Parameterizations of Entrainment‐Mixing Mechanisms and Their Effects on Cloud Droplet Spectral Width Based on Numerical Simulations

Luo, Shi; Lu, Chen; Liu, Yangang; Bian, Jianchun; Li, Junjun; Xu, Xiaoqi; Gao, Sinan; Yang, Shuangyan; Guo, Xiaohao

doi:10.1029/2020jd032972

Cited by 25 publications

(45 citation statements)

References 111 publications

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“…The evolution of r v is more complicated than that of n c and LWC; r v increases for the broad initial CDSDs ( μ = 0.5, 2.0) but decreases for the narrow ones ( μ = 10.0, 40.0). The reason is that the CDSDs with μ = 0.5, 2.0 are mainly composed of small droplets and complete evaporation of small droplets dominates the evaporation (Luo et al., 2020). The remaining big droplets have a larger r v than the initial CDSDs.…”

Section: Resultsmentioning

confidence: 99%

“…In total, 143 out of 216 cases (66.2%) meet the cloud criteria after entrainment‐mixing. These factors (RH e , ɛ , and f ) are reported to have significant effects on microphysical properties and homogeneous mixing degree (Krueger et al., 1997; Kumar et al., 2014; Lu, Liu, Niu, Krueger, & Wagner, 2013; Luo et al., 2020; Pinsky & Khain, 2018; Pinsky et al., 2016; Su et al., 1998; Tölle & Krueger, 2014). For instance, Lu, Liu, Niu, Krueger, and Wagner (2013) and Luo et al.…”

Section: Resultsmentioning

confidence: 99%

“…For instance, Lu, Liu, Niu, Krueger, and Wagner (2013) and Luo et al. (2020) showed that the homogeneous mixing degree decreased as f increased, suggesting a larger f caused a smaller homogeneous mixing degree since the complete evaporation of droplets was more likely to occur when the amount of evaporation increased. The microphysical relationships are often used to parameterize d in models (Peng & Lohmann, 2003; Rotstayn & Liu, 2003, 2009; Xie & Liu, 2011; Xie et al., 2017).…”

Section: Resultsmentioning

confidence: 99%

“…From the microphysical perspective, our previous studies have measured the entrainment‐mixing process through four homogeneous mixing degrees ( ψ j , where j is from 1 to 4) (S. Gao et al., 2020; Z. Gao et al., 2018; Lu, Liu, & Niu, 2014; Lu, Liu, Niu, & Endo, 2014; Lu, Liu, Niu, Krueger, & Wagner, 2013; Luo et al., 2020):

ψ_{1} = \frac{2}{π} \tan^{- 1} (\frac{\frac{{r_{v}}^{3}}{{r_{va}}^{3}} - 1}{\frac{n_{normalc}}{n_{normala}} - \frac{n_{normalh}}{n_{normala}}}),

n_{normalh} = χ n_{normala} .

ψ_{2} = \frac{1}{2} (\frac{n_{c} - n_{i}}{n_{h} - n_{i}} + \frac{{r_{normalv}}^{3} - {r_{va}}^{3}}{{r_{vh}}^{3} - {r_{va}}^{3}}),

r_{vh}^{3} = \frac{n_{c}}{n_{h}} r_{normalv}^{3},

n_{normali} = \frac{r_{v}^{3}}{r_{va}^{3}} n_{normalc} .

ψ_{3} = \frac{\ln n_{normalc} - \ln n_{normali}}{\ln n_{normalh} - \ln}

…”

Section: Methods and Modelmentioning

confidence: 99%

“…These methods are further applied to identify the entrainment-mixing types and establish parameterizations of entrainment-mixing mechanism (S. Gao et al, 2020;Z. Gao et al, 2018;Lu, Liu, Zhu, et al, 2018;Luo et al, 2020).…”

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confidence: 99%

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Consideration of Initial Cloud Droplet Size Distribution Shapes in Quantifying Different Entrainment‐Mixing Mechanisms

Luo

Liu

et al. 2021

JGR Atmospheres

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Entrainment‐mixing process significantly affects cloud micro/macrophysics and the evaluation of aerosol indirect effects. However, it is still an open question as to how to quantify entrainment‐mixing mechanism for broad cloud droplet size distributions (CDSDs). Here, CDSDs with different spectral widths are used to initialize the Explicit Mixing Parcel Model to address this problem, and microphysical properties are compared for different CDSD widths. For relatively broad CDSDs, as the number concentration and liquid water content decrease, the volume‐mean radius and mean radius increase, which is opposite to the scenario for relatively narrow CDSDs and the homogeneous/inhomogeneous conceptual model. For the relatively broad CDSDs, such relationships could be mistaken as inhomogeneous mixing with subsequent ascent in analysis of the conventional microphysical mixing diagram. This then causes traditional homogenous mixing degrees to be unrealistically negative and not applicable for relatively broad CDSDs. New measures are introduced to explicitly account for the effect of CDSD spectral shapes on quantifying entrainment‐mixing mechanism. The new measures yield reasonable ranges of values that conform to the dynamical measures such as the Damköhler and transitional scale numbers, and their temporal variation can be explained physically. This study extends the measures of homogeneous mixing degrees from narrow to broad CDSDs, and sheds new light on the consideration of CDSD shapes in parameterizations of entrainment‐mixing mechanism.

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Section: Resultsmentioning

confidence: 99%