2021.138709.
Klobas, J. E., J. Hansen, D. K. Weisenstein, R. P. Kennedy, and D. M. Wilmouth, Sensitivity of iodine-mediated stratospheric ozone loss chemistry to future chemistry-climate scenarios. Front. Earth Sci., 9, 617586, 2021, doi: 10.3389/feart.2021.617586.
As the chemical and physical state of the stratosphere evolves, so too will the rates of important ozone-destroying reactions. In this work, we evaluate the chemistry-climate sensitivity of reactions of stratospheric iodine, reporting the iodine alpha factor (the efficiency of ozone loss mediated by a single iodine atom relative to the ozone loss mediated by a single chlorine atom) and the iodine...
Wilmouth, D. M., and D. S. Sayres, Determination of Rayleigh scattering cross sections and indices of refraction for Ar, CO2, SF6, and CH4 using BBCES in the ultraviolet. J. Quant. Spectrosc. Radiat. Transfer, 255, 107224, 2020, doi:10.1016/j.jqsrt.2020.107224.
Accurate Rayleigh scattering cross sections are important for understanding the propagation of electromagnetic radiation in planetary atmospheres and for calibrating mirror reflectivity in high finesse optical cavities. In this study, we used Broadband Cavity Enhanced Spectroscopy (BBCES) to measure Rayleigh scattering cross sections for argon, carbon dioxide, sulfur hexafluoride, and...
Klobas, J. E., D. K. Weisenstein, R. J. Salawitch, and D. M. Wilmouth, Reformulating the bromine alpha factor and equivalent effective stratospheric chlorine (EESC): Evolution of ozone destruction rates of bromine and chlorine in future climate scenarios. Atmos. Chem. Phys., 20, 9459–9471, 2020, doi: 10.5194/acp-20-9459-2020.
Future trajectories of the stratospheric trace gas background will alter the rates of bromine- and chlorine-mediated catalytic ozone destruction via changes in the partitioning of inorganic halogen reservoirs and the underlying temperature structure of the stratosphere. The current formulation of the bromine alpha factor, the ozone-destroying power of stratospheric bromine atoms relative to...
Klobas, J. E. and Wilmouth, D. M.: UV spectroscopic determination of the chlorine monoxide (ClO) ∕ chlorine peroxide (ClOOCl) thermal equilibrium constant, Atmos. Chem. Phys., 19, 6205–6215, https://doi.org/10.5194/acp-19-6205-2019, 2019.
The thermal equilibrium constant between the chlorine monoxide radical (ClO) and its dimer, chlorine peroxide (ClOOCl), was determined as a function of temperature between 228–301K in a discharge flow apparatus using broadband UV absorption spectroscopy. A third law fit of the equilibrium values determined from the experimental data provides the expression: Keq = 2.16×10−27 e(8533±...