Latent flow measurement by Wind Lidar and Raman Lidar during WaLiNeas campaign

A network of water vapor Raman lidars  WaLiNeas (Lidar Network Assimilation) for improving heavy precipitation forecasting in the Mediterranean Sea has been designed among with the aim of providing water vapor measurements with high spatial-temporal resolution and accuracy, in order to be assimilated into AROME mesoscale models using a four-dimensional ensemble-variational approach with 15-min updates. The CONCERNIG Lidar from University of Basilicata and a Wind Lidar form CNR–IMAA are co-located in the University of Toulone between October 2022 and January 2023 in order to reach the campaign objective. For this scope a of vertical profiles of latent heat flux were obtained  as a  Covariance matrices from vertical wind component (w') and mixing ratio (q') are estimated as a retrieval of a Wind Lidar and Raman Lidar UV respectively.

In this way, a time series of vertical wind profiles from the selected case (31 Oct to 03 Nov) are computed. with temporal resolution Δt = 15 min and vertical resolution Δz = 90 m.  The specific humidity flux < w’ · q’>  [g/kg · m/s] is converted into the flux of latent heat (W/m²) by multiplication with the air density ρ obtained from the radiosonde and the latent heat of vaporization of water Lv. A flux comparison with ground-based water vapour Raman and wind lidar shows agreement within the instruments and the results will be presented during the conference