ÓPTICA PURA Y APLICADA – Vol. 37, núm. 3 - 2004
AERONET workshop and Steering Committee Review
May 10-14, 2004
Brent N. Holben (1)
(1) Laboratory for Terrestrial Physics, NASA Goddard Spaceflight Center, Greenbelt, MD USA
PRESENTATION: ABSTRACT:
Workshop Objectives
• Provide an opportunity for the Network participants to collaborate, exchange ideas, understand the AERONET macro objectives and get a better sense of AERONET needs and limitations
• Influence AERONET objectives • Improve field maintenance • Foster new research opportunities • Address issues facing AERONET
AERONET workshop and Steering
Committee Review
May 10-14, 2004
• Welcome
• Logistics:
– Breaks
– Lunch and tourism opportunities
– Transportation to & from Hotel
– Workshop Dinner
– Internet/wireless connectivity
• Introductions
Workshop Objectives
• Provide an opportunity for the Network
participants to collaborate, exchange ideas,
understand the AERONET macro objectives and
get a better sense of AERONET needs and
limitations
• Influence AERONET objectives
• Improve field maintenance
Steering Committee Objectives
• Assess management of AERONET
• Assess AERONET objectives
• Assess Research Directions
• Assess responsiveness to community needs
• Assess funding levels
• Assess growth and expansion issues
• Assess Data Quality
• Assess Data Access
AERONET Overview
• Early Development
– Shifted Funding core study from Diane
Wickland for Tropical RS studies
– Cimel software and hardware development
– Tom Eck &Brent Holben;
– Didier Tanré & Francois Lavenue-PHOTONS
Science Team, 8 to 10 inst.: W. Africa, Cape
Verde ‘94, WMO sanction
AERONET Overview
• Early Development cont.
– Demonstrat: Develop Standard AOD analysis,
windows like browsing
– Nakajima Inversion
– Campaign oriented effort: Brazil 93-95, BOREAS,
SCAR-A, SCAR-C
– Wayne Newcomb-Technical
– MODLAND/LTER 4 inst. In ‘94
AERONET Overview
• Middle Development cont.
– Atmospheric Correction, Brazilian R.S
– SCAR-B: 13 Inst., EOS provided funds
– Strong MODIS support: Land, Ocean and Atmos.
– ‘96 AERONET proposal/Steering Committee
– Alexander Smirnov: Research and QA
AERONET Overview
• Middle Development
– Began calibrating non NASA instruments
– Implemented Federation Concept
– AEROCAN 6 sites
– HQ International agreement requirements
– Additional Staff: GSFC agreements, property and
secretarial
AERONET Overview
• Middle Development
– ‘97 Staff
• Engineer: Nader Abuhassen
• Inversion Specialist: Oleg Dubovik
– Field Campaigns: ZIBBEE, TARFOX, SEAM
– Projects: LBA, IDS-Joel Schafer, Stefan Kinne
– Homepage Development
AERONET Overview
• ‘98 Retrench
– Papers
– Upgrade Computer, Software, Hardware
– Cloud screening methodology applied
– QA data base
– Development of systematic cal and maintenance
schedule-shared spreadsheets
AERONET Overview
• ‘98 retrenching and expansion
– DDF support for follow-on instrument
– Visiting Scientist: Norm O’Neill
• ‘99 Expansion
– Follow-on instrument: Engineer Mikhail
Sorokine
AERONET Overview
• ‘99 Expansion cont.
– Dubovik Code Operational
• Size Dist., SSA, n, m, flux
– Further improvements to Cimel Software
AERONET Overview
• ‘00 Expansion
– Network approaching 100 sites, ~120 inst.
– Roof Calibration facility operational
AERONET Overview
• AERONET Staff:
– Dubovik, Oleg: Research, Algorithm Devlpmt
– Scully, Amy: Secretarial, Shipping, etc
.
– Eck, Tom: Research, Calibration, Inst. Qual
– Holben, Brent: Research, Admin.
– Anho (Don): Technical & Maint
.
AERONET Overview
• AERONET Staff cont.
