yuri arshinov and sergei bobrovnikov ioa –tomsk - russia

WMO TECO 4-6 December 2006

ÉCOLE POLYTECHNIQUE FÉDÉRALE DE LAUSANNE

Logo optimisé par J.-D.Bonjour, SI-DGR

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NewNew optical remote sensing instruments for optical remote sensing instruments for water vapour monitoring developed at the water vapour monitoring developed at the

Swiss Federal Institute of Technology Swiss Federal Institute of Technology Lausanne - EPFLLausanne - EPFL

Valentin Simeonov*, Todor Dinoev, Pablo Ristori, Marian Taslakov, Mark Parlange, Ilya Serikov and Hubert van den Bergh

Swiss Federal Institute of Technology –Lausanne Switzerland

Yuri Arshinov and Sergei BobrovnikovIOA –Tomsk - Russia

Bertrand CalpiniMeteoSiss - Payerne




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OutlineOutline

•Lidar principle

•Automated water vapor Raman lidar for operational use at MeteoSwiss

•High spatial and temporal resolution water vapor /temperature Raman lidar

•Mid IR, long open-path system for trace gas, water vapor and temperature monitoring




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LidarLidar principleprinciple

)()(

)()(

2

2 RRS

RSnRw

N

OH

R

R

NO

N drrS

SR

0

2

2

2 )(exp)(

)(

PP(R)

R

P

0

)()()(2

RTRR

APkRS

R

A

Raman method for water vapormeasurements

FOV

S(R)




13.4.93Water vapor Raman lidar for Water vapor Raman lidar for operational use in meteorologyoperational use in meteorology

Requirements Fully automated, continuous operation Long term stability High reliability > 85% technical availability Eye safety

Lidar specificationsWater vapor mixing ratio AerosolDetection limit 0.01 g/kg Extinction & 355 nm

Backscatter & 355 nm Statistical error < 10 %

Height range / resolution Daytime 150-5’000 m / 30-400 m Night time 150 – 10’000 m / 30-600 m Acquisition time 15-30 min




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GeneralGeneral lidarlidar designdesign

To the polychromator

TransmitterNd:YAG laser400 mJ & 355 nm30 Hz rep. rateBeam expander 15 X




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EyeEye safetysafety

0 1 2 3 4 5 6 7 8 9 10

0

100

200

300

400

Ver

tica

l H

eigt

h, m

Time of Exposure, s

Nominal Hazard Distance

Danger zone

EYE and SKIN safe zone

0 1 2 3 4 5 6 7 8 9 10

0

100

200

300

400

Ver

tica

l H

eigt

h, m

Time of Exposure, s

Nominal Hazard Distance

Danger zone

EYE and SKIN safe zone

Laser energy 400 mJ @ 355 nm, beam diameter 140 mm (after expansion)




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General lidar designGeneral lidar design

To the polychromator

Receiver (NFOW/NB)Narrow Field of ViewNarrow bandMatrix telescope of four Ø 30 cm mirrors 0.2 mrad FOV




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Spectral isolation and detectionSpectral isolation and detection

Diffraction grating polychromatorDiffraction grating polychromator• Long term stabilityLong term stability• Narrow band detection – 0.3 nm pass-band (possible adjustment)Narrow band detection – 0.3 nm pass-band (possible adjustment)• Oxygen channel – aerosol correctionOxygen channel – aerosol correction• 10101212 suppression of the laser line suppression of the laser line• 40% efficiency40% efficiency




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Diffraction grating

Fiber holder &collimating lens

Parabolic mirror

Doublet lens

Photomultipliers

Polychromator viewPolychromator view




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Lidar cabinLidar cabin

6 m 2.4 m

2.4 m




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Outside viewOutside view




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Inside viewInside view

Laser

Telescope

Polychromator

Fibers

Fibers Output of the

Beam Expander

Mirrors

Telescope




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•Raw data correctionRaw data correction•HH22O retrieval with a O retrieval with a

predefined error (space predefined error (space resolution variable)resolution variable)•Data storageData storage

Input parameters • Averaging time• Accuracy• Vertical resolution limits• Calibration coefficient

DataData treatmenttreatment modulemodule




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DataData treatmenttreatment modulemodule




