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Observation system experiments using summer intensive upper-air observation for Changma rainfall events of South Korea during ProbeX-2014

H.-W. Choi, S.-H Won, K.-H. Kim, Y.-H. Kim, C.-H. Cho (National Institute of Meteorological Research)

Time and space-based high resolution data are important factors affecting improvement of numerical predictability. The National Institute of Meteorological Research(NIMR) has performed observation program for improvement of predictability. As part of this observation program, summer intensive observation program(ProbeX-2014) was performed to improve the short-term prediction and research on physical process for Changma rainfall events at Boseong, Changwon and Gosan be located in southern region in South Korea during 30 days(from 16 June to 15 July 2014).

In order to examine the effects of additional upper-air observation on the numerical weather prediction, Observation System Experiments (OSEs) using Unified Model (UM 12km L70) and Four-Dimensional Variational system Data Assimilation (4DVAR) system are carried out for two rainfall events on 3 and 6 June 2014. Control experiment (CNTL) used only conventional observation and the other experiment (EXP) used conventional observation and summer intensive observation data. Besides, additional experiments using different time-interval(6h, and 12h) data are performed.

Distribution of the 12-hours accumulated precipitation of the EXP is improved at the southern region of Korean peninsula. Moreover, Equitable Threat Scores (ETS) of the EXP are about 27.4% and 2.3% higher than CNTL for two rainfall events, respectively. The results indicate that summer intensive observation data have positive impact on short prediction for Changma rainfall events.