5A.3 Observation impact in East Asia and western North Pacific regions using WRF-FSO system

Jung, Byoung-Joo, Korea Institute of Atmospheric Prediction Systems, Hyun Mee Kim, Yonsei University, Thomas Auligne, Xin Zhang, Xiaoyan Zhang, and Xiang-Yu Huang, National Center for Atmospheric Research

In this study, the adjoint-based observation impact on the short-range forecast over East Asia and the western North Pacific region is evaluated using WRF Forecast Sensitivity to Observations (FSO) system with 3 dimensional variational (3DVAR) data assimilation system. While AMSU-A radiance observation has the greatest total impact, the wind from conventional observation has the greatest impact per observation number. For each observation type, the total impact is greatest for radiosonde and each AMSU-A satellite, followed by SYNOP, QSCAT, GEOAMV, and METAR. For several analysis times for typhoons Sinlaku (200813) and Jangmi (200815), the dropsonde soundings near the typhoon have a similar or greater observation impact, compared to the routine radiosonde soundings. The preliminary result of sensitivity to error covariance parameters is also presented. The observation impact from the observing system experiments (OSEs) is qualitatively similar to that from the adjoint method for major observation types. This study confirms that the radiosonde observations provide primary information on the atmospheric state as in-situ observations, and the satellite radiances are an essential component of atmospheric observing systems.