Atmospheric aerosols play a key role on climate balance (direct, semi-direct and indirect effects), on human health (increase of breathing problems and lung cancer for pollution aerosols) and human activities (damage to aircraft engines by volcanic ashes, reduction of visibility by dust or pollution aerosols). In order to monitor and characterize this threat it is necessary to localize, characterize and possibly quantify the presence of aerosols in the atmosphere from the lowest layers (~100 m) up to the tropopause (18 km). We use here an approach based on measurements of the new Raman and dual-polarization LiDAR R-Man510. We present in this paper how it is possible to detect atmospheric layers, to retrieve their optical properties and to classify these layers with this sensor.
Eyjafjallajökull volcano eruptions of ash plumes starting on April 2010 paralyzed completely air traffic in
Europe for several days. During the crisis, Leosphere collected 24/7 real time measurements of the backscatter
profiles, taken by ALS polarizations lidars spread from Denmark to South of France in order to provide quick
looks of the sky at regular intervals for different met agencies and for the Volcanic Ash Advisory Centres
(VAAC) coordinated by UK MetOffice. Moreover, Meteo France supported by other institutions such as CNRS
(Centre National de la Recherche Scientifique), CEA (Commissariat à l'Energie Atomique), CNES (Centre
National d'Études Spatiales) and Leosphere performed several test flights over France and North Atlantic with an
airborne Lidar. These unique data allowed detection and identification of ash plume and provided a guidance
regarding the decision-making chain. The ash mass concentration and its calculation were also discussed.
Urbanized cities in the world are exposed to atmospheric pollution events. To understand the chemical and
physical processes it is necessary to describe correctly the Planetary Boundary Layer (PBL) dynamics and height
evolution. For these proposals, a compact and rugged eye safe UV Lidar, the EZLIDAR™, was developed
together by CEA/LMD and LEOSPHERE (France) to study and investigate structural and optical properties of
clouds and aerosols and PBL time evolution. A new 2D method of PBL detection, developed by Leosphere and
based on image processing, is working on a large set of temporal profiles, typically 6 to 24 hours. It allows the
use of the temporal correlation between the profiles and the integration of atmospheric parameters about PBL
evolution in the detection algorithms. This method, based on the gradient, is using a unique automatic threshold
algorithm that will adapt to any atmospheric conditions. No specific parametrisation is required before
measurements and the final result is more robust than a profile per profile method.
We validated our algorithm during the two campaigns of the ICOS (Integrated Carbon Observation System)
project. These campaigns took place at Trainou (France) on October 2008 and at Mace Head (Ireland) on June
2009 under very different and complicated atmospheric situations, with all different meteorological conditions
(frequent showers, windy situations, no significant inversion layer). Furthermore, this algorithm is able to detect
accurately clouds and rain episode.
Duststorms and sandstorms regularly devastate Northeast Asia and cause considerable damage to transportation system
and public health; further, these events are conceived to be one of the very important indices for estimating the global
warming and desertification. Previously, yellow sand events were considered natural phenomena that originate in deserts
and arid areas. However, the greater scale and frequency of these events in recent years are considered to be the result of
human activities such as overgrazing and over-cultivation. Japan, Korea, Cina and Mongolia are directly concerned to
prevent and control these storms and have been able to some extent to provide forecasts and early warnings. In this
framework, to improve the accuracy of forecasting , a compact and rugged eye safe lidar, the EZ LIDATM, developed
together by Laboratoire des Sciences du Climat et l'Environnement (LSCE) (CEA-CNRS) and LEOSPHERE (France) to
study and investigate structural and optical properties of clouds and aerosols, thanks to the strong know-how of CEA and
CNRS in the field of air quality measurements and cloud observation and analysis, was deployed in Seoul, Korea in
order to detect and study yellow sand events, thanks to its depolarization channel and scan capabilities. The preliminary
results, showed in this paper, of this measurement campaign put in evidence that EZ Lidar, for its capabilities of
operating unattended day and night under each atmospheric condition, is mature to be deployed in a global network to
study long-range transport, crucial in the forecasting model.
To fully understand atmospheric dynamics, climate studies, energy transfer, and weather prediction the wind field is one
of the most important atmospheric state variables. Studies indicate that a global determination of the tropospheric wind
field to an accuracy of 0.5 m/s is critical for improved numerical weather forecasting. LEOSPHERE recently developed
a new generation long range compact, eye safe and transportable wind Lidar, named WLS70, capable to fully determine
locally the wind field in real time in the planetary boundary layer (PBL). First results of the measurement campaign put
in evidence both wind velocity vertical profiles and atmosphere structure derived from Lidar data.
Lidar investigation of temporal and vertical optical atmospheric properties will play a key role in the future for a
continuous monitoring over the whole planet through world ground based networks. The EZ LidarTM, manufactured by
LEOSPHERE, has been validated in several campaigns as that one in Southern Great Plains (ARM) or at Goddard Space
Flight Center (NASA). An EZ LIDARTM with
cross-polarization capabilities was deployed in Kanpur, India in the frame
of TIGER-Z campaign organized by NASA/AERONET in order to measure aerosol microphysical and optical properties
in the Gange basin. In addition, 12 sun-photometers were deployed during this campaign and CALIPSO (The
Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) data were also acquired. In this work we present the results
in retrieving aerosol extinction and backscattering from EZ
LidarTM measurements, and the validation of the space borne
instrument CALIPSO under the satellite track.
EZ LidarTM is also coupled with the photometers to provide the
measurements of the Aerosol Optical Depth over the selected region.
The Laboratory of Science of Climate and Environment (CEA/ CNRS) and LEOSPHERE Company have jointly developed an eye safe, rugged and unattended high resolution scanning lidar ("easy lidar", www.lidar.fr). This system has been used in the frame of the POVA program and has been used in a compact version during the LISAIR (LIdar to Survey the AIR) program in May 2005 in the Paris city, France. The mobile lidar has been used to follow aerosol particles in highways subject to heavy traffic. High spatial and temporal resolution data on the entire planetary boundary layer (1.5 m and 1s respectively) allowed to monitor for aerosol load variability on board a moving car and also to detect for local sources. We observed the doubling of the optical thickness in the morning when traffic is high in the city ring. We also have shown local effect of waste burning plants and train stations. This new type of eye safe lidar will allow to monitor continuously the entire area of a town and suburbs, in order to detect main sources of pollution (transport, traffic jams, industrial plants, natural dust), follow in real time the evolution of the PBL height and provide an estimation of the mass concentration of the aerosol in the PBL.
An airborne coherent Doppler Lidar to retrieve mesoscale wind fields has been developed in the frame of the Franco- German WIND project. The instrument is based on a pulsed CO2 laser transmitter, heterodyne detection and wedge scanner. The performance of the instrument operating on the ground and in the aircraft is reported.