AERONET (AErosol RObotic NETwork) is an optical ground based aerosol
monitoring network and data archive supported by NASA's Earth
Observing System and expanded by federation with many non-NASA
institutions. The network hardware consists of identical automatic
sun-sky scanning spectral radiometers owned by national agencies and
universities. AERONET sites are located around the world. Data is
available from the AERONET web site at:

http://aeronet.gsfc.nasa.gov