Fingerprints of a riming event on cloud radar Doppler spectra: observations and modeling
Fingerprints of a riming event on cloud radar Doppler spectra: observations and modeling
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DOI：
10.5194/acp-16-2997-2016
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发表时间：
2015-10
影响因子：
6.3
通讯作者：
H. Kalesse;W. Szyrmer;S. Kneifel;P. Kollias;E. Luke
中科院分区：
文献类型：
--
作者：
H. Kalesse;W. Szyrmer;S. Kneifel;P. Kollias;E. Luke
抽象。雷达多普勒光谱测量被用来研究一个雾凇事件时，沉淀冰从播种云沉积物通过过冷液态水（SLW）层。重点是“黄金样本”的案例研究，这种类型的分析的基础上收集的观测期间部署的大气辐射测量计划（ARM）的移动的设施AMF 2在Hyytiala，芬兰，在生物气溶胶-对云和气候的影响（BAECC）的现场活动。雷达多普勒谱的高度演变的分析是一个国家的最先进的检索与轮廓云雷达在SLW层超出传统的使用谱矩。动力学的影响被认为是通过以下粒子种群的演变沿着倾斜的轨道，在风切变条件下的云的水平平流所造成的。在SLW层中，所识别的液体峰被用作空气运动示踪剂以校正垂直空气运动的多普勒谱，并且冰峰被用于研究有边颗粒的雷达廓线。一个一维稳态箱微物理模型的约束使用SLW和空气运动廓线和云顶雷达观测。观测到的雷达矩廓线的雾凇雪可以合理地很好地模拟模型，但不是没有作出几个假设的冰粒浓度和沉积和聚集的相对作用。这表明，在面向过程的研究能够有效地评估冰的微物理参数化之前，需要对关键冰的特性进行现场观测，以补充剖面雷达观测。
Abstract. Radar Doppler spectra measurements are exploited to study a riming event when precipitating ice from a seeder cloud sediment through a supercooled liquid water (SLW) layer. The focus is on the "golden sample" case study for this type of analysis based on observations collected during the deployment of the Atmospheric Radiation Measurement Program's (ARM) mobile facility AMF2 at Hyytiala, Finland, during the Biogenic Aerosols – Effects on Clouds and Climate (BAECC) field campaign. The presented analysis of the height evolution of the radar Doppler spectra is a state-of-the-art retrieval with profiling cloud radars in SLW layers beyond the traditional use of spectral moments. Dynamical effects are considered by following the particle population evolution along slanted tracks that are caused by horizontal advection of the cloud under wind shear conditions. In the SLW layer, the identified liquid peak is used as an air motion tracer to correct the Doppler spectra for vertical air motion and the ice peak is used to study the radar profiles of rimed particles. A 1-D steady-state bin microphysical model is constrained using the SLW and air motion profiles and cloud top radar observations. The observed radar moment profiles of the rimed snow can be simulated reasonably well by the model, but not without making several assumptions about the ice particle concentration and the relative role of deposition and aggregation. This suggests that in situ observations of key ice properties are needed to complement the profiling radar observations before process-oriented studies can effectively evaluate ice microphysical parameterizations.