The effects of giant cloud condensation nuclei on the development of precipitation in convective clouds — a numerical study

Yin, Yan; Levin, Zev; Reisin, Tamir; Tzivion, Shalva

doi:10.1016/s0169-8095(99)00046-0

Cited by 211 publications

(213 citation statements)

References 43 publications

Supporting

Mentioning

197

Contrasting

Unclassified

Order By: Relevance

“…As important as the radiative effect is the impact of the dust on precipitation. It has been commonly believed that the larger concentrations of large and giant CCN, regardless of the distribution of the smaller CCN, can lead to enhanced coalescence and precipitation in convective clouds (4). However, here we show that the coalescencesuppressing effects of the large concentrations of small dust particles and the insoluble larger particles dominate over the enhancing effects of the giant CCN.…”

Section: Climatic Perspective Of Dust-cloud Interactionscontrasting

confidence: 70%

“…They also suspected that the difference in r e might lead to a reduction in the precipitation efficiency of the African clouds by up to a factor of 2, compared with the clouds over the Amazon. It is important to note that the detrimental impact on precipitation shown here occurs on the background of relatively clean maritime and continental-tropical air, whereas the previous indications for desert dust enhancing coalescence (3,4) occur on the background of desert dust interacting with already polluted air by sulfur emissions, which were already shown to strongly suppress precipitation (2).…”

Section: Climatic Perspective Of Dust-cloud Interactionsmentioning

confidence: 51%

“…Desert dust that passes over polluted areas often can be coated by sulfur due to chemical processes on their surface (3). These particles then can serve as giant CCN, which may enhance the collision and coalescence of droplets and therefore increase warm precipitation formation and decrease the clouds' albedo (4). However, our satellite, aircraft, and laboratory observations show that mineral dust suppresses precipitation.…”

Section: Satellite Observations Of Cloud-dust Interactionsmentioning

confidence: 75%

See 2 more Smart Citations

Desert dust suppressing precipitation: A possible desertification feedback loop

Rosenfeld

Rudich

Lahav

2001

Proc. Natl. Acad. Sci. U.S.A.

698

512

View full text Add to dashboard Cite

The effect of desert dust on cloud properties and precipitation has so far been studied solely by using theoretical models, which predict that rainfall would be enhanced. Here we present observations showing the contrary; the effect of dust on cloud properties is to inhibit precipitation. Using satellite and aircraft observations we show that clouds forming within desert dust contain small droplets and produce little precipitation by drop coalescence. Measurement of the size distribution and the chemical analysis of individual Saharan dust particles collected in such a dust storm suggest a possible mechanism for the diminished rainfall. The detrimental impact of dust on rainfall is smaller than that caused by smoke from biomass burning or anthropogenic air pollution, but the large abundance of desert dust in the atmosphere renders it important. The reduction of precipitation from clouds affected by desert dust can cause drier soil, which in turn raises more dust, thus providing a possible feedback loop to further decrease precipitation. Furthermore, anthropogenic changes of land use exposing the topsoil can initiate such a desertification feedback process. Satellite Observations of Cloud-Dust InteractionsT he three major sources of aerosols in the atmosphere are desert dust, smoke from biomass burning, and anthropogenic air pollution. The latter two are recognized as sources of large concentrations of small cloud condensation nuclei (CCN), which lead to the formation of a high concentration of small cloud droplets and therefore to an increased cloud albedo (1) and suppressed precipitation (2). Desert dust that passes over polluted areas often can be coated by sulfur due to chemical processes on their surface (3). These particles then can serve as giant CCN, which may enhance the collision and coalescence of droplets and therefore increase warm precipitation formation and decrease the clouds' albedo (4). However, our satellite, aircraft, and laboratory observations show that mineral dust suppresses precipitation. Possible causes for this apparent contradiction are discussed later.Data from the Advanced Very High-Resolution Radiometer (AVHRR) onboard the National Oceanographic and Atmospheric Administration satellite were used for retrieving properties of clouds that formed during a heavy dust storm in March 1998 over the Eastern Mediterranean. The satellite image is shown in Fig. 1, using the microphysical color scheme of Rosenfeld and Lensky (5). The dust rapidly advected from the Sahara through Southern Israel, Jordan, and Syria and curled back through Turkey into the center of a cyclonic depression over Cyprus. A ''tongue'' of dust-free air converged into the cyclone from the north and west. Shallow convective clouds of similar depth and shapes developed over the sea and the adjacent land in both dust laden and dust-free regions. Retrieval of cloud microstructure (see Fig. 2) reveals that the droplets in clouds that formed in the dust-free zone had large effective radii (r e ) that steeply increased with heigh...

show abstract

Section: Climatic Perspective Of Dust-cloud Interactionscontrasting

confidence: 70%

Section: Climatic Perspective Of Dust-cloud Interactionsmentioning

confidence: 51%

Section: Satellite Observations Of Cloud-dust Interactionsmentioning

confidence: 75%

See 1 more Smart Citation

Desert dust suppressing precipitation: A possible desertification feedback loop

Rosenfeld

Rudich

Lahav

2001

Proc. Natl. Acad. Sci. U.S.A.

