AERONET Quarterly

 

Welcome to the AERONET quarterly.

 

Highlights:

  • Project Growth remains on Hold
  • Field Maintenance Update
  • Photon News
  • AEROCAN News
  • AOD Climatology
  • Synergism on the web with non AERONET projects
  • New retrievals products/AERONET web page
  • Non-sphericity
  • Research papers/Field Programs
  • AGU Aerosol session

 

 

Project Growth:

Project growth remains capped for new instrument requests except in regions of poor spatial coverage that includes Eastern Europe, Asia and the southern oceans.  Slow growth also continues as prior commitments are honored and come on-line.  I appreciate everyone’s understanding of the situation. AERONET will be working with the Institute of Atmospheric Optics in Tomsk to develop a network in Russia expected to be eight sites. 

 

The overall federated network currently maintains approximately 175 instruments deployed at 125 permanent sites.  As of this writing 98 sites were reporting field data, 34 instruments are at GSFC and ~9 in Lille for calibration, and the remaining are in transit, awaiting deployment or in repair/maintenance.

 

 

Field Maintenance:

Our network is highly regarded by the scientific community for its accuracy and distribution of column integrated aerosol retrievals. Despite the processing and calibration that we support at Goddard, the results are only as good as the data collected in the field.  All in, data have been of exceptional quality, but we need to be vigilant in our field collection. Recently we received some instruments that contained months old spider webs in the collimators.  At worst this can cause us to reject these data for level 2.0 status. Often we can see the effects of webs in the data however there are cases when we cannot and it can bias the data.  Site managers and PIs, please check your collimators weekly.  If you clean the collimator, please let us know the date of the action.  Please note the revised weekly maintenance procedures available on the AERONET website (Operations, operating the sun photometer, weekly maintenance, procedures).

 

 

 

Instrumentation:

Mikhail Sorokin has successfully hardened an instrument for very cold weather (Barrow, AK that is currently operating well).  It’s a custom modification that could be used for extreme cases.

 

Cimel Electronique has nearly completed development and testing of a prototype instrument with a 1.6 mm channel in addition to the standard channels.  Improved electronics, RAM and air pressure.  Should this be accepted by AERONET it will provide important data for dust aerosol characterization. 

 

PHOTON news:  ~33 instruments  in western Europe and West Africa; primarily polarization instruments.  Developing an in-country calibration facility with links to GSFC calibration facility.  PI: Phillipe Goloub collaboration with LOA, CNRS and CNES.

 

AEROCAN News: Nine instruments are mostly distributed across southern Canada.  Planned sites include a very high latitude site at Resolute Bay on Cornwallis Island (Nunavut) a high latitude site at Kuujjuarapik, Quebec (on the east coast of Hudson's Bay across from the existing western Hudson Bay site at Churchill, Manitoba) and an urban-maratime site at Halifax, Nova Scotia. Recent investigations include intersunphotometer optical depth comparisons by Bruce McArthur at Bratt's Lake Saskatchewan and studies of the sunphotometric influences of forest fire smoke, Asian dust, the Fraser Vally (B.C.) pollution plume and thin cloud, spectral cloud screening.

PI: Norm O’Neill, co-PI Alain Royer, AEROCAN network coordinator; Jim Freemantle.

 

AOD climatology:  (DATA, Climatology 2.0):

Our web based AOD monthly climatology has been upgraded to include AOD for all wavelengths measured for all level 2.0 data.  Kudos to Dave Giles for developing this data set.  Please note that Pw is included in the climatology however the latest spectroscopic information is not included in our processing and that the uncertainty of our retrievals is ~±10%. Results of test applications of recent 940 nm region spectroscopy have actually increased the Pw differences between sun photometer retrievals and “ground truth’ (i.e. microwave radiometer).  Until general scientific acceptance of ‘improved’ H2O spectroscopy is achieved, AERONET will maintain the current processing.

 

Complimentary Data:

We are working with other groups to include complimentary data products on the AERONET website on an exploratory basis.  This includes back trajectories (GSFC Code 916 Shadoz Project) and lidar extinction profiles (GSFC Code 912, MPLNET).  These data appear for single days under the AOD window.

 

New Retrieval Products/Quality assured data products:

Fine and coarse mode AOD, SSA, Cv, Rv and Re are provisionally available through the demonstrat.  They are expected to be available on the AEROENT website by the end of summer as a level 2.0 product. 

 

Non-sphericity:

Inversion products from Dubovik’s new non-sphereical inversion code is in the research and development phase.  A GRL paper is accepted. 

 

Recent Papers:

Eight papers using AERONET data appeared in the Feb. Journal of the Atmospheric Sciences, two JGR special issues are in preparation for the SAFARI2000 and PRIDE campaigns that will include several AERONET papers.  Two LBA papers were accepted by JGR and GRL.

 

Dubovik, O., B.N.Holben, T.F.Eck, A.Smirnov, Y.J.Kaufman, M.D.King, D.Tanre, and I.Slutsker, 2002: Variability of absorption and optical properties of key aerosol types observed in worldwide locations, J.Atm.Sci., 59, 590-608 .

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, 2002: Atmospheric Aerosol Optical Properties in the Persian Gulf, J. Atm. Sci., 59, 620-634.

Smirnov, A., B.N.Holben, Y.J.Kaufman, O.Dubovik, T.F.Eck, I.Slutsker, C.Pietras, and R.Halthore, 2002: Optical Properties of Atmospheric Aerosol in Maritime Environments, J.Atm.Sci., 59, 501-523.

 

AGU Special Session:

A special session on all aspects of AERONET related research will be held in Washington DC on May 30.  There will be 11 oral papers and 22 posters.  The abstracts may be viewed on the AGU website: spring meeting, atmosphere, Special Session, A08

 

Thanks Everyone!

 

Brent Holben