Application of High Spatial and Temporal Resolution Nowcasting in Korea

The accuracy of extrapolation has better performance than that of numerical model in 3 hours. However, its skill dramatically decreases as forecast time increases especially after 3 hours. Ensemble forecasts with different initial conditions are examined to mitigate this property in this study. The effect of the uncertainty of initial conditions on the forecasts are used as ensemble members. It is expected that ensemble forecasts would help forecasters to make decisions by providing the probabilities of severe weather compared to deterministic maps from conventional deterministic nowcasts.

The comparisons of statistical scores between deterministic forecasts and ensemble nowcasting was performed for evaluating the performances. KOrea NOwcasting system (KONOS) operated in Weather Radar Center (WRC) of the Korea Meteorological Administration (KMA) was used as the deterministic forecasts. Ensemble forecasts obtained from Short-Term Ensemble Prediction System (STEPS) developed in Bureau of Meteorology of Australia was used. In short, KONOS system includes the calculations of motion vectors to extrapolate using Vibrational Echo Track method (VET). On the contrary, STEPS obtained motion vectors by applying the optical flow method. In STEPS, each ensemble member obtains a different field of motion vectors using different initial conditions. The performance will be quantitatively examined using the high spatial and temporal resolution data of radar reflectivity and Radar-AWS Rainrate (RAR) in May to July 2016.

 

 

Acknowledgment
This work was funded by the Korea Meteorological Industry Promotion Agency under Grant KMIPA 2015-5060.
This work was financially supported by the BK21 plus Project of the Graduate School of Earth Environmental Hazard System.