AERONET Quarterly, March 2000

Welcome everyone to the AERONET Quarterly. This edition will address the following topics:

Launch of Terra

Research/Publications

Operations

AERONET Partnership-Photon

Acknowledgements

Calibration/Accuracy

Deployments

New e-mail addresses

Launch:

Terra was launched on December 18, 1999. The satellite was inserted into the Landsat world reference orbit and will follow about 15 minutes behind Landsat -7. Later this year NASA's EO-1 and Argentina's SAC-C will be launched in the same orbit. Terra's doors opened on Feb. 25th and the first images of MODIS, MISR, ASTR and MOPPIT have been acquired. The MODIS 250 m resolution images are nothing less than spectacular and the aerosol algorithms are now churning out aerosol optical properties over the globe. The AERONET data, your data, are a critical element for validation of those retrievals, development of improved algorithms and aerosol models. AERONET, now approaching 100 field sites, is an outstanding achievement that has relied on scientific goodwill and collaboration of AERONET staff, PIs, site managers, program managers and various institutions around the world. I expect that we'll see some very innovative and important ways to use our collective data-base in the near future, not just for Terra but Landsat, TOMS, SeaWiFS, AVHRR, POLDER, the geostationary birds, EO-1, GLI, PICASSO, AQUA, TRMM, GLAS, PARASOL, and many others to come. Thanks everyone.

Research/Publications:

The aerosol optical depth and angstrom exponent are the well known parameters of the network observations. The particle volume distribution, single scattering albedo, modal size parameters, asymmetry factor, and complex index of refraction from Oleg Dubovik's inversion are proving to be physical, reliable, verifiable and more interesting as analysis proceeds. Research on these data is moving forward rapidly inside and outside the project. Dubovik's sensitivity paper is in press and a paper on theory is under review. Sasha Smirnov's paper on cloud clearing and quality assuring the AOT data has been accepted by RSE. Tom Eck published a paper in JGR on the wavelength dependence of the AOD resulting in a new product, a’. The AOD climatology paper is still in preparation and should be submitted by April. All papers are available on the AERONET homepage. Other papers pertaining to field campaigns, analysis of particular events, or analysis of AERONET data subsets are ongoing inside and outside the project.

Operations:

The roof modification is not fully completed however we transferred our operation entirely to the new platform in mid December. We can accommodate ~25 simultaneously operating instruments for intercomparisons. Additionally we have reserved a row of tables for flux sensors, MFRSR and the PREDE sun sky radiometer. Our efficiency has greatly improved with this facility (photos on AERONET Homepage). I would estimate 2 to 3 weeks turnaround for field instruments assuming reasonable weather, no repairs or major maintenance is required.

New software for the cimel has virtually eliminated the concern of binding cables during almucantars. All instruments returned for calibration will have their software upgraded.

The AERONET homepage has a new look and as time permits new capabilities will be added. The current effort has greatly improved operational issues, with on-line manuals, weekly instrument checklist, instrument set-up photos, UT clock, interactive cimel and vitel display and troubleshooting diagnostic manual and plenty of photos to help site managers. Scientific descriptions of parameters, links to PHOTON, AEROCAN and as available AERONET PIs are being added. Thanks especially to Joel Schafer for this. Three data bases are available through the homepage: Level 1 unscreened, level 1 cloud screened (level 1 includes realtime and post field calibrated as available) and level 2 Quality Assured data (incorporates pre and post field calibration and must meet the QA criteria, Smirnov paper). Access to all data products through the homepage will be graphically based.

Who wants to become a mil an AERONET PI? This information and the equipment supported by the network are included on the homepage.

Acknowledgments:

AERONET is a federated program with core funding from NASA to support calibration processing and data archive as well as many field sites and core research. Each university, institute and individual contributes to the growth of the program. PHOTON, a co-founder of AERONET, supported by CNES and CNRS, is closely coordinated with the NASA activities and provides similar support for the polarization instruments in Europe and West Africa. All calibrations, processing and archiving currently performed at GSFC are backed up by PHOTON LOA in Lille, France. Data access is also available from Lille. See the AERONET Homepage for more details and links. It is important to recognize the independent activities of PHOTON and the support of CNES and CNRS for PHOTON within the overall AERONET activities.

As the network expands and users access multiple sites for ensemble analysis, it becomes quite easy to accidentally forget to notify all the PIs involved although we've done very well so far. The MODIS Atmospheres team has asked AERONET to provide a daily updated spreadsheet of aerosol optical properties for all sites for the MODIS overflight time such that the aerosol properties can be directly compared for all sites. Thus validation is made possible relatively quickly by taking advantage of the diversity of aerosols represented in our network. This falls within the mandate for AERONET and the spirit of the public domain data-base but bypasses our ‘collaboration announcement’. We must insure that everyone is credited for his or her work. My solution is to make this a public domain AERONET multisite product available through the AERONET homepage for each satellite system. All sites will be used unless a PI contacts me with his objection. An additional ‘collaboration button’ will be added requiring acknowledgement of each PI whose data contribute to the study. Thus for analysis and publications developed from individual downloads, authorship must be offered but for downloads of multisite products, only acknowledgement is required. Please let me know your thoughts and concerns regarding this proposal. In order to avoid potential misunderstandings, all future requests for global products should be addressed to the AERONET project leader for discussion.

