Effect of Single and Double Moment Microphysics Schemes and Change in Cloud Condensation Nuclei, Latent Heating Rate Structure Associated with Severe Convective System over Korean Peninsula

Abstract

To investigate the impact of advanced microphysics schemes using single and double moment (WSM6/WDM6) schemes, numerical simulations are conducted using Weather Research and Forecasting (WRF) model for a severe mesoscale convective system (MCS) formed over the Korean Peninsula. Spatial rainfall distribution and pattern correlation linked with the convective system are improved in the WDM6 simulation. During the developing stage of the system, the distribution of total hydrometeors is larger in WDM6 compared to WSM6. Along with the mixing ratio of hydrometeors (cloud, rain, graupel, snow, and ice), the number concentration of cloud and rainwater are also predictable in WDM6. To understand the differences in the vertical representation of cloud hydrometeors between the schemes, rain number concentration (Nr) from WSM6 is also computed using particle density to compare with the Nr readily available in WDM6. Varied vertical distribution and large differences in rain number concentration and rain particle mass is evident between the schemes. Inclusion of the number concentration of rain and cloud, CCN, along with the mixing ratio of different hydrometers has improved the storm morphology in WDM6. Furthermore, the latent heating (LH) profiles of six major phase transformation processes (condensation, evaporation, freezing, melting, deposition, and sublimation) are also computed from microphysical production terms to deeply study the storm vertical structure. The main differences in condensation and evaporation terms are evident between the simulations due to the varied treatment of warm rain processes and the inclusion of CCN activation in WDM6. To investigate cloud–aerosol interactions, numerical simulation is conducted by increasing the CCN (aerosol) concentration in WDM6, which simulated comparatively improved pattern correlation for rainfall simulation along with intense hydrometer distribution. It can be inferred that the change in aerosol increased the LH of evaporation and freezing and affected the warming and cooling processes, cloud vertical distribution, and subsequent rainfall. Relatively, the WDM6 simulated latent heating profile distribution is more consistent with the ERA5 computed moisture source and sink terms due to the improved formulation of warm rain processes.

Climatology of thermodynamic indices and background synoptic conditions responsible for severe convection during pre‐ to post‐monsoon seasons over Indian region

“…Main favourable conditions include the suitable synoptic conditions to cause the low‐level convergence and upper‐level divergence which act as trigger to release the instability present in air mass; dynamical mechanism to release the instability due to upper airflow which advects the warmer air in the lower troposphere and cold air in the upper atmosphere to increase the instability; day‐time heating and orography, conditional and convective instability in the atmosphere; adequate supply of moisture in the lower troposphere. In general, SCS are linked with convective (deep vertical structure, strong updrafts, downdrafts, and heavy rains) and stratiform clouds (shallow with greater horizontal homogeneity, weak vertical motion, and light rains) (Houze & Rappaport, 1984; Rajeevan et al, 2010; Madhulatha et al, 2020; 2023). Convective clouds are characterized by the low‐level convergence transitioning to divergence at upper levels which transfers sensible and latent heat throughout the troposphere (Da Silva & Haerter, 2023).…”

Diagnostic Analysis of Diabatic Heating in an Extreme Rainfall Event in Shandong Province, China

“…Precipitation processes dominated by warm clouds are more efficient. In cold clouds, diabatic heating can promote the formation and growth of ice crystals, thereby altering the nature of the clouds and the precipitation process [26,27].…”