A network of water vapor Raman lidars for improving heavy precipitation forecasting in southern France: introducing the WaLiNeAs initiative

Abstract

Extreme heavy precipitation events (HPEs) pose a threat to human life but remain difficult to predict because of the lack of adequate high frequency and high-resolution water vapor (WV) observations in the low troposphere (below 3 km). To fill this observational gap, we aim at implementing an integrated prediction tool, coupling network measurements of WV profiles, and a numerical weather prediction model to precisely estimate the amount, timing, and location of rainfall associated with HPEs in southern France (struck by ~ 7 HPEs per year on average during the fall). The Water vapor Lidar Network Assimilation (WaLiNeAs) project will deploy a network of 6 autonomous Raman WV lidars around the Western Mediterranean to provide measurements with high vertical resolution and accuracy to be assimilated in the French Application of Research to Operations at Mesoscale (AROME-France) model, using a four-dimensional ensemble-variational approach with 15-min updates. This integrated prediction tool is expected to enhance the model capability for kilometer-scale prediction of HPEs over southern France up to 48 h in advance. The field campaign is scheduled to start early September 2022, to cover the period most propitious to heavy precipitation events in southern France. The Raman WV lidar network will be operated by a consortium of French, German, Italian, and Spanish research groups. This project will lead to recommendations on the lidar data processing for future operational exploitation in numerical weather prediction (NWP) systems.

Extreme temperature events monitored by Raman lidar: Consistency and complementarity with spaceborne observations and modelling

“…The ability of WALI to continuously trace the diurnal cycle of the PBL fills an observational gap and allows (i) to complement spaceborne instruments like IASI and (ii) to provide a strong constraint in the lower layers for meteorological models; in particular during ETEs. This capacity could benefit future spaceborne missions such as IASI-NG (Crevoisier et al, 2014) and the new generation of numerical forecast models (Brousseau et al, 2016) through data assimilation and parameterization validation (Flamant et al, 2021).…”

“…It can perform continuous measurements autonomously with low power consumption (<1 kW) and reliable stability. Currently devoted to aerosol and meteorological measurements during instrumental field campaigns (Chazette, Totems, et al, 2016; Totems et al, 2019), this lidar architecture could be employed for autonomous ground‐based meteorological lidar stations (Flamant et al, 2021).…”

Impact of assimilating lidar water vapour and temperature profiles with a hybrid ensemble transform Kalman filter: Three‐dimensional variational analysis on the convection‐permitting scale

“…Several DA research studies have been conducted using the water vapour lidar data which had created a spatial impact over a large area (Grzeschik et al ., 2008; Leuenberger et al ., 2020; Yoshida et al ., 2020). A new initiative, Water vapour Lidar Network Assimilation (WaLiNeAs), to assimilate high‐resolution vertical water vapour profile data from a network of six water vapour lidar systems is planned to start in early September 2022 in the western Mediterranean (Flamant et al ., 2021). Lidar network DA promises excellent potential for future operational forecasting.…”

Atmospheric Thermodynamic Profiling through the Use of a Micro-Pulse Raman Lidar System: Introducing the Compact Raman Lidar MARCO

“…Measurements from this system, with a specific focus on water vapor profiles, are also illustrated and discussed in the paper, where an accurate assessment of measurement performance is also provided. The prototype system, named MARCO (Micro-pulse Atmospheric Optical Radar for Climate and Weather Observations), was successfully deployed in Camargue (Port Saint Louis) and has continuously operated, starting in mid-October 2022, over a period of more than 11 months (up to now) in the frame of the Water vapor Lidar Network Assimilation (WaLiNeAs) project [27].…”