Multi-plateform monitoring of aerosols, clouds and atmospheric

Multi-plateform monitoring of aerosols, clouds and atmospheric

Multi-plateform monitoring of aerosols, clouds and atmospheric
boundary layer dynamics in Vosges supersite in the framework of
the COPS field campaign
Juan Cuesta1*, Dimitri Edouart1* ,Laetitia Estevan1, Cyrille Flamant2, Pierre H. Flamant1
1Institut Pierre-Simon Laplace/Laboratoire de Météorologie Dynamique
2Institut Pierre-Simon Laplace/Service d'Aéronomie
* Contact: cuesta@lmd.polytechnique.fr , edouart@lmd.polytechnique.fr
Summary and objectives
VOSGES SUPER SITE (SS): at Meistratzheim (48.4°N 7.5°E 161m)
Atmospheric aerosols play an active role in cloud hydrological
cycle, and thus precipitation processes, as they act as cloud
condensation nuclei and ice nuclei. Their hygroscopic properties
and number concentration have an impact in cloud microphysics,
leading to suppress or enhance precipitations. The
Transportable Remote Sensing Station “TReSS” was deployed in
Vosges supersite in July 2007 in order to monitor the different
contributions of atmospheric aerosols in the Rhin Valley region
(i.e. rural and urban aerosols, desert dust in the upper
atmospheric layers), clouds and atmospheric boundary layer
dynamics. In the framework of COPS, TReSS deployment aimed
at studying the role of aerosols on cloud properties. TReSS
dataset has been conceived for :
1) Assessment of aerosol mixture impact on optical and
hygroscopic properties,
2) Cloud cover description and optical properties retrieval,
3) CALIPSO satellite data validation and
4) Aerosol /cloud numerical modelling validation.
1.IGN RAMAN Lidar
• 355 nm
• N2 Raman
• H2O Raman
2. Ceilometer
• ~800 nm
1. Radiosoundings
3. Meteorological
sensors
4M Météo France
4. Fluxes
• Anemometer
• H20
• CO2
5. UHF doppler Radar
GPS
1. Mini-Lidar
• 532 nm // and depolarization
• 1064 nm
• Raman 607 nm
4. Aerosols
Chemistry
5. CLIMAT:
4 channel
IR radiometer
2. Sun photometer
TReSS “Transportable Remote Sensing Station”
Active and passive remote sensing of aerosols and clouds
3. Optical particle counter
5. Narrow band IR radiometer
6. Webcams
In-situ sensors (microphysics + hygroscopic properties) at
the surface
Description of the TReSS platform
Attenuated
TReSS is an autonomous and high-performance system designed to observe
radiative and structural properties of clouds and aerosol layers, as well as
atmospheric boundary layer (ABL) dynamics. The standard payload is made
of the following instruments: 1) a multi-wavelength elastic and Raman
channels backscatter Mini-Lidar operating at 532, 1064 and 607 nm (with
diverse polarization capability at 532 nm), 2) a sun-photometer, 3) an
optical particle counter 4) filters for subsequent aerosol composition and
hygroscopic properties analysis, (5) two multi-channel infrared radiometers
including the CLIMAT radiometer from the Laboratoire d’Optique
Atmosphèrique from Lille and (6) a full sky visible web-type camera.
ACTIVE
● Backscatter
coefficient
● AOD &
Angstrom coefficient
● Depolarization
ratio
● Albedo,
Asymmetry factor
Refractive index
● Vertical
resolution
~15 m
● A profile
every 10 s
backscatter
PASSIVE
(Integrated over the
depth of
the atmosphere)
Mini-LIDAR
Sunphotometer
Structure of
Aerosol and cloud
layers
Depolarization
ratio
Particle shape
Apparent
Angstrom
Coefficient
Particle size
Variables measured by TReSS
• Atmospheric aerosols: backscatter / extinction coefficient profiles (15 m vertical resolution, 10 s temporal resolution); Aerosol layers optical and geometrical depths; column-integrated size distributions and
refractive indexes, surface measurements of size distribution between 0.15 and 10 µm (1 minutes) and chemical composition (Black carbon, Organic carbon, Hydrosoluble carbon, Ions, Mass, every 12 hours)
• Clouds: backscatter / extinction coefficient profiles; cover full-sky visible images (10 s); Thick cloud base altitude; Thin cloud optical and geometrical depths (15 m resolution);
• ABL diurnal cycle (using aerosols as tracer) and Integrated water vapor content; IR irradiance in the 8-13µm, 11.5-12.5 µm, 10.5-11.5 µm, 8.2-9.2 µm and 9.5-11.5 µm ranges;
Prevailing meteorological conditions in July 2007 observed in Vosges SS
Expected conditions: only 4 cases of typical diurnal PBL cycles (30/07)
Attenuated backscatter βapp
Low and mid level clouds: 20 cases. 11/07 example
Free
troposphere
Rain
Low level clouds (ABL top)
ABL (heterogeneous structure)
High level clouds (cirrus): 10 cases. 22/07 example
(Surface heating => Dry convection => Cloud formation)
Front approaching depicted by
Cirrus clouds
Low level clouds (top ABL, with mixed layer development)
PBL diurnal cycle
Aerosol variability
Dust transport episodes
Aerosol concentration at the surface
Fog
Rain
NAAPS simulation
(http://www.nrlmry.navy.mil/aerosol/)
15 July episode
Factor ~4
Rain
Desert dust
r (µm)
Total column aerosol optical depth
AOD
1 August episode
Front
Saharan dust episode
Desert dust
Rain
23 July episode
> Coarse particles
Dry layer
(see P. Bosser’s
presentation)
Perspectives and future collaborations
* Golden days: 15/07 and 01/08 (major dust episodes) and 17/07 and 23/07 (interactions)
*Database to study:
* Evolution of aerosol transports: their origin (desert, urban, rural), concentration and size variability
* Variability of aerosol content: e.g. rain scavenging (link with numerical modelling in collaboration S. Berthet, J-P. Pinty from LA)
* ABL evolution influenced by its diurnal cycle, orography?, wind shear? (Collaboration with S. Batin SA/IPSL)
* Hygroscopic properties of aerosols using chemical analysis ( collaboration with Jean Sciare LSCE /IPSL)
* Synergy with other measurements: IGN (P. Bosser and O. Bock), 4M-Meteo France (G. Pigeon), LEANDRE 2 (C. Flamant SA/IPSL)