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Keynote F. Lohou / M. Lothon

Keynote addresses will be delivered to set the underlying tone and summarize the core message. These speeches will be done by specialists from laboratories and international companies recognized for their expertise in the field.

Study of the atmospheric turbulence based on the observations at the P2OA
Marie Lothon & Fabienne Lohou
LAERO, Toulouse University, France


The Pyrenean Platform for the Observation of the Atmosphere (P2OA) is composed of an altitude platform and a plain site, 28 km apart as a crow flies. The environmental platform, at the top of the Pic du Midi de Bigorre (2870 m.a.s.l.), gathers the instrumentation for aerosols, greenhouse and reactive gazes, whereas the Centre de Recherches Atmospherique (600 m.a.s.l.) located on the Lannemezan Plateau is mainly devoted to the instrumentation for atmospheric dynamics. Both sites are also instrumented for atmospheric electricity studies. Besides long term measurements, the P2OA hosts limited duration field campaigns. These campaigns can contribute to the study of atmospheric processes, to the validation of new instrumentations or to any other action which could take advantage of the permanent observations.

After a rapid presentation of the P2OA, its instrumentation set and its missions, we will focus on the permanent measurements, and hosted field campaigns BLLAST -Boundary Layer Late Afternoon and sunset Transition- and MOSAI -Model and Observation for surface Atmosphere Interactions- which allow the study of the turbulence in the low layer of the atmosphere. The instrumentation is either in-situ measurements acquired at high-frequency at surface with ground station or in the low atmosphere with instrumented aircraft or unmanned aerial vehicle, or remote sensing measurements with wind profilers.  We will come back on the turbulence characteristics and its diurnal cycle in the atmospheric boundary layer and we will show how the combination of those measurements allow us to characterize the turbulence within the atmospheric boundary layer, which is governed by the interaction between surface and atmosphere, with either thermal or dynamical source of turbulence.

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Marie Lothon is a research scientist at CNRS working on the boundary layer dynamics with in situ or remote sensing observations. She is PI of the wind profiler observations at P2OA, scientist lead of the Centre de Recherches Atmosphériques, and co-coordinator of the P2OA. She initiated and coordinated the BLLAST (Boundary Layer Late Afternoon and Sunset Transition) project and field campaign with Fabienne Lohou, focused on the decaying convective boundary layer during the late afternoon transition. She also was involved in several aircraft field campaigns in several international programmes (AMMA, EUREC4A, LIAISE), for her expertise in aircraft atmospheric turbulence measurements.
 
Fabienne Lohou is a research expert in land-atmosphere interaction processes, and on surface turbulence fluxes measurements. At P2OA, she is in charge of the 60-m instrumented tower for meteorological and surface energy balance monitoring. She is the coordinator of the flux working group of ACTRIS-FR Reasearch Infrastructure. She was involved in several projects and field campaigns on atmospheric boudary layer processes and turbulence (AMMA, BLLAST, DACCIWA, LIAISE). Currently, she coordinates with Marie Lothon the MOSAI (Model and Observation for Surface-Atmosphere Interactions) project which aims at improving the evaluation and representation of the land-atmosphere interaction over heterogeneous surfaces in the numerical earth system models.