Effects of turbulence‐induced collision enhancement on heavy precipitation: The 21 September 2010 case over the Korean Peninsula

Abstract

The effects of turbulence‐induced collision enhancement (TICE) on a heavy precipitation event that occurred on 21 September 2010 over the middle Korean Peninsula are examined. For this purpose, an updated bin microphysics scheme incorporating TICE for drop‐drop and drop‐graupel collisions is implemented into the Weather Research and Forecasting (WRF) model. The numerical simulation shows some differences in the strong precipitation system compared to the observations but generally captures well the important features of observed synoptic conditions, surface precipitation, and radar reflectivity. While the change in domain‐averaged surface precipitation amount due to TICE is small and similar to that due to small initial perturbations, the spatial distribution of surface precipitation amount is somewhat altered due to TICE. The surface precipitation amount is increased due to TICE in the area where the largest surface precipitation occurred, but the effects of different flow realizations also contribute to the changes. TICE accelerates the coalescence between small cloud droplets, which induces a decrease in condensation and an increase in excess water vapor transported upward. This causes an increase in relative humidity with respect to ice at high altitudes, hence increasing the depositional growth of ice particles. Therefore, the ice mass increases due to TICE, and this increase induces the increases in riming and melting of ice particles. A series of these microphysical changes due to TICE are regarded as partially contributing to the increase in surface precipitation amount in some areas, hence inducing alterations in the spatial distribution of surface precipitation amount.

Evaluation of an Improved Quasi‐stochastic Collection Model Through Precipitation Prediction Over North Central Mongolia

“…Two additional simulations are conducted to examine the impacts of different initial conditions on precipitation prediction for the case considered in this study. For this, following Lee and Baik (), the initial potential temperature at every grid point is perturbed by the random noise uniformly distributed between −0.3 K and 0.3 K in the IQS and NQS model simulations. Except for the initial potential temperature perturbations, the experimental setup is the same as that described in section 2.…”

“…To numerically simulate the precipitation event described above, the Weather Research and Forecasting (WRF) model v3.7.1 (Skamarock et al, ) is used. The bin microphysics scheme of the Hebrew University Cloud Model is implemented in the WRF model (Lee & Baik, , ). The bin microphysics scheme used in this study considers seven hydrometeor types (liquid drop, three ice crystals (column, plate, and dendrite), snow, graupel, and hail) and aerosol.…”

“…In the present study, the turbulence‐induced collision enhancement is not considered. A more description of the bin microphysics scheme is given in Khain et al () and Lee and Baik ().…”

How Mountain Geometry Affects Aerosol-Cloud-Precipitation Interactions: Part I. Shallow Convective Clouds

“…The numerical model used in this study is the Weather Research and Forecasting (WRF) model, version 3.6.1, coupled with the bin microphysics scheme of the Hebrew University Cloud Model (HUCM) (Skamarock et al 2008;Lee and Baik 2016). The detailed description of HUCM is given in Khain and Sednev (1996) and Khain et al (2000Khain et al ( , 2004.…”

Non-Monotonic Dependencies of Cloud Microphysics and Precipitation on Aerosol Loading in Deep Convective Clouds: A Case Study Using the WRF Model with Bin Microphysics

“…Large ice particles melt gradually below the melting layer according to the predicted liquid water fractions, following Phillips et al [40]. A detailed description of the bin microphysics scheme can be found in Lee and Baik [36]. Turbulence-induced collision enhancement is not considered in this study.…”