Abstract Two momentum control variable schemes are typically used in most data assimilation systems: stream function and unbalanced velocity potential (ψ/χu scheme) and eastward and northward velocity (U/V scheme). The wind profiler radar (profiler) plays an important role in the expansion of meteorological observations networks. In this study, the impacts of two momentum control variable schemes on assimilating a dense wind profiler network are discussed based on the single profiler station observation tests and six convective rainfall events cycling experiments. Single profiler station observation tests indicate that profiler data assimilation is sensitive to control variables. The dynamical increments using U/V scheme contain more elaborate structure, which contributes to valuing the straightforward effects of profiler observations objectively. By contrast, unrealistic increments occur around the observation station in the experiment using ψ/χu scheme. Six continuous cycling experiments further demonstrate that, for convective rainfall events, experiment using U/V scheme leads to more skillful quantitative precipitation forecasts of convective rainfall. Diagnostic analysis results show that analysis using ψ/χu scheme prevents a good fitting to the profiler data, and accurate dynamical analysis containing abundant small-scale disturbances are the main reason for improving precipitation prediction of convective rainfall when U/V scheme is adopted.

中文翻译：

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密集风廓线仪网络的数据同化及其对对流预报的影响

摘要 大多数数据同化系统通常使用两种动量控制变量方案：流函数和不平衡速度势（ψ/χu方案）和东向和北向速度（U/V方案）。风廓线雷达（profiler）在气象观测网络的扩展中发挥着重要作用。在本研究中，基于单个剖面站观测测试和六个对流降雨事件循环实验，讨论了两种动量控制变量方案对同化密集风廓线网络的影响。单剖面站观测试验表明剖面资料同化对控制变量很敏感。使用 U/V 方案的动态增量包含更精细的结构，这有助于客观评估剖面仪观测的直接效果。相比之下，在使用 ψ/χu 方案的实验中，观测站周围出现了不切实际的增量。六个连续循环实验进一步证明，对于对流降雨事件，使用U/V方案的实验可以更熟练地对对流降雨进行定量降水预报。诊断分析结果表明，采用ψ/χu方案进行分析无法很好地拟合廓线数据，而在采用U/V方案时，包含大量小尺度扰动的准确动力分析是提高对流降雨降水预报的主要原因。使用 U/V 方案的实验可以更熟练地对对流降雨进行定量降水预报。诊断分析结果表明，采用ψ/χu方案进行分析无法很好地拟合廓线数据，而在采用U/V方案时，包含大量小尺度扰动的准确动力分析是提高对流降雨降水预报的主要原因。使用 U/V 方案的实验可以更熟练地对对流降雨进行定量降水预报。诊断分析结果表明，采用ψ/χu方案进行分析无法很好地拟合廓线数据，而在采用U/V方案时，包含大量小尺度扰动的准确动力分析是提高对流降雨降水预报的主要原因。