1 METEO FRANCE/CNRM, Toulouse, France. 2 METEO FRANCE/ENM, Toulouse, France. 3 ENAC, Toulouse, France. UAS for Meteorological and Atmospheric Studies G. Roberts 1 , G. Cayez 1,2 , F. Lavie 1 , D. Tzanos 1 , J.L. Brenguier 1 , C.Ronfle-Nadaud 3 , G. Hattenberger 3 , M. Bronz 3 Abstract The National Center for Meteorological Research (CNRM-GAME, Toulouse, France) conducted UAS flights in Southern France on two UAS platforms (mini and mid-size UAS) to demonstrate their feasibility for meteorological and atmospheric studies. The UAS were equipped with meteorological and aerosol sensors as well as a data acquisision system. The meteorological sensors (temperature, relative humidty and pressure) were tested in different housings to assess the optimum design and placement of the sensors. In addition, a standard radiosonde device attached to the aircraft fuselage and balloon launches served as a reference. We found that convective and radiative components generated biases in the meteorological measurements. Aerosol concentrations and particle size distribution were also measured by optical counter and compared for two different inlet designs. Introduction : (Unmanned Aerial System) UAS are useful tools to study the atmosphere in places dangerous for aircrafts : hurricanes, fogs, polar research,... UAS performance and cost comparisons COST ES0802 I UAS starting integration into studies of climate change and sustainable development. I COST Action coordinates research on using UAS as a cost-efficient, trans-boundary method for the monitoring of the atmospheric boundary layer. I UAS close observational gaps between ground-based and satellite-based measurements. I In-situ observations ultimately improve numerical weather models and climate simulation. I UAS systems come in different sizes, complexity and equipped with different instrumentation. I The COST Action promotes the conception and further development of UAS for use in atmospheric research programs. I The networking activities have established a foundation at the European level for the coordination of scientific, technical and legal aspects related to viable operation of UAS. http://bllast.sedoo.fr/ Photo campagne BLLAST: Marie LOTHON VOLTIGE : (Vecteur d’Observation de La Troposph` ere pour l’investigation et la Gestion de l’Environnement) I Cloud microphysics of fog events ; I Structure of lower troposphere (inversion height, atmospheric stability). I evolution of boundary layer height ; I radiative fluxes and albedo ; I turbulent kinetic energy ; I Few in-situ measurements of the vertical structure of fog ; I Most fog studies are constrained to ground-based observations and remote sensing ; I Payload adapted for ultra-light UAS airframe for a specific measurement. Liquid Water Content Pyranometer Pressure,Temperature, and Relative Humidity turbulence probe UAS at CNRM Several types of vectors : UAS Funjet Performances : I Total weight : 850 g; I Endurance : ∼ 20 min, electric ; I Ceiling : Tested to ∼ 2,1 km. UAS Easystar Performances : I Total weight : 1000 g; I Endurance : ∼ 35 min, electric ; I Ceiling : Tested to ∼ 1,6 km. UAS Avion Jaune Performances : I Total weight : 20 kg; I Endurance : ∼ 8 h, thermic ; I Ceiling : ∼ 4 km. UAS navigation : General principle of an autopilot Paparazzi man-machine interface The UAS for VOLTIGE are ultra-light model airframes equipped with a Paparazzi autonomous navigation system developped by ENAC. Meteorological instrumentation : Temperature, Pressure, Relative Humidity Sensors for VOLTIGE operations Data acquisition system The goal is to design meteorological sensors which conform to standards mandated by Meteo-France. These sensors are used to derive atmospheric parameters including potential temperature, stability, boundary layer height, and lifting condensation level. Lannemezan site with two mast for meteorological insitu mesures Easystar under rain and snow ← We have tested the drones under adverse weather conditions (rain, snow, wind) and in clouds). Acknowledgments I M. Gavart, M. Joanne (Avion Jaune System) ; I G.Hattenberger, M. Bronz, M. Gorraz, A. Bustico (ENAC). I F. Lohou et M. Lothon (CRA Lannemezan); I S. Defoy (Meteo-France). Mesurements artefacts Hysteresis : view on the UAV helical trajectory Temperature profile and cumulative aerosol profile ← Problem of hysteresis was noticed on the temperature profile. Sensor bias : Mini-Temperature probe data show → oscillations. As the drone turns, it might be caused by : I variation of solar heating on probe ; I variation of Solar heating on drone ; I variation of relative wind. A poorly designed probe exacerbates the oscillation phenomenon Proper probe placement and design is important to ensure viable atmospheric measurements. Cloud droplets, variations in wind speed, even biases by drone’s airframe can bias the measurements. Table of probes designed and tested reverse-flow metallic probe helical probe helical probe with double wall open probe ← Three kinds of temperature probe have been created and tested : I reverse-flow probe ; I helical probe (with or without double wall) ; I open cylindrical probe. Drones flew hypodromes trajectories around the Lannemezan masts in order to make some comparisons between insitu mast measures and the drone probes measures Sensor bias of temperature is seen : 0.7 ˚ C for helical probe ; 3.5 ˚ C for reverse flow probe ← Comparison stationary / flight OPC concentrations > 1.5 enhancement during flight using non-optimised inlet inlet flow sub-isokinetic / no shroud and no iso-axial, important to design proper aerosol inlet and match flows Use of the video in flight Temperature and RH Profiles ← Campaign in Landes in Febrary 12th-14th : ∼ 20 flights and sensor tests