Observation of low-level wind reversals in the Gulf of Lion area and their impact on the water vapour distribution and variability
Abstract
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), have been considered to investigate
three transition events from Mistral/Tramontane to southerly marine flow taking place in
the Gulf of Lion area in the time frame September-October 2012, during the Hydrological
Cycle in the Mediterranean Experiment Special Observation Period 1. 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
distributions. The high spatial and temporal resolutions of the lidar data allow monitoring
the time evolution of the three-dimensional water vapour field during these transitions from
predominantly northerly Mistral/Tramontane flow to a predominantly southerly flow,
permitting to identify the quite sharp separation between these flows, which is also well
captured by the mesoscale models. Water vapour measurements from the ground-based
lidar are complemented by particle backscatter measurements from the same system, which
allow also revealing the significant variability in the aerosol and cloud fields associated with
these transition events. Results will be illustrated and discussed at the Conference.
Origin : Files produced by the author(s)