Coalescence Enhancement in large Multicell Storms Caused by the Emissions from a Kraft Paper Mill

Mather, Graeme K.

doi:10.1175/1520-0450(1991)030<1134:ceilms>2.0.co;2

Cited by 42 publications

(30 citation statements)

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“…For example, clouds downwind of particulate sources produce more rain than other storms, as has been reported by Mather (1991). To study the effect of urban particulate matter on CG lightning activity, the annual averages of PM 10 and SO 2 concentrations have been considered in relation to the percent change in CG flashes.…”

Section: Resultsmentioning

confidence: 99%

Characteristics of cloud-to-ground lightning activity over Seoul, South Korea in relation to an urban effect

Kar

Liou

2007

Ann. Geophys.

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Abstract. Cloud-to-ground (CG) lightning flash data collected by the lightning detection network installed at the Korean Meteorological Administration (KMA) have been used to study the urban effect on lightning activity over and around Seoul, the largest metropolitan city of South Korea, for the period of 1989-1999. Negative and positive flash density and the percentage of positive flashes have been calculated. Calculation reveals that an enhancement of approximately 60% and 42% are observed, respectively, for negative and positive flash density over and downwind of the city. The percentage decrease of positive flashes occurs over and downwind of Seoul and the amount of decrease is nearly 20% compared to upwind values. The results are in good agreement with those obtained by and Westcott (1995). CG lightning activities have also been considered in relation to annual averages of PM 10 (particulate matter with an aerodynamic diameter smaller than 10 µm) and sulphur dioxide (SO 2 ) concentrations. Interesting results are found, indicating that the higher concentration of SO 2 contributes to the enhancement of CG lightning flashes. On the other hand, the contribution from PM 10 concentration has not appeared in this study to be as significant as SO 2 in the enhancement of CG lightning flashes. Correlation coefficients of 0.33 and 0.64 are found between the change in CG lightning flashes and the PM 10 and SO 2 , respectively, for upwind to downwind areas, suggesting a significant influence of the increased concentration of SO 2 on the enhancement of CG flashes.

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Section: Resultsmentioning

confidence: 99%

Characteristics of cloud-to-ground lightning activity over Seoul, South Korea in relation to an urban effect

Kar

Liou

2007

Ann. Geophys.

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“…Results from METROMEX indicated that summer precipitation was typically enhanced by 5%-25% over background values within 50-75 km downwind of the urban region (Huff and Vogel 1978;Changnon 1979;Braham et al 1981, Changnon et al 1981, 1991. More recent observations in several cities show an increasing thunderstorm frequency associated with increased population growth within these cities (Balling and Brazel 1987;Jaurequi and Romales 1996).…”

Section: Introductionmentioning

confidence: 99%

“…Enhanced CCN concentrations can suppress warm-rain processes by producing a narrower droplet spectrum that inhibits collision and coalescence processes (e.g., Warner and Twomey 1967;Warner 1968;Rosenfeld 1999). On the other hand, some urban areas, like St. Louis, can also be sources of GCCN, or ultragiant particles, that can enhance warm-rain processes (Johnson 1976;Hindman et al 1977a,b;Mather 1991;Cooper et al 1997;Reisin et al 1996;Feingold et al 1999;Yin et al 2000) and thus increase surface precipitation around urban regions.…”

Section: Introductionmentioning

confidence: 99%

Urban Aerosol Impacts on Downwind Convective Storms

Heever

Cotton

2007

Journal of Applied Meteorology and Climatology

290

140

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The impacts of urban-enhanced aerosol concentrations on convective storm development and precipitation over and downwind of St. Louis, Missouri, are investigated. This is achieved through the use of a cloud-resolving mesoscale model, in which sophisticated land use processes and aerosol microphysics are both incorporated. The results indicate that urban-forced convergence downwind of the city, rather than the presence of greater aerosol concentrations, determines whether storms actually develop in the downwind region. Once convection is initiated, urban-enhanced aerosols can exert a significant effect on the dynamics, microphysics, and precipitation produced by these storms. The model results indicate, however, that the response to urban-enhanced aerosol depends on the background concentrations of aerosols; a weaker response occurs with increasing background aerosol concentrations. The effects of aerosols influence the rate and amount of liquid water and ice produced within these storms, the accumulated surface precipitation, the strength and timing of the updrafts and downdrafts, the longevity of the updrafts, and the strength and influence of the cold pool. Complex, nonlinear relationships and feedbacks between the microphysics and storm dynamics exist, making it difficult to make definitive statements about the effects of urbanenhanced aerosols on downwind precipitation and convection. Because the impacts of urban aerosol on downwind storms decrease with increasing background aerosol concentrations, generalization of these results depends on the unique character of background aerosol for each urban area. For urban centers in coastal areas where background aerosol concentrations may be very low, it is speculated that urban aerosol can have very large influences on convective storm dynamics, microphysics, and precipitation.

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“…Hobbs et al (1970) and Hindman et al (1977a, b) reported that the addition of small concentrations of large CCN into warm clouds lead to the appearance of large drops and possibly to enhanced precipitation. Mather (1991) observed the appearance of large drops in the mixed phase clouds forming above the plume of a paper mill. This led him to propose that hygroscopic seeding could be an effective way to enhance precipitation.…”

Section: Introductionmentioning

confidence: 99%

The effects of aerosols on precipitation and dimensions of subtropical clouds: a sensitivity study using a numerical cloud model

2006

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Abstract. Numerical experiments were carried out using the Tel-Aviv University 2-D cloud model to investigate the effects of increased concentrations of Cloud Condensation Nuclei (CCN), giant CCN (GCCN) and Ice Nuclei (IN) on the development of precipitation and cloud structure in mixedphase sub-tropical convective clouds. In order to differentiate between the contribution of the aerosols and the meteorology, all simulations were conducted with the same meteorological conditions.The results show that under the same meteorological conditions, polluted clouds (with high CCN concentrations) produce less precipitation than clean clouds (with low CCN concentrations), the initiation of precipitation is delayed and the lifetimes of the clouds are longer. GCCN enhance the total precipitation on the ground in polluted clouds but they have no noticeable effect on cleaner clouds. The increased rainfall due to GCCN is mainly a result of the increased graupel mass in the cloud, but it only partially offsets the decrease in rainfall due to pollution (increased CCN). The addition of more effective IN, such as mineral dust particles, reduces the total amount of precipitation on the ground. This reduction is more pronounced in clean clouds than in polluted ones.Polluted clouds reach higher altitudes and are wider than clean clouds and both produce wider clouds (anvils) when more IN are introduced. Since under the same vertical sounding the polluted clouds produce less rain, more water vapor is left aloft after the rain stops. In our simulations about 3.5 times more water evaporates after the rain stops from the polluted cloud as compared to the clean cloud. The implication is that much more water vapor is transported from lower levels to the mid troposphere under polluted conditions, something that should be considered in climate models.

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Coalescence Enhancement in large Multicell Storms Caused by the Emissions from a Kraft Paper Mill

Cited by 42 publications

References 0 publications

Characteristics of cloud-to-ground lightning activity over Seoul, South Korea in relation to an urban effect

Characteristics of cloud-to-ground lightning activity over Seoul, South Korea in relation to an urban effect

Urban Aerosol Impacts on Downwind Convective Storms

The effects of aerosols on precipitation and dimensions of subtropical clouds: a sensitivity study using a numerical cloud model

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