AERONET - A FEDERATED INSTRUMENT NETWORK AND DATA ARCHIVE FOR AEROSOLCHARACTERIZATION

The concept and description of a remote sensing aerosol monitoring net work initiated by NASA, de;eloped to support NASA, CNES, and NASDA's E arth satellite systems under the name AERONET and expanded by national and international collaboration, is described. Recent development of weather-resistant automatic sun and sky scanning spectral radiometers enable frequent measurements of atmospheric aerosol optical properties and precipitable water at remote sites. Transmission of automatic mea surements via the geostationary satellites GOES and METEOSATS' Data Co llection Systems allows reception and processing in near real-time fro m approximately 75% of the Earth's surface and with the expected addit ion of GMS, the coverage will increase to 90% in 1998. NASA developed a UNIX-based near real-time processing, display emerging global databa se. Information on the system is available on the project homepage, ht tp://spamer.gsfc.nasa.gov. The philosophy of an open access database, centralized processing and a user-friendly graphical interface has con tributed to the growth of international cooperation for ground-based a erosol monitoring and imposes a standardization for these measurements . The system's automatic data acquisition, transmission, and processin g facilitates aerosol characterization on local, regional, and global scales with applications to transport and radiation budget studies, ra diative transfer-modeling and validation of satellite aerosol retrieva ls. This article discusses the operation and philosophy of the monitor ing system, the precision and accuracy of the measuring radiometers, a brief description of the processing system, and access to the databas e. (C) Elsevier Science Inc., 1998.