Overview of the Raman lidar measurements in the frame of the HyMeX-SOP 1

International audienceThe University of BASILicata ground-based Raman Lidar system (BASIL) was deployed inCandillargues (Southern France, Lat: 43°37' N, Long: 4° 4' E) in the frame of theHydrological Cycle in the Mediterranean Experiment - HyMeX. Within this experiment amajor field campaign (Special Observation Period 1-SOP1, September to November 2012)took place over the North-western Mediterranean Sea and its surrounding coastal regions inFrance, Italy and Spain, with a specific focus on the study of heavy precipitation and flashfloodevents. During HyMeX-SOP1, BASIL operated between 5 September and 5 November2012, collecting more than 600 hours of measurements, distributed over 51 measurementdays and 19 intensive observation periods (IOPs).The major feature of BASIL is represented by its capability to perform high-resolution andaccurate measurements of atmospheric temperature and water vapour, both in daytime andnight-time, based on the application of the rotational and vibrational Raman lidar techniquesin the UV. This makes it an ideal tool for the characterization of the water vapour inflow inSouthern France, which is important piece of information to improve the comprehension andforecasting capabilities of heavy precipitations in the North-western Mediterranean basin.Besides temperature and water vapour, BASIL also provides measurements of the particle(aerosol/cloud) backscattering coefficient at 355, 532 and 1064 nm, of the particle extinctioncoefficient at 355 and 532 nm and of particle depolarization at 355 and 532 nm.Measurements from this field deployment are illustrated and discussed in this presentation.Specifically, we report on results concerning a water vapour inter-comparison effort,involving the ground-based lidar BASIL, the airborne water vapour lidar LEANDRE 2 flyingon board the ATR42, as well as additional water vapour sensors on-site (radiosondes, GPStomography, aircraft in-situ sensors, microwave radiometers). The main objective of thisinter-comparison is providing accurate error estimates for these sensors. This effort benefitsfrom the few dedicated ATR42 flights in the frame of the EUFAR Project “WaLiTemp”. In thepresent work our attention was focused on two specific case studies: 13 September and 2October in the altitude region 0.5 – 5.5 km. Comparisons between BASIL and LEANDRE 2indicate a mean relative bias between the two sensors of 6.5%, while comparisons betweenBASIL and LEANDRE 2 vs. the radiosondes indicate a bias of 2.6 and -3.5 %, respectively.Specific attention will also be dedicated to the WALI/BASIL inter-comparison effort whichtook place in Candillargues on 30 October 2012. Specific results from this inter-comparisoneffort will be illustrated and discussed at the Workshop.Measurements from BASIL have also been considered to characterize Planetary BoundaryLayer moisture turbulence processes. In this respect a spectral analysis was carried out on thehigh-resolution water vapour mixing ratio data for specific case studies. Results from thesefurther study will also be illustrated at the Workshop