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李梦迪, 戚友存, 张哲, 等. 2022. 基于雷达—雨量计降水融合方法提高极端降水监测能力[J]. 大气科学, 46(6): 1523−1542. doi: 10.3878/j.issn.1006-9895.2201.21201
引用本文: 李梦迪, 戚友存, 张哲, 等. 2022. 基于雷达—雨量计降水融合方法提高极端降水监测能力[J]. 大气科学, 46(6): 1523−1542. doi: 10.3878/j.issn.1006-9895.2201.21201
LI Mengdi, QI Youcun, ZHANG Zhe, et al. 2022. Improving the Detection Performance of Extreme Precipitation Observations Using a Radar–Gauge Merging Algorithm [J]. Chinese Journal of Atmospheric Sciences (in Chinese), 46(6): 1523−1542. doi: 10.3878/j.issn.1006-9895.2201.21201
Citation: LI Mengdi, QI Youcun, ZHANG Zhe, et al. 2022. Improving the Detection Performance of Extreme Precipitation Observations Using a Radar–Gauge Merging Algorithm [J]. Chinese Journal of Atmospheric Sciences (in Chinese), 46(6): 1523−1542. doi: 10.3878/j.issn.1006-9895.2201.21201

基于雷达—雨量计降水融合方法提高极端降水监测能力

Improving the Detection Performance of Extreme Precipitation Observations Using a Radar–Gauge Merging Algorithm

  • 摘要: 高时空分辨率、高精度的降水产品对于极端降水的监测以及防灾减灾具有重要意义。地面雨量计提供点尺度降水精确观测,但无法精细化捕捉对流性强降水的空间分布。雷达观测可以精细地刻画降水的空间分布特征,但雷达定量估计降水(QPE,quantitative precipitation estimation)产品估测精度易受雷达观测偏差和ZR(雷达反射率—降水率)关系等因素影响。因此,本文开展高时空分辨率的雷达—雨量计降水融合算法研究,集成雨量计观测和雷达定量估计降水产品各自的优点。该算法主要步骤包括:雨量站观测数据格点化、局地雨量计订正雷达QPE和雷达—雨量计降水融合三个部分。首先利用克里金插值方法,对雨量站观测的降水进行插值,得到格点降水信息;再通过局地雨量计订正方法系统性地订正雷达QPE产品,以提高雷达QPE产品精度;最后,结合降水类型,通过雷达—雨量计降水融合算法,产生高时空分辨率、高精度的雷达—雨量计降水融合产品。通过郑州“21·7”暴雨、台风“烟花”和2021年8月随州暴雨三个典型的极端降水个例,对雷达—雨量计降水融合算法产生的雷达—雨量计降水融合产品进行了系统地评估和分析。结果表明,在不同的极端降水个例和不同的降水时段,雷达—雨量计降水融合产品精度上优于雷达QPE产品,且在降水的空间分布上较雨量站观测格点插值产品更能精细地刻画降水的结构特征。表明算法得到的雷达—雨量计降水融合产品的准确性较高,对极端降水有较好地捕捉和监测能力。

     

    Abstract: Precipitation products with high spatial and temporal resolution and high accuracy are crucial for monitoring extreme precipitation events as well as preventing and mitigating disasters. Gauge station observations provide accurate point-scale precipitation but are insufficient for finely capturing spatial information on heavy precipitation induced by severe convection. Radar scanning can provide accurate precipitation information with high spatial and temporal resolution, but the accuracy of radar QPE (quantitative precipitation estimation) is vulnerable to various factors, such as observation accuracy and ZR (radar reflectivity factor Z and rainfall rate R) relationship. Therefore, a radar–gauge merging algorithm is proposed in this paper to combine the advantages of gauge station observations and radar QPE. The algorithm includes three steps: Kriging interpolations of precipitation, LGC (local gauge-corrected) radar QPE, and radar–gauge merging QPE. First, the precipitation interpolation fields are obtained by the Kriging method based on the regional station observations. Subsequently, based on the LGC method, the accuracy of the radar QPE is improved by making systematic corrections. Finally, combined with the precipitation type, the radar–gauge merging QPE with high spatial and temporal resolution and high accuracy is produced by the radar–gauge merging algorithm. Three extreme precipitation events, namely, the 21·7 extreme precipitation in Zhengzhou, typhoon In-Fa, and the extreme precipitation in Suizhou in August 2021, are used to evaluate the performance of the radar–gauge merging algorithm. Results show that the new radar–gauge merging QPE outperforms the radar QPE product in terms of accuracy and characterizes the precipitation structure more finely than the Kriging interpolations of the gauge station observations in terms of the spatial distribution and time periods of the different extreme precipitation events. These results indicate the high accuracy and stability of the new radar–gauge merging algorithm and its ability to capture the distribution of extreme precipitation events.

     

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