Sensitivity of Numerical Simulations of a Mesoscale Convective System to Ice Hydrometeors in Bulk Microphysical Parameterization
Sensitivity of Numerical Simulations of a Mesoscale Convective System to Ice Hydrometeors in Bulk Microphysical Parameterization
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DOI：
10.1007/s00024-018-1787-z
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发表时间：
2019-05
影响因子：
2
通讯作者：
Z. Pu;Chao Lin;Xiquan Dong;S. Krueger
中科院分区：
文献类型：
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作者：
Z. Pu;Chao Lin;Xiquan Dong;S. Krueger
中尺度对流系统及其云的特性是影响航空活动的重要因素，也是数值天气预报的一个挑战。在这项研究中，在美国南部大平原的MCS冰水凝物在散装微物理（MP）计划的数值模拟的敏感性进行了研究，使用天气研究和预报（WRF）模式。结果表明，WRF单矩6类（WSM6）、WRF双矩6类（（WDM6，仅对暖雨进行双矩处理）和莫里森双矩（MORR，采用暖雨和冰的双矩表示）方案。与观测结果相比，WRF模拟的对流结构与WSM6只产生了一个不太有组织的对流结构，具有较短的寿命，而WDM6可以很好地产生MCS的结构和长度。这两种模拟都严重低估了降水量、雷达回波顶部高度和层状云分数。使用MORR，模式在预测对流的寿命、云量、回波顶和降水量方面表现良好。总体结果表明，包括冰水凝物的双矩表示沿着与暖雨的重要性。进行额外的实验，以进一步研究冰水凝物在MCS的数值模拟中的作用。结果表明，在MORR方案中用冰雹代替，可以提高对流结构的预报效果，特别是对流核心区。
Mesoscale convective systems (MCSs) and their associated cloud properties are the important factors that influence the aviation activities, yet they present a forecasting challenge in numerical weather prediction. In this study, the sensitivity of numerical simulations of an MCS over the US Southern Great Plains to ice hydrometeors in bulk microphysics (MP) schemes has been investigated using the Weather Research and Forecasting (WRF) model. It is found that the simulated structure, life cycle, cloud coverage, and precipitation of the convective system as well as its associated cold pools are sensitive to three selected MP schemes, namely, the WRF single-moment 6-class (WSM6), WRF double-moment 6-class (WDM6, with the double-moment treatment of warm-rain only), and Morrison double-moment (MORR, with the double-moment representation of both warm-rain and ice) schemes. Compared with observations, the WRF simulation with WSM6 only produces a less organized convection structure with a short lifetime, while WDM6 can produce the structure and length of the MCS very well. Both simulations heavily underestimate the precipitation amount, the height of the radar echo top, and stratiform cloud fractions. With MORR, the model performs well in predicting the lifetime, cloud coverage, echo top, and precipitation amount of the convection. Overall results demonstrate the importance of including double-moment representation of ice hydrometeors along with warm-rain. Additional experiments are performed to further examine the role of ice hydrometeors in numerical simulations of the MCS. Results indicate that replacing graupel with hail in the MORR scheme improves the prediction of the convective structure, especially in the convective core region.