Articles | Volume 25, issue 11
https://doi.org/10.5194/acp-25-5433-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/acp-25-5433-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Counteracting influences of gravitational settling modulate aerosol impacts on cloud-base-lowering fog characteristics
Nathan H. Pope
CORRESPONDING AUTHOR
Department of Land, Air and Water Resources, University of California Davis, Davis, CA, USA
Adele L. Igel
Department of Land, Air and Water Resources, University of California Davis, Davis, CA, USA
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Lucas J. Sterzinger and Adele L. Igel
Atmos. Chem. Phys., 24, 3529–3540, https://doi.org/10.5194/acp-24-3529-2024, https://doi.org/10.5194/acp-24-3529-2024, 2024
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Using idealized large eddy simulations, we find that clouds forming in the Arctic in environments with low concentrations of aerosol particles may be sustained by mixing in new particles through the cloud top. Observations show that higher concentrations of these particles regularly exist above cloud top in concentrations that are sufficient to promote this sustenance.
Adam C. Varble, Adele L. Igel, Hugh Morrison, Wojciech W. Grabowski, and Zachary J. Lebo
Atmos. Chem. Phys., 23, 13791–13808, https://doi.org/10.5194/acp-23-13791-2023, https://doi.org/10.5194/acp-23-13791-2023, 2023
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As atmospheric particles called aerosols increase in number, the number of droplets in clouds tends to increase, which has been theorized to increase storm intensity. We critically evaluate the evidence for this theory, showing that flaws and limitations of previous studies coupled with unaddressed cloud process complexities draw it into question. We provide recommendations for future observations and modeling to overcome current uncertainties.
Lucas J. Sterzinger, Joseph Sedlar, Heather Guy, Ryan R. Neely III, and Adele L. Igel
Atmos. Chem. Phys., 22, 8973–8988, https://doi.org/10.5194/acp-22-8973-2022, https://doi.org/10.5194/acp-22-8973-2022, 2022
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Aerosol particles are required for cloud droplets to form, and the Arctic atmosphere often has much fewer aerosols than at lower latitudes. In this study, we investigate whether aerosol concentrations can drop so low as to no longer support a cloud. We use observations to initialize idealized model simulations to investigate a worst-case scenario where all aerosol is removed from the environment instantaneously. We find that this mechanism is possible in two cases and is unlikely in the third.
Ian Boutle, Wayne Angevine, Jian-Wen Bao, Thierry Bergot, Ritthik Bhattacharya, Andreas Bott, Leo Ducongé, Richard Forbes, Tobias Goecke, Evelyn Grell, Adrian Hill, Adele L. Igel, Innocent Kudzotsa, Christine Lac, Bjorn Maronga, Sami Romakkaniemi, Juerg Schmidli, Johannes Schwenkel, Gert-Jan Steeneveld, and Benoît Vié
Atmos. Chem. Phys., 22, 319–333, https://doi.org/10.5194/acp-22-319-2022, https://doi.org/10.5194/acp-22-319-2022, 2022
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Fog forecasting is one of the biggest problems for numerical weather prediction. By comparing many models used for fog forecasting with others used for fog research, we hoped to help guide forecast improvements. We show some key processes that, if improved, will help improve fog forecasting, such as how water is deposited on the ground. We also showed that research models were not themselves a suitable baseline for comparison, and we discuss what future observations are required to improve them.
Joseph Sedlar, Adele Igel, and Hagen Telg
Atmos. Chem. Phys., 21, 4149–4167, https://doi.org/10.5194/acp-21-4149-2021, https://doi.org/10.5194/acp-21-4149-2021, 2021
Ines Bulatovic, Adele L. Igel, Caroline Leck, Jost Heintzenberg, Ilona Riipinen, and Annica M. L. Ekman
Atmos. Chem. Phys., 21, 3871–3897, https://doi.org/10.5194/acp-21-3871-2021, https://doi.org/10.5194/acp-21-3871-2021, 2021
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We use detailed numerical modelling to show that small aerosol particles (diameters ~25–80 nm; so-called Aitken mode particles) significantly influence low-level cloud properties in the clean summertime high Arctic. The small particles can help sustain clouds when the concentration of larger particles is low (<10–20 cm-3). Measurements from four different observational campaigns in the high Arctic support the modelling results as they indicate that Aitken mode aerosols are frequently activated.
