ISSN 1000-0526
CN 11-2282/P
CN 11-2282/P
Archive > Volume 49 Issue 8 > 2023,49(8):915-931. DOI:10.7519/j.issn.1000-0526.2023.060401 Prev Next
Sensitivity Experiments of Half-Hourly Assimilation of Multi-Source Data in One Regional Persistent Rainstorm Process
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Abstract:
The hourly and half-hourly data assimilation sensitivity experiments for one regional persistent rainstorm process in southern Shandong from August 13 to 14 2020 are carried out using the half-hourly update and prediction system based on WRF with the purpose of exploring the application of high frequency data assimilation. The half-hourly data assimilation experiments include three assimilation schemes: assimilating of the automatic weather station (AWS) data and the aircraft meteorological data relay (AMDAR) data at the half-hour frequency, and “rejecting” one of them respectively. The results show that the half-hourly cooperative assimilation experiment of AWS observation and AMDAR data can significantly improve the numerical prediction of 24 h accumulated precipitation and 1 h short-term severe precipitation during this persistent rainstorm relative to the hourly assimilation experiment. This indicates that increasing the assimilation frequency to increase the utilization of high-frequency data has a positive effect on the numerical prediction. In the process of half-hourly data assimilation, the experiment of assimilating AWS data and AMDAR data at the same time is more accurate than the experiment of “rejecting” one of them respectively. The result of assimilation experiment “rejecting” AMDAR data is worse than that of “rejecting” AWS data, indicating that the assimilation of AMDAR data plays a more import role than that of AWS data in half-hourly assimilation. The improvement of initial field by rapid updating cyclic assimilation is a process of gradual adjustment. The experiments with different assimilation data and frequencies have different effects on the analysis field. The initial field of half-hourly assimilation experiment of collaborative assimilating AWS data and AMDAR data is the closest to the observation. The different positions of the high temperature and high humidity area of the ground element field relative to the convergence line under different assimilation schemes, and the different strength and configuration of high-altitude cold and warm air lead to different movement directions of the squall line system, which is the main reason for the great difference of precipitation areas in each experiment. However, the location difference of squall line system leads to the different degree of integration with the newborn system in the warm and humid airflow in the southwest, resulting in the difference of precipitation intensity in the future.
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