Folks, Welcome to the AERONET Quarterly.  This is a rather informal note sent more or less quarterly to those involved in the AERONET program.  This and past issues maybe found on the AERONET website (Link to “papers and presentations).  This issue is largely geared to the PIs and site managers.

 

Cheers,  Brent Holben

 

The following highlights are discussed:

1.        Comment

2.        Operational Summary-(site managers and PIs please read 2-4)

3.        Field Maintenance

4.        Shipping, instrument return and calibration

5.        Personnel

6.        Website Updates

7.        AERONET Proposal Submitted

8.        Staff Research and Bibliography

 

Comment

One of the principle goals of developing AERONET into an international program was to provide validation of satellite aerosol retrievals representing a variety of aerosol types at a great diversity of geographic locations.  Our collective public domain data-base clearly has allowed us to achieve that goal.  So far AERONET data has provided published validation for aerosol retrievals from AVHRR, TOMS, POLDER, GOES, Landsat, SeaWiFS, GOMES and ATSR-2 (see bibliography).  Shortly we’ll be seeing published validations from MODIS, MISR, and perhaps ASTR.  Further validation studies of Airborne instruments and model simulations have also occurred.  In short, I feel that the program has been tremendously successful and all participants should feel gratified with their effort.  Thanks to all the PIs, PHOTON, AEROCAN, LTER, SIMBIOS, DOE, the many collaborators and especially the dedicated AERONET staff.

 

Operational Summary:

As of 12/5/00 there were 68 instruments operating in the field, 15 not functioning in the field and 32 on the roof at GSFC, for a total of 115.  AERONET staff calibrate and maintain the roof instruments, analyze field instrument performance weekly, troubleshoot any instruments as needed with the site managers, and coordinate shipping.  We also process and quality assure these data.  With this many instruments, we need the PI’s and site managers to be actively engaged with their instrument and data.  By all means please follow the weekly instrument maintenance inspection (~10 min); an ounce of prevention is worth a pound of cure.  See the website (http://aeronet.gsfc.nasa.gov/Operational/pictures/Checklist.html) for the checklist.

 

Field Maintenance:

We changed (effective 12/9/00) our automatic troubleshooting reports to facilitate field maintenance.  We have developed a comprehensive daily website troubleshooting report which is available for each transmitting instrument (GMS sites will be active in January).  We have eliminated the daily email reports to site managers but they will automatically be sent when certain problem thresholds are reached that require site manager attention.  Thus folks will not be overwhelmed with irrelevant information. AERONET staff make a comprehensive weekly evaluation of all instruments performance (usually on Monday) from which we’ll contact site managers directly to address the problems.  This is very time consuming so we ask your cooperation to provide an ounce of prevention by:

1.        Perform the weekly instrument inspection (http://aeronet.gsfc.nasa.gov/Operational/pictures/Checklist.html)

2.      Check your instrument on our webpage trouble shooting report once per week (suggest Monday) (http://aeronet.gsfc.nasa.gov/Operational/current_report.html) [~2 min]

3.        If you receive an individualized e-mail troubleshooting report, read it and take action as soon as possible

4.        Become familiar with our help page (Link under “Installation, Packing and Shipping Instructions”) on the AERONET website.

 

Tip:  We find the most common problems are associated with under charged batteries, incorrectly set clocks and tripped failsafe switches which sometimes arise when an instrument is exchanged.  We are all very much aware that active attentive site managers save the AERONET staff a great deal of time and greatly improves data collection.

 

Shipping, instrument return and calibration

Our turn-around for calibrating instruments for field readiness has varied from as little as three days to as much as 4 months, our goal is 4 weeks from the time of arrival to the time it’s shipped out the door.  Factors affecting our backlog, weather, the condition of instruments returned, the availability of replacement parts, and staff and facility schedules.  Delays associated with international shipments usually involve clearing customs.  To expedite the calibration of your field instrument please follow the list below which now appears on our website: http://aeronet.gsfc.nasa.gov/Operational/Active_intercal.html

 

1.        Pack sensor head, control box, sensor head cable, collimator, internal battery pack and cable connector panel.  Add the robot to speed roof access See (http://aeronet.gsfc.nasa.gov/Operational/pictures/packing.html) for directions. This is very important.

 

2.        Follow shipping directions  given on the website (http://aeronet.gsfc.nasa.gov/Operational/pictures/shipping.html) or contact Dee Jones (djones@aeronet.gsfc.nasa.gov). This is very important.

