A Comparative Study of Radiation Fog and Quasi-Fog Formation Processes During the ParisFog Field Experiment 2007
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Fog is an atmospheric phenomenon that has important environmental consequences related to visibility, air quality and climate change on local and regional scales. The formation of radiation fog results from a complex balance between surface radiative cooling, turbulent mixing in the surface layer, aerosol growth by deliquescence and activation of fog droplets. During the ParisFog field experiment, out of 16 events forecasted for radiation fog, activated fog materialized in seven events, while in five other events the visibility dropped to 1–2 km but haze particle size remained below the critical size of activation. To better understand the conditions that lead to or do not lead to sustained fog droplet activation, we performed a comparative study of dynamic, thermal, radiative and microphysical processes occurring between sunset and fog (or quasi-fog) onset. We selected two radiation fog events and two quasi-radiation fog events that occurred under similar large-scale conditions for this comparative study. We identified that aerosol growth by deliquescence and droplet activation actually occurred in both quasi-fog events, but only during <1 h. Based on ParisFog measurements, we found that the main factors limiting sustained activation of droplets at fog onset in the Paris metropolitan area are (1) lack of mixing in the surface layer (typically wind speed <0.5 ms−1), (2) relative humidity exceeding 90 % throughout the residual layer, (3) low cooling rate in the surface layer (typically less than −1 °C per hour on average) due to weak radiative cooling (0 to −30 Wm−2) and near zero sensible heat fluxes, and (4) a combination of the three factors listed above during the critical phase of droplet activation preventing the transfer of cooling from the surface to the liquid layer. In addition, we found some evidence of contrasted aerosol growth by deliquescence under high relative humidity conditions in the four events, possibly associated with the chemical nature of the aerosols, which could be another factor impacting droplet activation.
KeywordsFog haze aerosol activation radiative cooling turbulence
The authors would like to acknowledge Météo-France, Institut National des Sciences de l’Univers du Centre National de la Recherche Scientifique, Ecole Polytechnique and Air Parif for providing the measurements used in this study and the support to the ParisFog program. The authors are indebted to the many volunteers who carried out the measurements during the ParisFog field campaign. The authors would like to pay tribute to their colleague Laurent Gomes, a scientist from the Centre National de Recherches Météorologiques, who passed away unexpectedly in 2012. The ParisFog research program could not have been initiated without his leadership and enthusiasm.
- Acevedo, Otávio C., David R. Fitzjarrald (2001), The Early Evening Surface-Layer Transition: Temporal and Spatial Variability. J. Atmos. Sci., 58, 2650–2667.Google Scholar
- American-Meteorological-Society (2000), “Online Glossary of Meteorology, 2nd Ed ition.” Accessible at http://amsglossary.allenpress.com.
- Colette A.; L. Menut; M. Haeffelin; Y. Morille (2008), Impact of the Long Range Transport of Aerosols on the Air Quality in the Paris Area; Atmos. Env., Vol 42, 390–402.Google Scholar
- Dupont J.-C., M. Haeffelin , A. Protat, D. Bouniol, N. Boyouk, Y. Morille (2012), Stratus fog formation and dissipation. A 6-day case study. Boundary-Layer Meteorol 143:207–225.Google Scholar
- Dabas, A., S. Remy, and T. Bergot (2011), Use of a Sodar to Improve the Forecast of Fogs and Low Clouds on Airports. Pure Appl. Geophys., 169, 769–781.Google Scholar
- Elias, T., M. Haeffelin, P. Drobinski, L. Gomes, J. Rangognio, T. Bergot, P. Chazette, J.-C. Raut, M. Colomb, (2009): Particulate contribution to extinction of visible radiation:pollution, haze, and fog. Atmospheric Research 92, 443–454.Google Scholar
- Gultepe, I., Pearson, G., Milbrandt, J. A., Hansen, B., Platnick, S., Taylor, P., Gordon, M., Oakley, J. P., and Cober, S. (2009), the Fog Remote Sensing and Modeling Field Project, Bulletin of the American Meteorological Society 90, 341–359.Google Scholar
- Gultepe, I., R. Tardif, S. C. Michaelides, J. Cermak, A. Bott, J. Bendix, M. D. Müller, M. Pagowski, B. K. Hansen, G. P. Ellrod, W. Jacobs, G. Toth, and S. Cober, (2007), Fog research: A review of past achievements and future perspectives. Pure Appl. Geophys., 164, 1121–1159.Google Scholar
- Haeffelin, M., F. Angelini, Y. Morille, G. Martucci, S. Frey, G.-P. Gobbi, S. Lolli, C. D. O’Dowd, L. Sauvage, I. Xueref-Rémy, B. Wastine, D. Feist, (2012): Evaluation of mixing height retrievals from automatic profiling lidars and ceilometers in view of future integrated networks in Europe, Boundary-Layer Meteorol (2012) 143:49–75 doi: 10.1007/s10546-011-9643-z.