– Slutsker, Ilya: Programming,Database mgmt
– David Giles: Webmaster, Relational database
– Smirnov, Alexander: Research, QA, Network asmt.
– Sorokine, Mikhail: Engineering, inst. Maint. &
devlpmt.
AERONET Overview
• Adjunct Staff
– O’Neill, Norm: Visiting Scientist
– Schafer, Joel:LBA (research/Calibratin/deploy)
– Cooper, John: Calibration facility
– Carroll, DeVon: HQ Intnl Agreements
– Baldessari, Gina: Branch Financial
AERONET Overview
• Functional Goals:
– Research-~50%
• Underpinning
• Data Analysis
– Operations- ~50%
• Inst. Cal./Characterization
• Field Maintenance
• Administration
AERONET Overview
• Federated globally distributed network
• Public domain data base
– Imposed Std. Calibration
– Imposed Std. Measurements
– Imposed Std. Processing
AERONET Current Status
• Staff: 12 people FTE
• Budget: $1.8 m
• AERONET sites: 120-150 Globally Dist.
AERONET Current Status
• Purchase 4 inst./yr
• Swap-out Pool of ~10 inst.
• Reference instruments: 3 to 4
• Validation
– EOS Core Val. sites (MODLAND): 19
– CERES Val. Sites: 2
– SIMBIOS Val.: 10
Current Status cont.
• Global Coverage (Meteosat, GOES, GMS)
– CGMS & NOAA/NESDIS (Receive site in HI)
– EUMETSAT/PHOTON/WMO
– Plans to include PC download
• Field Campaigns ~2 year
– UAE^2: Dust/industrial
Current Status cont.
• Instruments & Processing:
– Inst. Hardware: Upgrades to 1.6
µ
m encouraged
– Inst. Software: Routinely upgraded
– Processing Software: V. 2 released this year.
• AOD new AOD calculations
• Almucantar & PP QA
– Algorithm Development
• PP: under development
AERONET Current Status cont.
• AERONET Homepage:
http://aeronet.gsfc.nasa.gov
– Downlaod tool: PP, Almuc, AOD, Raw etc
– Multisite Download tool
– Combined data sets: BAMGOMAS
– Almucantar: available under development
– PP under development
Current Status cont.
• Infrastructure
– Well maintained Sphere Calibration Facility
– Dedicated Roof intercalibration facility
– Dedicated Lab
– Adequate Computer facilities
Current Status cont.
• Calibration/Accuracy:
– Sky Radiance: 1-2% ref to NIST 2nd std.
– Sun Vo from MLO Langley:
• AEROSOL: Cv=0.2-0.5%,
– AOD
ref=±0.003
– AOD
field= ±0.01
Current Status cont.
• Research Publications/ Conference etc. since ‘96
– 40 (26) Senior Author
– 82 (45) Junior Author
– ? (12) Enabling
New Activities
• Inversion
– Polarization, PP, Almuc
– AERONET, Model, Sat.
• Processing
– Version 2.0; (Rayleigh, Cloud, pressure, Temp., WV)
– Forcing
• Synergism
– BAMGOMAS
Current Status
• Project Wants:
– Project Deputy (Fired)
– Programming assistant (+)
– ‘Project’ Status (nothing official)
– New instrumentation
• Follow-on (extended wavelengths) (+)
• Lunar/star photometer (-)
AERONET Teething Problems
• Globally Distributed Internationally Federated
Network, ~150 sites
• Quality Assured data since 1993
• Calibrations are known
• Real time cloud screened
• New aerosol products
AERONET Overview Plan
• What is AERONET, the philosophy, and
objectives?
