ftir campaigns at ile de la réunion corinne vigouroux, martine de mazière, a.c. vandaele, e....
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FTIR campaigns at Ile de la Réunion
Corinne Vigouroux, Martine De Mazière, A.C. Vandaele, E. Neefs, F. Scolas, T. Egerickx, C. Hermans, K. Janssens Belgian Institute of Space Aeronomy, Brussels, Belgium
B. Barret, P.F. Coheur, S. Fally, M. Carleer, R. ColinUniversité Libre de Bruxelles, Brussels, Belgium
and
J. LeveauUniversité de La Réunion, St Denis, Ile de La Réunion / France
Measurement site locations
Site 1:Université de La RéunionAltitude: 50 m20°54’ S – 55°29’ E
Site 2:Piton du MaïdoAltitude: 2203 m21°04’ S – 55°23’ E
Scientific :
– Initiate long-term monitoring of the atmospheric composition at a (sub)tropical site by FTIR remote-sensing, in the frame of NDSC.
– Validation of satellite experiments, in particular ACE/SciSAT1.
Technological :
– test BARCOS (Bruker Automation and Remote COntrol System, Neefs et al., 2003) at Maïdo.
Campaigns Objectives
Purpose :
• Measurements in an automatic mode – including remote control options :
Run several days without human assistance, at any time and any geographical location.
Working principle :
• Each day: finds, loads and executes a script for that day.
• Script : list of commands wearing a tag (time or zenith angle) to indicate when the command has to be executed.
BARCOS
BARCOS includes :
• An elementary scripting language
• Solar tracker
• Meteorological station to condition the observations (rain detector, sensors for wind, ambient pressure and direct solar irradiance)
• A data logger and a GPS receiver
• Software (in Labview) for housekeeping, suntracker commanding and interaction with the FTS software (OPUS)
Parallel manual and remote/automatic control are possible
BARCOS solar tracker :
• Can be :
- Bruker solar tracker (BST) - Denver solar tracker(DST) (collaboration with T. Stephen and T. Hawat of Denver Univ.)
• Operating options for DST : - tracking mode : on CCD image of target = sun, moon, star,... - calculated mode - automatic mode
• DST : Image allows cloud detection
Under development
• Automatic Liquid N2 filling• Wireless access to internet for remote control and data
exchange
• Exploitation of meteo data to condition the choice of used spectra:
Time h,min,sec
Time measurement of a spectrum: a few minutes
Maïdo (2203 m)
University (50 m)
MOPD = 125 125 101/175.5 125/250 82/125/250
Strong absorption of WaterVapor near the sea level
Spectral regions (NDSC filters)
• Near- and mid-IR, covering 600- 4400 cm-1.
• Best spectral resolution = 3.5 10-3 cm-1 (MOPD=250 cm)
• Large number of stratospheric and tropospheric gases :
– HCl, HF, HNO3,…
– O3, CH4, N2O, CFC-11, HCFC-22, CO, HCN, OCS, C2H6,...
• Spectra are retrieved by SFIT2 program :
Vertical total column abundances.
Low vertical resolution profiles:
- Based on dependence of absorption line shape on pressure
- Using Optimal Estimation Method (Rodgers).
Retrievals
Sensitivity and Vertical Resolution :
• Are given by Averaging Kernels = rows of A matrix
apriorixtruexA
apriorix
retrievedx
Trace of A: Degrees Of Freedom (if =1 : only total column) Ex: CO ~ 2
Amplitude of A: sensitivity CO: ~ 5 km, 9 km, ~ 5 km, 9 km, no sensitivity above 20 km.no sensitivity above 20 km.
Width of A: vertical resolution
Molecule : O3 : DOF ~ 5HNO3 : DOF ~ 1 (only total column!)
Solar zenithal angle :
ex : DOF of N2O at Maïdo
SNR, … + other retrievals parameters to be optimized
Sensitivity and Vertical resolution depend on:
• Profile retrievals are being optimized (O3, N2O, CO, HNO3,…)
- But… one month : not enough for geophysical conclusions!
• Ground-Based validation of satellite:
- Only FTIR provide correlative data for N2O, HNO3, CH4 profiles.
- Intercomparisons with MIPAS and Odin data are being performed.
Scientific Results of our first campain Sept. 28 - Oct. 29, 2002
Example of Odin Validation : O3
FTIROdinA priori
Odin SmoothedWith FTIR Aver. Kern.
• A priori far from real profile – still both retrievels agree well
• Total column (FTIR-Odin)/Odin = 5.6%
MIPAS
FTIR
Example of MIPAS Validation : HNO3
• A priori far from real profile – still both retrievels agree well
Future in La Réunion island
• 2nd campaign planned for Aug-Nov. 2004, at St Denis, for validation of ACE (overpasses in August and October)
• 3rd campaign planned in the frame of a major tropical campaign in the frame of the EC project SCOUT-O3, in 2005-2006
• Long-time monitoring needed for geophysical work :
waits for NDSC infrastructure at Reunion Island By when ?
Our Role in STAR
Support FTIR pilot study in Paramaribo :
Technical :- Supporting installation and operation of
UBremen FTS - Implementation of BARCOS ?
Scientific :- Contribution to data retrieval and
interpretation
Time Zenith Angle Destination Command Parameter 1 Parameter 2 Parameter 3N99.99 -80.00 OPU RUN_MACRO C:\OPUS\MACRO\AGC_BRUKER.MTX HCL_LOW 1N99.99 -78,00 OPU RUN_MACRO C:\OPUS\MACRO\AGC_BRUKER.MTX MCT_LOW 1N99.99 -76,00 OPU RUN_MACRO C:\OPUS\MACRO\AGC_BRUKER.MTX NO_LOW 1N99.99 -74,00 OPU RUN_MACRO C:\OPUS\MACRO\AGC_BRUKER.MTX HCN_LOW 1N99.99 -71,50 OPU RUN_MACRO C:\OPUS\MACRO\AGC_BRUKER.MTX HCL_LOW 1N99.99 -78,00 OPU RUN_MACRO C:\OPUS\MACRO\AGC_BRUKER.MTX MCT_LOW 1N99.99 -76,00 OPU RUN_MACRO C:\OPUS\MACRO\AGC_BRUKER.MTX NO_LOW 1N99.99 -74,00 OPU RUN_MACRO C:\OPUS\MACRO\AGC_BRUKER.MTX HCN_LOW 1
Time Zenith Angle Destination Command Parameter 1 Parameter 2 Parameter 3N99.99 N99.99 SCR POWERONN99.99 N99.99 HSK SCAN99.99 N99.99 SCR STARTSESSIONN99.99 N99.99 HSK SCAN99.99 N99.99 SCR BEFORENOONN99.99 N99.99 HSK SCAN99.99 N99.99 SCR AFTERNOONN99.99 N99.99 HSK SCAN99.99 N99.99 SCR STOPSESSIONN99.99 N99.99 HSK SCAN99.99 N99.99 SCR POWEROFFN99.99 N99.99 HSK SCA
Example of Odin Validation : O3
OdinFTIRA priori
Odin SmoothedWith FTIR Aver. Kern.
• A priori far from real profile – still both retrievels agree well
• Total column (FTIR-Odin)/Odin = 3.3 %
Example of Odin Validation : O3
• A priori far from real profile – still both retrievels agree well
• Total column (FTIR-Odin)/Odin = 9.9 %
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