698

512

View full text Add to dashboard Cite

show abstract

“…The improved calculation of some of the microphysical processes such as drop nucleation, and immersion freezing of drops, presented by Yin et al (2000), were also introduced. In the model, a set of dynamic equations were solved for the vertical and radial velocity, the pressure perturbation, the virtual potential temperature perturbation, the specific humidity perturbation, the specific concentration of aerosols, the specific number and mass for each type of cloud particles in a spectral bin, and concentration of activated ice nuclei.…”

Section: The Model Dynamics and Microphysicsmentioning

confidence: 99%

Redistribution of trace gases by convective clouds - mixed-phase processes

2002

View full text Add to dashboard Cite

Abstract. The efficiency of gas transport to the free and upper troposphere in convective clouds is investigated in an axisymmetric dynamic cloud model with detailed microphysics. In particular, we examine the sensitivity of gas transport to the treatment of gas uptake by different ice hydrometeors. Two parameters are used to describe this uptake. The gas retention coefficient defines the fraction of dissolved gas that is retained in an ice particle upon freezing, which includes also the riming process. We also define a gas burial efficiency defining the amount of gas entrapped in ice crystals growing by vapour diffusion. Model calculations are performed for continental and maritime clouds using a complete range of gas solubilities, retention coefficients and burial efficiencies. The results show that the magnitude of the gas retention coefficient is much more important for gas transport in maritime clouds than in continental clouds. The cause of this difference lies in the different microphysical processes dominating the formation and evolution of hydrometeors in the two cloud types. For highly soluble gases, the amount of gas transported to the free troposphere in maritime clouds falls approximately linearly by a factor of 12 as the retention coefficient is varied between 0 and 1. Gas transport is relatively insensitive to the magnitude of the gas burial efficiency. However, the burial efficiency strongly controls the concentration of trace gases inside anvil ice crystals, which subsequently form cirrus clouds.

show abstract

“…First, turbulenceinduced mixing and entrainment can trigger in-cloud activation of haze particles, which can broaden the left branch of the size distribution (e.g., Khain et al, 2000;Devenish et al, 2012;Yang et al, 2016;Grabowski et al, 2018). Secondly, giant cloud condensational nuclei (GCCN, usually defined as aerosols with a dry diameter larger than a few µm) provides an embryo for large droplets, which can broaden the right branch of the size distribution and can be important for warm rain initiation (e.g., Johnson, 1982;Feingold et al, 1999;Yin et al, 2000;Jensen and Lee, 2008;Cheng et al, 2009). Recently, Jensen and Nugent (2017) investigated the effect of GCCN on droplet growth and rain formation using a cloud parcel model.…”

mentioning

confidence: 99%

Cloud droplet size distribution broadening during diffusional growth: ripening amplified by deactivation and reactivation

et al. 2018

View full text Add to dashboard Cite

Abstract. Cloud droplet size distributions (CDSDs), which are related to cloud albedo and rain formation, are usually broader in warm clouds than predicted from adiabatic parcel calculations. We investigate a mechanism for the CDSD broadening using a moving-size-grid cloud parcel model that considers the condensational growth of cloud droplets formed on polydisperse, submicrometer aerosols in an adiabatic cloud parcel that undergoes vertical oscillations, such as those due to cloud circulations or turbulence. Results show that the CDSD can be broadened during condensational growth as a result of Ostwald ripening amplified by droplet deactivation and reactivation, which is consistent with early work. The relative roles of the solute effect, curvature effect, deactivation and reactivation on CDSD broadening are investigated. Deactivation of smaller cloud droplets, which is due to the combination of curvature and solute effects in the downdraft region, enhances the growth of larger cloud droplets and thus contributes particles to the larger size end of the CDSD. Droplet reactivation, which occurs in the updraft region, contributes particles to the smaller size end of the CDSD. In addition, we find that growth of the largest cloud droplets strongly depends on the residence time of cloud droplet in the cloud rather than the magnitude of local variability in the supersaturation fluctuation. This is because the environmental saturation ratio is strongly buffered by numerous smaller cloud droplets. Two necessary conditions for this CDSD broadening, which generally occur in the atmosphere, are as follows: (1) droplets form on aerosols of different sizes, and (2) the cloud parcel experiences upwards and downwards motions. Therefore we expect that this mechanism for CDSD broadening is possible in real clouds. Our results also suggest it is important to consider both curvature and solute effects before and after cloud droplet activation in a cloud model. The importance of this mechanism compared with other mechanisms on cloud properties should be investigated through in situ measurements and 3-D dynamic models.

show abstract

The effects of giant cloud condensation nuclei on the development of precipitation in convective clouds — a numerical study

Cited by 211 publications

References 43 publications

Desert dust suppressing precipitation: A possible desertification feedback loop

Desert dust suppressing precipitation: A possible desertification feedback loop

Redistribution of trace gases by convective clouds - mixed-phase processes

Cloud droplet size distribution broadening during diffusional growth: ripening amplified by deactivation and reactivation

Contact Info

Product

Resources

About