The purpose of this paper is to review Release 4 (available Fall 2001) of the SSE data set. It is considered to be accurate for preliminary feasibility studies of renewable energy projects and is available, free-of-charge, over the Internet (http://eosweb.larc.nasa.gov/sse/). The data set is a continuous 10-year global climatology (1983-1993) of satellite-derived insolation and meteorology data. The irradiance and cloud data are derived from the International Satellite Cloud Climatology Project (ISCCP) D1 data set and processed through the Langley parameterized Shortwave Algorithm (LPSA) to derive surface radiation budget parameters. The meteorological parameters are processed from GEOS-1, supplied by the NASA Goddard Data Assimilation Office. GEOS-1 is a reanalysis product that blends surface and upper air observations with satellite retrievals. The data are processed on a 2.5o equal-area grid system and then interpolated to a 1o equal angle grid system for web site distribution. Release 4 contains more accurate estimates of resource parameters in comparison to previous releases. Also, additional solar and meteorological parameters, such as direct and diffuse radiation and wind estimates over various vegetative surfaces, have been included based on recommendations by the renewable energy industry.
Since June 1999, nearly 2000 users registered at the SSE web site and generated approximately 400,000 hits and 30,000 data document downloads. Release 3 (available since October 2000) is currently averaging 30,000 hits per month. Users include Shell, BP Amoco, Duke Solar Energy, Siemans Solar Industries, DuPont, International Financial Corporation, The World Bank, UNESCO, Winrock International, the Jet Propulsion Laboratory, the US Department of Energy, and the USDA Forest Service. Web links to the SSE web site include: Institute of Solar Energy (Madrid), Solar Electric Power Association, Maryland Energy Administration, Hawaii Department of Business, Economic Development and Tourism, Duke University Physics Department, NREL Renewable Resource Data Center, Solar Energy Association of Oregon, and Sustainable Minnesota. Through contacts with registered users, efforts are ongoing to continually refine the resource assessment data available on the SSE web site.