Impact of WIVERN Horizontal Line-Of-Sight Wind Profiles on the Global NWP model of Météo-France Using an Ensemble Data Assimilation Method
In 2021, the WIVERN mission was selected by ESA to enter in phase 0 and compete to be the 11th Earth Explorer mission. With its dual-polarization Doppler conically scanning W band radar, WIVERN will be the first space-based mission to provide in-cloud winds at a high vertical resolution of 650 m sampling a broad swath of width 800 km.
To assess the benefits brought by the assimilation of WIVERN HLOS wind profiles, we employ the Ensemble Data Assimilation (EDA) system of ARPEGE (AEARP), which consists of 50 members each one running a four-dimensional variational (4D-Var) data assimilation system at low resolution. In this methodology, the benefits of adding WIVERN HLOS wind observations to the current observing system are measured by their capacity to reduce the EDA spread at the analysis time and at other forecast lead times. This methodology was initially proposed by Tan et al. (2007) for the preparation of the Aeolus mission, then by Harnisch et al. (2013) to assess the impact of the number of GNSS-RO measurements, and more recently by Lean et al. (2021) to prepare a future constellation of small satellites carrying microwave sounders.
In this presentation, we will first present the methodology. Next, the impact of the assimilation of WIVERN observations, in addition to the current existing observation system, will be shown in reducing the spread of the ARPEGE EDA. In particular, we will show the impact of the assimilation of WIVERN with and without AEOLUS. Finally, the impact of different EDA setups, such as quality control and observation error, will be studied.
