Cloud Condensation Nuclei from a Paper Mill. Part II: Calculated Effects on Rainfall

Hindman, Edward E.; Tag, Paul M.; Silverman, Bernard A.

doi:10.1175/1520-0450(1977)016<0753:ccnfap>2.0.co;2

Cited by 22 publications

(10 citation statements)

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“…Hobbs et al (1970), on the other hand, observed increases in precipitation downwind of paper mills in Washington State. Although the presence of giant CCN was thought to be responsible for the observed increases, Hindman et al (1977) concluded that giant CCN by themselves could not fully account for the observations and that other factors related to the environmental meteorological parameters are the dominant factors.…”

Section: Introductionmentioning

confidence: 99%

Temporal rainfall fluctuations in Israel and their possible link to urban and air pollution effects

Halfon

Levin

Alpert

2009

Environ. Res. Lett.

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In this paper we analyze spatial variations of the annual rainfall that have taken place in the non-arid regions of Israel (annual rainfall > 200 mm) during the years 1952-2006, incorporating all available data. The results of the present study over the research area as a whole indicate that no significant temporal change of the annual rainfall occurred in any region of the study area. However, focusing on spatial rainfall fluctuations between sub-regions in the study area, a significant increase was observed between the stations located downwind and those upwind of the Greater Tel Aviv region.This increase supports previous reports showing that rainfall enhancement is observed downwind (and close) to urban centers. In contrast to a few previous reports, no decrease in the ratio between the mountain precipitation to that over the coastal region was found. Over the period of the present study, the rainfall ratio between the upwind slopes and the seashore remained unchanged, with a slight increase in the central part of the country.The only hilly place where a slight decrease in annual rainfall was observed is the lee side (eastern slopes) of the Galilee Mountains. This result is important because the eastern slopes of the Galilee Mountains have for years been part of the target area for Israeli artificial cloud seeding for rain enhancement. The results therefore suggest that unless there was a pronounced change in the synoptic conditions during rain spells, seeding in Israel had no positive effect on rainfall amounts.

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Section: Introductionmentioning

confidence: 99%

Temporal rainfall fluctuations in Israel and their possible link to urban and air pollution effects

Halfon

Levin

Alpert

2009

Environ. Res. Lett.

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“…Thereafter, any further growth occurs by the collision and coalescence of droplets (e.g., Wallace and Hobbs 1977). Relatively large droplets are more likely to form in clouds with low CCN concentrations (Squires 1958;Hindman et al 1977a;Albrecht 1989). Gerber (1996) investigated the occurrence of drizzle as a function of effective droplet radius for a variety of marine stratus clouds and described a so-called drizzle threshold with an effective radius of about 15 m. Stratus clouds with effective radii below this threshold generally did not produce significant drizzle.…”

Section: Introductionmentioning

confidence: 99%

Drizzle Suppression in Ship Tracks

Ferek¹,

Garrett²,

Hobbs³

et al. 2000

J. Atmos. Sci.

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103

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Although drizzle was a relatively infrequent occurrence during the Monterey Area Ship Track study, diverse measurements from several sources produced data signals consistent with a reduction in drizzle drops in stratus clouds affected by ship effluents. Concurrent increases in liquid water in the cloud droplet size range, due to redistribution from the drizzle mode, were not always observed, possibly because of the relatively small and often negligible amounts of water in the drizzle mode. Significant changes in cloud droplet size distribution, as well as reductions in drizzle flux and concentrations of drops 50-m radius, were observed in ship tracks when drizzle was more uniformly present in the ambient cloud. Radiometric measurements showed that increased droplet concentrations in ship tracks, which resulted in reduced droplet sizes, can significantly alter the liquid water path. Radar observations indicated that the reduced reflectivities of ship tracks compared with ambient clouds may be due to reductions in the concentrations of larger drops and/or reductions in the sizes of these drops. Two independent modeling studies showed decreases in drizzle in ship tracks due to the presence of smaller cloud droplets that reduced the efficiency of drop growth by collisions.

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“…Rosenfeld [94] noted suppression of rain due to forest fires in Indonesia via satellite observations, whereas Lin et al [95] highlighted increasing rainfall trend associated with elevated aerosol layers during the biomass burning season in Amazonia. Jirak and Cotton [96] reported decrease in precipitation during the past half-century at downwind directions of Denver and Colorado Springs, contrary to other studies [97][98][99] that found increasing rainfall downwind of major urban areas possibly due to giant CCN from paper mills exhausts. On the other hand, Warner [100] by analyzing longterm ground measurements showed no evidence of subsequent changes in surface precipitation results that agree with those of Woodcock and Jones [101] over Hawaii.…”

Section: Discussionmentioning

confidence: 80%

Long-Term (1951–2007) Rainfall Trends around Six Indian Cities: Current State, Meteorological, and Urban Dynamics

Kharol

Kaskaoutis

Sharma

et al. 2013

Advances in Meteorology

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The present study focuses on analyzing the precipitation trends over six Indian cities during the summer monsoon (June–September) covering the period 1951–2007 and also attempting to investigate possible urban forcing and dynamics by examining the variation in precipitation in the upwind and downwind directions. The analysis shows negative trends in the total number of rainy days over Hyderabad (−10.4%), Kanpur (−7.1%), Jaipur (−10.5%), and Nagpur (−4.8%) and positive trends over Delhi (7.4%) and Bangalore (22.9%). On the other hand, decreases of −21.3%, −5.9%, −14.2%, and −14.6% in seasonal rainfall are found over Delhi, Hyderabad, Jaipur, and Kanpur, respectively, whereas Bangalore and Nagpur show 65.8% and 13.5% increase. The lesser rainfall and rainy days, along with the mostly declining trend, in the downwind directions of the cities may imply an urban influence in precipitation associated with the increased anthropogenic emissions due to expansion of the urban areas and the increase of population. However, the large spatiotemporal variability of precipitation and the lack of statistical significance in the vast majority of the trends do not allow the extraction of safe conclusion concerning the aerosol-precipitation interactions around Indian cities.

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Cloud Condensation Nuclei from a Paper Mill. Part II: Calculated Effects on Rainfall

Cited by 22 publications

References 0 publications

Temporal rainfall fluctuations in Israel and their possible link to urban and air pollution effects

Temporal rainfall fluctuations in Israel and their possible link to urban and air pollution effects

Drizzle Suppression in Ship Tracks

Long-Term (1951–2007) Rainfall Trends around Six Indian Cities: Current State, Meteorological, and Urban Dynamics

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