Lidar observations of low-level wind reversals over the Gulf of Lion and characterization of their impact on the water vapour variability

Paolo Di Girolamo (1) , Cyrille Flamant (2) , Marco Cacciani (3) , Donato Summa (1) , Dario Stelitano (4) , Ignazio Mancini (1) , Evelyne Richard (5) , Véronique Ducrocq (6) , Mathieu Nuret (6) , Frédérique Saïd (5)

1 Difa - Dipartimento di Ingegneria e Fisica dell'Ambiente [Potenza]
2 TROPO - LATMOS
3 Dipartimento di Fisica [Roma La Sapienza]
4 UNIBAS - Università degli studi della Basilicata [Potenza]
5 LAERO - Laboratoire d'aérologie
6 CNRM - Centre national de recherches météorologiques

Water vapour measurements from a ground-based Raman lidar and an airborne differential absorption lidar, complemented by high resolution numerical simulations from two mesoscale models (Arome-WMED and MESO-NH), are considered to investigate transition events from Mistral/Tramontane to southerly marine flow taking place over the Gulf of Lion in Southern France in the time frame September-October 2012, during the Hydrological Cycle in the Mediterranean Experiment (HyMeX) Special Observation Period 1 (SOP1). Low-level wind reversals associated with these transitions are found to have a strong impact on water vapour transport, leading to a large variability of the water vapour vertical and horizontal distribution. The high spatial and temporal resolution of the lidar data allow to monitor the time evolution of the three-dimensional water vapour field during these transitions from predominantly northerly Mistral/Tramontane flow to a predominantly southerly flow, allowing to identify the quite sharp separation between these flows, which is also quite well captured by the mesoscale models.

Domains: Atmospheric and Oceanic Physics [physics.ao-ph]; Ocean, Atmosphere

Paolo Di Girolamo, Cyrille Flamant, Marco Cacciani, Donato Summa, Dario Stelitano, et al.. Lidar observations of low-level wind reversals over the Gulf of Lion and characterization of their impact on the water vapour variability. EPJ Web of Conferences, 2016, The 27th International Laser Radar Conference (ILRC 27), 119, pp.15002. ⟨10.1051/epjconf/201611915002⟩. ⟨insu-01176549⟩