Abstract
On the afternoon of 3 July 2004 in Hyytiälä (Juupajoki, Finland), convective cells produced a strong downburst causing forest damage. The SMEAR II field station, situated near the damage site, enabled a unique micrometeorological analysis of a microburst with differences above and inside the canopy. At the time of the event, a squall line associated with a cold front was crossing Hyytiälä with a reflectivity maximum in the middle of the squall line. A bow echo, rear-inflow notch, and probable mesovortex were observed in radar data. The bow echo moved west-north-west, and its apex travelled just north of Hyytiälä. The turbulence data were analysed at two locations above the forest canopy and at one location at sub-canopy. At 1412 EET (Eastern European Time, UTC+2), the horizontal and vertical wind speed increased and the wind veered, reflecting the arrival of a gust front. At the same time, the carbon dioxide concentration increased due to turbulent mixing, the temperature decreased due to cold air flow from aloft and aerosol particle concentration decreased due to rain scavenging. An increase in the number concentration of ultra-fine particles (< 10 nm) was detected, supporting the new particle formation either from cloud outflow or due to rain. Five minutes after the gust front (1417 EET), strong horizontal and downward vertical wind speed gusts occurred with maxima of 22 and 15 m s−1, respectively, reflecting the microburst. The turbulence spectra before, during and after the event were consistent with traditional turbulence spectral theory.
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Aalto P, Hämeri K, Becker E, Weber R, Salm J, Mäkelä JM, Hoell C, O’Dowd C, Karlsson H, Hansson H-C, Väkevä M, Koponen I, Buzorius G and Kulmala M (2001). Physical characterization of aerosol particles during nucleation events. Tellus 53B: 344–358
Atkins NT and Wakimoto RM (1991). Wet microburst activity over the southeastern United States: implications for forecasting. Wea Forecast 6: 470–482
Atkins NT, Arnott JM, Przybylinski RW, Wolf RA and Ketcham BD (2004). Vortex structure and evolution within bow echoes. Part I: Single-doppler and damage analysis of the 29 June 1998 derecho. Mon Wea Rev 132: 2224–2242
Atkins NT, Bouchard CS, Przybylinski RW, Trapp RJ and Schmocker G (2005). Damaging surface wind mechanisms within the 10 June 2003 Saint Louis bow echo during BAMEX. Mon Wea Rev 133: 2275–2296
Charba J (1974). Application of gravity current model to analysis of squall-line gust front. Mon Wea Rev 102: 140–156
Choi ECC (2004). Field measurement and experimental study of wind speed profile during thunderstorms. J Wind Eng Ind Aerodyn 92: 275–290
Clarke AD, Varner JL, Eisele F, Mauldin RL, Tanner D and Litchy M (1998). Particle production in the remote marine atmosphere: cloud outflow and subsidence during ACE 1. J Geophys Res 103: 16397–16409
Droegemeier KK and Wilhelmson RB (1987). Numerical simulation of thunderstorm outflow dynamics. Part I: Outflow sensitivity experiments and turbulence dynamics. J Atmos Sci 44: 1180–1210
Evans JS and Doswell CA III (2001). Examination of derecho environments using proximity soundings. Wea Forecast 16: 329–342
Fujita TT (1979) Objectives, operation and results of project NIMROD. Preprints, 11th conference on severe local Storms, Kansas City, MO, Amer Meteorol Soc 259–266
Fujita TT (1985) The Downbursts—microburst and macroburst. SMRP researcher paper number 210, University of Chicago, Department of the Geophysical Sciences, pp 60–118
Hari P and Kulmala M (2005). Station for measuring ecosystem–atmosphere relations (SMEAR II). Boreal Env Res 10: 315–322
Hirsikko A, Bergman T, Laakso L, Dal~Maso M, Riipinen I, Hõrrak U and Kulmala M (2007). Identification and classification of the formation of intermediate ions measured in boreal forest. Atmos Chem Phys 7: 201–210
Hjelmfelt MR, Orville HD, Roberts RD, Chen JP and Kopp FJ (1989). Observational and numerical study of a microburst line-producing storm. J Atmos Sci 46: 2731–2744
Holton JR (1992). A introduction to dynamic meteorology, 4th edn. Academic Press, San Diego, California, 120–122
Kaimal JC and Kristensen L (1991). Time series tapering for short data samples. Boundary-Layer Meteorol 57: 187–194
Kaimal JC and Finnigan JJ (1994). Atmospheric boundary layer flows. Oxford University Press, New York, USA, 234–240
