Assimilation impact of high‐temporal‐resolution volume scans on quantitative precipitation forecasts in a severe storm: Evidence from nudging data assimilation experiments with a thermodynamic retrieval method
Assimilation impact of high‐temporal‐resolution volume scans on quantitative precipitation forecasts in a severe storm: Evidence from nudging data assimilation experiments with a thermodynamic retrieval method
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高时间分辨率体积扫描对强风暴定量降水预报的同化影响：热力学检索方法推动数据同化实验的证据
DOI：
10.1002/qj.3548
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
S. Suzuki
中科院分区：
文献类型：
--
作者：
S. Shimizu;K. Iwanami and R. Kato; N. Sakurai; T. Maesaka; K. Kieda; Y. Shusse; S. Suzuki
用Nudging资料同化方法研究了高时间体积扫描资料(1min)对强风暴极短期(1 h以内)定量降水预报的同化作用。这项研究调查了(A)两个观测参数(使用传统技术反演的位温和从反射率观测中获得的伪水汽)对同化的影响，(B)对三维雷达观测的时间分辨率的敏感性，以及(C)同化方法(在单个时间重新初始化或在20 分钟内连续轻推)对2013年9月2日在日本小谷市附近观测到的龙卷风风暴的可预报性。我们的结果表明：(A)在评估期的前30 分钟(总共50 分钟)，伪水汽和位温扰动的资料同化的贡献最大，(B)更好的时间分辨率提供了更好的总体预报，以及(C)一种轻推方案在前30 分钟提供更好的预报。在评估期的后40 分钟，我们的结果显示出比传统的基于外推的现在预报更好的预测性。因此，通过1分钟的体积扫描确定的与水汽和位势温度的数据同化，有可能在强降雨强度(>；20 mm/h)的极短期QPF(30 分钟内)的情况下扩大云尺度的可预报性。
The assimilation impact of high‐temporal volume scan data (1 min) on very‐short‐range (within 1 h) quantitative precipitation forecasts (QPFs) of a severe storm was investigated using a nudging data assimilation method. This study investigated (a) the assimilation impact of two observational parameters (potential temperature, retrieved using a traditional technique and pseudo‐water vapour, obtained from reflectivity observations), (b) the sensitivity to the temporal resolution of three‐dimensional radar observations, and (c) the assimilation method (re‐initialization at a single time or sequential nudging over 20 min), regarding the predictability of a tornadic storm observed on 2 September 2013 around Koshigaya City, Japan. Our results indicate that (a) data assimilation of both pseudo‐water vapour and potential temperature perturbation demonstrated the highest contribution for up to the first 30 min of the evaluation period (50 min in total), (b) finer temporal resolution provided a better forecast overall, and (c) a nudging scheme provided a better forecast in the first 30 min. Our results showed better predictability than traditional extrapolation‐based nowcasts in the latter 40 min of the evaluation period. The data assimilation with water vapour and potential temperature, determined from a 1 min volume scan, therefore has the potential to extend the cloud‐scale predictability in strong rainfall intensity situations (>20 mm/h) of very‐short‐range QPFs (within 30 min).