Calibration/Accuracy:

The calibration process is described in detail in the homepage but involves a series of pre and post field intercomparisons between the field and reference instruments for direct sun data and field instruments with the reference integrating sphere. A weekly updated calibration spreadsheet will appear on the homepage thus allowing instrument owners to track the characterization and calibration progress of their instrument. The sphere is calibrated monthly and a link is on the AERONET homepage which tracks it's calibration.

Three MLO reference instruments are used. The Vo coefficient of variation of daily Vo values at MLO for the aerosol filters was ~0.10-0.50% based on 5 to 15 individual morning Langley Plots for each instrument. The water vapor 940 channel coefficient of variation typically ranges from ~2.1-4.5% . The zero airmass voltages for all channels have been relatively stable (<0.3%/Mo., part of which may be random variability ) over the last 3 months except one 1020 nm filter which degraded at a rate of ~0.8% per month >from November 99 through January 2000. Degradation of some other 1020 nm filters in non-reference field instruments has also been noted over the last ~6-8 months. Pre and post field calibration largely removes this bias for a typical in field accuracy of ± 0.015 in AOD. Suspect filters will be replaced during the routine postfield calibration/maintenance process.

New Partners and sites:

There are approximately 110 instruments in the network with about 80 active field site. The following table shows the new sites installed in the past three months and new sites expected through this year. The homepage lists all sites.

New Sites 11/99 -3/00

Host PI

Institute

Location

Ownership

Installation Date

Jeannette van den Bosch

NASA Dryden Dryden

JVDB

1/00

Andrew Lacis

NASA GISS

NYC

AERONET

3/00

Hector del Valle

CONAE

Patagonia

SIMBIOSIS

3/00

Antonio

Inhaca, Mozambique Met/Mozambique

AERONET

3/00

Dave Meyer

ErosDData Center

EDC

Meyer

3/00

Dave Meyer

ErosDData Center

Konza Prarie

Meyer

3/00

Jeff Jenner

NASA Stennis

Stennis Mississippi

Jenner

2/00

Robert Frouin

Scripps

LaJolia, CA

Frouin

3/00

Sergio PUGNAGHI

Università di Modena

Lampedusa, Italy

Sergio PUGNAGHI

4/00

Ross Mitchel

CSIRO

Lake Argyle, Austr

Ross Mitchel

12/99

Dennis Clark

NOAA

Ohau, HI

SIMBIOS

3/00

Susan Moran

USDA

Maricopa, AZ

AERONET

3/00

New Sites and Redeployments 4/00-12/00

Host PI or

Site Manager

Institute

Location

Ownership

Installation Date

Andi Andrea

Max Planck Inst.

Mainz, Germany

MP

??

TBD

Univ. of Botswana

Maun, Botswana

AERONET

5/00

Wilferd Versfeld

Etosha Natl Park

ENP, Namibia

AERONET

5/00

Peter Kipp

?

Helgoland, Is., Ger

??

??

Hu Xiuqing

Sat Met Institute

3 val sites

Sat Met Institute

??

Soo Chin Liew

Natl Univ. Singapore

Singapore

Natl Univ. Singapore

??

??

Krasniorsk, Russia

NASA/Murphy

5/00

Sophie Moreau

Bolivian Met Service

Altiplano, Bolivia

AERONET

6/00

Paul Hobson

University of Wales Swansea,

Barton Bendish, UK

AERONET

6/00

Phyllis Adams

Univ of Alaska

Bonanza Creek, AK

LTER

3/00

Fred Bierlamier

USDA/Univ of O

HJA

LTER

3/00

Ray Johnson

Thompson Zoo

Thompson, Manitoba

AERONET

4/00

TBD

Prince Albert,

Waskisu, SASK

AERONET

4/00

Peter Scott

NGO

Churchill, Ontario

AEROCAN

4/00

TBD

Univ. Arizona

Railroad Valley, NV

AERONET

5/00

Merv Lynch

Curtin Univ

Perth, Australia

SIMBIOS

5/00

TBD

?

Katibougou, Mali

PHOTON

4/00

TBD

?

Dakar, Senegal

PHOTON

5/00

TBD

?

Paris, France

PHOTON

6/00

TBD

?

Hamburg, Germany

PHOTON

5/00

TBD

?

Crete, Greece

PHOTON

10/00

TBD

?

Egypt

PHOTON

00

TBD

?

Tunis, Tunisia

PHOTON

00

 

The AERONET Steering Committee will be convened at NASA's GSFC on April 18 and 19 to review the program. A summary will be reported in the next AERONET Quarterly.

Change of e-mail address for the AERONET team. Please replace spamer with aeronet for all team members e-mail addresses. The new addresses are:

brent@aeronet.gsfc.nasa.gov

naji@aeronet.gsfc.nasa.gov

tom@aeronet.gsfc.nasa.gov

ilya@aeronet.gsfc.nasa.gov

asmirnov@aeronet.gsfc.nasa.gov

nader@aeronet.gsfc.nasa.gov

norm@aeronet.gsfc.nasa.gov

wayne@aeronet.gsfc.nasa.gov

lapyonok@aeronet.gsfc.nasa.gov

anne@aeronet.gsfc.nasa.gov

joel@aeronet.gsfc.nasa.gov

dubovik@aeronet.gsfc.nasa.gov

msorokin@spamer.gsfc.nasa.gov

 

If you wish to add someone or be deleted from this mailing please reply to least@pop900.gsfc.nasa.gov.

Cheers,

Brent