P-35

Impact of hybrid-4DVar at KMA

Hyun-Cheol Shin (KMA), Adam Clayton (Met Office), Joo-hyung Son (KMA), Sang-Won Joo (KMA), Young-Hwa Kim (KMA)

The performance of KMA's NWP system has greatly improved since the introduction of the UK Met Office's Unified Model (UM) system in 2010.

In particular, the use of the Met Office Observation Processing System (OPS) and 4DVar in the global forecasting system enabled a substantial increase in the number of assimilated observations and significant improvements in their usage, leading to reliable forecasts. In 2013, the hybrid-4DVar system is implemented in cooperation with the Met Office using the ensemble covariance generated from a 24-member global EPS (MOGREPS) at KMA. The upgrade to hybrid-4DVar lead to overall improvements in verification scores. A selection of these scores will be presented, along with some examples of impacts on typhoon forecasts.