The SOLAR2000 empirical solar irradiance model and forecast tool

SOLAR2000 is a collaborative project for accurately characterizing solar ir radiance variability across the spectrum. A new image- and full-disk proxy empirical solar irradiance model, SOLAR2000, is being developed that is val id in the spectral range of 1-1,000,000 nm for historical modeling and fore casting throughout the solar system. The overarching scientific goal behind SOLAR2000 is to understand how the Sun varies spectrally and through time from X-ray through infrared wavelengths. This will contribute to answering key scientific questions and will aid national programmatic goals related t o solar irradiance specification. SOLAR2000 is designed to be a fundamental energy input into planetary atmosphere models, a comparative model with nu merical/first principles solar models, and a tool to model or predict the s olar radiation component of the space environment, It is compliant with the developing International Standards Organization (ISO) solar irradiance sta ndard. SOLAR2000 captures the essence of historically measured solar irradi ances and this expands our knowledge about the quiet and variable Sun inclu ding its historical envelope of variability. The implementation of the SOLA R2000 is described, including the development of a new EUV proxy, E10.7, wh ich has the same units as the commonly used F10.7. SOLAR2000 also provides an operational forecasting and global specification capability for solar ir radiances and information can be accessed at the website address of http:// www.spacenvironment.net. (C) 2000 Elsevier Science Ltd. All rights reserved .