• History and evolution
• Operational Activities
• Research Component
• Management (the glue-why it works)
• Status
AERONET-An Internationally Federated Network
Open data access via website:
http://aeronet.gsfc.nasa.gov/
Real-time & long term column integrated measurements
Research & Enabling Project
Mission Objectives:
AERONET-An Internationally Federated Network
Open data access via website:
http://aeronet.gsfc.nasa.gov/
Real-time & long term column integrated measurements
Research & Enabling Project
Mission Objectives:
AERONET-An Internationally Federated Network
Open data access via website:
http://aeronet.gsfc.nasa.gov/
Real-time & long term column integrated measurements
Research & Enabling Project
Mission Objectives:
AERONET-An Internationally Federated Network
Open data access via website:
http://aeronet.gsfc.nasa.gov/
Real-time & long term column integrated measurements
Research & Enabling Project
Mission Objectives:
AERONET-An Internationally Federated Network
Open data access via website:
http://aeronet.gsfc.nasa.gov/
Real-time & long term column integrated measurements
Research & Enabling Project
Mission Objectives:
Cloud screening and
quality control
Cloud screening and
quality control
Main archive
Level 1.0
Level 2.0
Level 2.0
Level 1.5
Level 1.5
Raw archive
Calibration system
Processing system
Cloud screening
Cloud screening
AERONET web site
GOES (East / West), METEOSAT, GMS GOES (East / West), METEOSAT, GMS
CIMEL sun/sky radiometer CIMEL sun/sky
radiometer Data Collection System
Automatic Processing System
Data Collection System Automatic Processing System
Not an Automatic system!!
Operations
Research
Products
Calibration
Lab maintenance
Shipping
Field deployment
Field Maintenance
Data Checks
QA
International agreements
Develop improved approaches
Requirements for high data quality
Developed new products
Aerosol Characterization
Validation
Field Campaign studies
Synergism w/ other data sets
The rain in Spain stays…
Where the Hell is Oleg? How can a
Bald guy look So fuzzy?
Operational System
• Objectives
• Structure (Get the data, process the data, and make
it available in real time)
– Calibration & Maintenance (spreadsheets)
– Field Maintenance (bi-weekly checks)
– Processing (centralized)
– Archive
– Data Retrieval
Operational Objectives
• Provide an efficient and verifiable system
for delivery aerosol optical properties
– Traceable calibrations
– Rapid turn around of field instruments
– Easy access to the data
Operations: Calibration Issues
• Volume of instruments (2 inst every 3 days)
• Solution: Develop a distributed calibration
network
– Establish Master instruments & Transfer calibration
standard?
– Establish standard integration spheres
– Procedures, schedules and standards
– Centralize thru a single relational database
Operations: Field Maintenance
• Keep the systems operating during the 1 year field
deployment
• Solutions:
– Site Managers: Weekly inst. and web check
– Biweekly checks-staff/site manager followups:
• Video conferencing, email and telephone
• 4 to 6 weeks
Operations: Processing &
Products
• Centralized Processing
– Operational Code based on refereed
algorithms/corrections
• Realtime issue: 2 to 12 hrs after acquisition
• Ver 2 due ~July, insignificant changes to AOD, improve Pw,
Add PP inversions
– New Products
• Cloud Optical depth
• Cirrus Product
• BAMGOMAS
In water radiometry
4.9 4.3 4.2 4.2 4.3 4.6 Quadrature sum 3.1 3.1 3.1 3.1 3.0 3.0 Environ. effects 3.0 1.7 1.6 1.7 2.1 2.5Residual shad. pert.
2.3 2.4 2.4 2.3 2.3 2.4
Abs. calibration [1]
665 555 510 490 443 412
Uncertainties (Lu)
AAOT
[1]Including the calibration source accuracy, Ifaccuracy
and instrument stability
Above water radiometry
CE-318 (sea-viewing)
CE-318 (sky-viewing)
G.Zibordi, F. Mélin, S. B. Hooker, D. D’Alimonte and B. Holben. An autonomous above-water system for the validation of ocean color radiance data. IEEE Transactions in Geoscience and Remote Sensing ,42:401-415, 2004 .
S.B.Hooker, G.Zibordi, D. van der Linde, D.D’Alimonte, J.F.Berthon and J.Brown. Tower perturbation measurements in above-water radiometry. NASA TM 2002-206892, v. 23 S.B.Hooker and E.R.Firestone, Eds., NASA Goddard Space Flight Center, Greenbelt, Maryland, 2003, 35 pp.