Keil A and Wendisch M (2001). Bursts of Aitken mode and ultrafine particles observed at the top of continental boundary layer clouds. J Aerosol Sci 32: 649–660
Laakso L, Hirsikko A, Grönholm T, Kulmala M, Luts A and Parts T-E (2006). Waterfalls as sources of small charged aerosol particles. Atmos Chem Phys Discuss 6: 9297–9314
Mitchell KE and Hovermale JB (1977). A numerical investigation of the severe thunderstorm gust front. Mon Wea Rev 105: 657–675
Mueller CK and Carbone RE (1987). Dynamics of a thunderstorm outflow. J Atmos Sci 44: 1879–1897
Ogura Y and Liou M-T (1980). The structure of a midlatitude squall line: A case study. J Atmos Sci 37: 553–567
Ohno H, Suzuki O, Nirasawa H, Yoshizaki M, Hasegawa N, Tanaka Y, Muramatsu Y and Ogura Y (1994). Okayama downbursts on 27 June (1991) downburst identifications and environmental conditions. J Meteorol Soc Japan 72: 197–221
Parker MD and Johnson RH (2000). Organizational modes of midlatitude mesoscale convective systems. Mon Wea Rev 128: 3413–3436
Perry KD and Hobbs PV (1994). Further evidence for particle nucleation in clear air adjacent to marine cumulus clouds. J Geophys Res 99: 22803–22818
Piper M and Lundquist JK (2004). Surface layer turbulence measurements during a frontal passage. J Atmos Sci 61: 1768–1780
Proctor FH (1988). Numerical simulations of an isolated microburst. Part I: Dynamics and Structure. J Atmos Sci 45: 3137–3160
Przybylinski RW, DeCaire D (1985) Radar signatures associated with the derecho, a type of mesoscale convective system. Preprints, 14th Conference on severe local storms. Indianapolis, IN, Amer Meteorol Soc, pp 228–231
Przybylinski RW (1995). The bow echo: Observations, numerical simulations and severe weather detection methods. Wea Forecast 10: 203–218
Punkka A-J, Teittinen J and Johns RH (2006). Synoptic and mesoscale analysis of a high-latitude derecho-severe thunderstorm outbreak in Finland on 5 July 2002. Wea Forecast 21: 752–763
Sherman DJ (1987). The passage of a weak thunderstorm downburst over an instrumented tower. Mon Wea Rev 115: 1193–1205
Smull BF and Houze RA Jr. (1987). Rear inflow in squall lines with trailing stratiform precipitation. Mon Wea Rev 115: 2869–2889
Takayma H, Niino H, Watanabe S and Sugaya J (1997). Downbursts in the Northerwestern Part of Saitama Prefecture on 8 September 1994. J Meteorol Soc Japan 75: 885–905
Trapp RJ and Weisman ML (2003). Low-level mesovortices within squall lines and bow echoes. Part II: their genesis and implications. Mon Wea Rev 131: 2804–2823
Vesala T, Haataja J, Aalto P, Altimir N, Buzorius G, Garam E, Hämeri K, Ilvesniemi H, Jokinen V, Keronen P, Lahti T, Markkanen T, Mäkelä JM, Nikinmaa E, Palmroth S, Palva L, Pohja T, Pumpanen J, Rannik Ü, Siivola E, Ylitalo H, Hari P and Kulmala M (1998). Long-term field measurements of atmosphere-surface interactions in boreal forest combining forest ecology, micrometeorology, aerosol Physics and atmospheric chemistry. Trends Heat, Mass Momentum Transfer 4: 17–35
Wakimoto RM (1982). The life cycle of thunderstorm gust fronts as viewed with Doppler radar and rawinsonde data. Mon Wea Rev 110: 1060–1082
Wakimoto RM (1985). Forecasting dry microburst activity over the high plains. Mon Wea Rev 113: 1131–1143
Wakimoto RM (2001). Convectively driven high wind events. Severe Convective Storms, American Meteorological Society, Boston, MA, 255–298
Wakimoto RM, Murphey HV, Nester A, Jorgensen DP and Atkins NT (2006). High winds generated by bow echoes. Part I: Overview of the Omaha bow echo 5 July 2003 storm during BAMEX. Mon Wea Rev 134: 2793–2812
Weisman ML and Trapp RJ (2003). Low-level mesovortices within squall lines and bow echoes. Part I: Overview and dependence on environmental shear. Mon Wea Rev 131: 2779–2803
Wheatley DM, Trapp RJ and Atkins NT (2006). Radar and damage analysis of severe bow echoes observed during BAMEX. Mon Wea Rev 134: 791–806
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Järvi, L. et al. (2007). Micrometeorological observations of a microburst in southern Finland. In: Baklanov, A., Grisogono, B. (eds) Atmospheric Boundary Layers. Springer, New York, NY. https://doi.org/10.1007/978-0-387-74321-9_13
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DOI: https://doi.org/10.1007/978-0-387-74321-9_13
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