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LidarDIAL system
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Summit of Mount Etna. Plume. 10 km. Laser beam. Lausanne, 12/11/09. 12. Lidar ... From Etna to Stromboli... The lidar is directed to the plume with a coelostat ... – PowerPoint PPT presentation
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Title: LidarDIAL system
1
Lidar/DIAL system
Italian National Agency for New Technologies,
Energy and Sustainable Economic Development
- Luca Fiorani, Francesco Colao, Antonio Palucci
- Laser Applications Section, ENEA, Italy
- 0th BONAS meeting
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Atmospheric lidar
- Lidar (light detection and ranging) laser radar
- A laser sends a light pulse to the atmosphere
- The atmosphere interacts with the laser beam
- A telescope detects the backscattered light
- Rct/2
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Advantages of lidar
- Continuous retrieval of aerosol load, wind speed
and gas concentration profile in a considerable
range and with a good spatio-temporal resolution - Probe-less measurement, thus eliminating the
possibility of modifying the sample - Integrated-path determination, less sensitive to
local effects - Capability of sweeping the complete hemisphere,
thus allowing to follow the physico-chemical
dynamics of the atmosphere
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Backscattering lidar
- Lidar equation
- n(R,?)n0(?) (A/R2) ?(?) ?(R,?) (c?D/2)
exp-20?R?(R,?)dR - n (n0) number of detected photons (transmitted)
- Rct/2 is the range (c is the speed of light, t
is the time between transmission and detection) - ? is the wavelength
- A (?) is the detection surface (efficiency)
- ? (?) is the backscattering (extinction)
coefficient - ?D is the response time of the detector
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Differential absorption lidar
- DIAL (differential absorption lidar) equation
- C(R)1/2(?ON-?OFF)(d/dR)lnn(R,?OFF)/n(R,?ON)
- ?ON (?OFF) is the cross section of the molecule
at ?ON (?OFF) - ?ON (?OFF) is the more (less) absorbed
wavelength
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Lidar at Frascati
- From the fixed lab to the mobile lab
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Monitoring application
- Power Plant of Cerano (Brindisi)
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Monitoring application
- Concentration profiles in industrial zones
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Monitoring application
- Spatiotemporal evolution
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Plume profiling
- Experimental scheme
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Plume profiling
- Geographical situation
Laser beam
Summit of Mount Etna
Plume
Lidar
10 km
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Plume profiling
- SantAlfio (Catania) Santuario Magazzeni
Optics Letters 34, 800 (2009)
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Plume profiling
- Extinction coefficient calculated at 10.6 µm with
an algorithm similar to those by JD Klett,
Applied Optics 20 (1981) 211 and FG Fernald,
Applied Optics 23 (1984) 652
Maximum range gt 5 km
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Plume profiling
- Spatiotemporal evolution
Spatial resolution 15 m, Temporal resolution 1
min
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From Etna to Stromboli
Stromboli
Etna
Stromboli
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From Etna to Stromboli
- The lidar is directed to the plume with a
coelostat
12-17 September 2009
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From Etna to Stromboli
- Lidar signals
Noise
Plume
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From Etna to Stromboli
- Water vapor concentration (preliminary)
Meteo Station
Plume
19
BONAS
- Explosive compound or precursor vapors-
Acetone- TATP- HCl-
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FORTUNAS!
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