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Water adsorption on atmospheric clay minerals as a function of relative humidity: Application of experimental results to Adsorption Activation Theory
Presenter: Courtney D. Hatch, Department of Chemistry, Hendrix College, Conway, Arkansas
Co-Authors: Annie L. Greenaway, Kenneth J. Harris, Matthew Christie
The indirect aerosol effect on climate includes radiative effects from aerosol particles that take up water and form cloud droplets or alter the radiative properties and lifetimes of clouds. This effect is currently one of the largest uncertainties in understanding climate change. In the past, atmospheric climate models have neglected the potentially significant effect of mineral dust aerosol on the indirect climate effect. However, a number of recent studies have revealed the importance of adsorbed water on the cloud condensation nuclei (CCN) activity of insoluble dust particles. Additionally, the recently developed FHH-Adsorption Activation Theory has been used to explain CCN activity of insoluble particles and has been applied to atmospheric models to account for the contribution of insoluble particles to cloud droplet number concentration (CDNC). However, the model results appear to be highly sensitive to the adsorption parameters. In the current work, water adsorption on the three most abundant clay minerals found in the atmosphere using an ATR-FTIR equipped with a flow cell were measured in the laboratory. The FHH adsorption isotherm model was applied to the experimental results to extract experimental FHH adsorption parameters. The adsorption parameters were then used in FHH-Adsorption Activation Theory (FHH-AT) to predict CCN activation of mineral dust aerosol in the atmosphere. The predicted CCN activities for these clays are in excellent agreement with previously reported experimental CCN activity measurements.
About the Presenter:
Dr. Courtney Hatch is currently an assistant professor of chemistry at Hendrix College in Conway, AR, where she completed her B.A. in Chemistry in 2000. She completed her postdoctoral work with Dr. Vicki Grassian and Dr. Gregory Carmichael at the University of Iowa in 2008 and received her Ph.D. from the University of Colorado at Boulder in 2006 under the direction of Dr. Maggie Tolbert. Dr. Hatch’s research interests focus on the chemistry and climate effects of heterogeneous aerosol chemistry, particularly mineral dust aerosol. Additionally, Dr. Hatch’s academic endeavors aim to provide engaging, real-world experiences for undergraduate students that allow them to actualize their full potential as professional scientists.