Relationships between Cloud Droplet Spectral Relative Dispersion and Entrainment Rate and Their Impacting Factors

Between Broadening and Narrowing: How Mixing Affects the Width of the Droplet Size Distribution

“…However, IHMD and ɛ are not uniquely related to each other (Figure 4c compared to Figure 3b), which is in good agreement with Luo et al. (2022). This might be due to the fact that ɛ can vary substantially during the mixing processes, making a single value, as used in Figure 4c, inadequate for representing the entire process.…”

“…In the homogeneous mixing scenario, the net activation rate can be positive due to the negligible amount of droplets deactivated, and activated droplets can contribute to DSD broadening toward smaller sizes. This is in good agreement with Krueger et al (2008) and Luo et al (2022), who found that DSDs can be broadened after mixing when ascending motions enable activation of entrained aerosol particles. However, the number of activated droplets is negligible in our simulation, even if the net activation rate is positive.…”

“…(2008) and Luo et al. (2022), who found that DSDs can be broadened after mixing when ascending motions enable activation of entrained aerosol particles. However, the number of activated droplets is negligible in our simulation, even if the net activation rate is positive.…”

“…In recent years, it has been suggested that other effects, for example, the faster evaporation of small droplets and dynamical motions of the cloud (Luo et al., 2020, 2021, 2022; Pinsky et al., 2016; Tölle & Krueger, 2014), or the so‐called secondary activation of entrained aerosol particles above cloud base (Chandrakar et al., 2021; Krueger et al., 2008; Lu et al., 2020; Luo et al., 2022) can also affect how mixing changes the DSD in ways that are not covered by the aforementioned idealized framework of homogeneous and inhomogeneous mixing. In particular, it was suggested that DSDs could be either broadened or narrowed during mixing inside an updraft when secondary activation is possible or not (Krueger et al., 2008; Lu et al., 2020).…”

“…Thus, the effects of different mixing scenarios need to be investigated in more sophisticated modeling frameworks considering SGS processes. So far, this has been done in idealized frameworks with many prescribed or simplified parameters (e.g., relative humidity of entrained airmasses, turbulent kinetic dissipation rate) (Desai et al., 2021; Kumar et al., 2013; Lu et al., 2013; Luo et al., 2022; Tölle & Krueger, 2014). However, questions still remain whether these findings are applicable to more realistic settings where the large‐scale cloud dynamics determine these parameters naturally.…”