SRI

EPA summarizes SRI as “the relative steady-state surface temperature with respect to the standard white (SRI=100) and standard black (SRI=0) under the standard solar and ambient conditions.”

The Cool Roof Rating Council (CRRC):  http://www.coolroofs.org

SRI Calculator (enter Reflectance and Emissivity):
http://www.arkema-inc.com/index.cfm?pag=986