陈明轩,王迎春,高峰,王婷婷. 2011. 基于雷达资料4DVar的低层热动力反演系统及其在北京奥运期间的初步应用分析[J]. 气象学报, 69(1):64-78, doi:10.11676/qxxb2011.006
基于雷达资料4DVar的低层热动力反演系统及其在北京奥运期间的初步应用分析
A low-level thermo dynamical retrieval system based on the radar data 4DVar and a preliminary analysis of its applications in support of the Beijing 2008 Olympics
投稿时间:2010-01-04  修订日期:2010-03-12
DOI:10.11676/qxxb2011.006
中文关键词:  多普勒雷达,对流风暴, 热动力反演
英文关键词:Doppler,radar, Convective storm, 4DVar, Thermo,dynamical retrieval
基金项目:公益性行业(气象)科研专项“京津冀城市群强对流天气短时临近预报关键技术研究”(GYHY200706004)
作者单位
陈明轩 中国气象局北京城市气象研究所北京100089 
王迎春 北京市气象局北京 100089 
高峰 中国气象局北京城市气象研究所北京 100089 
王婷婷 中国气象局北京城市气象研究所北京 100089中国气象科学研究院北京100081 
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中文摘要:
      在变分多普勒雷达分析系统(VDRAS)中,通过对雷达资料的质量控制和预处理、云尺度模式的暖雨参数化方案、中尺度初猜场的插值分析方法、循环同化的冷启动和热启动中尺度背景场的计算方案等进行改进,实现了VDRAS对低层动力和热力场的分析反演及其在北京奥运期间的实时应用。改进后的VDRAS利用四维变分(4DVar)同化技术和一个包含简化暖雨参数化方案的云尺度模式,对北京和天津2部S波段天气雷达资料进行12 min间隔的快速更新循环同化分析,反演与对流风暴生消发展密切相关的低层热动力三维结构,包括水平风场、垂直速度、辐合辐散、扰动温度、扰动温度梯度等,以及它们的时间增量。通过对北京奥运期间2个风暴个例的实时反演结果的分析表明,VDRAS反演的动力场能够反映低层的水平辐合、垂直抬升、风暴出流及它们的变化特征,而热力场则能够反映与风暴相伴随的冷池结构及其变化、阵风锋的相对位置及强弱。VDRAS的反演结果符合风暴发展传播与冷池、阵风锋、辐合抬升之间关系的概念模型。利用边界层风廓线雷达、地面自动站及地基微波辐射仪的观测资料,对VDRAS实时反演结果的初步统计检验表明,反演的风场和温度场与观测比较接近,风场能够反映出与风暴密切相关的低层风的垂直切变特征,温度场则能够反映出由于风暴过程所导致的地面温度的剧烈变化。与风廓线观测相比,反演的低层风速偏弱,偏差和均方根误差分别在-1.5 m/s和2.5 m/s以内,而风向的偏差和均方根误差分别在20°和45°以内。与地基微波辐射仪观测相比,反演的低层温度偏低,偏差和均方根误差分别在-1.9℃和2.8℃以内。
英文摘要:
      The Variational Doppler Radar Analysis System (VDRAS) has been further developed through improving the quality control and preprocessing of radar data, the warm rain parameterization scheme of a cloud scale model, the interpolation and analysis method of meso-scale first guess, and the calculation schemes of meso-scale background for both cold start and warm-start cycles, and applied to the real-time retrieve dynamical and thermal fields at low levels in support of the Beijing 2008 Olympics. The developed VDRAS retrieves the three-dimensional thermo dynamical fields nearly related to the convective storm initiation and evolvement, including the horizontal wind, vertical velocity, convergence and divergence, perturbation temperature and its gradient, as well as the 12 min time increment of those fields at low-level by assimilation to the Beijing and Tianjin S-band radar data via the 12-min rapid update cycling mode using 4DVar and the cloud-scale model with a simplified warm-rain parameterization scheme. The analysis of real-time retrieval results for the two storm cases during the 2008 Olympics shows that retrieved dynamical fields can indicate horizontal convergence, vertical updraft, storm outflow and their change with time at low-level. The analysis of retrieved thermal fields can indicate cold pool and its change with time, as well as the location and intensity of gust front nearly related to storm development. The VDRAS retrieval is very consistent with the conception model concerning the relationship between the storm development and the cold pool, gust front, convergence and updraft that found by many former studies. Preliminary comparison and verification on the retrieved wind and temperature fields from the VDRAS against observations from a boundary layer wind profiler, the Auto Weather Stations and a ground based radiometrics indicate the retrieval results are close to observations. Theretrieved wind can reveal the vertical shear of low-level wind that can also be observed from the profiler and is a very important factor with respect to storm development, and the retrieved temperature can reveal distinct changes in the air temperature with time that can also be observed from the AWSs while a storm passes through. The retrieved low-level wind speed is smaller than observations from the profiler and has the maximal bias of -1.5 m/s and the maximal root mean square (rms) error of 2.5 m/s. The maximal bias and rms error of the retrieved wind direction are 20 and 45 degrees against observations from the profiler, respectively. The retrieved low level temperature has the maximal bias of -1.9 Celsius degrees and the maximal rms error of 2.8 Celsius degrees, and is lower than observations from the radiometrics.
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