 

3.        Monitor progress at: http://aeronet.gsfc.nasa.gov/Operational/Active_intercal.html

 

4.        Priority concerns: contact Ross Nelson at ross@aeronet.gsfc.nasa.gov

 

5.        If you have more than one instrument, please send them individually and only as they need calibration, please don’t group them.

 

Personnel changes

Personnel changes have occurred relatively rapidly of late.  Our technician Adam Naji left in October and our senior Engineer and good friend, Nader Abuhassan, gave notice for a Jan. 1 departure.  I expect the transition to be smooth as Mikhail Sorokine, our development engineer, will temporarily assume Nader’s duties.  Our best wishes go Nader and Adam.  Dee Jones came on board in June as our Admin.  I’m sure most of you have communicated with her.

 

Website Updates

Ilya Slutsker has completed a major programming effort for tracking, assigning instrument ID’s, and transmission ID’s.  Although this has little effect for most PIs, it is a significant time saver for our staff and will aid in troubleshooting instruments that are not transmitting properly.  He will be turning his attention to the website which should significantly change its appearance, products available and organization.  Any suggestions for this upgrade will be appreciated and should be sent to Oleg Dubovik (dubovik@aeronet.gsfc.nasa.gov) who is coordinating the upgrade.  

Monthly domain summaries and analysis of our website hits may be obtained from http://aeronet.gsfc.nasa.gov/Webstats/wstats.html

 

AERONET Proposal Submitted

The AERONET program is a federation of independently funded PI’s and projects primarily glued together by the GSFC operation.  A proposal was submitted to NASA HQ for an additional five year funding cycle for AERONET GSFC.  The program was reviewed by the AERONET science steering committee in April resulting in a positive statement and recommendation for future operation.  The committee report is available on the AERONET website (http://aeronet.gsfc.nasa.gov/Publications/Conference.html).

 

Staff Research and Bibliography

The polarization data-base has largely been brought up to a quality assured status by Anne Vermeulen.  We expect to be presenting these data on the AERONET website in the new-year.  Similarly additional inversion products will appear on the website.  In this regard Dubovik’s two papers on inversions were published.  The group AOD climatology paper has been accepted and several field campaign papers by Eck, Smirnov and O’Neille were published since the last AERONET Quarterly.   Significant papers by Kaufman,(diurnal variation of AOD) and Tanre (optical properties of desert dust) have been published or accepted.  Please see the bibliography below and PDF files on the website.

Research activities include characterizing aerosol optical properties using all the retrievals from AERONET, collaboration with lidar retrievals, optical properties of specific airmasses.  We’ve completed our participation in the SAFARI2000 dry season campaign and are planning deployments for the Ace-Asia campaign which begins in March.

 

Bibliography

Dubovik, O., and M.D.King, A flexible inversion algorithm for retrieval of aerosol optical properties from sun and sky radiance measurements, J.Geophys.Res., 105, 20,673-20,696, 2000.

Dubovik, O., A.Smirnov, B.N.Holben, M.D.King, Y.J.Kaufman, T.F.Eck, and I.Slutsker, Accuracy assessments of aerosol optical properties retrieved from AERONET sun and sky radiance measurements, J.Geophys.Res., 105, 9791-9806, 2000a.

Eck, T.F., B.N.Holben, O.Dubovik, A.Smirnov, I.Slutsker, J.M.Lobert, and V.Ramanathan, Column integrated aerosol optical properties over the Maldives during the NE monsoon for 1998-2000, J.Geophys.Res., 2000 (submitted).

Eck, T.F., B.N. Holben, D.E. Ward, O. Dubovik, J.S. Reid, A. Smirnov, M.M. Mukelabai, N.C. Hsu, N.T. O'Neill, and I. Slutsker, Characterization of biomass burning aerosols in Zambia during the 1997 ZIBBEE Experiment,  J. Geophys. Res., 2000 (accepted)

Ferrare, R., S.Ismail, E.Browell, V.Brackett, M.Clayton, S.Kooi, S.H.Melfi, D.Whiteman, G.Schwemmer, K.Evans, P.Russell, J.Livingston, B.Schmid, B.Holben, L.Remer, A.Smirnov, and P.Hobbs, Comparison of aerosol optical properties and water vapor among ground and airborne lidars and sun photometers during TARFOX, J.Geophys.Res., 105, 9917-9934, 2000.

Higurashi, A., T.Nakajima, B.N.Holben, A.Smirnov, R.Frouin, and B.Chatenet, A study of global aerosol optical climatology with two channel AVHRR remote sensing, J. Clim., 13, 2011-2027, 2000.

