[A-AS03] Advances in Tropical Cyclone Research: Past, Present, and Future

[AAS03-03] Impact of Aeolus DWL data assimilation in the JMA’s global data assimilation system on forecasting skills for typhoons

*Izumi Okabe¹, Kozo OKAMOTO¹ (1.Meteorological Research Institute of Japan Meteorological Agency)

Keywords:Satellite data, Data assimilation, Typhoon

European Space Agency’s (ESA’s) Earth Explorer, Aeolus, was launched into space on 22 August 2018. The horizontal line of sight (HLOS) wind data from Aeolus Doppler Wind Lidar (DWL) is available from the ESA Earth Online Portal. The DWL provides wind profile observations with high vertical resolution (0.5-2.0 m) in clear air, inside thin clouds and aerosol layers and on top of thick clouds globally. Assimilation experiments of this HLOS data were conducted using JMA’s global data assimilation (DA) system and the global spectral model (GSM) at a horizontal resolution of 20km and vertical layers of 100. The experiment term is from July to October 2020. The result of the assimilation experiments showed positive impacts of Aeolus HLOS wind data on forecasting scores (global average of root mean square errors, etc.) of not only wind speed but also geopotential height, temperature and specific humidity. Improvement of typhoon track forecasting after about three days was found suggesting the improved environment forecasting. During the experiment term, Aeolus observed horizontal wind shears around some typhoons. The Aeolus assimilation seemed to intensify the divergence over the top of typhoons. The details of assessment and assimilation experiments will be shown in the presentation.