An Analysis of Cloud Drop Growth by Collection: Part I. Double Distributions

Berry, Edwin X.; Reinhardt, R. Lee

doi:10.1175/1520-0469(1974)031<1814:aaocdg>2.0.co;2

Cited by 213 publications

(121 citation statements)

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“…The size distribution in C5 (dashed line) is similar to the ones in C1 to C4 (grey lines). Numerical simulations of the onset of precipitation generally show that the collection process initially produces drizzle drops, which progressively grow to precipitation drops (Berry and Reinhardt, 1974). Our observations do not replicate the results of the simulations, suggesting that the early stage of drizzle drop formation probably occurred either lower or higher than the sampling level or that it was too fast for the series of cloud traverses to catch the transition.…”

Section: Drizzle and Precipitation Drop Distributionscontrasting

confidence: 85%

The onset of precipitation in warm cumulus clouds: An observational case‐study

Burnet

Brenguier

2010

Quart J Royal Meteoro Soc

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Although the three clouds showed similar values of the droplet number concentrations and were able to generate precipitation embryos, the first two collapsed after reaching an altitude of 3 km above sea level, without producing any precipitation, while the third one reached a higher level of 4 km and produced significant precipitation. This case-study illustrates how sensitive the onset of precipitation is to cloud dynamics, revealing that in a conditionally unstable atmosphere hardly noticeable changes in cloud thermodynamics and microphysics may lead to major changes in cloud vertical development and precipitation.

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Section: Drizzle and Precipitation Drop Distributionscontrasting

confidence: 85%

The onset of precipitation in warm cumulus clouds: An observational case‐study

Burnet

Brenguier

2010

Quart J Royal Meteoro Soc

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“…We compare the results using the turbulent kernel to those using the Hall kernel. The plots naturally reveal the three growth phases first described qualitatively in Berry and Reinhardt (1974): (1) the autoconversion phase in which self-collections of small cloud droplets near the peak of the initial size distribution slowly shift the initial peak of the distribution toward larger sizes; (2) the accretion phase in which the accretion mode dominates over the autoconversion mode and serves to quickly transfer mass from the initial peak to the newly formed secondary peak at drizzle sizes; and (3) the large hydrometeor self-collection phase in which the self-collections of drizzle droplets move the second peak toward the raindrop sizes (a few millimeters). By examining the locations corresponding to the maximum and minimum ∂g/∂t, one can unambiguously identify the time intervals of the three phases (Xue et al, 2008).…”

Section: Several Important Observations Can Be Made Frommentioning

confidence: 93%

“…A small bin mass ratio of 2 0.25 ensures that the numerical solutions are free from numerical diffusion and dispersion errors. The mass distribution g(ln r, t) ≡ 3x 2 n(x , t) is usually plotted at different times in order to examine growth processes (Berry and Reinhardt, 1974). In Figure 4, we instead plot the local rate of change, ∂g/∂t, as a function of radius for times from 0 to 60 min every 1 min.…”

Section: Several Important Observations Can Be Made Frommentioning

confidence: 99%

The role of air turbulence in warm rain initiation

Wang

Grabowski

2009

Atmospheric Science Letters

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Quantitative parameterization of turbulent collision of cloud droplets represents a major unsolved problem in cloud physics. Here a hybrid direct simulation tool is used specifically to quantify the turbulent enhancement of the gravitational collision-coalescence. Simulation results show that air turbulence can enhance the collision kernel by an average factor of about 2, and the observed trends are supported by scaling arguments. An impact study using the most realistic collection kernel suggests that cloud turbulence can significantly reduce the time for warm rain initiation. Areas for further development of the hybrid simulation and the impact study are indicated.

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“…Although various numerical methods are available to solve Eq. (7) directly (e.g., Berry and Reinhardt, 1974;Bott, 1998;Tzivion et al, 1999;Shima et al, 2009), this is most often seen as computationally too expensive in three-dimensional atmospheric models. Therefore bulk parameterizations are used which predict only a limited number of (partial) moments of the drop size distribution.…”

Section: Parameterization Of Turbulence Effects On Autoconversionmentioning

confidence: 99%

Turbulence effects on warm-rain formation in precipitating shallow convection revisited

Seifert

Onishi

2016

Atmos. Chem. Phys.

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Abstract. Two different collection kernels which include turbulence effects on the collision rate of liquid droplets are used as a basis to develop a parameterization of the warmrain processes autoconversion, accretion, and self-collection. The new parameterization is tested and validated with the help of a 1-D bin microphysics model. Large-eddy simulations of the rain formation in shallow cumulus clouds confirm previous results that turbulence effects can significantly enhance the development of rainwater in clouds and the occurrence and amount of surface precipitation. The detailed behavior differs significantly for the two turbulence models, revealing a considerable uncertainty in our understanding of such effects. In addition, the large-eddy simulations show a pronounced sensitivity to grid resolution, which suggests that besides the effect of sub-grid small-scale isotropic turbulence which is parameterized as part of the collection kernel also the larger turbulent eddies play an important role for the formation of rain in shallow clouds.

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An Analysis of Cloud Drop Growth by Collection: Part I. Double Distributions

Cited by 213 publications

References 0 publications

The onset of precipitation in warm cumulus clouds: An observational case‐study

The onset of precipitation in warm cumulus clouds: An observational case‐study

The role of air turbulence in warm rain initiation

Turbulence effects on warm-rain formation in precipitating shallow convection revisited

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