Cited articles
Ackerman, A. S., Kirkpatrick, M. P., Stevens, D. E., and Toon, O. B.: The impact of humidity above stratiform clouds on indirect aerosol climate forcing, Nature, 432, 1014–1017, 2004. a
Anderson, J. B.: Observations from airplanes of cloud and fog conditions along the southern California coast, Mon. Weather Rev., 59, 264–270, 1931. a
Bott, A. and Trautmann, T.: PAFOG—A new efficient forecast model of radiation fog and low-level stratiform clouds, Atmos. Res., 64, 191–203, 2002. a
Bott, A., Sievers, U., and Zdunkowski, W.: A radiation fog model with a detailed treatment of the interaction between radiative transfer and fog microphysics, J. Atmos. Sci., 47, 2153–2166, 1990. a
Bott, A., Trautmann, T., and Zdunkowski, W.: A numerical model of the cloud-topped planetary boundary-layer: Radiation, turbulence and spectral microphysics in marine stratus, Q. J. Roy. Meteor. Soc., 122, 635–667, 1996. a
Boutle, I., Price, J., Kudzotsa, I., Kokkola, H., and Romakkaniemi, S.: Aerosol–fog interaction and the transition to well-mixed radiation fog, Atmos. Chem. Phys., 18, 7827–7840, https://doi.org/10.5194/acp-18-7827-2018, 2018. a
Boutle, I., Angevine, W., Bao, J.-W., Bergot, T., Bhattacharya, R., Bott, A., Ducongé, L., Forbes, R., Goecke, T., Grell, E., Hill, A., Igel, A. L., Kudzotsa, I., Lac, C., Maronga, B., Romakkaniemi, S., Schmidli, J., Schwenkel, J., Steeneveld, G.-J., and Vié, B.: Demistify: a large-eddy simulation (LES) and single-column model (SCM) intercomparison of radiation fog, Atmos. Chem. Phys., 22, 319–333, https://doi.org/10.5194/acp-22-319-2022, 2022. a, b
Bretherton, C., Blossey, P. N., and Uchida, J.: Cloud droplet sedimentation, entrainment efficiency, and subtropical stratocumulus albedo, Geophys. Res. Lett., 34, L03813, https://doi.org/10.1029/2006GL027648, 2007. a
Chen, C., Zhang, M., Perrie, W., Chang, R., Gultepe, I., Fernando, H. J., and Chen, X.: A Case Study: Evaluation of PAFOG One-D Model With Advection in Simulations of Fog/Stratus From C-FOG Experiment, J. Geophys. Res.-Atmos., 126, e2021JD034812, https://doi.org/10.1029/2021JD034812, 2021. a, b
Dorman, C. E., Grachev, A. A., Gultepe, I., and Fernando, H. J.: Toward Improving Coastal-Fog Prediction (C-FOG), Bound.-Lay. Meteorol., 181, 167–170, https://doi.org/10.1007/s10546-021-00664-8, 2021. a
Dupont, J.-C., Haeffelin, M., Protat, A., Bouniol, D., Boyouk, N., and Morille, Y.: Stratus–fog formation and dissipation: a 6-day case study, Bound.-Lay. Meteorol., 143, 207–225, 2012. a
Duynkerke, P. G.: Turbulence, radiation and fog in Dutch stable boundary layers, Bound.-Lay. Meteorol., 90, 447–477, 1999. a
Fernando, H. J., Gultepe, I., Dorman, C., Pardyjak, E., Wang, Q., Hoch, S., Richter, D., Creegan, E., Gaberšek, S., Bullock, T., Hocut, C., Chang, R., Alappattu, D., Dimitrova, R., Flagg, D., Grachev, A., Krishnamurthy, R., Singh, D. K., Lozovatsky, I., Nagare, B., Sharma, A., Wagh, S., Wainwright, C., Wroblewski, M., Yamaguchi, R., Bardoel, S., Coppersmith, R. S., Chisholm, N., Gonzalez, E., Gunawardena, N., Hyde, O., Morrison, T., Olson, A., Perelet, A., Perrie, W., Wang, S., and Wauer, B.: C-FOG: life of coastal fog, B. Am. Meteorol. Soc., 102, E244–E272, 2021. a
Fitzgerald, J. W.: Marine aerosols: A review, Atmos. Environ. A-Gen., 25, 533–545, 1991. a
Gultepe, I. (Ed.) and Milbrandt, J.: Microphysical observations and mesoscale model simulation of a warm fog case during FRAM project, in: Fog and boundary layer clouds: Fog visibility and forecasting, Springer, 1161–1178, https://doi.org/10.1007/978-3-7643-8419-7_4, 2007. a, b
Gultepe, I., Isaac, G., Leaitch, W., and Banic, C.: Parameterizations of marine stratus microphysics based on in situ observations: Implications for GCMs, J. Climate, 9, 345–357, 1996. a