12.2 4.1 4.1 4.4 4.7 Quadrature sum 12.0 3.0 3.1 3.7 4.0 Environmental perturbations 0.9 1.8 1.6 1.0 1.0 Viewing angle correction[2]
2.1 2.1
2.1 2.1
2.2 Absolute calibration[1]
670 555
500 440
412
Major uncertainties (Lw)
[1]Including the calibration source accuracy and instrument stability [2]Assuming an arbitrary 25% in the applied correction
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G.Zibordi, F. Mélin, S. B. Hooker, D. D’Alimonte and B. Holben. An autonomous above-water system for the validation of ocean
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G.Zibordi, F. Mélin, S. B. Hooker, D. D’Alimonte and B. Holben. An autonomous above-water system for the validation of ocean color radiance data. IEEE Transactions in Geoscience and Remote Sensing , 42:401-415, 2004 .
A-SRVN - AERONET-based Surface Reflectance
Validation Network
Daily Data Collec
MODIS, MISR
(area ~ 16x16 km
Ancillary Data
AERONET aeroso
WV, NCEP ozon
Automatic AC
(single validated
unified algorithm
Main Function
PRODUCTS
BRDF
1. Point-wise in Observation Angles 2. Best-fit MRPV (MISR)
3. Best-fit Kernel (MODIS)
Albedo
1. Spectral
2. Shortwave Broadband (SB) 3. Spectral and SB Fluxes, PAR
Spectral Regression(for AOT retrieval) 1. 2.1 µm →blue & red
EXPECTED BENEFITS
1. Validation of surface albedo/BRDF 2. Development of global surface
climatology for aerosol retrievals 3. Way to MODIS – MISR data fusion
Calibration Analysis
4. Vicarious calibration
Operations: Archive and
Retrievals
• Centralized Archive
– One source easy to make corrections/additions
– Authorship notification
– Long Term Archive not resolved!
– Breaking up data archive/access confuses user!
• Web-based Retrievals
– By Individual sites, selectable parameters
– Preferred Access point
Operations: Instrument Diversity
– Cimel 318 Standard (340, 380, 440, 500, 675, 870, 940, 1020
nm)
– Cimel 318 Polar (440, 675, 870, 870 polar, 940 1020)
– Cimel 318
New
Standard
– Cimel 318
New
Polar
– Cimel 318 Extended Standard ( + 1640 nm)
– Cimel 318 Extended Polar ( + 1640 nm)
– Cimel 318 SeaPRISM (412, 443, 490, 555, 675, 870, 940,
1020)
– Cimel 318
New
SeaPRISM
– Cimel 318 Standard BRDF
– Cimel 318
New
BRDF
Operations: Instrument Diversity
Solution: UPGRADE All instruments to ‘
New
’
Operations: Data Acquisition
– Vitel GX 1004 (with display): no use fee, data
volume limited
– Vitel 1004 (without display): As above
– Sutron (without display): As above
– Manual PC Download: Human intensive
– Daily Automatic PC download: PC must be within
10 m of site, internet to PC
– RT PC download: PC within 1 km, internet access
– Sat Telephone: $
– Cell phone: $
Operations: Data Acquisition
Operations Issues:
Integration w/ other databases
• BSRN
• EARLINET
• SKYNET
• GAW
• Satellite systems
Operations-Filters
• Filter Stability: variable depending on batch and
wavelength-sometimes!
• BARR associates: best reputation
• Costs doubled in 2001; ~ $140 ea
• Initially Replaced all Spectragon filters/BARR
Research
• Objectives
• Aerosol Characterization
• Climatology
• Aerosol Dynamics
• Aerosol Radiative Forcing
• Validation
Research Objectives
• Provide scientific quality assessment to the
calibration process
• Provide scientific under pinning for data
processing and development
• Initiate and participate in field campaigns
• Characterize aerosol optical properties
• Develop aerosol climatology
0.00 0.20 0.40 0.60 0.80
JAN MAR MAY JUL SEP NOV
aerosol optical depth (500 nm)
1993-2003
