Modification of Precipitation from Warm Clouds—A Review

Cotton, William R.

doi:10.1175/1520-0477(1982)063<0146:mopfwc>2.0.co;2

Cited by 26 publications

(11 citation statements)

References 92 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…During the 1950s and '60s many aerosol-cloudprecipitation studies were done in the context of cloud seeding, i.e. the attempt to deliberately modify the microstructure of clouds with the aim of precipitation enhancement or hail suppression, topics which are still very controversial (Cotton, 1982(Cotton, , 2009Garstang et al, 2005;Levin and Cotton, 2008). Today, in the broader context of climate change, the impact of unintentional anthropogenic changes of the atmospheric aerosol and the microstructure of clouds and precipitation are probably even more important (Borys et al, 2003;Rosenfeld and Givati, 2006;Alpert et al, 2008;Levin and Cotton, 2008;Ayers and Levin, 2009).…”

Section: Introductionmentioning

confidence: 99%

Aerosol-cloud-precipitation effects over Germany as simulated by a convective-scale numerical weather prediction model

2012

View full text Add to dashboard Cite

Possible aerosol-cloud-precipitation effects over Germany are investigated using the COSMO model in a convection-permitting configuration close to the operational COSMO-DE. Aerosol effects on clouds and precipitation are modeled by using an advanced two-moment microphysical parameterization taking into account aerosol assumptions for cloud condensation nuclei (CCN) as well as ice nuclei (IN). Simulations of three summer seasons have been performed with various aerosol assumptions, and are analysed regarding surface precipitation, cloud properties, and the indirect aerosol effect on near-surface temperature. We find that the CCN and IN assumptions have a strong effect on cloud properties, like condensate amounts of cloud water, snow and rain as well as on the glaciation of the clouds, but the effects on surface precipitation are – when averaged over space and time – small. This robustness can only be understood by the combined action of microphysical and dynamical processes. On one hand, this shows that clouds can be interpreted as a buffered system where significant changes to environmental parameters, like aerosols, have little effect on the resulting surface precipitation. On the other hand, this buffering is not active for the radiative effects of clouds, and the changes in cloud properties due to aerosol perturbations may have a significant effect on radiation and near-surface temperature

show abstract

Section: Introductionmentioning

confidence: 99%

Aerosol-cloud-precipitation effects over Germany as simulated by a convective-scale numerical weather prediction model

2012

View full text Add to dashboard Cite

show abstract

“…Hygroscopic seeding to promote water droplet coalescence by introducing appropriately sized salt particles, sprayed water droplets, or saline solution into clouds has long been known and used (Bowen, 1952;Biswas and Dennis, 1971;Cotton, 1982;Murty et al, 2000). In classic hygroscopic seeding approaches, large hygroscopic particles at least 10 µm in diameter are used to provide raindrop embryos.…”

Section: Introductionmentioning

confidence: 99%

Effect of hygroscopic seeding on warm rain clouds – numerical study using a hybrid cloud microphysical model

Kuba

Murakami²

2010

Atmos. Chem. Phys.

View full text Add to dashboard Cite

Abstract. The effect of hygroscopic seeding on warm rain clouds was examined using a hybrid cloud microphysical model combining a Lagrangian Cloud Condensation Nuclei (CCN) activation model, a semi-Lagrangian droplet growth model, and an Eulerian spatial model for advection and sedimentation of droplets. This hybrid cloud microphysical model accurately estimated the effects of CCN on cloud microstructure and suggested the following conclusions for a moderate continental air mass (an air mass with a large number of background CCN). (1) Seeding can hasten the onset of surface rainfall and increase the accumulated amount of surface rainfall if the amount and radius of seeding particles are appropriate. (2) The optimal radius of monodisperse particles to increase rainfall becomes larger with the increase in the total mass of seeding particles. (3) Seeding with salt micro-powder can hasten the onset of surface rainfall and increase the accumulated amount of surface rainfall if the amount of seeding particles is sufficient. (4) Seeding by a hygroscopic flare decreases rainfall in the case of large updraft velocity (shallow convective cloud) and increases rainfall slightly in the case of small updraft velocity (stratiform cloud). (5) Seeding with hygroscopic flares including ultragiant particles (r>5 µm) hastens the onset of surface rainfall but may not significantly increase the accumulated surface rainfall amount. (6) Hygroscopic seeding increases surface rainfall by two kinds of effects: the "competition effect" by Correspondence to: N. Kuba (kuba@jamstec.go.jp) which large soluble particles prevent the activation of smaller particles and the "raindrop embryo effect" in which giant soluble particles can immediately become raindrop embryos. In some cases, one of the effects works, and in other cases, both effects work, depending on the updraft velocity and the amount and size of seeding particles.

show abstract

“…In northeastern Brazil, a semiarid region, the CHUVA project was designed to characterize warm clouds (Costa et al 2000) and the organized convection influenced by the intertropical convergence zone and easterly waves (Kouadio et al 2012). Cotton (1982) defines warm clouds as clouds in which the ice phase does not play a substantial role in the precipitation process. In the Amazon, specifically in the Belém and Manaus regions, the main targeted precipitation regimes were tropical squall lines (Cohen et al 1995); local convection, which is strongly forced by the diurnal cycle (Machado et al 2002); and mesoscale convective systems (Rickenbach 2004).…”

mentioning

confidence: 99%

The Chuva Project: How Does Convection Vary across Brazil?

Machado

Dias

Morales

et al. 2014

Bulletin of the American Meteorological Society

118

View full text Add to dashboard Cite

CHUVA, meaning “rain” in Portuguese, is the acronym for the Cloud Processes of the Main Precipitation Systems in Brazil: A Contribution to Cloud-Resolving Modeling and to the Global Precipitation Measurement (GPM). The CHUVA project has conducted five field campaigns; the sixth and last campaign will be held in Manaus in 2014. The primary scientific objective of CHUVA is to contribute to the understanding of cloud processes, which represent one of the least understood components of the weather and climate system. The five CHUVA campaigns were designed to investigate specific tropical weather regimes. The first two experiments, in Alcantara and Fortaleza in northeastern Brazil, focused on warm clouds. The third campaign, which was conducted in Belém, was dedicated to tropical squall lines that often form along the sea-breeze front. The fourth campaign was in the Vale do Paraiba of southeastern Brazil, which is a region with intense lightning activity. In addition to contributing to the understanding of cloud process evolution from storms to thunderstorms, this fourth campaign also provided a high-fidelity total lightning proxy dataset for the NOAA Geostationary Operational Environmental Satellite (GOES)-R program. The fifth campaign was carried out in Santa Maria, in southern Brazil, a region of intense hailstorms associated with frequent mesoscale convective complexes. This campaign employed a multimodel high-resolution ensemble experiment. The data collected from contrasting precipitation regimes in tropical continental regions allow the various cloud processes in diverse environments to be compared. Some examples of these previous experiments are presented to illustrate the variability of convection across the tropics.

show abstract

Modification of Precipitation from Warm Clouds—A Review

Cited by 26 publications

References 92 publications

Aerosol-cloud-precipitation effects over Germany as simulated by a convective-scale numerical weather prediction model

Aerosol-cloud-precipitation effects over Germany as simulated by a convective-scale numerical weather prediction model

Effect of hygroscopic seeding on warm rain clouds – numerical study using a hybrid cloud microphysical model

The Chuva Project: How Does Convection Vary across Brazil?

Contact Info

Product

Resources

About