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Last dataLast data




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FutureFuture stepssteps

Experimental operation in Lausanne till May 2007 Calibration - with tethered balloon (Snow White) - with GPS data - absolute calibration tests Reliability testsVerification with balloon measurements in PayerneStart of operation at MeteoSwiss -July 2008




13.4.93High spatial and temporal resolution High spatial and temporal resolution Raman lidar for water vapor and Raman lidar for water vapor and

temperature measurementstemperature measurements

Lidar specifications

Fixed spatial resolution of 1.5 m Temporal resolution 1 sOperational range 10-500 mWater vapor and temperature statistical error < 10 %Scanning capability

Goal: Study of turbulent boundary layer intercomparison with LES model




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264 266 268 270 272 274 276 278 280 282 284 286 288 290 292 294 296 298 3000

1

2

3

4

5

6

7x 10

-30

Wavelength [nm]

Inte

nsi

ty [a

.u.]

---- Pure Rotational Raman N2 & O

2

---- O2 Ro-vibrational Raman

---- N2 Ro-vibrational Raman

---- H2O Ro-vibrational Raman

Edge Filter Transmission

---- Elastic Line

BFF

AT

1

2ln




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LidarLidar setupsetup

Acquisition System

M1

Water vapor Polychromator

M

EF F

Nd:YAG 40 mJ @ 266 nm

100 Hz

Temperature Polychromator

BE

EF

M2

Ø 0.3 m

Ø 0.2 m Ø 0.2 m

Ø 0.1 m




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PolychromatorsPolychromators designdesign

Stage I

Stage II

GR

GR

L

L

F

to PMTs

from telescope




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LidarLidar viewview

Water vapor polychromator

Temperature Temperature polychromatorpolychromator

TelescopeTelescope

LaserLaser

Acquisition Acquisition systemsystem




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TestTest resultsresults




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VerticalVertical time-seriestime-series




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Open-path midOpen-path mid IRIR techniquetechnique

•Most polyatomic molecules have specific mid IR spectroscopic features (GHG)•High sensitivity•Haze immunity•Virtually immune to interference by other species•Concentration measurements are averaged over an extended path, i.e. much less affected by local unrepresentative fluctuations in gas concentration than point sensors data is better suited for numerical models•Measurements can be made in regions of difficult access, especially above ground level •No material contact between gas and sensor i.e. no degradation of the gas being measured or "poisoning" of the sensor




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MidMid IRIR open-pathopen-path principleprinciple

Intrapulse tuning:

LN

)ln(




13.4.93Species and atmospheric Species and atmospheric parameters measurable within a parameters measurable within a

singlesingle wavelength scanwavelength scan

H O2

CO2H O2

O3 O3

Temperatureand

humidity

NH3, CH4 , N2O and ethanol alsodetected in lab conditions




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Comparison between QCL and standard ozone

analyzers measurements at 220 m path-length.

0 10 20 30 40 50 60 700

10

20

30

40

50

60

70 Concentration calculated from the experimental differential transmittance

Theoretical line

Ozo

ne

co

nc

en

tra

tio

n (

QC

L)

[pp

b]

Ozone concentration (Ozone analyzer) [ppb]

OzoneOzone detectiondetection




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TemperatureTemperature measurementsmeasurements usingusing midmid IRIR lineslines ofof H2OH2O

285 290 295

1.1

1.2

1.3

1.4

1.5

1.6

1.7

Ra

tio

Temperature [K]

Ratio

2

1

ln

ln

T




13.4.93Space-resolvedSpace-resolved open-pathopen-path measurementsmeasurements

Transmitterreceiver

RetroreflectorsBeam path




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ConclusionConclusion

Automated water vapor lidar for meteorological applications was developed. Experimental operation ongoing, final installation in Payerne foreseen for mid 2008

Water vapor and temperature Raman lidar with high spatial and temporal resolution was built

First non cryogenic mid IR system for open path monitoring of trace gases water vapor and temperature has been developed.

Planned tests for GHG detection, humidity and T° intercomparison with conventional techniques




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Thank you

yuri arshinov and sergei bobrovnikov ioa –tomsk - russia

Documents

nm statistical error

temperature statistical

mingeneral lidar designto

water vapour monitoring

nm backscatter

acquisition time

night time

operational use