Holben, B.N., D.Tanre, A.Smirnov, T.F.Eck, I.Slutsker, N.Abuhassan, W.W.Newcomb, J.Schafer, B.Chatenet, F.Lavenue, Y.J.Kaufman, J.Vande Castle, A.Setzer, B.Markham, D.Clark, R.Frouin, R.Halthore, A.Karnieli, N.T.O'Neill, C.Pietras, R.T.Pinker, K.Voss, G.Zibordi, An emerging ground-based aerosol climatology: Aerosol Optical Depth from AERONET, J. Geophys. Res., 2000 (accepted).

Hsu, N.C., J.R.Herman, O.Torres, B.N.Holben, D.Tanre, T.F.Eck, A.Smirnov, B.Chatenet, and F.Lavenu, Comparisons of the TOMS aerosol index with sunphotometer aerosol optical thickness: results and applications, J. Geophys. Res, 104, 6269-6280, 1999.

 

Kaufman, Y.J., B.N.Holben, D.Tanré, I.Slutzker, T.F.Eck, A.Smirnov, How well can aerosol measurements from the Terra morning polar orbiting satellite represent the daily aerosol abundance and properties?, Geoph. Res. Lett., 23, 3861-3864, 2000.

Kreidenweis S. M., L. A. Remer, R. Bruitjes, R. Kleidman, R. Halthore, B. N. Holben and O. Dubovik, "Observations of smoke aerosol from biomass burning in Mexico, J. Geophys. Res.,  2000 (accepted).

Kinne, S., B.N.Holben, T.F.Eck, A.Smirnov, O.Dubovik, I.Slutsker, U.Lohmann, S.Ghan, M.Chin, P.Ginoux, T.Takemura, R.Kahn, E.Vermote, D.Tanre, L.Stowe, O.Torres, M.Mischenko, How well do aerosol retrievals from satellites and representation in global circulation models match ground-based AERONET aerosol statistics, 2001 (in press).

Ouaidrari, H. and E.F. Vermote.  Operational atmospheric correction of Landsat TM data, Rem. Sens. Env., 70(1), 1999.

O'Neill, N.T., T.F.Eck, B.N.Holben, A.Smirnov, O.Dubovik, and A.Royer, Uni. and bi-modal size distribution influences on the variation of Angstrom derivatives in spectral and optical depth space, J. Geophys. Res., 2000a (accepted).

O'Neill, N.T., A.Ignatov, B.N.Holben, and T.F.Eck, The lognormal distribution as a reference for reporting aerosol optical depth statistics; Empirical tests using multi-year, multi-site AERONET sunphotometer data, Geophys.Res.Lett., 27, 3333-3336, 2000b.

O'Neill, N.T., T.F.Eck, B.N.Holben, A.Smirnov, A.Royer, and Z.Li, Optical properties of Canadian forest fire smoke derived from sunphotometry, J. Geophys. Res., 2000d (submitted).

Schmid, B., J.J.Michaslky, D.W.Slater, J.C.Barnard, R.N.Halthore, J.C.Liljegren, B.N.Holben, T.F.Eck, J.M.Livingston, P.B.Russell, T.Ingold, and I.Slutsker, Comparison of columnar water vapor measurements during the fall 1997 ARM Intensive Observation Period: solar transmittance methods, Appl. Opt., 2000 (submitted).

Smirnov, A., B.N.Holben, T.F.Eck, O.Dubovik, and I.Slutsker, Cloud screening and quality control algorithms for the AERONET data base, Rem. Sens. Env., 73(3), 337-349, 2000a.

Smirnov, A., B.N.Holben, D.Savoie, J.M.Prospero, Y.J.Kaufman, D.Tanre, T.F.Eck, and I.Slutsker, Relationship between column aerosol optical thickness and in situ ground based dust concentrations over Barbados, Geophys. Res. Lett., 27, 1643-1646, 2000b.

Smirnov, A., B.N.Holben, O.Dubovik, N.T.O'Neill, L.A.Remer, T.F.Eck, I.Slutsker, and D.Savoie, Measurement of atmospheric optical parameters on US Atlantic coast sites, ships and Bermuda during TARFOX, J. Geophys. Res., 105, 9887-9901, 2000d.

Smirnov, A., B.N.Holben, O.Dubovik, N.T.O'Neill, T.F.Eck, D.L.Westphal, A.K.Goroch, C.Pietras, and I.Slutsker, Atmospheric aerosol optical properties in the Persian Gulf region, Geophys.Res.Lett., 2000e (submitted).