Preprints
https://doi.org/10.5194/amt-2022-341
https://doi.org/10.5194/amt-2022-341
 
05 Jan 2023
05 Jan 2023
Status: this preprint is currently under review for the journal AMT.

The impacts of assimilating Aeolus horizontal line-of-sight winds on numerical predictions of Hurricane Ida (2021) and a mesoscale convective system over the Atlantic Ocean

Chengfeng Feng and Zhaoxia Pu Chengfeng Feng and Zhaoxia Pu
  • Department of Atmospheric Sciences, University of Utah, Salt Lake City, 84112, United States

Abstract. On 22 August 2018, the European Space Agency (ESA) launched the first spaceborne wind lidar, the Aeolus satellite, measuring horizontal line-of-sight (HLOS) winds globally. The assimilation of Aeolus HLOS winds has been proven to improve numerical weather predictions (NWPs). Still, its influences on forecasts of tropical cyclones (TCs) and tropical convective systems have yet to be examined in detail. This study investigates the impacts of assimilating Aeolus HLOS winds on the analysis and forecasts of Hurricane Ida (2021) and a mesoscale convective system (MCS) embedded in an African easterly wave (AEW) over the Atlantic Ocean (AO) with the mesoscale community Weather Research and Forecasting (WRF) model and the NCEP-GSI based three-dimensional ensemble-variational (3DEnVAR) hybrid data assimilation (DA) system. Mie-cloudy and Rayleigh-clear winds are assimilated. The results for Ida (2021) show that assimilating Aeolus HLOS winds leads to better track predictions. The intensity forecasts are improved in some cases, even with limited coverage of Aeolus HLOS winds within the inner core region of Ida (2021). In addition, the structure of heavy precipitation associated with Ida (2021) is refined after assimilation of Aeolus HLOS winds. Further diagnosis demonstrates that the improved intensity and precipitation forecasts result from enhanced divergence in the upper level of the troposphere after assimilation of Aeolus HLOS winds. Additional results from the MCS associated with an AEW indicate that assimilating Aeolus HLOS winds enhances forecasts of its precipitation structure and the associated low-level divergence. In short, this study demonstrates the potential of assimilation of Aeolus HLOS winds to improve forecasts for TCs and tropical convective systems.

Chengfeng Feng and Zhaoxia Pu

Status: open (until 06 Mar 2023)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse

Chengfeng Feng and Zhaoxia Pu

Chengfeng Feng and Zhaoxia Pu

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Short summary
This study demonstrates the positive impacts of assimilating Aeolus Mie-cloudy and Rayleigh-clear near-real-time horizontal line-of-sight winds on the analysis and forecasts of Hurricane Ida (2021) and a mesoscale convective system associated with an African easterly wave with the mesoscale community Weather Research and Forecasting model and NCEP Gridpoint Statistical Interpolation-based three-dimensional ensemble-variational hybrid data assimilation system.