Status of the ISO Draft Standard for Determining Solar Irradiances (CD 21348)

A draft international standard has been developed through ISO TC20/SC14/WG4 to specify all representations of solar irradiances. Because solar irradiance measurements and modeling are constantly evolving through improved instrumentation, measurement techniques, and modeling capabilities, the draft standard has been written as a process-based standard. This format is designed to encourage the ongoing developments in the area of solar irradiance determination. The draft standard covers all representations of solar irradiances and is applicable to measurements, reference spectra, empirical models, and physics-based models. The purpose of the standard is to provide a common specification for all solar irradiances for use by space systems materials and environment users. A solar irradiance product or specification would be compliant with the standard if four criteria are followed. First, solar irradiances are reported, at the minimum, in SI units of Watts per square meter corrected to 1 AU. Second, the method of determining irradiances would be documented for data collection, processing, archiving, validation, accuracy, precision, methodology, and algorithm information. Where applicable, a description of proxies and independent data sets used in the derivation of empirical models, including the rationale for proxy selection, and the mathematical formulation for numerical models would be provided. Third, a compliant data set or model would be published in an internationally-available peer review journal. Fourth, the compliant data set or model would be archived in a method consistent with current technology that ensures international accessibility. A draft of the solar irradiance standard is publicly available for comment at the web site http://www.SpaceWx.com/.