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 (1) , Evelyne Richard (4) , Veronique Ducrocq (5) , Nadia Fourrié (5) , Frédérique Saïd (4)

1 Scuola di Ingegneria [Potenza]
2 TROPO - LATMOS
3 Dipartimento di Fisica [Roma La Sapienza]
4 LAERO - Laboratoire d'aérologie
5 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: Physics [physics]; Physics [physics]; Atmospheric and Oceanic Physics [physics.ao-ph]

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. International Radiation Symposium (IRC/IAMAS), Apr 2016, Auckland, New Zealand. pp.080001, ⟨10.1063/1.4975532⟩. ⟨insu-01501821⟩