Ice-phase cloud microphysical processes are very complicated, and there are still many uncertainties in current microphysics parameterization schemes. In this study, two alternative ice crystal deposition/sublimation (ICDS) parameterizations, following the Harrington et al., Journal of the Atmospheric Sciences, 1995, 52, 4344–4366 and Koenig, Monthly Weather Review, 1972, 100, 417–423 methods, were implemented into the Weather Research and Forecast (WRF) Single-Moment 6-class Microphysics (WSM6) scheme in the Global/Regional Assimilation and Prediction System (GRAPES) regional operational model to investigate their impact on overestimation of snowfall over North China. The results show that the snowfall amount and cloud particle composition are very sensitive to the ICDS parameterization. Sensitivity tests with WSM6 using the Harrington and Koenig ICDSs, referred to as WSM6_H and WSM6_K, respectively, notably reduced overestimation of the snowfall amount and simulated more realistic supercooled cloud water content compared with ERA5 reanalysis data. The vertical distributions, intensities, and duration of radar echoes simulated by WSM6_H are the most consistent with millimeter-wavelength cloud radar observations. There is competition for water vapor in WSM6 due to the sequential order in which processes are updated. This tends to weaken the deposition of snow and graupel and the condensation of cloud water when the deposition of ice crystals is too strong in a cold region. In both WSM6_H and WSM6_K, the deposition processes of ice crystals are reduced and the other microphysical transformation processes become more active compared with WSM6. Overall, the WSM6_H configuration improves the forecast performance as evaluated by Taylor diagrams for eight snowfall days over North China. The ICDS parameterizations must therefore be handled carefully due to their large uncertainties in the development of the cloud microphysics schemes.

中文翻译：

---

华北降雪预报对 WSM6 云微物理方案中冰晶沉积/升华参数化的敏感性

冰相云微物理过程非常复杂，目前的微物理参数化方案还存在很多不确定性。在这项研究中，遵循 Harrington等人的两个替代冰晶沉积/升华 (ICDS) 参数化。, Journal of the Atmospheric Sc​​iences, 1995, 52, 4344–4366 和 Koenig, Monthly Weather Review, 1972, 100, 417–423 方法被应用到天气研究和预报 (WRF) 单时刻 6 级微物理学 (WSM6 ) 方案在全球/区域同化和预测系统 (GRAPES) 区域业务模型中研究其对华北降雪高估的影响。结果表明，降雪量和云粒子组成对ICDS参数化非常敏感。与 ERA5 再分析数据相比，使用 Harrington 和 Koenig ICDS（分别称为 WSM6_H 和 WSM6_K）对 WSM6 进行的敏感性测试显着减少了对降雪量的高估，并模拟了更真实的过冷云水含量。垂直分布、强度、WSM6_H模拟的雷达回波持续时间和持续时间与毫米波云雷达观测最一致。由于过程更新的顺序，WSM6 中存在对水蒸气的竞争。在寒冷地区，当冰晶沉积过强时，这往往会减弱雪和霰的沉积以及云水的凝结。在 WSM6_H 和 WSM6_K 中，与 WSM6 相比，冰晶的沉积过程减少，其他微物理转化过程变得更加活跃。总体而言，WSM6_H 配置提高了由泰勒图评估的华北地区 8 个降雪日的预测性能。由于 ICDS 参数化在云微物理方案的开发中存在很大的不确定性，因此必须谨慎处理。