Haeffelin, M., Bergot, T., Elias, T., Tardif, R., Carrer, D., Chazette, P., Colomb, M., Drobinski, P., Dupont, E., Dupont, J.-C., Gomes, L., Musson-Genon, L., Pietras, C., Plana-Fattori, A., Protat, A., Rangognio, J., Raut, J.-C., Rémy, S., Richard, D., Sciare, J., and Zhang, X.: PARISFOG: Shedding new light on fog physical processes, B. Am. Meteorol. Soc., 91, 767–783, 2010. a, b, c
Hill, A., Dobbie, S., and Yin, Y.: The impact of aerosols on non-precipitating marine stratocumulus. I: Model description and prediction of the indirect effect, Q. J. Roy. Meteor. Soc. 134, 1143–1154, 2008. a
Igel, A. L.: Processes Controlling the Entrainment and Liquid Water Response to Aerosol Perturbations in Non-Precipitating Stratocumulus Clouds, J. Atmos. Sci., 81, 1605–1616, 2024. a
Kim, W., Yum, S. S., Hong, J., and Song, J. I.: Improvement of fog simulation by the nudging of meteorological tower data in the WRF and PAFOG coupled model, Atmosphere, 11, 311, https://doi.org/10.3390/atmos11030311, 2020a. a, b
Koračin, D.: Modeling and forecasting marine fog, in: Marine fog: challenges and advancements in observations, modeling, and forecasting, edited by: Koračin, D. and Dorman, C. E., Springer, 425–475, https://doi.org/10.1007/978-3-319-45229-6, 2017. a, b, c
Koračin, D. and Dorman, C. E.: Marine atmospheric boundary layer divergence and clouds along California in June 1996, Mon. Weather Rev., 129, 2040–2056, 2001. a
Lewis, J., Koracin, D., Rabin, R., and Businger, J.: Sea fog off the California coast: Viewed in the context of transient weather systems, J. Geophys. Res.-Atmos., 108, 4457, https://doi.org/10.1029/2002JD002833, 2003. a, b
Mccumber, M. C. and Pielke, R. A.: Simulation of the effects of surface fluxes of heat and moisture in a mesoscale numerical model: 1. Soil layer, J. Geophys. Res.-Oceans, 86, 9929–9938, 1981. a
Mellor, G. L. and Yamada, T.: A hierarchy of turbulence closure models for planetary boundary layers, J. Atmos. Sci., 31, 1791–1806, 1974. a
Mellor, G. L. and Yamada, T.: Development of a turbulence closure model for geophysical fluid problems, Rev. Geophys., 20, 851–875, 1982. a
Pope, N. and Igel, A.: Processed model output in support of Pope and Igel 2025, Zenodo [code/data set], https://doi.org/10.5281/zenodo.15475331, 2025. a, b
Stolaki, S., Haeffelin, M., Lac, C., Dupont, J.-C., Elias, T., and Masson, V.: Influence of aerosols on the life cycle of a radiation fog event. A numerical and observational study, Atmos. Res., 151, 146–161, 2015. a
Tardif, R. and Rasmussen, R. M.: Evaporation of nonequilibrium raindrops as a fog formation mechanism, J. Atmos. Sci., 67, 345–364, 2010. a
Wang, S., Wang, Q., and Feingold, G.: Turbulence, condensation, and liquid water transport in numerically simulated nonprecipitating stratocumulus clouds, J. Atmos. Sci., 60, 262–278, 2003. a
Williams, A. S. and Igel, A. L.: Cloud top radiative cooling rate drives non-precipitating stratiform cloud responses to aerosol concentration, Geophys. Res. Lett., 48, e2021GL094740, https://doi.org/10.1029/2021GL094740, 2021. a
Wood, R. and Bretherton, C. S.: Boundary layer depth, entrainment, and decoupling in the cloud-capped subtropical and tropical marine boundary layer, J. Climate, 17, 3576–3588, 2004. a
Zhao, L., Niu, S., Zhang, Y., and Xu, F.: Microphysical characteristics of sea fog over the east coast of Leizhou Peninsula, China, Adv. Atmos. Sci., 30, 1154–1172, 2013. a
Short summary
We used an atmospheric model that simulates a single column to study the sensitivity of marine fog formed through the lowering of the base of a stratus cloud to meteorology and aerosols. We found that higher aerosol concentration reduces the likelihood and duration of fog but leads to denser fog. This overall trend was caused by multiple physical mechanisms depending on conditions.
We used an atmospheric model that simulates a single column to study the sensitivity of marine...
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