- Haeffelin, M., T. Bergot, T. Elias, R. Tardif, D. Carrer, P. Chazette, M. Colomb, P. Drobinski, E. Dupont, J-C. Dupont, L. Gomes, L. Musson-Genon, C. Pietras, A. Plana-Fattori, A. Protat, J. Rangognio, J-C. Raut, S. Rémy, D. Richard, J. Sciare, X. Zhang (2010), PARISFOG: Shedding New Light on Fog Physical Processes. Bull. Amer. Meteor. Soc., 91, 767–783. doi: 10.1175/2009BAMS2671.1.
- Haeffelin, M., L. Barthès, O. Bock, C. Boitel, S. Bony, D. Bouniol, H. Chepfer, M. Chiriaco, J. Cuesta, J. Delanoë, P. Drobinski, J-L. Dufresne, C. Flamant, M. Grall, A. Hodzic, F. Hourdin, F. Lapouge, Y. Lemaître, A. Mathieu, Y. Morille, C. Naud, V. Noël, B. O’Hirok, J. Pelon, C. Pietras, A. Protat, B. Romand, G. Scialom, R. Vautard (2005), SIRTA, a ground-based atmospheric observatory for cloud and aerosol research.” Annales Geophysicae, 23, pp 253–275.Google Scholar
- Kokkola, H., S. Romakkaniemi, and A. Laaksonen (2003), On the formation of radiation fogs under heavily polluted conditions. Atmos. Chem. Phys. 3:581–589.Google Scholar
- Liu D. Y., S. J. Niu, J. Yang, L. J. Zhao, J. J. Lu, and C. S. Ls. J. Niu, L. J. Zhao, and C. S. Lu (2011), Summary of a 4-Year Fog Field Study in Northern Nanjing, Part 1: Fog Boundary Layer. Pure Appl. Geophys., 169, 809–819.Google Scholar
- Miao Y., R. Potts, X. Huang, G. Elliott, and R. Rivett (2011), A Fuzzy Logic Fog Forecasting Model for Perth Airport. Pure Appl. Geophys., 169, 1107–1119.Google Scholar
- Morille, Y., M. Haeffelin, P. Drobinski, J. Pelon (2007), STRAT: An Automated Algorithm to Retrieve the Vertical Structure of the Atmosphere from Single-Channel Lidar Data. J. Atmos. Oceanic Technol., 24, 761–775. http://dx.doi.org/10.1175/JTECH2008.1.
- Price, J. (2011), Radiation Fog. Part I: Observations of Stability and Drop Size Distributions. Boundary Layer Meteorol, 139:167–191Google Scholar
- Stolaki S., I. Pytharoulis, and T. Karacostas (2011), A Study of Fog Characteristics Using a Coupled WRF–COBEL Model Over Thessaloniki Airport, Greece. Pure Appl. Geophys. 169, 961–981.Google Scholar
- Tardif, Robert, Roy M. Rasmussen (2007), Event-Based Climatology and Typology of Fog in the New York City Region. J. Appl. Meteor. Climatol., 46, 1141–1168. http://dx.doi.org/10.1175/JAM2516.1
- Tsyro, S. G.: To what extent can aerosol water explain the discrepancy between model calculated and gravimetric PM 10 and PM 2.5 ?, Atmos. Chem. Phys., 5, 515–532, doi: 10.5194/acp-5-515-2005, 2005.
- Van der Velde IR, Steeneveld GJ, Wichers Schreur BGJ, Holtslag AAM (2010), Modeling and forecasting the onset and duration of severe radiation fog under frost conditions. Mon Wea Rev 138(11):4237–4253Google Scholar